HomeMy WebLinkAbout20230613140321216 Canyon Loop Trail Improvement CPPS_CSBSS HMMP FINAL June 2023HABITAT MITIGATION AND
MONITORING PROGRAM
Canyon Loop Trail Improvement Project
City of Diamond Bar, Los Angeles County,
California
Project Proponent:
City of Diamond Bar
21810 Copley Drive
Diamond Bar, CA 91765
Contact: Mr. Ryan Wright
909-839-7061
Prepared for the City of Diamond Bar
Prepared By:
Michael Baker International
Ryan Phaneuf, CERP, CAE, sUAS Anisha Malik, CERP, SITES AP
June 2023
Canyon Loop Trail Improvement Project
Habitat Mitigation and Monitoring Program i
Table of Contents
Section 1 INTRODUCTION......................................................................................... 1
1.1 Responsible Parties .................................................................................... 1
1.2 Pr oject Location .......................................................................................... 1
1.3 Project Description ...................................................................................... 1
1.4 Summary of Impacted Areas ....................................................................... 4
Section 2 RESTORATION GOALS............................................................................. 6
2.1 Responsibilities ........................................................................................... 6
2.2 Type(s) and Area(s) to be Established, Restored, Enhanced, and/or
Preserved ................................................................................................... 6
2.3 Functions and Values of Habitat Type(s) to be Established, Restored,
Enhanced, and/or Preserved ....................................................................... 9
2.4 Time Lapse Between Impacts and Expected Restoration Success ............. 10
2.5 Estimated Total Cost of Restoration........................................................... 10
Section 3 DESCRIPTION OF PROPOSED RESTORATION AND ENHANCEMENT
SITES ....................................................................................................... 11
3.1 Site Selection Process .............................................................................. 11
3.2 Location and Size of Restoration and Enhancement Sites.......................... 12
3.3 Ownership Status...................................................................................... 12
3.4 Existing Functions and Values of the Restoration and Enhancement .......... 12
3.4.1 Upland Mustards and Other Ruderal Forbs (Holland Equivalent: Non-
Native Grassland; Code 42200) ..................................................... 15
3.4.2 California Sagebrush – Black Sage Scrub (Holland Equivalent: Diegan
Coastal Sage Scrub; Code 32500) ................................................. 15
3.4.3 Disturbed California Sagebrush – Black Sage Scrub (Holland
Equivalent: Diegan Coastal Sage Scrub; Code 32500) ................... 15
3.5 Present and Proposed Uses of the Restoration Site and All Adjacent Areas 16
3.6 Reference Site(s) ...................................................................................... 16
Section 4 RESTORATION SITE IMPLEMENTATION PROGRAM ............................ 20
4.1 Basis for Success...................................................................................... 20
4.2 Responsible Parties .................................................................................. 20
4.3 Financial Assurances ................................................................................ 20
4.4 Implementation Schedule .......................................................................... 20
4.5 Contracting Requirements ......................................................................... 20
4.6 Site Construction, Preparation, and Monitoring .......................................... 21
4.6.1 Pre -Construction Meeting and Contractor Training Program............ 21
Table of Contents
Canyon Loop Trail Improvement Project
Habitat Mitigation and Monitoring Program ii
4.6.2 Site Fencing and Buffer Flagging .................................................... 21
4.6.3 Nesting Bird Clearance Surveys ..................................................... 22
4.6.4 Clearing and Grubbing ................................................................... 22
4.6.5 Weed Abatement prior to Planting and Seeding .............................. 22
4.6.6 Planting ......................................................................................... 24
4.7 Planting Plan............................................................................................. 24
4.7.1 Plan t and Seed Palettes ................................................................. 24
4.7.2 Seed Installation ............................................................................ 26
4.7.3 Planting Container Stock ................................................................ 26
4.7.4 Cactus Pad Cuttings....................................................................... 27
4.8 Irrigation Plan ............................................................................................ 28
4.9 Signage .................................................................................................... 29
4.10 As-Built Conditions .................................................................................... 29
Section 5 MAINTENANCE ACTIVITIES DURING THE MONITORING PERIOD ........... 30
5.1 Maintenance Activities............................................................................... 30
5.1.1 Plant Inspection ............................................................................. 30
5.1.2 Removal of Exotic Plant Species .................................................... 30
5.1.3 Replacement of Native Plant Species ............................................. 31
5.1.4 Trash and Debris Removal ............................................................. 31
5.1.5 Irrigation Frequency ....................................................................... 31
5.2 Responsible Parties .................................................................................. 32
5.3 Maintenance Schedule .............................................................................. 32
Section 6 MONITORING PROGRAM AND DOCUMENTATION................................ 33
6.1 Performance Standards, Target Dates, and Success Criteria ..................... 33
6.2 Target Functions and Values ..................................................................... 34
6.3 Monitoring Methods................................................................................... 34
6.3.1 Qualitative Monitoring..................................................................... 34
6.3.2 Quantitative Monitoring................................................................... 34
6.4 Monitoring Schedule.................................................................................. 35
6.5 Annual Monitoring Reports ........................................................................ 36
6.6 Preservation Mechanism ........................................................................... 37
Se ction 7 COMPLETION OF RESTORATION.............................................................. 38
7.1 Notification of Completion.......................................................................... 38
7.2 Agency Confirmation ................................................................................. 38
7.3 Long-Term Maintenance ........................................................................... 38
Se ction 8 CONTINGENCY MEASURES ................................................................... 39
Table of Contents
Canyon Loop Trail Improvement Project
Habitat Mitigation and Monitoring Program iii
8.1 Initiating Procedures.................................................................................. 39
8.2 Alternative Locations for Contingency Restoration ..................................... 39
8.3 Funding Mechanism .................................................................................. 39
8.4 Responsible Parties .................................................................................. 39
Section 9 REFERENCES ......................................................................................... 40
LIST OF TABLES
1. Summary of Impacts to Vegetation Communities .....................................................4
2. Mitigation Summary .................................................................................................5
3. Estimated Costs ....................................................................................................10
4. Coast Prickly Pear Scrub Plant and Seed Palette ...................................................25
5. California Sagebrush – Black Sage Scrub Seed Palette .........................................25
6. Maintenance Schedule ..........................................................................................32
7. CPPS Restoration Performance Standards ............................................................33
8. CSBSS Enhancement Performance Standards ......................................................33
LIST OF FIGURES
1. Regional Vicinity Map ..............................................................................................2
2. Site Vicinity Map......................................................................................................3
3. Restoration Project Site ...........................................................................................7
4. Enhancement Project Sites......................................................................................8
5. Restoration Site Photographs ................................................................................13
6. Enhancement Site Photographs.............................................................................14
7. Reference Site Locations.......................................................................................18
8. Reference Site Photographs ..................................................................................19
APPENDIX
A. CDFW Comments on Canyon Loop Trail Improvement Project
B. Coastal California Gnatcatcher Avoidance and Minimization Strategy for the Canyon
Loop Trail Improvement Project
Canyon Loop Trail Improvement Project
Habitat Mitigation and Monitoring Program 1
Section 1 INTRODUCTION
This Habitat Mitigation and Monitoring Program (Program) has been prepared in accordance
with the proposed project description. The purpose of this Program is to describe both the
voluntary restoration and the compensatory mitigation for permanent impacts to coast prickly
pear scrub (CPPS) and California sagebrush – black sage scrub (CSBSS) associated with
the Canyon Loop Trail Improvement Project (Project). Overall, this Program contains the
methods to be used during implementation of the restoration and enhancement.
1.1 Responsible Parties
Project Proponent: Agent Name:
City of Diamond Bar Michael Baker International
21810 Copley Drive 5 Hutton Centre Drive, Suite 500
Diamond Bar, CA 9165 Santa Ana, CA 92707
Contact: Ryan Wright Contact: Anisha Malik, CERP, SITES AP
Phone: 909-839-7061 Phone: 949-855-3674
Email: RWright@DiamondBarCA.gov Email: anisha.malik@mbakrerintl.com
1.2 Project Location
The Project is generally located south of State Route 60, east of State Route 57, north of
Grand Avenue, and west of Chino Hills Parkway in the City of Diamond Bar, Los Angeles
County, California. The project is depicted in Sections 11, 14, and 15 of Township 2 South,
Range 9 West, on the U.S. Geological Survey’s (USGS) San Dimas, California 7.5-minute
quadrangle (refer to Figure 1, Regional Vicinity, and Figure 2, Site Vicinity). Specifically, the
Project is located along the existing Canyon Loop Trail within Summitridge Park (refer to
Figure 3, Restoration Project Site, and Figure 4, Enhancement Project Sites).
1.3 Project Description
As detailed in the project IS/MND, the Canyon Loop Trail Project consists of a series of
improvements to the existing Canyon Loop Trail. The Project realigned the trail, improved
drainage to minimize erosion of the trail, enhanced the use of the trail where the gradients
were steep, re-graded cross slopes, and considered amenities such as directional and
interpretive signage, rest areas with benches, small shade shelters, climbing steps with
cobblestone swale channelization, and water diverting improvements where necessar y. Such
trail improvements reward hikers and visitors with 360-degree views of open space. Although
the trail was widened as necessary to ensure a consistent five-foot width, the existing trail was
not a high-usage amenity, and post-project conditions are not expected to increase the
average numbers of daily trail users.
SAN BERNARDINO COUNTY
RIV
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SID
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O
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Y
LOS ANGELES COUNTY
ORANGE COUNTY
Regional Vicinity
Figure 1
°0 52.5
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HABITAT MITIGATION AND MONITORING PROGRAM
Source: ArcG IS Online, 2018
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Project Location
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Site Vicinity
Figure 2
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Restoration Project Site (0.25 acre)
CANYON LOOP TRAIL IMPROVEMENT PROJECT
HABITAT MITIGATION AND MONITORING PROGRAM
Source: USGS 7.5-Minute topographic quadrangle maps: Ontario, Prado Dam, San Dimas, and Yorba Linda, California (2018)
Introduction
Canyon Loop Trail Improvement Project
Habitat Mitigation and Monitoring Program 4
1.4 Summary of Impacted Areas
The Project has resulted in the permanent removal of vegetated habitat directly adjacent to
the existing trail. However, in most areas, the trail is already generally wide enough for the
Project’s goals, resulting in minimal need for additional widening and very minimal disturbance
to surrounding vegetation. Acreages of vegetation communities that will be permanently lost
as a result of this project are presented in Table 1, below.
Table 1: Summary of Impacts to Vegetation Communities
Vegetation Communities Permanent Impacts (acres)*
California Sagebrush – Black Sage
Scrub 0.02
Coast Live Oak Woodland and Forest 0.01
Coast Prickly Pear Scrub 1 0.02
Disturbed 0.20
Disturbed California Sagebrush –
Black Sage Scrub 0.07
Scrub Oak Chaparral 0.01
TOTAL 0.31
*Total may not sum due to rounding.
The California Department of Fish and Wildlife (CDFW) reviewed the Project’s Mitigated
Negative Declaration (MND) and provided a comment letter to the City of Diamond Bar on
November 13, 2020 (Appendix A, CDFW Comments on Canyon Loop Trail Improvement
Project). Comment #2 required that the City of Diamond Bar mitigate the permanent loss of
sensitive vegetation communities as described in the California Natural Community List
(CDFW 2021). Of the on-site vegetation communities that could support the federally
threatened coastal California gnatcatcher (CAGN; Polioptila californica californica), CPPS
(Holland Equivalent: Diegan Coastal Sage Scrub; Code: 32500) is considered a sensitive (S3)
community by the CDFW requiring mitigation. To comply with this request, Michael Baker
contacted the nearby Soquel Canyon Mitigation Bank (SCMB) on behalf of the City of
Diamond Bar to determine if mitigation credits for the loss of 0.05 acre 2 of CPPS were
available. The SCMB does not have any remaining credits to mitigate for the loss of this
community. As a result, the City of Diamond Bar has agreed to mitigate for the loss of CPPS
through on-site restoration at an anticipated 5:1 ratio. The permanent impacts for the proposed
Canyon Loop Trail Improvement Project and the CDFW required mitigation acreage and ratio
are identified in Table 2, below.
1 State Rarity Rank S3 Sensitive Natural Community (California Department of Fish and Wildlife [CDFW] 2021).
2 0.05 acre of loss of CPPS was proposed based on original impact estimates. Following construction activities,
impacts to CPPS were determined to be less than originally anticipated, totaling 0.02 acre.
Introduction
Canyon Loop Trail Improvement Project
Habitat Mitigation and Monitoring Program 5
Although it is not considered a sensitive community by CDFW, CSBSS (S4, Holland
Equivalent: Diegan Coastal Sage Scrub; Code: 32500) and Disturbed California Sagebrush –
Black Sage Scrub (DCSBSS) have potential to support CAGN. As a result, the City of
Diamond Bar has agreed to mitigate for the loss of CSBSS/DCSBSS through on-site
enhancement at an anticipated 1.5:1 ratio. The permanent impacts for the proposed Canyon
Loop Trail Improvement Project and the CDFW required mitigation acreage and ratio are
identified in Table 2, below.
Table 2. Mitigation Summary
Project Impact Impact Area
(acres) Mitigation Type/Location Mitigation Area
(acres)
Mitigation
Ratio
Permanent
Impact to CPPS
0.02
On -site (within Summitridge Park)
restoration of CPPS 0.10-acre CPPS
5:1
Permanent
Impact to
CSBSS
0.02 On -site (within Summitridge Park)
Enhancement of CSBSS 0.03-acre CSBSS 1.5:1
Permanent
Impact to
DCSBSS
0.07 On -site (within Summitridge Park)
Enhancement of CSBSS 0.11-acre CSBSS 1.5:1
Total 0.11 On-site restoration of CPPS / On -
site Enhancement of CSBSS
0.10- acre CPPS /
0.14-acre CSBSS 5:1 / 1.5:1
Canyon Loop Trail Improvement Project
Habitat Mitigation and Monitoring Program 6
Section 2 RESTORATION GOALS
The purpose of this Program is to define the restoration goals and approach to the restoration
of CPPS and enhancement of CSBSS for the Canyon Loop Trail Improvement Project.
2.1 Responsibilities
The City will be responsible for the funding of the restoration and enhancement effort and
acquiring staff to implement the Project. The City will be consulted annually with the
submission of monitoring memos . The City will be included with the regulatory agencies for
the final approval of the project in Year 5.
The installation contractor and restoration maintenance contractor shall both be experienced
with restoration and enhancement projects to act in the best interest of the native vegetation
and wildlife within the area. The Project Restoration Ecologist shall be familiar with the Project
and experienced working within the City.
2.2 Type(s) and Area(s) to be Established, Restored, Enhanced,
and/or Preserved
The Program consists of the restoration of an overall 0.10-acre of disturbed uplands within
Summit ridge Park in the City of Diamond Bar (refer to Figure 3, Restoration Project Site).
Restoration will consist of restoring the Project Restoration Site with a native plant palette and
removing exotic species. The Project Restoration Site is located approximately 900 feet to the
northeast of the Project site impact area. The Project Restoration site generally consists of
exotic upland forbs and remnant patches of disturbed coastal sage scrub (DCSS).
The Program also consists of the enhancement of an overall 0.14-acre of DCSBSS within
Summitridge Park in the City of Diamond Bar. The enhancement activities will take place in
two separate sites, Site A (0.05-acre ) and Site B (0.09-acre ), both located along Canyon Loop
Trail (refer to Figure 4, Enhancement Project Sites). Enhancement will consist of enhancing
the Project Enhancement Sites with a native plant seed palette and removing exotic species.
The Project Enhancement Sites are located adjacent to the Project site impact are a, and
generally consist of black sage (Salvia mellifera), California sagebrush (Artemisia californica),
and exotic upland forbs.
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34.00372-117.797076
34.005713-117.794906
Restoration Project Site
Figure 3
°0 10050
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Restoration Project Site (0.1 0 a cre)
!>Refe re nce Point
CANYON LO OP TRAIL IMPROVEMEN T PRO JECT
HABITAT MITIGATION AND MO NITO RING PROGRAM
Source: Nearm ap (05/2022)
Ridge Route Trail
!>
!>34.00435-117.796521
34.001951-117.799171
Enhancement Project Sites
Figure 4
°0 12060
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Enh ancement Proje ct Sites (0.1 4 acre)
!>Refe re nce Point
CANYON LO OP TRAIL IMPROVEMEN T PRO JECT
HABITAT MITIGATION AND MO NITO RING PROGRAM
Source: Nearm ap (05/2022)Can y onLoopTrail
Site A
Site B
Restoration Goals
Canyon Loop Trail Improvement Project
Habitat Mitigation and Monitoring Program 9
2.3 Functions and Values of Habitat Type(s) to be Established,
Restored, Enhanced, and/or Preserved
In its current state, the Project Restoration Site is dominated by exotic and invasive plant
species, including short podded mustard (Hirschfelida incana) and tocalote (Centaurea
melitensis). Although the Project Restoration Site itself is dominated by non-native and
invasive vegetation, adjacent areas are dominated by native plant communities, including blue
elderberry stands, coast live oak woodland and forest, disturbed California sagebrush – black
sage scrub, scrub oak woodland, and CPPS. Restoration of the target site will improve
connectivity between existing stands of native vegetation, as well as increase the continuity
of existing adjacent stands. Restoration of the target site will also increase the overall diversity
of native habitat types within the area and reduce the connectivity between stands dominated
by non-native and invasive vegetation.
The Restoration Project Site will be restored to replicate historical conditions of the
surrounding habitat to the extent practicable, by utilizing a CPPS reference site located less
than one mile to the southwest within Summitridge Park. A general description of the reference
site is provided in Section 3.7, Reference Site(s). Restoration to the historical conditions of
thriving CPPS vegetation will increase the overall habitat value within the area, improving the
quality of habitat available for plant and wildlife species that have historically inhabited the
area.
The Enhancement Project Sites are characterized by a mix of native and exotic vegetation,
including black sage, California sagebrush, and short podded mustard. Adjacent areas consist
of similar vegetation composition, with scrub oak chaparral, coast live oak woodland and
forest, and CPPS vegetation communities within the vicinity of the trail and Project impact
area. Enhancement of the target site will improve connectivity between existing stands of
native vegetation, as well as increase the continuity of existing adjacent stands. Enhancement
of the target site will reduce the connectivity between stands dominated by non-native and
invasive vegetation, allowing CSBSS to establish as the dominant vegetation type in the
enhanced areas.
The Enhancement Project Site will be enhanced to replicate the conditions of healthier
adjacent stands of CSBSS habitat to the extent practicable, by utilizing a CSBSS reference
site located approximately 0.01 mile to the west within Summitridge Park, along the Canyon
Loop trail. A general description of the reference site is provided in Section 3.7, Reference
Site(s). Enhancement to replicate conditions of healthy CSBSS vegetation will increase the
overall habitat value within the area, improving the quality of habitat available for plant and
wildlife species that have historically inhabited the area.
Restoration Goals
Canyon Loop Trail Improvement Project
Habitat Mitigation and Monitoring Program 10
Based on the results of focused bird surveys conducted by Michael Baker International in
2020, a minimum of five (5) CAGN territories and five (5) cactus wren (Campylorhynchus
brunneicapillus; CACW) territories were documented within a 500-foot survey area around the
existing Canyon Loop Trail (Michael Baker International 2020). Although the CACW
documented on-site were not believed to be the sensitive (CDFW Species of Special Concern;
SSC) coastal cactus wren (Campylorhynchus brunneicapillus sandiegensis), the presence of
CACW and CAGN denotes the suitability of the local habitat for these species. Restoration
and enhancement of the target sites to historical and adjacent conditions of high quality
CPPS/CSBSS habitat is expected to provide an overall improvement in local habitat quality
for CACW and CAGN, as well as an increase in the acreage of suitable habitat for the species.
The installation of native cactus species and seeding other native vegetation is expected to
provide increased habitat structure and foraging area, both of which represent a benefit to
CACW and CAGN when compared with the highly degraded nature of the Restoration an d
Enhancement Project Sites in their current states.
2.4 Time Lapse Between Impacts and Expected Restoration
Success
The restoration and enhancement activities will be implemented following other site
improvements outlined in the project description. The Project Restoration and Enhancement
Sites will be subject to maintenance and monitoring for five years, after which the sites are
expected to meet the final performance criteria.
2.5 Estimated Total Cost of Restoration
It is anticipated that installation and maintenance will be completed by contract construction
crews. The estimated cost of installation, maintenance, and monitoring of the Project
Restoration and Enhancement Site s is approximately $381,785. For a full breakdown of
estimated costs, refer to Table 3, Estimated Costs, below.
Table 3: Estimated Costs
Mitigation Components Estimated Costs
Implementation $95,000
5 Year Maintenance $180,000
5 Year Monitoring $56,785
Grand Total $331,785
Canyon Loop Trail Improvement Project
Habitat Mitigation and Monitoring Program 11
Section 3 DESCRIPTION OF PROPOSED
RESTORATION AND
ENHANCEMENT SITE S
3.1 Site Selection Process
The Project consists of restoration and enhancement of disturbed uplands to replicate
historical conditions represented by the CPPS and CSBSS reference sites. Site selection was
determined based on several factors, including proximity to the impact area (within
Summitridge Park or along Canyon Loop Trail), site ownership (owned by the City), existing
easements, proximity to accessible trails or access roads, appropriate slope aspect, existing
vegetation within the Project Restoration Site, and existing adjacent stands of vegetation.
Michael Baker restoration ecologists Ryan Phaneuf and Trina Ming conducted baseline
assessments of potential restoration areas on July 5 and July 26, 2022. Baseline assessments
consisted of on-site investigations of potential restoration and enhancement areas located
along the trails within Summitridge Park, including observations of plant species and
vegetative cover, proximity to access roads and adjacent structures, photographic
documentation, and GPS points to record approximate restoration area boundaries and slope
aspect information. A desktop analysis was performed based on the results of the two baseline
assessments and potential restoration and enhancement sites were ranked according to
feasibility and suitability for CPPS restoration and CSBSS enhancement.
The Project Restoration Site was selected due first to its appropriate southerly slope aspect
f or accommodating CPPS. CPPS generally inhabits slopes with a southerly, south westerly,
or occasionally south easterly aspect (Rea and Weaver 1990). Second, the Project
Restoration Site is dominated primarily by exotic, invasive plant species, but with native plant
dominated stands of vegetation adjacent. Remnant stands of prickly pear cactus (Opuntia
littoralis) were also observed along the southern (downslope) margin of the Project
Restoration Site. Given the degraded nature of the site and the potential to improve
connectivity and continuity of native vegetation stands, as well as the presence of key plant
species found at the reference site location, the Project Restoration Site was determined to
have an appropriate vegetation composition for CPPS restoration. The Project Restoration
Site is situated approximately 80 feet south of a trail with access for vehicles from a gate on
nearby Peak Court. The Project Restoration Site is located within a City-owned parcel, more
than 200 feet from existing structures and outside of any known easements.
The Project Enhancement Sites were selected due to their species composition and location
along Canyon Loop Trail within Summitridge Park. The Project Enhancement sites are well
suited for enhancement, given their mix of existing native and exotic vegetation cover, as well
as proximity to nearby high quality CSBSS habitat. The Project enhancement sites are
Description of Proposed Restoration Site
Canyon Loop Trail Improvement Project
Habitat Mitigation and Monitoring Program 12
situated along Canyon Loop Trail, within a City-owned parcel, more than 200 feet from existing
structures and outside of any known easements.
3.2 Location and Size of Restoration and Enhancement Sites
The Project Restoration Site is located within Summitridge Park in the City of Diamond Bar,
California, approximately 80 feet southwest of Ridge Route Trail and is approximately 0.10
acre s. The center of the site is located at Universal Transverse Mercator (UTM) coordinates
34.004625°, -117.796008°.
The Project Enhancement Sites are located within Summitridge Park in the City of Diamond
Bar, California, adjacent to Canyon Loop Trail. The centers of the Project Enhancement Sites
are located at UTM coordinates 34.003182°, -117.796614° (Site A) and 34.002963°, -
117.798985° (Site B) and are 0.05 and 0.09 acre in size, respectively.
3.3 Ownership Status
The Project Restoration Site is located on a natural hillside within the open space area of
Summitridge Park. Ridge Route Trail, maintained by the City of Diamond Bar, runs
immediately to the northeast of the site. The City of Diamond Bar owns and manages the
property. There are no ownership, legal issues, or known encumbrances that pose constraints
to the Project.
The Project Enhancement Sites are located adjacent to Canyon Loop Trail, within the open
space area of Summitridge Park. The trail is maintained by the City of Diamond Bar. The City
of Diamond Bar owns and manages the property. There are no ownership, legal issues, or
known encumbrances that pose constraints to the Project.
3.4 Existing Functions and Values of the Restoration and
Enhancement
Existing functions and values include, but are not limited to, marginal habitat for local wildlife,
marginal habitat for native plant species, and buffer for more high-quality native plant
communities farther down slope from Ridge Route Trail and along Canyon Loop Trail;
however, the functions and values are currently impaired by significant exotic vegetation
cover. The Project Restoration Site currently has lower habitat value than surrounding areas
due to low cover from native species, poor buffer condition, and non-native vegetation with
minimal plant layers, co-dominant species, and horizontal interspersion. The Project
Enhancement sites are heavily invaded with non-native vegetation. Photographs of the
existing Project Restoration and Enhancement Site s and corresponding locations are
provided in Figure 5, Restoration Site Photographs, and Figure 6, Enhancement Site
Photographs.
08/19/2022 JN 178669
PhotoPoint1 –Looking south (downslope) into the interior of the Project Restoration
Site.
CANYON LOOP TRAIL IMPROVEMENT PROJECT • HABITAT MITIGATION AND MONITORING PROGRAMFigure 5 - Restoration Site Photographs
July 2022
PhotoPoint2 –Looking southwest (downslope) Into the interior of the Project Restoration
Site
PhotoPoint3 –Looking southeast down Ridge Route Trail, with the Project Restoration
Site in the right of the photo frame (downslope).
PhotoPoint4 –Looking west down Ridge Route Trail, with the Project Restoration Site in
the left of the photo frame (downslope).
08/19/2022 JN 178669
PhotoPoint1 –Looking northwest along Canyon Loop Trail into the ProjectEnhancement
Site A.
CANYON LOOP TRAIL IMPROVEMENT PROJECT • HABITAT MITIGATION AND MONITORING PROGRAMFigure 6 - Enhancement Site Photographs
July 2022
PhotoPoint2 –Looking east Into the Project Enhancement Site A.
PhotoPoint3 –Looking northeast into the Project Enhancement Site B.PhotoPoint4 –Looking south west into the Project Enhancement Site B.
Description of Proposed Restoration Site
Canyon Loop Trail Improvement Project
Habitat Mitigation and Monitoring Program 15
3.4.1 Upland Mustards and Other Ruderal Forbs (Holland Equivalent: Non-
Native Grassland; Code 42200)
The 0.10-acre Project Restoration Site currently consists of upland mustards and other ruderal
forbs vegetation. This non-native plant community is dominated by black mustard (Brassica
nigra), with other species such as tocalote, coastal wild radish (Raphanus sativus), Italian
thistle (Carduus pycnocephalus), wild oat (Avena fatua), and Italian rye grass (Festuca
perennis) occurring as less frequent sub-dominants. No overstory or shrubs were present
within the vegetation community, with the exception of small remnant stands of California
sagebrush and prickly pear cactus growing on the margin of the site.
3.4.2 California Sagebrush – Black Sage Scrub (Holland Equivalent: Diegan
Coastal Sage Scrub; Code 32500)
California sagebrush – black sage scrub vegetation is located adjacent to the Project
Enhancement Sites along Canyon Loop Trail. The majority of this vegetation community is
dominated by California sagebrush and black sage with other shrubs such as white sage
(Salvia apiana), deerweed (Acmispon glaber), and California buckwheat (Eriogonum
fasciculatum) occurring as less frequent sub-dominants. Due to the high density of shrubs
within the vegetation community, little to no herbaceous cover is present.
3.4.3 Disturbed California Sagebrush – Black Sage Scrub (Holland
Equivalent: Diegan Coastal Sage Scrub; Code 32500)
The 0.14-acre Project Enhancement Sites currently consist of disturbed California sagebrush
– black sage scrub vegetation. This vegetation community is similar in composition and
generally in close proximity to the California sagebrush – black sage scrub found within the
vicinity of Canyon Loop Trail but also contains short podded mustard, black mustard and
tocalote as co-dominant species, in many areas completely dominating the ground cover
between native shrubs.
Description of Proposed Restoration Site
Canyon Loop Trail Improvement Project
Habitat Mitigation and Monitoring Program 16
3.5 Present and Proposed Uses of the Restoration Site and All
Adjacent Areas
As noted in earlier sections, the Project Restoration and Enhancement Sites are located within
Summitridge Park, within parcels owned by the City of Diamond Bar. Public park trails run
adjacent to the sites with additional open space bounding the sites on all sides. No change in
adjacent land use is proposed.
Adjoining uses are predominately public open space and recreation, in addition to private
residential areas bounding Summitridge Park in all directions.
3.6 Reference Site(s)
A reference site location was reviewed, which is located approximately 0.3 mile southwest of
the Project Restoration Site. The reference site is situated along Canyon Loop Trail,
downslope of the trail improvement area (Refer to Figure 7, Reference Site Locations). The
reference site was utilized for defining the plant palette and provided information on density
of cactus stands, slope aspect, suitable topography, and functions and values.
The reference site is situated on a southerly to southeasterly facing slope, with gently sloping
topography. The local relief consists of a concave, shallow draw that extends downslope
toward the riparian zone located along the canyon floor. The reference site consists of CPPS.
Coast p rickly pear is dominant within this vegetation community, with sticky monkey flower
(Diplacus aurantiacus) prominently interspersed throughout the area. California buckwheat
and California sagebrush are also present, but in lower proportions compared to coast prickly
pear and sticky monkeyflower. Blue elderberry (Sambucus nigra ssp. caerulea) and southern
California black walnut (Juglans californica) are also present sporadically. Overall, the
approximate absolute cover of native species was found to be 60 percent coast prickly pear,
20 percent sticky monkey flower, and 10 percent California buckwheat, with 10 percent of
cover consisting of bare ground. Photographs of the CPPS reference site and its
corresponding location are provided in Figure 8, Reference Site Photographs.
A reference site location was reviewed, which is located approximately 0.01 mile west of
Project Enhancement Site B, and approximately 0.20 mile southwest of Site A. The reference
site is situated along the north side of Canyon Loop Trail (Refer to Figure 7, Reference Site
Locations). The reference site was utilized for defining the plant palette and provided
information on suitable topography and functions and values.
The reference site is situated on a gently sloped area above Canyon loop trail, facing north.
The Reference site consists of CSBSS. Black sage is dominant within this vegetation
community, with approximately 85 percent absolute cover. The remaining cover consisted of
California sagebrush at 10 percent absolute cover, and 5 percent consisted of non-native
Description of Proposed Restoration Site
Canyon Loop Trail Improvement Project
Habitat Mitigation and Monitoring Program 17
herbaceous species and bare ground. Photographs of the CSBSS reference site and its
corresponding location are provided in Figure 8, Reference Site Photographs.
!>
!>34.003596-117.80034
34.002102-117.801987
Reference Site Locations
Figure 7
°0 7537.5
Feet9/7/2022 JN C:\Users\ryan.phaneuf\OneDrive - Michael Baker International\Documents\GIS\178669 - Canyon Loop\GIS\MXD\HMMP\Fig 07 Reference Site Locations.mxd RPLegend
CPPS Reference Site
CSBSS R efe re nce Site
!>Refe re nce Po int
CANYON LOOP TRAIL IMPROVEMENT PROJECT
HABITAT MITIGATION AND MONITORING PROGRAM
Source: Nearm ap (05/2022)
CanyonLoopTrail
08/19/2022 JN 178669
PhotoPoint1 –Looking west into the CPPS reference site from Canyon Loop Trail.
CANYON LOOP TRAIL IMPROVEMENT PROJECT • HABITAT MITIGATION AND MONITORING PROGRAMFigure 8 - Reference Site Photographs
July 2022
PhotoPoint2 –Looking southwest into the CPPS reference site.
PhotoPoint3 –Looking south (downslope) into the CPPS reference site.PhotoPoint4 –Looking southeast into the CPPS reference site.
Canyon Loop Trail Improvement Project
Habitat Mitigation and Monitoring Program 20
Section 4 RESTORATION SITE
IMPLEMENTATION PROGRAM
4.1 Basis for Success
The Program is expected to be successful because: (1) the Project has been designed with
the appropriate topography and slope aspect known to support CPPS; (2) the plan t palette
selected includes a mixture of locally present CPPS and CSBSS species; (3) the Prog ram
allows for adaptive management and remedial action if necessary; and (4) the Project
Restoration Ecologist, knowledgeable in native plan t vegetation and local wildlife biology will
supervise the implementation, maintenance, and monitoring of the restoration .
4.2 Responsible Parties
Successful Program implementation will be the responsibility of the Project Proponent, the
City of Diamond Bar.
4.3 Financial Assurances
All costs associated with this Program are the responsibility of the City of Diamond Bar. Upon
successful completion of the Program and receipt of resource agency confirmation of Program
success, the City of Diamond Bar’s financial responsibilities will be fulfilled.
4.4 Implementation Schedule
The Project Restoration Ecologist shall supervise site preparation, installation of plant
materials, and maintenance. Initial site clearing implementation activities are anticipated to
occur in fall of 2023, following Project construction and implementation of the Canyon Loop
Trail improvement.
4.5 Contracting Requirements
Restoration requires the contracting and coordination of several entities early in the planning
phase of restoration, as follows:
1. Retain a Project Restoration Ecologist, who is familiar with both restoration,
enhancement, and local wildlife biology.
2. Contract with a native seed and plant supplier at least three months prior to planting
to determine availability of stock.
3. Retain a qualified Restoration Contractor with experience in cactus and California
sagebrush scrub habitat restoration projects for installation.
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Canyon Loop Trail Improvement Project
Habitat Mitigation and Monitoring Program 21
Planting and seeding at the Project Restoration and Enhancement Site s should occur after
the first rains and between October 1 and January 15 to take advantage of the winter rainy
season, high soil moisture, cooler temperatures, dormancy of foliage, and rooting period to
ensure optimum survival of plantings and to avoid nesting bird season (February 15 to August
31, or February 15 to September 15 for CAGN/CACW).
4.6 Site Construction, Preparation, and Monitoring
Construction acti vities (i.e., site preparation, habitat restoration) consist of: (1) minor clearing
and grubbing (2) weed abatement; and (3) planting and seeding. The Project Restoration
Ecologist will monitor construction activities as needed to confirm that these activities comply
with the avoidance, minimization, and mitigation measures designed to protect the sensitive
biological resources associated with the Project. The Restoration Contractor, under the
guidance of the Project Restoration Ecologist will have flexibility through the restoration and
enhancement process based on day -to-day site conditions to ensure the highest restoration
success.
4.6.1 Pre-Construction Meeting and Contractor Training Program
The Project Restoration Ecologist will attend all pre-construction meetings and discuss the
biological monitoring program with construction personnel. The contractor training program
will discuss the following:
• Sensitive biological resources present on-site, with emphasis on the CAGN and
CACW;
• Avoidance, minimization, and mitigation measures developed for the Project, with
emphasis on the measures outlined Coastal California Gnatcatcher Avoidance and
Minimization Strategy for the Canyon Loop Trail Improvement Project (Appendix B);
• Importance of adhering to these measures to avoid potential adverse impacts to these
sensitive resources; and
• Penalties associated with non-compliance.
4.6.2 Site Fencing and Buffer Flagging
Prior to construction activities, the Project Restoration Ecologist will supervise the placement
of orange construction fencing or equivalent along the limits of disturbance adjacent to
sensitive biological habitats and verify compliance with any other avoidance, minimization,
and mitigation measures. This will include flagging buffers to protect sensitive biological
resources (e.g., habitats, nesting birds, sensitive species) during construction.
Restoration Site Implementation Program
Canyon Loop Trail Improvement Project
Habitat Mitigation and Monitoring Program 22
4.6.3 Nesting Bird Clearance Surveys
To avoid potential adverse impacts to CAGN and CACW, construction activities should be
conducted outside of the breeding season for these species (February 15 through September
15). To avoid potential adverse impacts to other species covered by the Migratory Bird Treaty
Act (MBTA), construction activities should be conducted outside of the MBTA breeding
season (February 1 to August 31). If construction must occur during the breeding season:
• A nesting bird clearance survey shall be conducted within seven days prior to the start
of construction within a 500-foot buffer of the project site. The survey shall be
conducted by a qualified biologist with demonstrable experience identifying CAGN and
CACW nesting behavior and finding their nests, and who has been approved by the
USFWS to conduct a CAGN survey. If an active CAGN or CACW nest is found during
the survey, no project-related construction shall be allowed within 500 feet of an active
CAGN nest or 300 feet of an active CACW nest, or within an alternative safe distance
as determined by the qualified biologist based on topography, visual shielding, nest
progress, and the type of construction and associated disturbance, until the active nest
has been determined by the qualified biologist to have failed or to have successfully
gone to completion (i.e., the nestlings have fledged and are no longer reliant on the
nest). Results of the nesting bird clearance survey shall be compiled in a memorandum
and submitted to the City and the USFWS for project records.
4.6.4 Clearing and Grubbing
Vegetation removal will consist of removing and disposing of all non-native trees, bushes,
shrubs, stumps, roots and any other non-native material to accommodate the project
improvements as required to complete the work in place.
4.6.5 Weed Abatement prior to Planting and Seeding
Upon completion of the clearing and grubbing work and prior to planting and seeding, the
Restoration Contractor shall perform weed control measures. Exotic pest plant removal and
eradication of weedy plant species will be performed by hand pulling and weed whipping,
using herbicides, or by other methods approved by the agencies. The Project Restoration
Ecologist shall direct the Restoration Contractor regarding the selection of target weed
species, their location, and the timing of weed control operations to ensure that native plants
are avoided, if possible. Preservation of native plants within the Project Enhancement sites
during weed abatement will be paramount, as the existing native cover will allow for higher
probability of successful enhancement activities if left in place.
Restoration Site Implementation Program
Canyon Loop Trail Improvement Project
Habitat Mitigation and Monitoring Program 23
Due to the heavily invaded current state of the Project Restoration and Enhancement Site s, a
minimum of two rounds of weed abatement are proposed prior to native plant installation.
Hand pulling, weed whipping, and as-needed herbicide application shall occur following the
completion of any grubbing or clearing of woody non-native vegetation. The initial weed
abatement shall be followed by one complete growing season, to allow for emergence of
species from the non-native seedbank. Following the onset of the growing season but before
seed setting, a second round of weed abatement shall occur, following the same methodology
as the first round. If needed, a second full growing season, followed by a third round of weed
abatement may occur prior to native plant installation, at the discretion of the Project
Restoration Ecologist.
Removal of non-native vegetation and invasive species will be conducted under the direction
of the Project Restoration Ecologist, in accordance with existing project controls and
regulatory requirements. Non-native species requiring application of herbicide for removal are
not known to occur within the Project Restoration Site but have been documented in the
project vicinity. These species include:
• Australian saltbush (Atriplex semibaccata)
• pampas grass (Cortaderia jubata)
• sweet fennel (Foeniculum vulgare)
• scarlet pimpernel (Lysimachia arvensis)
• tree tobacco (Nicotiana glauca)
• castor bean (Ricinus communis)
• curly dock (Rumex crispus)
To apply an unrestricted herbicide (e.g., Roundup Custom), the Restoration Contractor must
have a Pest Control Business License, which requires that at least one individual employed
by the Restoration Contractor be in possession of a Qualified Applicator’s License (QAL). If a
QAL is not present during treatment, all applicators must have undergone documented
herbicide application training. All licenses must be issued by the State of California, be
registered in Los Angeles County, and be of current status. In aquatic situations, only a U.S.
Environmental Protection Agency (EPA) approved, glyphosate-based systemic herbicide
approved for aquatic use may be applied. No preemergent herbicides may be used.
Spraying shall be conducted only when weather conditions are conducive to effective uptake
of the herbicide by the targeted species (i.e., sunny, dry, when plants are actively growing)
and when wind conditions are such that herbicide drift is nonexistent. During herbicide
application, protection or avoidance of native species is required. Any native species lost
within the restoration areas due to intentional or unintentional application of herbicide shall be
replaced during the following planting season at the direction of the Project Restoration
Ecologist.
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Canyon Loop Trail Improvement Project
Habitat Mitigation and Monitoring Program 24
No herbicides shall be used on native vegetation. Prior to application of pesticide, the
Restoration Contractor shall coordinate with the Project Restoration Ecologist to discuss the
planned pesticide application and schedule biological monitoring, if needed. In addition, the
Restoration Contractor shall notify the City at least 24 hours prior to each application of
pesticide and shall indicate the hours of application. The Restoration Contractor will remove
off -site all exotic plant material in a legally acceptable manner to a location that prevents its
re-establishment.
4.6.6 Planting
At the time of installation, all plants of the same species and container size (i.e., the same
specification) shall be uniform in size and shape and at the same stage of growth to the
satisfaction of the Project Restoration Ecologist.
The Restoration Contractor shall be responsible for managing the site and performing
planting, maintenance, and corrective measures to the best advantage of the plant material
to promote healthy growth, establishment, and success of the plantings. This shall include
providing drainage , irrigation, maintaining a proper soil moisture level, weeding, fertilization,
protection, temporary measures to promote establishment, and other reasonable
maintenance and construction efforts needed to provide for the successful establishment of
the plant materials during the contract period.
4.7 Planting Plan
As noted above, native vegetation types typical within the Project vicinity will be established
within the Project Restoration and Enhancement Site s. The Restoration Contractor under the
direction of the Project Restoration Ecologist will install plantings in a configuration that mimics
natural conditions typical of CPPS. Coast prickly pear plant material will be collected from
existing stands of CPPS in Summitridge Park to the extent possible. Other plant material ,
including additional cactus plant material, as necessary, will be sourced from local nurseries
wherever possible. Container stock will be purchased from a reputable local native plant
nursery that uses seeds and plants collected locally to maintain the integrity of genotypes.
The spacing and layout of the plants will be typical to CPPS.
A native seed mix will be applied within the Project Enhancement Site following the conclusion
of the weed abatement period.
4.7.1 Plant and Seed Palet tes
The CPPS native plant pale tte will include plant species that occur in CPPS habitat s in the
vicinity of the Project Restoration Site. Table 4, below, lists the types and quantities of seed,
container, or collected stock to be installed within the Project Restoration Site.
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Canyon Loop Trail Improvement Project
Habitat Mitigation and Monitoring Program 25
Table 4: Coast Prickly Pear Scrub Plant and Seed Palette
Scientific Name Common Name Size or Type
of Planting
Lb/Acre
of Seed
Quantity of
Seed (lbs)
Quantity of
Container / Collected Stock
Container Plant Species
Opuntia littoralis Prickly pear 1 gallon &
cuttings 0 0 150 3
Rhus integrifolia Lemonade berry 1 gallon 0 0 5
Sambucus nigra ssp. caerulea Blue elderberry 1 gallon 0 0 5
Seeded Species
Acmispon glaber Deerweed seed 20.84 2.65 0
Diplacus aurantiacus Sticky monkey flower seed 1.00 0.13 0
Encelia californica Bush sunflower seed 13.60 1.73 0
Eriogonum fasciculatum California buckwheat seed 11.62 1.48 0
Melica imperfecta Coast range melic seed 10.89 1.39 0
Mirabilis laevis var. crassifolia Wishbone plant seed 31.11 3.95 0
Salvia apiana White sage seed 13.92 1.77 0
Salvia mellifera Black sage seed 6.33 0.81 0
Stipa lepida Foothill needle grass seed 7.99 1.02 0
Total 117.30* 14.93* 160
*Totals may not sum due to rounding.
The CSBSS native seed palette will include plant species that occur in CSBSS habitat s in the
vicinity of the Project Restoration Site. Table 5, below, lists the types and quantities of seed
to be installed within the Project Enhancement Site.
Table 5: California Sagebrush – Black Sage Scrub Seed Palette
Scientific Name Common Name Size or Type of
Planting Lb/Acre of Seed Quantity of Seed
(lbs)
Seeded Species
Acmispon glaber Deerweed seed 20.84 2.93
Artemisia californica California sagebrush seed 1.02 0.14
Diplacus aurantiacus Sticky monkey flower seed 1.00 0.14
Encelia californica Bush sunflower seed 13.60 1.92
Eriogonum fasciculatum California buckwheat seed 11.62 1.63
Malosma laurina Laurel sumac seed 17.85 2.51
Rhus integrifolia Lemonade berry seed 26.01 3.66
Salvia apiana White sage seed 10.44 1.47
Salvia mellifera Black sage seed 8.44 1.19
3 Relative q uantities of prickly pear cuttings and 1 gallon container stock will be determined at the time of planting.
The Restoration Contractor, under the direction of the Project Restoration Ecologist, will select healthy, robust
cactus plant material suitable for harvesting cuttings if suitable mater ial is available in Summitridge Park. The
amount of material available for harvesting cuttings will be highly dependent on conditions at the time of the
harvesting . If minimal or no suitable cactus cutting material is available, the Restoration Contractor shall purchase
and install 1-gallon prickly pear container stock to make up the difference in planting deficiencies.
Restoration Site Implementation Program
Canyon Loop Trail Improvement Project
Habitat Mitigation and Monitoring Program 26
Scientific Name Common Name Size or Type of Planting Lb/Acre of Seed Quantity of Seed (lbs)
Stipa lepida Foothill needle grass seed 7.99 1.13
Stipa pulchra Purple needle grass seed 8.14 1.15
Total 126.95* 17.87*
*Totals may not sum due to rounding.
4.7.2 Seed Installation
The native seed mix will be hand broadcasted in the Project Restoration and Enhancement
Site s in the fall or winter months (approximately October through January) to take advantage
of the cooler weather and natural rainfall. The timing of seed dispersal to optimize the rainy
season shall be under the discretion of the Project Restoration Ecologist. Seed will be hand
broadcasted into the Project Restoration and Enhancement Site s following exotic species
removal and thoroughly raked to ensure contact with the soil. The ground should be
thoroughly wet prior to seeding. Seed should be spread following rainfall events to ensure
direct contact with moist soils to aid in germination of species.
4.7.3 Planting Container Stock
The Project Restoration Ecologist must be on-site to identify planting locations and ensure
that plantings are installed in a natural pattern, not in rows. In addition, the hand broadcast
seed mix will be applied before planting occurs. The following planting descriptions are
intended for container stock plant species. A separate description of the installation process
for preparation and planting of prickly pear cactus pad cuttings is provided below in Section
4.7.4.
All appropriate container-grown plan ts shall be inoculated with mycorrhizal fungi prior to
delivery to the Project Restoration Site. Mycorrhizae are symbiotic fungi found on plan t roots
that enable plan ts to take up nutrients and withstand drought more effectively. Plan ts
inoculated with mycorrhizal fungi increases the success of the revegetation effort in disturbed
or degraded soils. The mycorrhizal inoculum shall include endomycorrhizal fungi (AM‐80) with
a minimum count of 60 million propagules per pound. This inoculum shall be less than 2 years
old, as demonstrated by the manufacturer. Inoculum is sold as loose granules or as liquid and
shall be used with the application of the hydroseed slurry mix prior to or during planting and
seeding.
All container stock shall be soaked the day before plan ting. The containers must be upended
into the palm of the hand to avoid damage to the root ball and gently placed in the plan ting
hole. Finally, the plan ting hole must be backfilled with native soil.
After plan ting, a three-inch high, hand-compacted earth berm shall be constructed around
each container plan t and maintained until the plan ts are no longer irrigated. All installed
Restoration Site Implementation Program
Canyon Loop Trail Improvement Project
Habitat Mitigation and Monitoring Program 27
container stock must be thoroughly watered immediately after installation. If recommended by
the Project Restoration Ecologist, coarse mulch may be necessary around the plan tings to
minimize water loss and discourage weed growth. Mulch shall be applied 3 to 4 inches deep
and cover an area of at least 1.5 times the diameter of the dripline of the plan t or 2 feet in
diameter, whichever is greater, but not placed directly against the main stem of the plan ts.
Wood mulch shall be free of deleterious materials, including any invasive species, and suitable
as a top dressing for trees and shrubs and in the seed mix.
4.7.4 Cactus Pad Cuttings
The following prickly pear cactus pad collection protocol has been adapted from the
methodology described in the Irvine Ranch Conservancy’s 2011 report on the results of post-
burn restoration of nesting habitat for the Coastal Cactus Wren within the Orange County
Central Reserve (Irvine Ranch Conservancy 2011). The collection protocol shall generally be
as follows:
• Collection shall be restricted to existing cactus stands within Summitridge Park.
• Collection shall be restricted to non-breeding season of CACW.
• Collection of pads is not to exceed five percent of any given square meter of cactus
(equal to approximately seven pads per square meter)
• Collection shall be restricted to sites with the lowest density of CACW in the region
(either no individuals or a single pair within the larger collection area)
• Collection shall not take place from plants less than one square meter.
• Collection shall not take place from a plant less than two thirds green.
• Collection shall not include pads less than fourteen by seven centimeters;
• And, collection shall not include pads removed from the top of the plant, with
preference given to stray pads and basal branches.
Prickly pear cactus can be collected at any time of the year, but survivorship of harvested
cactus is generally higher during times of the year that plants are not subject to drought stress
(Dodero 2008). Drought stress can become most apparent during the fall season, when plants
have often gone an entire summer with minimal moisture. Signs of drought stress include
wrinkled or shriveled pads, indicating a deficit of stored water. Water uptake begins quickly
following sufficient rains, resulting in a loss of their wrinkled appearance. To allow for the best
possible chance of survivorship, cactus pads should be collected when cactus are healthy
and robust, with mature pads. If possible, cactus pads should be harvested following the first
significant winter rains, when sufficient water uptake has occurred, and before young,
emerging shoots have begun to grow in the spring. Cactus for harvest shall be selected at the
discretion of the Restoration Contractor, with guidance from the Project Restoration Ecologist.
Cactus pads should be handled carefully, avoiding direct, by-hand contact when possible.
Tools such as tongs, pitchforks, and buckets may be used to handle and transport cactus
Restoration Site Implementation Program
Canyon Loop Trail Improvement Project
Habitat Mitigation and Monitoring Program 28
pads to avoid contact with cactus spines. Following harvesting, the broken or cut ends of the
cactus stem should be allowed to dry and harden for 3-4 weeks prior to installation. Cactus
pads may be laid out at the Project Restoration Site in contact with the soil and allowed to
callus on site. Plantings may alternatively be laid out on shade cloth in the sun or placed in
containers such as 1-gallon pots or plastic bins and stored off -site and allowed to callus for
the appropriate period, before transporting back to the Project Restoration Site for installation.
Cactus pads should be monitored frequently during the callousing process, as pads may begin
to send roots toward the ground if they are left too long.
Once cactus pads have sufficiently callused, they should be planted on their sides, in shallow
holes or trenches to a depth of approximately one-third of the height of the pad (Irvine Ranch
Conservancy 2011). Cactus pad plantings should be watered following installation. Taller
native shrubs, such as blue elderberry or lemonade berry can be placed adjacent to or within
cactus patches to provide structure as the patch matures. One gallon cactus container stock
may also be placed within each patch to provide immediate vertical structure and supplement
cactus pad planting numbers. Depending on the availability of cactus for collection, planting
quantities may shift to 1 gallon container stock as the primary or sole cactus stock installed.
4.8 Irrigation Plan
When natural hydrology is inadequate to ensure survival of installed plantings, supplementary
irrigation must be provided. Supplementary irrigation shall be provided as needed for a
minimum of t hree years after installation of the plants and seed mix. Irrigation shall then be
phased out during the fall/winter of the third year unless severe conditions threaten survival
of the plantings. By -hand irrigation is proposed for the Restoration and Enhancement Project
Sites. Water barrels, tanks , or water buffalo trailers may be stored on-site or may be
transported on-site during maintenance activities. All planted stock must survive and grow for
at least two years without supplemental water for the Project Restoration Site to be eligible for
sign-off.
Prickly pear cactus plantings should not be placed on a regular watering schedule, as too
frequent of watering may cause root rotting. Soils around cactus plantings should be allowed
to dry fully between watering events. Watering frequency for cactus plantings shall be
determined by the Restoration Contractor. Other container plantings (blue elderberry and
lemonade berry) should be placed on a regular by-hand watering schedule for the first three
years following installation.
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Canyon Loop Trail Improvement Project
Habitat Mitigation and Monitoring Program 29
4.9 Signage
Appropriate signage must be placed by the Restoration Contractor at regular intervals around
the perimeter of the Project Restoration Site to restrict access. Signs must also be labeled in
Spanish, Korean, Mandarin, and Cantonese. The signs must be greater than 1 ft by 1 ft. The
signs must say something similar to:
4.10 As-Built Conditions
Once the restoration has been implemented, the Project Restoration Ecologist will submit a
report to the resource agencies within 30 days of completion of the 90-day plan t establishment
period for the restoration plans. The report will include a topographic map showing any
adjusted contours of the restoration areas and the as-built locations of the plan tings. The
report will also be inclusive of the Year 0 baseline data. At this point, the agencies may request
a site visit to ensure that the restoration has been implemented correctly.
DO NOT ENTER
RESTORATION IN PROGRESS
Canyon Loop Trail Improvement Project
Habitat Mitigation and Monitoring Program 30
Section 5 MAINTENANCE ACTIVITIES
DURING THE MONITORING
PERIOD
The maintenance activities described in this section will be performed within the Project
Restoration and Enhancement Site s throughout the five-year monitoring period. Biological
resources will be protected at all times during all maintenance activities. The Project
Restoration Ecologist will monitor all aspects of the restoration plan in an effort to detect any
problems at an early stage. Potential problems could arise from unforeseen changes in
hydrology, erosion, vandalism, competition from weeds and invasive species, or unacceptable
levels of disease and pests. After the five-year monitoring period, the City will assume
responsibility for long-term maintenance of the restoration plan tings.
5.1 Maintenance Activities
5.1.1 Plant Inspection
Af ter installation, the Project Restoration Ecologist and restoration contractor will conduct
monthly qualitative monitoring of the Project Restoration and Enhancement Site s for the first
18 months following the initiation of the monitoring and maintenance period. Qualitative
monitoring will continue every other month for the last six months of the second year, unless
otherwise recommended by the Project Restoration Ecologist. Qualitative monitoring may be
reduced to once quarterly for the rest of the five-year habitat restoration monitoring period or
as recommended by the Project Restoration Ecologist. The Project Restoration Ecologist will
maintain a written record of each site visit that will be provided to the City quarterly by email.
Documented observations will include plan t health and issues (e.g., vandalism, weeding,
irrigation scheduling, debris removal). Quantitative analysis will occur separately from the
qualitative assessments.
5.1.2 Removal of Exotic Plant Species
During the five-year monitoring period, the Project Restoration and Enhancement Site s will
be maintai ned by the Restoration Contractor to minimize weed cover during the monitoring
period. Removal methods other than manual weeding must be approved by the Project
Restoration Ecologist. Only EPA-approved herbicides will be used within the Project
Restoration and Enhancement Site s. Throughout the Project Restoration and Enhancement
Site s, areas must be maintained free of perennial exotic plan t species including, but not limited
to, black mustard, short podded mustard, and castor bean. Weed eradication is imperative to
suppress competition that could prevent establishment of the restoration plan tings and seed
mix . The Restoration Contractor must be prepared to respond to weed control needs rapidly,
and the Project Restoration Ecologist must provide adequate supervision for maintenance
Maintenance Activities During the Monitoring Period
Canyon Loop Trail Improvement Project
Habitat Mitigation and Monitoring Program 31
personnel that may not be skilled at identifying and discriminating between weeds and native
species. Weed debris shall be removed from the Project area and disposed of as permitted
by law. Pulled weeds shall be placed on a tarp to prevent the seeds from touching the ground.
5.1.3 Replacement of Native Plant Species
If significant quantities of restoration plan tings decline in health or exhibit mortality, they must
be replaced. The Project Restoration Ecologist will coordinate with the City and the
Restoration Contractor for implementation. Areas where loss of container stock has occurred
will be replaced as needed between October 1 and February 15 to take advantage of the
winter rainy season. These areas must be revegetated with the same native species being
replaced. Replacement of container stock will be conducted following the same procedures
as used during installation.
If low seed mix establishment is noted by Year 2, the Restoration Contractor must re-seed
with the same native species as were included in the original seed mix, following the same
procedures as used during installation. However, alterations to the seed mix may be
implemented at the discretion of the Project Restoration ecologist, should they be necessary
to promote improved establishment or species diversity within the Project Restoration and
Enhancement Sites.
5.1.4 Trash and Debris Removal
During routine maintenance, the Restoration Contractor must remove litter, trash, and debris,
including removed non-native vegetation, from the Project Restoration Site and dispose of it
off -site as permitted by law. The Restoration Contractor is responsible for avoiding impacts to
plan tings during trash removal activities.
5.1.5 Irrigation Frequency
The City will be responsible for supplying sufficient irrigation water to adequately establish
new plan t materials , or for reimbursing the Restoration Contractor for water costs should the
Contractor establish their own connection to a municipal water source. Temporary irrigation
will be implemented in the form of water tanks, barrels, or water buffalo trailers stored onsite
or transported on and off site as needed. Prior to final sign-off and release of securities, all
irrigation components shall be removed from Project site.
Irrigation will be periodic and deep to encourage deep root growth. Irrigation must be applied
infrequently enough to allow soil to dry in the top six to ten inches. Wetting of the full root zone
and drying of the soil between irrigation events is essential to promoting deep root growth that
will support the vegetation once it is established. Irrigation frequency will be overseen by the
Restoration Contractor and Project Restoration Ecologist, and will follow guidelines
appropriate to native species, and adjusted as needed for climate.
Maintenance Activities During the Monitoring Period
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Habitat Mitigation and Monitoring Program 32
5.2 Responsible Parties
Maintenance activities will be the responsibility of the Restoration Contractor appointed by the
City.
5.3 Maintenance Schedule
The Restoration Contractor will conduct monthly maintenance of the site for at least the first
two years. Maintenance frequency may be reduced to every two months for the third and
fourth years and may be reduced further to once every quarter if recommended by the Project
Restoration Ecologist. The maintenance schedule will be adjusted as needed, based on
monitoring results. A preliminary schedule can be found within Table 6, below.
Table 6: Maintenance Schedule
Year of
Maintenance
Jan Feb March April May June July Aug Sept Oct Nov Dec
1 X X X X X X X X X X X X
2 X X X X X X X X X X X X
3 X X X X X X
4 X X X X X X
5 X X X X
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Habitat Mitigation and Monitoring Program 33
Section 6 MONITORING PROGRAM AND
DOCUMENTATION
Monitoring will be performed by the Project Restoration Ecologist to facilitate compliance with
the success criteria set forth in this section.
6.1 Performance Standards, T arget Dates, and Success Criteria
Performance criteria used to evaluate success of the Project Restoration Site include percent
survival and percent cover. Success will be based on achieving specific target levels at the
end of each year as summarized in Table 7, below.
Table 7: CPPS Restoration Performance Standards
Year
Percent Survival
by Planted
Species
Percent Cover by
Native Species
Percent Cover by
Non-Native
Species
Percent Bare
Ground
1 80% NA NA < 5 0%
2 80% NA NA < 25%
3 80% 75% NA < 15%
4 80% 75% NA < 15%
5 80% 90% < 5% < 15%
Performance criteria used to evaluate success of the Project Enhancement Site include
percent cover. Success will be based on achieving specific target levels at the end of each
year as summarized in Table 8, below.
Table 8: CSBSS Enhancement Performance Standards
Year Percent Cover by Native
Species
Percent Cover by Non-
Native Species Percent Bare Ground
1 NA NA < 50%
2 NA NA < 25%
3 75% NA < 15%
4 75% NA < 15%
5 90% < 5% < 15%
At the first and second anniversary of plant installation, all dead plants will be replaced unless
their function has been replaced by plants from seed or natural recruitment. In addition to
Canyon Loop Trail Improvement Project
Habitat Mitigation and Monitoring Program 34
percent survival and percent cover, the restoration success criteria for the restoration area will
include evidence of natural recruitment of multiple species for all habitat types, 0 percent
coverage for all woody California Invasive Plant Council’s (Cal-IPC’s) “Invasive Plant
Inventory” species (e.g., trees and shrubs), and no more than 10 percent coverage for other
exotic/weed species. Species and structural diversity should be similar to the reference site
location. The sampling design to be employed is included below.
6.2 Target Functions and Values
The target habitat types to be restored and enhanced are CPPS and CSBSS. Various
functions and values, such as increased cover and diversity of native plant species, increased
connection between native habitats, decreased connectivity between non-native plant
dominated areas, and increased habitat value and acreage for key wildlife species are
anticipated to result from the restoration and enhancement.
6.3 Monitoring Methods
6.3.1 Qualitative Monitoring
Monitoring of the Project Restoration and Enhancement Site s must utilize a quantitative
functional-based assessment to establish baseline conditions, set success criteria, and
assess restoration site progress. Qualitative surveys will be performed by the Project
Restoration Ecologist and will consist of a general site-walk. General observations, such as
fitness and health of the plan ted species, pest problems, weed establishment, mortality, and
drought stress, will be noted in each site visit. The Project Restoration Ecologist will also note
observations on wildlife use and native p lan t recruitment for the purpose of later discussion in
the annual monitoring memos. Records will be kept of mortality and other problems such as
insect damage, weed infestation, and soil loss. The Project Restoration Ecologist will
determine remedial measures necessary to facilitate compliance with performance standards.
All remedial measures undertaken will be referenced in the annual monitoring memos to the
City.
6.3.2 Quantitative Monitoring
An annual quantitative monitoring visit will be conducted by the Project Restoration Ecologist
to determine whether the site has met the performance criteria for the year. During the
quantitative monitoring event, the Project Restoration Ecologist will determine the percent-
survival of the plan tings and the vegetative cover of native and non-native species on the site.
If the survival and cover requirements have not been met, the City is responsible for
replacement plan tings to achieve the requirements. Monitoring will assess the attainment of
annual and final success criteria and identify the need to implement contingency measures in
the event of not meeting success criteria.
Monitoring Program and Documentation
Canyon Loop Trail Improvement Project
Habitat Mitigation and Monitoring Program 35
Quantitative monitoring for percent-survival is conducted through an annual census of all
container stock installed. The number of missing, dead and/or declining plan t stock will be
recorded for each plan t species installed within the Project Restoration Site. The percentage
of surviving container stock will then be calculated. No percent survival count will be performed
for the Project Enhancement Site, as no container stock will be installed as part of the
enhancement activities.
Percent cover will be measured using the relevé monitoring technique. Relevé monitoring is
proposed as the preferred methodology for monitoring CPPS and CSBSS because it allows
the monitor to assess vegetation conditions primarily from the margin of the habitat, allowing
for avoidance of damage to cactus plants or injury to monitors from contact with cactus, as
well as avoiding damage to existing native vegetation in the Enhancement Project Sites.
Utilizing relevé instead of standard transect monitoring methodology will result in preservation
of the health of the cactus scrub, and continued establishment of seed mix and recruit species
with minimal disturbance throughout the monitoring period. It will also allow for improved
avoidance of wildlife species such as CACW or CAGN should they be present in the Project
Restoration or enhancement Site s during the monitoring period.
The CNPS relevé method is an ocular estimation technique used to classify and map large
areas in a limited amount of time A stand, or homogenous unit of vegetation that generally
has compositional and structural integrity is sampled by representative plots. The sampler
defines the vegetation layers present and all plant species within each layer, assigning a
percent cover number to each species documented. Absolute or relative percent cover can
then be calculated from the results. The Project Restoration Site will be surveyed with one
relevé plot of approximately the CNPS recommended minimum area for shrublands (400
meters2). Plant layers and individual species cover estimates will be recorded within the plot.
Both Project Enhancement sites will be assessed separately with one relevé plot defined for
each site.
Photo-documentation will be conducted from permanent photo-stations established prior to or
during the first annual monitoring event. Photos will be taken during each monitoring visit and
from the same vantage point and in the same direction every year. An exhibit will be included
with the annual monitoring memos to show the locations of each photo station.
6.4 Monitoring Schedule
Qualitative monitoring will be conducted monthly for the first 18 months and will begin
immediately after completion of plant installation. Qualitative monitoring will continue every
other month for the last six months of the second year, unless otherwise recommended by
the Project Restoration Ecologist. Qualitative monitoring may be reduced to once quarterly for
the rest of the five-year monitoring period or as recommended by the Project Restoration
Ecologist.
Monitoring Program and Documentation
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Habitat Mitigation and Monitoring Program 36
The first quantitative annual monitoring will occur the first June following the first growing
season after installation and every year thereafter until all five-year performance standards
are met, and the CDFW and City have confirmed success of the restoration .
6.5 Annual Monitoring Reports
The Project Restoration Ecologist will prepare and submit annual summary memos that
summarize site conditions to the City at the end of each year following initial implementation.
Summary memos will include a brief synopsis of the restoration and enhancement activities
accomplished during the year, a brief description of the conditions of the Project Restoration
and Enhancement Sites, a summary of the quantitative monitoring results, and
recommendations for adaptive management, as necessary. Summary memos will be
submitted to the City following the annual spring-summer survey. The spring-summer survey
must occur during optimal growing conditions between March and August, and the memos
will be submitted no later than December 31. A final monitoring report shall be submitted to
the City and CDFW following the completion of the Year 5 annual quantitative monitoring. The
final Year 5 monitoring report will be submitted no later than December 31. The final Year 5
monitoring report shall include, but is not limited to, the following:
• Title pages identifying the period for which the monitoring report is applicable;
• A list of names, titles, qualifications, and companies of all persons who prepared the
content of the annual report and participated in monitoring activities;
• Date of initiation of mitigation installation and date mitigation installation was
completed;
• Dates of any recent corrective or maintenance activities conducted since the previous
report submission;
• Specific recommendations for any additional corrective or remedial actions;
• Monitoring requirements and performance standards;
• A description of the restoration and enhancement activities conducted during the
previous year, including: site preparation, plant installation and overview of the
planting effort, the number by species of plants replaced or naturally recruited, and
when the activities were conducted, as appropriate;
• Current site conditions, including: percent cover, and the methods used to assess
these parameters;
• Information regarding non-native plant removal, including: the methods used for
removal, the amount removed and/or treated, the frequency and timing of removal and
treatment, disposal specifics, and a summary of the general successes and failures;
• Wildlife species observed at the creation site during monitoring surveys including
sensitive species and/or listed species; and,
Monitoring Program and Documentation
Canyon Loop Trail Improvement Project
Habitat Mitigation and Monitoring Program 37
• Photographs from designated reference points.
6.6 Preservation Mechanism
Once the performance standards for the compensatory mitigation site have been determined
to have been met by CDFW, the City will protect and manage the mitigation area in perpetuity,
with necessary funding provided by the City. Perpetual conservation will be assured through
the City of Diamond Bar’s General Plan designation of Open Space, which is inclusive of the
Project Restoration and Enhancement Sites. The Resource Conservation Element of the
General Plan includes Policy RC-P-3, which requires a vote of the people to remove the Open
Space designation from any piece of land. Policy RC-P-3 is stated below.
RC-P-3 A decision to rescind, terminate, abandon, remove, or modify an open space deed
restriction, map restriction or Open Space land use designation must be preceded by both a
finding by the City Council that the decision convers a significant benefit on the City and a
favorable vote of the electorate at a regular or special election.
In addition, a deed restriction has been placed over the Summitridge Park and trail system,
which was recorded as part of the requirements for receiving Safe, Clean Neighborhood
Parks, Open Space, Beaches, Rivers Protection, and Water Conservation Measure (Measure
A) Grant funding from the Los Angeles County Regional Park and Open Space District
(RPOSD). The deed restriction prohibits any uses of the property that are contrary to the
provisions of the Measure A Grant Agreement. The deed restriction is placed over the property
in perpetuity, and removal requires approval of both the City of Diamond Bar and the County
of Los Angeles.
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Habitat Mitigation and Monitoring Program 38
Section 7 COMPLETION OF RESTORATION
7.1 Notification of Completion
The City will notify the CDFW in writing when the five-year monitoring period is complete
and/or the success criteria have been met.
If the Project Restoration and Enhancement Site s meet all success criteria at the end of the
five-year monitoring period, the restoration and enhancement will be considered a success. If
not, the Program will be extended one full year at a time, and a specific set of remedial
measures approved by the CDFW will be implemented until the standards are met. Only those
areas that fail to meet the success criteria will require additional monitoring. This process will
continue until all the Year 5 performance criteria are met or until the CDFW determine that a
restoration alternative is appropriate. If at any time during the implementation and
establishment of the restoration or enhancement areas, and prior to verification of meeting
success criteria, a catastrophic natural event (e.g., fire, flood) occurs and impacts the
restoration or enhancement areas, the City is responsible for repair and replan ting of the
damaged area(s).
The final success criteria will be considered to have been met only after two years without
irrigation have elapsed and the Project Restoration and Enhancement Site s continue to
survive.
7.2 Agency Confirmation
Following receipt of the final Year 5 monitoring report, the City will contact the CDFW as soon
as possible to schedule a site visit, if needed, to confirm the completion of the restoration
effort. The restoration requirement will not be deemed complete until the City has received
written concurrence from the CDFW that the restoration project has met the restoration goals
and final performance criteria. A site visit from the resource agencies may be necessary prior
to obtaining written notification of completion from the CDFW.
7.3 Long-Term Maintenance
Long-term maintenance of the restoration and enhancement areas will be performed by the
City to continually preserve the habitat. Maintenance activities will occur as needed and will
include the removal of non-native vegetation and trash and debris, following guidelines stated
in Section 5 of this document. The maintenance of the project restoration and enhancement
sites will be encompassed in the City’s overall efforts to maintain the resources of Summitridge
Park.
Canyon Loop Trail Improvement Project
Habitat Mitigation and Monitoring Program 39
Section 8 CONTINGENCY MEASURES
8.1 Initiating Procedures
If it is determined that the Project Restoration and enhancement Site s will not meet the
success criteria at Year 5 , appropriate contingency measures will be performed if determined
necessary by the appropriate resource agency(ies) and as recommended by the Project
Restoration Ecologist to return the sites to compliance. Contingency measures will be based
on an adaptive management approach and will include: reseeding and rep lan ting with
quantities of appropriate species, additional weed control, and/or implementation of erosion
control and stabilization measures. If the Project Restoration and Enhancement Site s have
not met one or more of the performance criteria, the responsible party’s maintenance and
monitoring obligations shall continue one year at a time until the appropriate resource
agency(ies) give final approval that the restoration obligations have been satisfied.
8.2 Alternative Locations for Contingency Restoration
Sufficient area and appropriate rationale are provided for implementation on-site; therefore,
alternative locations should be unnecessary . Should alternative locations for restoration or
enhancement be required, the site will be located within the Summitridge Park area, the
Summitridge Trail system, or other area of open space within the City of Diamond Bar, and a
new restoration strategy may need to be developed in accordance with the CDFW.
8.3 Funding Mechanism
The Project Proponent, the City of Diamond Bar, will fund plan ning, implementation,
maintenance, and monitoring of any contingency measures that may be required to achieve
restoration goals.
8.4 Responsible Parties
The Project Proponent, the City of Diamond Bar, will be responsible for implementing,
maintaining, and monitoring any contingency procedures.
References
Canyon Loop Trail Improvement Project
Habitat Mitigation and Monitoring Program 40
Section 9 REFERENCES
California Department of Fish and Wildlife (CDFW). 2021. California Natural Community List.
Last updated August 18, 2021.
City of Diamond Bar. 2019. Diamond Bar General Plan 2040, Chapter 5 – Resource
Conservation. December 17, 2019.
Dodero, Mark. Guidelines for Cactus Salvage and Propagation. October 20, 2008.
Hamilton, Robert A. 2009. Restoration Guidelines for “Coastal” Cactus Wrens. May 14, 2009.
Michael Baker International. 2020. Results of Coastal California Gnatcatcher and Cactus
Wren Focused Surveys for the Canyon Loop Trail Improvement Project in the City of
Diamond Bar, Los Angeles County, California. August 7, 2020.
Rea, A. M. and K. Weaver. 1990. The taxonomy, distribution, and status of coastal California
Cactus Wrens. Western Birds 21: 81-126
The Irvine Ranch Conservancy. 2011. Post-Burn Restoration of Nesting Habitat for the
Coastal Cactus Wren in the Orange County Central Reserve: Final Report. March 30,
2011.
Appendix A CDFW Comments on Canyon
Loop Trail Improvement Project
State of California – Natural Resources Agency GAVIN NEWSOM, Governor
DEPARTMENT OF FISH AND WILDLIFE CHARLTON H. BONHAM, Director
South Coast Region
3883 Ruffin Road
San Diego, CA 92123
(858) 467-4201
www.wildlife.ca.gov
November 13, 2020
Mr. Ryan Wright
City of Diamond Bar
21810 Copley Drive
Diamond Bar, CA 91765
RWright@DiamondBarCA.gov
Subject: Mitigated Negative Declaration for the Canyon Loop Trail Improvement
Project, City of Diamond Bar, Los Angeles County
Dear Mr. Wright:
The California Department of Fish and Wildlife (CDFW ) has reviewed the above-referenced
Mitigated Negative Declaration (MND) for the Canyon Loop Trail Improvement Project (Project).
Thank you for the opportunity to provide comments and recommendations regarding those
activities involved in the Project that may affect California fish and wildlife. Likewise, we
appreciate the opportunity to provide comments regarding those aspects of the Project that
CDFW, by law, may be required to carry out or approve through the exercise of its own
regulatory authority under the Fish and Game Code.
CDFW’s Role
CDFW is California’s Trustee Agency for fish and wildlife resources and holds those resources
in trust by statute for all the people of the State [Fish & Game Code, §§ 711.7, subdivision (a) &
1802; Public Resources Code, § 21070; California Environmental Quality Act (CEQA)
Guidelines, § 15386, subdivision (a)]. CDFW, in its trustee capacity, has jurisdiction over the
conservation, protection, and management of fish, wildlife, native plants, and habitat necessary
for biologically sustainable populations of those species (Id., § 1802). Similarly, for purposes of
CEQA, CDFW is charged by law to provide, as available, biological expertise during public
agency environmental review efforts, focusing specifically on projects and related activities that
have the potential to adversely affect state fish and wildlife resources.
CDFW is also submitting comments as a Responsible Agency under CEQA (Public Resources
Code, § 21069; CEQA Guidelines, § 15381). CDFW expects that it may need to exercise
regulatory authority as provided by the Fish and Game Code, including lake and streambed
alteration regulatory authority (Fish & Game Code, § 1600 et seq.). Likewise, to the extent
implementation of the Project as proposed may result in “take”, as defined by State law, of any
species protected under the California Endangered Species Act (CESA) (Fish & Game Code, §
2050 et seq.), or state-listed rare plant pursuant to the Native Plant Protection Act (NPPA; Fish
& Game Code, §1900 et seq.), CDFW recommends the Project proponent obtain appropriate
authorization under the Fish and Game Code.
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Project Description and Summary
Objective: The City of Diamond Bar’s Parks and Recreational Department (City) proposes
several trail improvement features along the approximately 1.29-mile Canyon Loop Trail within
the Summitridge Park Trail system in Diamond Bar. Over the course of four months, the
following Project components are planned:
The existing trail along most of the South Canyon Loop would be widened to
approximately five feet and remain a natural, unpaved surface. The southern portion of
the Canyon Loop trail is roughly 1,942 feet. This Project proposes widening that
segment by 1-2 feet from its current width;
Gabion retaining walls would be provided in five areas along the South Canyon Loop to
stabilize soils and reduce erosion;
Stairs with handrails and cobblestone swales would be provided in six areas along the
South Canyon Loop to facilitate ease of access and safety and improve drainage;
Six drainage crossings are proposed along the South Canyon Loop;
Two shade structures with benches and trash receptacles would be provided along the
South Canyon Loop and one shade structure with benches and trash receptacles would
be provided along the North Canyon Loop at identified view points;
Lodge pole fences with “Trail Closed” signs mounted on the fences would be installed in
five areas along the South Canyon Loop to restrict trail users from entering informal trail
areas off the existing Canyon Loop trail;
A perforated bench is proposed on the west end of the South Canyon Loop;
A wayfinding sign would be installed on the eastern and western end of the Canyon
Loop Trail;
Interpretive signage in various locations that promote awareness of the presence of
sensitive biological habitat and species (including the coastal California gnatcatcher and
cactus wren), and indicate that the trail was implemented in a manner to minimize
impacts to biological resources; and
Long-term, routine maintenance of the project components above.
Location: The Project site is the existing Canyon Loop Trail, which is part of the Summitridge
Park Trail System. Summitridge Park is bounded by residential developments to the east and
west, Grand Ave. to the south, and open space to the north. It is situated within the central
portion of the City of Diamond Bar, Los Angeles County. Assessor’s Parcel Numbers (APNs)
associated with the Project are: 8701-059-904.
Comments and Recommendations
CDFW offers the comments and recommendations below to assist the City in adequately
identifying, avoiding and/or mitigating the Project’s significant, or potentially significant, direct
and indirect impacts on fish and wildlife (biological) resources.
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City of Diamond Bar
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Project Description and Related Impact Shortcoming
Comment #1: Impacts from increased trail usage
Issue: The Project is being proposed as a result of increased hiking traffic on the Summitridge
Trail System. With improved facilities and a widened trail, capacity is expected to increase.
Specific Impacts: Project activities, such as trail widening and the installation of benches or
shade structures, are likely to accommodate (and subsequently lead to) increased hiker
frequency and duration on the Canyon Loop Trail.
Why impacts would occur: Elevated hiker usage is likely to create direct and indirect impacts
to local wildlife species through the loss of potential habitat. An increase in the number of hikers
has potential to impact sensitive wildlife species and their habitat through a variety of ways:
increased numbers of people and dogs using the trail system
loss of habitat due to erosion from footpaths
increased noise levels
increased trash or pet waste
introduction of unnatural food sources via trash and trash receptacles
introduction of invasive species from other sites
The area of influence that the trail has upon the surrounding habitat is being increased.
Evidence impacts would be significant: Outdoor recreation has the potential to disturb
wildlife, resulting in energetic costs, impacts to animals’ behavior and fitness, and avoidance of
otherwise suitable habitat. Studies have shown that outdoor recreation is the second leading
cause of the decline of federally threatened and endangered species on public lands (Losos et
al. 1995), and fourth leading cause on all lands (Czech et al. 2000). As a result, natural resource
managers are becoming increasingly concerned about impacts of recreation on wildlife (Knight
and Gutzwiller 1995).
Recreational trails can fragment the habitat that they pass through. Clearing additional
vegetation to widen a thin (0.5-2 m) trail may have further negative impacts on wildlife (Holmes
2005). These negative impacts generally result from the expansion of the area of influence that
a trail has on its surrounding open space. Trails can create artificial boundaries or areas of
avoidance for wildlife as they bring outsiders into areas that would otherwise be unvisited. Along
with these perceived outsiders, in this case hikers, comes a new set of perceived threats to local
wildlife in the form of visual, auditory, and olfactory cues that remain along the trail well after
recreational usage.
If habitat is available, wildlife may move to areas farther from trails, beyond the areas of
influence, to avoid recreation-related disturbance (Reed et al. 2019). However, the greater the
proportion of a protected area occupied by trails, the fewer options there are for wildlife to move
outside of those areas of influence. There are simply fewer opportunities for wildlife to retreat
from nearby recreational users in an already shrinking habitat.
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The higher the level of recreation in protected areas, the greater the potential there is for the
effects of trails and their use to extend beyond habitat loss and individual-level effects
(behavioral and physiological) on wildlife. This may transition into population- and community-
level effects, including depletion of floral and faunal populations, alteration of the trophic
community structures, and reduction of biodiversity (CDFW 2015).
With increased recreational usage of trails through open spaces, comes increased exposure of
wildlife to humans. Habituated urban wildlife is less likely to avoid contact with humans, which
may increase the probability of human-wildlife conflicts and of attraction to anthropogenic food
sources; both are considered problematic in many urban areas (Whittaker and Knight 1998;
George and Crooks 2006). Wildlife habituation to humans may also increase wildlife aggression
toward humans, or render wildlife more vulnerable to predators, poaching, or roadkill (Whitaker
and Knight 1998; George and Crooks 2006; Marzano and Dandy 2012). Furthermore,
habituation of wildlife may impact their reproductive success. Habituation of adult individuals
may also be associated with negative consequences for their offspring as habituation of adults
does not necessarily lead to immediate habituation of juveniles (Reilly et al. 2017).
Recommended Potentially Feasible Mitigation Measure(s):
Mitigation Measure #1: CDFW recommends setting aside conserved acreage of sensitive
vegetation communities in a manner that is isolated and free from influence by recreational
usage. These conserved areas should be oriented to provide refugia for species that may be
flushed or relocated by the presence of trails.
For proposed preservation and/or restoration, the environmental document should include
measures to protect the targeted habitat values in perpetuity from direct and indirect negative
impacts. The objective should be to offset the Project-induced qualitative and quantitative losses
of wildlife habitat values. Issues that should be addressed include, but are not limited to,
restrictions on access, proposed land dedications, monitoring and management programs,
control of illegal dumping, water pollution, and increased human intrusion. An appropriate non-
wasting endowment should be provided for the long-term monitoring and management of
mitigation lands. CDFW recommends that mitigation occur at a state-approved bank or via an
entity that has been approved to hold and manage mitigation lands pursuant to Assembly Bill
1094 (2012), which amended Government Code sections 65965-65968. Under Government
Code section 65967(c), the lead agency must exercise due diligence in reviewing the
qualifications of a governmental entity, special district, or nonprofit organization to effectively
manage and steward land, water, or natural resources on mitigation lands it approves.
Mitigation Measure #2: Educational materials and signage should be made available to trail
users to keep aware of the impacts that human disturbance brings to open spaces. Hikers
should be made aware of the impacts that they have on surrounding habitat (such as noise or
smells), particularly during breeding seasons.
Mitigation Measure #3: CDFW recommends the City install appropriate public information
signage at trailheads to: 1) educate and inform the public about wildlife present in the area; 2)
advise on proper avoidance measures to reduce human-wildlife conflicts; 3) advise on proper
use of open space trails in a manner respectful to wildlife; and, 4) provide local contact
information to report injured or dead wildlife. Signage should be written in the language(s)
understandable to all those likely to recreate and use the trails. Signage should not be made of
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materials harmful to wildlife such as spikes or glass. The City should provide a long-term
maintenance plan to repair and replace the signs.
Mitigation Measure #4: Restrictions on types of activities allowed in some areas, such as
prohibiting dogs or restricting use to trails near active breeding habitat, will aid in minimizing
disturbance. Pets should be kept on leash and on trails at all times. Hikers should be
encouraged to clean up after their dogs and discourage animal waste as it tends to lead to
wildlife avoidance.
Mitigation Measure #5: Trash receptacles should be placed only at trailheads to avoid creating
an unnatural food source that may attract nuisance wildlife and to minimize waste in core habitat
areas.
Recommendation #1: Understanding wildlife responses to recreation and the area of influence
of human activities may help managers judge whether wildlife populations are experiencing
stress due to interactions with humans, and may aid in tailoring recreation plans to minimize
long-term effects to wildlife from disturbance. In an environmental document, CDFW
recommends including an analysis of recreational usage of the Summitridge trail system in
which current levels of traffic (hiker, biker, and dog) is compared to the expected increase in
traffic as a result of trail improvements.
Recommendation #2: People are often not aware of how their activities affect wildlife, even if
they see animals respond to their actions (Stalmaster and Kaiser 1998). By emphasizing how
human activities affect wildlife, people can associate their actions with either benefitting or
harming animal populations and begin to develop a conservation ethic (Miller et al. 2001). With
improved educational materials and outreach efforts, recreational users are more likely to
support restrictions if they understand how wildlife will benefit.
Comment #2: Impacts to Sensitive Vegetation Communities
Issue: Figure 5: Vegetation Communities and Other Land Uses from the MND is a map of the
vegetation communities found on the Project site. It shows that the Canyon Loop Trail runs
through the following Sensitive Natural Communities, including their respective rarity rankings
according to California Native Plant Society (CNPS):
Coast Live Oak Woodland and Forest (Quercus agrifolia) – S4
California sagebrush – black sagebrush scrub (Artemisia californica – Salvia
mellifera) – S3
Coast prickly pear scrub (Opuntia littoralis) – S3
Black sage scrub (Salvia mellifera) – S4
Scrub oak chapparal (Quercus berberidifolia) – S4
Specific impacts: The Project proposes work along the Canyon Loop Trail through Sensitive
Natural Communities but does not include the potential acreage of impacts resulting from
Project activities. The expansion of the southern portion of the Canyon Loop Trail by 1-2 feet in
width from currently condition is estimated to be about 0.4 miles long. With a lack of specificity
regarding acres impacted, potential loss of a sensitive vegetation community not previously
known or identified in the Project site may occur.
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Why impacts would occur: Project implementation includes grading, vegetation clearing, trail
construction, trail maintenance, and other activities. This may result in permanent loss and
potentially decline or local extirpation of a sensitive plant community.
Evidence impacts would be significant: CDFW considers plant communities, alliances, and
associations with a statewide ranking of S1, S2, S3 and S4 as sensitive and declining at the
local and regional level (Sawyer et al. 2008). An S3 ranking indicates there are 21 to 80
occurrences of this community in existence in California, S2 has 6 to 20 occurrences, and S1
has less than 6 occurrences. Impacts to sensitive vegetation communities should be considered
significant under CEQA unless they are clearly mitigated below a level of significance.
Inadequate avoidance, minimization, and mitigation measures for impacts to sensitive plant
species will result in the Project continuing to have a substantial adverse direct, indirect, and
cumulative effect, either directly or through habitat modifications, on any species identified as a
candidate, sensitive, or special status species in local or regional plans, policies, or regulations,
or by CDFW or U.S. Fish and Wildlife Service (USFWS).
Recommended Potentially Feasible Mitigation Measure(s):
Mitigation Measure #1: CDFW recommends mapping vegetation communities. Surveys should
be conducted by a qualified botanist with appropriate experience and knowledge of southern
California flora. Surveys should follow CDFW's Protocols for Surveying and Evaluating Impacts
to Special Status Native Plant Populations and Sensitive Natural Communities (CDFW 2018).
Surveys should be completed prior to implementing Project related ground disturbing activities.
Mitigation Measure #2: If the Project cannot feasibly avoid impacts to sensitive vegetation
communities, either during Project activities or over the life of the Project, the City should
mitigate for impacts at no less than 5:1 for impacts to S3 ranked communities and 7:1 for S2
communities.
Recommendation #1: In 2007, the State Legislature required CDFW to develop and maintain a
vegetation mapping standard for the state (Fish & G. Code, § 1940). This standard complies
with the National Vegetation Classification System, which utilizes alliance and association-
based classification of unique vegetation stands. CDFW utilizes vegetation descriptions found in
the Manual of California Vegetation (MCV) (CNPS 2020; Sawyer et al. 2008). To determine the
rarity ranking of vegetation communities on the Project site, the MCV alliance/association
community names should be provided as CDFW only tracks rare natural communities using this
classification system. This would allow CDFW to appropriately comment on potential impacts to
sensitive plants and vegetation communities.
Comment #3: Impacts to Nesting Birds
Issue: Page 4.4-5 of the MND summarizes the results of the focused bird surveys conducted for
the Project. The results indicate that this particular open space is actively used, high quality
habitat for multiple listed bird species. Within the study area are observations of coastal
California gnatcatcher (Polioptila californica californica, CAGN) and coastal cactus wren
(Campylorhynchus brunneicappilus sandiegensis), both California Species of Special Concern
(SSC). Page 4.4-5 states, “[b]ased on the results of the Focused Bird Survey Report, at least
five CAGN and five cactus wren territories were found to be present within the 500-foot survey
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City of Diamond Bar
November 13, 2020
Page 7 of 19
area. Four CAGN pairs and all five cactus wren pairs successfully fledged young in 2020 as
evidenced by firsthand observations during the surveys.”
Specific impact: Project construction and related activities may result in increased nesting
mortality due to nest abandonment or decreased feeding frequency. The Project may result in
temporal or permanent loss of bird nesting habitat.
Why impacts would occur: Construction activities, continued usage of trails, and routine
maintenance during the breeding season for nesting birds could result in the loss of fertile eggs
or nestlings or otherwise lead to nest abandonment. Impacts could result from noise
disturbances, increased human activity, dust, ground disturbing activities (e.g., staging, access,
excavation, and grading), and vibrations caused by heavy equipment. The Project as proposed
would clear vegetation that could provide bird nesting habitat (e.g., ground cover and shrubs).
The temporal or permanent loss of vegetation may substantially impact birds that could return to
the Project site year after year (Figueira et al. 2020; Haas 1998). Site fidelity exhibited across
the avian taxa reflects the benefits associated with previous knowledge of a particular location,
likely improving territory acquisition, foraging efficiency, potential breeding partners, and
predator avoidance (Figueira et al. 2020).
Evidence impacts would be significant: Nests of all birds and raptors are protected under
State laws and regulations, including Fish and Game Code, sections 3503 and 3503.5. Take or
possession of migratory nongame birds designated in the Federal Migratory Bird Treaty Act of
1918 (Code of Federal Regulations, Title 50, § 10.13) is prohibited under Fish and Game Code
section 3513. The loss of occupied habitat or reductions in the number of sensitive and special
status bird species, either directly or indirectly through nest abandonment or reproductive
suppression, would constitute a significant impact absent appropriate mitigation.
Recommended Potentially Feasible Mitigation Measure(s):
Mitigation Measure #1: CDFW recommends modifying Mitigation Measure BIO-3 in the MND
to fully avoid impacts to nesting birds by conditioning the environmental document to provide the
following language: “Project construction, equipment staging, mobilization, grading, ground
disturbance activities, and vegetation removal should be completed outside the avian breeding
season. The City should not perform any Project construction or activities or remove or
otherwise disturb vegetation on the project site, or adjacent to the site, from February 15 to
August 31, and as early as January 1, to avoid impacts to breeding/nesting birds and raptors.”
Mitigation Measure #2: If avoidance is not feasible, a qualified biologist should complete a
survey for nesting bird activity within a 500-foot radius of the Project footprint. Surveys should
begin no more than 14 days prior to the start of Project ground disturbing activities and should
be repeated for the duration of Project activities that occur during the bird nesting season.
Nesting bird surveys should be conducted at appropriate nesting times and concentrate on
potential roosting or perch sites. If Project activities are delayed or suspended for more than 7
days during the breeding season, surveys should be repeated before work can resume.
Mitigation Measure #3: If nesting birds or raptors are identified, a qualified biologist should
determine the nesting status and set up species-appropriate no-work buffers for construction
activities. CDFW recommends the following minimum no-disturbance buffers be implemented:
300 feet around active passerine (perching birds and songbirds) nests, 500 feet around active
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City of Diamond Bar
November 13, 2020
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non-listed raptor nests and 0.5 mile around active CESA-listed bird nests. No Project activities
should be allowed inside these buffers until the qualified biologist has determined that the birds
have fledged and are no longer reliant upon the nest or parental care for survival. These buffers
should be increased if needed to protect the nesting birds. Buffers should be clearly delineated
and marked around the active nest site as directed by the qualified biologist. Temporary fencing
and signage should be maintained for the duration of the Project as determined by the qualified
biologist. A qualified biologist should advise workers of the sensitivity of the buffered areas.
Workers should be advised not to work, trespass, or engage in activities that would disturb
nesting birds near or inside the buffer.
Comment #4: Impacts to Reptiles
Issue: According to page 4.4-3 of the MND, coastal whiptail (Aspidoscelis tigris stejnegeri) and
red-diamond rattlesnake (Crotalus ruber), both SSC, were found on the Project site during
habitat assessments and focused surveys. These observations are supported by a review of
California Natural Diversity Database (CNDDB), which shows a cluster of historic records of
these species throughout the southern half of the Project site.
Specific impact: Project ground disturbing activities such as grading and grubbing may result
in habitat destruction, causing the death or injury of adults, juveniles, eggs, or hatchlings. In
addition, the Project may remove habitat by eliminating vegetation that may support foraging
and breeding habitat.
Why impact would occur: Project implementation includes grading, vegetation clearing, and
other activities that may result in direct mortality, population declines, or local extirpation of
Special Status reptile species.
Evidence impact would be significant: CEQA provides protection not only for state and
federally listed species, but for any species including but not limited to SSC which can be shown
to meet the criteria for State listing. These SSC meet the CEQA definition of rare, threatened or
endangered species (CEQA Guidelines, § 15065). Take of SSC could require a mandatory
finding of significance by the Lead Agency, (CEQA Guidelines, § 15065).
Recommended Potentially Feasible Mitigation Measure(s):
Mitigation Measure #1: Due to potentially suitable habitat within the Project site, prior to
vegetation removal and/or grading, qualified biologists familiar with the reptile species behavior
and life history should conduct specialized surveys to determine the presence/absence of SSC.
Surveys should be conducted during active season when the reptiles are most likely to be
detected. Survey results, including negative findings, should be submitted to CDFW prior to
initiation of Project activities.
Mitigation Measure #2: To further avoid direct mortality, CDFW recommends that a qualified
biological monitor approved by CDFW be on-site during ground and habitat disturbing activities
to move out of harm’s way special status species that would be injured or killed by grubbing or
Project-related grading activities. It should be noted that the temporary relocation of on-site
wildlife does not constitute effective mitigation for the purposes of offsetting Project impacts
associated with habitat loss. If the Project requires species to be removed, disturbed, or
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City of Diamond Bar
November 13, 2020
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otherwise handled, we recommend that the Project clearly identify that the designated entity
should obtain all appropriate state and federal permits.
Comment #5: Impacts to Streams
Issue: Page 4.4-7 of the MND acknowledges the ephemeral nature of the on-site drainage,
likely carrying flows during rain events, and recognizes that the streambed is “jurisdictional
streambed under CDFW”. The trail system crosses this drainage a number of times and six
drainage crossings are proposed along the South Canyon Loop to improve drainage and reduce
erosion. Project related activities have the potential to impact riparian resources and are likely
subject to notification for a Lake and Streambed Alteration Agreement (LSA).
Specific impacts: The Project may result in the loss of streams and associated watershed
function and biological diversity. Grading and construction activities will likely alter the
topography, and thus the hydrology, of the Project site.
Why impacts would occur: Ground disturbing activities from grading and filling, water
diversions and dewatering would physically remove or otherwise alter existing streams or their
function and associated riparian habitat on the Project site. Downstream streams and
associated biological resources beyond the Project development footprint may also be impacted
by Project related releases of sediment and altered watershed effects resulting from Project
activities.
Evidence impacts would be significant: The Project may substantially adversely affect the
existing stream pattern of the Project site through the alteration or diversion of a stream, which
absent specific mitigation, could result in substantial erosion or siltation on site or off site of the
Project.
Recommended Potentially Feasible Mitigation Measure(s):
Mitigation Measure #1: The Project may result in the alteration of streams. For any such
activities, the Project applicant (or “entity”) must provide written notification to CDFW pursuant
to section 1600 et seq. of the Fish and Game Code. Based on this notification and other
information, CDFW determines whether a Lake and Streambed Alteration Agreement (LSA) with
the applicant is required prior to conducting the proposed activities. A notification package for a
LSA may be obtained by accessing CDFW’s web site at www.wildlife.ca.gov/habcon/1600.
CDFW’s issuance of an LSA for a project that is subject to CEQA will require CEQA compliance
actions by CDFW as a Responsible Agency. As a Responsible Agency, CDFW may consider
the CEQA document of the Lead Agency for the Project. However, the DEIR does not meet
CDFW’s standard at this time. To minimize additional requirements by CDFW pursuant to
section 1600 et seq. and/or under CEQA, the CEQA document should fully identify the potential
impacts to the stream or riparian resources and provide adequate avoidance, mitigation,
monitoring and reporting commitments for issuance of the LSA.
Mitigation Measure #2: Any LSA permit issued for the Project by CDFW may include additional
measures protective of streambeds on and downstream of the Project. The LSA may include
further erosion and pollution control measures. To compensate for any on-site and off-site
impacts to riparian resources, additional mitigation conditioned in any LSA may include the
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Mr. Ryan Wright
City of Diamond Bar
November 13, 2020
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following: avoidance of resources, on-site or off-site creation, enhancement or restoration,
and/or protection and management of mitigation lands in perpetuity.
Filing Fees
The Project, as proposed, would have an impact on fish and/or wildlife, and assessment of filing
fees is necessary. Fees are payable upon filing of the Notice of Determination by the Lead
Agency and serve to help defray the cost of environmental review by CDFW. Payment of the fee
is required in order for the underlying Project approval to be operative, vested, and final. (Cal.
Code Regs, tit. 14, § 753.5; Fish & Game Code, § 711.4; Pub. Resources Code, § 21089).
Conclusion
We appreciate the opportunity to comment on the Project to assist the City of Diamond Bar in
adequately analyzing and minimizing/mitigating impacts to biological resources. CDFW requests
an opportunity to review and comment on any response that the City has to our comments and
to receive notification of any forthcoming hearing date(s) for the Project [CEQA Guidelines; §
15073(e)]. If you have any questions or comments regarding this letter, please contact Andrew
Valand, Environmental Scientist, at Andrew.Valand@wildlife.ca.gov or (562) 342-2142.
Sincerely,
Erinn Wilson-Olgin
Environmental Program Manager I
Ec: CDFW
Victoria Tang, Los Alamitos – Victoria.Tang@wildlife.ca.gov
Andrew Valand, Los Alamitos – Andrew.Valand@wildlife.ca.gov
Felicia Silva, Los Alamitos – Felicia.Silva@wildlife.ca.gov
Ruby Kwan-Davis, Los Alamitos – Ruby.Kwan-Davis@wildlife.ca.gov
Frederic Rieman, Los Alamitos – Frederic.Rieman@wildlife.ca.gov
Susan Howell, San Diego – Susan.Howell@wildlife.ca.gov
CEQA Program Coordinator, Sacramento – CEQAcommentletters@wildlife.ca.gov
State Clearinghouse – State.Clearinghouse@opr.ca.gov
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Mr. Ryan Wright
City of Diamond Bar
November 13, 2020
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References:
California Department of Fish and Wildlife [CDFW]. 2015. California State Wildlife Action Plan,
2015 Update: A Conservation Legacy for Californians. Edited by Armand G. Gonzales and
Junko Hoshi, PhD. Prepared with assistance from Ascent Environmental, Inc.,
Sacramento, CA.
California Department of Fish and Wildlife [CDFW]. March 20,2018. Protocols for Surveying and
Evaluating Impacts to Special Status Native Plant Populations and Natural Communities
(see https://www.wildlife.ca.gov/Conservation/Plants).
Czech, B., P. R. Krausman, and P. K. Devers. 2000. Economic associations among causes of
species endangerment in the United States. BioScience 50:593–601.
Dyett & Bhatia. September 2019. Diamond Bar Environmental Impact Report 2040. Public
Review Draft. September 2019.
Figueira L. et al. 2020. Effects of breeding and molt activity on songbird site fidelity, The
Auk, https://doi.org/10.1093/auk/ukaa053.
George, S.L., and K. R. Crooks. 2006. Recreation and large mammal activity in an urban nature
reserve. Biological Conservation 133.1 (2006):107–117.
Haas, C. 1998. Effects of Prior Nesting Success on Site Fidelity and Breeding Dispersal: An
Experimental Approach, The Auk, Volume 115, Issue 4, 1 October 1998, Pages 929–936.
Hamilton, Robert. February 2019. Biological Resources Report for Open Space & Conservation
Element Diamond Bar General Plan Update.
Holmes, Aaron L.; Geupel, Geoffrey R. 2005. Effects of trail width on the densities of four
species of breeding birds in chaparral. In: Ralph, C. John; Rich, Terrell D., editors 2005.
Bird Conservation Implementation and Integration in the Americas: Proceedings of the
Third International Partners in Flight Conference. 2002 March 20-24; Asilomar, California,
Volume 1 Gen. Tech. Rep. PSW-GTR-191. Albany, CA: U.S. Dept. of Agriculture, Forest
Service, Pacific Southwest Research Station: p. 610-612.
Knight, R. L., and K. J. Gutzwiller, editors. 1995. Wildlife and recreationists: coexistence through
management and research. Island Press, Washington, D.C., USA.
Losos, E., J. Hayes, A. Phillips, D. Wilcove, and C. Alkire. 1995. Taxpayer-subsidized resource
extraction harms species. BioScience 45:446–455.
Lucas, E. 2020. A review of trail-related fragmentation, unauthorized trails, and other aspects of
recreation ecology in protected areas. California Fish and Wildlife, Recreation Special
Issue; 95-125.
Marzano, M., and N. Dandy. 2012. Recreationist behaviour in forests and the disturbance to
wildlife. Biodiversity and Conservation 21: 2967–2986.
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Mr. Ryan Wright
City of Diamond Bar
November 13, 2020
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Miller, S. G., R. L. Knight, and C. K. Miller. 1998. Influence of recreational trails on breeding bird
communities. Ecological Applications 8(1): 162-169.
National Research Council. 1995. Science and the Endangered Species Act. Washington, DC:
The National Academies Press. https://doi.org/10.17226/4978
Reed, S. E., C. L. Larson, and K. R. Crooks. 2019. Effects of human use of NCCP Reserves on
reptile and mammal species in San Diego. Wildlife Conservation Society Agreement No /
LAG #: P1582100.
Reilly, M. L., M. W. Tobler, D. L. Sonderegger, and P. Beier. 2017. Spatial and temporal
response of wildlife to recreational activities in the San Francisco Bay ecoregion. Biological
Conservation 207:117–126.
Sawyer, J.O., Keeler Wolf, T., and Evens J.M. 2008. A manual of California Vegetation, 2nd ed.
ISBN 978 0 943460 49 9.
Stalmaster, M. V., and J. L. Kaiser. 1998. Effects of recreational activity on wintering bald
eagles. Wildlife Monographs 137.
Taylor, A. R., and R. L. Knight. 2003. Wildlife responses to recreation and associated visitor
perceptions. Ecological Applications 13(4): 951-963.
Whittaker, D., and R. L. Knight. 1998. Understanding wildlife responses to humans. Wildlife
Society Bulletin 26:312–317.
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State of California – Natural Resources Agency GAVIN NEWSOM, Governor
DEPARTMENT OF FISH AND WILDLIFE CHARLTON H. BONHAM, Director
South Coast Region
3883 Ruffin Road
San Diego, CA 92123
(858) 467-4201
www.wildlife.ca.gov
CDFW recommends the following language to be incorporated into a future environmental document for the Project.
Biological Resources
Mitigation Measure Timing Responsible Party
MM-BIO-1 –
Sensitive
Vegetation
Avoidance
The City shall set aside conserved acreage of sensitive vegetation
communities in a manner that is isolated and free from influence by
recreational usage. These conserved areas shall be oriented to
provide refugia for species that may be flushed or relocated by the
presence of trails.
For proposed preservation and/or restoration, the final
environmental document shall include measures to protect the
targeted habitat values in perpetuity from direct and indirect
negative impacts. The objective shall be to offset the Project-
induced qualitative and quantitative losses of wildlife habitat
values. Issues that shall be addressed include, but are not limited
to, restrictions on access, proposed land dedications, monitoring
and management programs, control of illegal dumping, water
pollution, and increased human intrusion. An appropriate non-
wasting endowment shall be provided for the long-term monitoring
and management of mitigation lands. Off-site mitigation shall occur
at a state-approved bank or via an entity that has been approved
to hold and manage mitigation lands pursuant to Assembly Bill
1094 (2012), which amended Government Code sections 65965-
65968. Under Government Code section 65967(c), the lead
agency must exercise due diligence in reviewing the qualifications
of a governmental entity, special district, or nonprofit organization
to effectively manage and steward land, water, or natural
resources on mitigation lands it approves.
Prior to
construction
City of Diamond
Bar
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City of Diamond Bar
November 13, 2020
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MM-BIO-2 –
Educational
Materials
Educational materials and signage shall be made available to trail
users to keep aware of the impacts that human disturbance brings
to open spaces. Hikers shall be made aware of their impacts to
surrounding habitat (such as noise or smells), particularly during
breeding seasons.
Prior to
construction
City of Diamond
Bar
MM-BIO-3 –
Informational
Signage
The City shall install appropriate public information signage at
trailheads to: 1) educate and inform the public about wildlife
present in the area; 2) advise on proper avoidance measures to
reduce human-wildlife conflicts; 3) advise on proper use of open
space trails in a manner respectful to wildlife; and, 4) provide local
contact information to report injured or dead wildlife. Signage shall
be written in the language(s) understandable to all those likely to
recreate and use the trails. Signage shall not be made of materials
harmful to wildlife such as spikes or glass. The City shall provide a
long-term maintenance plan to repair and replace the signs.
Prior to
construction
City of Diamond
Bar
MM-BIO-4 – Pet
Policy
Pets shall be kept on leash and on trails at all times. Hikers shall
be encouraged to clean up after their dogs and discourage animal
waste as it tends to lead to wildlife avoidance.
Prior to
construction
City of Diamond
Bar
MM-BIO-5 –
Placement of
Trash
Receptacles
Trash receptacles shall be placed only at trailheads to avoid
creating an unnatural food source that may attract nuisance wildlife
and to minimize waste in core habitat areas.
Prior to
construction
City of Diamond
Bar
MM-BIO-6 –
Sensitive
Vegetation
Surveys
Vegetation surveys shall be conducted by a qualified botanist with
appropriate experience and knowledge of southern California flora.
Surveys shall follow CDFW's Protocols for Surveying and
Evaluating Impacts to Special Status Native Plant Populations and
Sensitive Natural Communities (CDFW 2018). Surveys shall be
completed prior to implementing Project related ground disturbing
activities.
Prior to
construction
City of Diamond
Bar
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City of Diamond Bar
November 13, 2020
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MM-BIO-7 –
Sensitive
Vegetation
Replacement
If the Project cannot feasibly avoid impacts to sensitive vegetation
communities, either during Project activities or over the life of the
Project, the City shall mitigate for impacts at no less than 5:1 for
impacts to S3 ranked communities and 7:1 for S2 communities.
Prior to
construction
City of Diamond
Bar
MM-BIO-8 –
Nesting Bird
Season
The City shall modify Mitigation Measure BIO-3 in the MND to fully
avoid impacts to nesting birds by conditioning the environmental
document to provide the following language: “Project construction,
equipment staging, mobilization, grading, ground disturbance
activities, and vegetation removal shall be completed outside the
avian breeding season. The City shall not perform any Project
construction or activities or remove or otherwise disturb vegetation
on the project site, or adjacent to the site, from February 15 to
August 31, and as early as January 1, to avoid impacts to
breeding/nesting birds and raptors.”
Prior to
construction
City of Diamond
Bar
MM-BIO-9 –
Nesting Bird
Surveys
If avoidance is not feasible, a qualified biologist shall complete a
survey for nesting bird activity within a 500-foot radius of the
Project footprint. Surveys shall begin no more than 14 days prior to
the start of Project ground disturbing activities and shall be
repeated for the duration of Project activities that occur during the
bird nesting season. Nesting bird surveys shall be conducted at
appropriate nesting times and concentrate on potential roosting or
perch sites. If Project activities are delayed or suspended for more
than 7 days during the breeding season, surveys shall be repeated
before work can resume.
Prior to
construction
City of Diamond
Bar
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City of Diamond Bar
November 13, 2020
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MM-BIO-10 –
Nesting Bird
Avoidance
Buffers
If nesting birds or raptors are identified, a qualified biologist shall
determine the nesting status and set up species-appropriate no-
work buffers. The following minimum no-disturbance buffers shall
be implemented: 300 feet around active passerine (perching birds
and songbirds) nests, 500 feet around active non-listed raptor
nests and 0.5 mile around active CESA-listed bird nests. No
Project activities shall be allowed inside these buffers until the
qualified biologist has determined that the birds have fledged and
are no longer reliant upon the nest or parental care for survival.
These buffers shall be increased if needed to protect the nesting
birds. Buffers shall be clearly delineated and marked around the
active nest site as directed by the qualified biologist. Temporary
fencing and signage shall be maintained for the duration of the
Project as determined by the qualified biologist. A qualified
biologist shall advise workers of the sensitivity of the buffered
areas. Workers shall be advised not to work, trespass, or engage
in activities that would disturb nesting birds near or inside the
buffer.
Prior to
construction
City of Diamond
Bar
MM-BIO-11 –
Reptile Surveys
Prior to vegetation removal and/or grading, qualified biologists
familiar with the reptile species behavior and life history shall
conduct specialized surveys to determine the presence/absence of
Species of Special Concern (SSC). Surveys shall be conducted
during active season when the reptiles are most likely to be
detected. Survey results, including negative findings, shall be
submitted to CDFW prior to initiation of Project activities.
Prior to
construction
City of Diamond
Bar
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City of Diamond Bar
November 13, 2020
Page 17 of 19
MM-BIO-12 –
Moving Out of
Harm’s Way
A qualified biological monitor, approved by CDFW, shall be on-site
during ground and habitat disturbing activities to move out of
harm’s way special status species that would be injured or killed by
grubbing or Project-related grading activities. It shall be noted that
the temporary relocation of on-site wildlife does not constitute
effective mitigation for the purposes of offsetting Project impacts
associated with habitat loss. If the Project requires species to be
removed, disturbed, or otherwise handled, the Project shall clearly
identify that the designated entity shall obtain all appropriate state
and federal permits.
Prior to
construction
City of Diamond
Bar
MM-BIO-13 –
Notification for
Lake and
Streambed
Alteration
Agreement
Project applicant (or “entity”) must provide written notification to
CDFW pursuant to section 1600 et seq. of the Fish and Game
Code. Based on this notification and other information, CDFW
determines whether a Lake and Streambed Alteration Agreement
(LSA) with the applicant is required prior to conducting the
proposed activities. A notification package for a LSA may be
obtained by accessing CDFW’s web site at
www.wildlife.ca.gov/habcon/1600.
CDFW’s issuance of an LSA for a project that is subject to CEQA
will require CEQA compliance actions by CDFW as a Responsible
Agency. As a Responsible Agency, CDFW may consider the
CEQA document of the Lead Agency for the Project. However, the
DEIR does not meet CDFW’s standard at this time. To minimize
additional requirements by CDFW pursuant to section 1600 et seq.
and/or under CEQA, the CEQA document shall fully identify the
potential impacts to the stream or riparian resources and provide
adequate avoidance, mitigation, monitoring and reporting
commitments for issuance of the LSA.
Prior to
construction
City of Diamond
Bar
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City of Diamond Bar
November 13, 2020
Page 18 of 19
MM-BIO-14 –
Lake and
Streambed
Alteration
Agreement
Components
Any LSA permit issued for the Project by CDFW may include
additional measures protective of streambeds on and downstream
of the Project. The LSA may include further erosion and pollution
control measures. To compensate for any on-site and off-site
impacts to riparian resources, additional mitigation conditioned in
any LSA may include the following: avoidance of resources, on-
site or off-site creation, enhancement or restoration, and/or
protection and management of mitigation lands in perpetuity.
Prior to
construction
City of Diamond
Bar
Recommendations
REC-BIO-1 –
Analysis of
Recreational
Usage
Understanding wildlife responses to recreation and the area of
influence of human activities may help managers judge whether
wildlife populations are experiencing stress due to interactions with
humans, and may aid in tailoring recreation plans to minimize long-
term effects to wildlife from disturbance. In a subsequent
environmental document, CDFW recommends including an
analysis of recreational usage of the Summitridge trail system in
which current levels of traffic (hiker, biker, and dog) is compared to
the expected increase in traffic as a result of trail improvements.
REC-BIO-2 –
Education &
Outreach
People are often not aware of how their activities affect wildlife,
even if they see animals respond to their actions (Stalmaster and
Kaiser 1998). By emphasizing how human activities affect wildlife,
people can associate their actions with either benefitting or
harming animal populations and begin to develop a conservation
ethic (Miller et al. 2001). With improved educational materials and
outreach efforts, recreational users are more likely to support
restrictions if they understand how wildlif e will benefit.
REC-BIO-3 –
National
Vegetation
Classification
System
In 2007, the State Legislature required CDFW to develop and
maintain a vegetation mapping standard for the state (Fish & G.
Code, § 1940). This standard complies with the National
Vegetation Classification System, which utilizes alliance and
association-based classification of unique vegetation stands.
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City of Diamond Bar
November 13, 2020
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CDFW utilizes vegetation descriptions found in the Manual of
California Vegetation (MCV) (CNPS 2020; Sawyer et al. 2008). To
determine the rarity ranking of vegetation communities on the
Project site, the MCV alliance/association community names shall
be provided as CDFW only tracks rare natural communities using
this classification system. This would allow CDFW to appropriately
comment on potential impacts to sensitive plants and vegetation
communities.
DocuSign Envelope ID: D09091D4-BECA-4DE0-AD04-67F483BE3E39
Appendix B CAGN Avoidance and
Minimization Strategy for the Canyon Loop
Trail Improvement Project
5 Hutton Centre Drive, Suite 500 | Santa Ana, CA 92707
Office: 949.472.3505 | Fax: 949.472.8373 | mbakerintl.com MBAKERINTL.COM
JN 178669 July 22, 2022
U.S. DEPARTMENT OF THE INTERIOR, FISH AND WILDLIFE SERVICE
Attn: Carol Roberts, Division Supervisor
Carlsbad Fish and Wildlife Office
2177 Salk Avenue, Suite 250
Carlsbad, California 92008
SUBJECT: Coastal California Gnatcatcher Avoidance and Minimization Strategy for the
Canyon Loop Trail Improvement Project – City of Diamond Bar, Los Angeles
County, California
Dear Ms. Roberts:
Michael Baker International (Michael Baker) is writing to the U.S. Fish and Wildlife Service (USFWS) to
seek concurrence that the proposed avoidance and minimization strategy as described in this memo is
adequate to offset potential impacts related to the Canyon Loop Trail Improvement Project (project) on the
federally threatened coastal California gnatcatcher (CAGN; Polioptila californica californica). This memo
will discuss the project and its goals, results of focused CAGN surveys conducted on-site in 2020,
anticipated project impacts, and summarize proposed mitigation and avoidance and minimization measures.
Project Location
The project is generally located south of State Route 60, east of State Route 57, north of Grand Avenue,
and west of Chino Hills Parkway in the City of Diamond Bar, Los Angeles County, California. The project
is depicted in Sections 11, 14, and 15 of Township 2 South, Range 9 West, on the U.S. Geological Survey’s
(USGS) San Dimas, California 7.5-minute quadrangle (refer to Figure 1, Regional and Site Vicinity, in
Attachment A). Specifically, the project is located along the existing Canyon Loop Trail within
Summitridge Park (refer to Figure 2, Project Site, in Attachment A).
Project Description
The City of Diamond Bar proposes to implement a series of improvements to the existing Canyon Loop
Trail. The intent of the project is primarily to realign the trail, improve drainage to minimize erosion of the
trail, enhance the use of the trail where the gradients are steep, re-grade cross slopes, and consider amenities
such as directional and interpretive signage, rest areas with benches, small shade shelters, climbing steps
with cobblestone swale channelization, and water diverting improvements where necessary (refer to Figure
3, Initial Conceptual Design, in Attachment A). Such trail improvements will reward hikers and visitors
with 360-degree views of open space. Although the trail will be widened as necessary to ensure a consistent
five-foot width, the existing trail is not a high-usage amenity, and post-project conditions are not expected
to increase the average numbers of daily trail users.
Canyon Loop Trail Improvement Project 2
Coastal California Gnatcatcher Memo
2020 Coastal California Gnatcatcher Protocol Surveys
Protocol surveys for CAGN were conducted along, and in areas of suitable habitat within 500 feet of, the
existing Canyon Loop Trail in 2020. A total of six (6) surveys were conducted by Michael Baker biologists
Ryan Winkleman (USFWS recovery permit TE-88331A-2, California Department of Fish and Wildlife
scientific collecting permit SC-182750017), Ashley Spencer, and Tom Millington between May 26 and
July 1, 2020. The surveys followed the CAGN guidelines described in the USFWS protocol Coastal
California Gnatcatcher (Polioptila californica californica) Presence/Absence Survey Guidelines, February
28, 1997 (USFWS 1997).
At least five (5) CAGN territories were mapped during the 2020 focused surveys (refer to Attachment B). The
surveyors found four (4) nests in two (2) of these territories during the surveys, one (1) of which successfully led
to chicks fledging during the six-week survey period. Of the minimum five territories, four (4) of the territories
had fledgling chicks at some point during the survey effort. The boundaries of Territories 3 and 5 expanded over
time due to post-breeding dispersal, with Territory 5 potentially undergoing two separate instances of dispersal to
two areas where no CAGN had been previously detected. Many of the territories were directly adjacent to, crossed
over, or were at least in close proximity to proposed trail improvement areas. Of the nests that were found, the
closest nest (CAGN Territory 2 Nest #1) was approximately 70 feet from the Canyon Loop Trail. Biologists found
three separate nests in this territory during the survey effort, all of which failed.
Focused surveys for CAGN on behalf of this project were not conducted in either 2021 or 2022. However,
according to records in the eBird database, this species has been documented at this location as recently as June
2022 (eBird 2022).
Project Impacts
The project will result in the permanent removal of vegetated habitat directly adjacent to the existing trail (refer
to Figure 4, Final Project Impacts, in Attachment A). However, in most areas, the trail is already generally wide
enough for the project’s goals, resulting in minimal need for additional widening and very minimal disturbance
to surrounding vegetation. Acreages of habitats that are suitable for CAGN and that will be permanently lost as a
result of this project are displayed in Table 1.
Table 1: Impacts to California Gnatcatcher Habitat
Vegetation Communities Permanent Impacts (acres)*
California Sagebrush – Black Sage Scrub 0.009
Disturbed California Sagebrush – Black Sage Scrub 0.128
Coast Prickly Pear Scrub1 0.050
TOTAL* 0.187
1 State Rarity Rank S3 Sensitive Natural Community (California Department of Fish and Wildlife [CDFW] 2021).
*Total may not equal to sum due to rounding.
The project may also result in general disturbance to birds, if present. Because of the existing use of the trail, it is
unlikely that any birds would nest within the impact/removal area. In addition, because of the very small and
generally very narrow amount of vegetation that is to be removed, which will in turn be spread out over
Canyon Loop Trail Improvement Project 3
Coastal California Gnatcatcher Memo
approximately 0.4 mile and with the presence of suitable vegetation that is located along the entire trail and in the
vicinity, direct injury or mortality are considered to be extremely unlikely. Individual birds are most likely to be
directly affected through avoidance of particular areas where the construction crew may be actively working, but
because the on-site population was documented to be using relatively large territories compared to the impact
areas, it is unlikely that any bird(s) would be flushed into a neighboring territory or otherwise unfamiliar area
where adverse impacts or interactions could occur. The general effect on individual birds is expected to be very
minimal.
Proposed Avoidance and Minimization
The City of Diamond Bar has committed to the following avoidance and minimization strategy to reduce
the potential for direct impacts on CAGN.
Avoidance of CAGN Nesting Period
To reduce potential impacts to CAGN in areas surrounding the project site, the project’s construction schedule
has been adjusted to completely avoid the CAGN nesting period. According to the project’s schedule, construction
would begin in September 2022 and end in January 2023, falling outside of the CAGN nesting period and
avoiding any impacts to breeding birds or their young.
Mitigation Monitoring and Reporting Program
As part of the project’s approved Mitigation Monitoring and Reporting Program (MMRP) associated with its
Mitigated Negative Declaration (MND), several avoidance and minimization measures (AMMs) were included
to reduce impacts to biological resources. The following AMM applies specifically to CAGN and would only
apply if the project’s construction schedule cannot be met:
BIO-3: If project-related construction activities are initiated during the nesting season for CAGN
and cactus wren (CACW; Campylorhynchus brunneicapillus) (February 15th through
September 15th), a nesting bird clearance survey shall be conducted within seven days
prior to the start of construction within a 500-foot buffer of the project site. The survey
shall be conducted by a qualified biologist with demonstrable experience identifying
CAGN and CACW nesting behavior and finding their nests, and who has been approved
by the USFWS to conduct a CAGN survey. If an active CAGN or CACW nest is found
during the survey, no project-related construction shall be allowed within 500 feet of an
active CAGN nest or 300 feet of an active CACW nest, or within an alternative safe
distance as determined by the qualified biologist based on topography, visual shielding,
nest progress, and the type of construction and associated disturbance, until the active nest
has been determined by the qualified biologist to have failed or to have successfully gone
to completion (i.e., the nestlings have fledged and are no longer reliant on the nest). Results
of the nesting bird clearance survey shall be compiled in a memorandum and submitted to
the City and the USFWS for project records.
Canyon Loop Trail Improvement Project 4
Coastal California Gnatcatcher Memo
Additional Avoidance and Minimization Measures
The City of Diamond Bar has committed to the following additional AMMs, separate from the MND and MMRP,
to further protect CAGN:
AMM-1: Prior to initiating project activities, a qualified biologist shall prepare and present a
Workers Environmental Awareness Program (WEAP) training for all contractors,
subcontractors, and workers expected to be on-site throughout the entire construction
period. The WEAP shall include a brief review of any special-status species, including
habitat requirements and where they might be found, and other sensitive biological
resources that could occur in and adjacent to the project (e.g., vegetation). The WEAP shall
also include a brief discussion of regulatory protections and consequences for violating
environmental laws.
AMM-2: Prior to initiating project activities, the construction contractor shall utilize fencing,
flagging, signage, or another relatively unintrusive method of delineating the boundaries
of the areas to be cleared so as to minimize, to the extent possible, the amount of overreach
during vegetation removal and confine removals to only approved areas. A qualified
biologist shall inspect and approve the boundaries no earlier than 48 hours prior to the start
of construction and no later than the morning of the start of construction.
Project Construction Methods
To further minimize construction disturbance, the City of Diamond Bar has committed to pursuing contractor
bids that utilize pedestrian/foot crews, with up to one (1) piece of heavy equipment, a Bobcat skid-steer loader.
The project’s Request for Proposal (RFP) has not yet been released but will stipulate that only those bids that
incorporate these terms will be considered.
Habitat Mitigation
The California Department of Fish and Wildlife (CDFW) reviewed the project’s MND and provided a comment
letter to the City of Diamond Bar on November 13, 2020. Comment #2 required that the City of Diamond Bar
mitigate the permanent loss of sensitive vegetation communities as described in the California Natural
Community List (CDFW 2021). Of the on-site vegetation communities that could support CAGN, coast prickly
pear scrub is considered a sensitive (S3) community by the CDFW requiring mitigation. To comply with this
request, Michael Baker contacted the nearby Soquel Canyon Mitigation Bank (SCMB) on behalf of the City of
Diamond Bar to determine if mitigation credits for the loss of 0.050 acre of coast prickly pear scrub were available.
The SCMB does not have any remaining credits to mitigate for the loss of this community. As a result, the City
of Diamond Bar has agreed to mitigate for the loss of coast prickly pear scrub through on-site restoration and
enhancement at an anticipated 5:1 ratio (subject to pending negotiations with CDFW). Separate from this, the
City of Diamond Bar has designed the project to block/fence extraneous trail sections to minimize uncontrolled
access by recreationists and to encourage trail users to only use the approved and intended trail. As part of the
proposed on-site mitigation, the blocked trail section would be restored with coast prickly pear scrub not only as
part of the acreage fulfillment, but also to serve as deterrence against future trespassing.
Canyon Loop Trail Improvement Project 5
Coastal California Gnatcatcher Memo
Conclusion
The proposed project will result in a very minor habitat modification of 0.187 acre of occupied CAGN habitat
along the existing Canyon Loop Trail in Summitridge Park in the City of Diamond Bar. The project consists of
various trail improvements, but in general will result in the existing trail being widened a total of 1-2 feet where
the trail is not already wide enough. The City of Diamond Bar proposes an avoidance and minimization strategy
to reduce impacts to CAGN, as summarized below:
The project will be scheduled for construction between September 2022 and January 2023, outside of the
CAGN nesting season and during a time when hatch year birds should be independent and no longer as
vulnerable as when they first fledge from the nest.
Should construction be delayed and occur after February 15th, 2023, nesting bird clearance surveys
focusing on CAGN and incorporating spatial avoidance of any active nests will be required.
A WEAP describing sensitive biological resources will be presented to all construction personnel.
The project will be required to delineate all trail-widening boundaries to avoid or minimize any overreach
during vegetation removal.
The City of Diamond Bar has committed to using a maximum of one Bobcat skid-steer loader and
otherwise all foot crews for construction work.
A portion of the habitat that will be lost, 0.050 acre classified as coast prickly pear scrub will be mitigated
on-site at an anticipated ratio of 5:1 (subject to pending negotiations with CDFW).
Existing extraneous trail areas will be fenced, closed to public access, and planted with coast prickly pear
scrub to fulfill mitigation requirements and deter future trespassers.
Michael Baker seeks concurrence from the USFWS that the proposed avoidance and minimization strategy as
outlined above will reduce the level of impacts to CAGN and its habitat to below a level of significance to the
point where the project is not expected to require an Incidental Take Permit (ITP) or any form of Habitat
Conservation Plan. Michael Baker’s determination that an ITP under Section 10(a)(1)(B) of the Endangered
Species Act is not necessary is based on review and evaluation of the criteria included in the 2018 USFWS
Memorandum FWS/AES/067974, Guidance on trigger for an incidental take permit under section 10 (a)(1)(B)
of the Endangered Species Act where occupied habitat or potentially occupied habitat is being modified.1
Please do not hesitate to contact me at (949) 533-0918 or ryan.winkleman@mbakerintl.com should you have any
questions or require further information.
Sincerely,
Ryan Winkleman
Senior Biologist
Natural Resources and Regulatory Permitting
1 https://www.fws.gov/sites/default/files/documents/guidance-on-when-to-seek-an-incidental-take-permit.pdf
Canyon Loop Trail Improvement Project 6
Coastal California Gnatcatcher Memo
Attachments:
A. Project Figures
B. 2020 Focused Survey Report
C. References
Attachment A
Project Figures
Regional and Site Vicinity
Figure 1
°0 10.5
Miles6/17/2022 JN \\IRVICA1FS1.bkr.mbakercorp.com\HROOT\pdata\178669\GIS\MXD\CAGN Memo\Fig 01 Regional and Site Vicinity.mxd RPLegend
Project Site
CANYON LOOP TRAIL IMPROVEMENT PROJECT
COASTAL CALIFORNIA GNATCATCHER MEMO
Source: USGS 7.5-Minute topographic quadrangle maps: Ontario, Prado Dam, San Dimas, and Yorba Linda, California (2018)
^
Project Location
Dare CtPeakCtWynnewoodDr
SummitridgeDrProject Site6/22/2022 JN H:\pdata\178669\GIS\MXD\CAGN Memo\Fig 02 Project Site.mxd RPSource: Nearmap, 2020 Figure 2
0 220110
Feet
CANYON LOOP TRAIL IMPROVEMENT PROJECT
COASTAL CALIFORNIA GNATCATCHER MEMO
°
Legend
Canyon Loop Trail
Impact Area (0.41 acre)
!>Reference Point
Dare CtInitial Conceptual Design6/17/2022 JN \\IRVICA1FS1.bkr.mbakercorp.com\HROOT\pdata\178669\GIS\MXD\CAGN Memo\Fig 03 Initial Conceptual Design.mxd RPSource: Richard Fisher Associates, 2019 Figure 3
CANYON LOOP TRAIL IMPROVEMENT PROJECT
COASTAL CALIFORNIA GNATCATCHER MEMO
!(
!(
!(
!(
!>
!>
Nest #1
Nest #2
Nest #3
Nest #1
34.004845-117.796461
34.001339-117.802862
Final Project Impacts6/22/2022 JN H:\pdata\178669\GIS\MXD\CAGN Memo\Fig 04 Final Project Impacts.mxd RPSource: Nearmap, 2020 Figure 4
0 15075
Feet
CANYON LOOP TRAIL IMPROVEMENT PROJECT
COASTAL CALIFORNIA GNATCATCHER MEMO
°
Legend
Final Project Design
50-foot Buffer
Vegetation Communities
(Acres in Impact Area)
California Sagebrush -
Black Sage Scrub
(0.01 acre)
Coast Live Oak
Woodland and Forest
(0.01 acre)
Coast Prickly Pear
Scrub (0.05 acre)
Disturbed California
Sagebrush - Black
Sage Scrub
(0.13 acre)
Scrub Oak Chaparral
(0.01 acre)
2020 Survey Results
CAGN Territories
Territory #2
Territory #3
Territory #3
(Post-breeding
Dispersal)
Territory #4
Territory #5
CAGN Nests
!(Successful Nest
!(Failed Nest
!>Reference Point
Attachment B
2020 Focused Survey Report
August 7, 2020 178669
City of Diamond Bar
Contact: Mr. Ryan Wright
21810 Copley Drive
Diamond Bar, CA 91765
SUBJECT: Results of Coastal California Gnatcatcher and Cactus Wren Focused Surveys for the
Canyon Loop Trail Improvement Project in the City of Diamond Bar, Los Angeles
County, California
Dear Mr. Wright:
Michael Baker International (Michael Baker) is pleased to submit this report to the City of Diamond Bar
(City) documenting the results of coastal California gnatcatcher (Polioptila californica californica; CAGN)
and cactus wren (Campylorhynchus brunneicapillus; CACW) focused surveys conducted for the Canyon
Loop Trail Improvement Project (project or project site) located in the City of Diamond Bar, Los Angeles
County, California. Surveys occurred during the 2020 field season, when Michael Baker was contracted by
the City to perform CAGN and CACW surveys in suitable habitat within 500 feet of the proposed project.
Project Location
The survey area include the project site plus suitable CAGN and CACW habitat within a 500-foot buffer,
and is generally located south of State Route 60, east of State Route 57, north of Grand Avenue, and west
of Chino Hills Parkway in the City of Diamond Bar, Los Angeles County, California (refer to Figure 1,
Regional Vicinity, in Attachment A). The survey area is depicted in Sections 11 and 14 of Township 2
south, Range 9 west, on the United States Geological Survey’s (USGS) San Dimas, California 7.5-minute
quadrangle (USGS 1981). Specifically, the survey area is located along the Canyon Loop Trail within
Summitridge Park (refer to Figure 2, Survey Area, in Attachment A).
Project Description
The City of Diamond Bar proposes to implement a series of improvements to the existing Canyon Loop
Trail. The intent of the project is primarily to realign the trail, improve drainage to minimize erosion of the
trail, enhance the use of the trail where the gradients are steep, re-grade cross slopes, and consider amenities
such as directional and interpretive signage, rest areas with benches, small shade shelters, climbing steps
with cobblestone swale channelization, and water diverting improvements where necessary. Such trail
improvements will reward hikers and visitors with 360-degree views of open space.
Regulatory Framework
Federal Endangered Species Act of 1973
As defined within the Federal Endangered Species Act of 1973 (FESA), an endangered species is any
Canyon Loop Trail Improvement Project 2
Coastal California Gnatcatcher and Cactus Wren Focused Survey Results
animal or plant listed by regulation as being in danger of extinction throughout all or a significant portion
of its geographical range. A threatened species is any animal or plant that is likely to become endangered
within the foreseeable future throughout all or a significant portion of its geographical range. Without a
special permit, Federal law prohibits the “take” of any individuals or habitat of Federally-listed species.
Under Section 9 of the FESA, take is defined as “harass, harm, pursue, hunt, shoot, wound, kill, trap,
capture, or collect or attempt to engage in any such conduct.” The term “harm” has been clarified to include
“any act which actually kills or injures fish or wildlife, and emphasizes that such acts may include
significant habitat modification or degradation that significantly impairs essential behavioral patterns of
fish or wildlife.” Enforcement of FESA is administered by the U.S. Fish and Wildlife Service (USFWS).
Under the definition used by the FESA, “Critical Habitat” refers to specific areas within the geographical
range of a species that were occupied at the time it was listed that contain the physical or biological features
that are essential to the survival and eventual recovery of that species and that may require special
management considerations or protection, regardless of whether the species is still extant in the area. Areas
that were not known to be occupied at the time a species was listed can also be designated as Critical Habitat
if they contain one or more of the physical or biological features that are essential to that species’
conservation and if the occupied areas are inadequate to ensure the species’ recovery. If a project may result
in take or adverse modification to a species’ designated Critical Habitat and the project has a Federal nexus,
the project proponent may be required to provide suitable mitigation. Projects with a Federal nexus may
include projects that occur on Federal lands, require Federal permits (e.g., Clean Water Act Section 404
permit), or receive any Federal oversight or funding. If there is a Federal nexus, then the Federal agency
that is responsible for providing funds or permits would be required to consult with the USFWS under the
FESA.
Species Background
Coastal California Gnatcatcher
CAGN is a Federally threatened species with restricted habitat requirements, being an obligate resident of
sage scrub habitats, particularly—but not exclusively—those that are dominated by California sagebrush
(Artemisia californica). This species generally occurs below 750 feet elevation in coastal regions and below
1,500 feet inland. It ranges from Ventura County south to San Diego County and northern Baja Califo rnia
and is less common in sage scrub with a high percentage of tall shrubs. CAGN is considered a short-distance
disperser through contiguous, undisturbed habitat (USFWS 2010). However, juveniles are capable of
dispersing long distances (up to 14 miles) across fragmented and highly disturbed sage scrub habitat
(USFWS 2010). CAGN prefers habitat with more low-growing vegetation (< 3 feet high). CAGN breeds
between mid-February and the end of August, with peak activity from mid-March to mid-May. Population
declines are attributed to loss of sage scrub habitat due to development, as well as brown-headed cowbird
(Molothrus ater) nest parasitism. Federally designated Critical Habitat for CAGN is not located within or
directly adjacent to the survey area. The primary constituent elements essential to support the biological
needs of foraging, reproducing, rearing of young, intra-specific communication, dispersal, genetic
exchange, or sheltering for CAGN are:
1) Dynamic and successional sage scrub habitats and associated vegetation (Riversidean alluvial fan
sage scrub, coastal sage-chaparral scrub, etc.) that provide space for individual and population
growth, normal behavior, breeding, reproduction, nesting, dispersal and foraging; and
Canyon Loop Trail Improvement Project 3
Coastal California Gnatcatcher and Cactus Wren Focused Survey Results
2) Non-sage scrub habitats such as chaparral, grassland, and riparian areas in proximity to sage scrub
habitats that provide linkages to help with dispersal, foraging, and nesting (USFWS 2007).
The survey area provides abundant suitable habitat for CAGN, although there are large sections of the
survey area that are highly disturbed by non-native plants.
Cactus Wren
CACWs are a somewhat common avian species found within arid and semi-arid regions of southern
California. The subspecies coastal cactus wren (C. b. sandiegensis; CCAWC) is found within a very limited
range of southern California and is designated by CDFW as a Species of Special Concern (SSC). CCACW
has more heavily spotted underparts more closely blending into the dark breast spot, less of a cinnamon-
buff wash to the underparts, and extensive white in the interior tail feathers, as opposed to the continental
desert subspecies and subspecies along the Los Angeles County coast, C.b. anthonyi, which has finer belly
spotting more demarcated from the prominent breast spot, a heavier cinnamon-wash buff to the underparts,
and white generally restricted to the outermost tail feather (rectrix 6) and occasionally onto rectrix 5 (the
next feather in from the outside) (Rea and Weaver 1990). CCACW have a range which extends from
extreme northwestern Baja California north at least through the coastal lowlands of San Diego County
(Shuford and Gardali 2008). The actual northern limit of its range is uncertain because of the lack of
specimens from northwestern San Diego County and most of Orange County. However, observations made
in the field based on differences in song (slower frequency and lower pitch) and visual assessments suggest
approximately the vicinity of State Route 74 (Ortega Highway) in Orange County may be the northern limit
of CCACW, and this is apparently the range limit accepted by CDFW (Shuford and Gardali 2008).
CACWS breed from early March through July and are mainly restricted to thickets of chollas
(Cylindropuntia prolifera) or prickly-pear cacti (i.e., Opuntia littoralis, O. oricola) large enough to protect
from predation. Suitable habitat conditions are normally found on south-facing slopes, at bases of hillsides,
or in dry washes. Territories have been recorded as occurring at elevations below 1,500 feet above mean
sea level (amsl) and averaging three (3) acres in size (Shuford and Gardali 2008). CACWs forage on the
ground primarily for insects such as beetles, ants, wasps, grasshoppers, butterflies, and spiders.
The survey area provides several distinct patches of the undisturbed coast prickly pear scrub habitat that is
essential nesting habitat for this species. However, the survey area is well outside of the apparent geographic
range for the coastal sandiegensis subspecies, which ends around State Route 74 based on CDFW mapping
and distribution descriptions in Rea and Weaver (1990). The local subspecies found throughout Los
Angeles County is C. b. anthonyi, although birds on the coastal slope often show some characteristics of
the sandiegensis subspecies (such as more white in the tail than is otherwise expected for this subspecies).
Environmental Setting
The survey area for this effort encompasses suitable CAGN and CACW habitat within 500 feet of the
existing Canyon Loop Trail. It is located in the southeastern corner of Los Angeles County less than 0.5
mile west of the boundary with San Bernardino County. The survey area represents a small subset of the
entire 500-foot buffer around the Canyon Loop Trail and is approximately 30.24 acres in size. It is generally
associated with preserved open space, although many areas within it, particularly the southeast portion of
it, are disturbed with high proportions of non-native plant species as well. An unnamed ephemeral drainage
runs roughly east to west through the center of the survey area. Areas immediately surrounding the survey
area consist of residential developments to the east and west, and undeveloped land to the north and south.
Canyon Loop Trail Improvement Project 4
Coastal California Gnatcatcher and Cactus Wren Focused Survey Results
Topography and Soils
The topography of the survey area is generally steep slopes with associated public trails along hilltops and
other stabilized surfaces. The survey area is located at an elevation of approximately 970 to 1,310 feet amsl.
According to the Custom Soil Resource Report for Los Angeles County, California, Southeastern Part
(USDA 2020), the survey area is underlain by the following soil units: Urban land-Sorrento-Arbolado
complex, 2 to 9 percent slopes (1136), Gaviota-Chumash-Rock outcrop complex, 20 to 55 percent slopes
(1145), and Counterfeit-Urban land complex, 10 to 35 percent slopes, terraced (1232).
Vegetation Communities
Several terrestrial vegetation communities were identified on-site during the field survey. Vegetation
classification was based on A Manual of California Vegetation (Second Edition) (Sawyer et al. 2009) and
cross-checked with Holland (1986). The vegetation communities and land uses present within the survey
area are depicted on Figure 3, Vegetation Communities, in Attachment A, and described in further detail
below. Figure 3 and the descriptions below only include those communities that are suitable habitat for
CAGN and CACW and do not include all vegetation communities or land uses within 500 feet of the
project. All of the following vegetation communities are associated with what would be considered coastal
sage scrub (CSS) habitat.
California Sagebrush – Black Sage Scrub (Holland Equivalent: Diegan Coastal Sage Scrub; Code: 32500)
Approximately 2.13 acres of California sagebrush – black sage scrub vegetation is located within the survey
area. The majority of this vegetation community is dominated by California sagebrush (Artemisia
californica) and black sage (Salvia mellifera) with other shrubs such as white sage (Salvia apiana),
deerweed (Acmispon glaber), and California buckwheat (Eriogonum fasciculatum) occurring as less
frequent sub-dominants. Due to the high density of shrubs within the vegetation community, little to no
herbaceous cover is present.
Disturbed California Sagebrush – Black Sage Scrub (Holland Equivalent: Disturbed Diegan Coastal Sage
Scrub; Code: 32500)
Approximately 17.76 acres of disturbed California sagebrush – black sage scrub vegetation is located
throughout the survey area. This vegetation community is similar in composition and generally in close
proximity to the California sagebrush – black sage scrub found within the survey area but also contains
black mustard (Brassica nigra) and tocalote (Centaurea melitensis) as co-dominant species, in many areas
completely dominating the ground cover between native shrubs.
California Buckwheat Scrub (Holland Equivalent: Disturbed Diegan Coastal Sage Scrub; Code: 32500)
Approximately 0.45 acre of California buckwheat scrub vegetation is located within the western portion of
the survey area. This vegetation community is entirely dominated by California buckwheat, and appears to
be part of a previous restoration effort.
Coast Prickly Pear Scrub (Holland Equivalent: Diegan Coastal Sage Scrub; Code: 32500)
Approximately 9.90 acres of coast prickly pear scrub vegetation is located within the survey area. Coast
prickly pear (Opuntia littoralis) is dominant within this vegetation community, with sticky monkeyflower
(Diplacus aurantiacus) prominently interspersed throughout the area. California buckwheat and California
sagebrush are also present, but in lower proportions compared to coast prickly pear and sticky
monkeyflower.
Canyon Loop Trail Improvement Project 5
Coastal California Gnatcatcher and Cactus Wren Focused Survey Results
Methods
Literature Review
Prior to conducting the focused surveys, Michael Baker performed a detailed literature review and record
search of the project site, vicinity, and region for CAGN and CACW records. The literature search included
a review of any existing biological and focused CAGN survey reports from the project vicinity, as well as
records reported in the CNDDB (CDFW 2020), the USFWS online Critical Habitat Mapper (USFWS
2020), the Cornell Lab of Ornithology’s eBird database (eBird 2020), and a letter written to the City of
Diamond Bar by Hamilton Biological (Hamilton Biological 2019).
Focused Surveys
Protocol surveys for CAGN and CACW were conducted concurrently along, and in areas of suitable habitat
within 500 feet of, the existing Canyon Loop Trail in 2020. All surveys were conducted by Michael Baker
biologists Ryan Winkleman (USFWS recovery permit TE-88331A-2), Ashley Spencer, and Tom
Millington between May and July 2020 (refer to Table 1, Survey Dates, Surveyors, Time, and Weather
Conditions). The surveys followed the CAGN guidelines described in the USFWS protocol Coastal
California Gnatcatcher (Polioptila californica californica) Presence/Absence Survey Guidelines, February
28, 1997 (USFWS 1997) and the CACW guidelines described in Mr. Winkleman’s CDFW scientific
collecting permit (SC-182750017). A total of six (6) surveys were conducted between May 26 and July 1,
2020.
Table 1: Survey Dates, Surveyors, Time, and Weather Conditions
Date Surveyors Time
(start/finish)
Weather Conditions
Temperature (°F)
(start/finish)
Wind Speed Range
(miles per hour)
5/26/20 Ryan Winkleman 0751 / 1222 64 / 83 0-1
6/3/20 Ryan Winkleman,
Ashley Spencer 0713 / 1146 65 / 87 0-8
6/10/20 Ryan Winkleman,
Ashley Spencer 0720 / 1150 69 / 93 0-3
6/17/20 Ryan Winkleman,
Tom Millington 0729 / 1149 62 / 68 0-1
6/24/20 Ryan Winkleman,
Ashley Spencer 0729 / 1142 62 / 76 0-3
7/1/20 Ryan Winkleman,
Ashley Spencer 0730 / 1130 62 / 67 0-1
During each survey, the biologist(s) walked areas of suitable habitat for CAGN and/or CACW within the
survey area and would stop at strategic locations and use taped playback to attempt to lure the target species
into view. All recordings were obtained from xeno-canto.org (2020) and were played with a Pixel 3XL
smartphone amplified with a MIFA F10 portable Bluetooth speaker. In each instance the biologist(s) would
position themselves in an area of suitable habitat and wait up to one (1) minute to see if the target species
could be incidentally detected. If no birds were detected, Mr. Winkleman would play a short recording or
short portion of a recording, followed by approximately one (1) minute of silence before playing another
Canyon Loop Trail Improvement Project 6
Coastal California Gnatcatcher and Cactus Wren Focused Survey Results
recording or continuing the same recording. Recordings were cycled rather than repeated to more
realistically mimic birds making variable vocalizations. In areas where both species could feasibly be
present, the CAGN and CACW recordings were played alternately. If birds responded aurally or flew into
view, all playback was stopped while the biologist(s) observed the bird(s) from a distance and took notes
on age, sex, and behavior. Territory boundaries were mapped in the Avenza smartphone application while
in the field and updated as necessary to record the approximate boundaries over the six surveys. If nesting
behavior was observed, the biologists watched from a safe distance and, if found, plotted the nest location
as accurately as possible using Global Positioning System (GPS) technology and then watched for updates
on subsequent surveys from a safe distance. Photographs were periodically taken during the surveys (refer
to Figure 2, Survey Area, in Attachment A, as well as to Attachment B).
Results
A total of forty-seven (47) wildlife species were observed within the CAGN survey area during the CAGN
focused surveys including four (4) reptiles, seventy-six (76) birds, and five (5) mammals. A complete list
of wildlife species observed during the focused survey is included in Attachment C.
Coastal California Gnatcatcher
Based on information in the CNDDB (CDFW 2020), eBird (eBird 2020), and from a local expert (Benson
personal communication 2020), CAGN is a rare and local resident in the coastal slope of Los Angeles and
San Bernardino Counties. Populations are somewhat widespread but persistent in the project vicinity in Los
Angeles County, spanning across the Chino Hills, San Jose Hills, and Puente Hills. In San Bernardino
County, which is located immediately to the east of the project site, CAGN persists in only four or five
populations in the entire county, including in Chino Hills State Park. Farther to the south, CAGN is
reasonably common in the foothills of the Santa Ana Mountains in Orange County. The project site is not
located within designated Critical Habitat (USFWS 2007).
A minimum of five (5) CAGN territories were mapped during the focused surveys (refer to Figure 4,
Coastal California Gnatcatcher Results, in Attachment A). Four (4) nests were found in two (2) of these
territories, one (1) of which successfully led to chicks fledging. Of the minimum five territories, four (4)
territories (Territories 1, 3, 4, and 5) had chicks fledge in them. The boundaries of Territories 3 and 5
expanded over time due to post-breeding dispersal, with Territory #5 potentially undergoing two separate
instances of dispersal to two areas where no CAGN had been previously detected. A more detailed summary
of CAGN activity in each territory during each survey is provided in Table 2 below.
Cactus Wren
Similar to CAGN, CACW is a rare and local resident on the coastal slope of Los Angeles and San
Bernardino Counties. In Los Angeles County the species is better off but declining, with populations known
from the Chino Hills, San Jose Hills, Puente Hills, and foothills of the San Gabriel Mountains. In adjacent
San Bernardino County, the only known populations are in the upper Santa Ana River wash near
Redlands/Mentone/Highland and near the confluence of Cajon and Lytle Creeks, both far from the survey
area (Benson personal communication 2020). This species is much more common in Orange County in the
foothills of the Santa Ana Mountains and less so in the San Joaquin Hills. Birds in Los Angeles County are
considered to be of the non-sensitive subspecies C.b. anthonyi, although it should be noted that many of the
birds on the coast, including the ones in the survey area, show characteristics, such as the extent of white
barring in the tail feathers, typically associated with the sensitive CCACW.
Canyon Loop Trail Improvement Project 7
Coastal California Gnatcatcher and Cactus Wren Focused Survey Results
Table 2: CAGN Survey Results
Date Territories
Territory #1 Territory #2 Territory #3 Territory #4 Territory #5
5/26/20 Adult male
present and
foraging
solitarily.
Adult male
present and
foraging,
territorial against
juvenile CACW.
Adult female
briefly observed.
CAGN
incidentally
heard, but not
seen.
Adult male
present and
foraging.
Family unit with two adults
and at least two juveniles
present.
6/3/20 Family unit
with two
adults and two
juveniles
present.
Adult male
present and
foraging,
territorial against
juvenile CACW.
No activity
observed.
Family unit
with at least
one juvenile
present.
Adult male present, no
other birds seen.
6/10/20 Adult male
present with
two female-
type birds,
could not see
well enough to
determine age.
Adult pair
present, Nest #1
found. Male
observed perched
over nest in a
shading action.
Family unit
present with at
least two
juveniles in a
new post-
breeding
dispersal area
where not
previously
found.
Adult pair
present and
foraging, no
other birds
seen.
Adult pair present, Nest #1
found. Both male and
female observed incubating
and shading the eggs.
6/17/20 Adult male
present with a
single female-
type bird, not
aged.
Nest #1 failed.
Adult pair
periodically seen
throughout
territory but no
indications of
nesting.
Family unit in
the post-breeding
dispersal area
again.
Adult male
present and
foraging.
Possible
female seen
but not
confirmed.
Adult pair observed
feeding chicks in Nest #1.
Chicks too small to count
from afar.
6/24/20 Adult male
present with a
single female-
type bird, not
aged.
Adult pair present
and nearly
finished building
Nest #2.
Two female-type
birds present in
the post-breeding
dispersal area,
including the
adult female
carrying off
food.
Adult male
present and
foraging.
Adult pair present feeding
chicks in Nest #1. Four
chicks visible in nest. Two
juvenile birds found to the
north, up the hillside above
the territory in mustard,
assumed to be the juveniles
from 5/26 in a post-
breeding dispersal area,
although not previously
found here despite weekly
playback.
7/1/20 Four birds
flew in
together to
playback and
then went out
of sight. Later
observed the
adult pair
bringing food
to juveniles.
Nest #2 failed.
Adult male
observed building
a new nest, Nest
#3.
One bird heard-
only, one
female-type bird
briefly seen in
the post-breeding
dispersal area.
Adult male
present and
foraging.
Nest #1 empty and nesting
territory abandoned. Four
birds, including at least one
adult (male), found in the
6/24 post-breeding
dispersal area. Up to three
separate birds found
approximately 250 meters
to the east. Possibly more
Territory #5 dispersal.
Canyon Loop Trail Improvement Project 8
Coastal California Gnatcatcher and Cactus Wren Focused Survey Results
A total of five (5) CACW territories were mapped during the focused surveys (refer to Figure 5, Cactus
Wren Results, in Attachment A). No attempts were made to find CACW nests, although one (1) nest was
incidentally found outside of any apparently active territories. Although no nests were found in the
territories, all five territories fledged young. Of these, Territory #5 is the only one that had an obvious
instance of post-breeding dispersal into a new area during the surveys, with all other families utilizing the
same territories that they had evidently nested in. A more detailed summary of CACW activity in each
territory during each survey is provided in Table 3 below.
Table 3: CACW Survey Results
Date Territories
Territory #1 Territory #2 Territory #3 Territory #4 Territory #5
5/26/20 Adult pair
present.
Independent
juvenile bird to
the west either
from Territory
#1 or Territory
#3.
Adult male
singing.
Adult pair
present.
Adult pair with
two juveniles
present.
One bird heard only.
Cooper’s hawk
suppressed activity.
6/3/20 Adult pair
present.
Independent
juvenile bird to
the west either
from Territory
#1 or Territory
#3.
Adult male
singing.
Adult bird
present.
At least three
birds present.
Food exchange
witnessed
between adult
and one of the
juveniles.
One bird heard only.
Cooper’s hawk
suppressed activity.
6/10/20 Two adults
present.
Three adults
and one
juvenile
present.
Adult male
singing.
Two adults and
two juveniles
present.
Two adults and two
juveniles present
together.
6/17/20 Two adults and
three juveniles
present.
Two adults and
two juveniles
present.
Adult male
singing.
At least four
birds present.
Family unit moved
slightly north to a post-
breeding dispersal area.
6/24/20 One bird present,
did not take
notes on age.
Three birds
present, did not
take notes on
age.
Two adults
present.
Five birds
present
together.
All four birds seen
together in the post-
breeding dispersal area.
7/1/20 Two adults seen
in territory.
All four birds
seen in
territory.
One adult with
two juveniles
observed. First
evidence of
nesting.
Five birds
present in a
group together.
No birds found in the
post-breeding dispersal
area. Two adults and one
juvenile found in the
original territory.
Conclusions and Recommendations
Based on the results of the focused surveys, at least five (5) CAGN and five (5) CACW territories were
found to be present within the 500-foot survey area. Four (4) CAGN pairs and all five (5) CACW pairs
Canyon Loop Trail Improvement Project 9
Coastal California Gnatcatcher and Cactus Wren Focused Survey Results
successfully fledged young in 2020 as evidenced by firsthand observations by Michael Baker biologists
during the surveys. Many of the territories were directly adjacent to, crossed over, or were at least in close
proximity to proposed trail improvement areas. Of the nests that were found, the closest nest (CAGN
Territory #2 Nest #1) was approximately 70 feet from the Canyon Loop Trail.
Although a variety of trail improvements are proposed for this project, most of the improvements are
widening the existing trail in the southern half of the survey area. This would result in loss of suitable
habitat for these species, particularly for CAGN. Based on project plans, the length of proposed trail
widening is currently estimated at approximately 1,942 feet, or approximately 0.37 mile. The trail is
proposed to be widened to five feet total width, which means on average based on field observations during
the surveys it would be widened an additional one to two feet from its current width at these locations. The
on-site CACW is not believed to be the sensitive CCACW protected by the CDFW as a SSC; regardless,
impacts to this species can be addressed through a nesting bird clearance survey (see below), with additional
benefits imparted via CAGN protections. Although this area is not designated as Critical Habitat, loss of
vegetation directly supporting known populations of CAGN would constitute “take” of CAGN under
Section 9 of the FESA. Because the project will not have a Federal nexus to allow for FESA Section 7
consultations, an incidental take permit (ITP) would instead be granted by the USFWS under Section
10(a)(1)(B) of the FESA. This typically entails the project proponent agreeing to a habitat conservation
plan (HCP), an extensive process that can take years to complete. However, the USFWS also has a category
of HCPs for projects that will otherwise have minor impacts on listed species, called a “low-effect HCP.”
These HCPs pertain to projects involving (1) minor or negligible effects on federally listed, proposed, or
candidate species and their habitats covered under the HCP; and (2) minor or negligible effects on other
environmental values or resources. Under low-effect HCPs, the permitting process is more streamlined and
take can generally be authorized under a series of strict avoidance and minimization measures. Therefore,
it is recommended that the City consult with USFWS and pursue a low-effect HCP to permit removal of
habitat suitable for and/or used by CAGN on the project site.
To avoid indirect impacts and take of CAGN or CACW, it is recommended that all project-related
construction occur outside of the general breeding season (February 15 – September 15). Timing the
construction to be outside of this window of time would avoid impacts to CAGN or CACW nests. If it is
not possible to construct the project outside of this time period, it is recommended that a nesting bird survey
be conducted within seven (7) days prior to the start of construction in a 500-foot buffer from the project.
The survey should be conducted by a qualified biologist with demonstrable experience identifying CAGN
and CACW nesting behavior and finding their nests, and who has been approved by the USFWS to conduct
a CAGN nesting survey. If an active CAGN or CACW nest is found during the survey, no project-related
construction will be allowed within 500 feet of an active CAGN nest or 300 feet of an active CACW nest,
or within an alternative safe distance as determined by the qualified biologist based on topography, visual
shielding, nest progress, and the type of construction and associated disturbance, until the active nest has
been determined by the qualified biologist to have failed or to have successfully gone to completion (i.e.
the nestlings have fledged and are no longer reliant on the nest). Results of the nesting bird survey, should
one be required, shall be compiled in a memorandum and submitted to the City and to the USFWS for the
project record.
Please do not hesitate to contact me at (949) 533-0918 or ryan.winkleman@mbakerintl.com should you
Canyon Loop Trail Improvement Project 10
Coastal California Gnatcatcher and Cactus Wren Focused Survey Results
have any questions or require further information regarding the information presented in this report.
Sincerely,
Ryan Winkleman
Senior Biologist
Natural Resources and Regulatory Permitting
Attachments:
A. Figures
B. Site Photographs
C. Wildlife Species Observed List
D. References
Attachment A
Figures
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LOS ANGELES COUNTY
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Regional Vicinity
Figure 1
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Miles7/30/2020 JN H:\pdata\178669\GIS\MXD\Focused Bird Surveys\Fig 01 Regional Vicinity.mxd RPCANYON LOOP TRAIL IMPROVEMENT PROJECT
COASTAL CALIFORNIA GNATCATCHER AND CACTUS WREN FOCUSED SURVEY RESULTS
Source: ArcGIS Online, 2018
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Survey Area7/30/2020 JN H:\pdata\178669\GIS\MXD\Focused Bird Surveys\Fig 02 Survey Area.mxd RPSource: Nearmap, 2020 Figure 2
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CANYON LOOP TRAIL IMPROVEMENT PROJECT
COASTAL CALIFORNIA GNATCATCHER AND CACTUS WREN FOCUSED SURVEY RESULTS
°
Legend
Project Site
Survey Area
(Suitable Habitat
within 500 Feet)"Photograph Point
and Direction
!>Reference Point
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Vegetation Communities7/30/2020 JN H:\pdata\178669\GIS\MXD\Focused Bird Surveys\Fig 03 Vegetation Communities.mxd RPSource: Nearmap, 2020 Figure 3
0 270135
Feet
CANYON LOOP TRAIL IMPROVEMENT PROJECT
COASTAL CALIFORNIA GNATCATCHER AND CACTUS WREN FOCUSED SURVEY RESULTS
°
Legend
Project Site
Survey Area
(Suitable Habitat
within 500 Feet)
California Buckwheat
Scrub (0.45 acre)
California Sagebrush -
Black Sage Scrub
(2.13 acres)
Coast Prickly Pear
Scrub (9.90 acres)
Disturbed California
Sagebrush - Black
Sage Scrub
(17.76 acres)
Unnamed Drainage
!>Reference Point
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34.007148-117.794138
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Coastal California Gnatcatcher Results8/4/2020 JN H:\pdata\178669\GIS\MXD\Focused Bird Surveyst\Fig 04 Coastal California Gnatcatcher Results.mxd RPSource: Nearmap, 2020 Figure 4
0 270135
Feet
CANYON LOOP TRAIL IMPROVEMENT PROJECT
COASTAL CALIFORNIA GNATCATCHER AND CACTUS WREN FOCUSED SURVEY RESULTS
°
Legend
Project Site
Survey Area
(Suitable Habitat
within 500 Feet)
!>Reference Point
CAGN Territories
Territory #1
Territory #2
Territory #3
Territory #3
(Post-breeding
Dispersal)
Territory #4
Territory #5
Territory #5
(Post-breeding
Dispersal)
CAGN Nests
!(Successful Nest
!(Failed Nest
Proposed Trail Improvements
Trail to be Expanded
to 5' Wide
Existing Trail to Remain
Gabion Retaining Wall
Stairs
kj Wayfinding Sign
Lodge Pole Fence
(Shade Structure with
Benches & Trash Receptacle
Proposed Bench
Drainage Crossing
!(!(
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6/3/20
34.007148-117.794138
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0 270135
Feet
CANYON LOOP TRAIL IMPROVEMENT PROJECT
COASTAL CALIFORNIA GNATCATCHER AND CACTUS WREN FOCUSED SURVEY RESULTS
°
Legend
Project Site
Survey Area
(Suitable Habitat
within 500 Feet)
!>Reference Point
CACW Territories
Territory #1
Territory #2
Territory #3
Territory #4
Territory #5
Territory #5
(Post-breeding
Dispersal)
CACW Nests
!(Old Nest
CACW Observations
!(Solitary Juvenile
Proposed Trail Improvements
Trail to be Expanded
to 5' Wide
Existing Trail to Remain
Gabion Retaining Wall
Stairs
kj Wayfinding Sign
Lodge Pole Fence
(Shade Structure with
Benches & Trash Receptacle
Proposed Bench
Drainage Crossing
!(!(
Attachment B
Site Photographs
Attachment B – Site Photographs
Canyon Loop Trail Improvement Project B-1
Coastal California Gnatcatcher and Cactus Wren Focused Survey Results
Photograph 1: Standing in coastal California gnatcatcher (CAGN) Territory 1 facing
east-northeast.
Photograph 2: Standing in the CAGN Territory 2 facing south-southeast.
Attachment B – Site Photographs
Canyon Loop Trail Improvement Project B-2
Coastal California Gnatcatcher and Cactus Wren Focused Survey Results
Photograph 3: Standing in CAGN Territory 2 facing southwest. This is the most
highly-disturbed CAGN territory within the survey area.
Photograph 4: Standing in CAGN Territory 2 facing northeast.
Attachment B – Site Photographs
Canyon Loop Trail Improvement Project B-3
Coastal California Gnatcatcher and Cactus Wren Focused Survey Results
Photograph 5: Standing in CAGN Territory 3 facing southeast.
Photograph 6: Standing in CAGN Territory 3 facing west.
Attachment B – Site Photographs
Canyon Loop Trail Improvement Project B-4
Coastal California Gnatcatcher and Cactus Wren Focused Survey Results
Photograph 7: Standing in CAGN Territory 4 facing southeast.
Photograph 8: Standing in CAGN Territory 4 facing southwest.
Attachment B – Site Photographs
Canyon Loop Trail Improvement Project B-5
Coastal California Gnatcatcher and Cactus Wren Focused Survey Results
Photograph 9: Standing in CAGN Territory 5 facing northeast.
Photograph 10: Standing in CAGN Territory 5 facing west.
Attachment B – Site Photographs
Canyon Loop Trail Improvement Project B-6
Coastal California Gnatcatcher and Cactus Wren Focused Survey Results
Photograph 11: Facing west toward cactus wren (CACW) Territory 1.
Photograph 12: Facing north toward CACW Territory 2.
Attachment B – Site Photographs
Canyon Loop Trail Improvement Project B-7
Coastal California Gnatcatcher and Cactus Wren Focused Survey Results
Photograph 13: Standing in CACW Territory 3 facing south.
Photograph 14: Standing in CACW Territory 4 facing west.
Attachment B – Site Photographs
Canyon Loop Trail Improvement Project B-8
Coastal California Gnatcatcher and Cactus Wren Focused Survey Results
Photograph 15: Facing northeast toward CACW Territory 5.
Photograph 16: An adult male CAGN acts aggressively toward a lone juvenile CACW
in CAGN Territory #2.
Attachment B – Site Photographs
Canyon Loop Trail Improvement Project B-9
Coastal California Gnatcatcher and Cactus Wren Focused Survey Results
Photograph 17: A CACW family gathers together in CACW Territory 5.
Photograph 18: An adult male CAGN brings food for the waiting nestlings in Territory
5 Nest #1.
Attachment C
Wildlife Species Observed List
Attachment C –Wildlife Species Observed List
Canyon Loop Trail Improvement Project C-1
Coastal California Gnatcatcher and Cactus Wren Focused Survey Results
Table C-1: Wildlife Species Observed List
Scientific Name* Common Name Special-Status Rank**
Reptiles
Aspidoscelis tigris stejnegeri coastal whiptail SSC
Coluber flagellum piceus red racer
Sceloporus occidentalis longipes Great Basin fence lizard
Uta stansburiana elegans western side-blotched lizard
Birds
Accipiter cooperii Cooper’s hawk WL
Aeronautes saxatalis white-throated swift
Aimophila ruficeps canescens southern California rufous-crowned sparrow WL
Aphelocoma californica California scrub jay
Baeolophus inornatus oak titmouse
Buteo jamaicensis red-tailed hawk
Callipepla californica California quail
Calypte anna Anna’s hummingbird
Campylorhynchus brunneicapillus cactus wren
Cathartes aura turkey vulture
Chamaea fasciata wrentit
Contopus sordidulus western wood-pewee
Corvus brachyrhynchos American crow
Corvus corax common raven
Dryobates nuttallii Nuttall’s woodpecker
Empidonax difficilis pacific-slope flycatcher
Geococcyx californianus greater roadrunner
Haemorhous mexicanus house finch
Icterus cucullatus hooded oriole
Leiothlypis celata orange-crowned warbler
Melanerpes formicivorus acorn woodpecker
Melozone crissalis California towhee
Mimus polyglottos northern mockingbird
Molothrus ater brown-headed cowbird
Myiarchus cinerascens ash-throated flycatcher
Patagioenas fasciata band-tailed pigeon
Petrochelidon pyrrhonota cliff swallow
Phainopepla nitens phainopepla
Pipilo maculatus spotted towhee
Polioptila caerulea blue-gray gnatcatcher
Polioptila californica californica coastal California gnatcatcher FT/SSC
Psaltriparus minimus bushtit
Sayornis nigricans black phoebe
Sayornis saya Say’s phoebe
Selasphorus sasin Allen’s hummingbird
Attachment C –Wildlife Species Observed List
Canyon Loop Trail Improvement Project C-2
Coastal California Gnatcatcher and Cactus Wren Focused Survey Results
Table C-1: Wildlife Species Observed List
Scientific Name* Common Name Special-Status Rank**
Sitta carolinensis white-breasted nuthatch
Spinus lawrencei Lawrence’s goldfinch
Spinus psaltria lesser goldfinch
Stelgidopteryx serripennis northern rough-winged swallow
Thryomanes bewickii Bewick’s wren
Toxostoma redivivum California thrasher
Troglodytes aedon house wren
Turdus migratorius American robin
Tyrannus verticalis western kingbird
Tyrannus vociferans Cassin’s kingbird
Vireo huttoni Hutton’s vireo
Zenaida macroura mourning dove
Mammals
Neotoma sp. woodrat
Odocoileus hemionus mule deer
Otospermophilus beecheyi California ground squirrel
Sciurus niger* eastern fox squirrel
Sylvilagus audubonii desert cottontail
* Non-native species
** Special-Status Rank
FT Federally Threatened
SSC Species of Special Concern – any species, subspecies, or distinct population of fish, amphibian, reptile, bird,
or mammal native to California that currently satisfies one or more of the following criteria:
- is extirpated from California or, in the case of birds, in its primary seasonal or breeding role;
- is listed as Federally-, but not State-, threatened or endangered; meets the State definition of
threatened or endangered but has not formally been listed.
- is experiencing, or formerly experienced, serious (noncyclical) population declines or range
retractions (not reversed) that, if continued or resumed, could qualify it for State threatened or
endangered status; or
- has naturally small populations exhibiting high susceptibility to risk from any factor(s), that if
realized, could lead to declines that would qualify it for State threatened or endangered status.
WL Watch List - taxa that were previously designated as “Species of Special Concern” but no longer merit that
status, or which do not yet meet SSC criteria, but for which there is concern and a need for additional
information to clarify status.
Attachment D
References
Attachment D – References
Canyon Loop Trail Improvement Project D-1
Coastal California Gnatcatcher and Cactus Wren Focused Survey Results
Benson, T.A. 2020. Personal communication regarding the regional status of coastal California gnatcatcher
and cactus wren. California State University at San Bernardino, Instructional Support Technician.
July 21, 2020.
California Department of Fish and Wildlife (CDFW). 2020. RareFind 5, California Natural Diversity Data
Base, California. Data base report on threatened, endangered, rare or otherwise sensitive species
and communities for Los Angeles, San Bernardino, and Orange Counties.
eBird. 2020. eBird: An online database of bird distribution and abundance [web application]. eBird, Cornell
Lab of Ornithology, Ithaca, New York. Accessed online at: http://www.ebird.org.
Hamilton Biological. 2019. CEQA Review, Canyon Loop Trail Project, City of Diamond Bar. Submitted to
the City of Diamond Bar. October 14, 2019.
Holland, R. 1986. Preliminary Descriptions of the Terrestrial Natural Communities of California.
Rea, A.M. and K.L. Weaver. 1990. The Taxonomy, Distribution, and Status of Coastal Cactus Wrens.
Western Birds 21(3): 81-126.
Sawyer, J.O., Keeler-Wolf, T., and J. Evens. 2009. A Manual of California Vegetation (Second Edition).
California Native Plant Society, Sacramento, California, USA.
Shuford, W. D., and Gardali, T., editors. 2008. San Diego Cactus Wren. In California Bird Species of
Special Concern: A ranked assessment of species, subspecies, and distinct populations of birds of
immediate conservation concern in California. Studies of Western Birds 1. Western Field
Ornithologists, Camarillo, California, and California Department of Fish and Game, Sacramento.
U.S. Department of Agriculture, Natural Resources Conservation Service (USDA). 2020. Custom Soil
Resource Report for Los Angeles County, California, Southeastern Part. Accessed online at:
http://websoilsurvey.nrcs.usda.gov/app/.
U.S. Fish and Wildlife Service (USFWS). 1997. Coastal California Gnatcatcher (Polioptila californica
californica) Presence/Absence Survey Guidelines. February 28, 1997.
U.S. Fish and Wildlife Service (USFWS). 2007. Endangered and Threatened Wildlife and Plants; Revised
Designation of Critical Habitat for the Coastal California Gnatcatcher (Polioptila californica
californica). Federal Register 72(243): 72010-72213.
U.S. Fish and Wildlife Service (USFWS). 2010. Coastal California Gnatcatcher (Polioptila californica
californica) 5- Year Review: Summary and Evaluation. Accessed online at:
https://www.fws.gov/carlsbad/SpeciesStatusList/5YR/20100929_5YR_CAGN.pdf.
U.S. Geological Survey. 1981. San Dimas, California 7.5-Minute Topographic Quadrangle Map.
xeno-canto. 2020. xeno-canto: sharing bird sounds from around the world. Accessed online at:
http://www.xeno-canto.org.
Attachment C
References
Attachment C – References
Canyon Loop Trail Improvement Project C-1
Coastal California Gnatcatcher Memo
California Department of Fish and Wildlife (CDFW). 2021. California Natural Community List. Last
updated August 18, 2021.
eBird. 2022. eBird: An online database of bird distribution and abundance [web application]. eBird, Cornell
Lab of Ornithology, Ithaca, New York. Accessed online at: http://www.ebird.org.
U.S. Fish and Wildlife Service (USFWS). 1997. Coastal California Gnatcatcher (Polioptila californica
californica) Presence/Absence Survey Guidelines. February 28, 1997.
USFWS. 2007. Endangered and Threatened Wildlife and Plants; Revised Designation of Critical Habitat
for the Coastal California Gnatcatcher (Polioptila californica californica). Federal Register
72(243): 72010-72213.
USFWS. 2010. Coastal California Gnatcatcher (Polioptila californica californica) 5- Year Review:
Summary and Evaluation. Accessed online at:
https://www.fws.gov/carlsbad/SpeciesStatusList/5YR/20100929_5YR_CAGN.pdf.