In Reply Refer to: FWS-SB-19B0147-19F1274

October 23, 2019 Sent by Email

Antal Szijj Team Lead, North Coast Branch Regulatory Division, Los Angeles District U.S. Army Corps of Engineers 60 S. California Street, Suite 201 Ventura, California 93001-2598

Michael P. Kelly Counsel, Base Realignment and Closure Office of the Deputy General Counsel (Installations, Energy and Environment) 3411 Olson Street McClellan, California 95652-1003

Subject: Biological Opinion for the Issuance of an Incidental Take Permit for the High Desert Solar Project, San Bernardino County, California

Dear Mr. Szijj and Mr. Kelly:

Enclosed please find the final biological opinion for the U.S. Fish and Wildlife Service’s (Service) issuance of an incidental take permit, pursuant to section 10(a)(1)(B) of the Endangered Species Act of 1973, as amended, for the High Desert Solar Project. The Service completed this biological opinion as part of its internal process of evaluating the incidental take permit application from HDSI, LLC. This biological opinion also responds to the U.S. Army Corps of Engineers’ request for formal consultation, dated June 10, 2019, for its proposed authorization of the project, pursuant to section 404 of the Clean Water Act.

During informal consultation on the proposed action, The U.S. Air Force notified the Service that it intended to reply on the Service as the lead Federal agency for compliance with section 7(a)(2) of the Endangered Species Act, pursuant to 50 Code of Federal Regulations (CFR) 402.07. We are providing you with a copy of the biological opinion for your records.

We appreciate your cooperation and coordination during this consultation and that of your staff, (Emma Ross, Army Corps of Engineers) and Molly Enloe (Air Force). If you have any questions, please contact Ray Bransfield of my staff at (805) 677-3398 or ray_bransfield@fws.gov.

Sincerely,

Scott A. Sobiech Field Supervisor

Enclosure

In Reply Refer to: FWS-SB-19B0147-19F1274

October 23, 2019Sent by Email

Memorandum

To: Field Supervisor, Carlsbad Fish and Wildlife Office, Carlsbad, California

From: Acting Assistant Field Supervisor, Palm Springs Fish and Wildlife Office, Palm Springs, California

Subject: Intra-Service Consultation on the Issuance of a Section 10(a)(1)(B) Permit for the High Desert Solar Project, San Bernardino County, California

This document transmits the U.S. Fish and Wildlife Service’s (Service) biological opinion regarding the High Desert Solar Project. We prepared the document in accordance with section 7(a)(2) of the Endangered Species Act of 1973 (Act), as amended (16 U.S.C. 1531 et seq.).

We are considering two Federal actions in this biological opinion with regard to the proposed High Desert Solar Project (project). First, we will consider the effects of the Service’s proposed issuance of an incidental take permit to HDSI, LLC (HDSI), pursuant to section 10(a)(1)(B) of the Act, for the federally threatened desert tortoise [Mojave population distinct population segment (Gopherus agassizii)]. We will also consider the effects of the U.S. Army Corps of Engineers’ (Corps 2019) proposed authorization of the project, pursuant to section 404 of the Clean Water Act. We received the Army’s request for formal consultation on June 10, 2019.

We based this biological opinion on information in the final habitat conservation plan for the project (AECOM 2019) and information in our files. We can make a record of this consultation available at the Carlsbad Fish and Wildlife Office.

CONSULTATION HISTORY

A portion of the generator tie-in line for the project crosses an area of the former George Air Force Base (AECOM 2019, Figure 1-2). The U.S. Air Force continues to own and manage this land; therefore, it is considering the sale of an easement to HDSI for the construction and operation of the generator tie-in line. The Air Force intends to dispose of these lands in the future, as part of the complete disposal of the former George Air Force Base.

BRIAN CROFT Digitally signed by BRIAN CROFT Date: 2019.10.23 11:11:05 -07'00'

Enclosure

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Because the Air Force intends to dispose of the lands within a few years and the term of the incidental take permit is 35 years, the Service, Air Force, and HDSI agreed that HDSI would be responsible for monitoring required for the desert tortoise with regard to the generator tie-in line on Air Force lands. HDSI will continue to monitor the generator tie-in line after their disposal. Consequently, the Air Force notified the Service via electronic mail that it was designating the Service as the lead Federal agency for completion of section 7(a)(2) consultation, pursuant to 50 Code of Federal Regulations (CFR) 402.07.

The proposed project site is not within critical habitat of the desert tortoise. The translocation site and mitigation lands are within critical habitat. During translocation, biologists will drive on existing routes that the Bureau of Land Management (Bureau) has designated as open, park in previously disturbed areas, and walk through habitat to release points. They will not dig artificial burrows for released desert tortoises.

During monitoring and restoration of the mitigation lands, biologists will drive on existing routes that the Bureau has designated as open, park in previously disturbed areas, and walk through habitat to monitor site conditions, restore disturbed habitat, and remove non-native plants.

We have listed the physical and biological features of critical habitat of the desert tortoise and provided our rationale for why the translocation of desert tortoises and management of the mitigation lands area are not likely to adversely affect critical habitat of the desert tortoise.

Sufficient space to support viable populations within each of the six recovery units and to provide for movement, dispersal, and gene flow: Driving on open routes, walking through habitat, monitoring site conditions, and removing non-native plants will not reduce space to support viable populations or impede movement, dispersal, and gene flow. These activities will not remove habitat or construct any barriers to movement.

Sufficient quality and quantity of forage species and the proper soil conditions to provide for the growth of these species: Forage species and the appropriate soil conditions are frequently absent from open routes, previously disturbed areas, and areas in need of restoration. Walking through habitat is likely to temporarily disturb forage plants and substrate but we consider these effects insignificant.

Suitable substrates for burrowing, nesting, and overwintering: This physical and biological feature is generally absent from open routes and disturbed areas that require restoration. Walking through habitat will not affect the quality of substrates for burrowing, nesting, and overwintering.

Burrows, caliche caves, and other shelter sites: This physical and biological feature is generally absent from open routes and disturbed areas that require restoration. Walking through habitat will not affect burrows, caliche caves, and other shelter sites.

Sufficient vegetation for shelter from temperature extremes and predators: Shrubs that provide shelter for desert tortoises are generally absent from open routes and disturbed areas that require restoration. Walking through habitat will not affect this physical and biological feature.

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Habitat protected from disturbance and human-caused mortality: The activities at the translocation and mitigation sites will cause minor, temporary disturbance; we consider this level of disturbance insignificant. The activities will not increase the likelihood of human-caused mortality.

For these reasons, the Service has concluded that the proposed action is not likely to adversely affect critical habitat of the desert tortoise. We will not discuss critical habitat again in this biological opinion.

On September 25, 2019, we provided a draft of this biological opinion to the Air Force and Corps for review. Both the Air Force (Kelly 2019) and Corps (Ross 2019) reviewed the draft and responded that they had no concerns or comments regarding its content.

BIOLOGICAL OPINION

DESCRIPTION OF THE PROPOSED ACTION

Solar Facility and Ancillary Features

The Service’s issuance of an incidental take permit would allow for the incidental take of desert tortoises during the construction, operation, maintenance, and decommissioning of the High Desert Solar Project; the incidental take permit would also address the translocation of desert tortoises to an off-site area and management of mitigation lands. The Corps’ authorization would encompass approximately 0.0379 acre (789 linear feet) of permanent impacts and approximately 0.34 acre (4,953 linear feet) of temporary impacts to waters of the United States. The Corps’ scope of analysis includes a 50-foot buffer surrounding both areas to account for direct impacts from work within waters. The Corps’ (2019) request for formal consultation contains maps of the waters of the United States.

The proposed High Desert Solar Project consists of a 108-megawatt solar photovoltaic power-generating facility on approximately 581 acres of privately owned lands within the City of Victorville. The project would include the field of solar panels, an integrated battery energy storage system, an onsite electrical substation, and external roads to access the site. The solar field would interconnect with Southern California Edison’s 230-kilovolt transmission line to the south of the site via a 2.3-mile-long generator tie-in line. A 12.47- kilovolt service line would connect to the Victorville Municipal Utility Services electrical system southwest of the solar field area; the service line would be approximately 1.7 miles long. We will refer to these lines as the power lines when discussing both lines. Figure 1-2 in the habitat conservation plan depicts the components of the proposed project; the habitat conservation plan also provides a more detailed description of the proposed project (AECOM 2019). We are incorporating the habitat conservation plan by reference.

Construction of the project would involve moving materials to the site via public roads from U.S. Highway 395, installation of a fence around the site, and installation of the various components of the solar field and ancillary facilities; HDSI may need to repair the access road between the

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site and Highway 395. Construction of the power lines would include moving materials to the site via public roads from U.S Highway 395, improvement of unpaved access roads along the proposed easements, the use of lay-down areas, and standard construction of the transmission towers and stringing of the power lines. The temporary improvement of unpaved construction and maintenance access roads along the generator tie-in line would involve work within waters of the United States.

Operation and maintenance of the solar facility would generally involve periodic inspections of the facilities within the fenced solar field, the perimeter fence, and power lines and HDSI’s implementation of any needed repairs. Decommissioning would involve removing components of the project, including interconnections, off-site to either an approved landfill or a recycling facility.

Measures to Minimize and Mitigate the Incidental Take of Desert Tortoises

HDSI developed the minimization and mitigation programs in coordination with the Service and California Department of Fish and Wildlife (Department). The habitat conservation plan contains a detailed description of these programs.

Minimization Measures

Table 2-1 of the habitat conservation plan lists the minimization measures that HDSI will implement during the term of the incidental take permit. The measures are generally similar to those used for large projects within the range of the desert tortoise. These measures include, but are not limited to:

1. Educating all personnel regarding the desert tortoise and the protective measures that are in place during all phases of the project;

2. Marking work areas with stakes and flagging to delineate the boundaries of construction areas;

3. Requiring project vehicles to stay within the project’s rights-of-way;

4. Implementing best management practices for stock-piling of soils, control of erosion, fueling and maintenance of vehicles, and control of weeds;

5. Monitoring of work activities outside of fenced areas by authorized biologists;

6. Fencing of the solar facility prior to the onset of construction to prevent desert tortoises from entering it;

7. Containment of trash to reduce the attractiveness of the site to predators of desert tortoises; and

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Translocation of desert tortoises from the project area to suitable habitat off-site. Throughout this biological opinion, we will refer to area of the proposed solar field and power lines as the “project area;” we use the phrase “action area” to mean the project area, recipient site, and mitigation site. We describe the action area in more detail in the Action Area section of this biological opinion.

Translocation - HDSI has proposed to translocate all desert tortoises it finds in the project area to lands managed by the Bureau approximately 18 miles north of the High Desert Solar Project (AECOM 2019, section 1.4). If these lands become unavailable for some reason, HDSI has proposed several other sites as substitutes. We will not discuss these other sites in detail in this biological opinion; however, we consider the potential selection of alternative sites for translocation to be an appropriate strategy for adaptive management.

In general, HDSI has proposed to follow the Service’s (2018a) recommended draft guidance for the translocation of desert tortoises. To ensure that desert tortoises have the greatest opportunity to adapt to the translocation area, HDSI has proposed to:

1. Conduct a visual health assessment of desert tortoises from the project site, prior to their release, to ensure they are in good condition for translocation and are unlikely to transmit diseases to animals that are resident in the recipient area;

2. Release desert tortoises at a time of year and in weather conditions that are unlikely to exacerbate stresses related to translocation;

3. Release desert tortoises in areas with appropriate shelters, such as burrows, caliche caves, washes, or substantial shrub cover; and

4. Release desert tortoises in areas away from resident animals with which they may have negative interactions.

The translocation plan (ECORP Consulting [ECORP] 2019) contains a detailed description of the manner in which HDSI proposes to implement the translocation. We are incorporating the translocation plan by reference. The Department may require additional measures in its incidental take permit, such as disease testing of desert tortoises from the project site and the attachment of transmitters to the translocated desert tortoises. Because HDSI will use only qualified biologists approved by the Service who will follow our protocols for these procedures, these activities are not likely to adversely affect desert tortoises and we will not discuss them further in this biological opinion.

The seasonal timing of translocation is an important component in its success. In the event that HDSI cannot translocate desert tortoises at the appropriate time of the year (i.e., the spring and fall active seasons), it will employ authorized biologists to attach radio transmitters to the desert tortoises. HDSI would then be able to avoid desert tortoises during construction until the time of year is appropriate for translocation.

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Regional Raven Management Funding - Even with thorough implementation of measures to reduce its attractiveness to common ravens, the project’s power lines, fences, and other structures remain likely to provide subsidies in the form of perches, nest sites, and food (i.e., through birds that collide with the power lines and fences). For this reason, HDSI will contribute approximately $59,640 ($105 per acre for the estimated permanent disturbance of 568 acres) to the regional management and monitoring program for the common raven in the California Desert Conservation Area. Numerous agencies in the California desert established this program to address the regional threat that increased numbers of common ravens pose to the desert tortoise. The National Fish and Wildlife Foundation maintains the funds, which the partner agencies, including the Service, use to monitor the number of common ravens throughout conservation areas for the desert tortoise, control common ravens that prey on desert tortoises, monitor the effectiveness of management techniques, and cooperate on research and development of additional tools to reduce this predation risk. The Service (2011) defined “conservation areas” for the desert tortoise in its revised recovery plan. The Status of the Species - Recovery Plan section of this biological opinion provides a description of conservation areas within the specific context of the recovery of the desert tortoise.

Mitigation Measures

One of the issuance criteria for a section 10(a)(1)(B) permit is that the applicant must mitigate the effects of the take to the maximum extent practicable. For the proposed project, HDSI will acquire approximately 568 acres of suitable habitat within a conservation area for the desert tortoise. The actual acreage of the acquisition may be slightly more or less than 568 acres, because of parcel boundaries.

HDSI will establish a non-wasting endowment to fund the long-term management of the mitigation lands. This management may include, but is not limited to, “enhancement of disturbed habitat, removal of trash, and protection from unauthorized uses” (AECOM 2019). HDSI has proposed to use adaptive management and coordinate with the land manager and Service if the land manager needs to conduct additional activities to ensure the mitigation lands are functioning properly.

Reporting

1. HDSI will submit an annual report to the Service that includes, at least, the following information:

2. A summary of the status of biological goals and objectives of the habitat conservation plan;

3. A description of covered activities and associated minimization measures implemented during the reporting period;

4. An assessment of the effectiveness of reducing effects to the desert tortoise and a discussion and explanation of any minimization measures that may need modification;

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5. A summary of observations of desert tortoise including a map showing the locations of the observations and completed forms submitted to the California Natural Diversity Database;

6. A year-to-date and cumulative summary of effects (in acres) to desert tortoise habitat and any documented incidental take of desert tortoises;

7. A year-to-date and cumulative summary of mitigation actions and summary of effectiveness monitoring of mitigation;

8. A description of circumstances that made adaptive management necessary, documentation of discussions with the Service, and a description of how HDSI or the land manager implemented adaptive management;

9. A description of any changed or unforeseen circumstances that occurred and how they were addressed; and

10. A description of any minor or major amendments.

ANALYTICAL FRAMEWORK FOR THE JEOPARDY DETERMINATION

Section 7(a)(2) of the Endangered Species Act requires that Federal agencies ensure that any action they authorize, fund, or carry out is not likely to jeopardize the continued existence of listed species. “Jeopardize the continued existence of” means to engage in an action that reasonably would be expected, directly or indirectly, to reduce appreciably the likelihood of both the survival and recovery of a listed species in the wild by reducing the reproduction, numbers, or distribution of that species (50 CFR 402.02).

The jeopardy analysis in this biological opinion relies on four components: (1) the Status of the Species, which describes the range-wide condition of the species, the factors responsible for that condition, and its survival and recovery needs; (2) the Environmental Baseline, which describes the condition of the species in the action area, the factors responsible for that condition, and the relationship of the action area to the survival and recovery of the species; (3) the Effects of the Action, which are all consequences to listed species caused by the proposed action that are reasonably certain to occur; and (4) the Cumulative Effects, which evaluate the effects of future, non-Federal activities in the action area on the species that are reasonably certain to occur.

For the section 7(a)(2) determination regarding jeopardizing the continued existence of the species, the Service begins by evaluating the effects of the proposed Federal action and the cumulative effects. The Service then examines those effects against current status of the species to determine if implementation of the proposed action is likely to reduce appreciably the likelihood of both the survival and recovery of the species in the wild.

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STATUS OF THE SPECIES

Listing History

The Service listed the Mojave population of desert tortoise (all desert tortoises north and west of the Colorado River in Arizona, Utah, Nevada, and California) as threatened on April 2, 1990 [55 Federal Register (FR) 12178].

Recovery Plan

The Service (1994, 2011) issued initial recovery and revised recovery plans for the desert tortoise. The 1994 recovery plan recommended that a scientifically credible monitoring plan be developed to determine that the population exhibited a statistically significant upward trend or remained stationary for at least 25 years and that enough habitat would be protected within a recovery unit or the habitat and populations be managed intensively enough to ensure long-term viability. Because both minimum population densities and minimum population numbers need to be considered to ensure recovery, the Service further recommended that reserves be at least 1,000 square miles. Smaller reserves that provide high-quality, secure habitat for 10,000 to 20,000 adult desert tortoises should provide comfortable persistence probabilities for the species well into the future when populations are well above minimum viable density (e.g., 30 or more

1994, page C54). Conversely, populations with densities below approximately 10 adults per square mile are in danger of extinction (Service 1994, page 32).

“Adult” desert tortoise connotes reproductive maturity. Desert tortoises may become reproductive at various sizes. We have used the term “adult” in this biological opinion to indicate reproductive status. In range-wide sampling and for pre-project surveys, the Service uses 180 millimeters as its cut-off length for counting desert tortoises, because the Styrofoam models used for training are 180 millimeters in length and surveyors fail to detect desert tortoises smaller than 180 millimeters at higher rates. To conform to this standard, we refer those animals that are 180 millimeters and larger as “large” desert tortoises; we refer to individuals smaller than 180 millimeters as “small” desert tortoises.

We consider the “mean carapace length” to be the most appropriate measurement for the size of a desert tortoise. This length is the straight-line distance along the middle of the shell from the front edge of the top shell of the desert tortoise (the carapace) to the rear edge.

In the revised recovery plan for the desert tortoise, the Service (2011) identified the need for “conservation areas” to protect existing desert tortoise populations and habitat. These areas include designated critical habitat, areas of critical environmental concern, the Desert National Wildlife Refuge, National Park Service lands, and other conservation areas or easements managed for desert tortoises. The revised recovery plan lists three objectives and associated criteria to achieve delisting. The first objective is to maintain self-sustaining populations of desert tortoises within each recovery unit into the future; the criterion is that the rates of

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single generation), as measured by extensive, range-wide monitoring across conservation areas within each recovery unit and by direct monitoring and estimation of vital rates (recruitment, survival) from demographic study areas within each recovery unit.

The second objective addresses the distribution of desert tortoises. The goal is to maintain well- distributed populations of desert tortoises throughout each recovery unit; the criterion is that the distribution of desert tortoises throughout each conservation area increase over at least 25 years.

The final objective is to ensure that habitat within each recovery unit is protected and managed to support long-term viability of desert tortoise populations. The criterion is that the quantity of desert tortoise habitat within each conservation area be maintained with no net loss until population viability is ensured.

The revised recovery plan (Service 2011) also recommends connecting blocks of desert tortoise habitat, such as critical habitat units and other important areas, to maintain gene flow between populations. Linkages defined using least-cost path analysis (Averill-Murray et al. 2013) illustrate a minimum connection of habitat for desert tortoises between blocks of habitat and represent priority areas for conservation of population connectivity. Figure 1 illustrates that, across the range, desert tortoises in areas under the highest level of conservation and management remain subject to numerous threats, stresses, and mortality sources.

Figure 1. Recovery units, critical habitat units, conservation areas, and contiguous high value

Threats

The threats described in the listing rule and both recovery plans (Service 1994, 2011) continue to

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affect the species. The most apparent threats to the desert tortoise are those that result in mortality and permanent habitat loss across large areas, such as urbanization and large-scale renewable energy projects and those that fragment and degrade habitats, such as proliferation of roads and highways, off-highway vehicle activity, wildfire, and habitat invasion by non-native invasive plant species.

We remain unable to quantify how threats affect desert tortoise populations. The assessment of the original recovery plan emphasized the need for a better understanding of the implications of multiple, simultaneous threats facing desert tortoise populations and of the relative contribution of multiple threats on demographic factors (i.e., birth rate, survivorship, fecundity, and death rate; Tracy et al. 2004).

To better understand the relationship of threats to populations of desert tortoises and the most effective manner to implement recovery actions, the Service’s Desert Tortoise Recovery Office developed a spatial decision support system that models the interrelationships of threats to desert tortoises and how those threats affect population change. The spatial decision support system describes the numerous threats that desert tortoises face, explains how these threats interact to affect individual animals and habitat, and how these effects in turn bring about changes in populations. For example, we have long known that the construction of a transmission line can result in the death of desert tortoises and loss of habitat. We have also known that common ravens, known predators of desert tortoises, use transmission line pylons for nesting, roosting, and perching and that the access routes associated with transmission lines provide a vector for the introduction and spread of invasive weeds and facilitate increased human access into an area. Increased human access can accelerate illegal collection and release of desert tortoises and their deliberate maiming and killing, as well as facilitate the spread of other threats associated with human presence, such as vehicle use, garbage and dumping, and invasive plants (Service 2011a). Changes in the abundance of native plants, because of invasive weeds, can compromise the physiological health of desert tortoises, making them more vulnerable to drought, disease, and predation. The spatial decision support system allows us to map threats across the range of the desert tortoise and model the intensity of stresses that these multiple and combined threats place on desert tortoise populations.

The following map Figure 2 depicts the 12 critical habitat units of the desert tortoise, linkages between conservation areas for the desert tortoise and the aggregate stress that multiple, synergistic threats place on desert tortoise populations, as modeled by the spatial decision support system. Conservation areas include designated critical habitat and other lands managed for the long-term conservation of the desert tortoise (e.g., the Desert Tortoise Natural Area, Joshua Tree National Park, and the Desert National Wildlife Refuge).

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Figure 2. Critical habitat units, recovery units, and linkages

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Five-Year Review

Section 4(c)(2) of the Endangered Species Act requires the Service to conduct a status review of each listed species once every 5 years. The purpose of a 5-year review is to evaluate whether the species’ status has changed since listing (or since the most recent 5-year review); these reviews, at the time of their completion, provide the most up-to-date information on the range-wide status of the species. For this reason, we are appending the 5-year review of the status of the desert tortoise (Appendix A; Service 2010) to this biological opinion and are incorporating it by reference to provide most of the information needed for this section of the biological opinion. The following paragraphs provide a summary of the relevant information in the 5-year review.

In the 5-year review, the Service discusses the status of the desert tortoise as a single distinct population segment and provides information on the Federal Register notices that resulted in its listing and the designation of critical habitat. The Service also describes the desert tortoise’s ecology, life history, spatial distribution, abundance, habitats, and the threats that led to its listing (i.e., the five-factor analysis required by section 4(a)(1) of the Endangered Species Act). In the 5-year review, the Service concluded by recommending that the status of the desert tortoise as a threatened species be maintained.

With regard to the status of the desert tortoise as a distinct population segment, the Service concluded in the 5-year review that the recovery units recognized in the original and revised recovery plans (Service 1994 and 2011, respectively) do not qualify as distinct population segments under the Service’s distinct population segment policy (61 FR 4722; February 7, 1996). We reached this conclusion because individuals of the listed taxon occupy habitat that is relatively continuously distributed, exhibit genetic differentiation that is consistent with isolation-by-distance in a continuous-distribution model of gene flow, and likely vary in behavioral and physiological characteristics across the area they occupy as a result of the transitional nature of, or environmental gradations between, the described subdivisions of the Mojave and Colorado deserts.

The Service summarizes information in the 5-year review with regard to the desert tortoise’s ecology and life history. Of key importance to assessing threats to the species and to developing and implementing a strategy for recovery is that desert tortoises are long lived, require up to 20 years to reach sexual maturity, and have low reproductive rates during a long period of reproductive potential. The number of eggs that a female desert tortoise can produce in a season is dependent on a variety of factors including environment, habitat, availability of forage and drinking water, and physiological condition. Predation seems to play an important role in clutch failure. Predation and environmental factors also affect the survival of hatchlings. The Service notes in the 5-year review that the combination of the desert tortoise’s late breeding age and a low reproductive rate challenges our ability to recover the species.

The 5-year review also notes that desert tortoises increase their reproduction in high rainfall years; more rain provides desert tortoises with more high quality food (i.e., plants that are higher in water and protein), which, in turn, allows them to lay more eggs. Conversely, the physiological stress associated with foraging on food plants with insufficient water and nitrogen

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may leave desert tortoises vulnerable to disease, and the reproductive rate of diseased desert tortoises is likely lower than that of healthy animals. Young desert tortoises also rely upon high-quality, low-fiber plants (e.g., native annual plants) with nutrient levels not found in the invasive weeds that have increased in abundance across its range (Oftedal et al. 2002; Tracy et al. 2004). Compromised nutrition of young desert tortoises likely represents an effective reduction in reproduction by reducing the number of animals that reaches adulthood. Consequently, although we do not have quantitative data that show a direct relationship, the abundance of weedy species within the range of the desert tortoise has the potential to affect the reproduction of desert tortoises and recruitment into the adult population in a negative manner.

The vast majority of threats to the desert tortoise or its habitat are associated with human land uses. Using captive neonate and yearling desert tortoises, Drake et al. (2016) found that individuals “eating native forbs had better body condition and immune functions, grew more,

consuming any other diet”; health and body condition declined in individuals fed only grasses (native or non-native). Current information indicates that invasive species likely affect a large portion of the desert tortoise’s range. Furthermore, high densities of weedy species increase the likelihood of wildfires; wildfires, in turn, destroy native species and further the spread of invasive weeds.

Drake et al. (2015) compared movement patterns, home-range size, behavior, microhabitat use, reproduction, and survival for adult desert tortoises located in, and adjacent to, burned habitat in Nevada. They noted that the fires killed many desert tortoises but found that, in the first five years post-fire, individuals moved deeper into burned habitat on a seasonal basis and foraged more frequently in burned areas (corresponding with greater production of annual plants and herbaceous perennials in these areas). Production of annual plants upon which desert tortoises feed was 10 times greater in burned versus unburned areas but was dominated by non-native species (e.g., red brome [Bromus rubens]) that frequently have lower digestibility than native vegetation. During years six and seven, the movements of desert tortoises into burned areas contracted with a decline in the live cover of a perennial forage plant that rapidly colonizes burned areas. Drake et al. (2015) did not find any differences in health or survivorship for desert tortoises occupying either habitat (burned or unburned) during this study or in reproduction during the seventh year after the fire.

Since the completion of the 5-year review, the Service has issued several biological opinions that affect large areas of desert tortoise habitat because of numerous proposals to develop renewable energy within its range. These biological opinions concluded that proposed solar plants were not likely to jeopardize the continued existence of the desert tortoise primarily because they were located outside of critical habitat and areas of critical environmental concern designated by the Bureau that contain most of the land base required for the recovery of the species. The proposed actions also included numerous measures intended to protect desert tortoise during the construction of the projects, such as translocation of affected individuals. In aggregate, these projects would result in an overall loss of approximately 48,041 acres of habitat of the desert tortoise. We also predicted that the project areas supported up to 4,363 desert tortoises; we concluded that most of these individuals were small desert tortoises, that most adults would

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likely be translocated from project sites, and that most mortalities would b6e small desert tortoises (< 180 millimeters) that were not detected during clearance surveys. To date, 660 desert tortoises have been observed during construction of solar projects (see Appendix B); most of these individuals were translocated from work areas, although some desert tortoises have been killed. The mitigation required by the Bureau and California Energy Commission (the agencies permitting some of these facilities) resulted in the acquisition of private land and funding for the implementation of various actions that are intended to promote the recovery of the desert tortoise. These mitigation measures are consistent with recommendations in the recovery plans for the desert tortoise; many of the measures have been derived directly from the recovery plans and the Service supports their implementation. We expect that, based on the best available scientific information, they will result in conservation benefits to the desert tortoise; however, it is difficult to assess how desert tortoise populations will respond because of the long generation time of the species. Appendix B summarizes information regarding the solar projects that have undergone formal consultation with regard to the desert tortoise.

In August 2016, the Service (2016) issued a biological opinion to the Bureau for a land use plan amendment under the Desert Renewable Energy Conservation Plan. The land use plan amendment addressed all aspects of the Bureau’s management of the California Desert Conservation Area; however, the Service and Bureau agreed that only those aspects related to the construction, operation, maintenance, and decommissioning of renewable energy facilities were likely to adversely affect the desert tortoise. The land use plan amendment resulted in the designation of approximately 388,000 acres of development focus areas where the Bureau would apply a streamlined review process to applications for projects that generate renewable energy; the Bureau estimated that approximately 11,290 acres of modeled desert tortoise habitat within the development focus areas would eventually be developed for renewable energy. The Bureau also adopted numerous conservation and management actions as part of the land use plan amendment to further reduce the adverse effects of renewable energy development on the desert tortoise.

The land use plan amendment also increased the amount of land that the Bureau manages for conservation in California (e.g., areas of critical environmental concern, California Desert National Conservation Lands, etc.) from 6,118,135 to 8,689,669 acres (Bureau 2015); not all of the areas subject to increased protection are within desert tortoise habitat. The Bureau will also manage lands outside of development focus areas according to numerous conservation and management actions; these conservation and management actions are more protective of desert tortoises than direction contained in the previous land use plan. The Service (2016) concluded that the land use plan amendment was not likely to jeopardize the continued existence of the desert tortoise and would benefit its recovery.

In addition to the biological opinions issued for solar development within the range of the desert tortoise, the Service (2012) also issued a biological opinion to the Department of the Army (Army) for the use of additional training lands at Fort Irwin. As part of this proposed action, the Army translocated approximately 650 adult desert tortoises from 18,197 acres of the southern area of Fort Irwin, which had been off-limits to training, to lands south of the base that are

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managed by the Bureau and the Army. The Army would also use an additional 48,629 acres that lie east of the former boundaries of Fort Irwin; much of this parcel is either too mountainous or too rocky and low in elevation to support numerous desert tortoises. As part of the proposed action, the Army also acquired approximately 100,000 acres of non-federal land within the Superior-Cronese Critical Habitat Unit for management for conservation of desert tortoises. It also purchased the base property of three cattle allotments; the Bureau subsequently re-allotted the forage on those allotments to wildlife. The Army also funded several other activities aimed at conserving desert tortoises in the current planning area.

The Service also issued a biological opinion to the Department of the Navy (Navy) that considered the effects of the expansion of the Marine Corps Air Ground Combat Center at Twentynine Palms (Service 2017). We concluded that the Navy’s proposed action, the use of approximately 167,982 acres of public and private land for training, was not likely to jeopardize the continued existence of the desert tortoise. Most of the expansion area lies within the Johnson Valley Off-highway Vehicle Recreation Area. As part of this proposed action, the Navy translocated 997 adult desert tortoises from the expansion area to 4 recipient sites to the north and east of the expansion area (Henen 2019). The Lucerne-Ord and Siberia sites are entirely within Bureau-managed lands, and the Rodman-Sunshine Peak North and Cleghorn sites overlap Bureau-managed lands and lands managed by the Navy. The Lucerne-Ord site lies within the Ord-Rodman Area of Critical Environmental Concern. The Navy translocated desert tortoises from the Johnson Valley Off-highway Vehicle Recreation Area into populations that were below the Service’s established minimum viable density, to attempt to augment these populations and make them more viable in the long-term.

The Service also issued a biological opinion to the Navy that considered the effects of the expansion of the Naval Air Weapons Station at China Lake (Service 2019). We concluded that the Navy’s proposed action, the use of approximately 2,777 acres of the 26,509-acre Cuddeback Range expansion area, was not likely to jeopardize the continued existence of the desert tortoise. The Cuddeback Range lies within the Superior-Cronese Critical Habitat Unit. However, all of the disturbance would occur in a previously disturbed area that the U.S. Air Force historically used as a target zone. The Navy will include the entire Cuddeback Range in its Integrated Natural Resource Management Plan and construct a perimeter fence around the range to prevent trespass by the public. These actions will provide conservation benefits for plants, fish, and wildlife within the area, including the desert tortoise. Because the Navy will not disturb most of the area, it did not translocate any desert tortoises as part of this action.

The incremental effect of the larger actions (i.e., solar development, the expansions of Fort Irwin and the Marine Corps Air Ground Combat Center) on the desert tortoise is unlikely to be positive, despite the numerous conservation measures that have been (or will be) implemented as part of the actions. The acquisition of private lands as mitigation for most of these actions increases the level of protection afforded these lands; however, these acquisitions do not create new habitat and Federal, State, and privately managed lands remain subject to most of the threats and stresses we discussed previously in this section. Although land managers have been implementing measures to manage these threats and we expect, based on the best available

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scientific information, that such measures provide conservation benefits to the desert tortoise, we have been unable, to date, to determine whether the expected benefits of the measures have been realized, at least in part because of the low reproductive capacity of the desert tortoise. Therefore, the conversion of habitat into areas that are unsuitable for this species continues the trend of constricting the desert tortoise into a smaller portion of its range.

As the Service notes in the 5-year review (Service 2010), “(t)he threats identified in the original listing rule continue to affect the (desert tortoise) today, with invasive species, wildfire, and renewable energy development coming to the forefront as important factors in habitat loss and conversion. The vast majority of threats to the desert tortoise or its habitat are associated with human land uses.”

Climate change is likely to affect the prospects for the long-term conservation of the desert tortoise. For example, predictions for climate change within the range of the desert tortoise suggest more frequent and/or prolonged droughts with an increase of the annual mean temperature by 3.5 to 4.0 degrees Celsius. The greatest increases will likely occur in summer (June-July-August mean increase of as much as 5 degrees Celsius [Christensen et al. 2007]). Precipitation will likely decrease by 5 to 15 percent annually in the region; with winter precipitation decreasing by up to 20 percent and summer precipitation increasing by up to 5 percent. Because germination of the desert tortoise’s food plants is highly dependent on cool-season rains, the forage base could be reduced due to increasing temperatures and decreasing precipitation in winter. Although drought occurs routinely in the Mojave Desert, extended periods of drought have the potential to affect desert tortoises and their habitats through physiological effects to individuals (i.e., stress) and limited forage availability. To place the consequences of long-term drought in perspective, Longshore et al. (2003) demonstrated that even short-term drought could result in elevated levels of mortality of desert tortoises. Therefore, long-term drought is likely to have even greater effects, particularly given that the current fragmented nature of desert tortoise habitat (e.g., urban and agricultural development, highways, freeways, military training areas, etc.) will make recolonization of extirpated areas difficult, if not impossible.

Core Criteria for the Jeopardy Determination

When determining whether a proposed action is likely to jeopardize the continued existence of a species, we are required to consider whether the action would “reasonably be expected, directly or indirectly, to reduce appreciably the likelihood of both the survival and recovery of a listed species in the wild by reducing the reproduction, numbers, or distribution of that species” (50 CFR 402.02). Although the Service does not explicitly address these metrics in the 5-year review, we have used the information in that document and more recent information to summarize the status of the desert tortoise with respect to its reproduction, numbers, and distribution.

Reproduction

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In the 5-year review, the Service notes that desert tortoises increase their reproduction in high rainfall years; more rain provides desert tortoises with more high quality food (i.e., plants that are higher in water and protein), which, in turn, allows them to lay more eggs. Conversely, the physiological stress associated with foraging on food plants with insufficient water and nitrogen may leave desert tortoises vulnerable to disease (Oftedal 2002 in Service 2010), and the reproductive rate of diseased desert tortoises is likely lower than that of healthy animals. Young desert tortoises also rely upon high-quality, low-fiber plants (e.g., native annual plants) with nutrient levels not found in the invasive weeds that have increased in abundance across its range (Oftedal et al. 2002; Tracy et al. 2004). Compromised nutrition of young desert tortoises likely represents an effective reduction in reproduction by reducing the number of animals that reaches adulthood; see previous information from Drake et al. (2015). Consequently, although we do not have quantitative data that show a direct relationship, the abundance of weedy species within the range of the desert tortoise has the potential to affect the reproduction of desert tortoises and recruitment into the adult population in a negative manner.

Various human activities have introduced numerous species of non-native invasive plants into the California desert. Routes that humans use to travel through the desert (paved and unpaved roads, railroads, motorcycle trails, etc.) serve as pathways for new species to enter habitat of the desert tortoise and for species that currently occur there to spread. Other disturbances of the desert substrate also provide invasive species with entry points into the desert. Figure 3 depicts the potential for these species to invade habitat of the desert tortoise. The abundance and distribution of invasive weeds may compromise, at least to some degree in localized areas across its range, the reproductive capacity of the desert tortoise by the; the continued increase in human access across the desert likely continues to facilitate the spread of weeds and further affect the reproductive capacity of the species.

Figure 3. Potential for exotic plant invasion in desert tortoise habitat.

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Numbers

In the 5-year review, the Service (2010) discusses various means by which researchers have attempted to determine the abundance of desert tortoises and the strengths and weaknesses of those methods. Due to differences in area covered and especially to the non-representative nature of earlier sample sites, data gathered by the Service’s current range-wide monitoring program cannot be reliably compared to information gathered through other means at this time.

Data from small-scale study plots (e.g., one square mile) established as early as 1976 and surveyed primarily through the mid-1990s indicate that localized population declines occurred at many sites across the desert tortoise’s range, especially in the western Mojave Desert. Spatial analyses of more widespread surveys also found evidence of relatively high mortality in some parts of the range (Tracy et al. 2004). Although population densities from the local study plots cannot be extrapolated to provide an estimate of the number of desert tortoises on a range-wide basis, historical densities in some parts of the desert exceeded 38 per square kilometer; (Tracy et al. 2004). The Service (2010) concluded that “appreciable declines at the local level in many areas, which coupled with other survey results, suggest that declines may have occurred more broadly.”

The range-wide monitoring that the Service initiated in 2001 is the first comprehensive attempt to determine the densities of desert tortoises in conservation areas across their range. Allison and McLuckie (2018) used annual density estimates obtained from this sampling effort to evaluate range-wide trends in the density of desert tortoises over time. (All references to the density of desert tortoises within each sampling stratum are averages. Some local areas within each sampling stratum support higher densities and some lower; desert tortoises do not occur in uniform densities across large areas.) This analysis indicates that densities in the Northeastern Mojave Recovery Unit have increased since 2004, with the increase apparently resulting from increased survival of adults and sub-adults moving into the adult size class. The analysis also indicates that the populations in the other four recovery units are declining; Table 1 depicts the estimated abundance of desert tortoises within the recovery units and the change in abundance. Surveys did not include the steepest slopes in these desert tortoise conservation areas; although the model developed by Nussear et al. (2009) generally rates steep slopes as less likely to support desert tortoises, we know from recent research that they occur in these areas.

Table 1: Change in desert tortoise abundance in recovery units (Allison and McLuckie 2018).

Recovery Units Modeled Habitat (km2)

2004 Abundance

2014 Abundance

Change in Abundance

Western Mojave 23,139 131,540 64,871 -66,668 Colorado Desert 18,024 103,675 66,097 -37,578 Northeastern Mojave 10,664 12,610 46,701 +34,091 Eastern Mojave 16,061 75,342 24,664 -50,679 Upper Virgin River 613 13,226 10,010 -3,216

Total: 68,501 336,393 212,343 -124,050

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To further examine the status of desert tortoise populations over time, we compared the densities of desert tortoises in the Western Mojave Recovery Unit between 2004 and 2014. Overall, the Service (2015) estimated that the number of desert tortoises declined from 126,346 in sampled areas in 2004 to 85,686 in 2014. Densities increased only in the Northeastern Mojave Recovery Unit, from 4,920 to 18,220. Historical survey data from numerous plots in the Western Mojave Recovery Unit during the late 1970s and early 1980s suggest that adult desert tortoise densities ranged from 19 to 58 per square kilometer (Tracy et al. 2004). That is, the work by Tracy et al. (2004) indicates that the density of desert tortoises has already declined by 2004.

Allison (2014) evaluated changes in size distribution of desert tortoises since 2001. In the Western Mojave and Colorado Desert recovery units, the relative number of juveniles to adults indicates that juvenile numbers are declining faster than adults. In the Eastern Mojave, the number of juvenile desert tortoises is also declining, but not as rapidly as the number of adults. In the Upper Virgin River Recovery Unit, trends in juvenile numbers are similar to those of adults; in the Northeastern Mojave Recovery Unit, the number of juveniles is increasing, but not as rapidly as are adult numbers in that recovery unit. Juvenile numbers, like adult densities, are responding in a directional way, with increasing, stable, or decreasing trends, depending on the recovery unit where they are found.

In this context, we consider “juvenile” desert tortoises to be animals smaller than 180 millimeters in length. The Service does not include juveniles detected during range-wide sampling in density estimations because they are more difficult to detect and surveyors frequently do not observe them during sampling. However, this systematic range-wide sampling provides us with an opportunity to compare the proportion of juveniles to adults observed between years.

Distribution

Prior to 1994, desert tortoises were extirpated from large areas within their distributional limits by urban and agricultural development (e.g., the cities of Barstow and Lancaster, California; Las Vegas, Nevada; and St. George, Utah; etc.; agricultural areas south of Edwards Air Force Base and east of Barstow), military training (e.g., Fort Irwin, Leach Lake Gunnery Range), and off-road vehicle use (e.g., portions of off-road recreation areas managed by the Bureau and unauthorized use in areas such as east of California City, California).

Urban development around Las Vegas has likely been the largest contributor to habitat loss throughout the range since 1994. Desert tortoises have essentially been removed from the 18,197-acre southern expansion area at Fort Irwin (Service 2012). The development of large solar facilities has also reduced the amount of habitat available to desert tortoises. No solar facilities have been developed within areas of critical environmental concern that the Bureau has designated for the desert tortoise in California, although such projects have occurred in areas that the Service considers important linkages between conservation areas (e.g., Silver State South Project in Nevada).

In recognition of the absence of specific and recent information on the location of habitable areas within the Mojave Desert, especially at the outer edges, Nussear et al. (2009) developed a

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quantitative, spatial habitat model for the desert tortoise north and west of the Colorado River Figure 4. The model incorporates environmental variables such as precipitation, geology, vegetation, and slope and is based on occurrence data of desert tortoises from sources spanning more than 80 years, including data from the 2001 to 2008 range-wide monitoring surveys. The model predicts the relative potential for desert tortoises to be present in any given location, given the combination of habitat variables at that location in relation to areas of known occupancy throughout the range. Calculations of the amount of desert tortoise habitat in the 5-year review (Service 2010) and in this biological opinion use of a threshold of 0.5 or greater predicted value for potential desert tortoise habitat. The model does not account for anthropogenic effects to habitat and represents the potential for occupancy by desert tortoises absent these effects.

Figure 4. Modeled habitat of the desert tortoise (Nussear et al. 2009).

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Table 2 depicts acreages of habitat (as modeled by Nussear et al. 2009, using only areas with a probability of occupancy by desert tortoises greater than 0.5 as potential habitat) within the recovery units of the desert tortoise and of impervious surfaces as of 2006 (Fry et al. 2011); calculations are by Darst (2014). Impervious surfaces include paved and developed areas and other disturbed areas that have zero probability of supporting desert tortoises. All units are in acres.

Table 2: Modeled habitat of the desert tortoise

Recovery Units Modeled Habitat Impervious Surfaces (percentage)

Remaining Modeled Habitat

Western Mojave 7,585,312 1,989,843 (26) 5,595,469 Colorado Desert 4,950,225 510,862 (10) 4,439,363 Northeastern Mojave 3,012,293 386,182 (13) 2,626,111 Eastern Mojave 4,763,123 825,274 (17) 3,937,849 Upper Virgin River 231,460 84,404 (36) 147,056

Total: 20,542,413 3,796,565 (18) 16,745,848

The Service (2010) concluded in its 5-year review that the distribution of the desert tortoise has not changed substantially since the publication of the original recovery plan in 1994 in terms of the overall extent of its range. Since 2010, we again conclude that the species’ distribution has not changed substantially in terms of the overall extent of its range, although desert tortoises have been removed from several thousand acres because of solar development, military activities, and other project development.

ENVIRONMENTAL BASELINE

The implementing regulations for section 7(a)(2) (50 CFR 402.02) define the environmental baseline as “the past and present impacts of all Federal, State, or private actions and other human activities in the action area, the anticipated impacts of all proposed Federal projects in the action area that have already undergone formal or early section 7 consultation, and the impact of State or private actions which are contemporaneous with the consultation in process.”

Action Area

The “action area” refers to “all areas to be affected directly or indirectly by the Federal action and not merely the immediate area involved in the action” (50 CFR 402.02). The Federal action we are considering in this biological opinion comprises the area of the proposed solar facility and its ancillary features, the translocation site, and the mitigation lands. The proposed solar facility and its ancillary features include the solar field, the generator tie-in and service lines, the laydown area, and the access road into the solar plant from Highway 395. AECOM (2019) estimated the action area to cover 764 acres. That acreage does not include the access road from Highway 395, which is appropriate because the proposed action will affect only the road surface there.

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The translocation site comprises up to 1,280 acres of lands managed by the Bureau within the Fremont-Kramer Area of Critical Environmental Concern. HDSI will evaluate the habitat characteristics of sections 6, 7, and 8 of Township 9 North, Range 5 West and section 12 of Township 9 North, Range 6 West. It will then select up to 1,280 acres of the lands that meet criteria for translocation (i.e., areas with appropriate shelters, such as burrows, caliche caves, washes, or substantial shrub cover, that are away from resident animals).

We do not know the site of the mitigation lands at this time. The mitigation parcel will be within either the Fremont-Kramer or Superior-Cronese areas of critical environmental concern.

Previous Section 7 Consultations within the Action Area

Project Site

The Service (1998) concluded that the transfer of all properties within the former George Air Force Base out of Federal ownership was not likely to jeopardize the continued existence of the desert tortoise. Since that consultation, the Economic Development Administration and Service have consulted several times on infrastructure improvements within the boundaries of the former George Air Force Base; in all of those consultations, the Economic Development Administration determined that its proposed action was not likely to adversely affect desert tortoises and the Service concurred.

Translocation Site

We are unaware of any biological opinions for activities within the translocation site. Because the Bureau manages the lands within the site, its activities within the site conform to the current land use plan. In the most recent consultation on its management direction, the Service (2016) concluded that the Bureau’s most recent land use plan amendment was not likely to jeopardy the continued existence of the desert tortoise or result in the destruction or adverse modification of its critical habitat. The translocation site is within the Bureau’s Fremont-Kramer Area of Critical Environmental Concern. The Bureau (2016) defines areas of critical environmental concern as areas “within public lands where special management attention is required to protect and prevent irreparable damage to important historic, cultural, or scenic values, fish and wildlife resources or other natural systems of processes, or to protect life and safety from natural hazards.”

Mitigation Lands

Because we do not know the location of these lands, we cannot determine whether we have conducted previous consultation for activities within their boundaries. However, because they will be within either the Fremont-Kramer or Superior-Cronese areas of critical environmental concern, Bureau lands with the same management direction we discussed in the previous paragraph would most likely border the mitigation lands.

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Status of the Desert Tortoise in the Action Area

Project Site

HDSI conducted surveys of the project area, including the routes of the power lines, in 2017 and 2018. The habitat conservation plan (AECOM 2019) describes the methodology of the surveys.

Biologists detected five desert tortoises during the surveys; they did not detect all five on the same survey. Biologists also detected desert tortoises while conducting other fieldwork. Consequently, biologists likely found some of the same desert tortoises on different occasions.

Two detections occurred in the southern half of the solar field. Biologists observed one desert tortoise adjacent to the route of the proposed service line; the remainder were adjacent to the proposed generator tie-in line. Figures 3-2, 3-2a, 3-2b, and 3-2c in the habitat conservation plan depict all of the sightings.

Surveys generally do not detect all desert tortoises in an area because they spend so much time underground. For this reason, ECORPS (Wasz 2019) estimated the number of desert tortoises in the 764-acre action area using the equation in the Service’s (2018b) survey protocol. (In this discussion of ECORP’s work, we are using “action area” as ECORP used it; i.e., it included the proposed action and some distance around the project area.) It also estimated the number of desert tortoises in the 547-acre solar field using both the protocol’s equation and the average density from the Service’s range-wide sampling in the adjacent Fremont-Kramer Area of Critical Environmental Concern.

For the purposes of the analysis in this biological opinion, we will use the estimate derived for the action area by using the Service’s (2018b) protocol. We selected this method of calculating the number of desert tortoises present because it included the entire action area and presents, in our professional judgment, a reasonable estimate considering the highly disturbed nature of the site and the ongoing ability of desert tortoises to enter the rights-of-way for the power lines during construction, operation, maintenance, and decommissioning. ECORP (Wasz 2019) provides a detailed explanation of the method of estimating the numbers of desert tortoises that may be present.

ECORP (Wasz 2019) estimated that 23 desert tortoises occur in the 764-acre action area. Based on the results of the surveys and the equation in the Service’s (2018b) protocol, ECORP estimated this area supports 3.7 desert tortoises with a mean carapace length of 180 millimeters or greater. ECORP then estimated that 19.3 desert tortoises are less than 180 millimeters in length. These numbers differ slightly from those in the habitat conservation plan; we recognized while writing this biological opinion that the numbers in the habitat conservation plan were incorrect.

We emphasize that this number is an estimate. Desert tortoises may enter and leave the rights-of-way of the power lines at any time during construction, operation, maintenance, and

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decommissioning. For some time after hatching, the numbers of desert tortoises in the action area would increase.

Translocation Site

HDSI has not surveyed the translocation site to determine the density of desert tortoises. The translocation site is adjacent to two disjunct sections of land that comprise the Cuddeback-Kramer Preserve. In 2017, surveys detected one “subadult” and two “adult” desert tortoises on one of the sections (ECORP 2019). Previous surveys on the other section revealed sign of desert tortoises (e.g., burrows and scat) but no live desert tortoises.

We expect that the translocation site supports a density of desert tortoises that is similar to that of the Fremont-Kramer Critical Habitat Unit as a whole. In 2017, the Service (2018c) estimated the density of large desert tortoises at 4.1 individuals per square kilometer.

Mitigation Lands

Because we do not know the location of these lands, we do not have specific information about the status of desert tortoises on them. We expect that it would be similar to densities in the Superior-Cronese (1.7 individuals per square kilometer) or Fremont-Kramer critical habitat unit, as determined by range-wide sampling (Service 2018c).

Habitat Characteristics

Project Site

AECOM (2019) describes the project site as suitable habitat for the desert tortoise; “historic homesteads, trash dumping, and unauthorized off-highway vehicle use” have degraded some areas. Mojave creosote bush scrub occupies approximately 562 acres of the project area; disturbed creosote bush scrub, desert saltbush scrub, disturbed rabbitbrush scrub, disturbed lands, and developed industrial areas are also present.

Translocation Site

HDSI has not characterized the habitat on the translocation site. However, we expect that it is similar to the habitat on the adjacent parcels of the Cuddeback-Kramer Preserve. The draft management for the Cuddeback-Kramer Preserve (Unknown 2015) describes the preserve as Mojavean creosote bush scrub with “generally flat” terrain.

Mitigation Lands

Because we do not know the location of these lands, we do not have any information regarding its habitat characteristics. However, to meet the Service’s standards for issuance of an incidental take permit, the mitigation lands must support suitable habitat for the desert tortoise. If any disturbance is present on the mitigation lands, the Service would require HDSI to remediate it.

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EFFECTS OF THE ACTION

The implementing regulations for section 7(a)(2) define effects of the action as “the direct and indirect effects of an action on the species or critical habitat, together with the effects of other activities that are interrelated or interdependent with that action, that will be added to the environmental baseline. … Indirect effects are those that are caused by the proposed action and are later in time, but still are reasonably certain to occur. Interrelated actions are those that are part of a larger action and depend on the larger action for their justification. Interdependent actions are those that have no independent utility apart from the action under consideration” (50 CFR 402.02).

We conducted the analysis in the following sections based on the current conditions in the action area as we described in the Environmental Baseline section of this biological opinion. Several aspects of the proposed action may affect desert tortoises within the action area. These aspects are translocating desert tortoises from the project site, the installation of the fence to exclude desert tortoises from the solar site, killing or injuring of individuals and crushing of their burrows and eggs during construction, loss of habitat, and other miscellaneous effects.

In this section of the biological opinion, we will analyze how these various aspects of the proposed action affect desert tortoises and their habitat in a qualitative manner. In the Conclusions section of this biological opinion, we will integrate this general analysis with the best available information with regard to the numbers of desert tortoises and amount of habitat in the action area and recovery unit to determine whether the proposed action is likely to jeopardize the continued existence of the desert tortoise.

Effects Associated with Translocating Desert Tortoises from the Project Site

HDSI will translocate desert tortoises from the project area to the translocation site in accordance with the Service’s (2018a) translocation guidance and under specific direction for the proposed action from the Service and Department. During the preparation of the habitat conservation plan, the Service and Department encouraged HDSI to translocate desert tortoises found along the power lines to the translocation site. We recommended this course of action because of the degraded nature of the project site and the ongoing effects of operations and maintenance of the power lines and other effects of human access to that area. Also, such translocation will augment the population in the Fremont-Kramer Critical Habitat Unit. Augmentation of depleted populations is a recovery action in the recovery plan for the desert tortoise (Service 2011).

The first step in moving a desert tortoise from a project site, via translocation or moving the individual from harm’s way, involves their capture. In some cases, the authorized biologist may find the animals above ground or near the mouths of their burrows. In such cases, the authorized biologist can easily pick up the desert tortoise and transfer it to a container for transport or move the individuals out of harm’s way to immediately adjacent habitat. If desert tortoises are deeper in their burrows, the authorized biologist would excavate the burrows; we expect that excavating desert tortoises from deep in their burrows is likely more stressful for them than being captured on the surface of the ground.

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The capture and handling of desert tortoises can subject them to stress; stressed desert tortoises occasionally void their bladders. Desert tortoises store water in their bladders; this water is important to desert tortoises, particularly during times of low rainfall, in maintaining their life functions. Averill-Murray (2002) demonstrated that desert tortoises that urinated during handling had lower survival rates than those that did not. Consequently, desert tortoises that void their bladders are at an increased risk of dying after their translocation.

We acknowledge that, in every phase of implementation of the proposed activity, including during translocation, desert tortoises are at risk of being killed or injured when workers (including authorized biologists and biological monitors) drive outside of areas that have been fenced and cleared of desert tortoises. Small desert tortoises are at greater risk than larger animals because they are more difficult to see. This will generally be the case for every activity, and we will not repeat this throughout the biological opinion. We are aware of authorized biologist who have crushed desert tortoises with their vehicles while working on translocations; both resident and translocated animals are vulnerable.

The loss of small desert tortoises is not as deleterious to the population as the loss of reproductive animals, because they require up to 20 years to reach sexual maturity, have low reproductive rates during a long period of reproductive potential, and individuals experience relatively high mortality early in life (Service 2011).

Boarman (2002), in a review of literature on threats to the desert tortoise, stated that the adverse effects of translocation include increased risk of mortality, spread of disease, and reduced reproductive success. The tendency for translocated desert tortoises to spend more time above ground, moving through their environment, than animals within their home ranges exacerbates at least some of these threats. Recent research, using comparisons among resident desert tortoises (animals within their home ranges with translocated individuals nearby) and control desert tortoises (animals within their home ranges with no translocated individuals nearby), has provided substantial information on this issue. We will evaluate the potential effects of translocation on desert tortoises in the following paragraphs.

Field et al. (2007), Nussear (2004), and Nussear et al. (2012) have found that translocated animals seem to reduce movement distances following their first post-translocation hibernation to a level that is not significantly different from resident populations. As time increases from the date of translocation, most desert tortoises change their movement patterns from dispersed, random patterns to more constrained patterns, which indicate an adoption of a new home range (Nussear 2004).

In general, desert tortoises moved shorter distances (especially within their home ranges) exhibit more limited movement patterns after translocation. Desert tortoises that spend less time above ground are less vulnerable to predation and environmental extremes. Regardless of the distance desert tortoises would be moved, we expect that translocated animals would spend more time moving, at least during the first year, which means they would be more vulnerable to predators, adverse interactions with other desert tortoises, and weather conditions than resident animals. For example, in spring 2013, biologists translocated 108 large and 49 small desert tortoises from

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approximately 2,000 acres of the KRoad Moapa Solar Project on the Moapa River Indian Reservation northeast of Las Vegas; they also monitored 18 large desert tortoises as controls or residents. Extremely high temperatures during the summer may have killed two or more large translocated desert tortoises. Predators likely killed eight small translocated desert tortoises. No resident or control desert tortoises died during monitoring (Burroughs 2013).

Depending on the specific goal of translocating desert tortoises, translocating animals either short or long distances is likely to have differing effects. Hinderle et al. (2015) found that desert tortoises translocated less than 2 kilometers are likely to attempt to return to the point of capture. If those returning animals cannot regain access to the habitat from which they were removed, they are likely to wander more extensively or pace fence lines; both of these activities increase the likelihood that the desert tortoises may be attacked by predators or die from exposure to extreme temperatures. Therefore, when desert tortoises will not be able to regain access to their point of capture, translocating them to suitable habitat more than 2 kilometers away is likely to prevent them from returning. In this case, HDSI will move all desert tortoises more than 2 kilometers from the project site.

As we previously discussed, we expect that translocated desert tortoises would spend more time moving around. Because translocated desert tortoises spend more time moving, individuals that are moved during the summer months outside of their active season (i.e., from June to August) could be overexposed to heat and die from hyperthermia. HDSI will release desert tortoises only during the appropriate times of the year; therefore, desert tortoises will not be at risk of this threat.

As with other translocations (Nussear 2004; Field et al. 2007), we anticipate that predation is likely to be the primary source of post-translocation mortality. The level of winter rainfall may dictate the amount of predation observed in desert tortoises (Drake et al. 2010; Esque et al. 2010). Drake et al. (2010) documented a statistically significant relationship between decreased precipitation and increased predation of translocated desert tortoises at Fort Irwin. We are aware of two instances where monitoring of large numbers of control and resident desert tortoises accompanied the translocation of desert tortoises (Fort Irwin and Ivanpah Solar Electric Generating System). At Fort Irwin, Esque et al. (2010) found that “translocation did not affect the probability of predation: translocated, resident, and control tortoises all had similar levels of predation.” At the Ivanpah Solar Electric Generating System, Scherer et al. (2016) “found no

translocated, resident, and control desert tortoises in each size class. Predation by canids is the greatest source of mortality among translocated, resident, and control animals at several projects.

Drought conditions seem to affect translocated and resident desert tortoises similarly. Field et al. (2007) noted that studies from various sites “suggest that all (desert) tortoises at the (Large-scale Translocation Site) site, regardless of translocated or resident status, likely were negatively impacted by drought conditions at the site in 1997.” Field et al. (2007) noted that most of the translocated desert tortoises “quickly became adept at life in the wild,” despite the harsh

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conditions. Consequently, we have concluded that the amount of rainfall preceding translocation is not likely to decrease the survival rate of translocated desert tortoises.

Nussear et al. (2012) investigated the effects of translocation on reproduction in 120 desert tortoises. They found that, in the first year since translocation, the mean reproductive effort for translocated desert tortoises was slightly less than that of residents. Nussear et al. (2012) noted that the translocated animals may have benefited from being fed while in the pre-translocation holding facility; the food provided in the facility may have increased their production of eggs in the first year after translocation. In the second and third years after translocation, the mean number of eggs was not different between resident and translocated desert tortoises. (That is, absent the food the desert tortoises received in the holding facility, the first year’s reproduction may have been lower; the lack of difference in egg production between resident and translocated animals in subsequent years indicates that translocation did not have a long-term effect on reproductive output.)

Walde and Boarman (2013) reported on a microsatellite analysis of 72 hatchlings found in the area to which desert tortoises had been translocated from Fort Irwin. They found that, 4 years after translocation, most (if not all) of the hatchlings had been fathered by resident male desert tortoises, even though translocated males were well represented in the population. We do not know the reason for this difference; additional research into this situation is warranted. We do not view this lack of representation of the translocated males as being appreciably negative, at least in the short term, because minimal differentiation among subpopulations of desert tortoises occurs even at low levels of gene flow such as less than one migrant per year or even one migrant every few decades (see Latch et al. 2011). We expect that translocated males will ultimately begin siring offspring within the population during their lifespan.

Translocating desert tortoises may also adversely affect resident desert tortoises within the recipient area due to local increases in density. Increased densities may result in increased incidence of aggressive interactions between individuals, increased competition for available resources, increased incidence of predation that may not have occurred in the absence of translocation, and increased spread of upper respiratory tract disease or other diseases. Because we expect the project site to support few desert tortoises, we do not expect any adverse effects related to increased density.

During the translocation work at Fort Irwin, researchers tested over 200 desert tortoises for differences in the levels of corticosterone, which is a hormone commonly associated with stress responses in reptiles; Drake et al. (2012) “did not observe a measurable physiological stress response [as measured by (corticosterone)] within the first two years after translocation.” The researchers found no difference in stress hormone levels among resident, control, and translocated desert tortoises. For these reasons, we conclude that the addition of translocated desert tortoises to the recipient area would not result in detrimental effects to translocated or resident animals.

The Service based its guidance for the upper limit of the number of desert tortoises translocated into an area on the density of large animals. The Service generally recommends that the number

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of small desert tortoises released into a translocation area not exceed the number of released large individuals. Healthy populations have a large number of desert tortoises smaller than 180 millimeters (Turner et al. 1987). Additionally, natural mortality rates of smaller desert tortoises are greater than those of larger tortoises and we expect that small desert tortoises use resources differently than do large ones (Wilson et al. 1999). Finally, we expect that juveniles (small animals) and adults (large animals) interact much less frequently than do adults. Due to differences in habitat use, caused by both physical and physiological differences in large and small desert tortoises, we expect overlapping of ranges while the small desert tortoises are growing and dispersing. For these reasons, we do not expect translocating small desert tortoises is likely to result in density-dependent adverse effects.

Upper respiratory tract disease and other pathogens spread by direct contact between desert tortoises. Consequently, increasing the density of desert tortoises in the recipient areas has the potential to exacerbate the spread of diseases because, presumably, animals that occur in higher densities would have more opportunity to contact one another. Several circumstances are likely to reduce the magnitude of the threat of disease prevalence being exacerbated by translocation.

First, HDSI has proposed to use experienced biologists and approved handling techniques that are unlikely to result in substantially elevated stress levels in translocated animals; animals are less likely to succumb to disease when they are not stressed. Second, desert tortoises on project sites are currently part of a continuous population with the resident populations of the adjacent recipient sites and are likely to share similar pathogens and immunities. Third, Drake et al. (2012) indicated that translocation does not seem to increase stress in desert tortoises. Fourth, density-dependent stress is unlikely to occur for the reasons discussed previously in this section. Finally, biologists trained by the Service (or other specialists) will perform health assessments using Service-approved protocols and will not translocate any desert tortoise showing severe clinical signs of disease.

Post-translocation monitoring poses some threat to desert tortoises because of the additional handling these animals will experience. However, the Service will ensure that HDSI uses only experienced biologists to conduct this work. Therefore, we do not expect that surveys or the use of transmitters will kill or injure desert tortoises.

Based on this information, we anticipate that post-translocation survival rates will not significantly differ from that of resident animals. We expect that translocated desert tortoises would be at greatest risk during the time they are spending more time above ground than resident animals. We cannot precisely predict the level of post-translocation mortality because regional factors that we cannot control or predict (e.g., drought, predation related to a decreased prey base during drought, etc.) would likely exert the strongest influence on the rate of mortality and affect translocated and resident desert tortoises similarly.

In the Description of the Proposed Action section of this biological opinion, we acknowledged that HDSI might translocate desert tortoises to alternative sites in the Western Mojave Recovery Unit. If HDSI chooses to use an alternative site, the Service will evaluate the specific circumstances at the time to determine if re-initiation of formal consultation would be

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appropriate. In general, we expect that the translocating desert tortoises to any of the sites would result in the same effects and we would not need to re-initiate formal consultation.

Effects Associated with Construction of the Project

HDSI will install desert tortoise exclusion and security fencing (collectively, perimeter fencing) around the solar facility and remove all desert tortoises that it can locate on the proposed project site prior to ground disturbance. During construction of the perimeter fencing and the gen-tie and service lines and during other ground-disturbing activities that are outside of the fenced solar facility (i.e., access road), HDSI will perform pre-activity clearance surveys and employ monitors to move desert tortoises out of harm’s way if they re-enter work areas. For these reasons, we anticipate that construction is likely to kill few, if any, large desert tortoises.

Some potential always exists that surveyors may miss desert tortoises during clearance surveys and construction monitoring. We cannot predict how many of these large desert tortoises that clearance surveys and construction monitoring would miss. However, because HDSI will use qualified biologists, authorized by the Service for clearance surveys, we anticipate the number is likely to be small. Weather conditions can also affect the number of animals detected during surveys; warm weather after average or above-average rainfall would lead to more activity in desert tortoises, which would facilitate their detection.

Construction of the perimeter fence enclosing the solar facility can adversely affect desert tortoises. Desert tortoises that have been fenced out of their home territories can make repeated efforts to return to their original location and follow fence lines for long periods. Desert tortoises would die when exposed to harsh conditions (i.e., cold or hot temperatures) while pacing fences. We expect that few, if any, desert tortoises will experience this adverse effect because HDSI will translocate all individuals it finds during construction. Additionally, based on the survey results, the area surrounding the project supports few desert tortoises.

The installation of fencing may also reduce the home range size of some individuals that inhabit areas immediately adjacent to the fence alignments or that overlap the project footprint. This reduction could result in future injury or mortality of these individuals as they expand their home range into adjacent areas where unknown threats may occur or where adverse social or competitive interactions may occur with neighboring desert tortoises. Few, if any, desert tortoises are likely to experience this effect for the same reasons we discussed in the previous paragraph.

The generator tie-in and service lines would have different effects on desert tortoises than construction of the solar field. Construction of these power lines would take place outside of perimeter fencing. Equipment used to construct the power lines could crush desert tortoises. During construction, HDSI would monitor work activities and translocate desert tortoises they find to the recipient site.

Uncovered trenches or holes can trap desert tortoises; entrapped desert tortoises can die of exposure or be killed by predators. HDSI has proposed several measures, including checking

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excavations and assigning monitors to the project sites, to protect desert tortoises during activities that would occur outside the permanent perimeter fence. With these measures and because the amount of surface disturbance that we expect from the construction of the power lines is small, we expect that few, if any, desert tortoises are likely to be injured or killed.

Vehicles associated with the project may kill or injure desert tortoises as they work or travel along the paved access road and unpaved roads along the power lines. We are unable to separate the potential effects of the use of the paved access road by project-associated vehicles from those of the general public. We expect that vehicles using the paved access road are likely to kill or injure few desert tortoises because of the low density of desert tortoises in the area; the long-term use of this road likely has contributed to the current low density of desert tortoises.

Outside the perimeter fence of the solar facility, HDSI will limit vehicle speed to 15 miles per hour. Traveling at 15 miles per hour will allow drivers to see larger desert tortoises. Overall, we expect that few desert tortoises are likely to be killed or injured by vehicles associated with the construction of the project because the work would occur over a relatively short time and HDSI will train workers to be aware of the potential for desert tortoises to be on these roads.

Desert tortoises often construct their nests at the entrance to their burrows (Ennen et al.2012). Because HDSI will excavate all desert tortoise burrows found within the construction footprint prior to the onset of ground disturbance, the authorized biologist may detect at least some of the nests and eggs. Overall, we anticipate that detection of eggs is unlikely because the buried nests are difficult to find. Because hatchlings can take shelter in burrows of all sizes and are difficult to see due to their cryptic nature and their small size, surveyors are less likely to detect them than they are larger desert tortoises. Consequently, we expect that most of the hatchling and eggs are likely to remain in the work areas during construction. These desert tortoises will likely be killed during construction; however, given the low density of desert tortoises in the project area, we expect few nests or hatchlings to be present. Because construction activities would occur year round, we cannot predict whether these activities would affect hatchlings or eggs.

We cannot predict precisely how many desert tortoises may be injured or killed because of the numerous variables involved. For example, we do not know the precise number of desert tortoises onsite, the size of those individuals, whether eggs will be present at the time of construction, the time of year that construction occurs, and the weather before or during construction. Regardless of these factors, we expect that few large desert tortoises are likely to be killed or injured during construction because the project area does not support many large individuals; also, HDSI has proposed to implement measures that have proven effective in the past in reducing mortality and injury.

We acknowledge that more small desert tortoises may be present than large individuals; we also acknowledge that the smaller the desert tortoise, the more likely it is to be killed or injured during work activities because they are more difficult to detect. Several factors involved in the reproductive strategy of desert tortoises render the loss of small individuals less damaging to the population than the loss of large animals. As the recovery plan (1994) indicates, females do not reproduce until they are between 12 and 25 years old, they reproduce for the remainder of their

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long lives once they have reached reproductive age, and they may have 2 clutches of eggs per year. Under normal circumstances, large desert tortoises (i.e., reproductive individuals) have a low mortality rate. Conversely, the survival rate of juveniles is very low and probably varies from year to year. For these reasons, the loss of small desert tortoises and eggs because of the proposed action is not likely to affect the overall status of the desert tortoise, either locally or on a broader scale. Additionally, given the relatively few large desert tortoises in the project area, we expect that few small animals and eggs will be present.

Effects of Habitat Loss and Degradation

The following analysis provides an assessment of the effects that the habitat loss and degradation associated with the proposed project would have on desert tortoises within and around the project area. Construction of the solar facility would result in the loss of approximately 547 acres of desert tortoise habitat (AECOM 2019, page 2-2); some of the area within the proposed solar field is heavily disturbed and not suitable for desert tortoises. Construction of the power lines would occur in a 35-acre corridor; most of the disturbance in this area would be for pull and splice sites and would be temporary. HDSI would also use approximately 10 acres for access roads.

The area within the exclusion fence of the solar facility and the surrounding perimeter road would not be available to desert tortoises for foraging, breeding, or sheltering for the life of the project. Beyond the predicted life of the solar facility, the site could remain in some form of industrial use or be restored. Remaining in industrial use would extend the time that the habitat is no longer available to desert tortoises.

Following extensive disturbance and compaction, such as would likely occur during use of the solar facility, the time to recovery of the site to pre-project conditions would vary, depending on the nature and success of restoration efforts. In the absence of restoration, substrate that has been compacted in the Mojave Desert can require 50 to 300 years to achieve pre-disturbance condition (Lovich and Bainbridge 1999). Active restoration, including decompacting the substrate, seeding, and planting, can reduce the time required to restore desert ecosystems; the degree of success varies and depends on numerous variables, including the frequency of rainfall.

The presence of the solar facility would not impede the movement of desert tortoises in general. The Mojave River lies to the east of the site and Highway 395 to the west; desert tortoises are currently highly unlikely to cross either of these features. The Southern California Logistics Airport (i.e., the former George Air Force Base) lies to the south of the project site; the project would restrict movement to the south to a minor degree.

In summary, the project location is currently mostly isolated from adjacent desert tortoise habitat by natural and human-constructed features, except to the north. For this reason and because HDSI will translocate all desert tortoises it finds in the project area to the recipient site, the loss of habitat because of the project will have minimal, if any, effects on desert tortoises.

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Effects Associated with Operations and Maintenance

We are aware of occasions where desert tortoises have been able to enter fenced facilities, such as a pump station for a gas pipeline and an operating solar plant; they entered through gaps under the fencing or open gates. Flood events can damage fences to the point where desert tortoises may be able to enter the facilities. Once inside the fencing, desert tortoises would be at risk of being killed or injured by operations or maintenance activities. In general, we expect that operation and maintenance within the perimeter fence are likely to injure or kill few desert tortoises; however, if fences are poorly maintained, the degree of risk to desert tortoises would likely increase.

HDSI will inspect the exclusion fence monthly and immediately following all major rainfall events. HDSI will repair any damage to the fencing within 3 days of observing the damage and report to the Service to determine whether additional measures are necessary. Maintenance activities associated with repair of the exclusion fencing would likely kill or injure, few, if any, desert tortoises for the following reasons. First, fence repairs are likely to result in minimal ground disturbance in localized areas. Second, at least a portion of the work area would be on disturbed areas within the fenced project site. Third, the permanent perimeter roads, located outside the perimeter fencing, would allow access to most repair locations with minimal off-road travel. Fourth, HDSI will translocate any desert tortoises it finds during construction to the recipient site; we expect the surrounding areas also support few individuals. Finally, the applicant would ensure that repairs to the perimeter fence are performed under the direction of an authorized biologist, who will implement protective measures to reduce the potential for injury or mortality of desert tortoises.

Over the 35-year life of the project, HDSI will likely conduct ground-disturbing maintenance activities along the power lines. These activities have the potential to injure or kill desert tortoises primarily by vehicle strikes, as workers travel to and from work sites outside of fenced areas; the possibility exists that desert tortoises could be injured or killed by equipment or workers moving around a work site. HDSI proposes to implement protective measures during maintenance activities occurring outside the perimeter fence to reduce the potential effects. Also, we expect that, with the removal of desert tortoises during construction and the continuing isolation of habitat in this area, few desert tortoises are likely to inhabit the area along the power lines in the future. For these reasons, maintenance activities are likely to kill or injure few, if any, desert tortoises.

Effects Associated with Decommissioning the Project

Work associated with decommissioning the project is unlikely to result in injury to or mortality of desert tortoises for the following reasons. Desert tortoises would not be present within the fenced solar facility. Decommissioning activities along the power lines are unlikely to affect desert tortoises because we expect they will be absent from this area by the end date of the incidental take permit. We have reached this conclusion because HDSI has agreed to translocate all desert tortoises it finds during construction; additionally, future development not associated with the High Desert Solar Project and ongoing activities in the area are likely to result in the

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removal of remaining desert tortoises. In the even that a few individuals remain, the effects would be similar to those associated with construction and operation that we described in the previous section.

Effects Associated with Common Ravens

Indirect effects associated with construction, operation, maintenance, and decommissioning of the solar facility and the power lines may injure or kill desert tortoises. The project has the potential to attract common ravens and increase desert tortoise predation in the project area. Additionally, we are aware that common ravens frequent the adjacent composting and wastewater treatment facilities. We anticipate common ravens are likely to frequent the proposed project because they would offer perching, roosting, and possibly nesting sites; workers may also leave food unattended and various activities may kill other animals that common ravens would then scavenge. HDSI has proposed measures to address predation by common ravens associated with the project (ECORP 2019). In general, these measures include designing facilities to discourage common raven use, minimizing or eliminating food and water subsidies, reporting nesting common ravens to the Service, and providing training to on-site personnel.

We do not expect common ravens will have a measurable effect on desert tortoises in the project area because HDSI will translocate most, if not all, of the desert tortoises to the recipient site. However, common ravens will travel well beyond the project area in search of other subsidies and to nest. Therefore, common ravens that use the project facilities are likely to prey on desert tortoises well outside the project area.

Despite diligent implementation of these measures, common ravens are still likely to obtain some subsidies from the site. To address this effect, HDSI will participate in the regional management and monitoring program for common ravens. The Service developed this program in coordination with the Desert Managers Group, which is a consortium of land management agencies and some of the counties. Through the regional program, the Service monitors the number of common ravens in conservation areas, removes birds that are preying on desert tortoises, reduces the amount of breeding, and works with other partners to develop new means of reducing predation on desert tortoises.

We cannot reasonably predict the amount of predation of desert tortoises by common ravens that the proposed action is likely to add to current levels and we anticipate that measures proposed by HDSI are likely to eliminate some, but not all, common raven use of the project site. Implementation of the management program for common ravens, to which HDSI would contribute, is likely to reduce predation on desert tortoises throughout the western Mojave Desert. We expect that positive effects of the management of common ravens would occur within the Fremont-Kramer Area of Critical Environmental Concern.

Effects of Mitigation

In the habitat conservation plan, HDSI proposed to acquire approximately 568 acres of suitable desert tortoise habitat to offset the long-term effects of construction of the solar project. The

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mitigation lands will be located within the Western Mojave Recovery Unit, as defined in the revised recovery plan for the desert tortoise (Service 2011). To ensure that the acquisition will further recovery of the species, HDSI will acquire lands that are within an area of critical environmental concern as designated by the Bureau for the conservation of desert tortoises. (The boundaries of the Bureau’s areas of critical environmental concern include non-federal lands; acquisition of these lands is important for the recovery of the desert tortoise because of the subsequent management for conservation that will occur.) We do not know the specific locations of these lands at this time. HDSI will also provide for the long-term management for the mitigation lands.

Acquisition of the mitigation lands in and of itself meets one of the Service’s criteria for issuance of an incidental take permit (i.e., mitigate the effects of the incidental take to the maximum degree practicable). This acquisition allows for the conservation management of land that could otherwise be subject to uses that would kill desert tortoises and adversely affect their habitat. A crucial aspect of this acquisition is that it will occur within an area of critical environmental concern designated by the Bureau. (The boundaries of the Bureau’s areas of critical environmental concern include non-federal land. Because the Bureau does not manage these lands, activities that are detrimental to the recovery of desert tortoises can occur there.) The acquisition within an area of critical environmental concern ensures that the acquired lands are part of a large block of land where conservation management of desert tortoises is a high priority.

If the acquired lands require some form of restoration, HDSI or the conservation land manager will undertake that work. Because we do not know if the lands to be acquired will need restoration, we cannot assess the level of benefit that desert tortoises will accrue from restoration. However, the original and revised recovery plans (Service 1994, 2011) identify actions such as acquisition and restoration of disturbed lands as being necessary for the recovery of the desert tortoise. As noted in the Desorption of the Proposed Action section of this biological opinion, HDSI will use adaptive management to evaluate whether acquired lands require restoration. The Service will evaluate the specific circumstances at that time to determine if re-initiation of formal consultation would be appropriate. In general, we expect that the effects of restoration activities would be minor and need require re-initiation of formal consultation.

Implementation of some of the habitat restoration actions has the potential to result in adverse effects to the desert tortoise. For example, restoration workers driving to an acquired parcel could crush a desert tortoise on an unpaved road or injure or kill a desert tortoise while removing trash from the acquired lands. (Desert tortoises will occasionally hide in piles of trash.) Because HDSI will use qualified biologists authorized by the Service to either conduct or monitor the restoration work and because the amount of ground disturbance associated with the work is likely to be minor, we expect that few, if any, desert tortoises are likely to be killed or injured during activities on the acquired lands.

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CUMULATIVE EFFECTS

Cumulative effects include the “effects of future State or private activities, not involving Federal activities, that are reasonably certain to occur within the action area of the Federal action subject to consultation” (50 CFR 402.02). Future Federal actions that are unrelated to the proposed action are not considered in this section because they require separate consultation pursuant to section 7 of the Act. Because all future actions on lands managed by the Bureau (or Air Force, prior to their disposal) would require consultation, pursuant to section 7(a)(2) of the Endangered Species Act, we do not anticipate any cumulative effects associated with future activities on public lands. We are not aware of any actions that are reasonably certain to occur on non-federal lands within the action area.

CONCLUSION

As we stated previously in this biological opinion, “jeopardize the continued existence of” means to engage in an action that reasonably would be expected, directly or indirectly, to reduce appreciably the likelihood of both the survival and recovery of a listed species in the wild by reducing the reproduction, numbers, or distribution of that species (50 CFR 402.02). This regulatory definition focuses on how the proposed action would affect the reproduction, numbers, and distribution of the species under consideration in the biological opinion. For that reason, we have used those aspects of the desert tortoise’s status as the basis to assess the overall effect of the proposed action on the species.

Additionally, we determine whether a proposed action is likely “to jeopardize the continued existence of the species” through an analysis of how a proposed action affects the listed taxon within the action area in relation to the range of the entire listed taxon. For the desert tortoise, this process involves considering the effects at the level of the action area, then at the level of the recovery unit, and then finally for the range of the listed taxon. Logically, if a proposed action is unlikely to cause a measurable effect on the listed taxon within the action area, it is unlikely to affect the species throughout the recovery unit or the remainder of its range. Conversely, an action with appreciable effects on the listed entity in the action area may degrade the status of the species to the extent that it affects the recovery unit or the entire range.

In the following sections, we will synthesize the analyses contained in the Effects of the Action section of this biological opinion to determine how each of the proposed actions affects the reproduction, number, and distribution of the desert tortoise. We will then assess the effects of the proposed actions on the recovery of the species and whether they are likely to appreciably reduce the likelihood of both the survival and recovery of the desert tortoise in the wild.

Reproduction

The construction, operation, maintenance, and decommissioning of the High Desert Solar Project will not affect the reproductive capacity of desert tortoises.

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Numbers

ECORP (Wasz 2019) used the Service’s (2018b) recommended protocol to estimate that 23 desert tortoises occur in the 764-acre project area, of which 3.7 were large desert tortoises (i.e., mean carapace length of 180 millimeters or greater). We expect that fewer desert tortoises actually occur there because of the site’s disturbed condition; however, hatchlings could increase the total number for some time. We expect that HDSI will find and translocate most large desert tortoises from the project site. Some potential exists that HDSI will not detect every desert tortoise during clearance surveys; these individuals are likely to die during construction. We cannot predict how many, if any, that HDSI will miss. Because HDSI will use qualified individuals authorized by the Service and follow standard protocols when moving desert tortoises to the recipient site, desert tortoises are unlikely to die because of translocation.

We will round ECORP’s number to four large desert tortoises for this discussion and assume the worst-case scenario (i.e., that all four will die). To evaluate the effect of these mortalities on desert tortoises within the Western Mojave Recovery Unit, we assumed that the trend of decline of desert tortoises in the Western Mojave Recovery Unit continued until 2019 and used the data from the Service’s (2015) trend analysis to project the number of large individuals within the Western Mojave Recovery Unit. This extrapolation allows us to evaluate the loss of four desert tortoises compared to the current population estimate (2019). The results of this extrapolation are in Table 3.

Table 3. Extrapolated numbers of large desert tortoises in conservation areas of the Western Mojave Recovery Unit in 2014 and 2019.

Year Number of Large Desert Tortoises1

Lower 95 Percent Confidence Interval

Upper 95 Percent Confidence Interval

2014 17,645 11,155 27,912 2019 12,392 5,222 29,405

1 Allison (2019).

The numbers in the previous table do not include the number of large desert tortoises that reside outside of conservation areas. Therefore, we emphasize that the following calculation upon which we based this analysis is not precise; however, it allows for a reasonable approach to the analysis based on the best available information and our professional judgment.

The potential exists that HDSI’s activities related to translocation of desert tortoises at the recipient site and restoration at the mitigation site may kill or injure desert tortoises. We cannot reasonably determine how many individuals activities will affect because we do not know the precise location of those activities and desert tortoises are mobile. With the protective measures proposed by HDSI, we expect that few large desert tortoises are likely to be killed or injured. For the purposes of this analysis, we will add two large desert tortoises to the worst-case scenario for the project site.

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The loss of 6 desert tortoises at this time represents approximately 0.05 percent of the estimated number of large desert tortoises within conservation areas in Western Mojave Recovery Unit (6 / 12,392 x 100 = 0. 048).

The loss of six desert tortoises because of the proposed action is not likely to appreciably reduce the number of desert tortoises in the Western Mojave Recovery Unit. For this reason, we will not extend our analysis to the entire range of the listed taxon.

Recovery

We discussed the objectives and criteria to achieve recovery of the desert tortoise in the Status of the Desert Tortoise section of this biological opinion. The loss of habitat in the project area will not impede the recovery of the desert tortoise because the project is not located within a conservation area for desert tortoises. Additionally, the portion of the desert near the project is likely to experience more development in the future, which would further degrade habitat and displace or kill desert tortoises.

The translocation of desert tortoises from the project area to the recipient site is likely to provide a minor benefit to the recovery of desert tortoises. We have reached this conclusion because the desert tortoises in the project area are vulnerable to the unauthorized uses that currently occur on site. At the recipient site, these individuals will be less vulnerable to unauthorized uses and within a larger population of desert tortoises with which they can interact and breed. The number of desert tortoises in the Fremont-Kramer Area of Critical Environmental Concern has been in decline; for that reason, the Service plans to conduct population augmentation in that region in the future, as described in the recovery plan (Recovery Action 3, Augment depleted populations through a strategic program, Service 2011). The proposed action provides minor support for that effort.

The acquisition and long-term management of approximately 568 acres of private lands also implements a recovery goal for the desert tortoise (Recovery Action 2.9, secure lands/habitat for conservation, Service 2011).

Consequently, the proposed issuance of an incidental take permit for the construction, operation, maintenance, and decommissioning of the High Desert Solar Project will not adversely affect recovery of the desert tortoise. The translocation of desert tortoises to a conservation area and the acquisition of private lands within a conservation area are beneficial to the recovery of the desert tortoise.

Conclusion

After reviewing the current status of the desert tortoise, the environmental baseline for the action area, the effects of the proposed activities, and the cumulative effects, it is our biological opinion that the proposed action is not likely to jeopardize the continued existence of the desert tortoise. We have reached this conclusion for the following reasons:

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1. The proposed action is not likely to affect measurably the reproductive capacity of desert tortoises.

2. The proposed action is not likely to appreciably reduce the number of desert tortoises within the action area and, by extension, throughout the range of the desert tortoise.

3. The proposed action will not decrease the distribution of the desert tortoise.

4. The proposed action is not likely to adversely affect recovery of the desert tortoise.

INCIDENTAL TAKE STATEMENT

Section 9 of the Act and Federal regulation pursuant to section 4(d) of the Act prohibit the take of endangered and threatened species, respectively, without special exemption. Take is defined as to harass, harm, pursue, hunt, shoot, wound, kill, trap, capture or collect, or to attempt to engage in any such conduct. Harm is further defined by the Service to include significant habitat modification or degradation that results in death or injury to listed species by significantly impairing essential behavioral patterns, including breeding, feeding, or sheltering. Incidental take is defined as take that is incidental to, and not the purpose of, the carrying out of an otherwise lawful activity. Under the terms of section 7(b)(4) and section 7(o)(2), taking that is incidental to and not the purpose of the agency action is not considered to be prohibited taking under the Act provided that such taking is in compliance with the terms and conditions of this incidental take statement and occurs as a result of the action as proposed.

The measures described below are non-discretionary. The Service must make them binding conditions of its incidental take permit to HDSI. The Service has a continuing duty to regulate the activities covered by this incidental take statement. If the Service fails to implement the terms and conditions of the incidental take statement, the protective coverage of section 7(o)(2) may lapse. To monitor the impact of incidental take, the Service must ensure that HDSI reports the progress of its action and the impact on the species to the Service as specified in the incidental take statement (50 CFR402.14(i)93)).

Because work within waters of the United States comprises a minor and temporary component of the proposed action and HDSI is required to implement all of the protective measures in its habitat conservation plan and the Service’s incidental take permit, the Service has not identified any reasonable and prudent measures with regard to the Corps.

CONSTRUCTION

We anticipate the take of all desert tortoises in the project area. We anticipate that most desert tortoises in the project area will be captured, as the form of take, and translocated to the recipient site. Desert tortoises that are not detected during clearance surveys prior to construction may be killed or wounded; because of the difficulty in finding small desert tortoises, we expect that most of these individuals are likely to be killed or wounded during construction.

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For the purposes of our analysis, we estimates that approximately 24 desert tortoises (4 large, 19 small) reside in that area; we expect that we have overestimated the number of individuals that are present. We are unable to state precisely how many desert tortoises are present within the project area for several reasons. Desert tortoises are cryptic (i.e., individuals spend much of their lives underground or concealed under shrubs), they are inactive in years of low rainfall, and their numbers and distribution within the action area may have changed since the surveys were completed because of hatchings, deaths, immigration, and emigration. The numbers of hatchlings and eggs are even more difficult to quantify because of their small size, the location of eggs underground, and the fact that their numbers vary depending on the season; that is, at one time of the year, eggs are present but they become hatchlings later in the year.

Determining the amount or extent of the forms in which the take is likely to occur (killed, injured, or captured) is also difficult. As we noted previously, HDSI is likely to capture and translocate most of the large individuals within this area. Construction is likely to kill or wound few large desert tortoises because our prior experience is that the proposed avoidance and minimization measures will be effective. However, occasionally even larger animals remain undetected during clearance surveys and are likely to be killed or wounded during construction. HDSI is also likely to find and translocate some of the small desert tortoises; they are unlikely to detect eggs.

Using the total number of individuals within the site of the solar facility as the anticipated level of take in the form of desert tortoises that are killed or wounded because of the proposed action would be inappropriate because we fully expect that HDSI will capture and translocate numerous individuals. Therefore, we anticipate that the number of individuals killed or wounded resulting from the proposed action will be a subset of the number of desert tortoises estimated to be within the project area. Because HDSI is not likely to find every dead or wounded desert tortoise within the project area, the number of dead or wounded individuals that are found likely will be a subset of the number that are killed or wounded.

For these reasons, we will consider that HDSI exceeded the amount or extent of take if more than two large desert tortoises are killed within the project area. We used large desert tortoises to establish this amount or extent of take because small desert tortoises are difficult to find and the method by which we calculate their abundance contains more assumptions and therefore more potential for variation than does our method for predicting the number of large desert tortoises. Therefore, if HDSI finds more than two dead or wounded large desert tortoises within the project area, the Service must re-initiate formal consultation.

We are not establishing a re-initiation criterion for the number of desert tortoises translocated from the project area because HDSI has agreed to translocate all desert tortoises it finds in the project area and not merely those in harm’s way. We consider this a beneficial effect of the proposed action.

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Operation, Maintenance, and Decommissioning

We anticipate that operation, maintenance, and decommissioning are likely to kill few, if any, desert tortoises because of the low number of desert tortoises in the general area of the project and because HDSI will implement measures to protect desert tortoises during these activities. Additionally, operations and maintenance generally involves a low level of activity and decommissioning would occur largely within a fenced area. Last, we expect that this portion of the desert will support few, if any, desert tortoises in the future. We cannot predict how many desert tortoises HDSI is likely to encounter because these animals would have moved into the area from offsite habitat. Incidental take would occur in the form of capture, kill, or wound.

Translocation and Restoration Activities

HDSI’s activities with regard to translocation and restoration on the mitigation lands have the potential to take desert tortoises in the form of capture, kill, or wound. We anticipate that restoration activities may infrequently require the capture of desert tortoises to move them from harm’s way. We expect that moving desert tortoises from harm’s way at the mitigation site will occur infrequently because the workers should be able to avoid most desert tortoises. We are not establishing a re-initiation criterion for the number of desert tortoises moved from harm’s way because we expect it will occur infrequently and will not kill or injure desert tortoises.

Activities associated with translocation and restoration have low potential to kill or wound desert tortoises, primarily through stepping on them or striking them with vehicles during travel. We cannot predict how many desert tortoises HDSI will encounter during these activities and therefore cannot predict how many desert tortoises may be killed or wounded. Because HDSI will use only qualified individuals to conduct these activities, we expect that these activities are likely to take few desert tortoises. The Service will re-initiate formal consultation if more than two desert tortoises are killed or wounded by these activities.

REASONABLE AND PRUDENT MEASURE

The Service believes the following reasonable and prudent measure is necessary and appropriate to minimize take of desert tortoises during the construction, operation, maintenance, and decommissioning of the High Desert Solar Project.

The Service must condition the incidental take permit to require HDSI to allow any desert tortoises that void their bladders during any phase of the project to rehydrate.

Our evaluation of the proposed action includes consideration of the minimization and mitigation measures proposed by HDSI in its habitat conservation plan. Consequently, any changes in these measures may constitute a modification of the proposed action that causes an effect to the desert tortoise that was not considered in the biological opinion and require re-initiation of consultation, pursuant to the implementing regulations of the section 7(a)(2) of the Endangered Species Act (50 CFR 402.16).

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TERMS AND CONDITIONS

To be exempt from the prohibitions of section 9 of the Act, the Service must condition the incidental take permit with the following term and condition, which implements the reasonable and prudent measure described in the previous section.

The Service must include the following non-discretionary term and condition in the incidental take permit to HDSI:

HDSI must rehydrate any desert tortoise that voids its bladder during handling. HDSI must maintain Service-approved biosecurity protocols when handling desert tortoises; these procedures include but are not limited to avoiding cross-contamination of supplies and of desert tortoises, and to properly disinfecting all sampling gear. HDSI will rehydrate the desert tortoise:

1. In a clean, biosecure container.

2. For a minimum of 20 minutes in a quiet protected area.

3. In water level that is no higher than the lower jaw of the animal.

4. In lukewarm water.

5. HDSI must weigh the desert tortoise before and after the soaking and record the weight.

REPORTING REQUIREMENTS

The reporting section of the habitat conservation plan, which we have included as part of the proposed action, adequately describes the reporting requirements. The Service must ensure that HDSI abides by these elements of that section.

DISPOSITION OF DEAD OR INJURED DESERT TORTOISES

Measure DT-12 of the habitat conservation plan adequately describes the manner in which HDSI will handle dead or injured desert tortoises.

CONSERVATION RECOMMENDATIONS

Section 7(a)(1) of the Act directs Federal agencies to use their authorities to further the purposes of the Act by carrying out conservation programs for the benefit of endangered and threatened species. Conservation recommendations are discretionary agency activities to minimize or avoid adverse effects of a proposed action on listed species or critical habitat, help implement recovery plans, or to develop information.

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We recommend that the Service require HDSI to mark any desert tortoise that it translocates in accordance with the Desert Tortoise Recovery Office’s protocol. This marking will allow the Service to track the translocated desert tortoises in the future, if we encounter them during range-wide sampling.

RE-INITIATION NOTICE

This concludes formal consultation on the Service’s proposed issuance of an incidental take permit to HDSI for the construction, operation, maintenance, and decommissioning of the High Desert Solar Project. As provided in 50 CFR 402.16, re-initiation of formal consultation is required where discretionary Federal involvement or control over the action has been retained or is authorized by law and:

1. If the amount or extent of taking specified in the incidental take statement is exceeded;

2. If new information reveals effects of the action that may affect listed species or critical habitat in a manner or to an extent not previously considered;

3. If the identified action is subsequently modified in a manner that causes an effect to the listed species or critical habitat that was not considered in the biological opinion; or

4. If a new species is listed or critical habitat designated that may be affected by the identified action.

If you have any questions, please contact Raymond Bransfield of my staff at ray_bransfield@fws.gov or 805-677-3398.

Appendices

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LITERATURE CITED

AECOM. 2019. Final low effect habitat conservation plan. High Desert Solar Project, Victorville, San Bernardino County, California. Dated June. Prepared for Dennis Corn, HDSI, LLC, Chicago, Illinois. San Diego, California.

Allison, L. 2014. Personal communication. Electronic mail regarding range-wide population trends. Dated May 5. Desert tortoise monitoring coordinator, Desert Tortoise Recovery Office, U.S. Fish and Wildlife Service. Reno, Nevada.

Allison, L. 2019. Personal communication. Electronic mail regarding extrapolation of range-wide population trends. Dated September 20. Desert tortoise monitoring coordinator, Desert Tortoise Recovery Office, U.S. Fish and Wildlife Service. Reno, Nevada.

Allison, L.J., and A.M. McLuckie. 2018. Population trends in Mojave desert tortoises (Gopherus agassizii). Herpetological Conservation and Biology 13(2):433-452.

Averill-Murray, R.C. 2002. Effects on survival of desert tortoises (Gopherus agassizii) urinating during handling. Chelonian Conservation and Biology 4(2):430-435.

Averill-Murray, R.C., C.R. Darst, N. Strout, and M. Wong. 2013. Conserving population linkages for the Mojave desert tortoise (Gopherus agassizii). Herpetological Conservation and Biology 8(1):1-15.

Boarman, W.I. 2002. Threats to desert tortoise populations: a critical review of the literature. Western Ecological Research Center, U.S. Geological Survey. Riverside, California.

[Bureau] Bureau of Land Management. 2015. Desert Renewable Energy Conservation Plan. Proposed land use plan amendment and final environmental impact statement. Dated October. Sacramento, California.

[Bureau] Bureau of Land Management. 2016. Desert Renewable Energy Conservation Plan. Land use plan amendment to the California Desert Conservation Area Plan, Bishop Resource Management Plan, and Bakersfield Resource Management Plan. Sacramento, California.

Burroughs, M. 2013. Personal communication. Electronic transmittal of comments on the draft biological opinion for the Stateline and Silver State South proposed solar projects. Dated September 23. Fish and Wildlife Biologist, Southern Nevada Field Office, U.S. Fish and Wildlife Service. Las Vegas, Nevada.

Christensen, J.H., B. Hewitson, A.Busuioc, A. Chen, X. Gao, R. Held, R. Jones, R.K. Kolli, W.K. Kwon, R. Laprise, V. Magana Rueda, L. Mearns, C.G. Menendez, J. Räisänen, A. Rinke, A. Sarr, P. Whetton, R. Arritt, R. Benestad, M. Beniston, D. Bromwich, D. Caya, J. Comiso, R. de Elia, and K. Dethloff, 2007. Regional climate projections, Climate

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Change, 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, University Press, Cambridge, Chapter 11, ISBN: 978-0-521-88009-1.

[Corps] U.S. Army Corps of Engineers. 2019. Section 7 consultation request letter. Dated June 10. North Coast Branch, Regulatory Division, Ventura Field Office Los Angeles District. Ventura, California.

Darst, C. 2014. Personal communication. EXCEL file regarding calculations of modeled desert tortoise habitat by recovery unit with impervious surfaces. Dated May 14. Desert Tortoise Recovery Office, U.S. Fish and Wildlife Service. Reno, Nevada.

Drake, K.K., T.C. Esque, K.E. Nussear, C. Aiello, P. Emblidge, and P.A. Medica. 2010. An annual report for desert tortoise translocation research at the Fort Irwin Southern Expansion Translocation Area. Las Vegas Field Station, Western Ecological Research Center, U.S. Geological Survey. Henderson, Nevada.

Drake, K.K., KE. Nussear, T.C. Esque, AM. Barber, KM. Vittum, P.A. Medica, C.R. Tracy, and K.W. Hunter. 2012. Does translocation influence physiological stress in the desert tortoise? Animal Conservation doi:lO.l l l l/j.1469-1795.2012.00549.x.

Drake, K.K., L. Bowen, K.E. Nussear, T.C. Esque, A.J. Berger, N.A. Custer, S.C. Waters, J.D. Johnson, A.K.Miles, and R.L. Lewison. 2016. Negative impacts of invasive plants on conservation of sensitive desert wildlife. Ecosphere 7(10): Article e01531.

ECORP Consulting, Inc. 2019. Desert tortoise translocation plan. High Desert Solar Project, San

Bernardino County, California. Dated June. Submitted to HDSI, LLC, Chicago, IllinoisRedlands, California.

Ennen, J.R., J.E. Lovich, K.P. Meyer, C. Bjurlin, and T.R. Arundel. 2012. Nesting ecology of a population of Gopherus agassizii at a utility-scale wind energy facility in Southern California. Copeia 2:222-228.

Esque, T.C., K.E. Nussear, KK. Drake, AD. Walde, KH. Berry, R.C. Averill-Murray, A.P. Woodman, W.I. Boarman, P.A. Medica, J. Mack, and J.S. Heaton. 2010. Effects of subsidized predators, resource variability, and human population density on desert tortoise populations in the Mojave Desert, USA. Endangered Species Research 12(2):167-177.

Field, K.J., C.R. Tracy, P.A. Medica, R.W. Marlow, and P.S. Corn. 2007. Return to the wild: Translocation as a tool in conservation of the desert tortoise (Gopherus agassizii). Biological Conservation 136:232-245.

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Fry, J.A., G. Xian, S. Jin, J.A. Dewitz, C.G. Homer, L. Yang, C.A. Barnes, N.D. Herold, and J.D. Wickham. 2011. National Land Cover Database 2006. Photographic Engineering and Remote Sensing 77(9):858-864.

Henen, B.T. 2019. Personal communication. Electronic mail regarding the number of desert tortoises found on the Marine Corps Air Ground Combat Center at the Twentynine Palms expansion project. Dated January 25. U.S. Ecologist, Marine Corps Air Ground Combat Center, U.S. Marine Corps. Twentynine Palms, California.

Hinderle, D., R.L. Lewison, A.D. Walde, D. Deutschman, and W.I. Boarman. 2015. The effects of homing and movement behaviors on translocation: desert tortoises in the western Mojave Desert. Journal of Wildlife Management 79(1):137–147; 2015; DOI: 10.1002/jwmg.823.

Kelly, M.P. U.S. 2019. Personal communication. Electronic mail regarding the U.S. Fish and Wildlife Service’s biological opinion for the proposed action. Dated September 26. Counsel, Base Realignment and Closure, Office of the Deputy General Counsel (Installations, Energy and Environment), U.S Air Force. McClellan, California.

Latch, E.K., W.I. Boarman, A. Walde, R.C. Fleischer. 2011. Fine-scale analysis reveals cryptic landscape genetic structure in desert tortoises. PLoS ONE 6(11):e27794. doi:10.1371/journal.pone.0027794.

Longshore, K.M., J.R. Jaeger, and J.M. Sappington. 2003. Desert tortoise (Gopherus agassizii) survival at two eastern Mojave Desert sites: death by short-term drought? Journal of Herpetology 37(1):169-177.

Lovich, J.E., and D. Bainbridge. 1999. Anthropogenic degradation of the southern California desert ecosystem and prospects for natural recovery and restoration. Environmental Management 24(3):309–326.

Nussear, K.E. 2004. Mechanistic investigation of the distributional limits of the desert tortoise Gopherus agassizii. Dissertation. University of Nevada. Reno, Nevada.

Nussear, K.E., T.C. Esque, R.D. Inman, L. Gass, K.A. Thomas, C.S.A. Wallace, J.B. Blainey, D.M. Miller, and R.H. Webb. 2009. Modeling habitat of the desert tortoise (Gopherus agassizii) in the Mojave and parts of the Sonoran Deserts of California, Nevada, Utah, and Arizona. U.S. Geological Survey Open-File Report 2009-1102.

Nussear, K.E., C.R. Tracy, P.A. Medica, D.S. Wilson, R.W. Marlow, and P.S. Corn. 2012. Translocation as a conservation tool for Agassiz’s desert tortoises: Survivorship, reproduction, and movements. The Journal of Wildlife Management; DOI: 10.1002/jwmg.390.

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Oftedal, O.T., S. Hillard, and D.J. Morafka. 2002. Selective spring foraging by juvenile desert tortoises (Gopherus agassizii) in the Mojave Desert: Evidence of an adaptive nutritional strategy. Chelonian Conservation and Biology 4:341-352.

Ross, E. 2019. Personal communication. Electronic mail regarding the U.S. Fish and Wildlife Service’s biological opinion for the proposed action. Dated September 25. Project Manager, North Coast Branch, Regulatory Division, Ventura Field Office Los Angeles District, U.S. Army Corps of Engineers. Ventura, California.

Scherer, R.D., M.L. Farnsworth, and B.G. Dickson. 2016. Preliminary survival analysis for ISEGS Mojave desert tortoises: April 2012 – April 2016. For the project entitled:

eterminants of survival for translocated Mojave desert tortoises in the Ivanpah Valley, California. Conservation Science Partners. Truckee, California.

[Service] U.S. Fish and Wildlife Service. 1994. Desert tortoise (Mojave population) recovery Plan. Portland, Oregon.

[Service] U.S. Fish and Wildlife Service. 1998. Biological opinion for the transfer of property at George Air Force Base, California (1-8-97-F-55). Letter to Chief, Environmental Planning Division, Environmental Conservation and Planning Directorate, HQ AFEE/ECP, Brooks Air Force Base, Texas. Dated April 8. From Field Supervisor, Ventura Fish and Wildlife Office. Ventura, California.

[Service] U.S. Fish and Wildlife Service. 2010. Mojave population of the desert tortoise (Gopherus agassizii) 5-year review: summary and evaluation. Desert Tortoise Recovery Office. Reno, Nevada.

[Service] U.S. Fish and Wildlife Service. 2011. Revised recovery plan for the Mojave population of the desert tortoise (Gopherus agassizii). Sacramento, California.

[Service] U.S. Fish and Wildlife Service. 2012. Biological opinion for the proposed addition of maneuver training lands at Fort Irwin, California (8-8-11-F-38R). Letter to Chief of Staff, Headquarters, National Training Center and Fort Irwin, Fort Irwin, California. Dated April 27. From Field Supervisor, Ventura Fish and Wildlife Office. Ventura, California.

[Service] U.S. Fish and Wildlife Service. 2015. Update on Mojave desert tortoise population trends. Dated June 19. Desert Tortoise Recovery Office. Reno, Nevada.

[Service] U.S. Fish and Wildlife Service. 2016. Biological opinion for the proposed land use plan amendment under the Desert Renewable Energy Plan. Memorandum to Deputy State Director, Division of Natural Resources, Bureau of Land Management, Sacramento, California. Dated August 16. From Field Supervisor, Carlsbad Fish and Wildlife Office. Carlsbad, California.

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[Service] U.S. Fish and Wildlife Service. 2017. Biological opinion for land acquisition and airspace establishment, Twentynine Palms, California. Letter to Lieutenant Colonel of Marine Air Ground Task Force Training Command, Twentynine Palms, California. Dated January 31. From Field Supervisor, Carlsbad Fish and Wildlife Office. Carlsbad, California.

[Service] U.S. Fish and Wildlife Service. 2018a. Translocation of Mojave desert tortoises from project sites: Plan development guidance. Dated February. Desert Tortoise Recovery Office. Reno, Nevada.

[Service] U.S. Fish and Wildlife Service. 2018b. Preparing for any action that may occur within the range of the Mojave desert tortoise ( Gopherus agassizii ). Dated October 26. Desert Tortoise Recovery Office. Reno, Nevada.

[Service] U.S. Fish and Wildlife Service. 2018c. Range-wide monitoring of the Mojave desert tortoise (Gopherus agassizii): 2017 annual reporting. Dated February. Desert Tortoise Recovery Office. Reno, Nevada.

[Service] U.S. Fish and Wildlife Service. 2019. Biological opinion for proposed activities within the Cuddeback Range land withdrawal at the Naval Air Weapons Station, China Lake, California (FWS-INY-KRN-SBR-16B0219-19F0246). Memorandum to Head, Environmental Management, Division Naval Air Weapons Station, China Lake, California. Dated March 21, 2019. From Acting Field Supervisor, Carlsbad Fish and Wildlife Office. Carlsbad, California.

Tracy, C.R., R. Averill-Murray, W.I. Boarman, D. Delehanty, J. Heaton, E. McCoy, D. Morafka, K. Nussear, B. Hagerty, and P. Medica. 2004. Desert tortoise recovery plan assessment. Prepared for the U.S. Fish and Wildlife Service. Reno, Nevada.

Turner, F.B., K.H. Berry, D.C. Randall, and G.C. White. 1987. Population ecology of the desert tortoise at Goffs, California. University of California, Los Aneles, California; Bureau of Land Management, Riverside, California; and Colorado State University, Fort Collins, Colorado.

Unknown author. 2015. Long-term management plan for the Cuddeback-Kramer Preserve. Dated July 7.

Walde, A.D., and W.I. Boarman. 2013. Draft final report. Desert tortoise translocation, monitoring, and research within the southern expansion area and translocation areas of Fort Irwin, California. Dated May 13. Prepared for National Training Center and Fort Irwin Directorate of Public Works, Fort Irwin, California. Walde Research and Environmental Consulting, Atascadero, California, and Conservation Science Research and Consulting, Spring Valley, California.

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Wasz, K.M. 2019. Personal communication. Electronic mail regarding the estimated number of desert tortoises at the project site. Dated September 12. Biology Manager/Senior Biologist ECORP Consulting, Inc. Redlands, California.

Wilson, D.S., D.J. Morafka, C.R. Tracy, and K.A. Nagy. 1999. Winter activity of juvenile desert tortoises (Gopherus agassizii) in the Mojave Desert. Journal of Herpetology 33(3):496-501.

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APPENDIX A

1. Mojave population of the desert tortoise (Gopherus agassizii). Desert Tortoise 5-year review: summary and evaluation.

2. Solar projects for which the U.S. Fish and Wildlife Service has issued biological opinions or incidental take permit

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SOLAR PROJECTS FOR WHICH THE U.S. FISH AND WILDLIFE SERVICE HAS ISSUED BIOLOGICAL OPINIONS OR INCIDENTAL TAKE PERMITS