Sonoran Desert Tortoise ( Source: GSRC)

RVSS Upgrade Program (New Towers) Final EA

September 2012

and warmer in winter than outside temperatures. Tortoises require loose soil in which to excavate shallow burrows below rocks and boulders, but they may also use rock crevices which they may or may not be able to modify. Tortoises occasionally burrow under vegetation; less often they dig soil burrows on more or less open slopes, and also use caliche caves in incised arroyo banks. They will also rest directly under live or dead vegetation without constructing a burrow.

Activity begins in the spring as temperatures warm, and then decreases as the season moves into the summer drought in May and June (Averill-Murray and Klug 2000). Much more time is spent inactive in burrows, where they conserve water and energy. The onset of the summer monsoon season signals the beginning of peak tortoise activity, dramatically rising in early August and peaking during August-September (Averill-Murray and Klug 2000). Activity decreases sharply after mid-October, as tortoises withdraw to winter hibernacula, which are shelters similar to those they use during activity seasons (Averill-Murray and Klug 2000). Even during the winter, some individuals may bask, move or even forage on warm winter days. Females may terminate hibernation as early as late February, while some males may remain inactive through the entire spring.

Sonoran desert tortoises eat a variety of annual and perennial grasses, forbs and succulents. Sonoran tortoise forage includes dicot annuals, grasses, herbaceous perennials, trees and shrubs, subshrubs/woody vines and succulents (ADGF 2001). The most common food items include the woody vine (Janusia gracilis) and various mallows (Malvaceae spp.) (AGFD 2001).

Although the disturbance footprint of the Proposed Action does not support suitable habitat for this species, the landscape surrounding TCA-AJO-0523 and TCA-AJO-0553 supports potential Sonoran desert tortoise habitat. However, no sign of Sonoran desert tortoise was observed at the proposed tower sites during the biological surveys.

3.7.1.2 State-Listed Species

The ANHP maintains a list of species with special status in Arizona. The ANHP list includes flora and fauna whose occurrence in Arizona is or may be in jeopardy or that have known or perceived threats or population declines (AGFD 2011b). The ANHP list is provided in

Appendix E. Similarly, the CDFG Biogeographic Data Branch maintains the California Natural Diversity Database of state-listed endangered and threatened animals (CDFG 2011), and

endangered, threatened and rare plants (CDFG 2012) of California. The CDFG list of state- protected species is provided in Appendix E. These species are not necessarily the same as those protected under the ESA.

The project area could be considered suitable habitat for various state-listed species.

Specifically, one Arizona state-listed species, the flat-tailed horned lizard (Phynosoma macallii), has the potential to occur within or near the project area. However, no state-listed species for Yuma, Santa Cruz or Pima counties in Arizona, or Imperial County, California, were observed during the pedestrian surveys.

RVSS Upgrade Program (New Towers) Final EA

September 2012

Flat-tailed Horned Lizard

The flat-tailed horned lizard is a small to medium- sized horned lizard with a snout-to-vent length of 2.3 to 3.2 inches (Photograph 3-13). The flat-tailed horned lizard is found in the lower Colorado River Valley subdivision of the Sonoran Desertscrub and has a very limited distribution in Northern Mexico, Arizona and California (Flat-tailed Horned Lizard Interagency Coordinating Committee 2003). This species is known from a variety of habitats; however, in Arizona, it seems to be restricted to sandy and hardpan flats dominated by creosote bush (Flat-tailed Horned Lizard Interagency Coordinating Committee 2003). AGFD currently includes the flat-tailed horned lizard on its draft list

of wildlife of special concern. This designation affords no legal Federal protection to the

species, but is used in planning to encourage habitat conservation and management consideration (Flat-tailed Horned Lizard Interagency Coordinating Committee 2003). Collecting or killing flat-tailed horned lizards is prohibited in both Arizona and California, except by special permit (Flat-tailed Horned Lizard Interagency Coordinating Committee 2003). The flat-tailed horned lizard is currently afforded protection under the Rangewide Management Strategy (Flat-tailed Horned Lizard Interagency Coordinating Committee 2003). Because BLM and Reclamation are signatories on the Rangewide Management Strategy, any surface-disturbing projects on their lands is subject to the provisions in the Rangewide Management Strategy (Flat-tailed Horned Lizard Interagency Coordinating Committee 2003). YUM-YUS-0539, YUM-YUS-0543, YUM- YUS-0547, YUM-YUS-0549, YUM-YUS-0573, YUM-YUS-0575 and YUM-YUS-0577 are within the range of the flat-tailed horned lizard (Figure 3-11). Two of the tower sites (YUM- YUS-0543 and YUM-YUS-0547) are located in the Yuma Desert Flat-tailed Horned Lizard Management Area. These sites contain suitable flat-tailed horned lizard habitat and are on lands managed by agencies designated as signatories of the flat-tailed horned lizard conservation agreement.

3.7.2 Environmental Consequences 3.7.2.1 Proposed Action

No verifiable occurrences of any Federally listed species were made within the project area during the biological survey. Consultation with the USFWS under Section 7 of the ESA has been completed. CBP received concurrence from USFWS that the Proposed Action may affect, but would not likely adversely affect Mexican spotted owl, southwestern willow flycatcher, jaguar, lesser long-nosed bat, ocelot and Chiricahua leopard frog. Likewise, the Proposed Action may affect, but is not likely adversely affect, designated Critical Habitat for the Mexican spotted owl. The Proposed Action is not likely to adversely modify proposed Critical Habitat for the southwestern willow flycatcher or affect designated Critical Habitat for the southwestern willow flycatcher or Chiricahua leopard frog. The Proposed Action may affect, would not likely

adversely affect Sonoran pronghorn. Concurrence from USFWS has not been received for the Sonoran pronghorn. At CBP’s discretion, consultation was not completed for the Sonoran pronghorn since the towers on OPCNM will not be constructed at this time.

Photograph 3-13. Flat-tailed Horned Lizard