WILDLIFE RESOURCES 1 Affected Environment

The vegetative communities of the Sonoran Desert biome within the Yuma and Ajo project area typically support an abundance of small mammals and reptiles, which provide forage for several species of predatory mammals and birds. Although the biome supports a diverse assemblage of wildlife, the general lack of vegetative structure, low plant diversity and extremely limited availability of water make the Sonoran desertscrub and creosote-sage communities particularly harsh for wildlife. A list of wildlife species observed during the biological resources surveys conducted by GSRC is provided in Appendix D.

Vegetation Community Tower Site Impacts on Vegetation

Permanent Temporary Arizona Upland Sonoran

Desertscrub

TCA-AJO-0523

TCA-AJO-0553 14.62 8.67

Chihuahuan Desertscrub TCA-DGL-0557

TCA-DGL-0565 6.12 3.03 Semidesert Grassland TCA-NCO-0525 TCA-NCO-0529 TCA-NCO-0567 TCA-NGL-0511 27.75 11.12

Madrean Evergreen Woodland

TCA-NGL-0505 TCA-NGL-0507 TCA-NGL-0509 TCA-NGL-0555

5.80 4.5

Lower Colorado River Sonoran Desertscrub YUM-YUS-0533 YUM-YUS-0535 YUM-YUS-0543 YUM-YUS-0547 YUM-YUS-0571 YUM-YUS-0573 YUM-YUS-0575 YUM-YUS-0577 10.19 9.74 TOTAL 64.5 37.1

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3.6.2 Environmental Consequences 3.6.2.1 Proposed Action

The permanent loss of up to 64.5 acres and temporary degradation of approximately 37.1 acres of vegetation communities would have short-term, minor impacts on wildlife. Soil disturbance and operation of heavy equipment could result in the direct loss of less mobile individuals such as lizards, snakes and ground-dwelling species such as mice and rats. However, most wildlife would avoid any direct harm by escaping to surrounding habitat. The direct degradation and loss of habitat could also impact burrows and nests, as well as cover, forage and other important wildlife resources. The loss of these resources would result in the displacement of individuals that would then be forced to compete with other wildlife for the remaining resources. Although this resulting competition for resources could result in a reduction of total population size, such a reduction would be extremely minimal in relation to total population size and would not result in long-term effects on the sustainability of any wildlife species. BMPs outlined in Section 5.0 would reduce disturbance and loss of wildlife habitats.

The Proposed Action would have a long-term, minor adverse effect on migratory birds. There is a possibility that the proposed RVSS towers could pose hazards to migratory birds; however, since the monopole tower type does not use guy wires, the potential for adverse impacts is greatly reduced. Furthermore, tower construction would adhere to the USFWS interim guidelines and FAA guidelines and would be designed to reduce impacts on migratory birds (USFWS 2000). Similar to the effect of habitat degradation and loss on the sustainability of wildlife populations, the number and extent of bird strikes in relation to the size of migratory bird populations and the extent of the migratory flyway would be minor and would not affect sustainability of migratory bird populations in the region.

Noise associated with tower and road construction, road improvements and road maintenance would result in temporary, minor impacts on wildlife. Elevated noise levels associated with construction and maintenance activities would only occur during the duration of these activities. The effects of this disturbance would include temporary avoidance of work areas and

competition for unaffected resources. Blasting activities associated with improvements on the approach road to TCA-DGL-0565 may cause egg breakage or general flight responses from wildlife. BMPs as outlined in Section 5.0 would reduce noise associated with operation of heavy equipment.

Noise levels associated with the operation and maintenance of the towers would have a

permanent, minor impact on wildlife species. The permanent increase in noise levels associated with operation of the proposed tower sites (i.e., backup generators) would be sporadic, only occurring when this equipment is operating. It is anticipated that wildlife would become accustomed to these intermittent and minimal increases in noise, and that subsequent avoidance of tower sites and any adjacent habitats would be minor.

The use of spotlights at 12 proposed tower sites (see Table 2-3) could also disturb wildlife

adjacent to the proposed towers. However, on average, the spotlights would only be used twice a night for a period of approximately 5 minutes for each use. Similar to impacts associated with the permanent increase in noise, it is anticipated that some wildlife would become accustomed to these intermittent increases in light. Subsequent avoidance of tower sites and any adjacent

RVSS Upgrade Program (New Towers) Final EA

September 2012

habitats would be minimal. Ultimately, the effects of increased noise and light could displace some individual wildlife species and result in localized competition for resources. However, the extent of these impacts would not decrease the sustainability of wildlife populations in the region.

The Proposed Action could result in indirect and long-term beneficial impacts on wildlife by reducing the adverse impacts of CBV activities in the project area (such as, trampled vegetation and habitat, compacted soils, collapsed subterranean tunnels and burrows, garbage and human waste and wildfires). The proposed RVSS towers would enhance CBP’s detection capabilities and increase the efficiency of operational activities within the area of tower coverage.

Enhancement of detection capabilities and interdiction efficiency would increase deterrence of CBV activity within the area of tower coverage.

3.6.2.2 Alternative 1

Under Alternative 1, impacts on wildlife and wildlife habitats would be similar to those

discussed for the Proposed Action; however, approximately 67.4 acres of wildlife habitat would be permanently impacted.

3.6.2.3 No Action Alternative

Under the No Action Alternative, no direct impacts on wildlife habitats would occur. CBP’s detection capabilities would not be enhanced under the No Action Alternative. Illegal off-road vehicle and pedestrian traffic would continue to disturb wildlife species, cause individuals to avoid resources in areas of high illegal traffic volume and disturb or degrade additional acres of wildlife habitat.

3.7 PROTECTED SPECIES AND CRITICAL HABITATS