Biological Resources
Corresponding page numbers in the DEIS:
Summary of Impacts: pp. 349-415; Environmental Consequences: pp. 385-415
The proposed action would result in the direct loss or conversion of 6,380 to 6,461 acres of habitat and may indirectly impact up to 145,190 acres, which may have the potential to impact animal behavior. For the majority of the species, the impact is not expected to have far-reaching consequences for population viability. However, because of the magnitude, intensity, length, and around-the-clock timing of the project, all special status plants and animals that occur in the area are expected to be impacted.
Some species would be directly and indirectly impacted, including nine species federally listed as threatened or endangered under the Endangered Species Act (Chiricahua leopard frog, Gila chub, Gila topminnow, Huachuca water umbel, jaguar, lesser long-nosed bat, ocelot, Pima pineapple cactus, and southwestern willow flycatcher) and four species federally listed as candidate under the Endangered Species Act (desert tortoise, northern Mexican gartersnake, Rosemont talussnail, and western yellow-billed cuckoo). For two special status plant species (beardless chinchweed and Coleman’s coral-root), all action alternatives may result in a downward trend toward Federal listing as threatened or endangered or in a loss of population viability. For 7 special status plant and 13 special status animal species, all action alternatives may impact individuals of these species but are not likely to result in a downward trend toward Federal listing as threatened or endangered or in a loss of population viability of these species.
There would be significant vegetation losses and changes in the area, resulting in a decrease in nesting, overwintering, foraging, and roosting habitat for dozens of species of migratory and resident birds. Every species currently occupying the area would potentially experience a reduction in individuals and population size.
Current activities such as livestock grazing, combined with the proposed project, would cumulatively contribute to a general loss of native grassland and woodland habitats; noise, air, and light pollution; and degradation of riparian habitats.
An unknown number of acres of animal movement corridors and linkage areas would potentially be impacted, including the potential to: (1) modify and/or fragment animal movements between mountain ranges; (2) reduce local connectivity between habitats; (3) increase animal roadkills from the transportation system and increased traffic; and (4) result in a loss of genetic flow.
The alteration of surface and subsurface hydrology from the pit and other mining related operations may result in the loss of riparian habitat and the fragmentation of riparian habitat and corridors.
Riparian habitat that could be affected includes 490 acres of hydroriparian or mesoriparian habitat along Cienega Creek, 471 acres of xeroriparian habitat along Davidson Canyon, up to 204 acres of mesoriparian habitat along Davidson Canyon, 58 acres of hydroriparian or mesoriparian habitat along Empire Gulch, and 140 acres of hydroriparian or mesoriparian habitat along Gardner Canyon.
