Wildlife and Anthropogenic Changes in the Arid Southwest - Design with the Desert: Conservation and Sustainable Development - page 170

FIGURE 9.2
Lookout Mountain, Phoenix Mountains, Maricopa County, Arizona. Note the absence of two habitats, open
creosote flats and tree-lined arroyos, and dominance of rocky slope habitat.
FIGURE 9.3
Mesopredators such as domestic cats are often predators in urban and suburban settings. A conservative esti-
mate predicts that a single cat kills 56 wild animals each year.
disturbs soils, even altering microclimate. 10,11 With development, the decline of large
carnivores due to habitat loss has led to increases in native (striped skunk, gray fox) and
introduced (domestic cat) mesopredators that prey on wildlife. For example, pet cats
in a small urban subdivision (∼100 residences) have been estimated to kill hundreds
of rodents, birds, and lizards (Figure 9.3). Cats presumably consume prey uncounted
in this estimate; given that activities of feral cats were not considered, these numbers
underestimate predation. 12
Birds are generally sensitive indicators of vegetation change, both composition and
structure. Housing density best explained variation in species' richness for birds in Tucson,
and housing developments with exotic vegetation did not support native species such as
black-throated sparrows, verdins, and northern flickers: high density housing results in
habitat loss for these species. Retaining and protecting native vegetation and creating
native habitat fragments throughout urban areas can help retain habitat for some wildlife
species. However, some species are sensitive to even a small degree of disturbance and will
not remain in developed areas. 10 The elf owl and the nectar-feeding lesser long-nosed bat