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the Phoenix metropolitan area indicate that increased traffic over the past two decades
has led to increased mortality.* 88 There may be a trade-off within urbanized populations
in which higher prey numbers are coupled with increased mortality due to roadways and
other unnatural sources of morbidity.
With respect to activity area (i.e., home range size), a number of birds and mammals have
smaller home ranges in areas of increased human activity. † As noted earlier, some have
speculated that this is from increased prey availability in urbanized landscapes, and others
have suggested that barriers (e.g., roadways) act to constrain home range size. In a number
of corvid birds, home range area decreases with increasing urbanization, apparently as a
result of increased food resources. A smaller number of studies have documented changes
in behavior with increasing urbanization, such as a shift to nocturnal activity for large
carnivores in urban settings. For example, coyotes avoided disturbed habitats altogether
and limited their movements to corridors of natural habitat and moved less rapidly and
less often with increasing urbanization. 89 Like the Gila monsters, some mammalian and
avian predators may benefit from increased prey availability while experiencing higher
levels of mortality associated with road traffic in urbanized landscapes.
9.4.4 Conservation Policy
Many of the investigations of anthropogenic effects on wildlife of the Southwest reviewed
earlier were stimulated by federal and state conservation policies. For example, the Heritage
Program, administered by the Arizona Game and Fish Department, funded the investiga-
tions on Arizona striped whiptails, Arizona toads, common chuckwallas, Gila monsters,
and tiger rattlesnakes, in addition to many other valuable studies of urbanization and other
affects on southwestern wildlife. A host of conservation policies, including the Endangered
Species Act (ESA) and National Environmental Policy Act (NEPA), led to research critical
to our present ability to conserve wildlife of North America. 90 However, despite impressive
growth in conservation policy, and funding for basic and applied research over the past
half century, the loss of biodiversity in the United States has continued. 90 Although there
have been a number of impressive successes with respect to endangered species recovery,
such as the bald eagle and peregrine falcon, North America has the highest proportion of
non-native invasive species making up our current flora and fauna and dozens of species
awaiting listing as endangered or threatened. North American conservation policy has not
stopped biodiversity loss in part because it is insufficiently valued by society. 91 For exam-
ple, the costs of setting aside critical habitat typically ignore benefits accruing to recreation
or clean water generation. Recent analyses have also revealed that conservation policy can
sometimes be as influenced by politics as by biology: scientific evidence can be ignored,
and the political orientation of state representatives in part determines the number of spe-
cies listed as endangered or threatened on a state-by-state basis. 91,92
State and federal agency personnel have begun moving toward grassroots approaches
focused on integrating conservation efforts with local stakeholders (e.g., ranchers, landowners)
while managing wildlife. Many view this as an appealing development, but it has been
coupled with a movement to eliminate postdecisional appeals (i.e., litigation), a mainstay of
nonagency conservationists (e.g., the Tucson based Center for Biological Diversity) attempting
to combat perceived inaction or mismanagement on the part of agencies. 93 Ideally, one would
hope that all conservation concerns could be addressed at the outset (predecisional), but
* B.K. Sullivan, unpublished data.
† See review in Kwiatkowski et al. 21