9307 ‎(2)‎

• UCREFRP Catalog Number: 9307
• Author: Germaine, S. S.
• Title: Relationships of Birds, Lizards, and Nocturnal Rodents to Their Habitat in the Greater Tucson Area, Arizona.
• USFW Year: 1995.
• USFW - Doc Type: Phoenix, AZ.
• Copyright Material: NO

Relationships of Birds, Lizards, and Nocturnal Rodents to Their Habitat
in the Greater Tucson Area, Arizona
Stephen S. Germaine
Abstract: I examined population and community descriptors of 3 wildlife assemblages across the
residential gradient from undisturbed-natural to highly developed land in Tucson, Arizona, from
March 1994 through February 1995. Breeding birds were sampled in 334 random plots, and
wintering birds and lizards were sampled in subsets of 305 and 130 plots, respectively. In
addition, I sampled nocturnal rodents at 8 sites representing 3 housing densities. Land cover
type, habitat structure, plant species composition, and distances from population refugia were
measured in all plots. I identified habitat associations for breeding bird, wintering bird, and
lizard species. Housing density best explained the variation in species richness for non-native,
native, and an indicator guild of breeding birds, and for lizards. The percent of paved areas,
exotic, upper Sonoran, and undisturbed riparian vegetation in plots, and distance from
undisturbed washes also predicted bird and lizard species richness. Lizard abundance was best
explained by the amount of lower Sonoran vegetation and undisturbed riparian vegetation
within plots. House mice (Mus musculus) were the only nocturnal rodents encountered in high
density (7.5 houses/ha) housing areas. Two of the native rodent species were less abundant in
the high density control than in low density (0.5 houses/ha) areas. While rodent species
richness did not differ significantly among levels of housing density, total abundance was lower
in the high density housing and control. Development strategies for optimizing urban wildlife
habitat in Tucson in the future are discussed.
INTRODUCTION
Development of rural lands surrounding
metropolitan areas has become a major factor
contributing to the destruction of natural habitats.
Residential and commercial development of rural
areas is occurring in most states, and is expected
to continue for several decades. For example,
over 80% of the human population in Arizona
lives in metropolitan areas; these areas are rapidly
expanding and fragmenting native habitat.
Arizona is currently the 5th fastest growing state
in the United States (O'Leary Morgan et al. 1991),
and Tucson is the 3rd fastest growing city in
Arizona (Hazard and Burchell 1991).
As urban development progresses outward,
native habitats become incorporated into the
suburban matrix, and many suburban areas
become increasingly isolated from contiguous
blocks of native habitat. In these developing
areas, blocks of native vegetation become
fragmented and insularized, creating a patchwork
matrix of native habitat islands that have been
altered by varying degrees from their natural state
As urban development continues, distances
between these islands and the edge of the
undeveloped areas "mainland" (MacArthur and
Wilson 1967) increase. Mainland is here defined
as the undeveloped desert surrounding Tucson
which serves as a population source for the native
species. Small isolated blocks of natural habitat
are of questionable value to native wildlife
(Wilcove 1985, Soule et al. 1988, Bolger et al.
1991).
As island to mainland distance increases,
immigration from source populations generally
decreases, and only those species with high
dispersal capabilities may reach the more isolated
islands. Also, as island size decreases extinction
rates increase, due to the island's diminished
ability to support as many individuals per species
(MacArthur and Wilson 1963, Lynch and
Whigham 1984). Isolated blocks (islands) are often
structurally and floristically altered by human and
vehicular traffic, trash dumping, competition from
introduced plants, modified precipitation runoff
patterns, and otherwise altered by the presence of
feral predators (Whitcomb 1977, Adams 1994).
Natural habitat corridors in developed areas
are usually confined to riparian zones or
powerline rights-of-way where the vegetation is
often degraded (modified from natural conditions)
and frequently fragmented by roads or other
human-made obstacles. While probably not
limiting bird dispersal, roads can have major
detrimental effects on the dispersal of
herpetofauna (Minton 1968, Gibbs et al. 1971) and
small mammals (Oxley et al. 1974). Furthermore,
the utility of corridors as important wildlife
dispersal routes has been seriously questioned
(Simberloff et al. 1992}.
STEPHEN S. GERMAINE 1995 ARIZONA GAME fr FISH DEPARTMENT, TECH. REP. 20