Environmental Engineering Reference
In-Depth Information
9
Wildlife and Anthropogenic Changes
in the Arid
Southwest
Brian K. Sullivan, David R. Van Haverbeke, and Carol Chambers
CONTENTS
9.1 Introduction ........................................................................................................................ 169
9.2 Anthropogenic Change ..................................................................................................... 170
9.3 Habitat Loss ........................................................................................................................ 170
9.4 Habitat Fragmentation ...................................................................................................... 173
9.4.1 Habitat Alteration .................................................................................................. 174
9.4.2 Habitat Loss and Alteration along the Colorado and Rio Grande Rivers ..... 177
9.4.3 Habitat Fragmentation and Alteration in Urbanized Sonoran Desert ........... 181
9.4.4 Conservation Policy ............................................................................................... 183
9.4.5 Future Directions ................................................................................................... 184
References ..................................................................................................................................... 186
9.1
Introduction
Deserts are ecosystems of low rainfall and high temperatures (see Chapter 3). A surprising
variety of arid landscapes occur in southwestern North America: the botanically diverse
Sonoran Desert receives precipitation in both the winter and summer, while the relatively
homogenous Great Basin Desert to the north receives much of its annual rainfall in the form
of snow during the cold winter months. Animals need cover, water, and food to survive
and reproduce, and in deserts, adequate habitat to satisfy these needs is often limited.
Even fully aquatic organisms, such as fish and some amphibians, must adapt to extremes
of water temperature, salinity, and flooding that result from rare but intense rainfall events
in arid ecosystems.
1,2
Relatively rare aquatic ecosystems in deserts provide habitat to
many amphibian and fish species but also draw hundreds of species of birds.
1
Although
southwestern desert ecosystems appear sparsely inhabited, even the hottest areas have a
diverse wildlife community that includes dozens of species of mammals, birds, reptiles,
and even amphibians.
3
Over the past few decades, biologists have come to appreciate that
these desert landscapes are especially vulnerable to environmental disturbance wrought
by humankind.
169
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