Vegetation Zones of the Southwest - Design with the Desert: Conservation and Sustainable Development - page 147

Canada. Common species in the these mixed-conifer forests include Douglas fir, white
fir ( Abies concolor ), aspen, and at the higher elevation portions also include other species
of fir ( Abies ) and spruce ( Picea ) including blue spruce ( Picea pungens ). Above the forest
type Alpine Tundra occurs to a very limited extent. The climate of this type is defined not
by precipitation but by temperature and will not be considered in detail here due to the
limited extent of its occurrence in the southwestern region.
7.4 Conclusion
The landscape diversity that exists within the borders of the North American deserts is
immense as is the number of plant and animal species that inhabit these communities.
These communities are at once both very robust and very fragile. They are robust in that
the component species have evolved attributes (life histories) that allow them to survive
under very harsh conditions of limited and undependable rainfall. On the other hand,
these same life histories have not made them either resistant or resilient in the face of
new anthropogenic environmental challenges. The challenges—including old challenges
such as grazing and the newer challenges of urbanization and invasive species—will be
discussed in detail in later chapters. The challenge of development is to proceed and meet
the needs of human populations while at the same time protecting and preserving the
unique species and communities of the deserts. While this is not a small challenge, it is
critical if the life of the desert is to continue.
References
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2. UNEP, World Atlas of Desertification (New York: John Wiley & Sons, 1992).
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University Press, 1964).
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1979/1980.
5. Whitford, W., Ecology of Desert Systems (New York: Academic Press, 2002).
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U.K.: John Wiley & Sons, 2001).
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Report RM-41, map, 1:1,000,000 scale (Fort Collins, CO: U.S. Forest Service, Rocky Mountain
Forest and Range Experiment Station, 1977).
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