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Interior West 



Overview 



The articles in this section 

 reveal the critical need for 

 ecosystem science to direct ecosystem manage- 

 ment in areas ranging from the Colorado 

 Rockies, south to the Colorado Plateau, west to 

 the Great Basin and the Pacific Northwest, and 

 north to the Greater Yellowstone Ecosystem. 

 Ecosystems in the hiterior West are challenged 

 by severe climatic fluctuations superimposed on 

 rapidly changing land-use patterns and anthro- 

 pogenic (human-caused) threats. Because sci- 

 entists and resource managers now recognize 

 the prohibitive cost and difficulty of a species- 

 by-species approach to biological conservation 

 and wise stewardship, their efforts are moving 

 increasingly toward an ecosystem and land- 

 scape approach to conservation. 



My colleagues and I begin this section by 

 identifying and quantifying anthropogenic 

 threats to ecosystem integrity in Rocky 

 Mountain National Park and the Colorado 

 Rockies (Stohlgren et al.). The article by 

 Schullery continues this common theme by 

 describing alarming trends in plant and animal 

 populations in the Greater Yellowstone 

 Ecosystem. By taking a broad view of sub- 

 alpine forest dynamics in the Pacific Northwest, 

 Peterson shows that treeline communities may 

 be adversely intluenced by rapid environmental 

 change. Warshall examines the southwestern 



sky island ecosystems (the mountaintops of the 

 Great Basin) with respect to threats from non- 

 indigenous species, recreation and military 

 practices, and fire-management activities. 



The status and trends of many plant and ani- 

 mal populations are uncertain in the Interior 

 West. Scoppettone and Rissler. however, report 

 successful population increases of the endan- 

 gered cui-ui fish (Chasmistes cujus) in Pyramid 

 Lake, Nevada: the population has doubled 

 between 1990 and 1993. Mueller and Marsh 

 focus on how loss of critical riparian habitat 

 through water development, pollution, and the 

 introduction of nonindigenous species have 

 caused population declines of the threatened 

 and endangered razorback sucker {Xyraiicheu 

 te.xaniis) and bonytail {Gila elegans) in the 

 Colorado River Basin. The article by Drost and 

 Deshler on the diversity of reptiles and amphib- 

 ians on the Colorado Plateau reminds us that 

 much inventory and monitoring work lies 

 ahead. Van Riper III et al. also remind us that 

 human activities in the past (e.g., pesticide use, 

 water diversion, and the introduction of non- 

 indigenous trout) continue to affect the status 

 and trends of bald eagle {Haliueetiis leiico- 

 cephalus) populations on the southern Colorado 

 Plateau. And, Willey demonstrates that 90% of 

 the threatened Mexican spotted owl (Sirix occi- 

 dentalis litcida) habitat on the Colorado Plateau 



