THE AUTHORS 



RESEARCH SUMMARY 



DEAN E. MEDIN is a research wildlife biologist with the 

 Intermountain Research Station at the Forestry Sciences 

 Laboratory in Boise, ID. He earned a B.S. degree in forest 

 management from Colorado State University in 1957, an 

 M.S. degree in wildlife management from Colorado State 

 University in 1959, and a Ph.D. degree in range ecosystems 

 from Colorado State University in 1976. His research has 

 included studies in mule deer ecology, big-game range im- 

 provement, mule deer population modeling, and nongame 

 bird and small mammal ecology and habitat management. 



WARREN P. CLARY is project leader of the Intermountain 

 Station's Riparian-Stream Ecology and Management re- 

 search work unit at Boise, ID. He received a B.S. degree 

 in agriculture from the University of Nebraska and an M.S. 

 degree in range management and a Ph.D. degree in botany 

 (plant ecology) from Colorado State University. He joined 

 the Forest Service in 1960 and has conducted research on 

 forested and nonforested rangelands in Arizona, Louisiana, 

 Utah, Idaho, Oregon, and Nevada. 



ACKNOWLEDGMENTS 



We gratefully acknowledge the field and office assistance 

 of John W. Kinney, Sherri A. Brown, Justine L. Wirch, and 

 Patrick V. Turner. Craig R. Contor designed the cover 

 illustration. 



We compared breeding bird and small mammal popula- 

 tions between a riparian habitat seasonally grazed by cattle 

 and a comparable adjacent riparian habitat protected from 

 grazing for the previous 14 years by a fenced exclosure. 

 The 122-ha exclosure, constructed in 1975, straddles 

 Summit Creek in east-central Idaho. Bird populations were 

 assessed by spot-mapping methods in the spring of 1989. 

 Small mammal populations were compared by removal 

 trapping in late summer of both 1988 and 1989. 



There was little difference between grazed and ungrazed 

 habitats in total breeding bird density. But total bird biomass, 

 bird species richness, and bird species diversity were 1 .87, 

 1.75, and 1.62 times higher, respectively, in the grazed habi- 

 tat. The differences were almost entirely due to the presence 

 of shorebirds — killdeer, willets, and long-billed curlews — as 

 breeders only on the grazed area. Those species are fre- 

 quently associated with the low vegetational profiles of 

 grazed habitats. Other species, including savannah spar- 

 rows and red-winged blackbirds, were more numerous in 

 the ungrazed habitat. 



Small mammal populations were almost a third higher on 

 the grazed area than on the ungrazed area. Conversely, 

 both species richness and species diversity of small mammal 

 communities were higher in the ungrazed habitat. Deer mice 

 were the most frequently trapped small mammal on both the 

 grazed and ungrazed areas. They were almost twice as 

 common in the grazed habitat. Montane voles were found in 

 highest densities in the ungrazed habitat. Those two species 

 accounted for 94 percent of the total number of individual 

 animals trapped at Summit Creek. Other species, including 

 vagrant shrews, water shrews, and Great Basin pocket mice, 

 were caught irregularly and in smaller numbers. 



The use of trade or firm names in this publication is for 

 reader information and does not imply endorsement 

 by the U.S. Department of Agriculture of any product 

 or service. 



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 324 25th Street 

 Ogden, UT 84401 



