Great Basin Naturalist Memoirs Volume 2 Intermountain Biogeography: A Symposium Article 14 3-1-1978 The theory of insular biogeography and the distribution of boreal birds and mammals James H. Brown Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona 85721 Follow this and additional works at: https://scholarsarchive.byu.edu/gbnm Recommended Citation Brown, James H. (1978) "The theory of insular biogeography and the distribution of boreal birds and mammals," Great Basin Naturalist Memoirs: Vol. 2 , Article 14. Available at: https://scholarsarchive.byu.edu/gbnm/vol2/iss1/14 This Article is brought to you for free and open access by the Western North American Naturalist Publications at BYU ScholarsArchive. It has been accepted for inclusion in Great Basin Naturalist Memoirs by an authorized editor of BYU ScholarsArchive. For more information, please contact
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[email protected]. THE THEORY OF INSULAR BIOGEOGRAPHY AND THE DISTRIBUTION OF BOREAL BIRDS AND MAMMALS James H. Brown 1 Abstract.—The present paper compares the distribution of boreal birds and mammals among the isolated mountain ranges of the Great Basin and relates those patterns to the developing theory of insular biogeography. The results indicate that the distribution of permanent resident bird species represents an approximate equilib- rium between contemporary rates of colonization and extinction. A shallow slope of the species-area curve (Z = 0.165), no significant reduction in numbers of species as a function of insular isolation (distance to nearest conti- nent), and a strong dependence of species diversity on habitat diversity all suggest that immigration rates of bo- real birds are sufficiently high to maintain populations on almost all islands where there are appropriate habitats.