RANGE DYNAMICS OF NORTH AMERICAN AVIAN SPECIES AS A FUNCTION OF RECENT CLIMATE CHANGE: TESTS AND PREDICTIVE MODELING

J. Andrew Royle, and John R. Sauer, Patuxent Wildlife Research Center, Southeastern Regional Assessment Project, U.S. Geological Survey, 12100 Beech Forest Road, Laurel, MD 20708 USA; Adam J. Terando, and Alexa J. McKerrow, US Geological Survey, North Carolina Cooperative Fish and Wildlife Research Unit, Southeastern Regional Assessment Project, Department of Biology, North Carolina State University, Campus Box 7617, Raleigh, NC 27695 USA; James B. Grand and Kevin Kleiner

US Geological Survey, Alabama Cooperative Wildlife Research Unit, Southeastern Regional Assessment Project, 3301 Forestry and Wildlife Sciences Building, Auburn University, Auburn, AL 36849;

Effects of global climate change on the distribution and abundance of organisms are expected to be pervasive, with virtually all ecological systems influenced to some extent. Such changes are not expected to be uniform for all organisms and locations, and we can make predictions about the relative magnitudes of change for different situations. With appropriate data and methodology, we can then test these predictions and develop models to predict future change. We propose to study N. A. landbirds and to use data from the North American Breeding Bird Survey (BBS), together with newly developed analytical methodology, to test hypotheses about recent changes in species ranges corresponding to climate change during the last 2 decades. Our primary predictions involve geographic range and the expectation that, on average, recent changes in range location in response to climate change should be largest at locations near southern and northern species range boundaries. In particular, we predict higher rates of local species extinction, lower rates of local colonization, and greater declines in species occupancy near southern range boundaries. We predict higher rates of local colonization, lower rates of local extinction, and greater increases in species occupancy near northern range boundaries. These predictions will be tested against differing predictions for local occupancy dynamics during previous decades and at other geographic locations (near western and eastern range boundaries; central portions of ranges). We will test these predictions using BBS data with occupancy estimation approaches that incorporate occupancy state of nearby locations. The degree to which colonization of new locations depends on the occupancy of neighboring locations will be an important determinant of the rate of range expansion. These analyses will provide the basis for dynamic models that predict future range dynamics in response to predicted climate change.