PARENT SESSION
Oral Session # 75: Biodiversity II.
Presiding: K Kirkman
Thursday, August 7. 1:30 PM to 5:00 PM, SITCC Meeting Room 100.

Linking the scaling of body size distributions and the species-area relationship.

White, Ethan^*,1, Marquet, Pablo², Brown, James¹, ¹ University of New Mexico, Albuquerque, NM² Pontificia Universidad Católica de Chile, Santiago, Chile

ABSTRACT- The scaling of body size distributions (BSD) in mammals, from nearly log-uniform in local communities to the traditionally observed right-skewed modal distribution at continental scales, has received considerable attention over the last decade. It can be shown that the scaling of the body size distribution and the slopes of the species-area relationships (SAR) for the different body-size classes are directly connected. The slope of the SAR must be steepest at the modal body size class and must continue to decrease monotonically to either side of the mode in order for the observed pattern to exist. We compare the BSD scaling of birds to that previously observed for mammals and show that in birds the BSD is scale invariant and that the slope of the SAR does not change regularly with mass. This implies that there are taxonomic differences in the scaling of BSDs that are potentially due to some combination of differences between birds and mammals in dispersal limitation and/or assembly rules. The implications of these differences for elucidating the underlying processes of the SAR are discussed.

Key words: body size distribution, species-area relationship, scale