PARENT SESSION
Oral Session # 5: Biogeography I: Community Structure and Diversity.
Presiding: B Enquist
Monday, August 4. 8:00 AM to 11:30 AM, SITCC Meeting Room 104.

Hierarchical resource distribution lowers species diversity in a desert rodent assemblage: Impacts of individual-level processes on community structure.

Orland, Mary^*,1, Kelt, Douglas², ¹ University of California, Davis, Davis, CA, USA² University of California, Davis, Davis, CA, USA

ABSTRACT- Individual-based models have shown that a hierarchical distribution of resources among individuals in a population has the potential to significantly impact population persistence. We investigated the community-level consequences of a hierarchical resource distribution with a food supplementation experiment in a heteromyid rodent community in the Sonoran Desert of southern California. Reproduction and biomass increased dramatically, but there was no change in the density of adult rodents. There was also a decrease in species diversity and a corresponding increase in the presence of the dominant pocket mouse species with the addition of resources. Combined with the lack of change in home range size, the disproportionate numerical increase of the dominant species suggests that resources are distributed hierarchically among individuals in the community. This indicates that individual behavior can affect community level processes, and specifically that a hierarchical distribution of resources may decrease species diversity in a system with spatially heterogeneous resources.

Key words: individual variation, heteromyid, biodiversity, competition