| The Pacific pocket mouse (Perognathus longimembris pacificus) is a federally listed endangered species and the Los Angeles pocket mouse (P. l. brevinasus) is a Species of Special Concern in California. Each little pocket mouse subspecies is the smallest member of its respective rodent community in Southern California coastal sage scrub or chaparral habitat. Multiple species that occupy similar niches in a community compete directly and indirectly for shared resources. Differences between species in interference competition ability that counteract a difference in exploitative competition ability may allow species to achieve stable coexistence in these habitats. Through a series of experiments, we are investigating the mechanisms that allow these small, specialist foragers to maintain stable populations in their respective communities of larger generalist competitors. In Experiment 1, we study interference competition and interspecific territoriality through staging dyadic encounters in the field. In Experiment 2, we investigate exploitative competition through cache pilfering trials. Finally, we are conducting monthly monitoring to understand both spatial and temporal niche partitioning. Through these studies we aim to clarify the interspecific relationships that structure these small mammal communities and maintain species diversity. |