PARENT SESSION

Community Ecology 3 -- Session Chair: Catherin Schwemm-- Van Duzer Theater

SMALL MAMMAL COMMUNITY ASSEMBLY: INSIGHTS FROM PALEONTOLOGICAL AND EXPERIMENTAL DATA. Paula A. Spaeth and Elizabeth A. Hadly. Stanford University, Department of Biological Sciences, Stanford, CA.

ABSTRACT- Lamar Cave, a late-Holocene paleontological site in Yellowstone National Park, spans 3,500 years and records changes in the abundances of voles, Microtus montanus and M. longicaudus. Changes in the abundance of these species are inversely related and correlated with climatic events (such as the Medieval Warm Period) throughout the fossil record. Unfortunately, historical patterns do not allow the effects of climate change and interspecific interactions on the local abundance of voles to be examined independently. Therefore, I conducted competitive removal experiments along an environmental gradient in the Greater Yellowstone Ecosystem to examine the relative influences of physical environmental factors and interspecific interactions on the abundance and distribution of voles of the genus Microtus. The results suggest that competition has played a large role in shaping the abundance and distribution of these vole taxa. These experiments, in combination with fossil data, shed light on past processes (climatic and biotic), and provide valuable insight into future climate-driven change in temperate mammalian communities. Additionally, the persistence of ecological interactions over millennial time-scales suggests that biotic interactions may play a key role in the evolution of small mammals.

KEY WORDS: community, ecology, Microtus , assembly