Dissertation Research: Assessing the Strength of Competition in the Fossil Record

Stanford University, Stanford CA

Investigators

Abstract

The project investigates the interspecific ecological interactions between small mammals over the past three millennia in the Greater Yellowstone Ecosystem (GYE), a center of extraordinary biodiversity in the heart of North America. By integrating the recent fossil record and modern ecological experiments, it will be possible to determine how competition structures modern and ancient biological communities. The overarching goal is to reveal whether these interactions are similar in modern and ancient communities and to predict the importance of these interactions in the future. Modern experiments were conducted to describe the ecological mechanisms governing the abundance of voles sharing habitats across an environmental gradient. Results of these experiments are used to predict abundances over time of the same species in the GYE fossil record. Using fossils, the relationship between the outcome of the competitive interaction and climatic change is explored and new insights have begun to emerge. These data suggest that (1) ancient and modern interspecific interactions are similar; and (2) past fluctuations in climate directly influenced the abundance of one species, which indirectly influenced the abundance of the competitor. NSF funding will enable broader sampling of multiple fossil locales across time in order to establish the generalities of our preliminary results. Results to date point to the cascading effects of climate change in biological communities, which is ameliorated by species coexistence. Further, this study illustrates the importance of understanding how modern species responded to past climatic change in order to predict how species will respond to future climatic change.