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

该项目调查了过去三千年来大黄石生态系统（GYE）中小型哺乳动物之间的种间生态相互作用，该生态系统是北美心脏地带一个非同寻常的生物多样性中心。通过整合最近的化石记录和现代生态实验，将有可能确定竞争是如何构成现代和古代生物群落的。总体目标是揭示这些相互作用在现代和古代社区中是否相似，并预测这些相互作用在未来的重要性。现代实验描述了控制田鼠在环境梯度上共享栖息地丰度的生态机制。这些实验的结果被用来预测GYE化石记录中同一物种随时间的丰度。利用化石，研究了竞争相互作用的结果与气候变化之间的关系，并开始出现新的见解。这些数据表明：(1)古代和现代种间相互作用相似；(2)过去气候的波动直接影响了一个物种的丰度，从而间接影响了竞争对手的丰度。美国国家科学基金会的资助将使我们能够对不同时期的多个化石地点进行更广泛的采样，以确定我们初步结果的普遍性。迄今为止的研究结果表明，气候变化在生物群落中的级联效应通过物种共存而得到改善。此外，这项研究说明了了解现代物种如何应对过去的气候变化，以预测物种如何应对未来的气候变化的重要性。

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.