The Influence of Late Quaternary Climate Change on the Ecology and Evolutionary Dynamics of Small Mammalian Herbivores

本研究探讨了晚第四纪木鼠对温度变化的演化响应。该项目包括在美国西南部的洞穴遗址进行工作，使用木獭化石或碎片。砾石由植物碎片、粪便颗粒和其他嵌入结晶尿液中的物质组成（“琥珀”）；当洞穴被遮蔽时，它们可以保存数千年。放射性碳定年粪便颗粒的测量用于估计体型；对大多数哺乳动物来说，体型对环境温度很敏感。在接下来的一年里，我们将调查我们的研究系统中可能存在问题的采样和统计维度，包括用现代动物进行研究，以检查粪便的沉积和组成。生物可能通过适应或局部灭绝来应对人为的气候变化。然而，这种反应的时间、规模和性质仍不清楚。过去的一万年可以说是我们了解人为气候变化可能造成的影响的最佳代表。通过研究第四纪晚期不同地点的不同种类的小型啮齿动物，并估计发生不同类型进化反应的热阈值，我们可能能够更好地了解未来气候变化将如何影响哺乳动物种群。

0212370SmithThis research investigates the evolutionary response of woodrats totemperature change over the late Quaternary. The project involves work at cave sites in the southwestern United States, using fossilized woodrat middens or debrispiles. Middens consist of plant fragments, fecal pellets and othermaterials embedded in crystalized urine ("amberat"); when sheltered incaves they persist for thousands of years. Measurements of radiocarbon-datedfecal pellets are used to estimate body size; for most mammals, size is sensitive toenvironmental temperature. Over the next year, we will investigate anumber of potentially problematic sampling and statistical dimensions ofour study system, including conducting studies with modern animals toexamine midden deposition and composition.Organisms may respond to anthropogenic climate change by adapting or goinglocally extinct. However, the timing, magnitude and nature of suchresponses remains unclear. The past ten thousand years are arguably thebest proxy we have for understanding the likely effects of anthropogenicclimate change. By examining different species of small rodents atdifferent locations within their range over the late Quaternary, andestimating the thermal thresholds at which different types of evolutionaryresponses occur, we may be able to better understand how future climatechange will impact mammalian populations.