The Impact of Late Quaternary Climate Change on Mammals Along an Elevational Gradient

这项研究沿着严格的海拔和环境梯度调查了过去 15,000 年来 Neotoma（林鼠）对气候变化的反应。在更新世期间，曼利湖覆盖了死亡谷的大部分地区。全新世中期的突然排水导致温度和干旱的急剧变化。如今，该地区是西半球最热、最干燥的地区。通过结合实地考察、博物馆标本检查和古化石收集，该项目将重建谷底和附近山坡（-84 至 3400m）的动物不同的进化历史。 研究人员预测林鼠物种的适应能力与地点海拔和当地小气候有关的根本差异。预测的反应包括：i）超过温度阈值时局部灭绝，ii）新适应的产生，例如新的生活史，以及iii）形态改变，例如体型的表型变化。这项工作更广泛的影响包括能够描述温度变化的幅度和速度、地理范围内的位置以及阐明的响应类型之间的关系。这些有关生物体对过去气候变化的反应的信息对于研究人为变暖的科学家来说非常宝贵。此外，该项目将生成高质量的空间和时间解析气候代理，可以与其他古数据集成。晚第四纪气候的表征和解释是政府和地球科学机构的一项重大研究工作。

This study investigates the response of Neotoma (woodrats) to climatic change over the last 15,000 years along a severe elevational and environmental gradient. During the Pleistocene, lake Manly covered much of Death Valley; its abrupt draining in the mid-Holocene led to dramatic shifts in temperature and aridity. Today this area is the hottest and driest in the Western Hemisphere. By combining fieldwork, examination of museum specimens, and collection of paleofossils, this project will reconstruct the divergent evolutionary histories of animals from the Valley floor and along a nearby mountain gradient (-84 to 3400m). The investigators predict fundamental differences in the adaptive abilities of woodrat species related to elevation of the site and local microclimate. Predicted responses include: i) local extirpation when temperature thresholds are exceeded, ii) generation of novel adaptations, such as new life histories, and iii) morphological alterations, such as phenotypic changes in body size. The broader impacts of the work include the ability to characterize the relationship between the magnitude and rapidity of temperature shifts, the position in the geographic range, and the type of elucidated response. Such information about the responses of organisms to past climate change is invaluable for scientists studying anthropogenic warming. Moreover, the project will generate a high quality spatial and temporally resolved climate proxy that can be integrated with other paleodata. The characterization and interpretation of late Quaternary climates is a major research effort of governmental and geoscience agencies.