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

这项研究调查了过去15,000年来，沿着严重的海拔和环境梯度，新托玛(伍德拉斯)对气候变化的响应。在更新世，曼利湖覆盖了死亡谷的大部分；在全新世中期，它的突然排水导致了温度和干旱的戏剧性变化。今天，这个地区是西半球最热、最干燥的地区。通过结合田野调查、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米至3400米)上动物的不同进化史。研究人员预测，与地点海拔和当地小气候有关的林木物种的适应能力存在根本差异。预测的反应包括：i)当温度超过阈值时局部切除，ii)产生新的适应，如新的生活史，以及iii)形态改变，如身体大小的表型变化。这项工作的更广泛影响包括能够表征温度变化的大小和快速之间的关系、地理范围内的位置以及阐明的反应的类型。这些关于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是非常宝贵的。此外，该项目将生成一个高质量的空间和时间分辨率气候指标，可以与其他古数据相结合。晚第四纪气候的描述和解释是政府和地球科学机构的一项主要研究工作。

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.