Collaborative Research: Responses of Desert Endotherms to Rapid Recent Climate Change

气候变化对动植物分布的影响存在相当大的不确定性。大多数关于近期气候变化对物种地理范围的研究都是基于计算机模型的预测，而不是实地研究的测量反应。这项研究采取了一种截然不同的多层次方法，通过使用具有所需精度、地理和时间尺度以及观测到的气候变化幅度的历史记录和标本，对气候和非气候因素对物种地理分布变化的直接和间接影响产生了重要的见解。这项研究将重新调查美国西南部70多年前最后一次调查的现场，这不仅将促进我们对环境变化的理解，而且将为比较未来的变化建立一个新的基准。联邦土地管理机构将受益于更多地了解敏感物种的状况和野生动物对气候变化的反应。收集到的标本和录音将用于辅助研究。结果将通过演讲、受欢迎的媒体和博物馆展览向公众广泛推广，包括圣地亚哥自然历史博物馆和加利福尼亚州奥克兰博物馆的新展品。国家公园管理局科学和教育办公室将通过视频和播客广泛传播结果，以培训他们的翻译人员了解环境变化的生物影响，并为他们的游客中心提供解释材料。本科生、研究生和博士后研究人员将参与这项研究，学习领域和实验室技术、自然历史、生理方法和建模。结果和数据将通过网站和在线数据库与科学家和普通公众共享。该项目将对1908-1945年间采样的地点进行重新调查，以研究20世纪气候变化对索诺兰、莫哈韦和大盆地沙漠中小型哺乳动物和鸟类群落的影响。这些地区在过去50年里显著变暖，年平均气温上升到2摄氏度。这项研究将通过以下方式促进对动物对气候变化反应的理解：开发新的模型，通过将气候与温度和水分胁迫的重要生理阈值联系起来，机械地预测物种的范围；开发新的测试，以检查气候变化是否导致物种单独改变其地理范围，或者整个物种群落是否发生类似的变化；以及测试物种的身体大小和饮食是否对气候变化做出了反应。鸟类和哺乳动物将在105个地点进行重新调查。将收集音频和实物凭单样本，以供将来重新分析。将收集鸟类和哺乳动物头骨的标准形态数据。碳和氮同位素的比率将从组织中测量。多物种占有率模型将考虑到历史和当前调查中的可探测性，以制定对物种在当地的殖民和灭绝以及群落组成变化的无偏见估计，以响应场地一级的特征。将对12种哺乳动物进行热应激和高于热中和区上限的热应激测量，以开发可验证的热应激模型。

Considerable uncertainty exists about the effects of changing climates on the distributions of plants and animals. Most studies of recent climate change on species' geographic ranges are based on projections from computer models rather than measured responses from field studies. This research takes a very different and multi-tiered approach by using historical records and specimens with the necessary precision, geographic and temporal scale, and magnitude of observed climate change to produce important insights into the direct and indirect effects of climatic and nonclimatic factors on changes in species' geographic distributions. This research will resurvey field sites in the southwest United States last surveyed more than 70 years ago, which will not only advance our understanding of environmental changes but will establish a new benchmark for comparison of future changes. Federal land-management agencies will benefit from greater knowledge of the status of sensitive species and wildlife responses to climate change. Specimens and audio recordings collected will be available for ancillary studies. Results will be extended broadly to the public through talks, popular press and media, and museum displays, including new exhibits of the San Diego Natural History Museum and the Oakland Museum of California. The National Park Service Science and Education Office will distribute results widely through videos and podcasts to train their interpreters on the biological effects of environmental change and to provide interpretive materials for their visitor centers. Undergraduates, graduate student and postdoctoral researchers will participate in this study, learning field and lab techniques, natural history, physiological methods and modeling. Results and data will be shared with scientists and the general public through websites and online databases. This project will resurvey sites that were sampled from 1908-1945 to examine the impact of 20th century climate change on small mammal and bird communities in Sonoran, Mojave, and Great Basin deserts. These areas have warmed greatly over the last 50 years, with the average annual temperatures increasing up to 2°C. The research will advance understanding of animal responses to climate change by: developing new models that mechanistically project species' ranges by linking climate through important physiological thresholds of temperature and water stress; developing novel tests to examine whether climate change results in species shifting their geographic ranges individually or whether whole communities of species shift similarly; and testing if body sizes and diets of species have responded to climate change. Birds and mammals will be resurveyed at 105 sites. Both audio and physical voucher specimens will be collected and made available for future reanalysis. Standard morphological data will be collected for birds and mammal skulls. Ratios of carbon and nitrogen isotopes will be measured from tissues. Multispecies occupancy models will account for detectability in historical and current surveys to develop unbiased estimators of local colonization and extinction of species and changes in community composition in response to site-level characteristics. Measures of thermal and hydric stress at and above the upper limit of the thermal neutral zone will be made for 12 species of mammals to develop models of heat stress that can be validated.