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

点击翻译按钮获取中文摘要

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.