Climate change and environmental gender determination in a geographically-widespread species

气候和生境的快速变化对生物的影响是重大的科学和社会问题。对于已经濒临灭绝的物种来说，澄清这些影响的必要性尤其迫切。海龟可能是最濒危的脊椎动物，在绝大多数情况下，海龟在巢中经历的温度永久决定了后代的性别。这种依赖温度的性别决定(TSD)将通过对来自美国各地气候差异地区的彩龟野生种群的多年野外、实验室和模型研究来检验。该项目将重点测量母体筑巢行为和胚胎热敏感性的地理变化，作为患有TSD的海龟适应当地气候的潜在机制。每年，学生研究小组将在实地和实验室进行研究。这些活动将包括监测海龟的筑巢行为，评估孵化的蛋和发育的胚胎，以及记录环境和栖息地数据。然后，这些信息将被整合到尖端的计算机模型中，以阐明当地气候的变化将如何影响巢温度，从而影响后代的性别比例。反过来，模型预测将进行实验测试，以确定患有TSD的种群必须如何调整行为和/或生理，以抵消由热变化引起的任何失衡。这些综合研究应该提供一个全面的理解，即具有热敏感特征的物种可能如何适应预测气候和生境快速变化的情景。这一发现将与使用TSD保护物种特别相关。这一多年计划还将(1)建立一个广泛适用的工具，在点源(巢穴、植物根部等)的温度测量之间进行转换。(2)通过加强五年级学生的授课计划，提高对科学方法的理解；(3)继续为许多学生(包括代表性不足的少数群体、残疾人和妇女)提供第一手的科学和教育机会。

The biological impacts of rapid changes in climate and habitats are major scientific and societal concerns. The need for clarifying these effects is particularly acute for species that are already imperiled. Turtles may be the most endangered group of vertebrates and, in the vast majority, temperatures experienced in the nest permanently determine offspring sex. This temperature-dependent sex determination (TSD) will be examined with a multi-year field, laboratory, and modeling study of wild populations of the painted turtle, Chrysemys picta, from climatically-divergent locations across the United States. This project will focus on measuring geographic variation in maternal nesting behavior and embryonic thermal sensitivity as potential mechanisms used by turtles with TSD to adapt to local climates. Teams of student researchers will conduct research at the field sites and in the laboratory each year. These activities will include monitoring behavior of nesting turtles, assessing incubating eggs and developing embryos, and recording environmental and habitat data. This information then will be incorporated into cutting-edge computer models to illuminate how changes in local climate will affect nest temperature and thus offspring sex ratio. In turn, the model predictions will be tested experimentally to identify how populations with TSD must adjust behaviorally and/or physiologically to offset any imbalance induced by thermal alterations.These integrated studies should provide a comprehensive understanding of how species with thermally-sensitive traits might adjust to forecast scenarios of rapid changes in climate and habitats. The findings will be particularly germane to conservation of species with TSD. This multi-year program also will (1) build a broadly applicable tool for translating between temperature measurements at point sources (nests, plant roots, etc.) to thermal variation at the habitat level and then to regional climate, (2) improve understanding of the scientific method by enhancing a lesson plan for 5th-grade students, and (3) continue to provide first-hand scientific and educational opportunities for numerous students (including underrepresented minorities, persons with disabilities, and women).