International Research Fellowship Program: Population Sex Ratio Bias: Influences of Climate and Consequences for Extinction Risk

[0965096 .格雷森国际研究奖学金计划使美国科学家和工程师能够在国外进行9至24个月的研究。该计划的奖励为联合研究提供了机会，并利用独特或互补的设施、专业知识和国外的实验条件。该奖项将支持Kristine L. Grayson博士与新西兰维多利亚大学Nicola J. Nelson博士开展为期16个月的研究。了解气候变化对生态的影响是一个紧迫的研究重点。温度显著影响种群动态的能力在具有温度依赖性性别决定（TSD）的物种中尤为明显。即使是很小的气候变化也有可能改变巢穴的温度，使整个种群的性别比例发生偏差。该研究项目测量了气候对一种患有TSD的爬行动物物种——鳄蜥（Sphenodon punctatus）种群结构的影响，并确定性别比例偏差是否会增加灭绝的风险。首先，他们利用新西兰北部小岛屿上的鳄蜥种群来测量自然纬度梯度上的当前人口性别比。各岛屿间种群结构的变化正在与以下因素进行研究：1)过去的温度制度，2)可用的热巢微生境，以及3)雌性状况和繁殖力。其次，他们使用实验方法来确定短期内男性偏向的性别比例对女性形态和状态的影响，以及对女性形态和状态的影响。最后，他们将他们的数据与鳄蜥研究小组的长期人口数据结合起来，形成一个投影矩阵模型。这个模型将使他们能够探索有关性别比例偏差与种群过程之间联系的理论问题，并对鳄蜥种群生存能力进行现实的估计。他们的研究测试了关于气温上升和可用的热筑巢栖息地对自然种群中成年性别比例偏差程度的影响的假设。他们使用了一个具有Ib型TSD的物种，在这些物种中，温暖的巢穴会产生雄性后代，来测试关于种群性别比例在将个体互动和社会系统与种群的增长、衰退或灭绝联系起来方面所起作用的理论预测。此外，它们的种群数据将提供非常需要的信息，以指导重要的鳄蜥残余种群的保护，鳄蜥是一种具有进化、文化和国际意义的濒危物种。该奖学金还包括通过Spinyback信托基金支持当地小学科学教育的机会，并与北部岛屿的m<s:1>奥里部落合作。

0965096GraysonThe International Research Fellowship Program enables U.S. scientists and engineers to conduct nine to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.This award will support a sixteen-month research fellowship by Dr. Kristine L. Grayson to work with Dr. Nicola J. Nelson at Victoria University in New Zealand. Understanding the ecological impacts of climate change is an urgent research priority. The ability of temperature to dramatically impact population dynamics is particularly apparent in species with temperature-dependent sex determination (TSD). Even small shifts in climate have the potential to alter nest temperatures and bias the sex ratio of an entire population. This research project measures the influence of climate on population structure in a reptile species with TSD, the tuatara (Sphenodon punctatus), and determines if a biased sex ratio amplifies the risk of extinction. First, they are using small island populations of tuatara across northern New Zealand to measure current population sex ratios across a natural latitudinal gradient. The variation in population structure across islands is being examined in relation to 1) past temperature regimes, 2) available thermal nesting microhabitats, and 3) female condition and fecundity. Second, they are using an experimental approach to determine the interactions and behavior altered by a male-biased sex ratio over the short-term and the impact on female morphology and condition over the long-term. Finally, they are combining their data with long-term population data from the tuatara research group to inform a projection matrix model. This model will allow them to explore theoretical questions about the links between a biased sex ratio and population processes, as well as generate realistic estimations of tuatara population viability. Their research tests hypotheses about the influence of rising air temperatures and available thermal nesting habitats on the degree of adult sex ratio bias across natural populations. They use a species with Type Ib TSD, where warmer nests produce male offspring, to test theoretical predictions about the role of population sex ratio in linking individual interactions and the social system to the growth, decline, or extinction of a population. In addition, their population data will provide much needed information to guide the conservation of important remnant populations of tuatara, a threatened species of evolutionary, cultural, and international significance. This fellowship also includes opportunities to support local primary science education through the Spinyback Trust and work with the northern island tribes of the Mâori.