DISSERTATION RESEARCH: Comparative thermal physiology and evolution of Australo-papuan Eugongylus skinks: testing Janzen's hypothesis for gradients in species diversity

了解温度生理学是理解许多生物现象的必要条件，如生长的时空格局、物种多样性和范围大小。热生理学的比较研究也有助于深入了解内在生理限制如何影响物种形成的倾向，并解释宏观进化模式，如纬度多样性梯度。拟议的研究将在系统发育的背景下，研究一组相关的森林蜥蜴在广泛的纬度梯度（热带新几内亚到温带塔斯马尼亚）和山地和低地分类群之间的温度反应和特征。核心预测是，低纬度物种的热耐受宽度将比高纬度物种窄，而高海拔物种的热耐受宽度将比低海拔物种宽。将考虑与系统地理数据相关的耐热性和其他生理参数的测量，以验证热带分类群更容易由于生理限制而在地形上隔离并因此形成物种的假设。该项目旨在解释一个主要宏观进化模式的机制，即纬度多样性梯度，但它也对保护有影响。为了最大限度地减少生物多样性的丧失，必须根据脆弱性确定保护区的优先次序来管理生态系统，这需要确定控制对环境变化敏感性的因素。灵敏度是由一个物种的内在特征控制的，比如生理极限。整合生理特征的机械物种分布模型在推断可能导致范围转移或灭绝的新情况时，可能提供更大的预测能力。通过本研究估计的物种的热生理特征将被纳入这些模型，以评估哪些物种可能在即将到来的气候变化中最脆弱，从而确定保护重点。

An understanding of temperature physiology is necessary to comprehend many biological phenomena, such as temporal and spatial patterns of growth, species diversity, and range size. Comparative studies of thermal physiology also yield insight into how intrinsic physiological limits affect the propensity for speciation and explain macroevolutionary patterns, such as the latitudinal diversity gradient. The proposed research will examine temperature responses and traits for a set of related forest lizards across an extensive latitudinal gradient (tropical New Guinea to temperate Tasmania) and between montane and lowland taxa, all in a phylogenetic context. Central predictions are that thermal tolerance breadths will be narrower in species at lower than high latitudes and wider for species at high compared to low altitudes. Measurements of thermal tolerance and other physiological parameters will be considered in relation to phylogeographic data to test the hypothesis that tropical taxa are more prone to topographic isolation and hence speciation due to physiological limits. This project seeks to explicate mechanisms responsible for a major macroevolutionary pattern, the latitudinal diversity gradient, but it also has implications for conservation. To minimize biodiversity loss, ecosystems must be managed by prioritizing conservation areas based on vulnerability, which requires that factors governing sensitivity to environmental change be identified. Sensitivity is controlled by intrinsic traits of a species, such as physiological limits. Mechanistic species distribution models that integrate physiological traits may provide greater predictive power when extrapolating to novel situations likely to cause range shifts or extinctions. Thermal physiological traits of species estimated through this research will be incorporated into such models to assess which species might be most vulnerable with impending climate change and thus identify conservation priorities.