Context Thermal traits likely mediate organismal responses to changing thermal environments. As temperatures increase, predicting species responses will depend on understanding how thermal traits vary within and among individuals and across time and space. Objectives We evaluated variation in thermal traits within and among individual Mojave Desert Tortoises, using GPS telemetry to quantify movement performance and animal-mounted sensors to measure carapace temperatures. Methods We constructed thermal performance curves (TPCs) based on movement velocity and assessed variation in associated thermal traits by sex, season, and proximity to roads. We also examined the temperature-dependence of monthly home ranges and the frequency of high-displacement movements. Results Individuals exhibited lower variation in upper critical temperatures (CT maxE ) than in other traits, such as optimum temperatures and lower critical temperatures for movement. All thermal traits varied within individuals, either by season or proximity to roads. We also found that monthly home range size and the frequency of high-displacement movements increased with the time individuals spent within their optimal temperature range; however, this effect was only apparent during months with greater rainfall. Conclusions Low standing variation in CT maxE suggests that this trait may be constrained, limiting potential changes through acclimation or selection in warming environments. Our results demonstrate the modifying effect of rainfall on temperature-space use relationships and highlight the dependence of thermal traits on ecological and landscape contexts. Field-based TPCs derived from GPS movement tracks provided ecologically-relevant estimates of thermal traits and suggest an informative framework for unifying elements of thermal biology and spatial ecology.

中文翻译：

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基于场运动的热性能曲线揭示了沙漠外温区热特性的环境依赖性

背景热特征可能介导机体对热环境变化的反应。随着温度升高，预测物种反应将取决于了解热特性如何在个体内部和个体之间以及跨时间和空间变化。目标我们评估了个体莫哈韦沙漠陆龟内部和之间热特征的变化，使用 GPS 遥测技术来量化运动性能，并使用动物安装的传感器来测量甲壳温度。方法 我们根据运动速度构建了热性能曲线 (TPC)，并根据性别、季节和道路距离评估了相关热特性的变化。我们还检查了每月家庭范围的温度依赖性和高位移运动的频率。结果 个体在上临界温度 (CT maxE ) 上的变化低于其他特征，例如运动的最佳温度和下临界温度。个体内部的所有热特征都因季节或道路距离而异。我们还发现，每个月的家庭范围大小和高位移运动的频率随着个人在最佳温度范围内度过的时间而增加；然而，这种影响仅在降雨量较大的月份才明显。结论 CT maxE 的低变异表明该特性可能受到限制，通过在变暖环境中的适应或选择来限制潜在的变化。我们的结果证明了降雨对温度-空间利用关系的影响，并强调了热特性对生态和景观环境的依赖性。源自 GPS 运动轨迹的基于现场的 TPC 提供了热特征的生态相关估计，并提出了统一热生物学和空间生态学元素的信息框架。