Data from: Some like it hot: from individual to population responses of an arboreal arid-zone gecko to local and distant climate

Accumulating evidence has demonstrated considerable impact of climate change on biodiversity, with terrestrial ectotherms being particularly vulnerable. While climate-induced range shifts are often addressed in the literature, little is known about the underlying ecological responses at individual and population levels. Using a 30-year monitoring study of the long-living nocturnal gecko Gehyra variegata in arid Australia, we determined the relative contribution of climatic factors acting locally (temperature, rainfall) or distantly (La Nin᷉a induced flooding) on ecological processes ranging from traits at the individual level (body condition, body growth) to the demography at population level (survival, sexual maturity, population sizes). We also investigated whether thermoregulatory activity during both active (night) and resting (daytime) periods of the day can explain these responses. Gehyra variegata responded to local and distant climatic effects. Both high temperatures and high water availability enhanced individual and demographic parameters. Moreover, the impact of water availability was scale-independent as local rainfall and La Nin᷉a induced flooding compensated each other. When water availability was low, however, extremely high temperatures delayed body growth and sexual maturity while survival of individuals and population sizes remained stable. This suggests a trade-off with traits at the individual level that may potentially buffer the consequences of adverse climatic conditions at the population level. Moreover, hot temperatures did not impact nocturnal nor diurnal behavior. Instead, only cool temperatures induced diurnal thermoregulatory behavior with individuals moving to exposed hollow branches and even outside tree hollows for sun-basking during the day. Since diurnal behavioral thermoregulation likely induced costs on fitness, this could decrease performance at both individual and population level under cool temperatures. Our findings show that water availability rather than high temperature is the limiting factor in our focal population of G. variegata. In contrast to previous studies, we stress that drier rather than warmer conditions are expected to be detrimental for nocturnal desert reptiles. Identifying the actual limiting climatic factors at different scales and their functional interactions at different ecological levels is critical to be able to predict reliably future population dynamics and support conservation planning in arid ecosystems.

越来越多的证据表明，气候变化对生物多样性造成了显著影响，其中陆生变温动物（terrestrial ectotherms）尤其脆弱。现有研究多聚焦于气候驱动的物种分布范围迁移，但对个体与种群层面的潜在生态响应却知之甚少。本研究依托澳大利亚干旱区域针对长寿夜行性斑纹澳虎（Gehyra variegata）开展的长达30年的监测研究，剖析了局地气候因子（温度、降雨量）及远程气候因子（拉尼娜（La Niña）诱导的洪水事件）对一系列生态过程的相对贡献——这些过程涵盖个体层面的性状指标（身体状况、躯体生长）与种群层面的种群统计特征（存活率、性成熟时间、种群规模）。我们同时探究了动物在活动期（夜间）与休憩期（日间）的体温调节行为能否解释上述生态响应。斑纹澳虎对局地及远程气候因子均存在响应：高温与充足的水资源可利用性均可提升个体及种群统计参数。此外，水资源可利用性的影响不存在尺度依赖性，局地降雨与拉尼娜诱导的洪水可相互补偿。但当水资源可利用性匮乏时，极端高温会延缓躯体生长与性成熟进程，不过个体存活率与种群规模却保持稳定。这提示个体层面的性状存在权衡机制，或可缓冲不利气候条件对种群层面造成的负面影响。此外，高温并未对夜行或昼行行为产生显著影响；唯有低温会诱导昼行体温调节行为——个体日间会迁移至暴露的中空树枝，甚至离开树洞进行日光浴。由于昼行性体温调节可能会带来进化适合度（fitness）成本，因此在低温环境下，个体与种群层面的表现或会下降。本研究结果表明，在我们所聚焦的斑纹澳虎种群中，水资源可利用性而非高温才是限制性因子。与既往研究结论相悖，我们强调相较于气候变暖，干旱环境对夜行性沙漠爬行动物更为有害。精准识别不同尺度下的限制性气候因子及其在不同生态层级间的功能互作，对于可靠预测未来种群动态、支撑干旱生态系统的保护规划至关重要。