Some like it hot: from individual to population responses of an arboreal arid-zone gecko to local and distant climate
Some like it hot: from individual to population responses of an arboreal arid-zone gecko to local and distant climate
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DOI：
10.1002/ecm.1301
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发表时间：
2018-08-01
影响因子：
6.1
通讯作者：
Henle, Klaus
中科院分区：
文献类型：
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作者：
Grimm-Seyfarth, Annegret;Mihoub, Jean-Baptiste;Henle, Klaus
越来越多的证据表明，气候变化对生物多样性产生了相当大的影响，其中陆地变温动物尤其脆弱。虽然文献中经常讨论气候引起的范围变化，但人们对个人和群体层面的潜在生态反应知之甚少。通过对澳大利亚干旱地区的长寿夜行性壁虎 Gehyra variegata 进行了 30 年的监测研究，我们确定了局部气候因素（温度、降雨）或远距离作用（拉尼娜引发的洪水）对生态过程的相对贡献，这些生态过程包括个体层面的特征（身体状况、身体生长）到种群层面的人口统计学（生存、性成熟、种群规模）。我们还研究了一天中活跃（夜间）和休息（白天）期间的体温调节活动是否可以解释这些反应。 Gehyra variegata 对当地和遥远的气候影响做出反应。高温和高可用水量都增强了个体和人口参数。此外，水资源供应的影响与规模无关，因为当地降雨和拉尼娜引发的洪水相互补偿。然而，当可用水量较低时，极高的温度会延迟身体生长和性成熟，而个体的存活率和种群规模却保持稳定。这表明在个体层面上进行权衡，可能会在人口层面上缓冲不利气候条件的后果。此外，高温不会影响夜间或白天的行为。相反，只有凉爽的温度才会引起昼夜温度调节行为，个体会在白天移动到暴露的空心树枝甚至树洞外晒太阳。由于昼夜行为体温调节可能会导致健康成本，这可能会降低个体和群体在低温下的表现。我们的研究结果表明，水的可用性而不是高温是我们的 G.variegata 重点种群的限制因素。与之前的研究相反，我们强调干燥而不是温暖的条件预计对夜间沙漠爬行动物有害。确定不同尺度的实际限制气候因素及其在不同生态水平的功能相互作用对于能够可靠地预测未来的人口动态并支持干旱生态系统的保护规划至关重要。
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-yr 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 Nina 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 Nina 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.