Data from: Thermal sensitivity of a neotropical amphibian (Engystomops pustulosus) and its vulnerability to climate change

A species’ thermal sensitivity and its exposure to climate
variation are key components in the prediction of its vulnerability to climate change. We tested the thermal sensitivity of a tropical amphibian that lives in a mild constant climate in which the thermal tolerance range is expected to closely match the experienced environmental temperature. The air temperature that this species is exposed to varies between 21.9-31.6ºC
with an annual mean of 27.2ºC. We estimated the microhabitat water temperature variation under vegetation shade, which buffers the temperature by 1.8ºC in relation to that of the air, and with open canopy, where the water was 1.9ºC warmer than the air temperature. With broods of tadpoles split into five treatments (15ºC, 21ºC, 28ºC, 31ºC, and 33ºC) we estimated the critical thermal maximum (CTMax) and critical thermal minimum
(CTMin) after at least 7 days of acclimation. Both CTMax (42.3ºC) and CTMin (11.8ºC) were more extreme than the temperature range estimated for the field. We estimated the optimum temperature (To = 28.8ºC) and the thermal performance breadth (range: 23.3-34.1ºC) based on growth rate (g/day). The animals were able to acclimate more extensively to cold than to warm temperatures. These performance curve traits closely matched the air temperature. The estimated vulnerability varied according to the microhabitat prediction model used. The combination of tadpole data on thermal sensitivity and macro- microhabitat variation provides a necessary framework to
understand the effects of climate change on tropical amphibians.

物种的热敏感性及其所处的气候变异暴露水平，是预测其气候变化脆弱性的核心要素。本研究针对一种栖息于温和恒定气候环境的热带两栖动物开展热敏感性测试，该物种的热耐受范围理论上应与其日常经历的环境温度高度匹配。该物种所处的环境气温区间为21.9~31.6℃，年平均气温为27.2℃。我们分别评估了两类微生境下的水体温度变化：其一为植被遮阴区域，其水体温度较空气温度低1.8℃，可起到温度缓冲作用；其二为开阔冠层区域，其水体温度较空气温度高1.9℃。我们将多窝蝌蚪分为5组驯化处理组（15℃、21℃、28℃、31℃及33℃），在至少7天的温度驯化后，分别测定了其临界热最大值（Critical Thermal Maximum, CTMax）与临界热最小值（Critical Thermal Minimum, CTMin）。测定结果显示，CTMax为42.3℃、CTMin为11.8℃，二者均较野外实测温度区间更为极端。我们基于蝌蚪的日生长速率（g/天），估算得到其最适温度（Optimum Temperature, To）为28.8℃，热性能广度区间为23.3~34.1℃。相较于高温驯化，该物种对低温环境的驯化能力更强。上述热性能曲线特征与该物种所处的空气温度高度匹配。其气候变化脆弱性的估算结果会因所采用的微生境预测模型不同而存在差异。将蝌蚪的热敏感性数据与宏生境、微生境的变异特征相结合，可为理解气候变化对热带两栖动物的影响提供必要的研究框架。