Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada.
School of the Environment, University of Toronto, Toronto, ON, Canada.
Glob Chang Biol. 2022 Mar;28(5):1725-1739. doi: 10.1111/gcb.15766. Epub 2021 Sep 20.
Temperate ectotherms have responded to recent environmental change, likely due to the direct and indirect effects of temperature on key life cycle events. Yet, a substantial number of ectotherms are fossorial, spending the vast majority of their lives in subterranean microhabitats that are assumed to be buffered against environmental change. Here, we examine whether seasonal climatic conditions influence body condition (a measure of general health and vigor), reproductive output, and breeding phenology in a northern population of fossorial salamander (Spotted Salamander, Ambystoma maculatum). We found that breeding body condition declined over a 12-year monitoring period (2008-2019) with warmer summer and autumn temperatures at least partly responsible for the observed decline in body condition. Our findings are consistent with the hypothesis that elevated metabolism drives the negative association between temperature and condition. Population-level reproduction, assessed via egg mass counts, showed high interannual variation and was weakly influenced by autumn temperatures. Salamander breeding phenology was strongly correlated with lake ice melt but showed no long-term temporal trend (1986-2019). Climatic warming in the region, which has been and is forecasted to be strongest in the summer and autumn, is predicted to lead to a 5%-27% decline in salamander body condition under realistic near-future climate scenarios. Although the subterranean environment offers a thermal buffer, the observed decline in condition and relatively strong effect of summer temperature on body condition suggest that fossorial salamanders are sensitive to the effects of a warming climate. Given the diversity of fossorial taxa, heightened attention to the vulnerability of subterranean microhabitat refugia and their inhabitants is warranted amid global climatic change.
温带变温动物对最近的环境变化做出了反应，这可能是由于温度对关键生命周期事件的直接和间接影响。然而，大量的变温动物是穴居的，它们一生中的绝大部分时间都生活在地下微生境中，这些微生境被认为可以免受环境变化的影响。在这里，我们研究了季节性气候条件是否会影响穴居蝾螈（斑点蝾螈，Ambystoma maculatum）的北方种群的身体状况（衡量一般健康和活力的指标）、繁殖产量和繁殖物候。我们发现，在 12 年的监测期间（2008-2019 年），繁殖体况下降，夏季和秋季温度升高至少部分导致了体况的下降。我们的研究结果与这样的假设一致，即新陈代谢率的升高导致了温度与身体状况之间的负相关。通过卵质量计数评估的种群水平繁殖显示出高度的年际变化，并且受秋季温度的影响较弱。蝾螈的繁殖物候与湖泊冰融化强烈相关，但没有长期的时间趋势（1986-2019 年）。该地区的气候变暖已经并且预计在夏季和秋季最为强烈，根据现实的近未来气候情景预测，这将导致蝾螈身体状况下降 5%-27%。尽管地下环境提供了热缓冲，但观察到的状况下降和夏季温度对身体状况的相对强烈影响表明，穴居蝾螈对气候变暖的影响很敏感。鉴于穴居动物类群的多样性，在全球气候变化中，需要更加关注地下微生境避难所及其居民的脆弱性。
