Data from: Ecophysiological variation across a forest-ecotone gradient produces divergent climate change vulnerability within species

Climate change related risks and impacts on ectotherms will be mediated by habitats and their influence on local thermal environments. While many studies have documented morphological and genetic aspects of niche divergence across habitats, few have examined thermal performance across such gradients and directly linked this variation to contemporary climate change impacts. In this study, we quantified variation in thermal performance across a gradient from forest to gallery forest-savanna mosaic in Cameroon for a skink species (Trachylepis affinis) known to be diverging genetically and morphologically across that habitat gradient. Based on these results, we then applied a mechanistic modelling approach (NicheMapR) to project changes in potential activity, as constrained by thermal performance, in response to climate change. As a complimentary approach, we also compared mechanistic projections with climate-driven changes in habitat suitability based on species distribution models of forest and ecotone skinks. We found that ecotone skinks may benefit from warming and experience increased activity while forest skinks will likely face a drastic decrease in thermal suitability across the forest zone. Species distribution models projected that thermal suitability for forest skinks in coastal forests would decline but in other parts of the forest zone skinks are projected to experience increased thermal suitability. The results here highlight the utility of mechanistic approaches in revealing and understanding patterns of climate change vulnerability which may not be detected with species distribution models alone. This study also emphasizes the importance of intra-specific physiological variation, and habitat-specific thermal performance relationships in particular, in determining warming responses.

气候变化相关风险及其对变温动物（ectotherms）的影响，将通过生境及其对局地热环境的调控作用得以塑造。尽管诸多研究已针对生境间的生态位分化开展了形态学与遗传学维度的记载，但鲜有研究探究此类梯度下的热表现，并将该变异直接与当代气候变化影响建立关联。本研究以喀麦隆境内沿森林-河岸林稀树草原镶嵌体梯度分布的石龙子物种（Trachylepis affinis）为研究对象，该物种已知在该生境梯度下存在遗传与形态分化，我们量化了其热表现沿该梯度的变异情况。基于上述结果，我们采用机制建模方法（NicheMapR），以热表现为约束条件，预测了气候变化背景下物种潜在活动的变化。作为补充研究手段，我们还基于森林与生态交错带石龙子的物种分布模型，将机制模型预测结果与气候变化驱动的生境适宜性变化进行了对比。研究结果显示，生态交错带石龙子或可从气候变暖中获益，活动时长将有所增加；而森林带内的石龙子则可能面临热适宜性在整个森林区域内的大幅下降。物种分布模型预测显示，沿海森林内的森林石龙子热适宜性会有所降低，但森林区域其他部分的石龙子热适宜性则预计会上升。本研究结果凸显了机制模型方法的应用价值：其可揭示并阐释仅通过物种分布模型无法捕捉到的气候变化脆弱性模式。本研究同时强调，在预测物种对气候变暖的响应时，种内生理变异，尤其是生境特异性的热表现关系，具有重要意义。