The role of the thermal niche in past warming worlds (ThermNiche)

了解过去和现在的生态系统的动态和预测响应气候变化的方向变化是（古）生态学长期面临的挑战。我们建议应用热生态位的概念来研究气候变暖对物种纬向分布和动物群热结构变化的影响。利用海洋底栖大型无脊椎动物的发生数据和来自氧同位素和气候模拟的海水温度图，我们详细讨论了在Pliensbachian-Toarcian（早侏罗世）时间间隔内气候唐斯的影响，并随后将我们的分析扩展到中生代。首先，我们测试是否变暖正在缩小物种的纬度范围（假设1），同时假设变暖优先导致物种向极地转移。其次，我们认为，组合的热结构决定其对变暖的反应（假设2）。特别是我们假设，移民有温暖的实现热生态位比预先存在的组合平均值，灭绝盛行的物种之间的温度升高超过其上限的热限制，并增加或减少的物种的丰度预测各自预先存在的热生态位。第三，我们探讨了动物群的组成和热结构的变化是最明显的热带和温带物种的暖缘积累分别（假设3）。在这种情况下，我们预测，当地的人口损失优先发生在组合的比例高的最温暖的亲和力的物种，而移民是可以忽略不计的;第二个最大的人口损失是位于赤道分布边缘的温带物种，这暖温带地区也收到显着的移民热带物种的组合内的动物区系营业额的高峰。了解了热生态位的作用，我们期望能够提供关于海洋生态系统在多大程度上保持凝聚力或发生变化的知识，包括在气候变化面前，移民或新进化的物种取代现有物种。

Understanding the dynamics of past and present ecosystems and predicting directional changes in response to climate change are long-standing challenges in (paleo-)ecology. We propose to apply the concept of the thermal niche to study the effects of climate warming on shifts in the latitudinal distribution of species and in the thermal structure of faunal assemblages. Using occurrence data of marine benthic macroinvertebrates and maps of seawater temperatures derived from oxygen isotopes and climate modelling, we address in detail the effects of climatic ups and downs during the Pliensbachian-Toarcian (Early Jurassic) time interval, and subsequently extend our analyses to the Phanerozoic eon. First, we test whether warming is narrowing the latitudinal ranges of species (hypothesis 1) alongside the hypothesis that warming preferentially results in poleward shifts of species. Second, we argue that the thermal structure of an assemblage determines its response to warming (hypothesis 2). Particularly we hypothesize that immigrants have warmer realized thermal niches than the pre-existing assemblage average; that extirpation prevails among species for which raised temperatures exceed their upper thermal limits; and that increase or decrease in the abundance of species is predicted by their respective pre-existing thermal niche. Third, we explore whether changes in the composition and thermal structure of faunal assemblages are most distinct at the warm edge accumulations of tropical and temperate species respectively (hypothesis 3). In this context, we predict that local population losses occurred preferentially in assemblages with high proportions of the warmest-affinity species, whereas immigrations are negligible; that a second maximum of population losses is located at the equatorward distribution edge of temperate species; and that this warm temperate zone also receives significant immigrations of tropical species resulting in peaks of faunal turnover within assemblages. Understanding the role of the thermal niche, we expect to contribute knowledge about the extent to which marine ecosystems remain cohesive or are transformed, involving replacements of incumbent species by immigrants or newly evolved species, in the face of climate change.