To better understand the consequences of global warming for species and their distribution, we need studies quantifying how environmental change affects communities and interaction networks. Where studies to date have mainly focused on climatic effects on species distribution (the Grinnellian dimension of the niche), recent research has emphasised how the environment shapes ecological interactions among species (the Eltonian dimension).

Here, we explore both dimensions in a system consisting of two wolf spider species – Pardosa palustris and Pirata piraticus – and their prey. Drawing on a natural experiment consisting of differential geothermal heating of soil, we describe the effects of temperature on the abundance of each species and on its interactions with its prey (using metabarcoding of gut contents). The two spider species differed substantially in their Grinnellian niche, with a peak in the abundance of P. palustris around 10 °C and in P. piraticus around 22 °C. While P. piraticus consumed more prey taxa on average than did P. palustris, both predators maintained their diet breadth and taxon richness of consumed prey across the temperature gradient. This indicates that effects of temperature on metabolic demands did not alter the dietary specialisation of the two predators. Nevertheless, we did also detect effects of temperature on the Eltonian niche, with significant changes in the prey community consumed by the two spider species across the temperature gradient, and a greater turnover of prey taxa in their diet with increasing soil temperature. Importantly, this suggests that the Eltonian niche of species may be conditional on the environment, and that prey use by generalist predators may thus be modified by climate change.

为了更好地了解全球变暖对物种及其分布的影响，我们需要进行量化环境变化如何影响社区和相互作用网络的研究。迄今为止，研究主要集中在气候对物种分布的影响（利基的格林尼利尺度）上，而最近的研究则强调了环境如何影响物种之间的生态相互作用（埃尔顿尺度）。

在这里，我们探索由两个狼蛛物种-Pardosa palustris和Pirata piraticus-以及它们的猎物组成的系统中的两个维度。借助由土壤的不同地热加热组成的自然实验，我们描述了温度对每种物种的丰度及其与猎物的相互作用的影响（使用肠内容物的超条形码）。这两种蜘蛛物种的格林尼利生态位差异很大，在10°C左右的P. palustris和在22°C附近的P. piraticus的丰度峰值。虽然Piraticus比P. palustris平均消耗更多的猎物类群，这两个食肉动物在整个温度梯度上都维持着所吃猎物的饮食宽度和分类单元丰富性。这表明温度对新陈代谢需求的影响并未改变两个捕食者的饮食专长。尽管如此，我们也确实检测到了温度对Eltonian生态位的影响，这两个蜘蛛物种在温度梯度范围内消耗的猎物群落发生了显着变化，并且随着土壤温度的升高，其饮食中捕食类群的营业额增加。重要的是，这表明埃尔顿物种的生态位可能取决于环境，因此通俗捕食者对猎物的使用可能会因气候变化而改变。