Data from: Effects of experimental warming on biodiversity depend on ecosystem type and local species composition

Climatic warming is a primary driver of change in ecosystems worldwide. Here, we synthesize responses of species richness and evenness from 187 experimental warming studies in a quantitative meta-analysis. We asked 1) whether effects of warming on diversity were detectable and consistent across terrestrial, freshwater and marine ecosystems, 2) if effects on diversity correlated with intensity, duration, and experimental unit size of temperature change manipulations, and 3) whether these experimental effects on diversity interacted with ecosystem types. Using multilevel mixed linear models and model averaging, we also tested the relative importance of variables that described uncontrolled environmental variation and attributes of experimental units. Overall, experimental warming reduced richness across ecosystems (mean log-response ratio = –0.091, 95% bootstrapped CI: –0.13, –0.05) representing an 8.9% decline relative to ambient temperature treatments. Richness did not change in response to warming in freshwater systems, but was more strongly negative in terrestrial (–11.8%) and marine (–10.5%) experiments. In contrast, warming impacts on evenness were neutral overall and in aquatic systems, but weakly negative on land (7.6%). Intensity and duration of experimental warming did not explain variation in diversity responses, but negative effects on richness were stronger in smaller experimental units, particularly in marine systems. Model-averaged parameter estimation confirmed these main effects while accounting for variation in latitude, ambient temperature at the sites of manipulations, venue (field versus lab), community trophic type, and whether experiments were open or closed to colonization. These analyses synthesize extensive experimental evidence showing declines in local richness with increased temperature, particularly in terrestrial and marine communities. However, the more variable effects of warming on evenness were better explained by the random effect of site identity, suggesting that effects on species’ relative abundances were contingent on local species composition.

气候变暖是全球生态系统变化的核心驱动因子。本研究整合了187项实验增温研究中物种丰富度与均匀度的响应数据，开展定量元分析（meta-analysis）。我们旨在探讨三个核心科学问题：其一，增温对生物多样性的影响是否可被检测，且在陆地、淡水与海洋生态系统中具有一致性？其二，增温对多样性的影响是否与温度调控的强度、持续时长以及实验单元的大小相关？其三，这类增温对多样性的实验效应是否与生态系统类型存在交互作用？本研究采用多层混合线性模型（multilevel mixed linear models）与模型平均（model averaging）方法，同时检验了描述未受控环境变异与实验单元属性的各类变量的相对重要性。整体而言，实验增温降低了所有生态系统的物种丰富度（平均对数响应比（log-response ratio）为–0.091，95%自助法置信区间（bootstrapped CI）为–0.13至–0.05），相较于环境温度对照组，物种丰富度平均下降8.9%。淡水生态系统中，物种丰富度并未随增温发生显著变化，但陆地（–11.8%）与海洋（–10.5%）实验中的丰富度下降幅度更为显著。与之相对，增温对物种均匀度的整体影响以及在水生生态系统中的影响均呈中性，但在陆地生态系统中表现为弱负效应（降幅7.6%）。实验增温的强度与持续时长无法解释多样性响应的变异，但在较小的实验单元中，增温对丰富度的负效应更强，这一现象在海洋生态系统中尤为突出。经模型平均参数估计，在控制纬度、实验位点的环境温度、实验场所（野外 vs 实验室）、群落营养型（trophic type）以及实验是否开放拓殖（colonization）等变量的变异后，上述主效应得到了验证。本研究通过整合大量实验证据，证实随着温度升高，本地物种丰富度出现下降，在陆地与海洋群落中尤为显著。然而，增温对物种均匀度的影响更具变异性，这一效应可通过位点身份的随机效应得到更好的解释，这表明物种相对丰度的变化取决于当地的物种组成。