Hammill Edd, Dart Riley
Department of Watershed Sciences and the Ecology Center Utah State University Logan Utah 84341 USA.
Ecol Evol. 2022 Feb 22;12(2):e8665. doi: 10.1002/ece3.8665. eCollection 2022 Feb.
Future climate changes are predicted to not only increase global temperatures but also alter temporal variation in temperature. As thermal tolerances form an important component of a species' niche, changes to the temperature regime have the capacity to negatively impact species, and therefore, the diversity of the communities they inhabit. In this study, we used protist microcosms to assess how mean temperature, as well as temporal variation in temperature, affected diversity. Communities consisted of seven species in a multitrophic food web. Each ecosystem was inoculated with the same abundances of each species at the start of the experiment, and species densities, Hill's numbers (based on Shannon diversity), the number of extinctions, and the probability the microcosm contained predators were all calculated at the end of the experiment. To assess how mean temperature and temperature fluctuations affect stability, we also measured population densities through time. We found that increased temporal variation in temperature increased final densities, increased Hill's numbers (at low mean temperatures), decreased rates of extinctions, and increased the probability that predators survived till the end of the experiment. Mean temperatures did not significantly affect either the number of extinctions or the probability of predators, but did reduce the positive effect of increased temporal variation in temperature on overall diversity. Our results indicate that climatic changes have the potential to impact the composition of ecological communities by altering multiple components of temperature regimes. However, given that some climate forecasts are predicting increased mean temperatures and reduced variability, our finding that increased mean temperature and reduced temporal variation are both generally associated with negative consequences is somewhat concerning.
预计未来气候变化不仅会导致全球气温上升，还会改变温度的时间变化。由于热耐受性是物种生态位的重要组成部分，温度模式的变化有可能对物种产生负面影响，进而影响它们所栖息群落的多样性。在本研究中，我们使用原生生物微观世界来评估平均温度以及温度的时间变化如何影响多样性。群落由一个多营养级食物网中的七个物种组成。在实验开始时，每个生态系统接种相同数量的每个物种，并在实验结束时计算物种密度、希尔数（基于香农多样性）、灭绝数量以及微观世界中包含捕食者的概率。为了评估平均温度和温度波动如何影响稳定性，我们还随时间测量了种群密度。我们发现，温度时间变化的增加会提高最终密度、增加希尔数（在低平均温度下）、降低灭绝速率，并增加捕食者存活到实验结束的概率。平均温度对灭绝数量或捕食者的概率没有显著影响，但确实降低了温度时间变化增加对总体多样性的积极影响。我们的结果表明，气候变化有可能通过改变温度模式的多个组成部分来影响生态群落的组成。然而，鉴于一些气候预测预计平均温度会上升且变异性会降低，我们发现平均温度升高和时间变化减少通常都与负面后果相关，这有点令人担忧。
