Microclimatic variables influence the temporal dynamics of an anuran metacommunity in a non-stationary way

Understanding the temporal dynamics of communities is crucial to elucidate how communities respond to climate change. The activities of ectothermic vertebrates are sensitive to climatic variations due to their sensibility to temperature and humidity. However, the factors that affect the temporal dynamics of communities of terrestrial ectothermic vertebrate remain poorly known. Here, we tested how microclimatic variables influence anuran species composition and if species abundances are stable through time in a metacommunity in the Atlantic Forest of southern Brazil. Using a multivariate method, called STATICO, we described the stable patterns and the spatio-temporal changes of the relationship between species composition and the microclimatic variables. We found that species turnover showed an asynchronous spatial pattern, while species composition exhibited a non-stationary response to climate, which was mainly related to temperature, rainfall, and humidity during the spring and summer. These results suggest storage effect as the main coexistence mechanism at play in the metacommunity, in which the asynchronous fluctuations promote species coexistence under a scenario of environmental variability.

理解群落的时间动态规律，对于阐明群落如何响应气候变化具有至关重要的意义。变温脊椎动物（ectothermic vertebrates）的活动极易受气候波动影响，因其对温度与湿度具有高度敏感性。然而，目前学界对影响陆地变温脊椎动物群落时间动态的驱动因子仍知之甚少。本研究以巴西南部大西洋森林中的两栖类集合群落（metacommunity）为研究对象，探究微气候变量如何影响无尾类（anuran）物种组成，并验证物种丰度是否随时间保持稳定。本研究采用名为STATICO的多元统计分析方法，刻画了物种组成与微气候变量之间关联的稳定模式及时空变化特征。研究结果显示，物种周转（species turnover）呈现异步空间格局，而物种组成对气候的响应表现为非平稳性，该响应主要与春季和夏季的气温、降水及湿度密切相关。上述结果表明，存储效应（storage effect）是该集合群落中发挥主导作用的物种共存机制，即在环境波动的背景下，异步种群波动可促进物种的稳定共存。