Abstract

Seasonality exerts strong pressures on biodiversity patterns. Yet, temporal beta-diversity is poorly studied in tropical systems, and the drivers of variability in amphibian activity and seasonality remain largely unknown. We quantified intra- and interannual variation in temporal beta-diversity relying on a nine-year, year-round survey (51 species, n > 23,000) performed in a protected area (Betampona, Madagascar). We assessed the dependence on climate of beta-diversity and abundance using a distance-based redundancy analysis and generalised linear mixed models, respectively. Despite the majority of species being preferentially active during one specific period, beta-diversity and abundance were more variable between years than within years. Temporal variation in beta-diversity was best explained by temperature (but climate accounted for only 2% of variation). Species abundance was best explained by temperature (for 32% of the tested species), monthly humidity (30%) and monthly rainfall (24%). We found no climatic dependence for 24% of the species. Our results suggest that studies focusing on species phenology can be misleading when based on single-year surveys even in seasonal systems. The high interannual variability in diversity may be due to an adaptive responses to an important regime of stochastic events. Given the direction of the relationships between weather and abundances, we predict that a large proportion of amphibians would suffer from climate change in Madagascar. We emphasise the need to account for multiple temporal scales in studies of tropical species composition and abundance to better understand species phenology and their response to climate change, and make targeted conservation actions more effective.

中文翻译：

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气候驱动的两栖动物群落在季节性雨林中的高年际变化

摘要

季节性对生物多样性格局施加了巨大压力。然而，在热带系统中对时间β多样性的研究很少，并且两栖动物活动和季节性变化的动因很大程度上仍然未知。我们通过在保护区（马达加斯加的贝坦波纳）进行的为期9年的全年调查（51种，n> 23,000）对量化的时间内β多样性的年内和年际变化进行了量化。我们分别使用基于距离的冗余分析和广义线性混合模型，评估了对β多样性和丰度气候的依赖性。尽管大多数物种在一个特定时期内优先活动，但β多样性和丰度在几年之间比几年内变化更大。β多样性的时间变化最好用温度来解释（但气候仅占变化的2％）。最好用温度（占测试物种的32％），每月湿度（30％）和每月降雨量（24％）来解释物种的丰富度。我们发现24％的物种没有气候依赖性。我们的结果表明，即使是在季节性系统中，基于单年调查，针对物种物候学的研究也会产生误导。多样性的高年际变化可能是由于对随机事件的重要机制的适应性响应。考虑到天气和丰度之间关系的方向，我们预测马达加斯加的两栖动物将遭受气候变化的影响。