Data from: Following the water? landscape-scale temporal changes in bat spatial distribution in relation to Mediterranean summer drought

Understanding how the spatial distribution of ecological resources shape species’ diversity and abundance in human-modified landscapes is a central theme in conservation biology. However, studies often disregard that such patterns may vary over time, thereby potentially missing critical environmental constraints to species persistence. This may be particularly important in highly mobile species such as bats, which are able to track temporal variations in spatial resource distribution. Here we test the hypothesis that bats in Mediterranean landscapes are strongly affected by the progressive reduction in water availability during the seasonal summer drought. We analysed the effects of landscape composition and structure on bat diversity and activity, during Pregnancy, Lactation and Post-lactation periods, and identified the most influential variables within and across periods. Water bodies showed the strongest positive effect on bats, followed by riparian habitats and areas with steeper (>30%) slopes. However, while during Pregnancy there were only small landscape effects, these increased during Lactation and Post-lactation, highlighting a progressively stronger association with water habitats during the summer drought. The spatial projection of habitat models showed that the landscape distribution of bat diversity and activity hotspots changed markedly over time. During Pregnancy the spatial pattern of hotspot distribution was weakly defined, while during Lactation and particularly Post-lactation there was a concentration of hotspots along permanently flowing watercourses. Our study highlights that permanently flowing watercourses are critical for bat conservation in Mediterranean landscapes, calling for measures to counteract their ongoing degradation due in particular to climate change, water abstraction and damming. More generally, our study underlines the importance of considering the temporal dimension in habitat selection studies, without which there is the risk of overlooking the importance of habitats that are key for species persistence only at certain times of the year.解析人类改造景观中生态资源的空间分布如何塑造物种多样性与种群丰度，是保护生物学的核心研究议题之一。然而，现有研究往往忽视此类格局会随时间动态变化，从而可能遗漏维持物种存续的关键环境限制因子。对于蝙蝠这类能够追踪空间资源分布时间动态的高度移动性物种而言，这一点尤为关键。本研究针对地中海型景观中的蝙蝠展开假说验证：即蝙蝠的生存会受到季节性夏季干旱期间可利用水资源逐步减少的显著影响。本研究分析了景观组成与结构对蝙蝠多样性及活动强度在妊娠、泌乳及泌乳后期三个阶段的影响，并识别了各阶段内以及跨阶段的关键影响变量。水体对蝙蝠展现出最强的正向促进效应，其次是河岸生境与坡度超过30%的区域。不过，尽管妊娠阶段仅存在微弱的景观效应，但该效应在泌乳阶段与泌乳后期均显著增强，凸显出夏季干旱期间蝙蝠与水生境的关联程度逐步提升。生境模型的空间投影结果显示，蝙蝠多样性与活动热点的景观分布随时间发生显著变化。妊娠阶段的热点分布空间格局较为模糊，而泌乳阶段，尤其是泌乳后期，热点区域集中分布于常年流动的河道沿线。本研究凸显出常年流动的河道对于地中海型景观中的蝙蝠保护至关重要，呼吁采取措施抵消其因气候变化、水资源抽取与筑坝等因素持续退化的现状。从更广泛的层面而言，本研究强调在生境选择研究中纳入时间维度的重要性——若缺乏该维度，便可能忽视仅在一年中特定时段对物种存续至关重要的生境的价值。