Biotic predictors complement models of bat and bird responses to climate and tree diversity in European forests

Bats and birds are key providers of ecosystem services in forests. How climate and habitat jointly shape their communities is well studied, but whether biotic predictors from other trophic levels may improve bird and bat diversity models is less known, especially across large bioclimatic gradients. Here, we achieved multi-taxa surveys in 209 mature forests replicated in six European countries from Spain to Finland, to investigate the importance of biotic predictors (i.e., the abundance or activity of defoliating insects, spiders, earthworms and wild ungulates) for bat and bird taxonomic and functional diversity. We found that 9 out of 12 bird and bat diversity metrics were best explained when biotic factors were added to models including climate and habitat variables, with a mean gain in explained variance of 38% for birds and 15% for bats. Tree functional diversity was the most important habitat predictor for birds, while bats responded more to understorey structure. The best biotic pr...蝙蝠与鸟类是森林生态系统服务的关键供给者。气候与栖息地如何共同塑造鸟类与蝙蝠群落的相关研究已较为充分，但来自其他营养级的生物预测因子能否优化鸟类与蝙蝠的多样性模型，这一问题仍有待厘清，尤其在大范围生物气候梯度下的情况更是如此。本研究在从西班牙至芬兰的六个欧洲国家中布设了209处成熟林样地并开展多类群调查，旨在探究生物预测因子（即食叶昆虫、蜘蛛、蚯蚓与野生有蹄类动物的丰度或活动水平）对蝙蝠与鸟类分类多样性及功能多样性的重要性。研究发现，在纳入气候与栖息地变量的模型中进一步加入生物因子后，12项鸟类与蝙蝠多样性指标中有9项的解释效果最优，鸟类的解释方差平均提升38%，蝙蝠则提升15%。对于鸟类而言，树木功能多样性是最重要的栖息地预测因子，而蝙蝠则对林下结构的响应更为显著。最佳生物预测因子……