Tradition vs. innovation: comparing bioacoustics and mist-net results to bat sampling

Bats are a complex and diverse group, making their study remarkably challenging. Several methods allow the study of bats, e.g. mist-nets and acoustic monitoring (AM). We compare the use of AM and mist-nets to inventory bats in a mountainous region of São Paulo state, Brazil. We provide a species list for the study area based on species registered with both methodologies, comparing with a species list known for the state, obtained from the literature. We calculated beta diversity between methodologies to evaluate the dissimilarity in species composition sampled with these methods. We also performed a PCA to evaluate if the bat fauna sampled with AM showed species-habitat associations. We recorded 15 species/sonotypes through AM and 22 species through mist-nets. Beta diversity revealed 97% of dissimilarity in species composition. The turnover component explained 96% of this dissimilarity. PCA revealed that Vespertilionidae bats were associated with border/cluttered habitats, while Molossidae bats were present in all habitat types. The species list for the state comprises eighty species. Our inventory recorded more than 25% of this fauna. Mist-nets are efficient for sampling low-flying/low-intensity echolocating bats. AM is crucial for sampling high-flying/high-intensity echolocating bats. This is the second study to use AM to inventory bats in this state.

蝙蝠是一类复杂多样的类群，其相关研究极具挑战性。目前可用于蝙蝠研究的方法包括雾网(mist-net)与声学监测(acoustic monitoring, AM)。本研究针对巴西圣保罗州某山区开展蝙蝠类群调查，对比了雾网与声学监测两种方法的应用效果；基于两种方法记录的物种编制了研究区域的蝙蝠物种名录，并与文献中记载的该州已知蝙蝠物种名录进行对比；通过计算两种方法间的β多样性(beta diversity)，评估其采样得到的物种组成差异；此外还开展了主成分分析(Principal Component Analysis, PCA)，以探究声学监测采样得到的蝙蝠类群是否存在物种-生境关联。本研究中，声学监测共记录到15个物种/声波型(sonotype)，雾网则记录到22个物种；β多样性分析显示，两种方法的物种组成差异度达97%，其中物种更替组分解释了该差异的96%；主成分分析结果显示，蝙蝠科(Vespertilionidae)蝙蝠与林缘/复杂生境存在关联，而犬吻蝠科(Molossidae)蝙蝠则在各类生境中均有分布。该州已知的蝙蝠物种名录共计80种，本研究的调查结果覆盖了该州蝙蝠区系的25%以上。雾网对采样低飞行、低回声定位强度的蝙蝠群体效率更高，而声学监测则是采样高飞行、高回声定位强度蝙蝠群体的关键手段，本研究是该州第二项采用声学监测开展蝙蝠调查的研究。