Patrick Lorelei E, Stevens Richard D
Department of Biological Sciences, Louisiana State University, 202 Life Sciences Building, Baton Rouge, LA, 70803, USA.
Department of Natural Resources Management, Museum of Texas Tech University, 007D Goddard Hall, Lubbock, TX, 79409, USA.
J Anim Ecol. 2016 Jul;85(4):1118-30. doi: 10.1111/1365-2656.12529. Epub 2016 May 16.
Numerous processes influence community structure. The relative importance of these processes is thought to vary with spatial, temporal and taxonomic scales: density-dependent interactions are thought to be most important at small scales; at intermediate scales, environmental conditions may be the most influential factor; and biogeographic processes are thought to be of greater importance at larger scales. Additionally, the stress-dominance hypothesis suggests that communities experiencing harsher environmental conditions will be predominantly structured by habitat filtering, whereas communities experiencing more favourable conditions will be structured predominantly by density-dependent interactions such as competition. The aim of this study was to investigate the influence of environmental factors on phylogenetic community structure (PCS) of North American desert bats at multiple spatial and taxonomic scales. We also examined whether the stress-dominance hypothesis is upheld in desert bats across an environmental gradient. Phylogenetic community structure metrics were calculated using species pools that differed in spatial (from all deserts to individual deserts) and taxonomic (all bat taxa, a single family and a single genus) scales. We calculated mean temperature, precipitation and seasonality for each site to determine whether environmental gradients were related to degree of community structure. At the largest spatial and taxonomic scales, communities were significantly phylogenetically clustered while degree of clustering decreased at the smallest spatial and taxonomic scales. Climatic data, particularly mean temperature and temperature seasonality, were important predictors of PCS at larger scales and under harsher conditions, but at smaller scales and in less stressful conditions there was a weaker relationship between PCS and climate. This suggests that North American deserts, while harsh, are not uniform in the challenges they present to the faunas residing in them. Overall, the relationship between PCS and climatic data at large spatial and taxonomic scales, and in harsher conditions, suggests the influence of habitat filtering has been important in North American desert bat community assembly and that other processes have been important at smaller scales.
众多过程影响群落结构。这些过程的相对重要性被认为会随空间、时间和分类尺度而变化：密度依赖的相互作用在小尺度上被认为最为重要；在中等尺度上，环境条件可能是最具影响力的因素；而生物地理过程在大尺度上被认为更为重要。此外，胁迫主导假说表明，经历更恶劣环境条件的群落将主要由生境过滤构建结构，而经历更有利条件的群落将主要由密度依赖的相互作用（如竞争）构建结构。本研究的目的是在多个空间和分类尺度上调查环境因素对北美沙漠蝙蝠系统发育群落结构（PCS）的影响。我们还检验了胁迫主导假说在整个环境梯度上的沙漠蝙蝠中是否成立。使用在空间（从所有沙漠到单个沙漠）和分类（所有蝙蝠类群、单个科和单个属）尺度上不同的物种库计算系统发育群落结构指标。我们计算了每个地点的平均温度、降水量和季节性，以确定环境梯度是否与群落结构程度相关。在最大的空间和分类尺度上，群落显著地在系统发育上聚类，而在最小的空间和分类尺度上聚类程度降低。气候数据，特别是平均温度和温度季节性，在较大尺度和更恶劣条件下是PCS的重要预测因子，但在较小尺度和压力较小的条件下，PCS与气候之间的关系较弱。这表明北美沙漠虽然恶劣，但它们对栖息其中的动物群所带来的挑战并非千篇一律。总体而言，在大空间和分类尺度以及更恶劣条件下，PCS与气候数据之间的关系表明生境过滤的影响在北美沙漠蝙蝠群落组装中很重要，而其他过程在较小尺度上也很重要。
