Data from: Phylogenetic community structure of North American desert bats: influence of environment at multiple spatial and taxonomic scales

1. Numerous processes influence community structure. The relative importance of these processes are thought to vary with spatial, temporal, and taxonomic scale: density dependent interactions are thought to be most influential 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 favorable conditions will be structured predominantly by density dependent interactions such as competition. 2. 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 if the stress-dominance hypothesis is upheld in desert bats across an environmental gradient. 3. PCS 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) scale. We calculated mean temperature, precipitation, and seasonality for each site to determine if environmental gradients were related to degree of community structure. 4. 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. 5. 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.

1. 诸多生态过程共同调控群落结构。学界普遍认为，这些过程的相对重要性随空间、时间及分类学尺度的变化而存在差异：密度依赖相互作用在小尺度下的影响最为显著，中等尺度下环境条件或为最关键的驱动因子，而大尺度下则以生物地理过程的作用更为突出。此外，压力优势假说（stress-dominance hypothesis）提出：环境条件严苛的群落，其结构主要由生境过滤（habitat filtering）主导；而环境条件更优越的群落，则主要受竞争等密度依赖相互作用调控。
2. 本研究旨在探究多空间与分类学尺度下，环境因子对北美荒漠蝙蝠系统发育群落结构（phylogenetic community structure, PCS）的影响，并验证压力优势假说在环境梯度下的荒漠蝙蝠群落中是否成立。
3. 本研究以不同空间尺度（涵盖全荒漠区域至单个荒漠）与分类学尺度（涵盖所有蝙蝠类群、单科蝙蝠以及单属蝙蝠）的物种库为基础，计算了系统发育群落结构相关指标。同时，我们为每个样地计算了年均温、降水量与温度季节性等环境参数，以明确环境梯度与群落结构发育程度之间的关联。
4. 在最大的空间与分类学尺度下，群落呈现出显著的系统发育聚集特征；而在最小的空间与分类学尺度下，聚集程度则显著降低。在大尺度与严苛环境条件下，气候数据（尤其是年均温与温度季节性）是系统发育群落结构的重要预测因子；但在小尺度与环境较优越的条件下，系统发育群落结构与气候的关联则相对较弱。
5. 该结果表明，北美荒漠虽环境严苛，但其对栖息于此的动物群落构成的挑战并不统一。综合来看，大空间与分类学尺度以及严苛环境条件下系统发育群落结构与气候数据的关联，说明生境过滤在北美荒漠蝙蝠群落的组装过程中发挥了重要作用；而小尺度下则以其他生态过程的调控更为关键。