Abstract We studied the role of spatial (regional) and environmental (local) processes in the structuring of rodent metacommunities in three contiguous ecoregions that share the same species pool. The two northern ecoregions are mainly affected by anthropogenic processes (agriculture and urbanization) while the southern one is mainly affected by natural processes (flood and drought pulses). Local communities were described based on the analysis of 77 samples of barn owl pellets. To identify which processes (patch dynamics, species sorting, mass effect or neutral theory) structure each metacommunity we evaluated the percentage of variance explained by space (spatial arrangement of communities) and environment (topography, climate and land cover) in three Variation Partitioning Redundancy Analyses. The percentage of variance in rodent metacommunities composition explained by space and environment was between 38 and 61%, and was significant in all three analyses. The pure space fraction was significant for two of the three ecoregions, while the pure environmental fraction was significant for all three ecoregions. The processes that structure rodent metacommunities change across the region. In all three ecoregions the species sorting played a key role, while, mass effect was a structuring factor for northern metacommunities. These results can be explained by species-specific dispersal characteristics and environmental filtering.

中文翻译：

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空间和环境过程在啮齿动物元群落结构中作用的变化

摘要 我们研究了空间（区域）和环境（局部）过程在共享同一物种库的三个相邻生态区中啮齿动物元群落结构中的作用。北部的两个生态区主要受人为过程（农业和城市化）的影响，而南部的生态区主要受自然过程（洪水和干旱脉冲）的影响。根据对 77 个谷仓猫头鹰颗粒样品的分析描述了当地社区。为了确定哪些过程（补丁动态、物种分类、质量效应或中性理论）构成了每个元社区，我们评估了由空间（社区的空间排列）和环境（地形、气候和土地覆盖）在三个变异分区冗余中解释的方差百分比分析。空间和环境解释的啮齿动物元群落组成的变异百分比在 38% 到 61% 之间，并且在所有三项分析中都很显着。三个生态区中的两个的纯空间分数是显着的，而纯环境分数对于所有三个生态区都是显着的。构建啮齿动物元群落的过程在整个地区发生了变化。在所有三个生态区中，物种分类起着关键作用，而质量效应是北部元群落的结构因素。这些结果可以通过物种特定的扩散特征和环境过滤来解释。而纯环境部分对所有三个生态区都很重要。构建啮齿动物元群落的过程在整个地区发生了变化。在所有三个生态区中，物种分类起着关键作用，而质量效应是北部元群落的结构因素。这些结果可以通过物种特定的扩散特征和环境过滤来解释。而纯环境部分对所有三个生态区都很重要。构建啮齿动物元群落的过程在整个地区发生了变化。在所有三个生态区中，物种分类起着关键作用，而质量效应是北部元群落的结构因素。这些结果可以通过物种特定的扩散特征和环境过滤来解释。