Species distributions and the mechanisms that produce patterns in the occupation space are recurrent themes in community ecology. Here, we examine beta diversity among assemblages of small mammals in the Cerrado domain of Brazil to partition the effects of turnover and nestedness on species distributions. Our objective was to evaluate whether balanced spatial variation in abundance (β _bal) and abundance gradients (β _gra) are congruent within and among habitats and localities of the Brazilian Cerrado. In addition, we wanted to understand whether ecological mechanisms, such as dispersal limitation, habitat filtering, and species sorting, drive the distribution patterns of the Cerrado small mammals. We analyzed the occurrence and abundances of small mammals from 16 localities widely distributed across the Cerrado biome, and grouped our data with respect to two distinct spatial scales. Baselga’s Bray–Curtis index of dissimilarity and its respective partitions, i.e., balanced variation in abundance (β _bal) and abundance gradients (β _gra), were estimated between sampling units at the two spatial scales. Thus, we used exponential models to search for distance decay in species similarity between pairs of localities and between similar habitats. Our results show that differences between small mammal assemblages in the Cerrado are driven mainly by species replacement rather than independent gain or loss of species, both at small and large scales. The spatial turnover patterns of small mammals in the Cerrado biome are determined by a combination of large scale (biogeographic, spatial) and local mechanisms (low dispersal and habitat specificity). However, processes occurring at small scales seem to be more important in species sorting than processes occurring at large scales. The spatial configuration of the landscape and the extent and quality of habitats strongly influence the rate of species turnover in Cerrado. Thus, protecting the different types of habitats should be of prime importance to conserving the diversity of Cerrado small mammals.

中文翻译：

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划分beta多样性，以揭示巴西塞拉多（Cerrado）非挥发性小哺乳动物分布的基础机制

物种分布和在占用空间中产生模式的机制是社区生态学中经常出现的主题。在这里，我们检查了巴西塞拉多地区小型哺乳动物种群中的β多样性，以划分营业额和嵌套对物种分布的影响。我们的目的是评估丰度（  _βbal）和丰度梯度（  _βgra）与巴西Cerrado的栖息地和地区内部和之中完全一致。此外，我们想了解生态机制（例如扩散限制，栖息地过滤和物种分类）是否驱动了塞拉多小型哺乳动物的分布方式。我们分析了Cerrado生物群落中分布广泛的16个地区的小型哺乳动物的发生和丰富程度，并针对两个不同的空间尺度对数据进行了分组。巴塞尔加的Bray-Curtis相似度指数及其各自的分区，即丰度（  _βbal）和丰度梯度（  _βgra）是在两个空间尺度上的采样单位之间估算的。因此，我们使用指数模型来搜索成对的地点之间以及相似的栖息地之间物种相似度的距离衰减。我们的研究结果表明，塞拉多小型哺乳动物种群之间的差异主要是由物种替代驱动的，而不是由小规模或大规模的物种独立获得或失去的。塞拉多生物群系中小型哺乳动物的空间更新模式是由大规模（生物地理，空间）和局部机制（低扩散和生境特异性）共同决定的。但是，小规模发生的过程似乎比大范围发生的过程在物种分类中更为重要。景观的空间配置以及生境的范围和质量强烈影响塞拉多物种周转率。因此，保护​​不同类型的栖息地对于保护塞拉多小型哺乳动物的多样性至关重要。