Pós-Graduação em Ecologia, Instituto Nacional de Pesquisas da Amazônia, Manaus, Amazonas, Brasil.
Pós-Graduação em Recursos Naturais Amazônicos, Universidade Federal do Oeste do Pará, Santarém, Pará, Brasil.
PLoS One. 2020 Jun 2;15(6):e0233881. doi: 10.1371/journal.pone.0233881. eCollection 2020.
Investigating the role of historical and ecological factors structuring assemblages is relevant to understand mechanisms and processes affecting biodiversity across heterogeneous habitats. Considering that community assembly often involves scale-dependent processes, different spatial scales may reveal distinct factors structuring assemblages. In this study we use arboreal and leaf-litter lizard abundance data from 83 plots to investigate assemblage spatial structure at two distinct scales in southwestern Brazilian Amazonia. At a regional scale, we test the general hypothesis that the Madeira River acts as a barrier to dispersal of some lizard species, which results in distinct assemblages between river banks. At a local scale, we test the hypothesis that assemblages are not evenly distributed across heterogeneous habitats but respond to a continuum of inadequate-to-optimal portions of environmental predictors. Our results show that regional lizard assemblages are structured by the upper Madeira River acting as a regional barrier to 29.62% of the species sampled. This finding suggests species have been historically isolated at one of the river banks, or that distinct geomorphological features influence species occurrence at each river bank. At a local scale, different sets of environmental predictors affected assemblage composition between river banks or even along a river bank. These findings indicate that environmental filtering is a major cause of lizard assemblage spatial structure in the upper Madeira River, but predictor variables cannot be generalized over the extensive (nearly 500 km) study area. Based on a single study system we demonstrate that lizard assemblages along the forests near the banks of the upper Madeira River are not randomly structured but respond to multiple factors acting at different and hierarchical spatial scales.
研究历史和生态因素对生物群落结构的作用对于理解影响异质生境中生物多样性的机制和过程至关重要。考虑到群落组装通常涉及尺度依赖的过程，不同的空间尺度可能会揭示出不同的结构组装因素。在这项研究中，我们使用来自巴西亚马逊西南部 83 个样地的树栖和叶层蜥蜴丰度数据，在两个不同的空间尺度上研究了群落的空间结构。在区域尺度上，我们检验了一个普遍假设，即马德拉河作为一些蜥蜴物种扩散的屏障，导致河岸两侧的群落明显不同。在局部尺度上，我们检验了这样一个假设，即群落不是均匀分布在异质生境中，而是对环境预测因子的不充分到最佳部分的连续体做出响应。我们的研究结果表明，区域蜥蜴群落结构是由作为区域屏障的上马德拉河作用于 29.62%的采样物种来决定的。这一发现表明，物种在河岸的某一侧已经经历了历史隔离，或者不同的地貌特征影响了每一侧河岸的物种出现。在局部尺度上，不同的环境预测因子影响了河岸之间或甚至沿河岸的群落组成。这些发现表明，环境过滤是上马德拉河蜥蜴群落空间结构的主要原因，但预测变量不能在广泛的（近 500 公里）研究区域内推广。基于单个研究系统，我们证明了靠近上马德拉河河岸森林的蜥蜴群落不是随机结构的，而是对不同和层次化空间尺度上的多种因素做出响应。
