Floodplain lakes are good metacommunity systems to study the environmental and spatial processes structuring local assemblages. They are more connected during high-water periods and are more isolated during low-water periods. We evaluated the effects of lake spatial patterning and water and sediment conditions on Unionida species assemblages. Moran Eigenvector Maps were used to generate spatial variables representing spatial patterns at different scales. We sampled 35 lakes from the Pantanal floodplain, Brazil. To understand the effects of environmental and spatial variables, we performed Redundancy Analyses and variation partitioning to separate environmental and spatial pattern effects. Environmental variables explained almost twice the variation in the Pantanal mussel assemblages than did spatial variables. Unionida species presence was driven mainly by variations in sediment coarse sand and silt contents. The weak spatial patterns observed may be related to increased connectivity between lakes during floods, which facilitates mussel host fish dispersal. Mussel abundances were driven mainly by organic matter availability, but varied between species. Changes in lake connectivity can affect the regional sediment dynamics and affect mussel assemblages.

中文翻译：

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解开水-沉积物条件和空间模式对季节性相连的洪泛平原湖泊中的尤尼尼达组合的影响

泛滥平原湖泊是研究构建当地组合的环境和空间过程的良好元社区系统。它们在高水位期间联系更加紧密，而在低水位期间更加孤立。我们评估了湖泊空间格局和水和沉积物条件对 Unionida 物种组合的影响。Moran Eigenvector Maps 用于生成代表不同尺度空间模式的空间变量。我们从巴西潘塔纳尔泛滥平原采集了 35 个湖泊。为了了解环境和空间变量的影响，我们进行了冗余分析和变异划分，以分离环境和空间模式的影响。环境变量对潘塔纳尔贻贝组合的变化的解释几乎是空间变量的两倍。Unionida 物种的存在主要是由沉积物粗砂和淤泥含量的变化驱动的。观察到的弱空间模式可能与洪水期间湖泊之间的连通性增加有关，这促进了贻贝寄主鱼类的扩散。贻贝丰度主要由有机物质可用性驱动，但在物种之间有所不同。湖泊连通性的变化会影响区域沉积物动态并影响贻贝组合。