Deforestation of riparian areas is a major driver of biodiversity loss in aquatic ecosystems. Thus, we investigated the influence of forest cover and physical and chemical characteristics of streams on zooplankton communities in the southeastern Amazon. We addressed the following questions: (1) Are environmental factors (water physical and chemical characteristics and landscape variables) and dispersive processes (reflected in the spatial structure among sampling sites) efficient predictors of zooplankton communities in different hydrologic seasons? (2) Can zooplankton species be indicators of watersheds’ forest-cover levels? We sampled 15 streams located in nine rural settlements in northern Mato Grosso, Brazil, in the dry (August) and rainy (March) seasons of 2017. The forest-cover level had a significant effect on the physical and chemical characteristics (conductivity, dissolved oxygen, and temperature) of streams and also on the structure and composition of zooplankton communities, mainly of rotifers and testate amoebae. Areas with low vegetation cover had seasonal changes in species richness, individuals density, and zooplankton community structure. Environmental and spatial variables had no significant effect on the structure of zooplankton communities, which may indicate the strong influence of stochastic factors. Species from three zooplankton groups (rotifers, microcrustaceans, and testate amoebae) were indicators of forest-cover classes. This study provided valuable contributions to the conservation of riparian ecosystems and the use of biological indicators in environmental monitoring programs.

河岸地区的森林砍伐是水生生态系统生物多样性丧失的主要驱动力。因此，我们调查了森林覆盖率和溪流的理化特性对亚马逊河东南部浮游动物群落的影响。我们解决了以下问题：（1）环境因素（水的理化特性和景观变量）和分散过程（反映在采样点之间的空间结构中）是否有效地预测了不同水文季节的浮游动物群落？（2）浮游动物是否可以作为流域森林覆盖水平的指标？我们在2017年的干旱（八月）和雨季（三月）采样了位于巴西马托格罗索州北部九个农村居民点的15条溪流。森林覆盖水平对溪流的物理和化学特性（电导率，溶解氧和温度）以及浮游动物群落（主要是轮虫和有遗迹的变形虫）的结构和组成有重要影响。植被覆盖度低的地区在物种丰富度，个体密度和浮游动物群落结构方面存在季节性变化。环境和空间变量对浮游动物群落的结构没有显着影响，这可能表明随机因素的强烈影响。来自三个浮游动物组的物种（轮虫，微甲壳类和有遗迹的变形虫）是森林覆盖类别的指标。这项研究为保护河岸生态系统和在环境监测计划中使用生物指标提供了宝贵的贡献。