Freshwater ecosystems are of great importance but increasingly threatened by human land uses such as intensive livestock production. We investigated the influence of cattle grazing in floodplains on the zooplankton community during a period of water retraction. We hypothesized that cattle activity in surrounding shallow lakes acts as an environmental filter for zooplankton, with its effect depending on the hydrological conditions. Accordingly, we analyzed changes in the taxonomic and functional diversity metrics in three lakes characterized by different grazing management (no-cattle; short grazing period with high stocking rates; and long grazing period with low stocking rates) over a nine-month period into three periods of water retraction (flood, early low water, and late low water). Functional diversity indexes (FRic, FEve, FDis) were influenced by grazing management and the periods of water retraction, without interactive effects, while taxonomic indices (H’, J’, D’) did not show significant relationships with any of these variables. The FRic and FDis indices decreased in lakes subjected to cattle activity, whereas FEve and FDis increased during lower water periods. Functional and taxonomic composition exhibited different patterns among lakes according to grazing management and the periods of water retraction. Overall, a similar composition was found during the flood period but it diverged in the subsequent periods of water retraction. Besides, cattle activity reduced the functional and taxonomic composition in the late low water phase. Our findings suggest that cattle activity acts as an environmental filter for zooplankton altering the functional diversity and composition through the progress of water retraction.

淡水生态系统非常重要，但日益受到人类土地利用（例如集约化畜牧生产）的威胁。我们研究了退水期间在洪泛区放牧的牛对浮游动物群落的影响。我们假设周围浅湖中的牛活动充当浮游动物的环境过滤器，其效果取决于水文条件。因此，我们将九个月内以不同放牧管理（无牛、短放牧期高放养率和长放牧期低放养率）为特征的三个湖泊的分类和功能多样性指标的变化分析为三个退水期（洪水、早期低水位和晚期低水位）。功能多样性指数（FRic、FEve、FDis）受到放牧管理和退水周期的影响，没有交互作用，而分类指数（H'、J'、D'）与这些变量均没有显示出显着关系。在有牛活动的湖泊中，FRic 和 FDis 指数下降，而 FEve 和 FDis 在低水期增加。根据放牧管理和退水时期，湖泊的功能和分类组成表现出不同的模式。总体而言，在洪水期间发现了类似的成分，但在随后的退水期间出现了分歧。此外，牛的活动减少了低水期后期的功能和分类组成。我们的研究结果表明，牛的活动充当浮游动物的环境过滤器，通过吸水的过程改变功能多样性和组成。