Abstract Human disturbance and nutrient runoff lead to water pollution, particularly in downstream waters and reservoirs. We hypothesized that increased human activity in summer would affect the trophic state of downstream reservoirs, affecting the interannual species composition of rotifers. We used long-term data for the Unmun Reservoir in South Korea (2009–2015), which is increasingly affected by human activity. The interannual variation of nitrogen and phosphorus levels was higher in summer and autumn, resulting in eutrophication. This led to a change in species composition of rotifers. Anuraeopsis fissa, Brachionus calyciflorus and Trichocerca gracilis were abundant in the most eutrophic state, while high densities of Ascomorpha ovalis and Ploesoma hudsoni were observed when nutrient concentrations were lower. The trophic state changes in the Unmun Reservoir were largely attributed to summer human activity in tributary streams. Our study location is typical of the stream network in South Korea and we assume that similar trophic state changes in reservoirs will be common. Changes in the density and species diversity of rotifers due to eutrophication indicate the need for active management and conservation, including the restriction of human activity around streams.

中文翻译：

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轮虫群落对人类引起的水库营养状态变化的响应

摘要 人为干扰和养分径流导致水污染，特别是在下游水域和水库中。我们假设夏季人类活动增加会影响下游水库的营养状态，从而影响轮虫的年际物种组成。我们使用了韩国 Unmun 水库（2009-2015）的长期数据，该水库越来越受到人类活动的影响。夏秋季节氮、磷水平年际变化较大，导致富营养化。这导致轮虫物种组成发生变化。Anuraeopsis fissa、Brachionus calyciflorus 和 Trichocerca gracilis 在最富营养化的状态下含量丰富，而当营养浓度较低时，观察到卵形子囊菌和 Ploesoma hudsoni 的高密度。云门水库的营养状态变化主要归因于支流夏季人类活动。我们的研究地点是韩国典型的河流网络，我们假设水库中类似的营养状态变化将是常见的。由于富营养化导致轮虫密度和物种多样性的变化表明需要积极管理和保护，包括限制河流周围的人类活动。