Natural lentic microhabitats are important for aquatic invertebrate communities in subtropical aquatic systems, which are usually dominated by mosquitoes, predators and zooplankton. Subtropical lentic microhabitats might be strongly affected by top-down effects of predators. We evaluated the predator effects on aquatic macroinvertebrate and zooplankton communities by using black plastic buckets (10 L) to simulate lentic microhabitats, which were divided into four treatments: predator absence and presence, and initial (on experiment start) and final (on experiment end) community controls. Large top predators (Odonata) had a stronger effect on community structure by their sit-and-wait predatory behaviour. The richness of total macroinvertebrates, Culex genus (most abundant organism), and zooplankton was highest in predators' absence. On the other hand, the sit-and-wait behaviour increased the density of organisms by selective predation on macroinvertebrates that feed in the bottom of the system. Also, the sit-and-wait behaviour increased the density of gathering and filtering collectors (top swimmers) by differences in space preference. We observed a positive species-specific relationship between Culex and predators. We concluded that predators' presence contributes to the balance of lentic microhabitat in subtropical lentic microhabitats by top-down control.

中文翻译：

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自上而下对亚热带低温微生境水生群落的影响

天然静息微生境对于亚热带水生系统中的水生无脊椎动物群落很重要，亚热带水生系统通常以蚊子、捕食者和浮游动物为主。亚热带低温微生境可能会受到捕食者自上而下效应的强烈影响。我们通过使用黑色塑料桶 (10 L) 模拟慢生境微生境来评估捕食者对水生大型无脊椎动物和浮游动物群落的影响，将其分为四种处理：捕食者不存在和存在，以及初始（实验开始时）和最终（实验结束时） ) 社区控制。大型顶级捕食者（Odonata）通过坐等捕食行为对群落结构产生更强的影响。总大型无脊椎动物的丰富度，库蚊属（最丰富的生物），浮游动物在没有捕食者的情况下最高。另一方面，坐等行为通过选择性捕食以系统底部为食的大型无脊椎动物增加了生物体的密度。此外，坐等行为通过空间偏好的差异增加了收集和过滤收集器（顶级游泳者）的密度。我们观察到库蚊与捕食者之间存在正的物种特异性关系。我们得出结论，捕食者的存在通过自上而下的控制有助于亚热带 lentic 微生境中的 lentic 微生境的平衡。