Top‐down effects on aquatic communities in subtropical lentic microhabitats.

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. [ABSTRACT FROM AUTHOR]