Abiotic factors and trophic interactions affect the macroinvertebrate community of bromeliad tanks in a Neotropical Restinga

Aquatic macroinvertebrate communities are dependent on intrinsic environmental characteristics and biological interactions in microhabitat systems. We investigated the species-area relationships, detritus content input and trophic interactions of macroinvertebrate fauna in 46 Vrieseae friburguensis in a Restinga environment. Our hypotheses are that (i) bromeliad water volume and detritus content would positively affect the macroinvertebrate richness and abundance; (ii) predators would exercise a top-down effect on macroinvertebrates community; but (iii) will control the prey in different ways, due to the preference to occupy and stay in a spatial position on the bromeliad tank. We found 2201 macroinvertebrates from 18 taxa (12 preys and 6 predators). Higher water volume, detritus content and bromeliad area increased the richness and abundance of macroinvertebrates. Culicidae (swimming preys) coexist with predators due to the segregation in the use of the water column caused by the presence of Chironomidae (browsing preys). The opposite response of browsing and swimming preys to predator abundance suggests that trophic interactions are more important to swimming preys than for browsing ones, and this latter is more related to abiotic factors. Therefore, abiotic factors (mainly, water volume) and trophic interactions (abundance of predators) drive the macroinvertebrate community of bromeliad tanks in the studied Neotropical Restinga.