Are Cecropia trees ecosystem engineers? The effect of decomposing Cecropia leaves on arthropod communities

Ecosystem engineers structure species richness and the composition of biological communities. Although several studies have uncovered the importance of engineering environments, few studies have evaluated the effect of pioneering plants as ecosystem engineers, especially in tropical environments. When dead, Cecropia leaves become architecturally complex, acquiring a tridimensional shape due to desiccation, and may facilitate other organisms. Here we evaluate the role of these dead leaves in structuring species richness, abundance, biomass, and composition of macroinvertebrate communities on leaf litter in six protected areas of Brazilian Atlantic Rainforest. Predators were larger, more abundant, and presented higher standing stock in the presence of dead Cecropia leaves compared to soil debris (i.e., common leaf litter); however, detritivores had the opposite patterns. This resulted in shifts in body size structure of the assemblage, thus causing inversion of biomass pyramids to top-hea...