Invertebrate colonization during decomposition of different leaves in a subtropical stream

Abstract

The riparian vegetation is extremely important in maintaining the energy flow in headwaters streams. Thus, the decomposition process is fundamental and depends of biotic and abiotic factors. Leaf decomposition in a water system is influenced by the chemical characteristics of plant species and the fauna composition. The aim of this study was to evaluate the composition (taxonomic and functional) of the fauna of aquatic invertebrates on leaves of Cupania vernalis (Sapindaceae) and Eucalyptus grandis (Myrtaceae) during decomposition in a subtropical stream. Senescent leaves of both species were incubated in stream and were taken after seven, 14 and 21 days for analysis of invertebrate fauna associated. The decomposition rates were similar between the two species. However, the richness and organisms density was slightly higher in C. vernalis, and presents continuous increase over time. The results demonstrated the importance of plant origin in the constitution of the riparian zone of streams. The chemical characteristics of vegetation were fundamental in changing the functional composition of aquatic fauna associated with detritus.