How does leaf litter chemistry influence its decomposition and colonization by shredder Chironomidae (Diptera) larvae in a tropical stream?
The nutritional quality of leaf litter can influence shredder chironomid larvae activities and affect leaf litter decomposition in tropical streams. The invasion of riparian areas by exotic plants may alter the nutritional quality of allochthonous material in streams, which would influence litter decomposition in these systems. We carried out an in situ experiment to verify the relationship between the initial leaf litter chemistry of two invasive plants (Hedychium coronarium and Pteridium arachnoideum) and a native one (Magnolia ovata) and the shredder chironomid larvae density and decomposition rates in a tropical stream. We found differences in the initial leaf litter chemistry and mass loss between leaf litter species. Differences in leaf litter chemistry influenced the colonization behavior by chironomid larvae. Larval densities differed among litter species, both taxonomically and functionally. The density of shredders was similar between M. ovata and H. coronarium, although they were colonized by different taxa: Endotribelos was more abundant in M. ovata and Stenochironomus in H. coronarium. P. arachnoideum was colonized by fewer shredders probably due to its high secondary compounds and lignin concentration. The invasion of riparian areas by exotic plants can alter the colonization of chironomid shredder assemblages and therefore the decomposition rates in aquatic systems.