Invertebrate colonisation during leaf processing of native, exotic and artificial detritus in a tropical stream

Abstract

The relationship between leaf breakdown and colonisation by invertebrates in tropical aquatic ecosystems is poorly understood, especially in regard to the added problem of the potential effects of exotic species. To assess the colonisation by invertebrates during leaf breakdown in a third-order headwater stream in south-eastern Brazil, we conducted an experiment using the native species Miconia chartacea, the exotic species Eucalyptus grandis and artificial leaves. We hypothesised that the quality of the detritus and the leaf shape influence invertebrate colonisation because of the quality of the food and refuge offered by leaf detritus. Invertebrate density and richness were higher on leaves of E. grandis than on those of M. chartacea. Taxon richness did not differ among M. chartacea and the two sizes of artificial leaves offered, probably as a function of the chemical composition of E. grandis. Total invertebrate density was significantly higher in the organic detritus, suggesting that detritus provides food for the organisms. Our results indicate that the colonisation of invertebrates is probably affected by the chemical composition of detritus. Contrary to expectations, the community of invertebrates had no difficulty in colonising E. grandis, although it is an exotic species. In addition, the shredder activity did not influence leaf breakdown. These results may indicate that the invertebrates in this stream tend to behave as generalist feeders.

Are sugarcane leaf-detritus well colonized by aquatic macroinvertebrates?

“…Capello et al (2004) reported similar observations in his study of the decomposition of leaf-detritus of Salix humboldtiana. Similarly, Gonçalves et al (2012) attributed the changes of the physical state of detritus and faunal composition to the natural degradative succession process: a la llanura aluvial del rio Paraná Medio. Amazoniana,vol.…”

“…Furthermore, a GLM was performed in the period of the peak colonization, to each functional feeding group, to compare the two types of leaf-detritus. To evaluate the effects of the plant detritus, sampling periods and interaction between these two factors on the functional structure of the community, was used a MANOVA/Pillai Trace test (Scheiner, 2001;Gonçalves et al, 2012).…”

Experimental assessment of temperature increase and presence of predator carcass changing the response of invertebrate shredders

“…The chemical composition of the leaf influences the selection of plant species by the invertebrate as resource or shelter (Wright & Covich 2005, Graça et al 2001, Gonçalves Junior et al 2006. However, the studies are still not sufficient to help understand the interaction mechanisms between the invertebrate shredders, quality of the litter and temperature in headwater streams.…”

“…The role of these invertebrate shredders in leaf breakdown in tropical lotic ecosystems has been explored recently (Wright & Covich 2005, Gonçalves Junior et al 2006, Wantzen & Wagner 2006, indicating the leaves may provide both food and habitat (Ruetz III et al2006, Leroy & Marks 2006, Moretti et al 2009, Gonçalves Junior et al 2012. The chemical composition of the leaf influences the selection of plant species by the invertebrate as resource or shelter (Wright & Covich 2005, Graça et al 2001, Gonçalves Junior et al 2006.…”

Aquatic macroinvertebrate colonization of artificial substrates in low-order streams

“…Mining and shredding groups, for example, are easily found in colonization experiments that use plant detritus as substrate (CLAPCOTT;BUNN, 2003;GONÇALVES et al, 2012;LEITE-ROSSI;TRIVINHO-STRIXINO, 2012). Organisms such as Simuliidae larvae and pupae have a habit of attaching to hard substrates, and are found only in experiments using material such as stones, strips of polyethylene, and expanded clay (PEPINELLI; TRIVINHO-STRIXINO, 2002).…”