Litter fauna and decomposition experiment in coastal ecosystems of Sapelo Island

In a field study (2007-2009) on Sapelo Island, GA, USA (31°27' N, 81°15' W), we incubated two contrasting detritus types in three distinct habitat types in coastal Georgia to test the hypotheses that (1) the litter fauna composition depends on the habitat and the litter type available; and (2) litter mass loss (as a proxy for decomposition) depends on environmental conditions (habitat) and the litter type. Litter of oak (Quercus virginiana) and pine (Pinus palustris) was collected in mesh baskets placed below trees; this prevented shed leaves from falling onto the ground, and thereby limited decomposition prior to our study. Litter was returned to the laboratory and air-dried for >7 days at room temperature. Each litter type was weighed (4.00 + 0.01 g dry weight) separately into mesh bags. Bags were placed in groups of four (N = 2 litter types x 2 mesh sizes) with six replicates per habitat (saltmarsh, forest, creek bank) and sampling date, and embedded in the existing litter present at the site. Litter bags were deployed in August 2007 and removed from the field after 1 month (September 2007), 6 months (February 2008), 12 months (August 2008), and 25 months (September 2009). Litter bags were individually stored in plastic bags for transport to the laboratory, where fauna were extracted in a Berlese apparatus, and the remaining litter cleaned of soil particles, dried at 60°C for 72 hours, and weighed. Invertebrates extracted from the mesh bags were identified to the highest taxonomic level possible and assigned to one of three functional groups: detritivores, predators or omnivores.