Effect of vertebrate exclusion on leaf litter decomposition in the coastal Atlantic forest of southeast Brazil

Forest fragmentation is the main cause of biodiversity loss in the Anthropocene and it is triggering a top-down cascade effect that may influence leaf litter decomposition. However, the link between biodiversity loss and changes in ecosystem processes is not fully understood. We conducted an experiment to evaluate whether the exclusion of vertebrates affects the decomposition rates of different litter types (grass, a pioneer species and a mix of litters from a well preserved secondary forest). To answer this question, we placed litter bags inside artificial exclusion plots that were built in two types of vegetation coverage (abandoned pastureland and preserved forest) in the Atlantic forest of southeast Brazil. Our hypothesis is that vertebrate exclusion will change decomposition rates of different litter types due to the top-down cascade effect on soil invertebrates. We found out that vertebrate exclusion did not affect decomposition rates, possibly due to the overlap of ecological functions in the soil fauna responsible for the decomposition process. Furthermore, grass litter was decomposed faster (k value), possibly due to its initial nutrient content and hence litter quality which plays a significant role on decomposition rates.