Litterfall as an indicator of productivity and recovery of ecological functions in a rehabilitated riparian forest at Das Velhas River, southeast Brazil.

Abstract

Effectiveness of litterfall in restoration of Das Velhas River riparian forest in Brazil and the use of non-foliar fractions of litter as an indicator of recovery of ecological functions were evaluated from November 2011 to October 2012. One litterfall collector of 0.25 m2 was placed in the center of each of the 15 noncontiguous 100 m2 plots to sample litterfall monthly. Litter was sorted into leaves and non-foliar fractions, branches, reproductive organs and others; oven dried and weighed in precision scales. We calculated total annual litter production by fractions. Annual litterfall was high (8.4 Mg ha-1 yr-1) and similar to that of primary and secondary riparian forests in studies conducted elsewhere. Non-foliar fractions represented 35.7 % of the litterfall and showed that not all planted species are reproducing yet. The results indicated that both avifauna and insects are contributing to functional diversity. The largest input of litterfall occurred in July and August, which are the driest months. Thus, litter production has been influenced by hydric seasonality, and also by edge effects, once the forest is narrow (< 50 m) and can be considered itself as an “edge”. Litterfall was a useful indicator, showing that forest was productive and the litter fall was contributing to the nutrient cycle. Non-foliar fractions indicated the recovery of ecological functions in the forest, suggesting that litterfall can be used as indicator of restoration of ecological services.