Produção de serapilheira em floresta Atlântica secundária numa paisagem fragmentada (Ibiúna, SP): importância da borda e tamanho dos fragmentos

Abstract

Litter is an important compartment in tropical forests, responsible for most of nutrient cycling. Several environmental factors may affect litter production, and the ones mostly investigated are climate and vegetation structure. The influence of landscape structure on patterns of litter production is poorly studied. This study investigated edge and size effects on patterns of litter production in three Atlantic forest fragments (Ibiúna, SP: 23°35’ S-23°50’ S; 46°45’ W-47°15’ W), one large (ca. 175 ha) and two small (ca. 5 ha) with different degrees of isolation. The litter collected was fractioned following the predominant plant material, and grouped into two periods, of high and low production. We used analysis of variance and a posteriori test to detect differences in litter production between edge and center of each fragment, and among the centers of the three fragments. Most biomass consisted of “leaves+flowers”, followed by “twigs £ 0.5 cm” (62.9% and 24.7% of the total), a common pattern in tropical forests. It was possible to perceive an edge effect related to litter production in the three fragments, especially in the large one, and higher litter production in their centers. The observed patterns showed to be strongly related to the vegetation structure, as the size of trees and canopy density. A higher production of “fruits+seeds” in the large fragment or in the small and connected one indicate a relationship between forest connectivity and the activity of disperser animals.