Assessing the fine-scale effects of bamboo dominance on litter dynamics in an Amazonian forest

Abstract

Bamboo dominance drives changes in vegetation structure and plant biodiversity in many tropical forests worldwide. However, the effects of bamboos on ecosystem functions have received less attention or have been investigated in degraded forests. Here, we assessed the effects of the dominance of the native bamboo Guadua weberbaueri on litterfall, litter layer and decay of leaf litter in an Amazonian forest free from major disturbances. We aimed to understand whether bamboo dominance changes the litter dynamics on a fine spatial scale. Specifically, we tested the hypothesis that bamboo-dominated (BD) forest areas have (i) less litterfall, (ii) greater litter layer thickness and (iii) less decay of leaf litter necromass compared to adjacent bamboo-free (BF) forest areas. Over a year, the BD forest area produced less litterfall and accumulated a thicker litter layer compared to the adjacent BF forest area; however, the decay of leaf litter necromass did not differ between the BD and BF environments. Our results suggest that the bamboo dominance in Neotropical forests decreases litterfall and increases the litter layer thickness, which should deplete the nutritional return in these systems over time. Furthermore, we show that these effects also occur in forests that are not subject to major disturbances and that they can be seen even at small spatial scales.