Vegetation structural parameters affect leaf litter decomposition along a secondary successional chronosequence in tropical dry forest

Litter decomposition contributes to nutrient cycling and influences soil organic matter, affecting soil fertility. We assessed the impact of leaf quality and vegetation structure on litter decomposition across three successional stages (early, intermediate, and late) in a Brazilian tropical dry forest. A total of 315 litterbags were installed, 105 per stage, at the beginning of the rainy season, and litter mass loss was measured over 322 days. Overall, 48 % of the litter mass was lost at the end of the experiment, and decomposition was higher in late successional stage. Leaf nutrient concentrations increased along the successional gradient. Although leaf traits did not influence decomposition, vegetation structure (species richness, basal area, and height) showed a significant positive effect. The accelerated decomposition in later stages may reflect microclimatic changes and more active decomposer communities, both shaped by vegetation complexity. Our findings suggest that, even after four decades, these regenerating forests have not achieved full recovery of vegetation structure or decomposition-related ecosystem functioning.