Comparative leaf litter decomposition dynamics under native and invasive canopies in a semi-arid forest ecosystem

The decomposition of leaf litter regulates nutrient cycling, carbon turnover, and soil fertility, in resource-limited semi-arid ecosystems, where resource-limited conditions intensify ecological responses. In this study, we estimated the decomposition patterns and nutrient release scheme of leaf litter from five woody species (Cassia fistula, Pongamia pinnata, Azadirachta indica, Acacia leucophloea, and Leucaena leucocephala) and the invasive Prosopis juliflora in the Delhi Ridge using litterbags (5 g air-dried litter per bag). Decomposition was enhanced under the P. juliflora canopy, with a lower mean residual litter weight (2.16 g) than that of the native canopies (2.69 g). Percent mass loss, decay constants, and decomposition rates were significantly higher in the presence of P. juliflora, with the maximum decomposition rate observed for P. juliflora litter (16.11%/month, decay constant (k) = 0.59), and the lowest for C. fistula (8.91%/month, k = 0.29). Nutrient release followed the order K > P > N, with more rapid nitrogen and phosphorus mineralization under the P. juliflora canopy. The decomposition rate was positively correlated with the initial litter N and P content (R2 = 0.90) and negatively correlated with the C/N and C/P ratios.