Divergent Drivers of Litter Decomposition in Karst and Non-Karst Tropical Rainforests: A Comparison

Litter decomposition is pivotal in nutrient cycling, with this process being influenced by numerous factors. However, the factors and pathways driving litter decomposition in certain heterogeneous ecosystems, such as diverse tropical karst ecosystems, remain unclear. We conducted litter decomposition experiments, both in situ and reciprocal transplants, in the seasonal rainforests of karst (KF) and non-karst (NKF) regions. While the litter N :P emerging was the most determinant influencing factor driving litter decomposition acorss both KF and NKF, other key drivers of in litter decomposition differ significantly between KF and NKF, with. In KF, The topography results in an uneven distribution of water and heat, which drives various factors such as tree diversity, leaf structure, and decomposer feeding, all influencing litter decomposition processes. In NKF, tree diversity, soil nutrients, and other abiotic factors exert relatively uniform effects on decomposition, with no single factor standing out as particularly dominant. The difference between KF and NKF might result from the fact that phosphorus resources are primarily acquired through leaf reabsorption in KF while NKF trees obtain phosphorus through root absorption, which leads to an opposite trend between litter total P and tree diversity in KF and NKF. Even though the decomposition pathways in KF and NKF differ significantly, we did not observe a home-field advantage. This study reveals the driving factors of litter decomposition in karst and non-karst ecosystems, highlighting the pivotal role of nutrient acquisition strategies in shaping decomposition pathways. It provides a foundation for future research aimed at enhancing forest management practices and optimizing nutrient cycling strategies in diverse tropical environments.