Aims: Tropical peatlands have a globally important role as carbon sinks. How their waterlogged conditions and low nutrient status impact plant litter decomposition is not well-understood, despite decomposition processes underpinning carbon sequestration. Our study explored leaf litter decomposition between adjacent paired patches of intact tropical peat forests and kerangas (free-draining heath) forests in Brunei Darussalam and tested the 'home-field advantage' effect, which predicts that litter decomposes fastest in the environment it was sourced from due to pre-adaption of the decomposer community.

Methods: A litter reciprocal transplantation decomposition experiment was conducted across paired peat and kerangas plots using litter from five tree families (Euphorbiaceae, Fabaceae, Lauraceae, Dipterocarpaceae, and Myrtaceae), common to both forest types.

Results: Contrary to expectations, we found no significant difference in rates of mass or nutrient loss from decomposing litter between peat and kerangas forests irrespective of the litter's origin, despite differences in environmental conditions between the two environments. We also found no evidence for home-field advantage in either forest. Litter nutrient concentration operated as a key predictor of decomposition, but this effect was independent of forest type.

Conclusions: The study suggests that differences in surface leaf litter decomposition are unlikely to greatly contribute to the high organic matter accumulation observed in peat forests relative to kerangas forests, indicating that other factors, such as woody debris, branches and tree trunks are more likely to be contributing to their belowground carbon sequestration. This emphasizes the need for further research to explore factors driving organic matter accumulation in tropical peatlands.