Canopy gaps control litter decomposition and nutrient release in subtropical forests

Abstract Aims Forest litter plays a critical role in the nutrient cycle of forest ecosystems, and the changes in the microenvironment brought about by the formation of a canopy gap affect litter decomposition and nutrient release. However, the pathway through which canopy gaps influence litter decomposition and nutrient release remains insufficiently understood, which limits our understanding of the relationship between forest soil material cycling and the environmental heterogeneity of canopy gaps. Methods Here, we collected samples of the leaf and branch litter of Castanopsis kawakamii natural forest during decomposition for a whole year, aiming to explore the characteristics of litter mass remaining and nutrient release in canopy gaps and non-gaps. Meanwhile, combined with environmental factors, taxonomic diversity, and soil microbial diversity, we aimed to reveal the primary factors influencing litter decomposition for leaf and branch litter. Results We found that the litter mass remaining of leaves and branches in medium gaps (50–100 m2) was lower than that of other gaps, and the leaf litter decomposition rate was higher than that of branch litter decomposition. Likewise, litter mass remaining, total carbon and nitrogen release, and enrichment were found to be asynchronous. Conclusions We highlight that the environmental heterogeneity caused by gap sizes significantly influenced the soil microbial community activity and taxonomic diversity. Furthermore, the asynchronous nature of taxonomic diversity and soil microbial diversity depending on canopy gap size affected mass remaining and nutrient release for both leaf and branch litter, thus comprehensively influencing litter decomposition and nutrient release in subtropical forests.