Litterfall production in tropical natural forests on Hainan Island: variations across vegetation types and dependence on community properties

• Litterfall production features varied among vegetation types at a regional scale. • The monthly production showed either unimodal or bimodal dynamic patterns. • The monsoon rainforest displayed the strongest seasonality in litterfall production. • Stand structure was the key community property associated with litterfall production. Litterfall production is fundamental to various functions and processes within forest ecosystems. Yet, it has been primarily investigated within single vegetation types, with its dependence on biotic conditions remaining largely undefined, particularly in the tropics. In this study, litterfall monitoring and community investigations were conducted on five representative vegetation types of the tropical natural forests on Hainan Island, China, including the tropical lowland rainforest, montane rainforest, monsoon rainforest, coniferous forest, and cloud forest. On that basis, the litterfall production characteristics in the various vegetation types were distinguished, and their dependence on different community properties (species composition, species diversity, functional diversity, stand structure, and functional traits) was assessed. The lowland rainforest displayed the highest total, monthly maximum, and variance of litterfall production, followed by the montane rainforest, while the lowest levels were observed in either the cloud forest or the coniferous forest. The temporal variations turned out pronounced in all vegetation types except for the coniferous forest, which was distinguished by a unimodal pattern of litterfall dynamics. Meanwhile, a bimodal pattern was also observed, particularly prominent in the cloud forest, followed by the montane rainforest. Moreover, litterfall production characteristics significantly depended on community properties, with stand structure being the most crucial factor. Overall, these findings emphasize the considerable regional-scale variation in litterfall production across vegetation types and its dependence on community properties. From a forest management perspective, maintaining stand structural complexity contributes to sustaining nutrient return through increased litterfall production.