Key pathways of forest type conversion affecting soil detrital food webs

Detrital food webs driven by soil fauna are the essential components during litter decomposition and other material cycling processes in forest ecosystems. However, the current high-frequency and large-scale conversion of natural forests to plantations may profoundly alter the structure and function of detrital food webs. This paper systematically analyzes the effects of forest type conversion on soil detrital food webs through three pathways: litter characteristics, understory micro-environment, and energy pathways. Firstly, natural forests have relatively higher litter diversity and more stable input, which support complex trophic structures of soil fauna, but plantations often display single litter types and reduce litter quality, leading to simplified community structures of soil fauna. Secondly, compared with natural forests, plantations exhibit decreased vegetation diversity, increased microclimatic fluctuations within the forest, and deteriorated soil physical and chemical environment. These changes further weaken habitat heterogeneity and resource supply, thereby shortening the length of detrital food chains. Furthermore, there is a loss of trophic level structure (especially top predators) after the conversion of natural forests to plantations, reduced energy transfer efficiency, and limited stability of detrital food webs. Nevertheless, current studies still have many knowledge gaps, such as specific plantation tree species, multi-factor interactions, and functional quantification. It is suggested that structure-function models should be constructed by combining stable isotope technology, multi-factor experiments, and long-term observations in the future. The results will be expected to provide a theoretical basis for fully understanding the changes in ecosystem structure and function after forest type conversion, as well as for the close-to-nature management of plantations and the conservation of soil biodiversity.