Plant functional traits affect invertebrate predator diversity via bottom-up effects in a deadwood-based food web

Bottom-up effects play a critical role in shaping community structure and trophic interactions within detritus-based food webs. Coarse deadwood supports high biodiversity and contributes to detrital food webs during its decomposition process. Previous experiments have shown that wood functional traits have significant impacts on detritivore communities. However, this effect has rarely been tested on higher trophic levels, even less so relationships between plant functional traits and predators via detritivores. In this study, we investigated the effects of wood functional traits, synthesized into the wood economics spectrum (WES), on the abundance and diversity of detritivores and predators throughout the decomposition process of 22 different tree species in eastern China. We hypothesized that the WES has strong direct effects on detritivores and indirect effects on predators as mediated by detritivores. We found that the WES affected detritivore abundance and richness during early and intermediate periods of decomposition, with tree species representing a ‘resource-acquisitive’ strategy having higher detritivore abundance and diversity. The WES had almost no significant direct effects on predator communities, while detritivore abundance and richness had positive effects on predators. Thus, the WES affected predator communities indirectly through detritivores, yet with differences between sites and across decomposition periods. Our study emphasizes the importance of ‘afterlife effects’ of wood traits for detrital food webs affecting not only detritivores but also higher trophic levels and suggests that bottom-up effects are the underlying mechanism. To effectively conserve biodiversity associated with deadwood, forest management and restoration should prioritize maintaining high tree species diversity covering the full WES, ensuring diverse habitat and resource availability for multiple invertebrate groups. Read the free Plain Language Summary for this article on the Journal blog.