Scale-dependent dispersal limitation in soil nematode community assembly across agricultural ecosystems

Soil nematodes, which are the most prevalent and widespread group of soil fauna, play a crucial role in maintaining soil health and supporting agricultural productivity. Despite their importance, the mechanisms underlying the assembly of soil nematode communities in agricultural ecosystems, particularly how these mechanisms vary across different spatial scales, remain poorly understood. In this study, we examined the community assembly processes of soil nematodes across a geographical span of 4,138 km, covering multiple spatial scales within agricultural ecosystems. Our findings highlight a distinct scale-dependent pattern in the assembly of soil nematode communities, with dispersal limitation becoming increasingly dominant as spatial scale expands. Additionally, we identified soil nitrogen, total phosphorus, and precipitation as key drivers influencing the variability in these assembly processes across spatial scales. This study provides novel insights into the spatial dynamics and scale-dependent community assembly of soil nematodes, with important implications for predicting changes in their ecosystem functions in response to future environmental changes.