Land Use and Temperature Shape the Beta Diversity of Soil Nematodes and its Linkage with Soil Nutrient Cycling Across the Mollisol Zone in Northeast China

Abstract

Understanding soil biodiversity response to land use change is crucial for predicting and preserving soil ecological functions and health under anthropogenic influence. Yet, the overall effect of land use changes and climate conditions on belowground biodiversity remains insufficiently explored at large scales. Here, we studied the effect of conversion from natural soils to agricultural soils on soil nematode diversity, community assembly, and the potential relationship between nematode diversity and soil nutrient cycling across the Mollisol zone in northeast China. We found that nematode alpha diversity decreased in agricultural soils, and nematode alpha diversity did not exhibit a regular spatial pattern. For beta diversity, we found nematode community structures were significantly affected by land use change. Furthermore, climatic factors and geographic distance significantly impacted the beta diversity of soil nematodes, but not the alpha diversity. Temperature was a primary climatic determinant of soil nematode communities, while the effect of precipitation on soil nematode beta diversity was only observed in agricultural soils. Stochastic process dominated soil nematode community assembly, but agricultural soils increased the importance of deterministic process compared to natural soils. A partial least squares path model revealed that land use conversion and temperature can indirectly impact soil nutrient cycling by regulating nematode beta diversity. Our study reveals unexpected variation in soil nematode alpha diversity along the Mollisol zone, and highlights the crucial role of nematode beta diversity in maintaining soil nutrient cycling accompanying land use conversion and climate change.

Keywords: alpha diversity, beta diversity, land use, climate conditions, soil nematodes, soil nutrient cycling