Distribution patterns and driving factors of fruit tree richness in North China

Under the current backdrop of increasingly variable climatic conditions, the distribution patterns and driving factors of fruit tree richness in North China remain insufficiently understood, yet fruit tree diversity is critical for agricultural biodiversity and regional food security, and systematic studies integrating both natural and anthropogenic drivers are lacking in this region. In this study, we integrated distribution data of 14 major fruit tree species with climate, terrain, soil, and anthropogenic variables, covering North China (Beijing, Tianjin, Hebei, Shanxi, Shandong, and Henan provinces, approximately 1.18 million km²). Potential suitable habitats were simulated using the MaxEnt model to estimate fruit tree richness, and the Geodetector together with structural equation modeling (SEM) was applied to disentangle the multi-factor driving mechanisms. The results indicated that: (1) the simulated distributions of the 14 fruit tree species achieve high accuracy, with most species exhibiting AUC values above 0.8; (2) high fruit tree richness in the North China region is mainly concentrated in hilly and mountainous areas such as the eastern Taihang Mountains, the Shandong Hills, and Jiaodong Peninsula; (3) among individual environmental contributions, population density, annual mean temperature and nighttime light most frequently rank among the top three contributors across 14 species, with anthropogenic and topographic variables jointly governing fruit-tree habitat suitability in North China; (4) the interaction between climate and anthropogenic was strongest, with anthropogenic factors showing both direct negative associations with fruit tree richness and indirect pathways via climate and soil, whereas climate is positively associated with fruit tree richness. These findings demonstrate that anthropogenic factors, rather than purely natural conditions, dominate the spatial patterns of fruit tree richness in this intensively managed agricultural region. This study enhances understanding of the distribution of fruit tree richness in North China, clarifies the multi-factor mechanisms shaping its spatial patterns, and provides a useful reference for understanding how multiple environmental and anthropogenic factors are associated with fruit tree distribution, which may inform future studies and region-specific management strategies.