地层岩性对森林群落生态位的影响OACHSSCD

Geological substrate is widely recognized as a crucial driver of forest ecosystem patterns.However,the precise mechanisms through which bedrock lithology governs species coexistence and niche differentiation remain insufficiently understood.Current research predominantly focuses on macro-scale impacts or is geographically skewed towards extreme environments such as karst landscapes.Consequently,a systematic understanding of the ecological effects of widely distributed representative rock types in subtropical regions remains deficient,impeding the formulation of science-based,site-specific ecological restoration and forest management strategies.To address these limitations,this study provides a systematic investigation into how three widespread lithologies-granite,slate,and sandstone-shape forest community assembly in a representative subtropical region.Our research,conducted in the forests of Changsha County,China,uniquely employs niche theory to dissect the intricate"bedrock-soil-vegetation"cascade,moving beyond descriptive analysis to elucidate the underlying processes of interspecific competition and niche differentiation.We established a comprehensive field survey across the three distinct lithological zones,meticulously documenting species composition and abundance within the tree,shrub,and herb layers.To forge a direct link between geology and biology,we analyzed the physicochemical properties of soil profiles and the elemental composition of the underlying parent rock,subsequently quantifying niche breadth and overlap for dominant species to enable a robust comparison of resource utilization strategies.The findings demonstrate a profound,cascading influence of bedrock,which directly dictates soil conditions:slate weathers into a substrate with superior water and nutrient retention,while granite produces a comparatively coarse and infertile soil.Consequently,these edaphic differences drive the formation of distinct plant communities:granite areas were dominated by Pinus massoniana,slate areas by Cunninghamia lanceolata,and sandstone areas exhibited a co-dominance of both species.Specifically,the slate-derived substrate,due to its superior water and nutrient retention capacity,created a significantly broader niche space,resulting in higher species richness,wider niche breadths,and greater niche overlap compared to the other two lithologies,particularly the granite areas which were limited by impoverished soils.Furthermore,our analysis revealed that,with the notable exception of the granite herbaceous layer,all studied communities exhibited high niche overlap,indicative of intense interspecific competition and dynamic community succession.Simultaneously,the niche space of the herbaceous layer was distinctly compressed by the dominant overstory canopy across all sites.The study demonstrates that bedrock lithology is a primary and critical factor in regulating species coexistence and resource allocation strategies within subtropical forest communities.These findings provide a robust scientific basis and essential reference for the'site-species matching'principle,offering crucial guidance for developing precise ecological restoration and sustainable forest management strategies.