林分空间结构多样性与物种多样性对空间尺度的响应OA

To explore the patterns of spatial structure diversity and species diversity in forest stands at varying spatial scales and to elucidate their interrelationships,this study selected the 6 hm2 permanent plot in the Qizimei Mountain Nature Reserve in southwestern Hubei as the research object.Using a forest stand spatial structure diversity measurement method based on the neighborhood relationships of four adjacent trees,along with Spearman correlation analysis,this study assessed the spatial structural diversity and species diversity across scales ranging from 20 m×20 m to 120 m×120 m.The study further examined the scale-dependent correlations between these two aspects.The results showed that the subtropical evergreen deciduous broad-leaved mixed natural forest in the study area exhibited high species richness,which increased as the spatial scale expanded and thus the community stability progressively enhanced.The stand spatial structural diversity presented favorable conditions across all observed scales,reaching a relatively stable state on the scale of 120 m×120 m.On this large scale(120 m×120 m),the Shannon-Weiner index(H)showed positive correlations with average species number of structural unit((S))and tree species richness of structural unit(SSR)(P<0.05).Conversely,on multiple scales≥40 m×40 m,it exhibited negative correlations with the average number of forest layers of structural unit((N)C),uniformity of structural unit(NSE),richness of structural unit(NSR),diversity of vertical structure(DFSv),and diversity of stand spatial structure(DFS)(P<0.05).The Simpson index(D)displayed negative correlations with average number of forest layers of structural unit((N)C),richness of structural unit(NSR),diversity of vertical structure(DFSv),diversity of horizontal structure(DFSh),and diversity of stand spatial structure(DFS)on the scales≥80 m×80 m(P<0.05).The Pielou index(J)showed similar negative correlations as the Simpson index on the scales≥100 m×100 m(P<0.05),while showing comparable positive correlations to the Shannon-Weiner index on the scale of 120 m×120 m(P<0.05).