中亚热带喀斯特森林树木功能型的生态位特征OACSTPCD

[Objective]By analyzing the niche characterization of tree functional types(TFTs)in a central subtropical karst forest,we can infer the differences in resource utilization and interspecific competition among different TFTs,providing theoretical guidance for vegetation restoration and reconstruction in karst areas.[Method]Based on plot surveys in the subtropical karst evergreen-deciduous broadleaved mixed forest in central subtropical China,the 40 tree species were selected and classified into different functional types according to canopy height,population size,shade tolerance,and seed dispersal mode.The niche characterization of the tree species in different functional types were analyzed by measuring niche breadth and niche overlap index.[Result]The niche breadths of tree species in the karst forest are generally low,with the ranking of common species>occasional species>rare species,and there are significant differences among them.The niche breadths of gravity dispersed species are significantly lower than those of animal dispersed and wind dispersed species,while there are no significant differences in niche breadths between different TFTs with different shade tolerance and canopy height.The niche overlaps among the 40 tree species are also low,with significantly higher overlap between common species compared to occasional and rare species,and significantly higher overlap for overstory species compared to understory species.Light demanding species have significantly higher overlaps compared to shade tolerant species,while gravity dispersed species have significantly lower overlaps compared to animal dispersed and wind dispersed species.The overlaps between common and occasional species are significantly higher than those between common and rare species,as well as those between occasional and rare species.The overlaps between animal dispersed and wind dispersed species are significantly higher than those between animal dispersed and gravity dispersed species,as well as those between wind dispersed and gravity dispersed species.However,the overlaps between mid-tolerant and shade tolerant species are significantly lower than those between light demanding and mid-tolerant species,as well as those between light demanding and shade-tolerant species.[Conclusion]Most tree species in the subtropical karst evergreen and deciduous broad-leaved mixed forest occupy relatively small niche spaces and may have lower interspecific competition.The differences in niche breadth and overlap among different TFTs may be closely related to habitat heterogeneity and species trait differences.When conducting vegetation restoration in degraded habitats,the composition and structure of the community should be reasonably constructed based on the niche characterization of different TFTs,thereby promoting recovery of forest vegetation.