The Phylogenetic Structure And Functional Diversity Of Anthropogenic Disturbance Communities In Baiyunshan Nature Reserve

Various ecological and evolutionary processes are thought playing an important role in maintaining the species diversity of higher plant communities in the forest.An understanding of the phylogenetic structure of an ecological community can provide insights into the relative importance of different processes structuring that community.Meanwhile,The destruction of the natural environment by human activities has increased dramatically.Forests have been destroyed in large numbers.The stability of ecosystems and the coexistence of community species have been seriously threatened.The community restoration and succession process can be more clearly understood,and the ecosystem function can be understood by studying the dynamic development of the phylogenetic and functional structure of forest communities which are with different levels of disturbance intensity.Therefore,there are great significance for the conservation and utilization of biodiversity.In this study,Based on the data of 7ha dynamic monitoring sample plot in Baiyun Mountain Nature Reserve.We estimated phylogenetic structure by comparing observed phylogenetic distances among species with the distribution of phylogenetic distances under two different null models undergoing different spatial and time scales in the plot;At the same time,the functional traits of species in different disturbance gradient communities were measured in this study.The phylogenetic signals of species functional traits in Baiyunshan Nature Reserve were tested using the “K-value” method;The functional richness(FRic)index,functional evenness(FEve)index,functional dispersion(FDiv)index,and quadratic entropy Rao's index were calculated using species functional traits and species species abundance information.This study find that:(1)In the 10 × 10 m,20 × 20 m,and 25 × 25 m spatial scales,the community phylogenetic clustering intensified with the scale expansion,and the habitat filtering effect was obvious;(2)At the middle and small diameters,the phylogenetic clustering intensity increased with the increasing of the diameter class,but the clustering intensity of the large diameter class communities does not change significantly,and at large scale,the size of the large diameter class is less than the middle diameter class,and there is obvious competition on the time scale.(3)With the increase of disturbance intensity,the community showed a trend of phylogenetic overdispersion.The results of multiple comparisons showed that the community phylogenetic structure of plantation and old-age forests had significant changes,and the phylogenetic structure of the community between the deforestation and the clear-cutting forests did not change significantly.The results of the comprehensive phylogenetic indicated that competition exclusion and habitat filtration were the main driving forces for the establishment of communities in this region.The niche theory is an important mechanism for maintaining the diversity of forest communities in Baiyun Mountain deciduous broad-leaved forest.(4)Significant developmental signals of functional traits were detected in different disturbance gradient communities(p<0.05).The species functional traits in this area were greatly affected by the phylogenetic developmental history,and the species niche was conservative.However,there are significant differences in the development signals of different functional disturbance traits.The oldest forest K value indicates that the old-age forest community environment is so relatively stable that the functional traits of the species within the community are less affected by the environmental differences.(5)In the study of functional diversity index of different communities,it was found that the interference gradient had a significantly impact on the species diversity of species in the community.Due to human intervention and tending,artificial forests had the highest resource utilization rate and the most abundant use of resources.Strong interference will seriously affect the utilization of community resources.However,the utilization rate of type IV old-age forest plots is not high,which may be due to the highest altitude,the largest gradient,and the strong heterogeneity of habitats,resulting in insufficient and uneven use of environmental resources.The results of this study indicate that the species niche is conservative,and the ecological niche theory is an important ecological mechanism to maintain the diversity of forest communities in Baiyun Mountain deciduous broad-leaved forest.The structure of functional traits in this area varies significantly with the change of disturbance gradient,and the strong disturbances are not conducive to the restoration of forest communities.It is hoped that the study will provide a scientific theoretical basis for the rational use of forest resources in the region and the research and protection of biodiversity.