Study On The Relationship Between Species Abundance And Environmental Niche And Functional Niche Differentiation Of Subtropical Evergreen Broad-leaved Forest In Gutian Mountain

Forest community biodiversity and maintenance mechanism are the core of community ecology research.Understanding the mechanism of biodiversity maintenance contributes to the sustainable development and utilization of biodiversity and effective conservation.Interspecific differentiation refers to differences in phenotype or gene among species.General traditional community ecology studies often regard species as a collection of the same individuals.This ignores the effect of intra-species differentiation on species coexistence.With the development of individual differentiation research in recent years,ecologists have realized that the differentiation of intra-species functional traits in a community can not only affect the evolutionary process of population and community,but also affect the species coexistence in communities.Changes in plant functional traits can reflect the extent and speed of vegetation response to the environment.A major salient problem of community ecology based on functional traits is our ignorance of the relativeimportance of intra-species functional traits and how to combine information from intra-specific variation to help us understand the pattern and dynamics of communities.Intraspecific functional traits are considered to reflect the results of plant competition.So ecologists are becoming increasingly interested in the relationship between the intraspecific variation of species traits and the abundance of species,and how common species and rare species in plant communities are distributed in functional space.Based on the above-described lines of reasoning,this study collected functional traits such as leaf area,leaf area,wood density,stomatal density,relative chlorophyll content,leaf nitrogen content,leaf phosphorus content,and nitrogen phosphorus ratio in 24 ha forest plots in Gutian Mountain in 2015.The niche width and niche position were in environmental space were calculated using ENFA(ecological niche factor analysis),and the phylogenetic generalized least squares method and the generalized linear mixed model were used to analyze the relationship between species abundance and intraspecific trait variation and niche position in functional space.The results showed that:(1)Intraspecific variation of functional traits was negatively correlated with species abundance.This that indicates dominant species have smaller niche width,whereas rare species have larger niche width;(2)The deviations of from mean trait value of a community were negatively correlated with the species abundance.This indicates that dominant species occupy central position,whereas rare species utilize marginal position.(3)In environmental space,the niche specialization and niche marginality of a species were negatively correlated with species abundance.This indicates a different result from that in functional space tihat dominant species occupy central position with larger niche width,whereas rare specie utilize marginal position with smaller niche width.(4)Functional niche and environmental niche can explain 22.5%and 22.0%of species abundance respectively.This indicated that the dominant species have a lower change in their traits(eg,growth),suggesting that their traits have been adjusted to the local optimal competitive phenotype or have been able to take advantage of the favorable local environmental resource sites.Rare species use rare resources in space or time.Rare species may have phenotypes that are not suitable for most of the available environments,and are more subject to phenotypic constraints or specificity,and they are struggling to adapt to existing environments.Therefore their traits may have greater differentiation,thereby limiting their competitiveness and proliferation.In this study,we analyzed the relationship between species abundance and the intraspecific differentiation of functional traits,and found that the dominant species occupy central position with smaller intraspecific variation in functional space,whereas rare species use marginal position with larger intraspecific variation.The maintenance mechanism of diversity were explored from the perspective of intra-specific functional traits.Our study provides basis for the understanding of the biodiversity maintenance mechanism in subtropical forests.