Effects Of Intra-species Variation On Functional Diversity And Community Assembly In The Inner Mongolia Grassland

In the face of the unprecedented loss of biodiversity,diversity pattern and community assembly have become the focus of ecological research.The functional traits of plants reflect the adaptive strategies and trade-offs among different internal functions produced by plants in the process of environmental changes,which are helpful to predict the changes of ecosystem functions or processes.However,previous studies on functional diversity and community assembly were mostly based on average traits of species in the sample plots,mainly focusing on interspecific variation.Whereas,in recent years,it was found that intraspecific variation was also one of the influencing factors that could not be ignored.Therefore,considering intraspecific variation is very important for functional diversity and community assembly,which is conducive to a more complete and systematic understanding of biodiversity formation and maintenance process.In this study,23 the sites were selected based on the availability of individually fenced enclosures pastures that had experienced no grazing for many years from the meadow steppe,typical steppe and desert steppe in Inner Mongolia and investigates the ecological communities located in the plots and measure 10 the plant functional characters((plant height(PH),leaf area(LA),single leaf dry matter content(LDMC),specific leaf area(SLA),leaf nitrogen content(LNC),leaf phosphorus content(LPC),leaf carbon content(LCC),leaf carbon and nitrogen ratio(C/N),leaf nitrogen and phosphorus ratio(N/P)and specific leaf weight(SLW)).Firstly,the variation degree of different functional traits and the contribution of intraspecific variation to community variation were evaluated according to the variation coefficient of the community weighted mean.Secondly,the influence of intraspecific variation on the measurement of functional diversity(functional richness,functional evenness and functional dispersion)and its response to aridity was discussed.Finally,the community assembly mechanism and the role of intraspecific variation in Inner Mongolia grassland were revealed.The main conclusions are as follows:(1)The functional variation of intraspecific variation that was considered was generally higher than the functional variation that was not considered.Whether intraspecific variation was considered or not,intraspecific variation was different among different traits,and the maximum leaf area was 0.589.The lowest carbon content of leaf is 0.040.(2)The contribution rate of intraspecific variation to the whole variation of Inner Mongolia grassland community is 43%.The contribution rate of intraspecific variation of different single functional traits to the whole variation of the community was different,which had obvious character dependence.(3)Intraspecific variation had a significant effect on the measurement of functional diversity and had different effects on the three aspects of functional diversity.The functional richness and functional evenness considering intraspecific variation was lower than that without intraspecific variation.The functional dispersion of intraspecific variation was higher than that of intraspecific variation.(4)Functional richness and functional dispersion increased with the increase of humid conditions,while functional evenness decreased with the increase of humid conditions.Intraspecific variation changed the response of functional diversity to humid conditions.Intraspecific variation enhanced the response of functional richness and functional dispersion to humid conditions,but decreased the response of functional evenness to humid conditions.(5)Environmental filtering was the main driving force for the community assembly in Inner Mongolia,and the environmental filtering was weakened with the increase of humid conditions.In Inner Mongolia grassland community,the selection of intra-specific variation inhibition environment plays an important role,and the inhibition effect decreases with the increase of humid conditions.