Study On Functional Characters And Functional Group Dynamics Of Different Succession Plants In Stone Desert Area Of Karst Plateau

Plant functional traits refer to a series of core plant attributes that are closely related to plant colonization,survival,growth and death,and these attributes can significantly affect ecosystem function and reflect the response of vegetation to environmental changes.In this study,the method of"space instead of time"was adopted in the stone desert area of karst plateau,and five stages of plant communities were selected as research objects:herbaceous community stage,grass-shrub transitional community stage,shrub-shrub stage,shrub-shrub stage and Arbor stage.Firstly,the adaptive functional characters of dominant species in different succession stages in stone desert region of karst plateau were studied,the average characteristics of communities were calculated respectively,and the communities in five succession stages were compared longitudinally.The differences of leaf functional characters in different succession stages in stone desert region of karst plateau were revealed.Secondly,taking the leaves of dominant plant species in each stage as the object,the relationship between leaf morphological and functional characters and water-holding function was studied.Finally,the ecological and economic functions of dominant tree species in different succession stages in the stone desert area of karst plateau were comprehensively evaluated,and the eco-economic function groups of tree species were divided.The main conclusions are as follows:The main results are as follows:?1?in this study,38 community plots in rocky desertification area of karst plateau were divided into 10 types by using bi-directional indicator species classification?TWINSPAN?and canonical correspondence analysis?CCA?,including 5 succession stages?herbaceous stage,grass irrigation stage,shrub stage,tree shrub stage and Arbor forest stage?.Among them,the dominant environmental factor for grassland is altitude,slope and rock exposed rate are the dominant environmental factors for grass shrub,shrub and tree community,and at the tree stage,soil type and slope direction are the environmental factors that determine the distribution of tree community.?2?there are great differences in unified characters among different species,and the characters are weighed against each other.The ratio of leaf length to width is 1.56-123.86,the leaf area is1.68-374.38 cm²,the specific leaf area is 28.68-301.12 6cm²·g^-1,the leaf dry matter content is0.19-0.77 g·g^-1,the leaf thickness is 0.43-2.17mm,and the leaf tissue density is 0.003-0.044g·cm^-3,chlorophyll Spad value 23.5-53.31.The functional characters of leaves of the same species changed with the process of vegetation restoration.The ratio of leaf length to width was positively correlated with leaf dry matter content and leaf tissue density?P<0.05?,and negatively correlated with leaf thickness and specific leaf area?P<0.01?.There was a very significant positive correlation between leaf area and leaf thickness?P<0.01?,but a significant negative correlation between leaf area and leaf dry matter content and leaf tissue density?P<0.05?.There was a significant negative correlation between leaf thickness and leaf dry matter content,specific leaf area,leaf tissue density and chlorophyll?P<0.05?.Leaf dry matter content was significantly negatively correlated with specific leaf area?P<0.01?,but positively correlated with leaf tissue density?P<0.05?.There was a very significant negative correlation between specific leaf area and leaf tissue density?P<0.01?,and a significant positive correlation between leaf tissue density and chlorophyll?P<0.05?.This shows that in the stage of vegetation succession,the adaptation of the community to environmental factors focuses on the leaf functional characters of the dominant species,and the leaf functional traits change in order to adapt to different environments.There was assimilation between leaf morphological and physiological traits.?3?Through the grey correlation analysis,altitude has the greatest influence on leaf thickness,leaf dry matter content,specific leaf area,leaf tissue density and chlorophyll,and slope direction has the greatest influence on leaf length-width ratio and leaf area.The functional characters of herbaceous stage were significantly different from those of the other four succession stages,and the ratio of leaf length to width,leaf tissue density and leaf dry matter content decreased with the succession.Leaf area,specific leaf area and leaf thickness showed an overall upward trend,and the order of chlorophyll in succession was grass shrub>Arbor>shrub>Arbor shrub>herb.?4?By means of PCA analysis and cluster analysis,the dominant tree species in the stone desert area of Karst Plateau were divided into 6 leaf water holding function groups.That is,large narrow leaves with high roughness and high water holding function group?WH-PFGs??,middle leaves with high roughness and high water holding function group?WH-PFGs??,leaflet narrow leaves with low roughness and low water holding function group?WH-PFGs??,middle leaf narrow leaves with high roughness and high water holding function group?WH-PFGs??,middle leaves with high roughness and high water holding function group?WH-PFGs??,leaflet with low roughness and low water holding function group?WH-PFGs??.The water-holding capacity of broad-leaved tree species is better than that of coniferous species in the rocky desertification area of karst plateau.There are mainly WH-PFGs?in herbaceous stage,WH-PFGs?,WH-PFGs?and WH-PFGs?in grass irrigation,shrub and Arbor irrigation stages,and WH-PFGs?,WH-PFGs?,WH-PFGs?,WH-PFGs?and WH-PFGs VI in Arbor stage.?5?The tree species were evaluated from the point of view of economic function,and the economic function groups of tree species were divided.The dominant tree species in different succession stages in rocky desertification area of karst plateau were divided into 6 functional groups.Medicinal-ornamental-industrial high economic function group?E-PFGs??,medicinal-ornamental high economic function group?E-PFGs??,ornamental medium economic function group?E-PFGs??,food-medicinal-ornamental-industrial high economic function group?E-PFGs??,medicinal-low economic function group?E-PFGs??,ornamental-industrial middle economic function group:?E-PFGs VI?.Herbaceous plants mainly increase roots,stems and leaves to obtain better medicinal economic value,shrubs get higher ornamental value through short stems,and trees get better economic value and ornamental value of wood mainly by increasing DBH and plant height.Among them,there are mainly E-PFGs?in herbaceous stage,E-PFGs?,E-PFGs?,E-PFGs?and E-PFGs?in grass irrigation and shrub stage,E-PFGs?,E-PFGs?and E-PFGs?in Arbor irrigation stage,and 6 economic functional groups in Arbor stage.This paper systematically studies the response of plant functional characters to the process of community restoration and the change law of eco-economic functional groups in karst forest.it has a certain guiding significance for the ecological control,ecological restoration and ecological environment construction and protection of karst rocky desertification.