A Study On Aboveground Biomass Of Woody Plant Community In Urat Region

The principles and methods of plant ecology are used to conduct field investigation and sample collection on the woody plant community in Urad.Through the identification of indoor plant specimens,the drying determination of biomass samples and data analysis,the purpose of this thesis is to analyze and discuss the composition of regional vegetation species and their characteristics.The characteristics,main woody plant community types and the aboveground biomass distribution of dominant woody plants provide data reference for the protection and rational utilization of plant resources in this region.The conclusion are shown as below:(1)There are 28 community types in the Urat area,and the woody plant community accounts for 75%of the total community,including 21 species of single-excellent community and 10 species of total-optimal community.The main communities are Reaumuria soongarica and Salsola passerina.Herbaceous community accounted for 25%of the total community,among which Stipa breviflora and Stipa capillata were the main communities.(2)There are 178 species of wild plants in the woody community,belonging to 31 families and 99 genera.Among them,there are 50 species of wild woody plants,belonging to 11 families and 29 genera,mainly Leguminosae,Chenopodiaceae,Compositae and Zygophyllaceae,and their life forms are mainly shrubs and semi-shrubs,occupying a total of 21.34%.There are 128 species of wild herbs,belonging to 20 families and 70 genera.The main species are Gramineae,Compositae,Leguminosae and Chenopodiaceae.The life forms are mainly perennial herbs,accounting for50%of them.There are 4 species of national rare and endangered protected plants.(3)There are 21 dominant species of woody plants in the Urat area,mainly Chenopodiaceae,Zygophyllaceae,and Leguminosae species.According to life forms,there are 9 species of shrubs,5 species of small shrubs,and 7 species of semi-shrubs.Among them,the most widely distributed shrubs are Nitraria sphaerocarpa,the small shrubs are Reaumuria soongarica,and the semi-shrubs are Salsola passerina.(4)The size and distribution of biomass of woody plants are closely related to their own growth conditions and environment.Affected by drought stress and human activities,there were significant differences in the above-ground biomass per plant,population above-ground biomass and community above-ground biomass in some plant species.The aboveground biomass per plant of dominant woody plants varies from 0.93g/plant to33487.39g/plant,among them,the largest shrub is Haloxylon ammodendron,and the largest small shrub is Artemisia ordosica,the largest semi-shrubs is Sympegma regelii.The aboveground biomass of the populations ranged from2.19kg/hm~2to 4985.95kg/hm~2,among them,the largest shrub is Haloxylon ammodendron,and the largest small shrub is Artemisia ordosica,the largest semi-shrubs are Salsola passerina and Convolvulus gortschakovii.The variation range of aboveground biomass of the community was2.19-7843.39kg/hm~2,among them,the largest shrub community is Haloxylon ammodendron,and the largest small shrub community is Artemisia ordosica,the largest semi-shrubs community is Salsola passerina.(5)The water ecological types of woody plants are mainly ultra-xerophyte and xerophyte woody plants,so with the decrease of longitude,the biomass of shrubs increases,and the biomass of semi-shrubs decreases,the land desertification is serious,and the environment becomes more and more serious.Drier.With the decrease of longitude,the species of woody plants continued to increase,and the community structure became more and more complicated.The community types from west to east are shrubs,semi-shrubs-small shrubs,and shrubs-small shrubs.With the decrease of latitude,the species of woody plants continued to decrease,and the community structure became single.The community type of woody plant and the distribution of aboveground biomass are indirectly affected by soil type.The vegetation types on desert sandy soil are mainly shrubs and small shrubs,and the vegetation types on light brown soil are mainly semi-shrubs and small semi-shrubs.Therefore,the desert sandy soil has the highest productivity,and the above-ground biomass decreases continuously from west to east.(6)The regional zonality of community types and above-ground biomass in the Urat area is obvious,and the phenomenon of shrubbery is becoming more and more common.The west,middle and south are desert areas,and the east and north are steppe desert areas.Among them,the aboveground biomass in the desert area is dominated by Haloxylon ammodendron,Caragana brachypod,Caragana korshinskii,Zygophyllum xanthoxylon and Artemisia ordosica.The aboveground biomass of a single plant in the steppe desert area is dominated by Haloxylon ammodendron,Artemisia ordosica,Nitraria tangutorum,Caragana korshinskii and Salsola passerina.The aboveground biomass of the population and community was dominated by Haloxylon ammodendron,Caragana tibetica,Reaumuria soongarica,Salsola passerina,Nitraria tangutorum.(7)There is competition or symbiosis in the community,competing for limited survival resources,In the communities of Zygophyllum xanthoxylon+Krascheninnikovia ceratoides,Krascheninnikovia ceratoides,Convolvulus gortschakovii,Caragana tibetica+Caragana tibetic,the plant height,coverage of woody plant companion species were positively correlated with aboveground biomass.the plant height and coverage of the associated species can promote their aboveground biomass.The plant height and density of associated woody plant species were negatively correlated with aboveground biomass in the communities of Salsola passerina+Reaumuria soongarica and Nitraria sphaerocarpa.the plant height and density of associated species have inhibitory effects on their aboveground biomass.(8)Through correlation analysis,the best independent variables were selected from five variables,namely plant height(H),crown length axis(L),crown width short axis(W),density(ρ),and coverage(C).Individual plant,population and community aboveground biomass models were established for21 dominant woody plants.In the single plant aboveground biomass model,the best independent variable is W,and there are 7 species;in the population aboveground biomass model and the single-optimal community aboveground biomass model,the best independent variable is C,which are 10 species;in the aboveground biomass model of the co-optimal community,the best independent variable is H,and there are 7 species.the prediction model for the aboveground biomass of a single shrub is a power function equation,and there are 10;the prediction model for the above-ground biomass of population is a polynomial equation,and there are 7;in the single-excellent species community,the prediction model The models are logarithmic function equations,polynomial function equations and one-variable linear equations,all of which are 4.In the common elite species community,the prediction model is one-variable linear equations,and there are 7 models.