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Beijing Forestry University (2021)

Studies on the Dynamics of Wetland Plant Community,Ningxia Yanchi County,Semi-arid Regions of China

冯湘

Titre : Studies on the Dynamics of Wetland Plant Community,Ningxia Yanchi County,Semi-arid Regions of China

Auteur : 冯湘

Grade : Master 2021

Université : Beijing Forestry University

Résumé
Wetland in arid and semi-arid areas is one of the main wetland types in China,among which there are many marshes.However,due to the disturbance of climate change and human activities,the degradation of wetland in this area is serious.Therefore,the in-depth study of wetland water area and its vegetation changes are of great significance to the protection of water sources,species diversity in arid areas.By using the combined means of field investigation and positioning monitoring,this study analysis and calculation of vegetation community characteristics and wetland water area,explore the relationship between functional diversity index and traditional diversity index,explore the influence of wetland water area change on wetland vegetation,and analyze the community stability,which supplement and improve the results of wetland biodiversity research.This study found that :(1)Siertan wetland plant species is rich.Vegetation is sensitive to external disturbance because of its great annual variation in the fragile ecological environment.The species composition of Silertan wetland was mainly herbaceous vegetation,among which perennial herbaceous vegetation accounted for 62.14%.From the perspective of family flora,the flora of the study area was mainly distributed in the world,accounting for 56% of the total families.By using TWINSPAN quantitative classification method,combined with the field investigation in the study area,the vegetation community in the study area was divided into 12 association types.(2)Vegetation community diversity is rich in the study area.Correlation analysis of diversity index between the discovery showed that : Shannon Wiener diversity index and index of Patrick,Simspon Pielou,were significantly correlated on the confidence level of 0.05.Patrick and other index of correlation is not obvious.Correlation between functional diversity index showed that the functional richness FRic and functional dispersion FDis and rao’s quardratic entropy Rao Q were significant correlation on the confidence level of 0.01.There was no significant correlation between functional evenness and other indexes.Shannon-Wiener index was positively correlated with functional dispersion FDis(P<0.05) ;Simpson index was positively correlated with rao’s quardratic entropy Rao Q,but negatively correlated with functional evenness FEve.(3)The stability analysis of the vegetation community in different years in t that the wetland plant community was in an unstable state,and the stability was different among different he study area showed lines with great inter-annual fluctuations.The stability of the northern line was the best,which could resist a certain degree of drought.The western line was most affected by human activities,and the vegetation community composition was relatively simple and in an unstable state.The stability of the east line had the largest interannual variation and the community stability was poor.(4)The influence of wetland water area on plant community species was significantly correlated with species diversity and community stability(P<0.05).The water area of Siertan wetland was shrinking due to a combination of reduced rainfall and drought.At present,only in the years with heavy rainfall,there is a short clear water surface,and the phenomenon of salinization is prominent,and the community species spread to the center of the wetland.

Mots clés : Wetland ;Plant community ;Biodiversity;Community stability ;Water area ;

Présentation (CNKI)

Page publiée le 22 octobre 2022