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sur le développement des zones arides et semi-arides

Titre : Community Characteristics and Population Distribution Pattern of Agropyron Mongolicum in Desert Steppe in Heterogeneous Habitats

Auteur : 刘万龙

Grade : Master 2022

Université : Ningxia University

Résumé partiel
In order to understand the characteristics of Agropyron mongolicum community and its population spatial distribution pattern in desert steppe under heterogeneous habitat conditions,the species composition,diversity and community stability of Agropyron mongolicum community under different habitat conditions were studied in Dashuikeng Township（D）,Qingshan Township（Q）,Huamachi Township（H）and Gaoshawo Township（G）in Yanchi County,Ningxia.The niche and interspecific association of dominant species in Agropyron mongolicum community under heterogeneous habitat were quantitatively analyzed.At the same time,based on point pattern analysis,the spatial distribution pattern of Agropyron mongolicum population in heterogeneous habitats was discussed.The main results are as follows:There were 22 species of plants in 4 different habitats,belonging to 7 families.Among them,the average height,total coverage and aboveground biomass of Agropyron mongolicum community were the highest in Dashuikeng Township.The diversity of Agropyron mongolicum community in Huamachi Township was the highest.The community stability was highest in Dashuikeng Township and lowest in Gaoshawo Township.The niche width of Agropyron mongolicum was the largest in the 4 different habitats.As the dominant species in each habitat community,it had low niche similarity with other species.The overall correlation intensity of dominant plants in Dashuikeng Township,Qingshan Township and Huamachi Township showed significant positive correlation,while Gaoshawo Township showed no significant negative correlation.In Qingshan Township and Gaoshawo Township,the density of Agropyron mongolicum was higher,and it was dominated by small clumps of grade Ⅰ.In Dashuikeng Township,the proportion of grade Ⅱplant clusters of Agropyron mongolicum was the highest,and the density of plant clusters was small.The class Ⅰ clumps of Agropyron mongolicum in each habitat community showed aggregation distribution in different scales.With the increase of the scale,the grade Ⅱ clumps gradually changed from aggregation distribution to random distribution and uniform distribution.Grade Ⅲ and Ⅳ clumps were mainly randomly distributed.There was negative correlation or no correlation between grade I plant cluster wirh grade Ⅱ,Ⅲ and Ⅳ plant cluster in different scales.There was no correlation among grade Ⅱ,Ⅲ and Ⅳ clumps within the scale of this study.In the habitat community of Dashuikeng Township,the populations of Agropyron mongolicum and Stipa bungeana showed negative correlation in the scale range of 0-0.3m,and no correlation in other scales.In the habitat community of Gaoshawo Township,there was a positive correlation between Agropyron mongolicum population and Lespedeza potaninii population in the scale range of 0.6-1.7m,and there was no correlation in other scales

Mots clés : Desert steppe ;Agropyron mongolicum ;Community characteristics ;Niche;Spatial pattern ;

Présentation (CNKI)