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Beijing Forestry University (2015)

Study on the Distribution and Hydrological Characteristics of Biological Soil Crusts in Different Desertification Ecosystem Areas

李柏;

Titre : Study on the Distribution and Hydrological Characteristics of Biological Soil Crusts in Different Desertification Ecosystem Areas

Auteur : 李柏;

Grade : Doctoral Dissertation 2015

Université : Beijing Forestry University

Résumé
Biological soil crusts serve as a vanguard for improving the ecological environment in arid, semi-arid desertification areas. It is a good indicator of the improvement status which the local ecological environment is undertaking. In desert areas, water condition is a key factor to restrict the ecological environment. Biological crusts play an important role in local vegetation succession due to their abilities to conserve and maintain moisture as their chief ecological protection functions. This study was completed in Yanchi, Gaoshawo in Ningxia Hui Autonomous Region and Dengkou in the Inner Mongolia Autonomous Region from 2010 to 2013. Through field investigation and laboratory experiment, vegetation community characteristics and diversity in desert areas were researched, and characteristics of biological crust thickness stage were analyzed by measuring chemical properties of biological crusts and the lower soil, and then effects of biological soil crusts on water infiltration and evaporation were reached to find the relationship between vascular vegetations and biological soil crusts in desertification area. The major results show that :(1) Study on biodiversity in different desertification ecosystem areas results show that:In Mu Us Desert, there were 13 plant species which belong to 6 families and 11 generas. Artemisia ordosica was the dominant species in Artemisia ordosica communities. Hedysarum Scoparium and Hedysarum Mongolicum were the dominant species in Hedysarum Scoparium and Hedysarum Mongolicum communities, respectively. Species composition and diversity characteristics of Artemisia ordosica communities were better than Hedysarum Scoparium and Hedysarum Mongolicum communities’. The dominant communities were Artemisia ordosica communities in local area.In Ulan Buh Desert, there were 12 plant species which belong to 7 families and 11 generas. Artemisia ordosica was the dominant species in Artemisia ordosica communities. Tamarix chinensis was the dominant species in Tamarix chinensis communities. The species composition and diversity characteristics of Tamarix chinensis communities were better than Artemisia ordosica communities’. The Artemisia ordosica communities were gradually to the Tamarix chinensis communities succession in local area.(2) Study on the distributionof biological soil crusts in different desertification ecosystem areas results show that:In Mu Us Desert and Ulan Buh Desert, biological soil crusts types can be divided into algae, lichen and moss crusts. The dominant species were Microcoleus vaginatus, Collema tenax and Byum argenteum, respectively. In Mu Us Dssert, the dominant species in plant cover and the community both were the lichen crusts in Mu Us Desert ; And in Ulan Buh Desert, the dominant species were linchen crusts and algae crusts in plant cover and community, respectively. Biological crust thickness decreases with increasing distance roots. The biological soil crust thickness distribution is associated with the crown of plants in different directions. Perennial dominant wind direction significantly influenced the distribution of biological crust thickness. Comparing two kinds of desert ecosystem, the coverage and thickness of the biological soil crust in Mu Us Desert were thicker.(3) Study on the physicochemical propertiesof biological soil crusts in different desertification ecosystem areas results show that:The relationship among biological soil crusts biomass was manifested as the biological soil crusts biomass of advantage communities was greater in a different desertification ecosystem. Because rain is rich in Yanchi, biological soil crusts biomass was bigger than Dengkou. Compared withalgae and lichen crusts, moss crusts had better bulk density and natural moisture content.The mechanical components were given priority to with sticky powder. The pH value of moss crusts were smaller and the organic matter, total nitrogen, available nutrient contents were higher

Mots clés : Biological soil crusts; Water infiltration; Water evaporation; Desertification ecosystern areas; Vegetational type;

Présentation (CNKI)

Page publiée le 5 octobre 2017