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Université de Mongolie-Intérieure (2017)

Study on the Community Characteristics and Geographic Distribution of Stipa Gobica Steppe in China

朱媛君;

Titre : Study on the Community Characteristics and Geographic Distribution of Stipa Gobica Steppe in China

Auteur : 朱媛君;

Grade : Master’s Theses 2017

Université : Université de Mongolie-Intérieure

Résumé
Stipa gobica is a perennial xeromorphic fasciculate small herb,belonging to the genus of Stipa and Sect.Smirnovia,and its floristic geographical element is Middle Asia element.Stipa gobica steppe mainly distributs on the rocky slopes or rocky hills of desert steppe region,and can also be found in rocky hills or mountains of the typical steppe area eastwardly and some rocky slopes of the desert region westwardly.Due to the almost coincident distribution range and similar morphological characteristics between Stipa gobica and Stipa klemenzii and the complete reversal of community type dominated by the two species in Chinese and Mongolica major works(mainly as a result of scientific name upside down),the community description about two species is incompatible with the actual.Thus,the systematic deep study on the plant community characteristics and geographic distribution of Stipa gobica steppe in China is helpful to distinguish the community features between the Stipa gobica steppe and Stipa klemenzii steppe,revise the confusion of major vegetation works and expand the research field of steppe vegetation ecology,which can provide scientific basis for establishing natural regionalization scheme reasonably,and also play an important role in vegetation conservation of desert steppe and reasonable arrangements for grazing and livestock production.Based on the systematical understanding of the community characteristic and spatial distribution of Stipa gobica steppe and the detailed investigation of 116 plots in Stipa gobica steppe,we obtained the following conclusions:1.The constructive species Stipa gobica had similar distribution range with Stipa klemenzii,but its morphological characteristics was more similar to Stipa tianschanica and showed greater difference with Stipa klemenzii.Stipa gobica and related species Stipa tianschanica have obvious differences in the length of glumes,lemma,awn,awn needle and the feature of whether the ring of short hairs existing in the apex lemma.Additionally,for the geographical distribution Stipa gobica also had a relatively independent distribution center compare to Stipa tianschanica,so we can concluded that there were multiple independent and discontinuous variation of morphological characteristics between Stipa gobica and Stipa tianschanica,and the two species separately had their own abundance distribution center,being in line with the concept"Morphology-biology Species",so they were independent species in morphological characteristics and geographic distribution.2.According to the quadrat data,303 seed plants belonging to 40 families and 139 genera(including the subspecies,varieties and forms)were recorded in the Stipa gobica steppe of China,Among which there were 5 gymnosperm species belonging to 2 families and 2 genera,and 298 angiosperm species belonging to 38 families 137 genera and.The families having more than 10 species were Compositae,Gramineae,Leguminosae,Rosaceae,Liliaceae,Chenopodiaceae and Caryophyllaceae respectively.Hemicryptophyte,a total of 189 species is the dominant life form in Stipa gobica steppe,which accounted for 62.38%of the total species.As for the ecological type of water,xerophytes was the dominant plants,with a total of 127 species,accounting for 41.91%of all species.Middle Asia element(included the variants)areal-type(including 63 plant species)was the major floristic elements,containing 31.35%of the total species.The cover of 0.1%-1%was the dominant level in the cover class distribution of the species,including 64.1%of the total of the species ;The constancy degree of I(0%-20%)was the dominant level in the constancy degree distribution of the species in Stipa gobica steppe,containing 94.87%of the all species.3.In accordance with the classification principle of community-appearance,

Mots clés : Stipa gobica steppe; community characteristics; floristic geographic elements; community diversity; soil microelement;

Présentation (CNKI)

Page publiée le 13 février 2018