呼伦贝尔草原风蚀坑及下风侧积沙区植被小群落特征

Micro-community characteristics of vegetations in blowouts and depositional areas of Hulunbuir grassland,Inner Mongolia.

采用传统样方法,调查了呼伦贝尔草原固定风蚀坑、半裸露风蚀坑和裸露风蚀坑及其积沙区的植被小群落,并对野外数据进行了统计学分析.结果表明:3种风蚀坑及积沙区植被小群落盖度都小于原生植被大针茅群系盖度,并随着固定风蚀坑、半裸露风蚀坑、裸露风蚀坑的顺序依次下降.固定风蚀坑小群落由无茎委陵菜和糙隐子草占优势,分盖度为5%.半裸露风蚀坑中未被风蚀区小群落以无茎委陵菜和苔草占优势,分盖度为2%;积沙区小群落以无茎委陵菜、冰草、糙隐子草和百里香占优势,分盖度为4%.裸露风蚀坑无植被或仅西南坡出现沙蓬占优势的小群落.裸露风蚀坑积沙区中部以沙蓬占优势,分盖度为4.7%;在其边缘沿顺风向依次以冰草(2.7%)、苔草(2.6%)和百里香(1.7%)占优势.物种重要值平均值在固定风蚀坑、半裸露风蚀坑和裸露风蚀坑分别为12.64%、13.38%和20.08%,在半裸露风蚀坑积沙区、裸露风蚀坑积沙区中部和边缘分别为12.55%、40.48%和11.15%.

By using traditional sampling methods, the micro-communities of vegetations in fixed, semi-bare, and bare blowouts of Hulunbuir grassland were investigated, and the investigation data were statistical analyzed. The results showed that the vegetation coverage decreased in the order of fixed blowout, semi-bare blowout, and bare blowout, and was lower than that of the primary vegetation Form. Stipa grandis. PotentiUa acaulis and Kengia squarrosa were the dominant species in fixed blowout, with the coverage being 5 % ; while P. acaulis and Carex sp. were the dominant species in semi-bare blowout, with the coverage being 2%. The dominant species in depositional areas of semi-bare blowout were P. acaulis, K. squarrosa, Agropyron cristatum, and Thymus mongolicus, and the coverage was 4%. The dominant species on the southwest slope of bare blowout was Agriophyllum pungens. The middle depositional area of bare blowout was also occupied by A. pungens （ coverage 4.7% ）, and the edge of it was dominated by A. cristatum （ coverage 2.7% ）, Carex sp. （ coverage 2.6% ） , and T. mongolicus （ coverage 1.7% ） from the edge of the depositional area to primary grassland. The mean species importance value in fixed, semi-bare, and bare blowouts was 12.64%, 13.38%, and 20. 08%, while that in the depositional area of semi-bare blowout and in the middle and edge of bare blowout was 12.55%, 40. 18%, and 11.15%, respectively.