辽河平原北部草地类型特征及分布现状

为掌握辽宁省北部草地现状及群落特征，以辽河平原北部的彰武、康平、昌图、法库4县确权草地为范围，通过2年的野外详查，分析草地植被特征，并重新划分草地类型，运用ArcGIS 10.0软件勾绘出草地分布图。结果显示：25个调查样地共出现164种植物，隶属46科129属。根据水热、地形及植物群落结构特征，将调查区草地划分为疏林草地类、暖性灌草丛类和低平地草甸类3大类。其中，疏林草地类所含物种数最丰富，占到了总物种数的71.3%；疏林草地类和暖性灌草丛类以旱生植物为主，低平地草甸类湿生和水生植物相对较多。3类草地共出现8个草地型，疏林草地类2个，暖性灌草丛类3个，低平地草甸类3个，且均有乔木和灌木。与80年代相比，披碱草（Elymus dahuricus）、野古草（Arundinella anomala）、荻（Triarrhena sacchariflora）等中生植物占优势的草地型已消失，糙隐子草（Cleistogenes squarrosa）、冷蒿（Artemisia frigida）等旱生植物的优势度有所增加，典型草原旱生植物分布区向东扩展。3类草地的分布具有明显的区域性差异：彰武县以疏林草地类为主，昌图县以暖性灌草丛类为主，而康平和法库县则以低平地草甸类为主。4县共出现草地斑块11 250块，其中50亩以下的占81.2%，100亩以上的仅占8.8%，草地分布零散而面积小。

Characteristics and Distribution Situation of Grassland Types in Northern Liaohe River Plain

In order to know the present grassland situation and community characteristics of northern in Liaoning Province, the grasslands in the four counties, Zhangwu, Kangping, Changtu, and Faku in the north of Liaohe River Plain were investigated. The characteristics of grassland plant communities were analyzed, and the grassland types were re-classified and the grassland distribution map was plotted with ArcGIS 10 software through two years of field surveys. The results showed that there are 164 species of plants in 25 sample plots belonging to 46 families and 129 genera. According to the characteristics of hydrothermal, topographic and plant community structure, the grasslands in the survey area were divided into three categories:sparse forest grassland class, warm shrub grassland class and lowland grassland class. Among them, the number of species contained in the sparse forest grassland is the most, accounting for 71.3 percent of the total species. The shrub grassland and warm shrub classes are mainly drought-bearing plants, while lowland grassland class has more wet and aquatic plants. There are 8 grassland types for the 3 grassland classes, including 2 for sparse forest class, 3 for shrub grassland class, and 3 for lowland grassland class. Compared with the 1980s, the dominant grassland types with Elymus dahuricus, Arundinella anomala, Triarrhena sacchariflora have disappeared, and the dominance of xerophilous plants such as Cleistogenes squarrosa and Artemisia frigida have increased. The typical grassland xerophyte distribution area extends eastward. The distribution of the three types of grassland has obvious regional differences:Zhangwu County is dominated by sparse forest grassland class, Changtu County is dominated by warm shrub grassland class, and Kangping and Faku County are dominated by lowland grassland class. There are 11 250 grassland patches in the study area, 81.2 percent were below 50 mu, and only 8.8 percent were over 100 mu. The distribution of grassland was scattered and small.