疏勒河流域植被覆盖及植物群落多样性空间分布

Vegetation coverage and community diversity spatial distuibution in Shule River Basin

基于MODIS数据的植被覆盖分析表明疏勒河流域以覆盖度5%～25%的荒漠景观为主,覆盖度0～5%的戈壁和25%～50%的荒漠绿洲过渡带为辅.在中下游走廊平原区布设203个植物样方对研究区荒漠及荒漠绿洲过渡带的植物群落组成、结构和分布进行研究,共发现样方内植物97种,隶属于24科69属,其中菊科、豆科、藜科和禾本科最多,分别占物种总数的17.53%、16.49%、15.46%、13.40%;出现频率达10%以上的物种有5个,分别为芦苇(39.41%)、黑果枸杞(33.99%)、骆驼刺(32.51%)、多枝柽柳(20.69%)和白刺(12.32%),重要值依次为38.62%、26.06%、37.42%、34.66%、28.43%;经PC-ORD聚类分析,在欧氏距离200处可将研究区内的植被类型划分为8种,且植被类型随生境地貌不同而不同.综合运用5种多样性指数对植物群落多样性的分析表明:研究区植物群落结构极其简单,物种丰富度和均匀性较差,生态优势度较高,优势种的优势地位突出.

An analysis of vegetation coverage based on MODIS data showed that desert with a vegetation coverage of 5% to 25% was the most prominent part of the landscape in Shule River Basin, while gobi（0-5%） and desert-oasis ecotone（25%-50%） secondary. Through 203 sample sites, the vegetation community composition, structure and distribution in middle and downstream of the Shule River Basin were studied. 97 species, belonging to 24 families and 69 genera, were found from these plant samples. Compositae which made up of 17.53% of the total number of the species were the dominant group, followed by Leguminosae（16.49%）, Chenopodiaceae（15.46%） and Gramineae（13.40%）. There were 5 species whose frequency were more than 10%, i.e. Phragmites australis, Lycium ruthenicum,Alhagi sparsifolia, Tamarix ramosissima and Nitraria tangutorum, and their frequencies were 39.41%,33.99%, 32.51%, 20.69%, and 12.32%, respectively and important value were 38.62%, 26.06%, 37.42%,34.66% and 28.43%, respectively. A clustering analysis with PC-ORD showed that the vegetation types in our study area could be divided into 8 kinds when the Euclidean distance was 200, and the vegetation types were different with different landforms and habitats. Five kinds of diversity index were used to analyze the vegetation community diversity and the results showed that the structure of vegetation community in the study area was extremely simple while the species richness and uniformity was poor, and there existed a high degree of ecological dominance and the dominant species occupied an obvious superior position.