黄河源区山生柳灌丛草甸植物群落多样性及植物量组成

Study on the vegetation community diversity and the biomass composition of Salix oritrepha shrub meadow in the headwater area of Yellow River

对黄河源区山生柳灌丛草甸物种组成、结构及其植被生产力进行了调查。结果表明,该类植被由45种植物组成,隶属于14科33属。其中,灌木层由3种灌木组成,隶属于3属2科,优势度为：山生柳Salix oritrepha（57.28%）〉金露梅Potentilla fruticosa（28.19%）〉高山绣线菊Spiraea alpina（14.53%）。草本层由42种植物组成,隶属于13科31属,优势种为垂头菊Cremanthodium spp.、黄芪Astragalus spp.、线叶嵩草Kobresia capillifolia和小金莲花Trollius pumilus。草本层的Shannon-Wiener多样性指数为3.42,Simpson优势度指数为0.96,Pielous均匀度指数为0.92。群落地上干物质量为296.4 g/m^2,地下植物量为3185.6 g/m^2。地下植物量主要分布在0～10 cm土层,为2 272.0 g/m^2,占0～30 cm土层植物量的71.3%,根冠比为10.8。阔叶草类、莎草类和禾草类植物分别占总鲜质量的73.4%、20.1%和6.5%;占总干质量的57.1%、30.6%和12.3%。根据该灌丛物种、生产力构成及现状分析,黄河源区山生柳灌丛目前处于中度利用状态。

The species composition,structure and vegetation productivity of Salix oritrepha shrub meadow in the headwater area of Yellow River were studied.The results indicated： There were about 45 species,which belongs to 33 genera and 14 families in this community.In which,there were 3 shrubs,which belongs to 3 genera and 2 families in shrub layer.And the order of important value was： Salix oritrepha（57.28） 〉 Potentilla fruticosa（28.19） 〉 Spiraea alpina（14.53）.In which,there were 42 vegetations,which belongs to 31 genera and 13 families in the herbaceous layer.And the dominant species were Cremanthodium spp.,Astragalus spp.,Kobresia capillifolia and Trollius pumilus.The indices of Shannon-Wiener（H′）,the index of Simpson（D） and Pielous（J′） were 3.42,0.96 and 0.92 respectively.The dry above-ground biomass of community was 296.4 g/m^2 and the dry under-ground biomass was 3 185.6 g/m^2.The under-ground biomass mainly distributed within 0 to 10 cm of soil depth,which was 2 272.0 g/m^2 and accounted for 71.3% of biomass within 0 to 30 cm soil depth.The root-shoot ratio（R：S） was 10.8：1.The forbs genera,sedge genera and herbaceous genera accounted for 73.4%,20.1% and 6.5% of the total fresh biomass,and 57.1%,30.6% and 12.3% of the total dry biomass respectively.The result showed that the S.oritrepha shrub meadow was at the moderate level of grazing utilization.