宁夏盐池荒漠草原植物的生态位研究

Niche characteristics of desertification grassland in Yanchi County of Ningxia Province

为了揭示宁夏荒漠草原的植被特征及生长状况,运用Levins生态位宽度指数及Pianka生态位重叠指数,在宁夏盐池县吴纪圈对荒漠草原植物的生态位进行了计测.结果表明:2010年达乌里胡枝子、丝叶山苦荬的生态位宽度值最大,是该区的优势种;2011年,由于种间竞争、降水量等因素的影响,该区的优势种是达乌里胡枝子、阿尔泰狗娃花、丝叶山苦荬.2010和2011年的生态位重叠度结果均表明,在荒漠草原生态位宽度大的物种与其他物种的重叠度指数不一定大,即较大的生态位宽度和较大的生态位重叠度之间并无直接的线性关系.与2010年相比,2011年7～8月降水量较大,植物长势好,生态位宽度和生态位重叠度总体比2010年大.可见,在西北荒漠草原区,生长季的降水量可在很大程度上决定植被生长状况.

In order to reveal the characteristics and growth of plants in desertification grassland in Ningxia, the niche breadth and niche overlapping of plants in the desertification grassland of Wujijuan, Yan- chi county were measured by means of Levin＇s niche breadth and Pianka niche overlapping indexes. The re- sults showed that Lespedeza dazzurica and Laceris chinensis var. graminifolia had the widest niche breadth, and were the dominant species in 2010 in this region. In 2011 ,Lespedeza davurica, Heteropappus altaicus and Lereris chinensis var. grarninifolia became the dominant species because of the interspecific competition and rainfall and so on. Meanwhile, the results of niche overlapping in 2010 and 2011 showed that the species with wide niche breadth did not always have wide niche overlapping,and the niche breadth and niche overlapping did not show an obvious linear relation. Compared with 2010, the niche breadth and niche overlapping were wider on the whole in 2011, because the amount of the rainfall from July to August was much more than that in 2010, the plants grew better. The results above indicated that the amolmt nf rainfall in th ;