宁夏盐池荒漠化地区人工封育草场的植物生态位特征

Vegetable niche of enclosed desertification rangeland in Yanchi county, Ningxia

运用Levins生态宽度指数及Pianka生态位重叠指数,对宁夏盐池人工封育草原2006年和2007年植物生态位宽度及生态位重叠进行计量,以了解干旱半干旱区草原植物生态位格局。结果表明:2007年封育区植物种的生态位宽度及种间的生态位重叠指数总体上较2006年有所降低;2006年黑沙蒿生态位宽度最大,达0.768,是06年封育区的优势种;2007年封育区的优势种为刺沙蓬和黑沙蒿,其生态位宽度值分别为0.544、0.460;2006年和2007的生态位重叠结果均表明,生态位宽度大的物种不一定和其他物种有大的重叠指数,较高的生态位宽度和较高的生态位重叠之间并不存在直接的线性关系;2006年、2007年较高的Pianka生态位重叠指数都出现在生态位宽度较小的物种之间。这一现象从另外一个角度说明植被恢复过程中环境资源存在着高度的空间异质性。

In order to find the vegetable niche pattern in arid and semi-arid grassland region, the niche breadth and niche overlapping in Yanchi county of Ningxia in 2006 and 2007 are measured by means of Levins niche breadth and Pianka niche overlapping indexes in the enclosed grassland. It showed that the niche breadth and niche overlapping indexes of the enclosed grassland in 2007 are much lower than in 2006 as a whole; The niche breadth of Artemisia ordosica is bigger than other species in the region in 2002. In 2003, the dominant species were Artemisia ordosica and Salsola ruthenica. Their niche breadth indexes were 0.544 and 0.460 respectively. The results of niche overlapping in 2006 and 2007 also showed that the species with big niche breadth didn＇t always have big niche overlapping, and the niche breadth and niche overlapping did not have a positive direct linear relation. The higher Pianka niche overlapping in 2006 and 2007 both appeared in the species with low niche breadth, which showed from another point of view that environment and resources have high spatial heterogeneity during the vegetation restoration process.