宁夏盐池不同封育措施下的植物生态位研究

运用Levins生态位宽度指数及Pianka生态位重叠指数,对宁夏盐池柳林堡人工封育草场不同措施（老封育区、新封育区、对照区）下的植物生态位宽度及生态位重叠度进行计算,从生态位角度揭示不同措施下的植被恢复情况。结果表明：老封育区、新封育区和对照区的主要建群种生态位宽度均有较大的差异,老封育区宽度值最大的是耐旱性极强的阿尔泰狗哇花（Heteropappus altaicus（Willd.）Novopokr.）、丝叶山苦荬（Lxeris chinensis var.graminifolia（Ledeb.）H.C.Fu）、叉枝鸦葱（Scorzonera divaricata Turcz.）,说明随着封育时间的延长,封育区植被有旱生化方向发展的趋势;新封育区的优势种是丝叶山苦荬、黑沙蒿（Artemisia ordosica Krasch.）、苦豆子（Sophora alopecuroides）、刺沙蓬（S.ruthenica Iljin）,且4种植物生态位宽度接近,对资源环境的利用更为均衡;对照区的优势种是黑沙蒿、苦豆子、刺沙蓬,宽度值分别为0.729、0.666、0.540。同时,3种措施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度之间并不存在直接的线性关系。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。

Vegetable niche of different enclosure measures in Yanchi county,Ningxia

In order to show restoration of vegetation under different measures from niche＇s view,the niche breadth and niche over-lapping under different measures（including old enclosed region,new enclosed region,contrast region）are measured by means of Levins niche breadth and Pianka niche overlapping indexes in the enclosed grassland of Liulinbao,Yanchi county,Ningxia.It shows that the niche breadth of dominant species are different obviously among old enclosed region,new enclosed region and contrast re-gion.The niche breadth of Heteropappus altaicus（Willd.）Novopokr,Lxeris chinensis var.graminifolia（Ledeb.）H.C.Fu,Scorzonera divaricata Turcz.which have strong drought tolerance is biggest in old enclosed region,and it indicates that the vegetation of en-closed region have drought biochemical development tendency with the extension of enclosure time.Lxeris chinensis var.graminifo-lia（Ledeb.）H.C.Fu,Artemisia ordosica Krasch.,Sophora alopecuroides and S.ruthenica Iljin are dominant species in new enclosed region,and these four plants have approximate niche breadth,which indicates that these four plants utilize the resources and envi-ronment more equally in new enclosed region.Artemisia ordosica Krasch.,Sophora alopecuroides,S.ruthenica Iljin are dominant species in contrast region,whose niche breadth is 0.729,0.666,0.540.Meanwhile,the result of niche overlapping of these three measures shows that the species with big niche breadth did not always have big niche overlapping,and the niche breadth and niche overlapping did not have a positive direct linear relation.It shows from another point of view that environment and resources have high spatial heterogeneity during the vegetation restoration process.