不同生境条件下泡泡刺(Nitraria sphaerocarpa)种群的空间格局及动态分析

Spatial Pattern of Nitraria sphaerocarpa Population and Dynamics in Different Habitats

应用生态空间理论(theoryofspatialecology)和地统计技术,分析了不同生境条件下泡泡刺种群的空间分布特征及其动态。结果表明:受气候条件的控制,泡泡刺种群是以斑块状格局形式存在。在较小的尺度上,生境条件起到了明显的作用,戈壁生境中的泡泡刺灌丛沙堆趋向于斑块小、密度大、空间自相关距离短,而沙漠生境中的结果相反。另外,沙埋和地下水位下降不仅为泡泡刺种群拓宽了生态位,而且是该种群演化的驱动力。

The theory of spatial ecology and geostatistics techniques are used to study the spatial pattern of Nitraria sphaerocarpa population and its dynamics in the different habitats. The results show that Nitraria sphaerocarpa population appears patch distribution and it is controlled by climate condition at the larger scales. But at the smaller scales, habitat conditions have significant impact on its spatial distribution. For example, the characteristics of Nitraria sphaerocarpa population on the Gobi desert are smaller patch, larger density and shorter distance of spatial autocorrelation, but that on sand habitat are contrary. Additionally, shrub dunes of Nitraria sphaerocarpa are generally formed through four accesses: seed germination, sucker propagation, larger patch falling into pieces and smaller patch combining through sand-bury. Sand-bury and groundwater decreasing not only broaden the ecological niche of Nitraria sphaerocarpa population, but also are the driving-force of the population dynamic.