内蒙古西鄂尔多斯沙冬青退化种群的空间格局及其与发育阶段的关联性

Spatial distribution patterns of Ammopiptanthus mongolicus degraded populations in relation to developmental stages in western Erdos of Inner Mongolia

以内蒙古西鄂尔多斯国家级自然保护区内沙冬青(Ammopiptanthus mongolicus)种群为对象,采用O-ring统计分析方法对不同衰退程度沙冬青种群的空间格局与发育阶段的关联性进行研究。结果表明:西鄂尔多斯不同衰退程度的沙冬青种群空间格局表现各异,与尺度大小有关;重度和中度衰退的沙冬青种群在0～50 m尺度下均表现为随机分布;轻度衰退沙冬青种群在小尺度表现为聚集分布,随尺度增加转变为随机分布;健康沙冬青种群在小尺度下表现为聚集分布,在中等尺度下表现为均匀分布,而在大尺度下表现为随机分布;不同发育阶段的沙冬青种群空间格局在不同尺度下表现不同;幼、老龄植株在0～50 m尺度下均表现为随机分布,中幼龄植株在中等尺度下表现为聚集分布,在其余尺度表现为随机分布,中龄、中老龄植株在小尺度下表现为聚集分布,随尺度增加表现为均匀分布,在大尺度下表现为随机分布;不同发育阶段沙冬青植株的关联性表现差异;在0～50 m尺度下幼龄植株与其余各发育阶段植株均无显著关联;从中幼龄级开始,随龄级增大,不同发育阶段植株之间开始表现出关联性,在大部分尺度上均呈正关联;但在小尺度(5 m)中龄与中老龄植株却呈负关联。

We examined the spatial distribution and associations of Ammopiptanthus mongolicus with different recession degrees and at different developmental stages in West Ordos National Nature Reserve in Inner Mongolia,China,with O-ring statistical analysis method. Spatial distribution patterns of A. mongolicus populations varied with different recession degrees,depending on the scale level. Populations with severe and moderate recession degrees performed random distribution at 0-50 m scale,while those with mild recession displayed clumped distribution,and shifted to random distribution with increasing scales. Healthy population showed clumped distribution at the small scale,uniform distribution at the middle scale,and random distribution at the large scale. Spatial distribution patterns of A. mongolicus varied with developmental stages. The population with young and old age classes displayed random distribution at the scale level of 0-50 m,whereas population with young-middle age class showed clumped distribution at the middle scale and random distribution at other scales. The populations with middle age class and middleold age class all showed clumped distribution at the small scale,but showed uniform distribution with increasing scale and random distribution at the large scale. Moreover,the spatial association of A. mongolicus varied with developmental stages. There was no correlation between the population at the young class and those at different developmental stages at 0-50 m scale. Beginning with the populations at the middle-young class,the associations started to appear with the increase of age class. There was a positive correlation between these high age classes at most scales,whereas there was a negative correlation between the populations of middle class and middle-old class at the 5 m scale.