荒漠内陆河岸胡杨和多枝柽柳幼苗种群空间分布格局及种间关联性

Spatial distribution pattern and interspecific association of Populus euphratica and Tamarix ramosissima seedlings populations along desert inland river

运用方差均值比率法、负二项参数、丛生指标、平均拥挤度、聚块性指数和扩散系数等7个指标以及双项轨迹方差法,研究了塔里木河中下游荒漠河岸植被建群种胡杨(Populu seuphratica)和多枝柽柳(Tamarix ramosissima)幼苗种群的空间分布格局和种间关联性。结果表明,胡杨和多枝柽柳幼苗的空间分布呈显著的聚集分布,聚集规模大小为16m2。利用2×2列联表χ2统计量、联结系数和共同出现百分率等测度方法,综合分析了2个种对联结性质和程度。结果表明,胡杨和多枝柽柳2个幼苗种群表现出强的正关联,这2种植物种群现处于稳定分布格局,种间共存,占有共同的生态位。

In this paper, the methods such as V/m ratio t-test, negative binomial parameter, clump index, mean crowding intensity, index of patchiness, dispersion coefficient, and two-term local variance （TrLV） were used to analyze the spatial distribution pattern and interspecific association of Populus euphratica and Tamarix ramosissima seedlings populations in the middle and lower reaches of the Tarim River. The results showed that the spatial distribution pattern of the two populations all presented significantly aggregative at a block size of 16 m^2. Based on 2 × 2 contingency table, the interspecific associations of the two species were examined by means of χ^2- test, together with the association coefficient and percentage co-occurrence. The results indicated that the two species showed significantly positive association. It was suggested that the two populations in the study area were in stable distribution pattern, and the two species coexisted and held the common ecological niche.