裸沙斑块生境岛对沙米Agriophyllum squarrosum种群影响的研究

灰色关联度分析表明，裸沙斑块面积的变化对沙米种群结构、土壤水分和紧实度等有明显的影响，裸沙斑面积对种群结构的影响最高，平均关联度为０．７９；其中在沙米种群结构的所有指标中，沙米种群大小与裸沙斑面积的变化关联度最高为０．８４，种群密度随裸沙斑面积的变化最小，关联度为０．５９。

Study on Influence Upon Agriophyllum squarrosum Population by the Niche Island of Nude Sandy Patches

The results of gray correlative analysis have shown that the area change of nude sandy patch obviously effects the structure of annual plant Agriophyllum squarrosum population, soil moisture and soil hardness in its scopes. The relation between the patch area and the structure had the highest mean gray correlative degree as 0.79 among relations between the patch area, the soil moisture and hardness. Further, the population size had the highest the degree among all items of the structure; otherwise the population density had the lowest the degree as 0.59 among them. Meantime, the area change also influenced the soil moisture and hardness, the mean degrees were 0.62 and 0.57 respectively. The soil moisture positively correlated with the patch area and the hardness negatively correlated with the patch area. Biomass and its module varied less with the patch area change; their differentiation coefficients and gray correlative degrees fluctuated from 0.63 and 0.76 to 0.76 and 0.89, respectively.