Abstract: A series of techniques including the analysis of variance, X²test and Ochia index were used together with a 2×2 contingency table in order to analyze the interspecific associations of dominant species of Carex lasiocarpa community in Sanjiang Plain in 1973, 1983 and 2003. The results indicated that with the process of succession, the association of species showed significantly positive correlation in each stage, and the sequence of association was in the order of 1983>1973>2003. The property of interspecific associations between the main species pairs, namely the proportion of positive and negative associations, remained unchanged. The proportion of the species pairs of significant association gradually increased; the association intensity of species pairs gradually strengthened. The association status or association degree of the same species pairs varied according to succession stage.

Key words: Nature reserve, Ecological security, Nature reserve network, Design