Abstract: By using Shannon-Wiener index of niche breadth and Pianka index of niche overlap, this paper studied the niche characteristics of main plant species at different succession stages of vegetation in desert areas of north Gulang County, Gansu Province. The results showed that on mobile sand, Hedysarum scoparium had the widest niche breadth, followed by Artemisia arenaria. On semi-fixed sand, Nitraria tangutorum had the widest niche breadth, while on fixed sand, whether on unclosing fixed sand or on closing fixed sand, the niche breadth of H. scoparium was the widest. The niche breadth of the same plant species varied with vegetation succession stage, which reflected the effect of restored vegetation under different succession stages. Dominant species and the species with wide niche breadth had large niche overlap, while the niche overlaps of the same pair of species at different vegetation succession stages were inconsistent. Because of the habitat patch of species distribution, some species with narrow niche breadth also had large niche overlap.

Key words: Macrophytes, Community pattern, Semivariogram, Fractal theory