Abstract: Taking three sandfixing plantations Hedysarum scoparium and Calligonum mongolicum, Haloxylon ammodendron- on the oasis verges in northeast Ulanbuhe desert irrigated by Huanghe River as test objects, the multi-species and multi-scale patterns and the species associations of the plantations were investigated by contiguous quadrats transects method, with the natural vegetation nearby as the control. The results showed that 74.29% of the natural vegetation was dominated by single species pattern of Artemisia ordosica, and 24.99% was dominated by single species pattern of Nitraria tangutorum. The sand-fixing plantations gradually became-close-to-natural vegetation. Compared with natural vegetation, the sandfixing plantations had higher pattern intensity, and played important role in sand-fixing and in accelerating the regeneration and succession of natural sand-fixing plants. However, with the succession, artificially planted shrubs would decline, while natural plants would be dominant. Therefore, it should be better to make use of the native dominated species in sand-fixing engineering. Under the almost same conditions, pattern scale was highly correlated with the characters and the associations of dominated species. The species association was correlated with the patch scale and species composition, as well as the species contribution to the patch.

Key words: swarming, behavioral ecology, Euphausia superba, swimming, physiological ecology