关键词: 小叶锦鸡儿, 灌丛特征, 发育规律, 积雪形态, 阻雪模型

Abstract: In grasslands, livestock often concentrate in the vicinity of water point due to watering demands, which generates piosphere. We set 6 sampling distances (50, 100, 200, 400, 800 and 1200 m) from an artificial water point in the Junggar Basin, Xinjiang, and collected soil samples to investigate the soil seed bank. Our analysis showed that there were 17 species belonging to 8 families in the soil seed bank. The species were mainly from Compositae and Chenopodiaceae. The numbers of annual herbs and perennial herbs were 10 and 7 respectively. The soil seed bank density was 211.5-362.5 seeds·m^-2, and the lowest density of soil seed bank was found in the closest vicinity of the water point (50 m), while the highest was observed in the farthest area (1200 m). The species number of the soil seed bank significantly decreased (P<0.01) with distance from water point; the percentage of the annual herbs increased, while the percentage of the perennial herbs decreased. The similarity indexes of the soil seed bank between every two adjacent sampling points were 0.70-0.84, displaying small spatial heterogeneity. The Shannon, Margalef and Pielou indexes of soil seed bank decreased with distance from water point. These results suggested that the number of plant species in soil seed bank was increased by piosphere effect. Consequently, the number of constructive species seeds decreased, while the number of ephemeral and ephemeroid plant seeds increased.

Key words: snow morphology, shrub characteristics, Caragana microphylla, counteracting snow movement model., development pattern