Abstract: In 2005 and 2006, investigations were made on the soil seed bank, plant community composition, and vegetation density on a typical degraded grassland in Jinsha River dry-hot valley, which was enclosed in 2004, with the relations of soil seed bank with vegetations analyzed. The results showed that the density of soil seed bank was significantly positively correlated with the density of vegetations in the year of enclosure (P<0.01), and the regression equation could be well expressed by quadratic curve. The soil seed bank under Heteropogon contortus, Digitaria ciliaris, Bulbostylis densa, and Fimbristylis dichotoma populations had significant positive correlations with the vegetation density of the populations (P<0.01), while that under Pasdpalum paspalodes, Poa acroleuca, Arthraxon breviaristatus, Oxalis corniculata, Bidens pilosa, and Phyllanthus urinaria populations were not.

Key words: Sabina przewalskii community, Life form spectrum, Community structure, Forest-grass ecotone, Disturbance, Grazing