The Study Of Soil Seed Bank At The Alpine Meadow On Easten Qinghai-Tibet Plateau

Seed banks are important in the long-term survival of individual species, as well as plant communities. A deal of studies of seed bank have examined in temperate zone. Few studies had examined seed banks in alpine communities, and little is known about the relationships between aboveground vegetations and seed banks. In order to understand and protect the pasture, we studied the persistent seed bank and plant community composition in both undamaged and degraded areas in different habitat on the eastern of the Qing-hai Tibet Plateau in china. The results showed:1. There were a total of 8254 seedlings recorded in the cumulate soil, which corresponded to overall seed density of 6785 seeds m2 and belonging to 78 species from 21 families in 10cm deep soil layer.2. The perennial species were most abundant species in the seed bank, which made up of 85% species in the seed bank, but the seedlings were made up 55% the seedlings of seed bank. On the contrary, the annual species was fewer in the seed bank, but the seedlings were made up 45% seedlings of the seed bank.3. Species relative abundances in the establishment vegetation and in the seed bank were not significantly correlated. The similarity in the undamaged meadows and the seed bank for each vegetation type is relatively low, with the average values was 40%, simultaneity The similarity was in increase with degradation, the average values was 62%. The DCA ordination results were shown vegetation plots and seed bank plots clearly difference of species composition, but the among seed bank plots was not shown significant difference.4. The size of seed bank was shown significant difference, but it's the difference of species composition was not shown significant difference.5. The degradation of meadoa has significant effect on seed bank, which the density was decrease with degradation. But the composition of species in seed bank was not showen significant difference. The diversity of seed bank also was dearease withdegradation. Degradation strongly influences the presence of tolerative species in the seed bank and the vegetation, but it were less role to ruderal species. The similarity was in increase with degradation, the average values were 50%.Our results suggest that: 1) early-successional species are well represented in the seed bank, 2) the shade-tolerant perennial are short of in the seed bank, 3) Grazing strongly influence the presence species of tolerative species in the seed bank and the vegetation, but it is less role to ruderal species, 4) the soil seed bank make important contributions to recovery in a sub-alpine meadow on the east part of the Tibet plateau.