Abstract: In this paper, 0-10 cm soil samples were collected four times (April, August and December of 2008, and May 2009) from five sites with plant communities at different succession stages in karst region of northwest Guizhou, and germinated in a greenhouse, aimed to understand the seasonal dynamics and strategies of the soil seed banks. In the soil seed banks, a total of 130 species were identified, and the seed density varied from 541 to 11180 ind·m^-2.Herbaceous plants seed density and species number were far greater than woody plants’, and sampling time and sites had significant effects on the mean values of the seed density and species number in the soil seed banks. At all five sites, the mean species number in the seed banks was the highest in April and the lowest in December, with an exception in grassland where the species number in soil seed bank was the lowest in August. The seed density peaked in April, and had no significant differences in August, December, and next May. The peaks of the seed density and species number in April could be due to the seed input/output pattern, which highly related to phenology, and to the persistence of seeds from previous years. Four seasonal soil seed bank strategies were identified, two transient and two persistent. Soil seed-bank strategy is a life-history trait of plant species, but the disturbance history and microenvironmental factors also have effects on the seasonal variations in seed quantity of some species.

Key words: Pinus koraiensis, Canopy patch, Spatial structure