Spatial-temporal Patterns Of Soil Seed Banks In The Successional Series Of Leymus Chinensis And Kalimeris Integrifolia In The Northeast Meadow

In this experiment, the seed banks among different succession stages of a serieswere researched, including Leymus chinensis community, Leymus chinensis+Kalimeris integrifolia community, Kalimeris integrifolia+Leymus chinensiscommunity and Kalimeris integrifolia community in Songnen Plains of China. Usingthe methods of field survey sampling and germinating, the composition, density,diversity index and its seasonal dynamics of the soil seed banks were analyzed fromMay to October in2011and2012, to understand soil seed bank in the dynamics ofvegetation succession and provide an important theoretical basis for the restoration ofdegraded meadow vegetation and scientific management. The results were as follows:（1）There were24species in the soil seed banks, belonging to10families and20genera, Gramineae were6species and accounted for25%、Legume were4speciesand accounted for16.67%、Chenopodiaceae were4species and accounted for16.67%、Compositae were3species and accounted for12.5%、Polygonaceae were2species and accounted for8.33%、Cyperaceae, Ranunculaceae, Liliaceae, Rosaceae,Lamiaceae respectively was1species and accounted for4.17%.（2）The soil seed bank density of four succession communities from thebeginning of the growing season to the end in two years were as follows. In K.integrifolia community, the seed density was the largest in May2011, the lowest inSeptember2012, and ranged from6490.0±7049.7to25440.0±16161.3grain/m~2. InK. integrifolia+L. chinensis community, the seed density was the largest in May2011, the lowest in August and October2012, and ranged from3990.0±3823.3to11660.0±4160.1grain/m~2.In L. chinensis+K. integrifolia community, the seeddensity was the largest in May2012, the lowest in September2012, and ranged from1430.0±1969.0to10300.0±7298.5grain/m~2. In L. chinensis community, the seeddensity was the largest in June2012, the lowest in August2012, and ranged from1290.0±1750.9to4780.0±3899.1grain/m~2.（3）In each month2011and2012, the seed density of K. integrifolia communitywas always higher than that of L. chinensis community in four successioncommunities. The density of L. chinensis community among each month of2011wasnot significantly different.（4）Seasonal variation in composition of soil seed bank was not significant in four succession communities.The seed banks of four communities had K. integrifoliaand Carex duriuscula in each month of2011and2012. The number of species was14,which existed both on aboveground vegetation and seed bank.（5）The seasonal dynamics of Shannon-Wiener diversity index exhibitedirregular fluctuation in seed banks of four communities. In each month2011and2012,the diversity index of L. chinensis community was always higher than that of K.integrifolia community. In K. integrifolia community, the index ranged from0.21to1.26. In K. integrifolia+L. chinensis community, it ranged from0.21to1.41. In L.chinensis+K. integrifolia community, it ranged from0.58to1.42. In L. chinensiscommunity, it ranged from1.03to1.76. Diversity index of L. chinensis communitywas always greater than1. Amplitude of variation was smaller than othercommunities. In four succession communities, the diversity index of seed bank wasgreater in July2011year than that of in July2012, and there was no significantdifference among other months of two years.