Soil seed bank and its correlations with aboveground vegetation in ecological restoration zones of Wenchuan Earthquake Region

To determine the characteristics of soil seed banks and their relationships with aboveground vegetation in different climate zones, field surveys backed up with laboratory experiments were conducted in a typical ecological restoration zone in Weizhou Township (Wenchuan County) and Hanwang Township (Mianzhu City) of Sichuan Province. This zone was the epicenter of the massive Wenchuan Earthquake on May 12, 2008. We analyzed germination dynamics, quantity characteristics, species compositions, diversity characteristics and correlations with aboveground vegetation of soil seed bank in two climate areas (semi-arid dry warm river valley climate area, subtropical humid monsoon climate area) in ecological restoration zone of Wenchuan Earthquake Region. SBES (seed bank endemic species) and SAVS (seed bank aboveground vegetation species) were used as new indicators to describe the systematic process of soil SAVS system. The results suggested that while undestroyed sample plots had two germination peaks of seed bank, destroyed sample plots had only one germination peak. Seed banks in different climate areas had different germination potentials at different soil depths. The mean density of soil seed bank was 192?1 544 seeds·m^-2 and both the surface density and mean density of undestroy sample plots were greater than that in destruction sample plots. Also that in semi-arid dry warm river valley climate area was greater than that in subtropical humid monsoon climate area. A total of 50 species were identified in the soil seed bank using the germination method and herbaceous plants had the most significant advantage. Both the S?rensen and Jaccard similarity coefficients of species composition between soil seed bank and aboveground vegetation showed that HMD (destroyed sample plot in subtropical humid monsoon climate area) was greater than DHU (undestroyed sample plot in semi-arid dry warm river valley climate area), also greater than HMU (undestroyed sample plot in subtropical humid monsoon climate area) which was in turn greater than DHD (destroyed sample plot in semi-arid dry warm river valley climate area). SBES and SAVS of different sample plots had different life cycle patterns. In conclusion, climate and background conditions were needed for artificial propagation and restoration measures in Wenchuan Earthquake Region.