Successional Changes in Seed Banks in Abandoned Rice Fields in Gwangneung, Central Korea

In order to understand the role of seed banks for restoration, seed banks in abandoned rice fieldsin the Gwangneung National Arboretum, central Korea were investigated using the seedling emergence method.The study sites represented three stages: an initial stage dominated by forbs such as Persicaria thunbergii andJuncus effuses var. decipiens, a middle stage dominated by Salix, and a late stage dominated by Quercus alienaand Prunus padus (in nearby riparian forest chosen as a reference stand). DCA ordination arranged the standsaccording to the number of years since abandonment. CCA ordination identified the dominant environmentalvariables correlated most closely with Axes 1 and 2 as Mg2+ (intraset correlation was 0.827) and K+ (intrasetcorrelation was -0.677), respectively. Species richness and diversity decreased from the initial stage (H'=2.61)to the middle (H'=1.79) and late (H'=0.75) stages. A total of 49 species (/m2) and 18,620 seedlings (/m2) emergedout of the seed bank samples. The DCA ordination and similarity analysis detected a large discrepancy betweenthe composition of the actual vegetation and the seed bank. We conclude that the contribution of seed bankto restoration is low. However, seed bank may help the recovery of forbs after disturbance. Some of our resultsare consistent with the tolerance model of succession whereas others follow the trajectory of the facilitationmodel. More research on succession will be required to understand the underlying mechanisms.