Feasibility of seed bank for restoration of salt marsh: a case study around the Gwangyang Bay, southern Korea

Abstract

Salt marsh is an important transitional zone among terrestrial, riverine, and marine ecosystems and is a productive habitat that interacts extensively with adjacent landscape elements of estuarine and coastal ecosystems. Nowadays, in addition to various human activities, a variety of natural processes induce changes in salt marshes. This study aims to provide background information to restore disturbed salt marshes and to propose their ecological restoration using seed banks. The study area is a prepared area for the Gwangyang Container Port located in the southern Korea. This area was formed by accumulating mud soils dredged from the bottom of the forward sea. This land was created in a serial process of preparing the Gwangyang container port and the salt marsh was passively restored by seeds buried in mud soil dredged from seabed. As a result of stand ordination based on vegetation data collected from the land, stands were arranged according to tolerance to salinity in the order of Suaeda maritima, Salicornia europaea, and Phragmites communis communities on the Axis 1. Landscape structure of the projected area was analyzed as well. Edges of the projected area were divided from the marginal waterway by the dike. Four types of vegetation appeared on the dike: Alnus firma plantation, Robinia pseudoacacia plantation, Lespedeza cyrtobotrya plantation, and grassland. In the more internal areas, two types of vegetation sequences appeared: Aster tripolium community-Suaeda glauca community-Salicornia europaea community sequence and Aster tripolium community-Suaeda maritima community-S. europaea community sequence. Mixed community showed the highest species diversity (H′ = 0.86) and S. europaea community showed the lowest (H′ = 0.0). Evenness is the highest in Mixed community (J′ = 2.26) and the lowest in S. maritime-S. europaea community (J′ = 0.0). Several plant communities were successfully established on the land created by mud soil dredged from the bottom of Gwangyang Bay. Moreover, community diversity in this area approached a similar level with those from other studies involving natural salt marshes. Therefore, restoration effect based on community diversity obtained in our study can be evaluated as a successful achievement. In this respect, although most salt marshes in Korea and other places worldwide have been destroyed or disturbed by excessive land use, feasibility of seed bank as a restoration tool is greatly expected.

Spatial distribution of vegetation along the environmental gradient on the coastal cliff and plateau of Janggi peninsula (Homigot), southeastern Korea

“…Cliffs are a major plant habitat around the coastal area, but in contrast to sand dunes (Jung and Kim 1998;Kim et al 2009;Shin et al 2015) and salt marshes (Min 1985; Lee and Kim 1988;Ihm 1989;Lee 1989;Ihm et al 1998a;Ihm et al 1998b;Kim et al 2005;Han 2008;Lee et al 2009;Lee et al 2012), they have been little investigated in Korea. There are simple descriptions of cliff vegetation in studies on island vegetation (Lee et al 2003;Song et al 2008;Song et al 2009;Choi et al 2012;Kim 2012;Kim et al 2013), but there is no published paper, which addressed sea cliff vegetation synthetically.…”