Relationship between biodiversity and landscape structure in the Gyungan stream basin, central Korea

The relationship between landscape structure and biodiversity was investigated in the Gyungan stream basin, central Korea, in order to prepare a biodiversity conservation plan. The study area was divided into upstream, midstream, downstream and Gonjiam stream sub-watersheds based on the land use pattern of each sub-watershed. The quality of the terrestrial landscape was assessed by connectivity and percentages of deciduous broad-leaved forest and urbanized area. The quality of the terrestrial landscape was the highest in the downstream sub-watershed followed by Gonjiam stream, midstream and upstream sub-watersheds. The quality of the riparian landscape assessed by percentages of the number and the area that the wetland vegetation elements occupy in the whole area showed a similar trend to that of terrestrial landscape. The diversity of all taxa including fish, reptiles and amphibians, birds, mammals and wetland vegetation except benthic macroinvertebrates was the highest downstream. The diversity of benthic macroinvertebrates was the highest in the Gonjiam stream sub-watershed. Thus, biodiversity was shown to be the highest in the downstream sub-watershed, followed, in order, by Gonjiam stream, midstream and upstream sub-watersheds in proportion to landscape quality. On the other hand, the quality of the aquatic environment based on the ecological score of benthic macroinvertebrate (ESB) index was the highest downstream, followed, in order, by upstream, Gonjiam stream and midstream areas. This trend is different from that of biodiversity. In order to improve landscape quality degraded by excessive land use and to increase biodiversity, we recommended a restoration plan that addresses both ecosystem and landscape.