• Korean Journal of Environment and Ecology
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• v.38 no.4
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• pp.375-387
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• 2024

This study investigated the ecological characteristics of Fraxinus chiisanensis Nakai, one of the endemic and rare plant species in Korea, based on its distribution status, characteristics of the growth environment, and species composition. A vegetation survey that analyzed the correlation between species distribution patterns and environmental variables, along with the traits of the emergent plant species, was performed according to the explanation of environmental growth conditions and phytosociological method for the location where F. chiisanensis is found. A total of 19 dominant locations and 9 non-dominant locations of F. chiisanensis were observed in 28 study sites in 12 regions, and a total of 155 taxa were observed. According to the vegetation climate of Korea, the growth environment of the study site where F. chiisanensis is located is characterized as cold and is primarily situated within the northern temperate deciduous broadleaf forest zone. The average elevation was 859m above sea level, with an average rock exposure of 60.4%, soil exposure of 24.7%, and an average slope of 18.7°. The taxa belonging to the top P-NCD(Percentage of Net Contribution Degree) among the emergent species were mostly designated as the taxa emerging in valley vegetation. The correlation analysis of environmental variables revealed that altitude had the strongest correlation, with rock exposure showing the second highest correlation. The ongoing dynamics of the F. chiisanensis forest are anticipated to persist due to the high P-NCD values exhibited by the F. chiisanensis within the shrub and herbaceous layers among the taxa associated with tree species. Most F. chiisanensis habitats are currently situated within protected regions such as national parks, provincial parks, and county parks, where there are relatively minimal human-induced disturbances. However, there is potential for damage in areas not designated as protected, such as forest tending operation sites or new hiking trails. Concerns about declining habitat quality have prompted suggestions for management strategies such as establishing Forest Genetic Resource Reserves in these locations. In addition, follow-up and further research should be conducted to identify possible sites for distribution and establish candidate conservation areas based on various environmental conditions of F. chiisanensis.

• Korean Journal of Ecology and Environment
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• v.42 no.3
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• pp.350-363
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• 2009

Inter- and intra-specific differences in removal activities, filtering rates (FR) and production of feces-and pseudo-feces (PF) between a native freshwater bivalve in Korea, Anodonta woodiana Lea and Unio douglasiae Griffith et Pidgeon, were compared using a continuous removal of organic matters (CROM) system. The CROM system comprised five steps; input of polluted water, control of water flow, mussel treatment, analysis of water quality and discharge of clean water. The study was designed to compare the removal activity of organic matters between A. woodiana and U. douglasiae, and the intra-specific differences between density and length in A. woordiana. Results clearly indicate that two kinds of mussels had obvious removal activities of seston in the eutrophic reservoir. First, if both are similar in shell length, there were no significant inter-specific differences in removal activity between A. woordiana and U. douglasiae (P>0.5), but FRs of U. douglasiae was relatively high due to low ash-fee dry weight. Second, if both are same in animal density, the smaller mussels (1$\sim$2 years old) showed a higher filtering rate and production of feces- and pseudo-feces and less release of ammonium than the larger mussels. Third, if both are same in biomass, FRs and PF of mussels were higher in the low-density tank than the high-density tank, While the Concentration of $NH_4$-N and $PO_4$-P released WRS similar to each other (P>0.5). Therefore, these results suggest that CROM system using a young bivalve A. woordiana can be applied to control the nuisance seston in eutrophic lake system, if a relevant species and density were selected. Additional pilot tests to optimize the age and density of domestic bivalves were needed for the generalization of CROM operation.