• Korean Journal of Environment and Ecology
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• v.33 no.1
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• pp.16-27
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• 2019

This study was identified the survey period and emergence of main species of dragonfly species, an indicator species that can identify the characteristics of wetland ecosystem. I surveyed the species and population of dragonflies once every two weeks from May 2015 to October 2016(29 times). From January to March, November and December were excluded from the cluster classification because the dragonflies were not observed. In April and October, the species was emerged but it was not suitable because it could not represent the time of the seasons. When we divide by month, it was able to judge from April to June as spring. Except the May, there were some changes due to rainfall and temperature, and sometimes June was included in the summer season. June, July and August correspond to summer, and September and October fall in Autumn. In June and October, the change was expected due to the effects of temperature and so it was judged as a partial fit. Looking at the change of the species, Coenagrion johansson and Paracercion calamorum were increase at the spring, and then Crocothemis servilia mariannae, Paracercion calamorum, Anax nigrofasciatus, Lyriothemis pachygastra, Orthetrum melania were abruptly enlarge in summer. At last, Sympetrum kunckeli, Lestes temporaris tended to be higher in Autumn.

• Korean Journal of Environment and Ecology
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• v.34 no.6
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• pp.515-529
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• 2020

Constructed wetlands undergo biological and physical changes such as an increase in the proportion of arid plants due to the natural succession process after formation. It can adversely affect not only the purification function but also the habitat of species. As such, this study aims to identify environmental factors affecting biodiversity and propose management plans based on the monitoring results of physical environmental changes and the emergence of species in seven constructed wetlands selected based on the water depth and surrounding conditions among the lands purchased by the Nakdong River basin. We examined the environmental conditions and emergence of the Odonata, which is a wetland-dependent species, to predict the trend of changes in biodiversity and abundance. The results showed that the open water area decreased as the emergent plants spread to the deep water in 2015 compared to 2012 when they were initially restored to a depth of 0.2 to 1 m. While a total of 54 dragonfly species were observed, the habitat diversity, such as vegetation, water surface, and grassland, remained similar to the initial formation of the wetlands despite the expansion of the emergent plants. On the other hand, the number of Agrionidae species, which prefer areas with fewer aquatic plants, decreased between 2012 and 2015 due to the diminished water surface. The p-values of the differences in the number of species and population between wetlands by year were 2.568e-09 and 1.162e-08, respectively, indicating the statistically significant differences. The decrease in open water surface was found to have the greatest effect on the biodiversity and habitat density of dragonflies. The time-series survey of constructed wetlands confirmed that the spread of Phragmites communis, P. japonica, Typha orientalis, etc., caused a decrease in species diversity. It suggests that environmental management to maintain the open water surface area is necessary.