Constructed wetland (CW) in urban areas have demonstrable effects on the urban ecosystem services and biodiversity. It has been sufficiently established that the urban ecosystem services and biodiversity are vulnerable to environmental impacts. Many studies have been conducted on the method of wetlands monitoring, but to the best of our knowledge, there has been little research about multifaceted CW monitoring in urban areas. Notably, as the restored-CWs in urban areas demonstrate high temporal variabilities, it is crucial to managing the vegetation structures by detecting their structural changes; therefore, we aimed to assess the changes in the restored-CWs vegetation structures. Moreover, our study sites are restored-CWs located in Busan, Iksan, and Incheon in South Korea. We acquired the vegetation data by conducting field surveys using the drone-based digital aerial photogrammetric method and operating simultaneous localization and mapping LiDAR. All surveys were conducted from March to November 2019. Finally, we analyzed the structural indices, such as the compositions of wetland vegetation, and voxel-based volumes.
Results/Conclusions
The results demonstrated that in Busan CW, the dominant species was Nymphoides peltatum. The open water area reached a peak of 409.56 ㎡ in March, and the mean ratio of the open water area was 17.9±10.5 %. The maximum change in the distance of the vegetation was 2.2m, and the average change in distance was 0.2±0.3 m. Next, in Iksan CW, the dominant species were Nymphoides peltatum and Typha angustifolia. The open water area maximum reached 423.4 ㎡ in March, and the mean ratio of open water area was 13.3±8.4 %. The maximum change in distance experienced by vegetation was 2.3 m, and the average distance change was 0.5±0.4 m. Moreover, in Incheon CW, the dominant species were Spirodela polyrhiza and Lemna minor. Regarding the open water area, the maximum was 2,879.5 ㎡ in March, and the mean ratio of the open water area was 39.5±18.9%. Additionally, the maximum change in distance of the vegetation was 5.7 m, and the average change in distance was 0.1±0.4 m. These results suggested that the range of changes in vegetation in the CW is rapid, and the management of emerged plants and floating-leaf plants is important for open water maintenance. This study offers some insight into the sustainable CW, quantitative monitoring is efficient for the understanding of vegetation structure.
This study is supported by Korea Ministry of Environment (MOE, Project No. 2018000210007) as "Public Technology Program based on Environmental Policy".