As urbanization progressed, artificially created natures have increased. It is important for understanding the structural and functional properties of these new types of ecosystem. The purpose of this study is to investigate topological properties and ecological stability of an artificial stream using food-web network analysis. The study site is Cheonggye stream, in Seoul, Korea, which was restored to the artificial stream with discharge regulating system in 2005. To identify the properties of Cheonggye stream, 38 food-webs were constructed based on biological monitoring data (2008-2015) and global biotic interactions (GloBI) database. We analyzed the topological properties of the constructed food-webs by measuring their link densities and connectances and examining whether they have small-world or scale-free structure. Robustness index was used to assess ecological stability of the food-webs.
Results/Conclusions
The result presented that link density and connectance of the food-webs range from 0.90 to 3.18 and from 0.029 to 0.114, respectively. The range of connectance was similar to that of general natural food-webs, but link density tended to be relatively low. Unlike the natural food-webs, Cheonggye stream was identified to a scale-free network due to the existence of hub species. As a result of ecological stability, Cheonggye stream had a increasing tendency of robustness over time, indicating that it has been stabilized since the restoration. Overall, artifical streams have different properties compared to natural system and are becoming ecologically stable. Since we focused on static analysis of the food-webs in this study, temporal and spatial approaches are necessary to appropriately interpret the varying structural and functional properties.