[M-IS03] Wetland ecosystems under pressure, impacts on the environment and social activities

[MIS03-01] Does dechannelization mitigate the degradation of riparian vegetation?

*Yi-Kuan Zhang¹, Peter Leith Chesson^1,2, Chiou-Rong Sheue¹, Su-Chin Chen¹, Guo-Zhang M. Song¹ (1.NCHU, 2.UArizona)

Keywords:River restoration, NBS, Barrier removal, Species diversity, Early succession, River rewilding

Many streams in Taiwan have undergone severe riparian vegetation degradation due to channelization. This study aimed to determine whether dechannelization can reverse this degradation. The study site was a stream in central Taiwan, where from March to October 2023, a 187-meter-long reach underwent dechannelization. Bed stabilization structures and a concrete wall on the right bank were removed. The slope steepness and soil substrate of the streambank were restored to resemble natural stream conditions. In April 2024, we established 30 transects perpendicular to the stream randomly along both the dechannelized reach and adjacent channelized reaches. We recorded herbaceous species using the point intercept method at 0.5 m intervals along each transect. The results showed that the channelized reach was dominated by invasive species (e.g., Pennisetum purpureum, Mikania micrantha), while native species were more prevalent in the dechannelized reaches. Additionally, species diversity was higher in the dechannelized reaches than in the channelized sections. These patterns are attributed to habitat changes following dechannelization. Long-term monitoring is needed to understand successional changes and the longer-term fate of the vegetation recovery.