Ecological Responses and Management Strategies for a Mountainous Abandoned Paddy Wetland Following Severe Wildfire

Abstract Mountainous abandoned paddy wetlands act as crucial biodiversity hotspots formed through secondary ecological succession, yet they face severe threats from climate-driven wildfires. This study evaluated the spatial severity patterns and multi-taxonomic biodiversity responses following a high-intensity wildfire in March 2025 at the Yeongyang Janggumegi Protected Wetland Area, South Korea, where agriculture was abandoned approximately 25 years ago. Topographic-meteorological interactions led to distinct spatial burn severity: steep upslope western slopes suffered complete canopy combustion, whereas the central standing water and deep valley floors functioned as vital micro-refugia. Post-fire monitoring revealed a 15.0% reduction in total species richness (from 472 to 401 species) and a 50.0% decline in endangered species (from 6 to 3 species). Significant population collapses were observed in birds (-56.9%), benthic macroinvertebrates (-56.9%), amphibians and reptiles (-55.6%), mammals (-21.4%), and terrestrial insects (-17.1%), driven by canopy destruction, microclimate desiccation, and water quality degradation. Conversely, plant species richness increased by 9.9% (from 222 to 244 species) due to the rapid influx of heliophilic weeds and non-wetland annuals, signaling an alarming risk of transition toward a non-swamp state. To mitigate post-fire degradation, we propose four operational adaptive management strategies: (1) installing soil erosion barriers on high-severity slopes to prevent ash influx, (2) establishing Ecosystem Protection Zones around central hydrological micro-refugia, (3) controlling invasive weeds to promote native wetland flora (Salix and Alnus spp.), and (4) deploying artificial micro-refugia alongside long-term biological monitoring targeting EPT taxa and amphibians.