Characteristics and Delineation of Temporary Wetland in Lava Forest, Jeju Island

Temporary wetlands are ecosystems formed by seasonal or intermittent inundation that provide habitats and support hydrological and biogeochemical processes. Despite their importance, they are often overlooked due to their small size and ephemeral nature. The lava forest of Jeju Island, known as Gotjawal, is a rare ecosystem where temporary wetlands occur despite the high permeability of basaltic terrain. This study reports an assessment of temporary wetlands in the Seonheul Gotjawal forest, focusing on identification, boundary delineation, and key characteristics. Wetlands were identified using four years (2020–2023) of water level monitoring and vegetation surveys. Hydrological boundaries were defined by maximum observed water levels, and ecological boundaries were delineated from plant distribution. Ecological boundaries consistently fell within hydrological ones, showing the value of vegetation indicators in wetland identification. Wetland areas ranged from 347–1214 m2, with average depths of 0.2–0.9 m and hydroperiods of 13–76%. Water levels correlated with total rainfall. Three geomorphological wetland types were distinguished, with the shortest hydroperiods observed in small lava depressions functioning as forest microhabitats for endemic species. This study provides the first integrated evaluation of temporary wetlands in the Gotjawal lava forest and offers baseline data for classification and conservation.