Vascular plants occurrences in Dokdo islands, Korea, based on herbarium collections and legacy botanical literature

Purpose: The present project was focused on digitizing the data on plant distribution on Dokdo Islands, collected between 1947-2018 by botanists taking part in occasional expeditions to the islands. These data are expected to contribute to the biodiversity management and conservation of these highly inaccessible island ecosystems.

The small islands Dokdo are volcanic rocks formed in the Cenozoic era, more specifically 4.6 to 2.5 million years ago, which is attributed to the same formation mechanism of underwater islands (Jo et al., 2021; Kim et al., 2013). The Dokdo volcano rises about 2,100 m from the sea bottom, and the diameter of the submerged mountain is more than 10 km (Song et al., 2017). The shape of the islands is butterfly wings, its relief is relatively steep, its highest elevation reaches 168 m above sea level, and its surface area is about 18.7 hectares. The Dokdo islands consist of two main islets, Seodo and Dongdo, with numerous surrounding rocks. Seodo has several access points for berth and tracking routes, and flora surveys and collections are possible over a comparatively large area. Since Dongdo was more difficult to access by boat, it is quite difficult to stride for investigation on the surface, except there are fewer primary species occurrence data in few points. Dokdo island had a mean annual temperature of 13.8C, mean annual precipitation of 589 mm, an absolute minimum temperature of -6.4C, and an absolute maximum temperature of 28.2C. The Dokdo climate is distinguished from the Ulleung islands by the relatively less precipitation (up to 1,500 mm per year). Meteorologists suspected that auto weather systems tended to underestimate the amount of snowfall, and also, there has been a lot of missing data (Kim and Park, 2017).