Extinction Risk Status of Grassland Plants

Insights from Japan's Red Lists (1997-2020) and Changes in Habitat Area

Abstract

Increasing the number of conservation areas for biodiversity has become an international challenge. It is crucial to identify habitats that should be prioritized for conservation to enhance the effectiveness of these measures. This study utilized the 1997, 2007, and 2020 Red Lists of vascular plants from the Ministry of the Environment of Japan.The study aimed to identify habitats important for the conservation of endangered species on a national scale in Japan, using the Red Lists from 1997, 2007, and 2020. The habitats of endangered species were examined using illustrated books and classified into the following categories: "grassland," "wetland," "beach," "rocky land," "agricultural land," "road," "forest," "forest edge," and "aquatic." Forests had the highest number of endangered species per habitat type, followed by rocky areas, wetlands, grasslands, forest edges, beaches, farmlands, aquatic areas, and roads. The number of endangered species was higher in grassland-like habitats, where plants other than tall trees are dominant, compared to forest-like habitats, where tall trees are dominant. Although the increase in the extinction rank of endangered species was not statistically significant, there was a slight trend towards a higher rate of increase at forest edges and beaches. The density of endangered species per area in grassland habitats was 27 times higher than in forest-like habitats in 1963. This disparity has grown significantly in recent years, with the difference being 96 times higher in 2020, due to the rapid decline in the grassland area. The density of endangered species and their rate of increase indicate that grassland habitats are more critical for the conservation of endangered species than forest-like habitats.