Forest‐associated distribution of Sympetrum frequens (Odonata: Libellulidae), a common, regionally declining meadowhawk in Japan

Abstract

Sympetrum frequens , a common yet regionally declining dragonfly in Japan, is likely to use forests as seasonal habitats during the adult stage. After emerging from lowland wetlands in early summer, adults move to montane forests to avoid summer heat, and they return to the lowlands for reproduction in autumn, where they roost and forage in nearby forests. However, the spatial patterns of forest habitats remain unclear, probably because detecting individuals within forests is difficult. In contrast, after leaving forests, they become observable in foothills in late summer and in lowland paddy fields during autumn, where their distribution may retain the spatial legacies of recent forest use. This study analyzed the relationships between adult abundance observed during these periods and the surrounding forest landscapes across multiple spatial scales and elevation bands in central Japan to infer the forest habitats they previously occupied. In late summer, a significant positive effect of forest area at elevations of 400–600 m (average summer temperature range: 23.8–25.4°C) within 5 km best explained the number of adults at foothills. In autumn, adult abundance in the lowland paddy fields was best explained by a significant hump‐shaped relationship with forest area within 5 km, peaking at approximately 40% forest cover. These results suggest spatial and climatic structuring of their seasonal forest habitats, which may advance our ecological understanding and inform conservation planning for this species. Furthermore, this study underscores the value of landscape analysis that uses the outside‐forest abundance of multi‐habitat species to identify forest habitats.