Conservation methods and their effects on flower-visiting insect diversity in Japan

Abstract

Flower-visiting insects are essential for the pollination of both wild and cultivated plants, but their populations have declined due to global environmental changes caused by human activities. Conservation of flower-visiting insects is therefore a pressing issue internationally that has led to conservation activities and conservation-directed ecological research worldwide, including in Japan. However, very few Japanese-language textbooks and review articles comprehensively introduce the methods used to conserve flower-visiting insects in Japan, and the materials necessary to conduct local conservation activities are lacking. In this paper, we provide a summary of the comprehensive conservation methods that have been developed for flower-visiting insects, mainly in Japan. Three topics are introduced: conservation methods in forest, agricultural and urban landscapes, as the main habitats of flower-visiting insects; actions against sika deer, which have caused catastrophic damage to nectar-providing plants and flower-visiting insects in recent years; and methods for restoring the habitats of flower-visiting insects and nectar-providing plants. For methods lacking research carried out in Japan, such as the use of bee hotels in the restoration of flower-visiting insects’ habitat, research conducted overseas is introduced, as appropriate. Given the increasing threat to flower-visiting insects, research in areas for which knowledge is still scarce should be promoted. Conservation and restoration methods should also be developed and their effectiveness verified.