2025-09-25 ワシントン大学（UW）
In a new study, a team of scientists determined the minimum natural habitat on agricultural land that will allow insect pollinators — including bumble bees (shown here), solitary bees, hoverflies and butterflies — to thrive.April Hong/ University of Washington
＜関連情報＞
- https://www.washington.edu/news/2025/09/25/insect-pollinators-need-more-higher-quality-habitats-to-help-farmers-bees/
- https://www.science.org/doi/10.1126/science.adr2146
農業景観における花粉媒介者の効果的な保護のための重要な生息地閾値 Critical habitat thresholds for effective pollinator conservation in agricultural landscapes
Gabriella A. Bishop, David Kleijn, Matthias Albrecht, Ignasi Bartomeus, […] , and Thijs P. M. Fijen
Science Published:25 Sep 2025
DOI:https://doi.org/10.1126/science.adr2146
Editor’s summary
Many species are declining, with lack of adequate habitat being a primary driver. Providing habitats in human-dominated landscapes is essential for maintaining populations and supporting ecosystem functions such as pollination, but habitat protection targets in such landscapes are poorly defined. Bishop et al. developed a framework to assess habitat needs based on the threshold at which populations respond more to increased habitat quality than quantity. They used a meta-analysis to define habitat quantity thresholds, using floral resources as a proxy for habitat quality, for insect pollinators (bumble bees, solitary bees, butterflies, and hoverflies) in agricultural landscapes. Hoverflies had a much lower threshold because of low habitat quality, and this framework could be adapted to guide targets for other taxa. —Bianca Lopez
Abstract
Biodiversity in human-dominated landscapes is declining, but evidence-based conservation targets to guide international policies for such landscapes are lacking. We present a framework for informing habitat conservation policies based on the enhancement of habitat quantity and quality and define thresholds of habitat quantity at which it becomes effective to also prioritize habitat quality. We applied this framework to insect pollinators, an important part of agroecosystem biodiversity, by synthesizing 59 studies from 19 countries. Given low habitat quality, hoverflies had the lowest threshold at 6% semi-natural habitat cover, followed by solitary bees (16%), bumble bees (18%), and butterflies (37%). These figures represent minimum habitat thresholds in agricultural landscapes, but when habitat quantity is restricted, marked increases in quality are required to reach similar outcomes.
