Influence of local and landscape factors on bumblebees in semi-natural meadows: a multiple-scale study in a forested landscape

Understanding the effects of local and landscape factors on bumblebees is relevant for the conservation of this group of pollinators. Bumblebees have been well-studied in agricultural landscapes of Western Europe, Asia and North America, but few studies have been developed on bumblebees in forest-dominated landscapes of Eastern Europe. We developed this study in 22 semi-natural meadows located in a patchy forested landscape of Estonia. We investigated the influence of habitat characteristics and landscape factors (calculated at four spatial scales: 250, 500, 1,000 and 2,000 m radius) on the total species richness and abundance of bumblebees. Correlation analysis, partial least squares (PLS) and stepwise forward-selection multiple regression analysis were applied in this study. The presence of a high diversity of flowering plants in semi-natural meadows may benefit the abundance of bumblebees. At the local level, patch area and shape seem to have positive and negative influences, respectively, on bumblebee species richness. At the landscape level, human settlements with the presence of gardens may favour bumblebee richness and abundance. Also, bumblebee species may increase with a high presence of meadows in the landscape, and may decrease with high percentages of forest and young forest. Overall, forested landscapes with a strong presence of edges and a diverse matrix may support a higher species richness and abundance of bumblebees. Both local and landscape factors should be considered when designing conservation strategies and agri-environmental measures.