Assessing the effect of the landscape context on European bees

Juan Gallego Zamorano

Master's thesis

Abstract:

Bees are considered one of the most valuable biological groups providing beneficial ecosystem services, such pollination. Land-use changes and intensification have lead to bee habitat fragmentation, impeding their movement and thus the accessibility to flowers (food). However, habitat heterogeneity seems to provide a positive response in the abundance and richness of bee populations. Functional connectivity estimates the movement of bees providing insights into how the landscape context affects their abundance. However, the inclusion of landscape context variables is scarce in global biodiversity models. Here I show that the surrounding landscape is one of the most important factors affecting the total-local abundance of bees across Europe. Using a combination of PREDICTS (one of the most comprehensive global biodiversity databases) and a set of models which predict floral resource and connectivity, I calculated three landscape measurements, habitat heterogeneity (Simpon’s Diversity), accessible floral resources, and functional connectivity, in 2km buffers around 1766 sites across Europe where total abundance of bees and land use intensity was assigned, then mixed models were used for analysing the effects of the different variables. The interaction between land use intensity and the accessible floral resources was the most significant variable, particularly having a positive effect on the abundance of bees in croplands. In contrast to other studies that show the importance of habitat heterogeneity in croplands (Boscolo et al. 2017) here, there was only a positive effect in urban areas. Moreover, intermediate levels of connectivity enhanced the abundance in general. These results demonstrate the importance of the landscape configuration for the abundance of pollinators, especially the accessibility of floral resources in all kind of land uses. Large scale studies implementing different landscape variables to study pollinator abundance are rare, this research reveals the importance of improving floral spaces and connectivity to improve the ecosystem services that pollinators provide.

Keywords

Ecosystem services, Landscape ecology, Connectivity, Habitat heterogeneity, Pollination

Language used: English

Date on which the thesis was submitted / produced: 4. 12. 2017

Thesis defence

• Supervisor: prof. Dr. Mgr. Miroslav Šálek

Czech University of Life Sciences Prague

Faculty of Environmental Sciences

Master programme / field:
Engineering Ecology / Nature Conservation