| Insect pollinator diversity is essential for maintaining ecosystem health. In northern Europe, bumblebees are the most important pollinators because they have adaptations to fly in cold temperatures, but this makes them vulnerable to the higher temperatures caused by climate change. Several studies from my lab and others have shown that increased temperatures have a negative effect on bumblebees, reducing their population and ultimately reducing or collapsing their pollination services in wild and cultivated flowers. In this context, forests can potentially serve as buffer zones against climatic disturbances by providing structural complexity and relatively stable microhabitats that create favourable conditions for bumblebee nesting and overwintering. Investigating whether and how bumblebee communities use forests as climate refugia is essential for understanding their adaptive behaviour and resilience mechanisms. This project aims to improve our understanding of how microhabitat variation affects bumblebee community composition across a forest-agricultural landscape gradient, and to describe how variation in thermally functional morphological traits affects bumblebee community composition in different thermal microhabitats.
The research will take place at the Ekenäs farm, which has a gradient from forest to agricultural fields, providing an ideal setting to study bumblebee community microhabitat use. The project will be carried out over two years and is divided into two work packages (WPs). WP1 will focus on how bumblebee presence and abundance varies with thermal microhabitats across a forest-field gradient and throughout the activity season (May-September), while WP2 will investigate how bumblebee thermal traits are related to thermal microhabitat use. Bumblebees will be sampled from forest, forest edge and field habitats during spring and summer. Sampling will take place one week per month in a fixed walking transect. During each transect walk, all bumblebees observed will be counted and identified. To explore the relationship between thermal traits and microhabitat use, body size and hairiness will be measured in queens and workers captured during the transect walks. Data will be analysed using Joint Species Distribution Modelling (JSDM) to understand the environmental factors that determine species presence and abundance and their association with thermal traits. The results will help predict the effects of climate change on bumblebee communities and assess the potential of forests to act as climate refugia, helping to conserve wild bumblebee populations.
By examining how thermal traits influence bumblebee responses to temperature variation, this study aims to provide insights into the role of forests as climate refugia for bumblebee communitiies and to predict which bumblebee species may be most vulnerable to global warming. In addition, the results will improve our understanding of how to conserve bumblebee populations and their pollination services in a changing climate. The outcomes of this project align with the goal of the Oscar and Lili Lamms Memorial Foundation to conserve Swedish natural species in the natural landscape.
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