Great Yellow bumblebee: On the Verge

Credit: Photo: Claire Wales

The Great Yellow bumblebee (Bombus distinguendus) is one of our rarest species of bumblebee, once widespread throughout Great Britain. This species is now only found in five known locations: North West Sutherland, Orkney, Inner Hebrides, Outer Hebrides, and Caithness on the far north east of the UK mainland.

With bright yellow and black markings, this striking and distinctive rare bumblebee needs extensive meadows and other open, flower-abundant habitats such as machair to survive year-to-year. Road verges can offer this vital habitat and forage where they are managed in a way that maintains the richness of wildflowers found there.

There are several key threats to the Great Yellow bumblebee, including lack of suitable forage; lack of suitable nesting habitat and habitat fragmentation, splitting local populations into smaller units which cannot mix because of the wider distances between them. This causes a gradual decline in the genetic viability of the population over time as new queens increasingly find it harder to find suitable mates.

When managed well, road verges can provide all of the right conditions for bumblebees to thrive, providing forage, nesting opportunities and creating connections between existing populations. Unfortunately, many of the road verges in Caithness are often mown short at key times during a bumblebee’s lifecycle, which makes it very difficult for them to find enough food and safely nest.

The development year of the project aims to create a management plan for the Highland Council, using research on best practice management as well as up-to-date survey data. We will highlight where the need is greatest – the most biodiverse verges and the connections between them – to write an optimal plan which will boost the populations of the Great Yellow bumblebee and other key pollinating insects, balancing the need for road safety considerations.