Data gathered by a countrywide network of hundreds of ‘BeeWalker’ citizen-scientists since 2010 reveals population trends of UK bumblebees, and 2018 was a bad year.
The cold weather of the ‘Beast from the East’ delayed their breeding season and most species got off to a sluggish start, suggesting bumblebee queens were late out of hibernation and subsequently slow to produce big numbers of bumblebee workers.
As a result, many of the UK’s bumblebee species declined more quickly than normal as the year progressed, particularly as the summer heatwave reduced the available food as flowers wilted in the unusual warmth.
It was a particularly bad year for the spring-specialist early bumblebee, with 2018 being its worst since 2012.
Other, usually common, garden species which suffered included the garden bumblebee, buff-tailed bumblebee, heath bumblebee (below) and white-tailed bumblebee.
A small number of rare warmth-loving species had a very good year – brown-banded carder bee, shrill carder bee and the ruderal bumblebee are traditionally late emerging species, so the cold start had a minimal effect on them.
The impact of the 2018 heatwave has raised concerns about the number of bumblebee queens that made it into hibernation over the 2018 to 2019 winter.
2018 was the worst year for bumblebee abundance, which could have a knock-on effect for populations in 2019.
The likelihood of long heatwaves, like that of 2018, becoming more frequent could cause problems for Britain’s bumblebee populations in the longer term.
“I greatly welcome the latest BeeWalk report and thank all those who ‘Beewalked’ in 2018. Their amazing efforts allow us to answer the critical question ‘how the UK’s bumblebees are doing’ using high quality evidence,” says Gill Perkins, CEO of Bumblebee Conservation Trust.
“I’m particularly concerned by the declines reported in some of our common garden species. We all need to make sure our gardens, parks and greenspaces are bumblebee-friendly to stop today's common species becoming tomorrow's rarities."
Main image: White-tailed bumblebee. © Pieter Haringsma