Europe’s bumblebees threatened with extinction as their habitats shrink

Some of Europe’s bumblebees could be pushed to the edge of extinction in the next 60 years.

New research looking at the prospects of the insects suggests that over three quarters could lose at least a third of their habitat by the 2060s, with areas suitable for Arctic species set to vanish almost entirely.

A combination of climate change and habitat degradation are believed to be driving these changes, with scientists calling for action to stem the losses of the important pollinators.

Dr Guillaume Ghisbain, the lead author of the research, says, ‘For several decades, scientists have been sounding the alarm about the decline of pollinators, and bumblebees in particular.’

‘Their decline has been pronounced in many different countries, so we were only moderately surprised, although deeply saddened, by our findings.'

'As conservation biologists, we closely observe nature and communicate with colleagues around the world, all arriving at similar conclusions - pollinators are declining, often more severely than previously thought.’

The findings of the study were published in the journal Nature.

Why are bumblebees in decline?

Though there are a variety of different reasons that bumblebees are in decline, including pesticides and pollution, land use change is thought to be the main reason that the pollinators are a decreasing.

As farms have become more intensive, growing fewer crop plants in high numbers, native flowers which provide nectar for the insects have become increasingly scarce. Many species of bumblebee also need dense vegetation or disused burrows to build their nests in, which are also generally less common on modern farms.

With fewer options to feed and breed, bumblebees are becoming increasingly threatened. A 2014 study found that almost half of Europe’s 68 species are in decline, with 24% threatened with extinction.

In some countries, bumblebee species have become locally extinct, or extirpated. Three species are known to have been lost in the UK while around a fifth of Belgium’s bumblebees have disappeared.

These declines are only being exacerbated by climate change. Bumblebees are generally adapted for temperate climates, with high temperatures known to reduce their fertility, memory and survival.

Research from 2020 estimated that bumblebees were 17% less common now than in the twentieth century as a result of rising temperatures, with the risks likely to increase over time.

The researchers compared how suitable Europe’s ecosystems were for bumblebees between 1901 and 1970, as well as from 2000 to 2014. As more observations have been taken since the millennium, using a shorter time period allowed researchers to observe what changed more accurately.

In general, the analysis found habitat declines across most of Europe, averaging about a 5% drop for bumblebees. The largest drops were found in countries such as Germany, the Netherlands and Poland, where the declines could be as much as 33%.

While there were some small increases in ecological suitability in northern Scotland and Scandinavia, these were more than offset by the declines.

Forecasting the future of Europe’s bumblebees

To anticipate how bumblebees might be affected by future changes, the researchers created a series of models.

The models were trained and tested using past and present data to improve their ability to predict what could happen in the next 20, 40 and 60 years as Europe’s ecosystems and climate changed, with their findings offering similar answers to previous research.

Depending on the climate scenario used, between 38-76% of bumblebees currently classed as Least Concern on the conservation Red List will lose a significant amount of their habitat by the 2080s, and will likely become threatened with extinction.

In fact, the paper suggests that all of Europe south of Helsinki is likely to become largely unsuitable for many bumblebees, if habitat degradation and climate change continue at their current rates.

While some species, like the tree bumblebee, are set to buck the trend and become more common, their preference for certain plants and habitats mean that pollination as a whole will likely decline.

This would have significant implications for food security across the continent, with crops such as tomatoes, strawberries and aubergines depending on bumblebees for pollination. While these plants can be pollinated by hand, this is a much more labour-intensive and time-consuming process.

As habitats become less suitable, many bumblebees are likely to retreat further north, or to higher altitudes. While this is potentially promising as a refuge for some bumblebees, Guillaume warns that it’s not a perfect solution.

‘Regions such as Scandinavia, with its relatively cool climate and mountainous landscape, could potentially be a place for some species to live in the future if it is not excessively altered by human activities,’ Guillaume says.

‘However, for this to happen, it will be essential to ensure that the region remains free of other factors of decline that we didn’t account for in our models, such as the effects of extreme weather, pesticides, and disease.’

Even if Scandinavia and similar regions are kept free of human intervention, there’s still no guarantee that bumblebees will be able to migrate there.

To help stem bumblebee declines, restoring habitats will be crucial. Even small patches of nectar-rich plants, such as back gardens or window boxes, can provide stepping stones for bumblebees between different areas and help their populations to withstand the pressures affecting them.

With wider changes, it’s still possible that the bleak picture presented by the research’s worst case scenarios can be avoided.

‘While these steps can help bumblebees, their survival will ultimately depend on how we protect our natural habitats and climates at a large scale,’ Guillaume says.