The demise of the humble bumblebee
Dave Goulson is Professor of Biological Sciences at the University of Stirling, and is the author of Bumblebees: Behaviour and Ecology. Research into bumblebees has accelerated in recent years and many new discoveries have been made with regard to their ecology and social behaviour. However, bumblebees are now suffering widespread decline – something all of us should be concerned about. In the post below, Dave Goulson explains why their numbers are declining, why we should care, and what we can do about it.
With their large size, furry, colourful bodies and slow, buzzing, slightly clumsy flight, bumblebees are among the most endearing and welcome of insect visitors to the garden. In my mind they are forever associated with the endless sunny summer days of childhood. So it is particularly alarming that these lovable insects are slowly but surely disappearing. Three of the 27 UK species have become extinct, and six more are critically endangered. Over most of the UK only a handful of species remain. Similar patterns can be seen in Western Europe, North America and even as far away as Sechuan. What has happened? Where have they gone?
The loss of our bumblebees is the result of profound changes to the countryside, particularly in the last 60 years. Pesticides were introduced widely during the second world war and their use increased steadily until the 1990s. Farmers were given subsidies to rip out hedgerows, and to plough up ancient flower-rich meadows. Well over 95% of our unimproved grasslands (haymeadows and chalk downland) were lost to cereal or silage production. Ponds and marshes were drained, heathlands ploughed, and woodlands cleared, all paid for by taxpayers money in the name of increased productivity. Faced with this onslaught, much UK wildlife suffered. Numbers of many farmland birds such as skylark and lapwing plummeted and many butterflies and wildflowers disappeared. Bumblebees depend on flowers for food, and they nest in hedgerows, woodland and old meadows. As these resources disappeared, so did the bees.
Photograph: Author’s Own
Perhaps more so than any other creatures, we should be concerned by the loss of our bumblebees. They are not just beautiful and endearing. They are a vital part of the ecosystem. They pollinate numerous wildflowers such as foxgloves, bluebells and cowslips. They also pollinate many important crops. Without them, some of the remaining wildflowers would fail to set seed, and could vanish. Crops such as oilseed rape, raspberries, currants, beans and peas would be less productive. Alarmingly, driven by concerns that wild bumblebee populations were becoming inadequate to pollinate their crops, growers of raspberries, strawberries and apples are now buying in colonies of non-native bumblebees from factories in Europe. This practice provides further threats to native bees, for they may be displaced by the incomers, or they may be exposed to novel diseases accidentally imported with the foreign bees. It would clearly be far better if we had sufficient populations of our native bumblebees to pollinate our crops.
The growing awareness of the importance of bumblebees is illustrated by the success of the Bumblebee Conservation Trust (BBCT), which was formed in 2006 and has already grown to a membership of over 5,000. The trust promotes bumblebee-friendly farming and gardening. Gardens cover over 1 million hectares, a larger area than all the UK’s nature reserves combined, so making gardens more wildlife-friendly could have a huge positive impact. Churchyards, parks and road verges can be great for wildlife including bumblebees, but are often mown too frequently, often without good reason. BBCT are trying to influence local authorities to consider bees when planning how they manage these areas.
If you would like to do your bit for the humble bumblebee, there are lots of things you can do. Look at the BBCT website for information on how to make your garden a haven for bumblebees, both by providing flowers and nest sites for them.
If we look after our bumblebees we will benefit much else besides. The flowers that they love also support a host of other creatures such as butterflies and hoverflies. By attracting and feeding the bees we can ensure that our flowers, vegetables and fruit trees are well pollinated, so that we directly benefit from better crops. With dedication and a little luck perhaps we can conserve bumblebees for future generations to enjoy.