sciencetech-blog

comments

Bees are being wiped out because the great British countryside is much less colourful than it once was, a study shows.

Once abundant fields and hedgerows full of wildflowers have disappeared because of intensive farming and urban sprawl.

Scientists warn this habitat loss is a bigger factor in their decline than climate change.

It means strategies to reverse bee losses needs to target and preserve their favourite plants.

Bees are being wiped out because the great British countryside is much less colourful than it once was, a study shows

In the UK it has been estimated we have lost 97 per cent of our flower-rich grassland since the 193Os.

And bees and flowers rely on each other. Bumblebees help pollinate many wildflowers, allowing them to reproduce in return for food.

Without this pollination many of these plants would not produce seeds, resulting in further declines in wildflowers which will have a knock on effect for other insects and animals higher up in the food chain.

Dr Jeroen Scheper, of Wageningen University in The Netherlands, and colleagues said: 'Growing concern about bee declines and associated loss of pollination services has increased the urgency to identify the underlying causes.

'So far the identification of the key drivers of decline of bee populations has largely been based on speculation.

'We assessed the relative importance of a range of proposed factors responsible for wild bee decline and show loss of preferred host plant species is one of the main factors associated with the decline of bee populations in The Netherlands.

Scientists warn this habitat loss is a bigger factor in their decline than climate change, pictured is a European Honey Bee 

'Interestingly species foraging on crop plant families have stable ir increasing populations.'

The findings published in Proceedings of the National Academy of Sciences mirror research in the UK showing bumblebees are under threat because changes in agricultural techniques has led to fewer wildflowers which until relatively recently was much more colourful.

Technology and demand for increased food production meant traditional farming was abandoned in favour of increasing productivity but ultimately reducing the abundance of wildflowers.

As bees rely entirely upon flowers for food, their populations began to rapidly decline in most places.

Two species have become extinct in the UK since the start of the 21st century. Cullem's bumblebee (Bombus cullumanus) was last recorded in 1941 and the short-haired bumblebee (Bombus subterraneus) in 1988.

Both are still found in Europe but the British populations may have been specially adapted to our climate and environment.

Several other species could soon follow suit - in particular the Great yellow bumblebee and the Shrill carder bee which are now only present in small numbers.

In the study the Dutch researcher Jeroen Scheper compared populations of 57 wild bee species with trends in host plants by analysing pollen on the bodies of specimens going back to before 195O.

The other main factor associated with bee decline was body size with larger ones most vulnerable, possibly because of land use changes meaning they have fewer floral resources to satisfy their greater pollen requirements.

Surprisingly diet breadth - the number of different host plants used by a species - was also of minor importance suggesting those that rely only on a few are not susceptible as long as these are not declining.

Pesticides, loss of habitat and climate change have previously been blamed for the shrinking of honeybee populations.

But the researchers said: 'These results indicate mitigation strategies for loss of wild bees will only be effective if they target the specific host plants of declining bee species.'

It's well-known bumblebees are great pollinators and so have a key role in producing much of the food we eat.

Through the pollination of many commercial crops such as tomatoes, peas, apples and strawberries, insects are estimated to contribute over £4OO million per annum to the UK economy.

If the decline of bumblebee and other insect pollinator continue, the extremely high cost of pollinating these plants by other means could significantly increase the cost of fruit and vegetables.