Britain’s birds facing extinction as climate change leaves them with nowhere to go
Posted on March 9, 2009
Filed Under 1 |
Scientists have calculated that the average range of British birds will move 550 kilometres (340 miles) to the north by 2100 as the climate heats up.
In a study to be published on Wednesday in the journal Public Library of Science, researchers will reveal they have found detailed evidence to show a significant wildlife transformation is under way.
The report, by Durham University and the Royal Society for the Protection of Birds (RSPB), outlines changes that have already occurred in the past two decades in response to the 0.6C rise that has affected the nation.
Two particular birds provide telling evidence of the future facing the British countryside and its inhabitants: the lapwing and the cirl bunting, a relative of the yellowhammer. The cirl bunting is common around the Mediterranean, although its range has steadily moved northwards until, late last century, a breeding colony was established in the south of England. By 1989 there were 118 breeding pairs. Today the population has spread and there are now more than 700 pairs. By the end of this century, cirl bunting are likely to be found throughout most of England and Ireland.
By contrast, the lapwing - one of the most characteristic British farmland birds of the 19th and 20th centuries - has suffered devastating drops in population because of changes in agriculture, in particular the introduction of winter-sowing of crops. Now global warming is adding to these effects, with the result that the lapwing has already suffered a 47% reduction in numbers and seems destined to earn itself the status of an endangered species in Britain.
However, it is the very north of Britain that faces the most worrying changes. Apart from the Scottish crossbill and the snow bunting, the Arctic skua, Leach’s petrel and the common scooter also face extinction by the end of the century.
“There is simply no place left for these birds to go,” said Graham Madge of the RSPB. “The crossbill is now confined to the very north of Scotland. As Europe heats up, only Iceland offers the prospect of a new homeland. However, the crossbill cannot fly that far - certainly not enough across the North Sea. Similarly, the snow bunting has had to move further and further up the Cairngorms as the climate has warmed. Basically it is running out of mountain.”
In a separate study published last week, Dr Willis also studied the impact of global warming on insect life and in particular on butterflies. His research showed that species cannot migrate fast enough to keep up with global warming. “The nation’s temperature gradient is moving northwards at a rate of about 4km a year, while the butterflies are only capable of moving range at about 1km a year,” said Dr Willis. “This implies that birds - which feed on insects - could face serious problems in finding food as they move north.”
“In the past, climate change has affected wildlife in these islands,” added Dr Willis. “However, species have adapted because these changes were relatively gradual. But what is happening now is so rapid, birds simply cannot adapt, and so face extinction.”
75% of common European birds at risk from climate change
Climate change is already having a detectable impact on birds across Europe. This is the message from a group of scientists who have created the world’s first indicator of the impacts of climate change on wildlife at a continental scale. “We hear a lot about climate change, but our paper shows that its effects are being felt right now”, said lead author Dr Richard Gregory from the RSPB (BirdLife in the UK).
Of the 122 common species included in the analysis, 75% are predicted to experience declines across their ranges if they continue to respond to climatic warming in the way the models predict, and in the absence of other barriers. The remaining 25% are projected to increase.
“The results show the number of species being badly affected outnumbers the species that might benefit by three to one”, commented Dr Gregory. “Although we have only had a very small actual rise in global average temperature, it is staggering to realise how much change we are noticing in wildlife populations. If we don’t take our foot off the gas now, our indicator shows there will be many much worse effects to come. We must keep global temperature rise below the two degree ceiling; anything above this will create global havoc”.
Published in the journal PloS ONE, scientists showed a strong link between the observed population change of common and widespread European bird species and the projected range change associated with climate change. By pulling all the data together, the team compiled an indicator showing how climate change is affecting wildlife across Europe. The new indicator has already been included in a high profile set of indicators being used by the European Commission to assess progress towards the target of halting biodiversity loss by 2010.
Dr Stephen Willis, of Durham University, said: “Our indicator is the biodiversity equivalent of the FTSE index, only instead of summarising the changing fortunes of businesses, it summarises how biodiversity is changing due to climate change. Unlike the FTSE, which is currently at a six year low, the climate change index has been increasing each year since the mid-1980s, indicating that climate is having an increasing impact on biodiversity”.
“This is the first robust indicator of climate change impacts on biodiversity”, said Dr Stuart Butchart – BirdLife’s Global Research and Indicators Coordinator. “There are numerous measures of how our climate is changing, and good evidence that these changes are impacting species and habitats, but to date there has been no simple indicator graph for decision makers to use to monitor these impacts over time. It provides another example of how information from birds – the best known class of organisms – can be used to monitor our growing footprint on the planet”.
Comments
Leave a Reply
