The wetter the better for daddy longlegs – and birds!
Posted on 4 April 2011
In spring, thousands of adult crane-flies (daddy longlegs) emerge from the peat soils of UK mountains and moorland, providing a vital food source for breeding birds, such as Golden Plover, and their chicks.
Ensuring that upland peat soils remain wet will be a vital step if we are to conserve our unique upland ecosystems
Professor Chris Thomas
New research by scientists at the University of York, the Royal Society for the Protection of Birds and Aberystwyth University provides experimental evidence that management to restore the condition of our upland peat bogs may also make these vulnerable habitats more resilient to climate change.
In a paper published in Global Change Biology, they have shown that more crane-flies emerge from wetter areas of upland peat bogs, and that ongoing efforts to restore degraded peat soils can benefit crane-fly populations too. The researchers believe that the reduction in crane-fly populations caused by peatland drainage could intensify as the climate changes, posing a real risk to upland birds.
Matthew Carroll, the lead author of the paper and a PhD student in the Department of Biology at York, said: “Although upland peat bogs seem very wet, some areas can actually be fairly dry. In these drier areas, we always found lower numbers of crane-flies. Where the peat was wetter, crane-flies were more abundant. This is particularly important as climate change could cause peat surfaces to become drier. We urgently need to find ways to make upland ecosystems more resilient to these changes.”
Large areas of British peat were drained in the 20th Century in an attempt to improve upland agriculture, though many drains are now being blocked often to improve water quality.
“We wanted to know if there are also conservation benefits. Our experiment compared areas with blocked and open drains. We found that not only was peat around the blocked drains wetter, but more crane-flies emerged,” he added.
Author Dr Peter Dennis, from the Centre for Integrated Research in the Rural Environment at Aberystwyth University, said: "Mountain species of crane-flies are adapted to the cold and wet conditions of peatlands. A larger proportion of small, young leatherjackets (the larval stages of the crane-flies) dry out and die if conditions become too warm and dry."
Author Chris Thomas, Professor of Conservation Biology at York, added: “Climate change projections show that the British uplands will experience warmer, drier summers. This could be damaging enough to cause crane-fly numbers to crash. If we lose the crane-flies, then the birds that rely on them are likely to decline.
“Peat soils are one of the most important terrestrial stores of carbon. If they become too dry, they will stop accumulating carbon as new peat, and could even become sources of carbon, through erosion or oxidation of the peat. It will be the driest areas, such as those subject to drainage, that will show these problems first. Ensuring that upland peat soils remain wet will be a vital step if we are to conserve our unique upland ecosystems and the vital ecosystem services they provide.”
Dr James Pearce-Higgins, of the British Trust for Ornithology, said: 'Crane-flies are an important food source for many upland birds, such as Golden Plovers, but are sensitive to hot summer conditions. Golden Plover chicks tend to survive better when there are lots of crane-flies, and therefore Golden Plover populations are vulnerable to future warming.”
Dr Steven Ewing, RSPB conservation scientist said: “This study shows that we need to keep our upland peat bogs wet to ensure they continue to support important wildlife. The wetter the bogs are, the more resilient they are to climate change and the better they are for crane-flies and the birds that rely on them.
“On our nature reserves in the Pennines and the North of Scotland, we are blocking drains and raising water levels to restore bogs. Away from our own land, we are working with farmers, water companies and Government agencies to promote peatland restoration and make sure that both people and wildlife can benefit from healthy uplands.”
The research was funded by a Natural Environment Research Council CASE PhD studentship with the RSPB.
Notes to editors:
- The paper ‘Maintaining northern peatland ecosystems in a changing climate: effects of soil moisture, drainage and drainblocking on crane-flies’ is published in Global Change Biology.
- The University of York’s Department of Biology is one of the leading centres for biological teaching and research in the UK. In the 2008 Research Assessment Exercise, it was ranked equal first among broad spectrum bioscience departments in the UK for quality that was judged to be world-leading. The Department both teaches degree courses and undertakes research across the whole spectrum of modern Biology, from molecular genetics and biochemistry to ecology.
- The Centre for Integrated Research in the Rural Environment is a Research and Enterprise Partnership between Aberystwyth and Bangor Universities funded by the Welsh Assembly Government. The CIRRE mission is to provide evidence that enables policymakers and other stakeholders to manage sustainably the world’s limited environmental resources and the risks associated with management regimes and climate change. Peter Dennis is based at the Institute of Biological, Environmental and Rural Sciences, Aberystwyth University.
- The RSPB speaks out for birds and wildlife, tackling the problems that threaten our environment. It is the largest wildlife conservation organisation in Europe with over one million members. Wildlife and the environment face many threats. The RSPB’s work is focussed on the species and habitats that are in the greatest danger. Its work is driven by the passionate belief that birds and wildlife enrich people's lives. The health of bird populations is indicative of the health of the planet, on which the future of the human race depends. The RSPB has more than one million members, over 13,500 volunteers, 1,300 staff, more than 200 nature reserves, 10 regional offices, four country offices... and one vision - to work for a better environment rich in birds and wildlife.
- The BTO is the UK charity dedicated to research and wild birds. Over thirty thousand birdwatchers contribute to the BTO’s surveys. They collect information that forms the basis of conservation action in the UK. The BTO maintains a staff of 100 at its offices in Norfolk and Stirling, who analyse and publicise the results of project work. The BTO’s investigations are funded by government, industry and conservation organisations.
- The Natural Environment Research Council (NERC) is the UK’s main agency for funding and managing world-class research, training and knowledge exchange in the environmental sciences. It coordinates some of the world’s most exciting research projects, tackling major issues such as climate change, environmental influences on human health, the genetic make-up of life on earth, and much more. NERC receives around £400 million a year from the government’s science budget, which it uses to fund independent research and training in universities and its own research centres. For further information visit www.nerc.ac.uk.
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