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Stepping stones to the north: 'citizen science' reveals that protected areas allow wildlife to spread in response to climate change

Posted on 13 August 2012

A new study led by scientists at the University of York has shown how birds, butterflies, other insects and spiders have colonised nature reserves and areas protected for wildlife, as they move north in response to climate change and other environmental changes.

Adonis blues can only colonise new sites which already contain horse-shoe vetch, the plant species that their caterpillars eat.  These plants are restricted to grassland on chalk and limestone, most of which have been converted into agricultural crops; by S. J. Marshall (

The study of over 250 species, led by researchers in the Department of Biology at York, is published online by the Proceedings of the National Academy of Sciences of the USA (PNAS). The conclusions were based on the analysis of millions of records of wildlife species sent in predominantly by members of the public.

The work represents a major new discovery involving collaborators in universities, research institutes, conservation charities, and regional and national government but – crucially – fuelled by ‘citizen science’.

Many species need to spread towards the poles where conditions remain cool enough for them to survive climate warming. But doing this is complicated because many landscapes across the world are dominated by human agriculture and development, which form barriers to the movement of species.  The mainstay of traditional conservation has been to establish protected areas and nature reserves to provide refuges against the loss of habitats and other threats in the surrounding countryside. 

But this method of nature conservation has been questioned in recent years, partly because of continuing degradation of habitats in reserves in some parts of the world.  Increasingly, however, the value of protected areas is being question because climate change is taking place – wildlife sites stay where they are while animal species move in response to changing conditions.

However, the new research shows that protected areas are the places that most animal species colonise as they spread into new regions. “Protected areas are like stepping stones across the landscape, allowing species to set up a succession of new breeding populations as they move northwards,” said lead author Professor Chris Thomas, of the University of York.

Protected areas are like stepping stones across the landscape

Professor Chris Thomas

Co-author Dr Phillipa Gillingham, now a Lecturer at Bournemouth University, calculated that species are on average around four times more likely to colonise nature reserves than might be expected.  “For the seven focal species of birds and butterflies that we studied in greatest detail, 40% of new colonisations occurred in the mere 8.4 per cent of the land that was protected,” she said.  “Similar patterns were observed among more than 250 invertebrate species.”

But the study showed that species vary greatly in how much they need reserves.

“Some species, such as the Dartford Warbler and Silver-Spotted Skipper butterfly, are largely confined to nature reserves,” said Dr David Roy, of the NERC Centre for Ecology & Hydrology. “Whereas others like the Nightjar and Stone Curlew are less dependent on these sites.” 

Dr Richard Bradbury, of the RSPB, said: "Sites of importance for wildlife stand out like beacons in otherwise impoverished landscapes. This study shows that the hugely important role they play now will continue undiminished in the future. Protecting these arks, as well as restoring and re-creating new ones where we can, will provide the vital network enabling more species to survive the spectre of climate change."

 “This study is a great example of how volunteer recorders and national monitoring schemes together provide the information to answer key conservation questions of global importance, such as how we can help wildlife cope with climate change,” said James Pearce-Higgins of the British Trust for Ornithology. “Only through the dedicated effort of so many people can we undertake the scale of long-term monitoring required.”

Notes to editors:

  • The paper ‘Protected areas facilitate species’ range expansions’ by Chris D. Thomasa, Phillipa K. Gillinghama, Richard B. Bradburyb, David B. Royc, Barbara J. Andersona, John M. Baxterd, Nigel A. D. Bourne, Humphrey Q. P. Crickf, Richard A. Findong, Richard Foxe, Jenny A. Hodgsona, Alison R. Holth, Mike D. Morecrofti, Nina J. O’Hanlona, Tom H. Oliverc, James W. Pearce-Higginsj, Deborah A. Procterk, Jeremy A. Thomasl, Kevin J. Walkerm, Clive A. Walmsleyn, Robert J. Wilsono, and Jane K. Hilla is published online in Proceedings of the National Academy of Sciences, USA, on 13 August 2012.
  • Images of bird species and reserves are available from RSPB Images. To access an image, please click on the hyperlink below and then enter the user name and password when prompted.

    User Name:         GM_PNAS
    Password:           RSPB August 2012

    Additional species, including focal butterflies, are available at:
  • The study involved collaboration between scientists at the following institutions:
    aDepartment of Biology, Wentworth Way, University of York, YO10 5DD, United Kingdom.
    bConservation Science Department, RSPB, The Lodge, Sandy, Beds, SG19 2DL, United Kingdom.
    cNERC Centre for Ecology & Hydrology, Maclean Building, Benson Lane, Crowmarsh Gifford, Wallingford, Oxfordshire, OX10 8BB, United Kingdom.
    dPolicy & Advice Directorate, Scottish Natural Heritage, Silvan House, 231 Corstorphine Road, Edinburgh, EH12 7AT, United Kingdom.
    eButterfly Conservation, Manor Yard, East Lulworth, Dorset, BH20 5QP, United Kingdom.
    fNatural England, Eastbrook, Shaftesbury Road, Cambridge, CB2 8DR, United Kingdom.
    gDEFRA, Area 3B, Nobel House, 17 Smith Square, LONDON, SW1P 3JR, United Kingdom.
    hDepartment of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, United Kingdom.
    iNatural England, Cromwell House, 15 Andover Road, Winchester, SO23 7BT, United Kingdom.
    jBritish Trust for Ornithology, The Nunnery, Thetford, Norfolk, IP24 2PU, United Kingdom.
    kJoint Nature Conservation Committee, Monkstone House, City Road, Peterborough, PE1 1JY, United Kingdom.
    lDepartment of Zoology, University of Oxford, Oxford OX1 3PS, United Kingdom.
    mBotanical Society of the British Isles (BSBI), c/o 97 Dragon Parade, Harrogate, North Yorkshire, HG1 5DG, United Kingdom.
    nCountryside Council for Wales, Maes y Ffynnon, Penrhosgarnedd, Bangor, LL57 2DW, United Kingdom.
    oCentre for Ecology and Conservation, University of Exeter, Penryn, TR10 9EZ, United Kingdom.
  • Work was funded by the Natural Environment Research Council (NERC). NERC funds world-class science, in universities and its own research centres, that increases knowledge and understanding of the natural world. It is tackling major environmental issues such as climate change, biodiversity and natural hazards. NERC receives around £320m a year from the government's science budget, which is used to provide independent research and training in the environmental sciences.
  • More information about the University of York’s Department of Biology at
  • The Centre for Ecology & Hydrology (CEH) is the UK’s Centre of Excellence for integrated research in the land and freshwater ecosystems and their interaction with the atmosphere. CEH is part of the Natural Environment Research Council, employs more than 450 people at four major sites in England, Scotland and Wales, hosts over 150 PhD students and has an overall budget of £35m. CEH tackles complex environmental challenges to deliver practicable solutions so that future generations can benefit from a rich and healthy environment. You can follow the latest developments in CEH research via twitter @CEHScienceNews and our rss news feed
  • More information about Butterfly Conservation at
  • The BTO is an independent charitable research institute combining professional and citizen science aimed at using evidence of change in wildlife populations, particularly birds, to inform the public, opinion-formers and environmental policy- and decision-makers.' More information at

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