Clinging on to alpine life: Investigating factors driving the uphill range contraction and population decline of a mountain breeding bird

Steven R. Ewing*, Alistair Baxter, Jeremy D. Wilson, Daniel B. Hayhow, James Gordon, Des B.A. Thompson, D. Philip Whitfield, René van der Wal

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


Climate change and anthropogenic nitrogen deposition are widely regarded as important drivers of environmental change in alpine habitats. However, due to the difficulties working in high-elevation mountain systems, the impacts of these drivers on alpine breeding species have rarely been investigated. The Eurasian dotterel (Charadrius morinellus) is a migratory wader, which has been the subject of uniquely long-term and spatially widespread monitoring effort in Scotland, where it breeds in alpine areas in dwindling numbers. Here we analyse data sets spanning three decades, to investigate whether key potential drivers of environmental change in Scottish mountains (snow lie, elevated summer temperatures and nitrogen deposition) have contributed to the population decline of dotterel. We also consider the role of rainfall on the species' wintering grounds in North Africa. We found that dotterel declines—in both density and site occupancy of breeding males—primarily occurred on low and intermediate elevation sites. High-elevation sites mostly continued to be occupied, but males occurred at lower densities in years following snow-rich winters, suggesting that high-elevation snow cover displaced dotterel to lower sites. Wintering ground rainfall was positively associated with densities of breeding males two springs later. Dotterel densities were reduced at low and intermediate sites where nitrogen deposition was greatest, but not at high-elevation sites. While climatic factors explained variation in breeding density between years, they did not seem to explain the species' uphill retreat and decline. We cannot rule out the possibility that dotterel have increasingly settled on higher sites previously unavailable due to extensive snow cover, while changes associated with nitrogen deposition may also have rendered lower lying sites less suitable for breeding. Causes of population and range changes in mountain-breeding species are thus liable to be complex, involving multiple anthropogenic drivers of environmental change acting widely across annual and migratory life cycles.

Original languageEnglish
Pages (from-to)3771-3787
Number of pages17
JournalGlobal Change Biology
Issue number7
Early online date30 Apr 2020
Publication statusPublished - Jul 2020

Bibliographical note

Previous versions of this manuscript benefitted through comments from Richard Bradbury and other reviewers. We are grateful to a large number of people who recorded detailed data during the earlier part of the study period: too many to name individually, but Keith Duncan, Stuart Rae, Rik Smith and Sue Holt were especially helpful over many years. We also thank Helen Anderson for help with creating maps and figures. We thank NERC (NE/J017019/1), Scottish Natural Heritage and Royal Society for the Protection of Birds for financial support for the PhD study by A.B. The authors declare no conflict of interest.

Funding information
Natural Environment Research Council;
Scottish Natural Heritage; Royal Society for
the Protection of Birds


  • alpine bird
  • elevation
  • nitrogen deposition
  • North African rainfall
  • snow lie
  • summer temperature


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