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Introduction
The world climate is changing as a result of
human activities. In Britain, during the 20th Century, annual
average temperatures rose by almost 1 ºC. By 2080, temperature
is expected to rise by 2 to 3.5ºC and sea-level by between
–2 and 86 cm. The distributions of wildlife and plants are
changing throughout the world and some fingerprints of climate
change are visible in Britain. Waterbird surveys provide one of
the most largest datasets in the world: more than 3,000 sites
have been monitored across Europe for over 25 years. Such information
could guide future government conservation strategies. This may
be necessary given the importance of Europe for waterbirds. |
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| Changing
wader distributions |
Since the mid-1980s seven of nine species of wader occurring
in internationally important numbers have moved in an eastwards
direction along the winter isotherms with increasing mean winter
temperature (Austin & Rehfisch 2005). Between 1980 and 2001,
the weighted centres of the over-wintering populations of seven
species of wader in north-west Europe have undergone marked
shifts in a northerly or north-easterly direction. Species such
as Curlew, Grey Plover, Dunlin and Black-tailed Godwit have
shifted their distributions by more than 50 miles (Maclean et
al. in review).
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| Curlews, like many other waders
have declined in the southwest, but increased in the northeast
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| Specific
responses to climate change |
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On UK estuaries, the smallest species of
waders have undergone the greatest shifts in their distribution,
as would be expected if such shifts are due to changes in temperature
(Austin & Rehfisch 2005). In north-west Europe, changes in
site abundance of all seven species of wader included in analysis
is temperature dependent. Numbers are increasing in response to
warming temperatures on colder sites, but not on warmer sites
(Maclean et al. in review). In north-west Europe, changes in site
abundance of all seven species of wader included in analysis is
temperature dependent. Numbers are increasing in response to warming
temperatures on colder sites, but not on warmer sites (Maclean
et al. in review). |
| Relationship between temperature
response and body mass |
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Future changes |
| Based on present associations between waders and weather,
some wader species, may decline considerably under the 2080 UKCIP
scenarios and if flyway populations do not decline Britain may no
longer hold internationally important populations of these species
(Rehfisch et al. 2004). |
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Ringed Plover distributions
(a) in 1984-85 and predicted densities in 2080 under the (b) medium-low
and (c) high UKCIP climate change scenarios relative to the 1960-1990
baseline |
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| Observed historic
increases in wader numbers over-wintering in north-east Europe
are likely to continue. The Baltic region is likely to host increasingly
important numbers of waders. Declines may occur in some parts
of south-west Europe (Maclean et al. in review). |
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| Thirty-year trends
in numbers of selected wader species in parts of the north-east
and south-west of Europe. In the north-east numbers are generally
increasing, but in the south-west decreases in France due to climate
change are more than compensated for by increases due to a reduction
in hunting pressure. In Wales, numbers are declining |
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Conservation implications |
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The recent decline in eight of the 14 species
of common coastal wader in Britain could be due in part to the
waders now wintering even further north and east, on the European
mainland (Rehfisch & Crick 2003).
Waders are designated features of Special Protection
Areas (SPAs) that regularly hold 1% or more of their flyway wintering
population. As wader distributions change with climate change,
numbers of some species on some British SPAs are dropping below
the 1% threshold such as is the case for Dunlin on the Severn
SPA. |
| Dunlin numbers on Severn SPA against
international threshold (dotted line) |
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References
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Austin, G. & Rehfisch, M.M.
(2005) Shifting non-breeding distributions of migratory fauna
in relation to climatic change. Global Change Biology, 11: 31-38.
Hulme, M. et al. 2002. Climate change scenarios
for the United Kingdom: the UKCIP02 scientific report. Tydall
Centre, University of East Anglia, UK.
Maclean, I.M.D. et al. (in review) Global warming
causes rapid changes in the distribution and abundance of birds
in winter. Global Change Biology
Maclean, I.M.D. et al. (2005) WeBS Alerts 2003/2004:
BTO Research Report No. 416, Thetford.
Parmesan, C. & Yohe, G. 2003. A globally coherent fingerprint
of climate change impacts across natural systems. Nature, 421,
37-42.
Rehfisch, M.M. et al. (2004) The possible impact
of climate change on the future distributions and numbers of waders
on Britain’s non-estuarine coast. Ibis, 146, S70-S81.
Rehfisch, M.M. & Crick, H.Q.P. 2003. Predicting
the impact of climatic change on Arctic-breeding waders. Wader
Study Group Bull., 100, 86-95.
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