Many bird species are showing distributional change in response to global warming. New research using data collected by volunteers taking part in the Wetland Bird Survey shows that Europe's winter population of Smew has redistributed north-eastwards due to milder winter conditions in the last 25 years. In the UK, a small population of typically less than 200 Smew (and in mild winters just a few dozen birds) can be found in winter at favoured gravel pits and reservoirs in lowland England. This UK population has approximately halved since the late 1990s.  This study, compiled by scientists in 16 countries (including BTO staff) shows that Special Protection Areas (SPAs) scheduled under the EU Birds Directive, facilitate such distribution change across a species’ entire range. Currently, one third of the total population winters in north-eastern Europe, compared to 6% two decades ago. Furthermore, population growth rate in this region was also twice as fast inside EU Birds Directive’s SPAs compared to those outside over the last 25 years.

Thus, well designed protected area networks can mitigate the effects of climate change on biodiversity by safeguarding high quality habitat as species adopt new distributions. These findings confirm that the existence of Special Protection Areas assists species to cope with climate change.  However, the results also highlighted severe gaps in the EU Special protection Area network, especially in northern parts of the wintering range. Many countries designated their SPAs more than 20 years ago, when no account was taken of the rapid environmental changes now occurring. More than eight out of ten Smew wintering in Latvia and Sweden do so in currently unprotected areas, and in Finland nearly all individuals winter outside the SPA network. Despite this range shift, it is still important to maintain the network at the southern end of the birds’ range, so that they have somewhere to retreat during particularly harsh winters. Studies such as this can help policy makers review protected area networks to ensure they keep pace with the conservation needs of Smew and other species.

Aim 

Species are responding to climate change by changing their distributions, creating debate about the effectiveness of existing networks of protected areas. As a contribution to this debate, we assess whether regional winter abundances and distribution of the Smew Mergellus albellus, a migratory waterbird species listed on Annex I (EU Birds Directive) that overwinters exclusively in European wetlands, changed during 1990–2011, the role of global warming in driving distributional changes and the effectiveness of the network of Special Protection Areas (SPAs, EU Birds Directive) in the context of climate change. 

Location Europe. 

Methods 

We used site-specific counts (6,883 sites) from 16 countries covering the entire flyway to estimate annual abundance indices and trends at country, region (north-eastern, central and south-western) and flyway scales, inside and outside SPAs. We fitted autoregressive models to assess the effect of winter temperature on the annual abundance indices whilst accounting for autocorrelation. 

Results 

The Smew wintering distribution shifted north-eastwards in Europe in accordance with the predictions of global warming, with increasing numbers in the north-eastern region and declines in the central region. Trends in wintering numbers were more positive in SPAs on the north-eastern and south-western part of the flyway. However, a large proportion of the wintering population remains unprotected in north-eastern areas outside of the existing SPA network. 

Main conclusions 

SPAs accommodated climate-driven abundance changes in the north-eastern region of the wintering distribution by supporting increasing numbers of Smew in traditional and newly colonized areas. However, we highlight gaps in the current network, suggesting that urgent policy responses are needed. Given rapid changes in species distributions, we urge regular national and international assessments of the adequacy of the EU Natura 2000 network to ensure coherence in site-safeguard networks for this and other species.