Species distribution shift challenges conservation of a European farmland bird

Rolland S.(1), Eraud C (2), Roux D (2), Jiguet F (1)

1 Centre d’Ecologie et des Sciences de la Conservation, UMR 7204 MNHN-CNRS-UPMC, 55 rue Buffon CP51 75005 Paris

2 Office National de la Chasse et de la Faune Sauvage,79360 Villiers en Bois, France

Climate change is increasingly becoming a major threat to biodiversity. In this context, some species are more likely to be vulnerable to these changes. For example, most birds are currently forced to shift their breeding range to track climate, but migrant birds have to face additional threats during migration and overwintering period. Climate and weather conditions are then key factors to survival.

Our case study here is Eurasian skylark, a common farmland bird declining in Europe. As for other bird species overwintering in Europe, we expect its wintering distribution to shift northwards in relation to warming winters due to climate change.

We used a Bayesian hierarchical model with INLA method to characterize the thermal niche of wintering skylarks and their spatial distribution in France between 2000 and 2014, covering the whole country with

5,000 point counts repeated annually. We found that distribution at wintering grounds has globally shifted northwards during the study period. However, we could not find significant evidence that birds have moved to initially colder regions.

The observed shift is most likely resulting from a global reduction in migration distance, which means that the proportion of birds migrating to southern Europe is declining. Nevertheless, potential interactions between climate change and other environmental or anthropic factors should be investigated to preserve Skylark wintering in this region. These results may be valid for other farmland bird species wintering in Europe, as such conservation measures aiming at improving wintering conditions for these birds should take into account these changes in distribution.