Bare soil as a staple commodity for declining ground-foraging insectivorous farmland birds
1 Institute of Ecology and Evolution – Conservation Biology, University of Bern, Switzerland
2 Swiss Ornithological Institute, Valais Field Station, Switzerland
* Email: raphael.arlettaz@nat.unibe.ch
Changes in cultivated habitats and intensification of agricultural practices are the main factors responsible for the widespread decline of farmland birds across Europe. The goal of agri-environment schemes is to restore farmland biodiversity. Yet, these schemes have so far only had moderate effects upon farmland avian biodiversity, especially with respect to ground-feeding insectivorous birds. Using radio-tracking, we investigated micro-habitat selection in five farmland birds of Switzerland (Wryneck, Hoopoe, Woodlark, Common Redstart and Ortolan Bunting) that occur in fruit plantations and/or vineyards. Habitat characteristics were recorded around foraging locations and compared with non-visited habitat within individual home ranges. The data were analysed using a hierarchical logistic regression model implemented in the Bayesian framework using Markov chain Monte Carlo (MCMC). In all species, and irrespective of habitat type, the availability of bare ground (with cover optima ranging from 30% and 70%, depending on species) appeared to be the principal determinant of foraging occurrence. These results suggest that the conservation and restoration of populations of endangered ground-feeding insectivorous birds requires the creation of patches of bare soil among arthropod-rich grassland. Extensification of grassland management and/or targeted removal of grass-cover locally may represent adequate management solutions. We recommend these measures to be integrated into future agri-environment policies.
Raphaël Arlettaz’ scientific background is in population biology, community ecology, eco-physiology and behavioural ecology. Since his nomination at the head of the first chair of Conservation Biology in a Swiss University (2002), Raphaël Arlettaz has re-oriented his research activities towards applied conservation biology and restoration ecology, with a major focus on endangered species of farmland and alpine ecosystems. Raphaël Arlettaz also leads a field station of the Swiss Ornithological Institute in the Alps of Valais, a biodiversity hotspot. His double mandate enables him to develop integrated conservation and restoration programmes, from research activities (university) to population monitoring and implementation of corrective conservation/restoration measures (ornithological institute), so as to bridge the gap between research and action.
