Salt exploitation and landscape structure in a breeding population of the threatened bluethroat (Luscinia svecica) in salt-pans in western France

The Guérande salt-pans represent the main French breeding area of bluethroat, a migrating passerine. Salt exploitation has created a geometrical artificial landscape in which we investigated factors influencing spatial distribution and breeding success of this species using a Geographical Information System. We compared data for four sites in these salt-pans, for three zones in the most densely populated site, and for 2500 m² grid cells defined for this same site. This study showed the influence of (1) the level of salt exploitation activity, (2) the density of bank intersections, (3) the extent of area covered by Suaeda vera bushes and (4) the structural heterogeneity. The continued management of these salt-pans enhanced bird breeding success. Thus, traditional salt exploitation contributes directly to the conservation of bluethroat, considered as an endangered species in Europe.