Effects of changes in agricultural landscape on a breeding population of linnets Acanthis cannabina L. living in adjacent heathland Original Research Article

The effects of a land consolidation project were studied in an agricultural landscape in Brittany on the foraging habitats, breeding parameters and factors causing breeding failure of the linnet Acanthis cannabina L. The study covered five breeding seasons before land consolidation and another five afterwards. The project involved the disappearance of more than 50% of the hedgerows, and about 30% of the meadows and fallow lands were replaced by cultivation. Before land consolidation, breeding success was mainly affected by density-dependent factors, whereas afterwards density-independent factors such as weather or disease played an important role. The preferred feeding sites remained the same during the whole study period; fallow lands, rape fields and meadows were selected positively but cereal and potato fields were avoided. This characteristic became more apparent after land consolidation, because it involved a reduction in the feeding areas of the linnet. Numbers of eggs per clutch, hatchlings and fledglings were unaffected but fledging and breeding success of the first brood increased significantly during this period. Predation, which was the main cause of egg loss and nestling mortality, decreased significantly after land consolidation, through loss of hedges used as movement corridors by some specialist predators. The increase in the distance between breeding site and foraging area probably reduced the time spent by adults on their nests, leaving nestlings unprotected.