Is breeding of farmland wading birds depressed by a combination of predator abundance and grazing?

摘要

Agri-environment schemes have been implemented across Europe to counter biodiversity loss in agricultural landscapes and halt the continual decline of farmland birds, including waders. Such schemes provide financial compensation for changes in agricultural practice, including livestock grazing regimes. Scheme uptake has been variable, partly because farmers believe that other factors, notably predation, are key to wader population declines. On the basis of wader breeding surveys across Shetland, UK, we show that predator density and livestock grazing, through reducing sward height, interact to influence territoriality and thereby are likely to affect wader breeding success. Our results appear to reflect views of both farmers and government agencies, which indicates that future agri-environment schemes would benefit from genuine stakeholder participation to maximize scheme uptake, implementation and beneficial effects on biodiversity. Our findings also imply that agri-environment schemes will reap the greatest benefits for waders through reducing stocking rate where avian predators are abundant.