The use of predator-exclusion fencing as a management tool improves the breeding success of waders on lowland wet grassland

Abstract

Waders breeding on lowland wet grassland have undergone dramatic declines across Europe in recent decades. Few species now achieve the levels of breeding success required for population stability and recovery, with predation from large mammals acting as a key compounding factor limiting nest survival and productivity. Predator management through lethal control is often controversial, yet alternative non-lethal methods are little tested in the context of grassland breeding waders. Excluding predators through the use of electric fences has led to improvements in nest and chick survival in other habitats. To test the applicability of this method to lowland wet grassland we constructed predator-exclusion fences on sites across the UK and, with Lapwing Vanellus vanellus as a study species, used historical and contemporary data to test whether excluding large mammalian predators leads to an increase in wader nest survival and productivity, and whether effects differ between fence designs. Lapwing nest survival was significantly higher in the presence of any type of predator-exclusion fence, with significantly fewer nests predated each day. Overall productivity also improved, with significantly higher numbers of chicks fledged per pair in years when fences were operational. Different designs and methods of powering fences resulted in different levels of success, with combination design fences and those powered by mains electricity performing best. Excluding large mammalian predators from areas of lowland wet grassland with predator-exclusion fencing successfully improves Lapwing nest survival and productivity, allowing breeding success to exceed the levels required for population recovery. Other wader species breeding in the same habitat are also likely to benefit from the increased protection from predation provided by fences. Predator-exclusion fencing is therefore an effective management tool for protecting restricted and declining populations of breeding waders on lowland wet grassland.