Testing the effects of recreational disturbance on two upland breeding waders

Previous work has shown that Golden Plovers Pluvialis apricaria guarding chicks utilize heavily disturbed habitat at a lower rate than surrounding areas, but that such rates of avoidance are reduced when the movement of people is restricted to a surfaced footpath. However, there remained some unanswered questions, which are addressed in this paper. First, we examine to what extent habitat avoidance is dependent upon visitor numbers, and find no evidence that Golden Plovers avoided disturbed areas at a site where visitor pressure was half that previously studied. Secondly, we examine whether these relationships between habitat occupancy and disturbance apply to other upland waders and find that Dunlin Calidris alpina habitat utilization in disturbed areas showed a non-significant increase of approximately 50% following the provision of a surfaced footpath, in a manner similar to that observed for Golden Plover. Thirdly, we examine whether the large numbers of visitors (120 per weekend day) using the surfaced footpath impact on Golden Plover breeding success, despite the lack of habitat avoidance. There was no evidence that nest location, clutch survival or chick growth rates were reduced close to the footpath. Together, these results suggest that high levels of disturbance can impact upon habitat usage by upland waders, but only in limited circumstances where visitor pressure is very high (greater than at least 30 visitors per weekend day). However, access to such areas can be permitted for large numbers of visitors without impacting upon wader reproductive performance through the provision of a well-surfaced route.