Understanding the impact of recreational disturbance caused by motor vehicles on waterbirds: a case study from the Bundala Wetland, Sri Lanka

Abstract

Promotion of recreational access is an important strategy that helps to impart conservation values to wetlands and aids in fostering sustainable employment for local communities who live in close proximity to wildlife habitats. Unregulated recreational vehicles in coastal wetlands can cause detrimental impacts on coastal avifauna. There is a dearth of information especially in the South Asian context on the impact of recreational disturbance to waterbirds that can inform the management of wetland destinations. This study examined the response of selected water birds to motor vehicles using multispecies experimental disturbance trials conducted at Bundala National Park, Sri Lanka; a Ramsar-listed wetland of global importance. The selected species had signifcantly diferent sensitivities to disturbance caused by motor vehicles (log-rank test, χ2=51.7, P<0.05). The probability of a bird responding to a moving vehicle parallel to the bird at a distance of 75 m was greater than 0.6 for all selected species (Calidris minuta, Charadrius alexandrinus, Himantopus himantopus, Limosa limosa, Platalea leucorodia and Mycteria leucocephala) except Hydroprogne caspia. Resting birds appeared to be more afected by recreational disturbance when compared to foraging birds. Larger birds (height of adult bird: 80-105 cm) were more sensitive to recreational stimuli, compared to smaller birds (10-20 cm). In general, responses of birds for recreational stimuli, were prominent up to 100 m from the source. Selected waterbirds showed longer response distances in habitats exposed to high vehicle trafc activity suggesting possible habituation of birds to recurring disturbance. Our fndings suggest a minimal setback bufer of 100 m needs to be employed to manage recreational disturbance from motor vehicles at Bundala National Park.