EXPERIMENTAL EVIDENCE THAT VEHICLE TRAFFIC CHANGES BURROW ARCHITECTURE AND REDUCES POPULATION DENSITY OF GHOST CRABS ON SANDY BEACHES

摘要

Driving of off-road vehicles on beaches and coastal dunes is part of the recreational activity spectrum in many coastal areas. Although this practice can cause environmental harm, controlled experiments to test specific ecological impacts of vehicles are rare on high-energy shores. Here we use an experimental approach, where sections of a beach were repeatedly driven over by a vehicle, to demonstrate effects on ghost crabs (Genus Ocypode) inhabiting a beach in eastern Australia. Vehicle traffic caused a significant reduction in crab burrow density by 66 % and the remaining burrows were smaller by 22 %, suggesting impacts on both population size and structure. Crabs also responded behaviourally to vehicle disturbance by altering their burrow architecture to simpler and deeper forms. Experimental data from this study not only add to a growing body of evidence highlighting deleterious environmental effects resulting from recreational vehicle use, but clearly demonstrate that environmental harm is a direct and undisputable consequence of vehicle traffic on beaches. This brings into focus the need to implement visitor management strategies that meet conservation targets without dismissing the social, cultural and economic dimensions of vehicle-based recreation.