Ghost crabs as a tool for rapid assessment of human impacts on exposed sandy beaches

On exposed sandy beaches, the destruction of sand dunes and intense recreational activities are often the most common anthropogenic disturbances. It was proposed that such disturbances should have important effects on animals such as ghost crabs. Numbers of burrows of ghost crabs, Ocypode cordimana, were compared between urban and non-urban beaches at different levels on the shore. Overall, there were more burrows at high levels near sand dunes. There were significantly fewer burrows at high levels on urban than on non-urban beaches. These differences are discussed in terms of destruction of habitat and possible changes in behaviour of crabs. This study suggests that the world-wide genus Ocypode may be useful as a tool in rapid assessment of human impacts on exposed sandy beaches.