干旱区生态环境知识资源中心

Because resources and funds available for the conservation management of many threatened species are limited, it is important to determine the effectiveness of different conservation measures aimed at protecting threatened species. The globally Near Threatened Damara Tern Sterna balaenarum breeds on anthropogenically disturbed beaches on the central coast of Namibia. We assessed the effectiveness of conservation measures on the breeding numbers, densities and success of Damara Terns in a loose colony among small barchan dunes on the central Namibian coast. Nests were monitored daily during the 2001/02 and 2002/03 breeding seasons. Information notices were erected during the 2001/02 breeding season and vehicle access was restricted to prevent human disturbance in the colony during the 2002/03 season. Nest numbers and density doubled in the second season, but breeding success decreased significantly from 83% to 67%. This unexpected result probably arose from increased densities attracting more predators. Despite this decrease the protection measures increased the number of chicks hatching from the area by 71%. In conjunction with two previous studies of protection from off-road vehicles we conclude that Damara Terns benefit from reduced disturbance and prefer to nest on undisturbed beaches.