Seabird breeding populations decrease along the arid coastline of South Africa’s Northern Cape province

Abstract

Numbers of eight seabird species that have bred in coastal areas of South Africa’s arid Northern Cape province have all shown substantial decreases since initial estimates of their abundance were made in the latter part of the twentieth century. Likely drivers of these decreases include reduced availability of food and the loss of suitable breeding habitat, including in the Orange River Estuary and at coastal pans and islands, which has resulted from a variety of human alterations, uses and disturbances. The decreases have contributed to a worsening conservation status of several of the seabirds, some of which are endemic to southern Africa. The more adaptable species appear to have partially offset habitat loss by moving to alternative breeding sites. However, substitute habitat is limited and the more numerous species suffered relatively large decreases. In order to conserve remnant populations it will be necessary to prevent further loss of breeding habitat, restore some former habitats and provide suitable, alternative habitat.

Keywords: conservation, cormorants, gulls, habitat degradation, population decreases, terns