How Habitat Features and Human Activities Shape Occurrence of the Declining Eurasian Oystercatcher Haematopus ostralegus on a Mediterranean Coastline

Summary. Understanding ecological factors and processes affecting the abundance of species of conservation concern is key to ensuring their conservation. The Eurasian Oystercatcher Haematopus ostralegus is a ‘Near Threatened’ wader species that depends on coastal zones during the non-breeding season. However, these habitats constitute focal points of human settlement and suffer from intensified human activities. I used survey data from the central part of the Gulf of Gabès, Tunisia, to assess the significance of ecological and anthropogenic factors as predictors of the density of wintering oystercatchers. Using generalized linear mixed models, Oystercatcher density was positively correlated with sediment mud content and negatively correlated with seagrass cover. Density was also positively correlated with distance from human settlements and negatively correlated with the densities of recreationists and artisanal fishermen. Overall, oystercatchers avoid intertidal areas near human settlements. This study provides critical information on where conservation and research efforts should be focused to preserve this wader species. As a priority, investigations on flight initiation distances are needed to determine at which spatial level it would be beneficial to create buffer zones or walkways to minimise the negative impact of human disturbance on this wintering population.— Hamza, F. (2020). How habitat features and human activities shape occurrence of the declining Eurasian Oystercatcher Haematopus ostralegus on a Mediterranean coastline. Ardeola, 67: 269-284.