SummaryForest ecosystems in South Africa are at risk from a variety of anthropogenic threats impacting the faunal species dependent on them. These impacts often differ depending on species-specific characteristics. Range data on forest dependent bird species from the South African Bird Atlas Project (SABAP1 and SABAP2) were analysed to determine links between deforestation, species characteristics and range declines. Half of the species studied were found to have declining ranges. Range change data for these species were correlated with data on changes in land cover from 1990 to 2014. To determine which land cover changes affect extinction, occupancy was modelled for 30 sites across South Africa which experienced a loss of more than 10 species. Most species lost were birds of prey or insectivores. Indigenous forest decreased in 17% (n = 5) sites, while plantations/woodlots decreased in 60% (n = 18) sites. Occupancy modelling showed extinction to be mitigated by plantations in 6/28 species, and forest expansion mitigated extinction in 7/28 species. Responses to deforestation did not appear to be related to particular species characteristics. Half of South Africa’s forest-dependent bird species have declining ranges, with the loss of these species most prominent in the Eastern Cape province. Four responses to changes in forest and plantation cover are discussed: direct effects, with forest loss causing species loss; matrix effects, where plantation loss resulted in species loss; degradation of indigenous forest; and the advent of new forest arising from woody thickening caused by carbon fertilisation, which may not result in optimal habitat for forest-dependent birds.

No abstract

Island species are susceptible to extinction through disturbances such as habitat transformation. Due to the small size and isolation of islands, species have limited options for refuges and recolonization, making their rehabilitation a conservation priority. Robben Island is a continental island, isolated from the mainland ca. 15 000 years ago, and has been degraded by humans and alien species for nearly 400 years. Mainland areas with similar vegetation should be good reference sites for the biological restoration of the island due to historical connectedness. However, very little information exists as to which species were lost. Here we aim to identify the best mainland sites to use as reference sites for Robben Island based on remaining arthropod diversity on the island. Sites found to be most similar in terms of arthropod diversity to Robben Island were sites north of Robben Island (Elandsbaai and Dwarskersbos) rather than the geographically closest locations. These sites therefore represent ideal reference sites for biological restoration of the island. We do not suggest the reintroduction of species from these localities, but rather Robben Island should be restored to match their vegetation height and cover.