Pressures on coastal biodiversity in South Africa: a cross-realm review

Abstract

South Africa’s coastal zone comprises diverse ecosystems and species, and provides important benefits to people. It is also under significant pressure from numerous activities that take place on land, in estuaries, and in the sea, and that are rarely considered together. Here, we review the pressures on coastal biodiversity in South Africa, taking a cross-realm perspective. The pressures are reviewed under 10 themes: biological resource use; energy production and mining; pollution; coastal development; transportation and service corridors; natural systems modifications (sand-flow disruptions, estuarine hydrological regime change, livestock grazing and browsing); human intrusions and disturbance; aquaculture, agriculture and plantation forestry; invasive and other problematic species and diseases; and climate change, severe weather and ocean acidification. Many of these are intense or pervasive cross-realm pressures, often with cumulative, synergistic impacts that are collectively causing habitat fragmentation and loss, declines in species richness and abundance, altered animal behaviour, reduced ecosystem resilience, and declines in capacity to provide ecosystem services. However, the inter-connected nature of these pressures also means that integrated coastal management provides opportunities to address multiple pressures and impacts cross-realm. Sustainable development that is mindful of long-term climate projections is imperative in the coastal zone to safeguard this national asset into the future.