ISLANDS
Islands are important ecosystems because of their isolation from land. Protected from land based predators, birds and seals often gather on islands in spectacular breeding colonies to raise their young. The nutrient input from these animals in the form of guano (bird droppings) and other animal waste products influence the ecology of islands and their shores. For example, increased nutrients around islands increases productivity reflected in more seaweeds, more, bigger and faster growing limpets and in some cases more west coast rock lobster. Historically guano was harvested for fertiliser (before artificial or synthetic fertilisers were produced). The removal of guano was a key threat to seabirds such as the iconic and Endangered African penguin, whose numbers are now at only 2% of original population estimates. Historically, egg harvesting also played a role in the decline of penguins, however, in more recent years changes in the distribution and decreased abundance of forage fish are the major concern for penguins. Pressures on islands include alien species and predators, climate change and overfishing. Well managed islands have effective management of invasive and potential predators and disturbance and other risks to breeding birds are minimised.
Robben and Dassen Island are two of the most important seabird islands on the west coast and although penguin numbers on these islands have declined, these are now the largest penguin colonies on the west coast. Within the West Coast National Park, Malgas Island is home to a large gannet colony. Seal Island in False Bay is world famous for the hunting behaviour of the great white shark, whose aerial displays provide incredible images for photographers from around the world. Bird and St Croix Islands in Algoa Bay are now critically important seabird areas, with St Croix hosting the largest African penguin colony in the world and Bird Island holding the world record for the largest gannet colony.
Important islands will be protected in Robben Island MPA and Addo Elephant National Park MPA.
