The city of Durban boasts a wealth of coastal resources along its 97 km of coastline. These include rocky shores, mangrove forests, coral reefs, coastal forests, wetlands and sandy beaches. Of these, the least studied and most underappreciated are sandy beaches. It has often been pointed out that it is these neglected ecosystems that will ultimately bear the brunt of change. Rapid population growth and the associated increase in the demand for coastal infrastructure has lead to the excavation of sandy beach and dune systems in favour of development. This is made worse by climate change and associated impacts which include sea level rise and an increase in the frequency and severity of storms.
Threats to Durban’s Sandy Beach Ecosystems
Climate change: Threatens beach systems from the seaward side due to predicted increase in the severity and frequency of storms, and sea level rise. Storms will further erode beaches and sea level rise will drown them.
Coastal infrastructure and development: Together with sea level rise, encroaching developments result in beaches being trapped in a coastal squeeze. Beaches would normally migrate landward in response to sea level rise but these hard structures mean that beaches have nowhere to go. Navigational channels and pipelines built at sea also disrupt sediment movement, negatively impacting beach ecosystems, increasing beach erosion.
Shoreline armouring and erosion: As humans continue to build on dune systems, we face the growing problem of erosion. To counteract this, we build seawalls and groins. These structures further stress the beach ecosystem by disrupting the natural sand movement processes. This is going to become a larger problem as we start experiencing the effects of climate change.
Beach nourishment: As beaches erode and coastal property gets threatened, humans try to prevent this by adding sand to the beach. Beach nourishment, if done incorrectly, can be detrimental to the animals that live on the beach.
Sandwinning and dam construction: Upstream impacts like sandwinning (the removal of topsoil) and the construction of dams may contribute to the loss of beaches by robbing the beach of sand carried down by river systems.
Resource exploitation: The unsustainable harvesting of beach organisms negatively impacts coastal food webs.
Pollution: Agricultural, domestic and industrial pollutants from upstream ultimately end up on the beach and in the sea.These are harmful to marine life, often resulting in decreases in biodiversity and the disruption of ecosystem functioning.
Grooming and cleaning: Mechanical cleaning of beaches provides a beach free of rubbish and improves its aesthetic appeal but it also severely disrupts natural ecological processes.Removing wrack deprives the beach of an essential habitat. Wrack also assists in the growth of dunes by stabilising windblown sediment.
Recreation and tourism: Damage to organisms through trampling and off-road vehicles.
Because we’ve taken these systems for granted for so long, it is difficult to fully understand the ramifications of losing them. Not only will we lose a unique and poorly understood biodiversity but also critical and irreplaceable ecosystem services. Results of a comprehensive study on Durban’s beaches are compiled in the report Durban’s Beaches – more than just sand.