Sandy Shores

What are Sandy Shores?

Sandy shores are the coastal sandy connection between land and sea. They are dynamic ecosystems that are constantly moving. Tides, wind and waves move sand from one place to another, sculpting the shape of the shore into different types. These range from steep, narrow reflective beaches with coarse sand, to flat, wide dissipative beaches with fine sand. In between these are a range of intermediate types that are characterised by having sand bars in the surf zone, rip currents, or cusps (small hills on the beach). These different beach types are known as morphodynamic types. Because the dunes, beach and surf zone are so strongly connected, they are called the littoral active zone: the area where sand moves. Animals also move between these three zones, sometimes using one for resting and another for feeding. Therefore, sandy shores refer to the dunes, beach and surf zone as a single sandy unit.

Who lives on Sandy Shores?

Although beaches, dunes and the surf zone are all connected, they are home to different plants and animals that are adapted to the very different habitats in these ecosystem components. Further, the number and variety of organisms living on sandy shores is far more than meets the eye: over 500 different species have been recorded on South African sandy shores. Some are present in such high numbers that for every one-meter strip of beach between the dunes and waves, there are one million individuals of a single species. On average, in South Africa, there are about 100 beach animals bigger than one millimeter in the sand under your beach towel! Many of these species are unique to sandy shores, even unique to sandy shores in South Africa (endemic). This is because the environment is so harsh that the species have to be highly adapted to living where they do, and many species also have limited abilities to spread.

Because of the constantly moving nature of sandy beaches and the ebb and flow of salty tides, plants cannot grow on beaches; instead, they grow on nearby sand dunes where they play an important role in stabilising dunes. These dune plants are adapted for high temperatures, strong winds, salty conditions, low nutrients and minimal freshwater. Many of them are small and hold water in their leaves.

Terrestrial grazers like tortoises, grazing insects and even mammals like grysbok, steenbok and duiker can be spotted visiting healthy dune systems. Other mammals present in dunes include a variety of rodents, bushpigs, genets, porcupines, mongooses and monkeys. Dunes also provide food for interesting predators like caracal and gaboon adders, as well as smaller species, like spiders and beetles. Brown hyaena scavenge on wild beaches of the Atlantic coast although today these animals remain only in Namibia. Scavenging black-backed jackal are present in some South African dunes, e.g., in the Alexandria dunefield in Algoa Bay and at iSimangaliso in KwaZulu-Natal.

Even though it may not seem so, beaches are home to many different kinds of animals. Animals living on beaches either move about above the sand, live buried in the sand, or live in the spaces between the sand grains. Some species are big enough to hold in your hand, like ghost crabs, white mussels, plough shells and pill bugs; others are so tiny that you need a microscope to see them.

Although there are no plants on beaches, some species of algae live in between the sand grains, called microphytobenthos, on which some species feed. However, the amount of primary production from these tiny algal species is not enough to fuel beach foodwebs. Rather, beaches rely on nutrients from external sources, such as washed-up material from the sea or estuaries. When seaweed and kelp are washed ashore, it’s called wrack, and when dead animals are washed ashore, it’s called carrion. As a result, many species are scavengers, such as plough shells, ghost crabs, sand hoppers, beach hoppers and pill bugs. There are many predators too, such as some of the beach worms.

The abundance of invertebrate species on beaches provide food for lots of shorebirds, like gulls, plovers and sanderlings. Other bird species, such as Palm-Nut Vultures in KwaZulu-Natal also scavenge on beaches, and have been seen catching ghost crabs. Beaches and dunes also provide important breeding habitat for some shorebirds, including endemic species like African Black Oystercatchers, and sea turtles. Eggs laid on beaches, especially turtle eggs, are also an important source of food for beach animals.

The surf zone is that section of the shore that is under water and where waves are breaking. Both sand and water are constantly moving in this zone, so the animals that live here, especially where the sea meets the beach, have to be fast movers and able to burrow quickly in between waves. Some, like the white mussels and plough shells, surf with the waves and tides to maintain their position in this beach zone. Filter feeders grab tiny food particles from the water, such as white mussels, clams and other burrowing filter feeders like mole crabs (also known as sea lice). Fish such as moonies, mullet or harder, St Josef sharks and sand sharks also frequent the surf zone, as well as crabs like the three-spot swimming crab.

Phytoplankton in the surf zone also provide an important source of food for beach animals. This is especially on beaches where the phytoplankton, specifically surf diatoms, form accumulations that look like brown patches in the waves. The phytoplankton sticks to the surface of bubbles that form in the waves, where they photosynthesize during the day. They provide food for some species of fish, like mullet, as well as grazing beach mysid shrimps.

Why are Sandy Shores important?

Sandy shores include one of South Africa’s most valuable natural assets … beaches! They are special places to play, learn and are culturally and spiritually important spaces for many South Africans. They can be explored all along the South African coastline, attracting millions of visitors each year. Sandy Shores are also extremely valuable to humans by providing benefits in the form of essential ecosystem services.

Beaches are important for recreation and are a part of our South African way of life. Swimmers, surfers, anglers and families flock to beaches, particularly in summer. Visiting beaches is considered the most popular biodiversity-based tourism activity among both South African and overseas tourists. Investing in healthy beaches is an investment in the South African economy because they support tourism and coastal businesses.

Sandy Shores are critical nesting sites for valuable and threatened animals. Loggerhead and Leatherback turtles make their nests on the warm KwaZulu-Natal beaches. African Black Oystercatchers and sanderlings nest on beaches on all coasts. This provides important recreation, tourism and learning opportunities in the form of turtle tours and birdwatching.

Sandy shores are iconic sites for spiritual, religious and cultural practices and ceremonies. Beaches and saltwater are considered by many South Africans to be a place and product used for cleansing, healing, and spiritual renewal. Many South Africans visit the shore to connect with ancestors believed to reside in the water, and religious baptisms take place in the surf zone too. Visiting the beaches on certain days like New Year’s Day is also an important tradition in some cultures.

The plants and animals living on sandy shores and dunes provide us with food, medicine and materials and there are more than 220 useful plant species growing across the South African coastline. Coastal foragers have harvested dune plants, crabs, shells, and fish for thousands of years as food, traditional medicines and for use in rituals and ceremonies.

Healthy beaches and dunes provide ‘ecological infrastructure’ and are investments in our climate adaptation strategy. These ecosystems protect coastal communities by shielding them from rising seas and increased stronger storms because of climate change. Healthy dunes also protect coastal communities from extreme events like tsunamis.