Surviving swamps on South Australia’s parched Fleurieu Peninsula are a lifeline to wildlife – and farmers

South Australia is famously the driest state on the driest inhabited continent.

But even for South Australia, the current drought is extreme. Rainfall has been the lowest on record across large areas.

When drought strikes and water sources dry up, life becomes hard for wildlife. In these conditions, perennial water sources become enormously valuable.

Dotted across the drought-stricken Fleurieu Peninsula south of Adelaide are more than 850 swampy wetlands. When the landscape dries out, these swamps act as refuges. Animals, birds, insects and reptiles come from far and wide, drawn by permanent spring-fed water, good habitat, diverse plant species and cooler, more humid micro-climates. These swamps are vital habitat for the critically endangered Mount Lofty Ranges southern emu-wren.

Drainage channels were cut through many of these swamps in the early days of settlement, in an effort to turn them into pasture. The Fleurieu swamps are now considered an endangered ecological community. More than 90% of the remaining swamps are located on private property.

Keeping these swamps intact and restoring dried out wetlands comes with real benefits for farmers. Birds and insects seek refuge in the swamps, but feed on pest species on nearby farmland.

As drought tightens its grip on South Australia, these swamps will only become more important to wildlife. Restoring these swamps by bringing back the water and restoring plants and pollinators could go some way to help.

Important for nature – and humans

The swamps of the Fleurieu are some of the most diverse and productive habitats on Earth. Many species of plants, birds, frogs, fish, insects, mammals and reptiles rely on them to survive.

Before colonisation, swamps and wetlands covered large areas of the Fleurieu Peninsula. Three First Nations language groups lived in these areas on the central and eastern peninsula. The importance of these wetlands is recorded in the shared story of Tjilbruki, a Kaurna ancestor whose tears at the death of his nephew gave rise to six freshwater springs.

Over the last 200 years, most of this region has been cleared for pasture, crops and vineyards. Only 4% of the swamps are conserved. They are now listed as a critically endangered ecological community. These swamps are still declining due to threats such as more human settlement, land clearance, water extraction and invasive species such as blackberries.

Many were drained to make way for agriculture. We don’t fully know how many remain, as many are not well captured in current maps.

But we know these wetlands are vital, not just for nature but for farmers too. Farmers would miss them if they were gone.

We can see this most clearly during droughts. As the land gets drier and ephemeral water sources evaporate, ibises, eastern great egrets, white-faced herons and masked lapwings move into these swamps, seeking water. During the days, though, they spread out and feed on pasture pests such as grasshoppers and cockchafer beetle grubs.

Similarly, these wetlands act as a haven for important insect pollinators and predators. Hoverflies and native bees help farmers by pollinating pasture legumes such as clover, while predators keep down the numbers of pest species.

As adults, parasitic wasps rely on the nectar from swamp plants such as woolly teatree. But they lay their eggs on common pasture pests such as caterpillars and grubs. When their larvae hatch, they eat these pests. Carnivorous insects such as ladybirds and assassin bugs eat other insects which can trouble farmers.