A coastal sandhill survives in one of the harshest environments on land, shifting sand, salt spray, strong winds, heat & very few nutrients. Everything that lives there has a job in holding the dune together.

On Dawesville’s dunes, pioneer plants such as beach spinifex, pigface & coastal wattles are the first line of defence. Their roots bind loose sand, their leaves slow the wind, and their bodies trap drifting grains. Behind them, secondary shrubs & small trees deepen the root network and add organic matter, slowly turning bare sand into something closer to soil.

Less visible, but just as important, are the microbial communities (fungi, bacteria and cyanobacteria) that form thin crusts on the sand surface. These crusts help stabilise the dune and begin the long process of building fertility. Invertebrates like ants & beetles aerate the sand and move nutrients around, while birds & reptiles use the dunes for nesting and shelter, adding more nutrients through their droppings.

Together, these plants, microbes & animals create a living skin over a moving skeleton of sand. When that skin is intact, the dune traps more sand than it loses. When it is damaged, the dune starts to shrink.

How sandhills form & change over time

Sandhills are shaped by wind, but biology decides whether they stay put or blow away. As wind carries sand inland from the beach, pioneer plants slow the air at ground level, causing sand to drop and accumulate around them. Over time, this builds the foredune (the first ridge behind the beach).

As the dune becomes more stable, more plant species move in, root systems deepen & the dune grows in height and width. Between dune ridges, low areas called swales form. These swales are not empty spaces, they are part of the dune system and often hold important vegetation & wildlife habitat.

On the Swan Coastal Plain, including Dawesville, this process has created a series of dune systems over thousands of years. But while the older inland dunes change slowly, the young coastal sandhills can change noticeably within a decade when their biology is disturbed.

Vehicle access & the shrinking of Dawesville’s sandhills

Many residents have noticed that the sandhills near popular access points have become lower and more eroded. One key reason is repeated vehicle access, especially four-wheel drives travelling through the gaps between dunes to reach the beach.

When a vehicle drives through the swale between two sandhills, its tyres crush the vegetation at the base of each dune. This vegetation is what traps sand and stops it blowing away. The roots that stitch the dune together are broken, and the thin microbial crusts on the sand surface are destroyed. What was once a stable, living surface becomes loose, exposed sand.

Once that biological skin is broken, wind has a clear pathway to lift and remove sand from the sides of both dunes. The gap between the dunes widens, the dune faces become steeper and then lower & over time the two sandhills flatten. The dune system shifts from being a sand trap to a sand source, feeding erosion instead of resisting it.

This damage does not happen in a dramatic landslide. Instead, the dune shrinks grain by grain. Height is lost from the crest, width is lost from the sides & the overall volume of sand decreases. What used to feel like a substantial hill can, within a few years, become a low, degraded mound.

Dawesville as an erosion hotspot

The Dawesville - Mandurah coastline is recognised as an active erosion hotspot. In practical terms, this means dunes here are losing sand faster than they can naturally rebuild. Storm surges bite deeper into the foredunes, wave energy is concentrated on already weakened sections & vegetation struggles to re-establish between events.

Climate patterns over the last decade have added extra pressure. More frequent and intense storms, longer dry spells that stress dune plants & increased recreational use of the coast. All of these factors combine to make dune shrinkage visible within a single generation.

For locals who have walked the same tracks for years, the change is obvious. Places that were once sheltered behind tall sandhills now feel exposed. Access points that used to be narrow paths through healthy vegetation have widened into bare, sandy corridors.

Why shrinking sandhills matter for the community

When sandhills shrink, the impacts are felt well beyond the beach. Dunes act as natural buffers, absorbing wave energy & protecting roads, homes & community infrastructure from storm damage. Lower, narrower dunes provide less protection, increasing the risk of flooding and erosion further inland.

Sandhills are also biodiversity hotspots. Even though they can look sparse, they host specialised plants, insects, reptiles & birds that are adapted to dune life. As dunes flatten and vegetation is lost, these species lose habitat & the ecological corridor along the coast becomes fragmented.

There is also a cultural & social dimension. The sandhills are part of Dawesville’s identity - the backdrop to walks, fishing trips, family outings & everyday views. Watching them shrink can feel like losing part of the place itself.

Rebuilding the dunes: restoring the living skin

The good news is that sandhills can recover, but only if their biology is given a chance to rebuild. Effective dune restoration focuses on protecting & re-establishing the living skin that holds the sand in place.

Common approaches include fencing off damaged areas to keep vehicles & heavy foot traffic out, laying brush matting to create a rough surface that traps sand & planting pioneer species such as spinifex, pigface & coastal wattles. As these plants take hold, they begin to trap more sand, rebuild dune height & provide shelter for other species to return.

Community involvement is crucial. Local groups, schools & residents can help with planting days, monitoring dune condition & sharing information about why staying off the dunes - including the swales between them - makes such a difference. Framing this as a shared care story, rather than blame, helps build pride & ownership in the recovery process.

Telling the sandhill story through Connecting Corridors

The shrinking of the sandhills is both a warning & an opportunity. It is a chance to explain, in clear language, that dunes are living systems. The sand moves, the plants hold, the microbes build & the animals enrich. When that system is respected, the coast is stronger. When it is repeatedly disturbed, the dunes shrink & the whole community feels the impact.

By sharing local observations, photos over time & stories of restoration, Dawesville can turn concern into action. The sandhills may have shrunk, but with care, they can grow again.