Cave Dwellers & Underground Guardians of the Margaret River Region

There can’t be many places in the world where the sights below ground are as breathtaking as those above, but that’s exactly the case in the Margaret River Region. With numerous highly decorated limestone caves lying beneath the surface of the Leeuwin Naturaliste Ridge, it’s fair to say that if you’re a cave lover, you’ve come to the right place.

Formed over millions of years, a few of these complex and fragile karst systems are open to the public, providing an extraordinary natural attraction for visitors to the region.

There are four tourist caves under the purview of the Margaret River Busselton Tourism Association, and cave specialist Peter Bell heads up the group of behind-the-scenes defenders whose brief is to care for and preserve the caves for future generations.

“We are responsible for the conservation and preservation of the caves and their precincts, including all the associated flora and fauna,” he says. “It’s our role to make sure we don’t cause detriment to the sites, ensuring they’ll be preserved for future generations to visit.”

They’re certainly a magnet for visitors, attracting many thousands of would-be cavers every year, keen to experience Lake Cave’s permanent lake, Jewel Cave’s enormous chambers and record-breaking stalactites, Mammoth Cave’s awe-inspiring scale and Ngilgi Cave’s torchlight adventure tours.

Cave tours range from completely easy ‘at your own pace’ self-guided tours, guided tours along boardwalks with informative commentary to ‘off piste’ adventure hard-hat tours.

Peter has been involved in cave management since 1992, and has been an avid cave enthusiast for many years.

Thanks to soluble limestone environment of the Leeuwin Naturaliste Ridge, the whole area is a patchwork of cave-friendly geography known as karst. Millions of years of rainwater seeping through the soluble rock has created a network of extraordinary underground treasures which, by their nature, need careful tending to minimise the impact of human and other outside influences, such as pollution.

It’s worth bearing in mind that every time a visitor sets foot inside one of the caves, the cave is affected by their presence.

“Every time we’re in there, even just breathing, affects them. Lint, hair, skin and dust all have an impact on the cave’s make up.”

And as the caves are open 364 days a year, with some 40,000 visitors passing through annually, that’s a lot of lint, hair, skin and dust that can build up over time.

“We tackle that by our own regular baseline maintenance,” says Peter. “Every three months we embark on a vacuuming program, cleaning every boardwalk carefully.”

That’s a lot of boardwalks to vacuum and at one site, over 12.5kg of dust was collected. If dust was allowed to accumulate, the impact would be detrimental to the ongoing ‘health’ of the caves, so to augment the vacuuming program Peter and his team have designed an innovative little dust ‘diaper’ to sit under all the staircases, collecting falling dust and dirt before it reaches the cave floor.

“Dust is our greatest enemy,” says Peter. “It’s mobile and can cover cave walls as well as the floor. We’ll use mist wands with pure filtered water over the straw formations to keep them dust-free too.”

In their ongoing battle against dust, Peter accepts that the team’s role is rehabilitation rather than restoration.

“We compare and document the caves to look at changes between the present day and the past. We encourage staff to talk to visitors to inform them of our work, to explain reasons and promote the importance of cave conservation.”

Bigger projects are on the horizon too, including an update of the lighting at the popular Ngilgi Cave at Yallingup.

“We’ll be bringing it in line with other sites – lighting is a key component in a cave experience, and the Margaret River region has led the way in this field of visitor attractions. All the systems are fully digital and carefully control the lighting levels in what would otherwise be a completely dark environment.”

With too much light, plants and algae start to grow in the cave which changes the cave’s appearance and causes damage to the natural formations.

“We take inspiration from around the world but by the very nature of our isolation we have to resolve problems innovatively,” says Peter. It’s a far cry from the earliest days of cave exploration which relied on kerosene candles to light the way.

“Lake Cave and Mammoth Cave are on their third lighting system,” says Peter. “It’s such a harsh environment for electricity and water to co-exist.”

Other recent challenges include a mysteriously vanishing lake which threatened the rare aquatic fauna in Lake Cave.

Between 2004 and 2014 the water levels in Lake Cave dropped by almost half a metre, putting the future of the cave’s remarkable subterranean aquatic cave fauna, called stygofauna, at risk and reducing the scale of the cave’s iconic crystal reflections. The size and speed of this decline was unprecedented in the cave’s recent history and there was no clear reason for it.

In 2010, the Margaret River Busselton Tourism Association initiated the Lake Cave Eco-hydrology Recovery Project, which successfully gathered and analysed a wealth of scientific data on the cave. The project implemented strategies for slowing the decline in the water level, and catalogued the incredible diversity of stygofauna in the cave. The Lake Cave stygofauna are the microscopic aquatic organisms that live in the cave and they survive by eating anything that comes their way – decomposing insects, tree roots, even human skin particles that naturally fall from visitors in the cave. Most of them are less than a millimetre long, some of them have become cave adapted, have no eyes and lost all pigmentation, and may even be unique to Lake Cave.

After some limited initial success in slowing the water level decline in the cave with some of the project strategies, Mother Nature took over in March 2014 when the water level started to rise sharply, for no apparent reason.

The water level is now right back up to its normal historical level. The reflections are stunning and expansive once again, and there’s now a valuable bank of data that will help the team work out the possible causes or hydrological cycles that might be affecting Lake Cave.

Changing rainfall patterns are one factor affecting the cave, but thanks to ongoing research it’s possible to work out whether there are any additional factors at play. There’s something comforting about the eternal nature of caves, charting passing fires and floods; a paleo subterranean record of seasons from long ago, a natural reflection of the region’s ever-changing landscape.

• Jewel Cave – The largest show cave in Western Australia, entering Jewel Cave is like finding yourself inside a lofty natural cathedral.
• Lake Cave – Enter this crystal wonderland via steps descending into a giant sunken entrance among ancient Karri trees.
• Mammoth Cave – This natural time capsule offers an extraordinary insight into Australia’s ancient past
• Ngilgi Cave – This exquisitely decorated cave was Western Australia’s first tourist attraction.