The Aquatic Root Mat Communities of the Leeuwin-Naturaliste Ridge Caves
Western Australia - Threatened Species Day fact sheet
Stop these communities from caving in!
The rare and complex aquatic root mat communities of the limestone caves underneath the Leeuwin-Naturaliste Ridge in Western Australia are home to a rich array of wildlife. These communities are made up of freshwater crayfish, insects, crustaceans, water bears (tardigrades), rotifers (tiny aquatic organisms), mites, microscopic worms and fungi. They all live in the mat of eucalyptus and peppermint tree roots that come down through the soil in search of water from the permanent underground streams.
Found after a seven year search, the thick root mats, which provide a constant and abundant food source, sustain some of the richest faunal communities from groundwater caves anywhere in the world! More than 37 species have been found in four caves. At least half of these are newly discovered and many are yet to be identified.
Normally, caves don't support permanent life because they can't sustain a reliable food source. In these communities, the tree roots, which are able to reach the water found in the shallow caves, create a habitat for microscopic fungi. These fungi provide a food source for other organisms in the community which in turn provide a food source for predators. Parasites, scavengers, and debris-feeding organisms fill other roles in the community.
Major threats include the decline of the water level, destruction of the tree roots, and misuse or accidental damage to the roots. Other threats include the pollution of groundwater, cave collapse and possible introduction of species such as yabbies, which are thought to have had a serious impact on other root mat communities.
Illustration: Russell Shiel
Each of the four endangered communities covers a size of about 10 square metres and distances of 5.5 to 25 kilometres separate them. Each of the communities is unique and many of the species do not occur anywhere else in the world – some of them are restricted to one cave! The communities live in a warm, dark and wet environment – most of the species would not be able to survive anywhere else. Many of them do not have the ability to cope with drought and would die out if the water levels got too low.
The permanent water source provided by the streams is vital – the water attracts the tree roots, which provide the foundation of the community. Water quality can significantly impact on these communities, and this may be polluted by runoff from farms and urban developments which can contain toxins such as oil, grease, rubbish, heavy metal, pesticides and fertilisers.
Some of the recovery actions currently underway include: identifying and managing the catchments which feed the underground streams; ensuring that there is a permanent flow of water to the streams; and conducting research into the communities to develop a greater understanding of the way they work.
The trees that provide the root systems are being identified so that they can be protected from disease, and fire management regimes are being put in place. Regeneration in these areas will help provide more trees in the long term. Activities in and around the caves have been restricted, and an awareness program is being developed to educate the community about the unique beauty of the cave communities.
You can help protect Western Australia's aquatic root mat communities and other threatened species by:
- taking care when visiting national parks to keep your impact to a minimum;
- protecting the habitat of all our native species including the root mat communities; and
- supporting local efforts to conserve threatened species in your area by joining a local conservation, 'friends' or Bushcare group or by volunteering for Conservation Volunteers Australia.
For more information on helping threatened species in Western Australia contact the Threatened Species Network Coordinator:
Telephone: 08 9387 6444
You can also find out more information about Australia's threatened species by calling the Department of the Environment and Heritage's Community Information Unit on free call 1800 803 772 or by visiting the Department of the Environment and Heritage threatened species web site at www.environment.gov.au/biodiversity/threatened
The Pilbara Olive Python grows up to six metres long and is restricted to ranges within the Pilbara Region and some islands off the coast of Western Australia. Adept swimmers, the pythons utilise water holes to hunt. Their diet includes rock wallabies, fruit bats, ducks and Spinifex pigeons. Prey is captured by ambush on animal trails or by striking from a submerged position in waterholes.
The Nickol Bay Naturalists Club in Western Australia has received funding from the Threatened Species Network Community Grants Program to study the python's ecology. Volunteers from the club, together with scientists from the Western Australian Government, have attached radio transmitters to a number of snakes to obtain more information about their life cycles. Stephen Van Leeuwen, the President of the club, said 'They're not venomous but their jaws are designed to hang on tight to their prey so a bite would hurt. The main problem catching them is their sheer length and strength, since they attempt to coil around arms and legs to avoid being put into a bag!'