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Unknown wonders: Barmah-Millewa forest

Australia is famous for its natural beauty: the Great Barrier Reef, Uluru, Kakadu, the Kimberley. But what about the places almost no one goes? We asked ecologists, biologists and wildlife researchers…

The Barmah-Milewa forest is an ephemeral landscape of unique biodiversity. Flickr/Parks Victoria.

Australia is famous for its natural beauty: the Great Barrier Reef, Uluru, Kakadu, the Kimberley. But what about the places almost no one goes? We asked ecologists, biologists and wildlife researchers to nominate five of Australia’s unknown wonders.

At first glance, the Barmah-Millewa forest may not seem all that impressive. If you’ve come in a dry year, via the main roads, you may find yourself on a river bank that does not look that much different to other parts of the Riverina.

But if you return on a wet year, when the forest is transformed into a swamp and teeming with birds, or if you could watch the landscape change over time through floods and droughts, you might see why the Barmah-Millewa forest is a Ramsar site (a wetland of International Importance), one of six icon sites in The Living Murray initiative, and has recently been declared a national park.

Barmah transformed during a wet year. Flickr/Parks Victoria

Wet beginnings

About 20,000 years ago, a geological event lifted a large area of land, blocking the Murray River. A huge lake was formed, and the river changed direction, flowing north and south around the uplifted land.

The narrow river channel at this point ensured regular flooding of the surrounding plains, creating a unique set of wetland habitats. Known as the “Barmah choke”, this is the narrowest part of the Murray River. When the Goulburn River is in flood, the Murray can actually run backwards at this point for up to 50km, all the way back to the Edwards river.

Biodiversity

Barmah is best known as the home of the largest population of River Red gum trees in the world. Flickr/barmahmillewacollective

This unique geology supports a wide range of habitats. There are several lakes, swamps, and Moira grass plains. Red gum trees lie on the floodplains, Black box trees on the high ground, and sand hills covered with Callitris pines. The ecological diversity supports an impressive array of biodiversity, including 553 native plant and 273 native animal species.

A large number of birds - such as Spoonbills, Egrets, Cormorants and Ibis - flock to the wetlands. Barmah-Millewa is an important breeding area for rare species such as the Superb parrot, Freckled duck and Latham’s snipe.

There are also plenty of fish in the area, including the iconic Murray cod. Three species of crayfish coexist by separating themselves according to habitats: Murray crayfish hunt in the river, yabbies crawl around the lakes, and Swamp yabbies dig in the floodplains.

Barmah acts as an important area for local wildlife, especially bird life. Flickr/Parks Victoria

Those numbers do not however include the insects and other invertebrates, which are legion. Being on the water at night during a wet year is a recipe for an invasion of insects and spiders that fall or jump into your boat looking for some place dry to build a web.

Those numbers also do not include the invasive weeds and animals, which, with the exception of cattle, are becoming more abundant every year. Wild horses are a problem, carp are common in the waterways, and foxes prey on the turtles which are culturally significant to the local Aboriginal community.

Humans

Human habitation of the area goes back 40,000 years. The abundance of wildlife and resources meant that indigenous people in the area did not have to be nomadic, but could stay in one place all year.

As early as 1860, the Yorta Yorta nation sought compensation from the government for the destruction of fishing areas by paddle steamers. They sought native title of the Barmah forest in 1984 and continue to have a strong connection to the land. Many members of the community actively contribute to environmental management of the area by helping control weeds by burning off and by supporting research on local turtle species.

European settlement in the mid 1800s was driven by excellent grazing, abundant Red gum timber, and easy transport of wool and wood using the river. Vast numbers of Red gum trees were harvested to supply railway sleepers for new railroads in the 1860s, and other industries thrived, such as beekeeping and leech collecting.

Threats to a thriving ecosystem

Best known as the largest River Red gum forest in the world, the Barmah-Millewa forest has some stands that are over 400 years old, providing important environmental support for breeding birds and other fauna through tree hollows and fallen timber.

Barmah’s natural environment and biodiversity are under threats both man-made and natural. Flickr/Parks Victoria

Each ecosystem within the Barmah-Millewa forest is maintained by the frequency and depth of flooding. Red gums prefer more frequent flooding than Black box, while Moira grass plains prefer shallow annual floods. Sand hills remain dry most years.

Changes to the natural flood regime created by river regulation has affected the health of many ecosystems within the park. The Moira grass plains are suffering the most because they require more regular flooding. The most recent drought has led to the incursion of the grass plains by Giant rush and Red gum saplings. Both are native species, but are growing outside of their natural habitats. Red gums are starting to grow in dry creek beds, threatening to fundamentally alter the environment. This is an area that will benefit from the careful application of environmental water.

Water flows through the area are controlled by regulators and structures, such as canals and earthworks, that were initially designed to prevent the loss of water to the swamp. More recently, environmental water has been used to prolong and extend natural floods. Longer floods support the breeding of water birds such as Little egrets, White ibis, and Royal spoonbills.

Unfortunately, some floods in the area have turned into blackwater events. This occurs when a large amount of leaf litter accumulates over several years and is then inundated. The sudden decay of so much organic matter removes oxygen from the water. The water becomes dark and inhospitable to local fauna: fish die and crayfish crawl out to breathe. Managing these events requires careful planning to recreate a more natural flood regime.

Barmah is reliant on regular flooding to maintain its delicate ecosystem, but this can also bring issues of its own. River Red Gum from Shutterstock

Recent surveys in the Barmah-Millewa wetlands have detected significant and worrying declines in the abundance of birds, fish and some vegetation types. The fish community is only 10% of pre-European levels, and carp, which are an invasive species, are now common. Bird breeding can only occur if floods remain for several months, a situation that is not normally supported by the flood regimes dictated by irrigation schedules.

Fortunately, there are many projects underway to preserve this area, and as an icon site in The Living Murray Program, the Barmah forest will receive hundreds of Gigalitres of environmental water. Some people may think this is wasted water, but this is a wetland that is intricately woven into the web of life that supports all who depend on the Murray River: animals and plants as well as humans.

Next: Riversleigh. Read all the unknown wonders here.

Map of Barmah GoogleMaps

Much of this article was based on the excellent talk by Keith Ward, wetland manager with the Goulburn Broken Catchment Management Authority. Listen to it here.

Join the conversation

14 Comments sorted by

  1. Mick Mac Andrew

    Rev Father

    Susan, your summary of the health and wellbeing of the Barmah-Millewa forest is just what is needed to stimulate a new and innovative investigation into how we both protect and assist such areas to not only survive but to flourish. Your human intervention has raised both our awareness and resolve. Other forms of human intervention should not therefore be ruled taboo in progressing this task. In many areas of the world, human intervention in the form of flourishing - but well managed according to all areas of the science of protection and management, flourishing eco-industries are an essential part of the health and wellbeing of protected forests. The resolve to bring all areas of the science to the table is far overdue in our country and a great denial is in play which surely prevents us taking advantage of what is proving beneficial to forests and communities in many parts of the world.

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    1. Murray Webster

      Forestry-Ecology Consultant/Contractor

      In reply to Mick Mac Andrew

      I agree with you comments Mick. It appears to me that we urban westerners default to a belief in 'the balance of nature' paradigm, i.e. that biodiversity will automatically optimise in the absence of human intervention. However my experience is that this is seldom the case. These forests have been managed by humans for 10's of thousands of years and have replaced eg megafauna as agents of ecological influence.
      I note this tender released by the NSW Govt. It does meet the definition of "logging…

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  2. John Lamp

    Senior Lecturer, School of Information Systems at Deakin University

    I camped in the Barmah-Millewa forest back in 2001. It remains one of my better memories, despite mating koalas waking me! The area should be managed sensitively, as it is quite different to other areas of the Murray that I have visited. Retaining diversity is important. Human activities should be minimal and low impact. "Flourishing eco-industries" are the exception, rather than the rule, around the world. The nature and impact of such activities cannot be determined until the area is better understood. What is "beneficial" is a value judgement which usually depends on whether you are talking about short or long terms consequences.

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  3. Greg North

    Retired Engineer

    Be it the view that environmental water is wasted or not, what cannot be escaped is that just as David Attenborough would tell us the Galapagos Islands are continually evolving, so will Australia and our evolution will take many forms because of human and climatic impacts and ultimately the course taken by the global climate.

    There is no getting away from what a burgeoning global and Australian population will mean in regard to more water being needed for more food and even though Bob Katter on…

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  4. Adrian Gibbs

    Retired

    A lovely explanatory article about a wonderful place to be treasured. I camped there three decades ago, a member of Ian Marshall's team from the Australian National University collecting mosquitoes and the viruses they carried.

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  5. Murray Webster

    Forestry-Ecology Consultant/Contractor

    Just one query on this:
    "About 20,000 years ago, a geological event lifted a large area of land, blocking the Murray River"
    I am not an expert on this but 20 000 seems not long enough, maybe 2 million +(?)
    this from wikipedia:
    "The Murray River became dammed by uplift of over 250 metres (820 ft) in the Grampians in Victoria during the Pleistocene about 2.5 Mya."
    http://en.wikipedia.org/wiki/Murray_Basin

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  6. Kathy Daley

    Water Policy officer

    Thank you Susan for raising the profile of the Barmah-Millewa Forest, which is a great example of the versatility and adaptibility of the Australian landscape. Unfortunatley your article does not recognise the history of recognition of the significance of this area. You recognise that river regulation changed the natural flood regime, you state the regulators were put in place to prevent water loss to the swamps. While this is true, the reason for it was to allow the Forest to have a drying phase…

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    1. Susan Lawler

      Head of Department, Department of Environmental Management & Ecology at La Trobe University

      In reply to Kathy Daley

      My brief was to summarise the natural features of the area, but you are right that the local community is proud of their forest and many of them are actively working to find better ways to manage and protect it. Thanks for sharing the details.

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  7. Peter Farrell

    teaching-principal at at a small rural school

    This lovely place is just a short drive from where I live and I have launched my camp cruiser (8hp) from Barmah on a number of occasions. We have been downstream and that's OK but upstream, where this article is situated, is amazing. After just a few bends in the river you could be miles from any where. Its a special place and thank you for reminding me about 'my own backyard'.

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    1. Tim Connors

      System Administrator

      In reply to Peter Farrell

      I wish I had easy access to the Murray still, after having spent a few years of my childhood a few metres from various levy banks in the Sunraysia district. I rode my motorbike a little bit through Hattah Kulkyne National Park last year, but since it was merely but a waypoint towards my Flinders Ranges trip last year (hell of a detour from Melbourne though), I couldn't spend much time.

      I'd love to do a Tim Flannery & John Doyle (Roy Slaven) style tinnie trip down the Murray. You can tow a "trailer" behind a tinnie and put a motorbike on it, can't you? :)

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