Bush Heritage Newsletter

	Bush Heritage News	Spring 2007

Northern quoll. PHOTO: JIRI LOCHMAN/LOCHMAN TRANSPARENCIES

An iconic property in far-north Queensland

Ecologist David Baker-Gabb and Bush Heritage’s Mel Sheppard were part of the initial team that assessed the property Yourka Station for potential acquisition by Bush Heritage

The thought of heading north in May to assess a 43 500 hectare property for possible acquisition by Bush Heritage had particular appeal. After living for months in the drought-ravaged brown landscape of southern Australia, far-north Queensland was guaranteed to be green and wet. But just how green and wet we were yet to find out!

Our trip to Yourka Station was delayed because of the wet. At that time the soaked ground would not allow us access to most of the property, even by quad bike. When we finally arrived and gazed up at the flood debris lodged 20 metres above the ground in the branches of the trees, we appreciated just how much water must have surged through this extraordinary landscape. Much of the rain had fallen in the high-altitude tropical rainforests of the Wet Tropics World Heritage Area along the property’s eastern boundary.

It had then rushed through the foothills down a series of major creeks and across the plains to join the swollen Herbert River on Yourka’s western boundary. The result was a lush, green and exuberant landscape.

We had not expected to be so captivated by the diversity of Yourka’s waterways. They ranged from the dark, wide Cameron Creek, which meandered through the south of the property, to the rushing milky blue waters of rocky Blunder Creek, which tumbled past pandanus and through eucalypt woodlands in the north. In between were the deep, sparkling waters and white sands of Sunday Creek with its fringing billabongs and ephemeral wetlands. As its name suggests, the underlying rock and character of Basalt Creek on Yourka’s rich alluvial plains were different again. We were to learn that the diversity of these seasonal wetlands and waterways was amplified in Yourka’s vegetation communities.

From early on in our assessment we had the strong impression that Yourka Station could become one of Bush Heritage’s iconic properties. The more we explored, the more excited we became by the thought that Bush Heritage and its supporters might be able to protect this stunning piece of country within the year. Located in one of Australia’s biodiversity hotspots, and in a Bush Heritage anchor region, it would be a significant addition to the national reserve system.

There are things about Yourka that make it truly special and a very significant property to protect.

Firstly, it is highly diverse. Within its boundaries are 39 regional ecosystems. Five of these have very little protection in any other reserve and fourteen are listed as threatened or ‘of concern’.

This remarkable level of diversity is due to the variability of the underlying geology and also the changes in altitude and rainfall across the property. As we journeyed from west to east we travelled through a variety of vegetation types. There were eucalypt and Corymbia woodlands, some with understoreys of native grasses and others with shrubby understoreys, impressive stands of grass trees, rocky escarpments and wet eucalypt forests that fringed the rainforest of the Wet Tropics. Along the waterways, giant melaleucas, which towered above our heads, whispering she-oak woodlands and stream-side thickets helped create an impressive diversity of habitats for the local wildlife.

Secondly, Yourka provides habitat for a significant number of threatened species. Its multi-aged woodlands with old, hollow-bearing trees are a key resource for forest and woodland species.

From top: Colourful poison pea Gastrolobium sp. Lowland wetland. Native hibiscus. Milky blue water of blunder creek. PHOTOS: DAVID BAKER-GABB

Mareeba rock wallabies. PHOTO: JIRI LOCHMAN/LOCHMAN TRANSPARENCIES

One of the great delights was finding nests of the red goshawk, our rarest bird of prey. This species is nationally vulnerable and there are probably only about 700 pairs left in Australia. The species’ range has shrunk as coastal developments have pushed it back to the more remote northern rivers.

Another potentially even more exciting discovery was of the telltale scratchings of bettongs. Dr Graeme Harrington, an experienced tropical ecologist who was travelling with us, was optimistic that, considering the habitat in which we found the diggings, they could well be those of the endangered northern bettong. Only four isolated populations of this species are known to remain. Finding a fifth population on Yourka would be very exciting.

Other threatened species that may well be found here include the endangered northern quoll, spot-tailed quoll, Sermon’s leaf-nosed bat and greater large-eared horseshoe bat, and the vulnerable fluffy glider, masked owl and painted snipe. In the rocky country we saw Mareeba rock wallabies hiding in the rock crevices and bouncing like rubber balls up the rock faces.

The property is also significant for threatened plants. Around ten per cent of the property is listed as potential habitat for geographically restricted or threatened plants, including the endangered Phalaenopsis sp. and the vulnerable Acacia purpureopetala and Homoranthus porteri.

The third reason that Yourka is so special relates to its gradients of rainfall and elevation. These increase as you travel from west to east. As we begin to better understand the impacts of global warming and realise that every one degree increase in temperature will be equivalent to a particular habitat being subject to the conditions experienced formerly 100 kilometres to its north, we can see that it is important to protect land that extends through a range of altitudes. As changes in the patterns of rainfall and temperature occur as the climate warms, habitats will be altered as a result. They may no longer support the species that depended on them in the past. By protecting extensive areas of land with differences in elevation, we can provide displaced animals and plants with more suitable habitats to move into.

At present Yourka faces a number of threats. Grazing pressure from stock is the most severe and is having the greatest impact, particularly as the best grazing land is also where most of the threatened ecosystems occur. Weeds, especially lantana, are also an issue in the grazing areas. Pigs are damaging the wetlands. Fire has been suppressed and as a result the wet eucalypt forests are being invaded by rainforest species. The birds and animals that are unique to these forests are therefore under threat.

If you can help Bush Heritage to secure Yourka, the greatest threat will be removed. The cattle will go. Management of pigs, weeds and fire will follow, as permanent reserve managers, supported by volunteers, take over the land management. Traditional Owners will be invited to contribute to the reserve’s management and the protection of Yourka’s cultural heritage. The property will then begin its transition to becoming the iconic reserve it deserves to be.

Following our assessment of Yourka Station, the Bush Heritage Board approved its purchase. The Australian Government has committed significant funds for the acquisition from the Maintaining Australia’s Biodiversity Hotspots Programme.

From top: Nationally vulnerable red goshawk. Quad bikes were the best form of transport. PHOTOS: DAVID BAKER-GABB Monochoria cyanea was flowering in some of the wetlands. PHOTO: MEL SHEPPARD Rocky Tiger Mountain. PHOTO: DAVID BAKER-GABB Northern bettong. PHOTO: JIRI LOCHMAN/LOCHMAN TRANSPARENCIES

Mid-altitude grassy woodland. PHOTO: DAVID BAKER-GABB