Brigalow Gone to Pasture
Brigalow (Acacia harpophylla) is a species of silvery wattle that gives the mosaic of open forest and woodland communities known as the Brigalow Belt its name. The canopy is usually 10-15m in height, and the dominant tree species that may occur with Brigalow include Belah, Gidgee, Lancewood or Bendee.
Along the eastern boundary of the Brigalow Belt are scattered patches of semi-evergreen vine thickets with bright green leaves that are highly visible among the more silvery brigalow communities. These patches are related to rainforests and are remnants of the extensive subtropical rainforest vegetation that occupied much of the brigalow lands millions of years ago.
The Brigalow Belt ecosystems provide habitat for a distinctive fauna. Unfortunately, many of the species that presently or formerly occurred in Brigalow communities are now nationally threatened, including the Bridled Nailtail Wallaby (E), Northern Hairy-nosed Wombat (E), Black-breasted Button-quail (V), Squatter Pigeon (V), Brigalow Scaly-foot (V), Ornamental Snake (V) and the Black-throated Finch (V). A number of brigalow reptiles will probably soon join that list.
The Brigalow Belt spans inland and eastern Queensland from Townsville in the north to northern New South Wales, covering an area of about six million ha. Despite such a large area, only about two per cent of the Brigalow Belt is protected in conservation reserves. There is strong concern that communities on prime agricultural lands which have been extensively cleared are especially under-represented in reserves.
Within Queensland, the Brigalow Belt has been divided into 163 different regional ecosystems. Semi-evergreen vine thickets occur in only 10 of these. Four of the vine thicket ecosystems are considered endangered (less than 15 per cent remaining) and three considered of concern (less than 30 per cent remaining), although none is as yet listed as such under national legislation. One further vine thicket ecosystem in northern NSW has been formally listed as Endangered under the Environment Protection and Biodiversity Conservation Act 1999, the national threatened species legislation.
The major threat to the original Brigalow Belt communities, since European settlement, has been clearing or severe modification of the vegetation because much of the landscape is so eminently suitable for agriculture. Most of the clearing has occurred since 1960 and is still continuing.
Of the animal species that formerly occupied the Brigalow Belt, several are now totally extinct, including the Paradise Parrot, White-footed Rabbit-rat, Brush-tailed Bettong and the Darling Downs Hopping-mouse. A number of other animal species are now regionally extinct, for example the Bilby, Eastern Quoll and Long-nosed Bandicoot. The same situation also applies to native flora. Many of the Brigalow remnants on which native species now depend are marginal habitats such as steep, rocky slopes or are in poor condition and highly degraded. Tree and shrub cover are much reduced, there is a high incidence of weeds and feral animals which either further ruin the landscape (digging by rabbits, for example) or prey upon native animals. Over-grazing, soil erosion, raised water tables and salinity further reduce the quality of the remaining habitats.
Recovery plans are being developed and implemented for the nationally threatened species in the Brigalow Belt to identify what actions are needed to help the species back to a secure and stable status. Ecological communities can also be listed under the Commonwealth Environment Protection and Biodiversity Conservation Act and a number of Brigalow communities have been nominated for Commonwealth listing. If listed they will have recovery plans developed and implemented. It is vital to ensure that significant and large remnants are included in conservation reserves before they, too, are seriously fragmented.
Conservation of Brigalow and its dependent species depends on an approach that involves the whole community and integrates nature conservation into land management. If you have a Brigalow remnant on your property, consider how you can best protect it and maybe enter into a conservation agreement. If you live near a Brigalow remnant, you could get involved with an organisation that is helping to protect it or any of its dependent threatened species.
You also can help by:
- protecting remnant bush in your community or on your land to help provide habitat for all our native species.
- supporting local efforts to conserve threatened species in your area by joining a local organisation such as a Landcare or catchment group, natural history or a 'friends of' group or by volunteering for Green Corps or the Australian Trust for Conservation Volunteers;
- participating in special events, information nights, tree planting days and weed eradication programs.
To find out more about saving your state's threatened species check out the Threatened Species Network web site at http://www.wwf.org.au/tsn/index.htm or call the Network's National Office on (02) 9281 5515.
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
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