A transformed and contested land
The biodiversity of the Brigalow Belt is of national and global significance. This bioregion supports more bird species than any other bioregion in Australia, including the rare glossy black-cockatoo and the red goshawk. It is home to reptiles that occur nowhere else in the world, such as the golden-tailed gecko and the brigalow scaly-foot, and holds some of the last remaining wild populations of iconic Australian mammals: the bridled nailtail wallaby and the northern hairy-nosed wombat.
The ecological values of Queensland's Brigalow Belt are under threat due to a myriad of anthropogenic activities. Land clearing and agricultural expansion since the mid 1800s make it one of Australia's most ecologically transformed areas. Further threats include invasive plants and animals, pollution, changed fire, grazing and hydrological regimes, and climate change. On top of this, the expansion of coal mining as well as the coal seam gas industry introduces more pressure on native species populations in the region.
Within the Brigalow Belt, eight species are extinct and a total of 147 species and 100 ecological communities are listed as threatened. The once dominant brigalow forest, giving the region its name, only covers 5 per cent of its original land area.
Targeting limited resources for the best chance of success
Many land managers in the Brigalow Belt region are working to conserve and protect the significant ecological values of the region and would benefit from a region-wide assessment of threat management options to target limited resources.
This project applied a priority threat management approach, as has been used successfully in the Kimberley, Pilbara and Lake Eyre Basin, to determine the best strategies for protecting the imperilled species of the Brigalow Belt bioregion. This involved a consultation process with 40 experts and stakeholders in biodiversity and land management of the region, and the best available scientific data and expert knowledge.
The stakeholder group identified 179 species (102 plants and 77 animals) as 'imperilled' based on state and federal legislation and expert knowledge of the likelihood of significant declines over the next 50 years.
The group then identified and prioritised management strategies by their ecological cost-effectiveness, and assessed which combinations of strategies offer the best investment options under limited budgets and provide flexible, rational and repeatable guidance for making management decisions.
Costed and prioritised threat management strategies
Using the priority threat management approach, the stakeholder group identified 11 strategies that target several threats to Brigalow Belt biodiversity:
- protect remnant vegetation
- protect important regrowth vegetation
- establish key biodiversity areas, such as identify and manage areas of critical habitat
- restore key habitats
- manage pest animals such as feral cats, pigs and noisy miners
- manage invasive plants
- manage fire
- manage grazing
- manage water
- manage pollution
- build a common vision.
The stakeholder group saw "build a common vision" as vital to achieving the other strategies and assessment showed that it would improve the effectiveness of the other management strategies.
The most cost-effective strategies for improving the overall persistence of imperilled species in the region are the management of fire regimes and invasive plants, at an average annual cost of A$0.55 m and A$1.53 m respectively. These strategies were ranked first and second for improving the persistence of native plants, animals and all 179 native species combined.
The assessment estimated that it would cost about A$57.5 million each year to implement all 11 proposed management strategies in the Brigalow Belt, which is around A$1.60 per hectare each year.
Implementing the 11 strategies would likely save 12 of 21 species that are predicted to disappear from the Brigalow Belt over the next 50 years, and the outlook of many other species would improve. Species-specific recovery plans may help stop the other nine species (such as the northern-hairy nosed wombat and the swift parrot) from being lost from the region.
This report was funded by the Gas Industry Social and Environmental Research Alliance (GISERA).