Biodiversity simply means a diversity of plant and animal life. In most bioregions diversity is wide-ranging; in many it is vulnerable and in need of protection, all the more so following the recent election of climate-change deniers and 'green-tape' cutters to Canberra. In the Land Court in Brisbane last week, the discussion was quite specific: how the development of the Alpha coal mine would impact not only on the landscape that will be destroyed during its creation but also on neighbouring properties that include Bimblebox Nature Reserve.

BNR was created more than a decade ago with the intention of protecting an area of high conservation value, including a remnant desert upland ecosystem. A nature refuge is established under a voluntary agreement between the Queensland government and a landowner, enabling that landowner to maintain a living from sustainable use of the land while conserving its features of value. The Nature Refuges Program outlines clearly that such an agreement is:

perpetual, registrable on title and binds successive owners or lessees of the land. A nature refuge is the best way landholders can ensure the good land management practices and conservation works they have initiated will be continued when future generations or new owners take over.

The Oxford English Dictionary defines perpetual as 'lasting or destined to last for ever; eternal'.

The co-owners of Bimblebox bought the cattle station to save it from being cleared – there was a clearing permit attached to the sale of the property. The Queensland government contributed $300,000 towards the purchase. Between $10,000 and $40,000 a year is required to maintain the environmental management plan – clearing exotic plant species, controlling feral animals, and mitigating bush fires. Cattle help to trample down invasive buffel grass so it won't be fuel for the fires: cows are part of the plan.

Bimblebox includes six vegetation zones, more than 150 different species of birds, an abundance of reptiles and diverse flora. The birds include – sometimes – the Black-throated Finch, which has gained notoriety since mega mines were proposed for the Galilee Basin and landowners and conservation groups drew attention to fauna and flora that are likely to be lost as a result. The Finches used to range from well up in Queensland's Pointy Bit down to northeastern New South Wales. They are more common in the north but the birds' most southerly sighting in recent times was at Rockhampton in 2004, and then 15 were spotted at Bimblebox in May 2011. It is estimated that the Finch's range has contracted by between 53 and 80 per cent.

With extensive clearing of the region, a sizeable area of remaining woodland such as Bimblebox becomes even more valuable as it is ecologically and genetically more resilient than small patches whose connectivity has been lost. This is even more significant when it comes to the efficacy of biodiversity offsetting. The Nature Refuge increases the options of food sources for species during drought conditions, for example. Some species such as the Black-throated Finch are unable to migrate very far without water or food. It is currently classed as endangered, as is the Northern Quoll, a marsupial. 

Bimblebox is home to other at-risk species and ecological communities: threatened (Brigalow); near-threatened (Black-chinned Honeyeater); vulnerable (Squatter Pigeon, right); and regionally significant (Australian Bustard, bottom of page). The Refuge is also the location of important research, for example how the bioregion responds to fire.

In court last week it was revealed that targeted surveys of the Black-throated Finch were not carried out in the preparation of Alpha's EIS even though the Federal government's Significant Impact Guidelines for that particular species were already in place at the time. There were no fauna transects, whereby a species is counted and recorded along a fixed path and then the probability of it being present calculated across a wider area. However, in determining biodiversity values for the Alpha mining lease area, whether or not the Finch was actually spotted was not a reference point for impact assessment; rather it was the potential of that particular habitat for the bird to be present. Habitat modelling identifies certain landscape features with the potential for providing suitable habitat for a species. Hancock's expert witness – an ecology manager from a firm of environmental consultants – thought it unlikely that the Black-throated Finch was in fact present on the Alpha mine site.

The discussion in Court moved on to the likelihood of the regional extinction of a species with the impact of the mine. Again, it was not the actual percentage of suitable habitat that was going to be removed but a theoretical percentage of an area with the potential to house the habitat. Biodiversity and extinction are complex subjects, and the conceptualisation of modelling parameters has already challenged the Court. Extinction is not only about habitat loss or fragmentation but also factors such as the management of weeds and pests and land use practices.

State and Federal approval of a mine on the scale of Alpha comes with conditions attached, including management plans to protect the area's biodiversity values. If a landscape is to be decimated then biodiversity offsetting comes into play. And therein lies another rather convoluted concept.