Open Cut » Environment
For an increasing number of open cut coal mines in central Queensland, overall rehabilitation objectives include the re-establishment of self-sustaining ecosystems that reflect biodiversity values of the land prior to mining. Vertebrate fauna is a key component of such biodiversity values, and fauna colonisation provides important opportunities to measure the success of rehabilitation development.
There are concerns that for many vertebrate fauna species, the development of suitable habitat conditions within post-mining rehabilitation may take many years to decades, e.g. tree hollows. Such timeframes usually do not accord with mining lease relinquishment. For some fauna species and faunal groups, the introduction of certain habitat resources offers the potential to accelerate fauna colonisation within otherwise unsuitable areas of rehabilitation. These physical habitat enhancements have been used as either retrofits to existing rehabilitation, or incorporated in the initial development of new rehabilitation.
Agnew et. al. (2003) analysed results from a series of vertebrate fauna surveys conducted on a wide range of Bowen Basin mine sites. That research concluded that one of the primary factors influencing differences in fauna diversity results between rehabilitation and natural environments related to microhabitat (niche) diversity. Particular attention was focussed on niches provided by resources, such as tree hollows and ground logs, and the implications for fauna colonisation of rehabilitation that lacked such resources.
That research identified that microchiropteran bats contributed to a significant proportion of the mammal fauna recorded from Bowen Basin mines, and that suitable microbat roost habitat was rare within mine rehabilitation. This suggests that the current value of these post-mining environments for microbats is primarily limited to the provision of foraging habitat, with animals travelling to and from suitable roosting habitats off-site.
Many microbat species, which were recorded within mine rehabilitation habitats, demonstrate an adaptability to use artificial structures provided they approximate structural and microclimatic conditions of natural sites. At present, there are no examples of sites in the Bowen Basin where habitat enhancement structures, specifically for microbats, have been deployed within rehabilitation. Elsewhere in Queensland and Australia, a variety of habitat enhancement structures have been trialled with varying degrees of success within rehabilitation, forest regrowth and agriforestery.
The primary objective of this project was to investigate applicability of a structure that can enhance microbat fauna habitat values and increase rates of colonisation within mine rehabilitation of the Bowen Basin