?Everyone from mining companies to regulatory authorities and restoration ecologists has been working to a ?build it and they will come? paradigm,? said the lead author of the study, Romane Cristescu, a former PhD student in the University of New South Wales School of Biological, Earth and Environmental Sciences.
?In other words, the general belief is that if you provide great quality flora, fauna will recolonise. What we found is that, for koalas at least, in practice that simply isn?t so in most cases.?
In a study published in the Journal of Applied Ecology, Cristescu and colleagues note that the rehabilitation of degraded and disturbed landscapes, notably those used temporarily for mining and quarrying, has become critical for counteracting habitat and biodiversity loss.
But the success of rehabilitation projects has been judged on achieving goals that focus on non-living criteria ? such as landform, stability, erosion and water quality ? or on restoring complex plant communities.
?What we noticed is that these goals usually overlook fauna, with no requirement to include them in rehabilitation monitoring,? said Cristescu. This is true even in closely regulated countries, such as Australia and North America.
The authors decided to test scientifically whether the criteria for a successful restoration of flora translated into success for fauna. The study site was a sand mining operation on North Stradbroke Island, where the Sibelco mining company, endorsed by the Australian Government, became only the second Australian mining company to reach an agreement with all stakeholders about rehabilitation success criteria. Sibelco financed the research project to understand better how fauna respond to rehabilitation.
?So we took a fauna species everyone agrees should really come back to mine rehabilitated areas before we can declare it a success: the koala,? said Cristescu.
?They are vulnerable and charismatic animals, and everyone wants them to benefit from rehabilitation. So our question was simple: if we built a great flora, will koalas come?
?We measured flora quality based on the very goals mining companies and government are using to measure rehabilitation success, then we looked at what koalas themselves judged to be success; that is, which rehabilitated areas they recolonised.?
Koalas buck the trend
It turned out that human goals and koala goals were different. In fact, the most successful areas in terms of flora goals ? with a greater than 70 per cent success rate ? more often than not had no koalas using them. But koalas were using many other rehabilitated areas rated much lower for floral success.
?We proved that mining rehabilitation could be a success for both fauna and flora, but that the two are not necessarily congruent,? Cristescu explained. ?We need goals to measure whether we are succeeding in rebuilding a functioning ecosystem, and many ecosystem functions actually rely on fauna for services such as pollination and nutrient cycling.
?We hope our work will influence the mining industry and its legislators to include fauna in their rehabilitation success goals. Only then can we ensure a positive impact of mine rehabilitation on all parts of biodiversity.?
Although the study was not able to determine what factors influenced the return of the koalas, Cristescu said we “cannot underestimate the influence on species recolonisation of factors such as interactions with other species, social structure and behaviour or dispersal abilities”.
While the study only examined koalas, it was concluded other animals would be similarly affected, though “obviously what influences a koala and a lizard would be totally different”, she said.
Cristescu has now been employed by Sibelco to look at recolonisation by other animal species and to determine what factors encourage the return of animal life.
Sources: Industry Search, Journal of Applied Ecology, ABC Science, Science Alert, The University of New South Wales