Posts Tagged ‘Australia’

Focus on the process! That’s what restoring ecosystems means, and needs.

Friday, August 31st, 2012

In 2011, Australian ecologists David J. Tongway and John A. Ludwig, published a grand summary of their multiple years of on-the-ground experience of restoring disturbed landscapes and ecosystems. Using examples from restoration works on mine sites, road verges, rangelands, and farmland they illustrate how their function-based approach plays out.

The book, “restoring disturbed landscapes – putting principles into practice“, published by Island Press, is a very accessible introduction to the Ecosystem Function Analysis method developed by CSIRO.

One of their main ideas is that restoring degraded ecosystems first requires that the problematic physical (abiotic) processes be solved: the negative effects of topography on water and material flows must be mitigated before self-sustaining biological processes can play their part (e.g. vegetation, grazing regimes, etc.).

First, solve the underlying physical processes! No point in planting your favourite flower here…

Of course, they also remind us that restoration must be framed and carried out in an adaptive management feedback loop where the ecosystem or landscape’s trajectory is monitored and compared to reference conditions. The book is a nicely illustrated reminder of these good practices…

In the context of mitigation requirements for development impacts on biodiversity, the following quote summarizes nicely one of their main points:

switching from simply observing the presence, absence, or abundance of organisms to assessing the status of functional processes in an explicitly spatial (landscape) context is as challenging as venturing into previously uncharted waters. (…) Being able to “read the landscape” is a rare and valuable asset.

On time-lags and location selection in offsets

Monday, October 10th, 2011

Ascelin Gordon and his colleagues from Melbourne recently went through an interesting modelling exercise. They modelled the long-term effects, in both space and time, of different offset policies concerning urban development impacts on native grasslands around the city.

Their modelling explicitly included uncertainties , following the approach described by Langford et al. (2009). These uncertainties were both ecological (edge effects on conservation value, grassland response to management and offsetting, etc.) and political: which offset policy?

They compared five different offset policies:

  • No change
  • Development without offsets
  • Non strategic offsets (wherever, whenever)
  • Strategic offsets (offsets are located together, in designated areas)
  • Strategic immediate offsets (offsets are effective at the start of simulations, a.k.a. habitat banking)
  • Their conclusions are that offset policies that include spatial and temporal constraints on offsets give the best conservation outcomes. They also point out the obvious: the selection of the baseline is central to any assessment of policy outcomes.

    whether (or when) [policies] achieve the objective of a “net gain” completely depends on the choice of baseline.

    It might be obvious but it is certainly tricky when looking at policies that involve long-term ecological dynamics…

    To find out more, check out their paper in Environmental Modelling & Software*. A pdf can be downloaded here.

    * Gordon A., Langford W.T., Todd J.A., White M.D., Mullerworth D.W. & Bekessy S.A. (in press): Assessing the impacts of biodiversity offset policies. Environmental Modelling & Software, in press.

    Has Australian biobanking lost all credibility?

    Friday, February 18th, 2011

    Biobanking was launched in the Australian state of New South Wales (NSW) in 2009* in order to streamline the requirement for developers to avoid, reduce and offset their impacts on biodiversity.

    Biobanking is inspired by similar policy instruments in the USA and elsewhere whereby developers can purchase “credits” sold by “banks” who have created “biodiversity gains” in advance of future impacts. As such, banking schemes solve some of the difficulties of offsetting impacts : taking into account delays between impact losses and offset gains and the uncertainties of actually obtaining these gains.

    On the downside, conservationists often argue that such “banks” give the false impression that all impacts can be offset, thereby giving an incentive to downplay or ignore the requirement to first avoid and reduce impacts.

    A major development operation in the Hunter valley of NSW resorted to biobanking to offset its impacts but it was revealed that errors where made in sizing the required offset actions. This is a serious blow to the credibility of biobanking as an instrument for mitigating development impacts on biodiversity. An article in the Sydney Morning Herald tells us that:

    The 644.4 hectares of clearing requires 37,010 credits, while the 887.0 hectares of biobank site generates 9607 credits. This results in a shortfall of 27,403 credits. The results show that between 2614.5 to 4107 hectares of additional offset is required to satisfy the offset required by the biobanking assessment.

    It will be interesting to see how this particular mishap will play out on the development of biobanking in NSW but also in its spread to other Australian states.

    * The scheme was set up through the Threatened Species Conservation Amendment (Biodiversity Banking) Act of 2006.