Indirect effects of invasive species removal devastate World Heritage Island

Owing to the detrimental impacts of invasive alien species, their control is often a priority for conservation management. Whereas the potential for unforeseen consequences of management is recognized, their associated complexity and costs are less widely appreciated.
We demonstrate that theoretically plausible trophic cascades associated with invasive species removal not only take place in reality, but can also result in rapid and drastic landscape-wide changes to ecosystems.
Using a combination of population data from of an invasive herbivore, plot-scale vegetation analyses, and satellite imagery, we show how a management intervention to eradicate a mesopredator has inadvertently and rapidly precipitated landscape-wide change on sub-Antarctic Macquarie Island. This happened despite the eradication being positioned within an integrated pest management framework. Following eradication of cats Felis catus in 2001, rabbit Oryctolagus cuniculus numbers increased substantially although a control action was in place (Myxoma virus), resulting in island-wide ecosystem effects.
Synthesis and applications. Our results highlight an important lesson for conservation agencies working to eradicate invasive species globally; that is, risk assessment of management interventions must explicitly consider and plan for their indirect effects, or face substantial subsequent costs. On Macquarie Island, the cost of further conservation action will exceed AU$24 million.

Author Dana M. Bergstrom, Arko Lucieer, Kate Kiefer, Jane Wasley, Lee Belbin, Tore K. Pedersen, Steven L. Chown
Date 14/01/2009
Year 2009
Secondary title Journal of Applied Ecology
Volume 46
Number 1
Institution Australian Antarctic Division, Department of the
Department Australian Antarctic Division, Department of the
Pages 73-81
Notes Notes
ISBN/ISSN DOI: 10.1111/j.1365-2664.2008.01601.x
Region TAS
Links https://dx.doi.org/10.1111/j.1365-2664.2008.01601.x