Spatial conservation planning is all about figuring out how to prioritise where you will invest your limited resources so you get the best return on your investment. It's about weighing up the costs and the benefits of investing those resources in different ways. A new analysis by Megan Evans from the Australian National University and colleagues from The University of Queensland and the University of Western Australia has revealed that the manner in which the conservation benefit is calculated is critical to estimating the conservation outcomes that will be generated.
The CEED researchers used a comprehensive decision theoretic approach to identify management priorities for the Great Western Woodlands, a region of high ecological, cultural and economic significance in south-western Australia.
"The Great Western Woodlands is a biodiversity hotspot," says Evans. "It's the world's largest remaining Mediterranean woodland, and supports a globally significant diversity of flora and fauna. The area is under threat from too frequent fires, agricultural expansion, mining activities, as well as introduced herbivores, carnivores and weeds. As a result, some areas are more degraded than others."
The researchers identified priority areas for investment that would best maintain the native vegetation of the Woodlands in its current condition or restore natural fire regimes.
"But rather than assume that the landscape is homogenous in terms of condition, we used information on the condition of all sites across the Woodlands to calculate the expected benefit of applying particular actions, combined with the cost of those actions" says Evans.
They then compared these results to spatial priorities identified using two alternative approaches that are commonly used in conservation planning. First they ignored landscape condition, so priorities were identified only using information on management costs. Second they assumed that landscape condition is a surrogate for the cost of management, with poor condition areas assumed to have higher costs.
"What we found was that far better outcomes were delivered using our comprehensive approach than the alternatives, since we were able to simultaneously account for landscape condition and management costs when identifying conservation priorities. Using landscape condition as a surrogate for management costs would reduce the cost-effectiveness of management."
The researchers argue that the conservation benefit of a management action must be considered relative to what would have happened in the absence of management. Conservation planning analyses that ignore landscape condition or fail to account for management costs run the risk of misspending conservation funding on areas that aren't the highest priority for investment.
Megan C. Evans, Ayesha I.T. Tulloch, Elizabeth A. Law, Keren G. Raiter, Hugh P. Possingham, Kerrie A. Wilson, Clear consideration of costs, condition and conservation benefits yields better planning outcomes, Biological Conservation, Volume 191, November 2015, Pages 716-727, ISSN 0006-3207, http://dx.doi.org/10.1016/j.biocon.2015.08.023 .