What to do in the face of multiple threats? Incorporating dependencies within a return on investment framework for conservation. Diversity and Distributions 17:437-450. doi.10.1111/j.1472-4642.2011.00747.x
Aim Our study aimed to determine priority areas for conservation investment with explicit consideration of the impacts of multiple threatening processes, and the dependencies that exist between actions required to abate these threats.
Methods We analysed the return on investment for two different management actions aimed at reducing the impact of invasive species on the native fauna and flora of Australia. We focussed on the management of the European red fox (Vulpes vulpes) and European rabbit (Oryctolagus cuniculus) at two spatial scales: across 72 biogeographic regions of Australia and within one high-priority biogeographic region. We considered each action independently and also explicitly accounted for the option of an integrated fox and rabbit management action. We accounted for the spatial distributions of the threatened species within our analysis and determined how this refined spatial information influenced both the priority areas and the timing of this investment.
Results Integrated fox and rabbit management was identified as a higher priority th
an singular threat abatement in most bioregions, whereas rabbit control alone was the most frequent priority if dependencies between actions were ignored. At the regional scale, funding was entirely directed to integrated action when seven or more species within the priority region were impacted by more than one threat. The total allocation of funding and timing of initial investment remained relatively insensitive to differences in the spatial overlap of species distributions.
Main conclusions Our findings indicate that prioritizing conservation actions without explicit consideration of the impacts of multiple threats can reduce the cost-effectiveness of investments. The benefits expected from investment in abating one threat alone may be overestimated where other processes continue to threaten species persistence. We conclude that future attention should be directed to refining our understanding of the cost-efficiencies delivered through integrated actions and institutional mechanisms to achieve their delivery.
Figure 2. Investment into conservation actions at a continental scale for all 72 bioregions, according to our four ROI frameworks: (a) Two-action-independent ROI, (b) three-action-independent ROI, (c) action-dependent ROI and (d) action-dependent ROI with spatial targeting. The map shows the priority bioregions for investment as indicated by the total percentage of funding for a bioregion summed over all actions, which is shown as low (up to 1%), medium (up to 2%) or high (up to 6%).