Maggini, R, Kujala, H, Taylor, MFJ, Lee, JR, Possingham, HP, Wintle, BA & Fuller, RA. 2013. Protecting and restoring habitat to help Australia’s threatened species adapt to climate change. National Climate Change Adaptation Research Facility, Gold Coast.
1. SUMMARY FOR POLICYMAKERS
Australia’s biodiversity is threatened by climate change, but we currently know little about the scale of the threat or how to deploy on ground conservation actions to protect biodiversity against the changes expected. In this project we predict the impacts of climate change for threatened species and delineate the best options for climate adaptation for all these species collectively via protecting and restoring their habitat.
For 504 of Australia’s currently threatened species we predict their distributional responses to climate change, under three climate change scenarios of increasing severity: early mitigation, delayed mitigation and business-as-usual. We then simulate the optimal placement of new protected areas and where necessary, restoration of critical habitat for those species most affected by a changing climate, taking into account variation in the costs and benefits of taking action in different places.
We measured the benefits of protecting and restoring habitat by considering the long-term availability and quality of habitat for threatened species as climate changes. We undertook a state-of-the-art multi-action optimisation that accounts for spatial and temporal habitat connectivity under climate change. The scale of the prioritisation analysis implemented here is unprecedented in the conservation literature, and is only possible because of recent advances in software sophistication and parallel computer processing power.
We discovered that:
– Fifty-nine of the 355 threatened plant species and 11 of the 149 threatened animals considered could completely lose their climatically suitable range by 2085 under the most pessimistic (business as usual) climate change scenario, while four plant species face almost certain extinction due to complete loss of suitable range even under the most optimistic mitigation scenario tested.
– Climate is predicted to become unsuitable across more than half of their geographic distribution for 310 (61%) of the modelled species under the business-as-usual scenario and for 80 (16%) species under the early mitigation scenario.
– For an available budget of $3 billion, protecting an additional 877,415 km2 of intact habitat, and restoring 1,190 km2 of degraded habitat immediately was identified by our analysis as the optimal set of actions to help the 504 threatened species adapt to climate change assuming early mitigation. Under a more pessimistic business-as-usual climate change scenario, 837,914 km2 of protection is required, along with 77 km2 of restoration. In all cases, appropriate threat management within the protected areas is required.
– Within the $3 billion budget, optimal allocation of protection focuses on forests and woodland areas of eastern Australia, Northern Territory, the Great Western Woodlands of Western Australia, and southern South Australia. Restoration effort is required mostly in south-eastern Australia.
– We tested a range of conservation budgets from $500 million to $8 billion, and found that the spatial pattern of priority does not change dramatically, and that conservation gains do not level off within that range, i.e. that each dollar invested up to at least $8 billion generates additional benefits for threatened species under climate change.
Our analysis deals only with threatened species, i.e. those currently most vulnerable to threats including climate change, and while this doesn’t represent all Australian native animals and plants and how they may all be best provided for, these species have great immediate significance for national biodiversity policy.
In sum, the 504 threatened species considered in this study require an increase of between 838,077 km2 and 878,590 km2 in areas protected against loss or degradation either through legislation to protect habitat, designation of protected areas, or negotiations of long-lasting voluntary conservation covenants.