It’s true: many species will go extinct due to the direct and indirect impacts of climate change.
We will have to make some hard decisions about where to invest conservation dollars for the best effect. So, how do we minimise the number of species we will lose?
Extinctions are on the up and climate change will make it worse
Climate change will exacerbate the many existing threats to species, including habitat loss, over exploitation and invasive species.
This is not news to ecologists. Dire predictions about climate change’s impacts on species and ecosystems are easy to find in the scientific literature and the popular media.
But what are we going to do about it?
We have limited control over global warming, we have little money with which to protect species and we have many possible courses of action, only a portion of which can we afford to try.
From the perspective of conservation scientists and practitioners, the question is how best to invest limited conservation and climate adaptation resources to minimise the number of species going extinct.
This is the question we set out to tackle in a recent climate adaptation research project funded by Australia’s National Environment Research Program and the ARC Centre of Excellence for Environmental Decisions.
Getting the best bang for your conservation buck
We approached this question using a combination of ecological and economic models that help us to:
1) predict the probability that a species will go extinct under a set of climate change scenarios
2) predict how much extinction risk can be reduced by implementing particular conservation actions
3) estimate the cost of implementing those actions
4) figure out the most cost-effective portfolio of conservation actions for a given budget, based on the above estimates of extinction risk reduction and cost.
In short, we figure out how to provide the “best bang for our conservation buck”.
While this sounds fairly logical, the primary challenge is coming up with the best possible estimates of conservation benefit (reduced extinction risk across multiple species), and management costs.
There are a number of factors that make this a significant challenge:
global warming scenarios are inherently uncertain
we don’t know exactly how global change will influence local weather patterns
we have a relatively poor understanding of ecological processes that mediate particular species extinction risk
the number of species at risk is huge
we don’t know enough about the effectiveness of management
Applying this approach in South Africa
Our first attempt at an ecological-economic model was published on September 18 in the journal Nature Climate Change. We showed how our approach can be applied to make conservation investment decisions to conserve species in the South African Fynbos Biome – a global biodiversity hotspot of phenomenal beauty.
The fynbos ecosystem supports more than 6,200 endemic plant species in an area less than the size of Tasmania. Many of those species are highly threatened by the direct and indirect impacts of climate change and the increased frequency and intensity of fires.
These threats compound the already severe impacts of habitat loss (land clearing) and weed invasion.
In collaboration with Brian van Wilgen from CSIR South Africa, we developed mathematical models to predict the risk of extinction (by 2050) for a set of fynbos Proteas and Leucadendrons (both flowering shrubs). We considered these extinction risks under a range of fire management, weed management and habitat protection investment scenarios and using the IPCC’s A1FI climate change projection.
Using these models, we identified the most cost-effective portfolio of conservation investment for reducing extinction risk of fynbos species.
So, what did we find?
Well, under a no-extra-investment scenario, with current habitat loss rates and climate change, the average risk of extinction by 2050 was more than 90% for many species.
We found that if conservation budgets were increased by around US$60 million per year, mostly allocated to early-strike fire suppression, we could reduce the average extinction risk to below 20% – a significant reduction.
This risk could be reduced to less than 10% with a further increase to US$120 million per year, spread fairly evenly across habitat protection and fire suppression.
This is the first time (we think) that anybody has been able to quantify the marginal benefits of increasing conservation spending in terms of reducing extinction risk to species; something we believe to be a very powerful policy tool.
How will it work in Australia?
So, what does this all mean for Australian species and how we should be managing ecosystems in order to reduce climate-change driven extinctions?
The first point to make is that conservation investment questions faced by managers of the fynbos are very similar to those faced in Australia and in other parts of the globe.
Namely, how should I allocate my limited budget across a set of possible management actions to achieve the best conservation outcome?
The Fynbos Biome is known as a “Mediterranean” climate ecosystem, similar to ecosystems in Australia, including the biodiversity hotspots in south-western Australia.
The impacts of climate change on fire dynamics and how those changes will impact Australian species are important questions that are currently being addressed by a number of Australian scientists.
We hope to be able to work with these experts to implement the sort of ecological-economic analyses described above.
Although ecological-economic analyses such as ours provide just one of many inputs to real-world decision-making, more widespread application of these approaches will help reduce the politicisation of conservation decisions, thereby enhancing the credibility of those who make them.
For more information about Brendan’s research, watch the video that featured on the 7pm bulletin of ABC News Melbourne on September 19.