As CB readers will appreciate, I am firmly in support of the application of conservation triage – that is, the intelligent, objective and realistic way of attributing finite resources to minimise extinctions for the greatest number of (‘important’) species. Note that deciding which species are ‘important’ is the only fly in the unguent here, with ‘importance’ being defined inter alia as having a large range (to encompass many other species simultaneously), having an important ecological function or ecosystem service, representing rare genotypes, or being iconic (such that people become interested in investing to offset extinction.
But without getting into the specifics of triage per se, a related issue is how we set environmental policy targets. While it’s a lovely, utopian pipe dream that somehow our consumptive 7-billion-and-growing human population will somehow retract its massive ecological footprint and be able to save all species from extinction, we all know that this is irrevocably fantastical.
So when legislation is passed that is clearly unattainable, why do we accept it as realistic? My case in point is South Australia’s ‘No Species Loss Strategy‘ (you can download the entire 7.3 Mb document here) that aims to
“…lose no more species in South Australia, whether they be on land, in rivers, creeks, lakes and estuaries or in the sea.”
When I first learned of the Strategy, I instantly thought to myself that while the aims are laudable, and many of the actions proposed are good ones, the entire policy is rendered toothless by the small issue of being impossible.
Extinctions are, of course, a normal part of life, at least over geological time scales1,2. However, the rapidly expanding human population has put such pressure on the Earth’s resources that we have now entered the sixth mass extinction event now dubbed ‘The Anthropocene’3. In a local context, Australia has the highest current extinction rate of mammals in the world4, and we have lost nearly 40% of our forest cover since European colonisation5. South Australia in particular has seen extensive habitat loss, local extinctions and habitat degradation (you can see some of the evidence for this in South Australia’s State of the Environment reports).
That’s bad enough, but the major damage has been done and we’re now on track to rectifying the limited vision of past, right? Wrong.
Unfortunately, degradation of the past has not yet wreaked the havoc on species due to a phenomenon known as ‘extinction debt’6. This well-demonstrated component of extinction means that extinctions continue years, decades and sometimes centuries past the major environmental perturbation. Thus, even if a comprehensive, state-wide and massive ecological effort were to begin tomorrow in South Australia (another unlikely scenario), we would still be committed to decades of extinctions from past degradation. These are not wild, uncertain concepts – these are well-established facts.
Combine this notion with the observations that few, if any, of the indicators used to track biodiversity change in South Australia are suggesting improvement, and the Strategy loses credibility. It is therefore beyond avoidance that extinctions will continue in South Australia regardless of our actions. Of course, we can slow the process, but we cannot possibly meet the policy targets set by the Strategy.
Now, some people might suggest that the Strategy’s ‘No Species Loss’ title shouldn’t be taken literally and of course we cannot avoid all extinctions, but this sentiment isn’t expressed anywhere in the document. It is therefore disingenuous to the public that such a bold, yet fantastical policy exists at all. Some could also argue that a mere word change would rectify the problem – I disagree. The entire notion of triage is ignored here because it implicitly assumes that there is no hierarchy or prioritisation necessary.
My intention here is not to denigrate my respected colleagues in the State government (and I do actively work with many of them); rather, I seek to stimulate the responsible bureaucrats to listen to their employees and other experts to address these important gaps in our environmental policies. Otherwise, what happens when (and not if) we fail? Do we simply say ‘oh well’, admit defeat, and continue on as before? It seems to me that this is an overly naïve way of proceeding, and it does not embrace the fountain of ecological knowledge we have already tapped. Let’s be cleverer about how we approach biodiversity conservation.
CJA Bradshaw
References
- Raup, D. M. Biological extinction in Earth history. Science 231, 1528-1533, doi:10.1126/science.11542058 (1986)
- Raup, D. M. The role of extinction in evolution. Proc Natl Acad Sci USA 91, 6758-6763, doi:10.1073/pnas.91.15.6758 (1994)
- Crutzen, P. J. Geology of mankind: the Anthropocene. Nature 415, 23, doi:10.1038/415023a (2002)
- Johnson, C. N. Australia’s Mammal Extinctions: A 50 000 Year History. (Cambridge University Press, 2006)
- Bradshaw, C. J. A. Little left to lose: deforestation and forest degradation in Australia since European colonization. J Plant Ecol 5, 109-120, doi:10.1093/jpe/rtr038 (2012)
- Tilman, D., May, R. M., Lehman, C. L. & Nowak, M. A. Habitat destruction and the extinction debt. Nature 371, 65-66, doi:10.1038/371065a0 (1994)