(Dec. 22nd, 2009) How do you decide what to save when you know it needs saving? Is it economic folly to try to prevent further extinctions? Even when consensus agrees that species are doomed without direct intervention, the scientific debate on preventing extinction is caught up in thorny questions of ‘economic reality’. Just how many species can you save with limited financial resources? By Jeremy Garwood.
Indeed, do those who carry out detailed economic analyses make realistic choices or are they surrendering to a logic that views endangered species as too costly to maintain? In conservation circles, the most prominent advocate of economic realism is an Australian, Hugh Possingham, from The Applied Environmental Decision Analysis Centre at the University of Queensland. Working from the ‘pragmatic’ viewpoint that you can’t save everything with the existing conservation budgets, Possingham has advocated the development of ‘efficient’ management models that provide a clearer analysis of the economic costs and benefits associated with potential conservation projects. He argues that until you have a systematic means of comparing the costs and likely outcomes of different projects, you cannot efficiently decide how best you spend your money.
Conservation Triage – Selecting the Survivors.
In a direct challenge to alternative approaches, Possingham has compared the choice of species conservation to the practice of ‘triage’, when battlefield victims are swiftly divided into those who have a high chance of survival if medically treated and those who are too fatally wounded to justify the effort.
“Is conservation triage just smart decision making?” he asks in Trends in Ecology and Evolution (2008, vol.23, 649-54). For Possingham, ‘triage’ is a process of prioritization. In a medical context, triage “is used to allocate limited resources for the greatest good for the largest number of people”. The treatment of patients is prioritised by injury severity, the consequence of delaying treatment, net benefits of different treatments and the probability that the patient will recover with or without treatment. “Triage is no more than the efficient allocation of conservation resources and we risk wasting scarce resources if we do not follow its basic principles.”
As an example of the benefits of triage, he presents a ‘hypothetical’ scenario: there are five islands where native ground-nesting birds are severely threatened by predation from introduced black rats. If nothing is done, the rats will eradicate the bird species. But with only $50,000 over 10 years, how can the conservation manager best achieve his aim of saving the birds? The obvious solution is to completely eliminate all the rats. However, if the manager tries to simultaneously spread his funds over all five islands, there is a real risk that if any rats survive to repopulate the islands, the project will ultimately be a failure. Well, says Possingham, using conservation triage, the manager would first determine on which of the islands he has the highest chance of achieving success and then concentrate all his resources to saving that island’s birds. If he succeeds in completely eliminating the rats from that island, he can then begin to work on the next island – perhaps his first success will even be rewarded by extra funding!
Zero Extinction!
Not everyone agrees with Possingham’s approach, notably the ‘Alliance for Zero Extinction’, a worldwide partnership of 67 biodiversity conservation organisations, which aims to prevent extinctions by identifying and safeguarding key sites where species are in imminent danger of disappearing (currently over 700 sites). The goal of the Alliance is to “create a front line of defense against extinction by eliminating threats and restoring habitat to allow species populations to rebound” (www.zeroextinction.org).
Possingham’s roundly detractors argue that use of triage in conservation promotes defeatism when an asset is deemed too difficult to save, that his approach will result in protection of “only moderately diverse, moderately threatened biodiversity assets.” Or that “urgency, i.e. extinction risk, is a catalyst for scientific innovation, and that scientists demonstrate their intellectual mettle when time is running outand extinction appears imminent.” He condemns their lack of realism about the ‘astronomical’ amounts of money required to reverse the extinction rate for all biodiversity. He told Nature that conservation managers weren’t rigorous enough, that not everything can be saved: “A lot of people get upset with that. Basically some regions aren’t working at all. They are too expensive, the threats are too huge, or there are not enough species in them” (‘What to Let Go’, 2007, vol 450, 152-155).
The Alliance for Zero Extinction (AZE) replied that: “the cost of effective global diversity is only ‘astronomical’ in one sense – being the same order of magnitude as current resources for space exploration” (‘Why we should aim for zero extinction’, Trends in Ecology and Evolution, 2009, vol. 24, 181). They say their sites contain 95% or more of the known population of an endangered species. “Conservation reality departs from triage theory when deciding which patients to treat and which not. Predicting possible survival is far less certain for a threatened species than for a human patient and we usually have much more time for intervention than would battlefield doctors.” If a narrow triage approach had been followed, projects that have already proved successful in saving species would probably not have been adopted.
Furthermore, they say interventions do not have to be costly to work, with examples ranging from private reserve networks to community-based conservation and outreach programs, to captive-breeding and reintroduction projects, and ecotourism developments. Naturally, more money would be welcome: “considering that the amounts needed to protect all AZE sites are insignificant in comparison to the economic packages currently being discussed for the US auto industry alone”!
A triage choice: Do you save 1 Kiwi species instead of 1 fish, 1 invertebrate, 3 plants and another bird species?
Possingham remains an unrepentant economic realist: “Conservation funds are grossly inadequate to address the plight of threatened species” and governments and conservation organisations need “simple strategies for allocating limited resources”, he writes in an ambitious paper in which he dissects the entire national conservation program for threatened-species projects in New Zealand (‘Optimal allocation of resources among threatened species: a Project Prioritization Protocol’, Conservation Biology, 2008, vol 23, 328-38).
32 species projects were assessed for relative costs and benefits (including species values based on taxonomic distinctness and whether it holds a key role in the ecosystem) and the likelihood of management success (as assessed by 105 ‘experts’). His stark conclusions are unlikely to please groups like AZE:
1. Ranking species by taxonomic distinctiveness always resulted in the fewest species managed.
2. Prioritizing projects on the basis of threat status or taxonomic distinctiveness produced the lowest expected benefit.
3. Ranking species by threat status consistently selected a set of species with the lowest summed uniqueness.
4. Ranking projects by the species threat status performed poorly across all budgets because this ranking method produced very low expected gains in uniqueness.
Specifically he notes that if his method were applied he could ‘save’ six additional species, including 3 plants, a bird (the Chatham Island Oystercatcher), a fish (Cantebury mudfish), and an invertebrate (the Cook Strait giant weta) for the same price as the highly taxonomically distinct North Island brown kiwi bird. Which leads him to pose the question: “Is funding this species worth sacrificing 6 other species, even if each is individually relatively taxonomically indistinct?”
Possingham’s hard-headed economic realism and use of economic terminology is increasingly influential with public funding agencies. When reading his observations about the future of endangered New Zealand wildlife (funded by the NZ Department of Conservation), it is easier to understand why conservation groups like AZE are worried about Possingham’s potential triage. The North Island brown kiwi bird is already threatened in its natural environment, could the application of triage spell out its final demise?
In the final part of this series, Jeremy Garwood considers studies that are principally concerned with the possible extinction of just one species – Mankind. Featuring assessments on the planetary limits defining a viable biosphere and an economic cost-benefit analysis justifying the long-term preservation of Homo sapiens.