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A Mathematical Formula for Conservation

Liz Clift, MFA

“Finding beauty in a broken world is creating beauty in the world we find.” – Terry Tempest Williams, from Finding Beauty in A Broken World

Recently, I was walking into a symposium on Urban Ecological Design and Restoration with one of my coworkers. I don’t remember how we got on the subject, but just before we walked in the doors, I said “Just the fact that the blue whale exists – that we are living at the same time as the biggest animal that has ever lived on Earth – makes me happy.”

My undergraduate environmental economics teacher would have jumped all over this, asking me to assess intrinsic and extrinsic values to the existence of blue whales (Balaenoptera musculus), and then brought whatever answers I gave into less-romanticized reality by asking how much I would personally be willing to give (in money and in time which would be assigned a monetary value) to save the blue whale. He would have engaged me in a conversation about whether my answer would change if there was only one or even 100 blue whales left in the world compared to the 10,000-25,000 currently believed to still exist.

My co-worker didn’t ask any of those questions, but brought up the panda (Ailuropoda melanoleuca).

Mathematical Formula for Conservation

It’s easy for us to talk about conservation when we’re talking about species that are well-known:  charismatic megafauna (pandas or blue whale, for instance) or species who we’ve designated (officially or unofficially) as national icons, such as bald eagles (Haliaeetus leucocephalus) and koalas (Phascolarctos cinereus).

It’s much harder when we talk about the conservation of less widely known species. Some of these species might be newly discovered, or considered “pest” species, or perhaps have just never had a strong advocacy group encouraging all of us to care. These species may or may not be keystone species. They may or may not be crucial to successional growth in an ecosystem. They may or may not be a lot of things.

Ultimately, this comes down to a question of the ways we place value on living things. More specifically, we have to determine how, given limited conservation funds, we determine which species we should work to conserve.

Project Prioritization Protocol (PPP) offers a mathematical solution to help us determine this. The idea was first advanced by economists Andrew Metrick and Martin L. Weitzman in 1998, and was further developed by Hugh Possingham at the Queensland University Centre for Excellence in Environmental Decisions. It has been adopted by the governments of New Zealand, and New South Wales (NSW), in Australia, as a way to prioritize which species receive limited conservations funds.

In New Zealand, which has been running this type of program for about 6 years, priority was placed on preserving the greatest possible number of species that are endemic to New Zealand. To try and limit community objections to this way of prioritizing species, the initial project included community consultation, including with NGOs, Maori tribal representatives, and the public at large. In addition, project leaders decided to allocate a certain amount of conservation funds to species that are iconic to New Zealand, and exclude those species from the PPP process.

NSW’s project, Saving Our Species (SOS), which began more recently, focused on maximizing the number of threatened species that could be maintained in the wild over the next 100 years. Higher priority animals included the masked owl (Tyto novaehollandiae) and the yellow spotted bell frog (Litoria castanea), while a lower priority species was the purple crowned lorikeet (Glossopsitta porphyrocephala).

The mathematical formula used to prioritize species relies on converting the benefit of a species surviving to an economic value. This may be based partly on dollars added to the economy (for instance, koalas are an integral part of the Australian tourist economy, estimated to add AU$1.1 – 2.5 billion to the economy) and partially by monetizing the value of the species’ role in the ecosystem. This is multiplied by the benefits of the program and the probability of the conservation program’s success, then divided by the program cost.

In short, the formula looks like:

Mathematical Formula for Conservation

W = Species value

B = Benefits of the project

S = Probability of success

C = Project cost

Critics of PPP are reluctant to accept some extinctions as inevitable. It probably doesn’t help that the focusing of conservation resources is sometimes referred to as “conservation triage.” Michael P. Nelson, an environmental philosopher and ethicist, finds the term triage problematic because he opposes celebrating the recovery of one species if it means the failure to save another due to limited resources. Further, Nelson acknowledges that while conservation resources might be scarce for a particular agency, they are not – at least in the US – genuinely scarce; we are just choosing not to allocate funds toward conservation. Like other critics, Nelson implies that if governments are serious about conservation, they would put more money toward it.

Of course, it’s never that simple. We live in a world in which we are on the verge of another mass extinction. And, we also live in a world where funding for conservation programs is limited, and often divided among many competing groups who are advocating for a variety of different species. One potential benefit of this mathematical formula is that it allows for the conservation of species who may be critical to an ecosystem – but might not have loud voices advocating on their behalf.

As any economist would tell you, we are always assigning value – in this case, to various species (not to mention the conservation and restoration projects often associated with helping maintain a particular species) – the PPP just makes it more explicit.

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