How do we choose what species to conserve?

Conservation biologists have long had to admit that we can’t conserve everything on the planet. There is neither the political will, public support, or funding to do so. Therefore, we have to focus on what we want to conserve, while making sure that our choices are broad enough to ensure that the goal of conservation of the most species is achieved.

Once you talk with several conservation biologists, you quickly realise that there are varying rationales behind conservation. Some want conservation of biodiversity merely for aesthetic and “spiritual” purposes; others focus on the economic benefits of biodiversity; the ones I agree with the most want conservation of biodiversity as study materials for ecology and evolutionary biology.

Such phylogenetically-minded conservationists consider three options to focus on conserving:

  • Basal taxa: These are taxa that are at the base of a phylogenetic tree, and which therefore hold the most information on the evolution of the higher taxa.
  • Speciose taxa: These are taxa that have many species in them, their success meaning they are easier to conserve.
  • Phylogenetic diversity: This approach is the most sensible one and seeks to conserve as broad areas of the phylogenetic tree as possible. So, for example, instead of concentrating on the basalmost taxa and the most divergent ones, we should choose select groups spanning the phylogeny so as to maximise the conserved diversity.

When it comes to actually choosing species, one must also consider ecology and the role of the species in its ecosystem. For example, a species can be a keystone species or a foundation species.

  • Foundation species, as the name suggests, are those that are foundational for the functioning of their ecosystems, and play an ecologically disproportionate role compared with other species.
  • Keystone species are those whose role they play in communities causes them to have a large effect on other species in the ecosystem. Keystone species are mostly predators and ecosystem engineers (most famous among those are ants, termites, and beavers).

Targeting such species for conservation seems like the best idea, since conserving them will automatically lead to the conservation of the entire ecosystem they live in. This does present some challenges, though. Kelp forests count as ecosystems on their own, but how does one decide what is a kelp forest and merely a patch of kelp? Small patches of kelp are of negligible importance and in those cases, the kelp doesn’t count as a foundational species. Similarly, the presence of even a small amount of starfish in a marine benthic ecosystem will have a drastic effect (starfish are a keystone species), but how do we go about conserving them?

At this point, you may be asking yourself why we focus on species rather than ecosystems. And that is a very valid question. The answer is that conservation must deal with a lot of politics and public relations. Often, the goal of conservation is precisely to conserve an entire ecosystem, as we do with natural preserves. However, it is difficult to seek protection for something so large and hard to advertise.

Consider yourself an advertiser wanting to preserve bamboo forests in China. You could hire a film crew, go on a trip to China and film beautiful scenes of sunlight streaming through the bamboo, with a rich choir of insects and soothing sounds of nature dubbed over the footage. Or… you can buy a standard camera, take a picture of a panda, and slap that on a poster and make it go viral on the internet. I guarantee you the latter is by far the easier and more (cost-)effective solution.

So, we pick charismatic flagship species as banners for conservation. These are “cute” and otherwise aesthetically-pleasing animals that everyone would pay money to conserve. African megafauna, pandas, whales and dolphins, parrots, monkeys, etc. are common targets of such PR. Public support drives governmental support, leading to funding and at least a half-assed commitment. And, in doing so, the ecosystem that these animals live in gets preserved. Goal achieved.

This is why conservationists must be careful when choosing these flagship species. Typically, we will choose an umbrella species, one whose range covers the entire area that we want to conserve, so that conserving it will also lead to the conservation of other species that overlap ecologically with it.

And this is how we tie back to the earlier aspect of phylogenetically-minded conservation. The animals that need the most conservation aren’t vertebrates. They’re insects, they’re fungi, they’re plants. Yet conservation posters are plastered with photos of vertebrates, because that’s what the public relates to the most. And by conserving the vertebrates and the ecosystems they live in, we’re also conserving all the microfauna and the rest that needs to be conserved to maintain a high phylogenetic diversity.

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