Evolving Thoughts

Evolution, culture, philosophy and chocolate! John Wilkins' continuing struggle to come to terms with impermanence... "Humanus sum, nihil humanum a me alienum puto" - Terence

Tuesday, December 13, 2005

Extinction, conservation, and the vertebrate bias

A new paper in PNAS [Note: it's not up as yet] suggests that we can stave off extinction of 794 endangered species by safeguarding 594 epicentres of extinction around the world. The Alliance for Zero Extinction believes that by protecting these regions we can prevent anthropogenic (that is, human-caused) extinction from progressing any further.

While I think it is a useful thing to identify these furry and feathered vertebrates under threat, it is yet another example of the vertebrate bias in much modern biology. What about all the plants that will die if their habitats are destroyed? What about the fungi, the algae, the bacteria? Life is more than big, mobile, things that have some sort of thermal protection. Ecosystems rely on all these things.

It might be argued that vertebrate species are surrogates for biodiversity in the round, but this cannot be right. The animals might persist for a while by migrating long after the viable populations of trees or nitrogen-fixing nodes in the soil are endangered in a region, and might go extinct well after their "infrastructure" has become unsupportable.

I have similar problems with the use of "genetic diversity" as a measure, in for example, the WORLDMAP project. What is it about genes that matters? Clearly it is the ability of those genes to contribute to the ecological behaviour of systems via whole organisms. Otherwise we might just as well say we should keep a genetic sample on dry ice as a way to "save" biodiversity. But nobody would suggest something that silly, would they? I mean, genes are just part of a developmental machinery, without which they'll just sit there and slowly decompose. To utilise genes properly, you need, you guessed, the organism. And to utilise the organism you have to have the ecosystem that supports it. So this is no solution either.

I wish I understood what was the solution - there is something that we measure in biodiversity measures, no matter whether it's species or population sizes or genetic diversity. But whether these things are surrogates for the "vitality" of the ecosystem, or are important in themselves, is something we need to work out. Species of things with backbones merely represents our own biases, not the biases of Nature. If we try to save things because they are obvious to us, then we may fail rather badly...