SUBJECT: Ecological value of biodiversity
AUTHOR: Martin Sharman
DATE: 3rd April 2003

KEYWORDS: Ecological value, buffering, providing reasons for governance.

SUMMARY: Can we use the ecological value of biodiversity as an argument to encourage the development of policies that seek to protect biodiversity? Probably not, because the evidence before our eyes is that progressively simplified systems persist - until they abruptly collapse.

John Hutcheson believes that "there is a scientifically demonstrated ecological value of biodiversity". I would be flying in the face of reason (and evidence) to deny that life creates and maintains conditions suitable for life or that life buffers physical parameters. This is not my argument.

I suspect that our disagreement may stem from his perception of biodiversity as 'life' and my perception of biological diversity as 'a characteristic of life'. But I feel that there is another point here, to do with governance and what reasons we give in support of our belief that we must develop human survival systems that conserve biodiversity.

What concerns me is that we can take an ecosystem (for example, a forest) and progressively simplify it by removing species, or reducing biodiversity in some other way, perhaps by reducing the populations of the most common species, or removing certain phenotypes. For a long time, the buffering that John talks about means that the forest will maintain some kind of ecological integrity as this reduction in biodiversity continues. We probably all know at least one forest - or other ecosystem, the ocean being the most glaringly obvious one - that is going through this slow transformation. The loss of each single species may bring about a small cascade of other losses, but can we say that the diversity itself (as distinct from any of its components) has scientifically demonstrated ecological value?

At some point, perhaps, we will remove one species too many, and an ecological catastrophe will follow and the forest (or fertile ocean) will be transformed into something else. At that cusp, nobody could possibly deny that biodiversity has ecological value. Unfortunately we will almost always discover the phase space location of that cusp too late.

And this is my worry about such a functional reason for defending and cherishing biodiversity - we can go on pulling away the pillars from under the pier for a long time, without anything terribly dramatic happening. Anyone who tries to warn against this kind of behaviour is discounted as a doomsayer. But when the pier does abruptly collapse, what can we do except watch?

I feel that nobody should end their contribution to this conference without stating what strategically important research should be done, in support of good governance, to investigate the concerns that they raise. In that belief, here is my (partial) list of "science for good governance" for this issue:
- Understand how to define and assess ecosystem quality.
- Develop ways of managing endangered or threatened ecosystems, marginal or relict habitats, and those with low resilience.
- Understand how to evaluate the minimum area that an ecosystem must cover if it is to persist under probable scenarios of climatic and anthropogenic change.
- Understand the ecology of the deep ocean and the benthos and its response to drivers of biodiversity change.
- Develop effective low-cost methods to rehabilitate threatened species and restore degraded ecosystems.
- Last, but by no means least, better understand how to conserve biodiversity while ensuring sustainable livelihoods.

A contribution by:

Martin Sharman
European Commission
Research DG DI-4 Biodiversity and Ecosystems
Rue Luxembourg 46
B-1049 Brussels, Belgium