Cover of “What is Biodiversity?”

Below is the another installment on the philosophical and ecological values of biodiversity motivated by the University of Oregon lecture series titled “Biodiversity at Twenty-Five: The Problem of Ecological Proxy Values”. In the first set of posts, Tim Christion Myers investigated the value of biodiversity conservation through the eyes of a philosopher, while Lorien Reynolds reflected on the value of biodiversity through the eyes of an ecologist. The next set of posts was motivated by Dr. David Hooper’s presentation and interdisciplinary workshop on biodiversity and compared the views of biology grad student Lucas Nebert and environmental studies grad student Shane Hall. Here, philosophy student Jon LaRochelle reflects on a presentation by Kim Sterelny, asking whether biodiversity is a an appropriate conceptual framework for conservation.

If conservation biology is triage, how are we to make intelligent decisions about what to save and what to let go?  “How do we do something to stem the tide of human resource consumption in a targeted and principled way?”

This is the question Kim Sterelny used to frame his philosophical work on biodiversity during his visit to the University of Oregon’s “Biodiversity at Twenty-Five” seminar series.  Six years after the publication of his book with James Maclaurin, What is Biodiversity?, Sterelny came to Eugene to reflect on that project and his current thinking on the concept of biodiversity.  Was their attempt to conceptually clarify “biodiversity” successful?  Does biodiversity continue to be a viable metric for decisions in conservation biology?

According to Sterelny, “biodiversity” should be both 1) theoretically principled and 2) empirically tractable if it is to effectively guide conservation triage.

1) Theoretically principled — “Biodiversity” should identify an aspect of a system that is a robust and causal driver of that system.  This stands in contrast to explicitly normative accounts of biodiversity (i.e., “Biodiversity is intrinsically valuable”), and conventionalist accounts (see, for instance, Sahotra Sarkar’s “Defining ‘Biodiversity’; Assessing Biodiversity”).  The diversity stability hypothesis is one such theoretically principled account, which ties the value of biodiversity to the stability of an ecosystem.  Sterelny and Maclaurin (2008) see this as a plausible account, though not yet fully demonstrable (see especially pp. 119-123).

2) Empirically tractable — Biodiversity should be a measurable property of a system.  Practically, we should be able to look at an ecosystem and measure biodiversity well enough that the measurements can guide conservation decisions.  This is a severely limiting condition, since measures of biodiversity will almost always be indirect, partial, or both.  Sterelny stresses the importance of surrogates.  Rather than measure biodiversity itself—a daunting task—we might hope to identify viable surrogates, easier to measure but reliable enough for making choices about conservation.  Two such surrogates are species richness and phylogenetic variation.  Sterelny and Maclaurin advocate a pluralist approach to biodiversity, which sees it as varying both across and within systems depending on one’s purposes.

To meet these two conditions, Sterelny and Maclaurin argue for a conception of biodiversity that stresses species richness supplemented by consideration of phylogenetic and phenotypic diversity.  Using this specification of “biodiversity,” conservation decisions can be made based on option value—barring definitive knowledge about the species’ relative value, we should hedge our bets and conserve as diverse a swath of the history of evolution as we can, so as to keep our options open for future crises.

Revisiting the project six years later, Sterelny still stands by their account of species richness as the best candidate for a framework concept to guide the inescapable work of conservation triage.  However, he expressed some hesitation about whether the development of such a framework concept is possible.  In the Q&A, biologists and philosophers alike pressed him on the continued viability of “biodiversity.”

Listening to the talk and ensuing discussion, I was left wanting a further discussion of value.  What values should guide our thinking about the human relation to the natural world?  Is biodiversity up to the task we’ve set for it?  Conceptual clarity aside, is biodiversity the right value for guiding the human relation to the natural world?  Is it the right value from the perspective of the natural world itself?  Sterelny’s work nicely articulates the conditions that must be met for biodiversity to do what we ask of it, but he himself expresses doubts about its continued normative viability.

What is called for is further reflection on the values that guide conservation.  “Biodiversity” is theoretically fraught but intuitively appealing.  The Tuatara is a fascinating animal which has intuitive conservation appeal, but may not have very high option value.  Should we conserve it anyway, because it is a fascinating relic of the evolutionary past?  Could conservation resources be better spent? To what extent does the perspective of the tuatara, or some other endangered species, count as a matter for consideration.  Sterelny does good conceptual work on “biodiversity” while leaving these value questions largely unanswered.  However, it is precisely these questions that call for consideration.

October 15, 2014