Chasing Biodiversity Off the Scientific and Conservation Tracks

Abstract

The idea of conserving biodiversity has become central to the very meaning of biological conservation---in the public imagination and for conservation organizations worldwide. Identification of conservation with biodiversity conservation owes extensively to the idea that warrant for biodiversity's conservation is anchored in the empirical thesis that biodiversity causally determines ecosystem functioning, and thereby, somehow, important ecosystem services. This idea has fueled an enormous research program dedicated to producing the requisite causal evidence. This essay first reviews the data that are supposed to constitute direct evidence for biodiversity's causal influence. It proceeds by answering a heretofore unasked, yet foundational, question for causal hypotheses: Do these data meet basic requirements for credibility as causal evidence? By virtue of mistakenly reading causal significance into (i) massive numbers of causally irrelevant data points, (ii) an equation that simply equates a stipulated definition to an algebraically equivalent expression, and (iii) correlations produced by arbitrary computations over previously collected data sets, these data fall well short of meeting these requirements. Mistakes also suffuse the notion that biodiversity's supposed causal influence gives reasons to conserve it. These mistakes are exposed when the conservation argument that was supposed to proceed from the premise of biodiversity's causal influence is clearly spelled out. Once made explicit, each step is seen to rely on a questionable assumption, invalid logic, or both. The essay concludes with implications for conservation, biodiversity research, and scientific inquiry more generally.