What Are Slugs Good For?: Ecosystem Services and the Conservation of Biodiversity

The concept of ecosystem services was conceived as a tool for conserving biodiversity. Ecosystems, the argument goes, provide services that would be far more costly if we sought to provide them through engineered approaches; valuing the benefits that nature confers will help society more consciously evaluate the environmental tradeoffs between alternative actions. Given this objective, ecosystem services can be characterized as a surrogate for biodiversity -- a step that makes explicit the assumption that, if we conserve ecosystem services, we will conserve biodiversity. It is this assumption that is the focus of this article. Surrogates are employed when it is difficult, expensive, or impossible to measure something. An examination of the concept of biodiversity demonstrates that it is such a something. Is ecosystem services a suitable surrogate for biodiversity? A preliminary review suggests two problems. First, the spatial and temporal scales of biodiversity and ecosystem services differ substantially. Second, the utilitarian valuation that is implicit in the term services and explicit in the attempt to monetize that value also undercuts the usefulness of ecosystem services as a surrogate because it appears likely that there will always be a more efficient way to provide any specific service. Ultimately, whether ecosystem services is a suitable surrogate for biodiversity depends upon whether biodiversity has value beyond utility.