The value of ecosystem services and biodiversity conservation
Abstract
Ecosystem services are defined as “the benefits people obtain from ecosystems” (Costanza et al. 1997; Millennium Ecosystem Assessment 2005). These include provisioning services such as food and water; regulating services such as regulation of floods, drought and disease; supporting services such as soil formation and nutrient cycling; and cultural services such as recreational, scientific, spiritual and other nonmaterial benefits (Costanza et al. 1997; Daily 1997; de Groot et al. 2002). This is an appropriately broad and an appropriately vague definition. It includes both the benefits people perceive, and those they do not. The conventional economic approach to “benefits” is far too narrow in this regard, and tends to limit benefits only to those that people both perceive and are “willing to pay” for in some real or contingent sense. However, the general population’s information about the world, especially when it comes to ecosystem services, is extremely limited. We can expect many ecosystem services to go almost un noticed by the vast majority of people, especially when they are public, nonexcludable services that never enter the private, excludable market. Think of the storm regulation value of wetlands (Costanza et al. 2008). How can we expect the average citizen to understand the complex linkages between landscape patterns, precipitation patterns, wetlands and flood attenuation, when even the best landscape scientists find this an extremely challenging task? We need to remember the definition of ecosystem services (the benefits provided by ecosystems), and acknowledge that the degree to which the public perceives and understands them is a separate (and very important) question. Conventional economic valuation presumes that people have well-formed preferences and enough information about trade-offs that they can adequately judge their “willingness-to-pay”. Since these assumptions do not hold for many ecosystem services we must: (1) inform people’s preferences by showing the underlying dynamics of the ecosystems in question using models; (2) allow groups to discuss the issues and “construct” their preferences within a framework to inform the discussions; or (3) use other techniques that do not rely directly on preferences to estimate the contribution to human well-being of ecosystem services (i.e. to directly infer marginal contributions to well-being), for example through the use of computer models.