Wetlands provide a range of services that benefit humans. Estimating the total economic value of wetlands requires accounting for all of these services, even though most are not monetized through markets. Wetland values fall under four main categories (Boyer and Polasky 2004): (1) direct use values such as recreation and provision of food or fuel; (2) indirect use values such as nutrient retention, flood control, climate stabilization, and water filtration; (3) option value derived from potential future uses; and (4) existence values such as maintaining biodiversity and cultural heritage. Advances in nonmarket valuation have made it possible to estimate the value for many of these services in monetary terms, which can be summed to arrive at an estimate for total economic value.
