Lazo Jeffrey K
Stratus Consulting Inc., P.O. 4059, Boulder, CO 80306-4059, USA.
Drug Chem Toxicol. 2002 Nov;25(4):349-74. doi: 10.1081/dct-120014788.
Ecosystems provide a wide range of services that improve human welfare. Changes in ecosystems imply potential changes in the generation of these ecosystem services and thus changes in welfare. In the lingo of economists, these welfare changes are measured as changes in economic values--increases in welfare being benefits and decreases in welfare being costs. For instance, individuals may benefit from, and thus value, reductions in risks to endangered species. Yet values for many changes in ecosystem services are not captured in market transactions, and thus measuring these values requires nonmarket valuation methods. This paper discusses ecosystem services and values from the viewpoint of an economist, explains what is meant by the valuation of ecosystems, and provides an overview of methods for valuation of ecosystem services. An example is presented from a recent natural resource damage assessment--the Green Bay total value equivalency study. Resources in the Lower Fox River and Green Bay in Wisconsin have been injured by polychlorinated biphenyl contamination from numerous paper mills along the river over several decades. The Green Bay study examines individuals' preferences and values for reducing ecosystem risks and improving ecosystem services and how these values are related to individuals' awareness of and use of ecosystem services in the area. The study uses methods from nonmarket valuation to scale potential restoration projects.
生态系统提供了广泛的服务，这些服务改善了人类福祉。生态系统的变化意味着这些生态系统服务的产生可能发生变化，进而导致福祉的变化。用经济学家的行话来说，这些福祉变化是以经济价值的变化来衡量的——福祉增加即为收益，福祉减少即为成本。例如，个人可能会从濒危物种风险的降低中受益，从而重视这种降低。然而，许多生态系统服务变化的价值并未在市场交易中体现出来，因此衡量这些价值需要采用非市场估值方法。本文从经济学家的视角探讨生态系统服务和价值，解释生态系统估值的含义，并概述生态系统服务估值方法。文中给出了一个近期自然资源损害评估的例子——格林湾总价值等效性研究。威斯康星州下福克斯河和格林湾的资源在过去几十年里受到了沿河众多造纸厂多氯联苯污染的损害。格林湾研究考察了个人对于降低生态系统风险和改善生态系统服务的偏好及价值，以及这些价值如何与个人对该地区生态系统服务的认知和使用相关。该研究采用非市场估值方法来评估潜在的恢复项目。
