Refocusing on nature: holistic assessment of ecosystem services.

The benefits people obtain from ecosystems vary from direct benefits that are easily monetized (e.g., timber) to indirect benefits that are not easily monetized (e.g., maintenance of water quality). Commonly, there is wide variation among individuals in the values placed on ecosystem benefits or services. The lack of consensus both in identifying ecosystem services and in valuing them with respect to other services poses a great challenge to those charged with evaluating changes in the provision of ecosystem service after, for example, a natural disaster. Natural resource economics provides some tools, but economics alone will not ensure a balanced, holistic assessment. An inherent complexity in valuing services is often associated with the interrelationships between services and the background and expertise of those leading the assessment. We argue that a holistic evaluation of ecosystems founded on solid expertise in ecosystem dynamics is essential for the accurate assessment of ecosystem services. A reductionist approach to ecosystem service valuation often fails to capture ecological dynamics that are vital to the functioning and ultimate provision of services. In this article, we present case studies of ecosystem services valuation for forest fires, dam removal, and chemical contamination of sediment to explore the complexity of ecosystem service valuation. Additionally, we offer assessment strategies for recognizing the importance of holistic assessment of ecosystem services.