The EcoValue project draws from recent developments in the economic valuation of ecosystem services, ecological-economic database design, WWW technology, and spatial analysis techniques to create a web-accessible, GIS decision support system for the valuation of nonmarket goods and services associated with distinct land cover types. The basic idea behind ecosystem value transfer is to synthesize available information from past valuation studies and transfer these new estimates to a policy site for which no explicit valuation estimates exist. The end result is a web-based GIS valuation assessment tool capable of generating meaningful and reliable value estimates of ecosystem goods and services that can then be integrated into research, decision-making and planning.

The EcoValue research team has developed a set of decision rules for selecting empirical studies from the published literature that allow us to estimate with sufficient accuracy the economic value of ecosystem services in project sites. Using scientific data search engines such as ISI Web of Science ®, the research team periodically reviews the best available economic literature and selects valuation studies which are:

• Peer reviewed and published in journals or books
• Focused on temperate regions in either North America or Europe
• Focused primarily on non-consumptive use

Thus far, our search criteria have yielded 42 viable studies which were then inputted into a relational Microsoft Access® database. The results of each study were then standardized to 2001 U.S. dollar equivalents to provide a consistent basis for comparison .The end result was a query sensitive relational database containing 65 valuation data points.

Given the aforementioned restrictions, we believe this approach yields conservative, baseline economic values. It also means that some land cover types where no applicable peer-reviewed research exist, such as sandplains and heathlands, received no economic value estimate, even though these areas are widely recognized as having high social and ecological value.

Once the EcoValue research team has selected empirical valuation studies, inputted them into the relational database, and standardized estimates for value transfer, we assign the resulting value estimate to the appropriate land cover categories in a spatially explicit manner. The following formula is used:


Where A(LUi) = Area of i (Land Use in hectares) and V(ES_ki) = Annual value of k ES (Ecosystem Services) for each i LU (in $/ha/yr).

The final economic estimates result from carefully matching the spatial resolution and coverage of the original 'study site' with the characteristics of the 'policy site'. For example, even though many land cover types documented for the State of Maryland support pollinators and benefit from pollination services, the only available empirical research from the literature documented replacement costs for pollination services on agricultural land. We were also constrained by the quality and extent of land cover measured in the original analysis. For example, several studies estimated the economic benefits associated with water based recreation. Since the area of study was limited to the lake or river itself, we could only assign a value to water, even through the surrounding beach area or wetlands may have contributed to its recreational value.