خدمات اکوسیستم نقشه برداری : چالش های و فرصت های عملی در ایجاد ارتباط بین GIS و انتقال ارزش

In this paper, a decision framework designed for spatially explicit value transfer was used to estimate ecosystem service flow values and to map results for three case studies representing a diversity of spatial scales and locations: 1) Massachusetts; 2) Maury Island, Washington; and 3) three counties in California. In each case, a unique typology of land cover and aquatic resources was developed and relevant economic valuation studies were queried in order to assign estimates of ecosystem service values to each category in the typology. The result was a set of unique standardized ecosystem service value coefficients broken down by land cover class and service type for each case study. GIS analysis was then used to map the spatial distribution of each cover class at each study site. Economic values were summarized and mapped by tributary basin for Massachusetts and California and by property parcel for Maury Island. For Maury Island, changes in ecosystem service value flows were estimated under two alternative development scenarios. Drawing on lessons learned during the implementation of the case studies, the authors present some of the practical challenges that accompany spatially explicit ecosystem service value transfer. They also discuss how variability in the site characteristics and data availability for each project limits the ability to generalize a single comprehensive methodology.

Ecosystem services are the benefits people obtain either directly or indirectly from ecological systems (Millennium Ecosystem Assessment, 2003, page v.) The process of identifying and quantifying ecosystem services is increasingly recognized as a valuable tool for the efficient allocation of environmental resources (Heal et al., 2005 and Millennium Ecosystem Assessment, 2003). By estimating and accounting for the economic value of ecosystem services, social costs or benefits that otherwise would remain hidden can potentially be revealed and vital information that might otherwise remain outside of the economic decision making calculus at local, national, and international scales can be internalized (Millennium Ecosystem Assessment, 2005). However, achieving such an objective requires considerably better understanding of ecosystem services and the landscapes that provide them. In this paper, we present a framework for the spatial analysis of ecosystem service values (ESVs), illustrated through three case studies. Thanks to the increased ease of using Geographic Information Systems (GIS) and the public availability of high quality land cover data sets, bio-geographic entities such as forests, wetlands and beaches can now more easily be attributed with the ecosystem services they deliver on the ground (Bateman et al., 1999, Eade and Moran, 1996, Kreuter et al., 2001 and Wilson et al., 2004). This approach compliments the other transfer techniques discussed in this Special Issue of Ecological Economics. The ability to integrate biophysical and ecosystem service valuation data is a relatively new phenomenon (Kreuter et al., 2001 and Wilson and Troy, 2005). Rather than argue for a single unified methodological approach that can apply to all possible circumstances, our goal is to outline a set of decision rules that have served as the basis of our efforts in three case studies. This paper first briefly reviews previous efforts to classify and place economic values on ecosystem services associated with natural and semi-natural landscapes in a spatially explicit manner. Second, it describes our decision making framework for conducting spatially explicit value transfer by linking analyses of non-market economic valuation data and biophysical data. Third, it describes how this framework was applied to three case studies. Fourth, it discusses limitations, including the potential variability of each implementation. The paper concludes with observations on current trends and expected future directions in spatially explicit ecosystem value transfer.