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Assigning Unit Values in Ecosystem Services Valuation: A Comparative Analysis of Global, Regional, and Local Unit Values for Three Ecosystem Services in the Grand River Watershed, Ontario, Canada
Aziz, T.; Nimubona, A.-D.; Van Cappellen, P. Comparative Valuation of Three Ecosystem Services in a Canadian Watershed Using Global, Regional, and Local Unit Values. Sustainability2023, 15, 11024.
Aziz, T.; Nimubona, A.-D.; Van Cappellen, P. Comparative Valuation of Three Ecosystem Services in a Canadian Watershed Using Global, Regional, and Local Unit Values. Sustainability 2023, 15, 11024.
Aziz, T.; Nimubona, A.-D.; Van Cappellen, P. Comparative Valuation of Three Ecosystem Services in a Canadian Watershed Using Global, Regional, and Local Unit Values. Sustainability2023, 15, 11024.
Aziz, T.; Nimubona, A.-D.; Van Cappellen, P. Comparative Valuation of Three Ecosystem Services in a Canadian Watershed Using Global, Regional, and Local Unit Values. Sustainability 2023, 15, 11024.
Abstract
Economic valuations of ecosystem services often transfer previously estimated global unit values to the geographical setting of interest. While this approach produces quick results, its reliability depends on how representative the large-scale average unit values are for the given local context. Here, we estimate the values of three ecosystem services (ES) – water filtration, nutrient cycling and carbon sequestration – in the Grand River watershed (GRW) of southern Ontario, Canada. The watershed covers nearly 7000 km2, has a humid continental climate and a population of close to one million people. Land cover is dominated by agriculture. We compare ES valuations using locally derived (i.e., GRW-specific) unit values to valuations based on unit values from a regional database and those compiled in the global Ecosystem Services Valuation Database (ESVD). The regional database includes mean unit values from three case studies within southern Ontario and one boreal watershed in British Columbia. As expected, the regional database yields average monetary values for the three ES that are close to those obtained with the local unit values but with larger associated uncertainties. Using the ESVD, however, results in significantly higher monetary values for the ES. For water filtration, the ESVD value is more than five times higher than the regional and local estimates. We further illustrate the effect of the extent of aggregation of forested and agricultural land categories on the ES values. For example, by subdividing the forest category into three sub-categories (deciduous, coniferous, and mixed forest), the estimated value of the carbon sequestration ES of forested areas within the GRW increases by 15%. Overall, our results emphasize the importance of critically assessing the origin of unit values and the land cover resolution in ES valuation, especially when the latter is used as a policy-guiding tool.
Keywords
Ecosystem Services; Value Transfer Method; Replacement Cost Method; Unit Value Database; Land Cover Resolution; Grand River Watershed
Subject
Environmental and Earth Sciences, Environmental Science
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
