Modelling multiple ecosystem services, biodiversity conservation, commodity production, and tradeoffs at landscape salces
Nelson, E. et al. 2009. Front Ecol Environ 7(1): 4-11
This paper attempts to shift the focus of ecosystem services valuation from quantification of the current net value of ecosystem services toward prediction of the future services provided under alternate development scenarios. The authors propose the analytical tool InVEST (Integrated Valuation of Ecosystem Services and Tradeoffs), which models spatially explicit land-cover scenarios, as a method to evaluate benefits and tradeoffs between different values (e.g. commodity prices, biodiversity conservation, water quality, soil conservation, and carbon sequestration) to assist with region-wide planning.
In the case-study analyzed (Willamette Valley, OR) the Conservation option improved all values at higher rates than the other options, except the market value of commodities. Surprisingly, all of the scenarios enhanced biodiversity conservation above current levels. None of the options evaluated were extreme, due to the high value of conservation in Oregon and the area's long history of crop production which was viewed as highly unlikely to change drastically. I would expect that in other regions, such as the California Central Valley, the options would contain more stark contrasts and tradeoffs would become more apparent.
The authors did find that a development policy that focused solely on commodity prices disadvantaged ecosystem service provision and biodiversity, but that such trends were mitigated by policy options (such as payment for carbon sequestration) that incentivized conservation by private landowners. They advocate this method as a way to make the outcomes of different landuse options more transparent to stakeholders.
The authors utilized generalized measurements to build their models that were not regionally specific, thus there may be localized variables that were not accounted for that could be lost in such a coarse-grained analysis. While it was acknowledged that ecosystem services would not be evenly conserved across the landscape (due to isolation and intensification effects), the metrics used tended to homoginize effects for the region, again, potentially hiding the loss ecosystem services in particular locales within the study area.
Image Credit: United Nations Environment Programme