Spatially explicit return on investment to private forest conservation for water purification in Indiana, USA

Conservation programs that incentivize the increased provision of ecosystem services on private lands have become common policy instruments. The forgone revenues implied by these programs and the ecosystem services benefits they provide might be spatially heterogeneous. However, such programs are not always spatially targeted to maximize the return on conservation investment (ROI). Here, we use an integrated spatial, ecological-economic modeling approach to assess the ROI for water purification in the case of the Indiana Classified Forest and Wildlands (CFW) Program, United States. We compared the ROI of the existing non-spatially targeted CFW expansion to hypothetical, spatially targeted expansion scenarios in the White River Basin of Indiana. First, we projected nutrient retention services to increase greatly under the hypothetical spatially targeted scenarios and modestly in the non-spatially targeted, baseline case. Second, our results revealed the inclusion of conservation costs could substantially change the conservation priorities. In particular, private forestlands in subwatersheds with average conservation benefits and low conservation costs, as opposed to those with high conservation benefits and high conservation costs, would be prioritized for the CFW program, based on their positive ROIs. Third, we found that the benefits from the single ecosystem service of nutrient retention could exceed the conservation costs of the tax deductions and forgone alternatives (i.e., agriculture) if the program was targeted to contaminated watersheds. This research contributes to the integration of forest economics, forest conservation, and forest ecology to assess the effectiveness of forest conservation programs such as the CFW. It also informs citizens and governments on the benefits and costs of potential targeted increased enrollments of the CFW program in Indiana.