Modelling the supply of ecosystem services from agriculture: a minimum-data approach

We argue that to support agriculture–environmental policy decision making, stakeholdersneed ‘quantitative back-of-the-envelope’ analysis that is timely and sufficientlyaccurate to make informed decisions. We apply this concept to the analysis of the supplyof ecosystem services from agriculture. We present a spatially explicit productionmodel and show how it can be used to derive the supply of ecosystem services in aregion. This model shows that the supply of ecosystem services can be derived fromthe spatial distribution of opportunity cost of providing those services. We then showhow this conceptual model can be used to develop a minimum-data (MD) approachto the analysis of the supply of ecosystem services from agriculture that can be implementedwith the kinds of secondary data that are available in most parts of the world.We apply the MD approach to simulate the supply of carbon that could be sequesteredin agricultural soils in the dryland grain-producing region of Montana. We findthat the supply curve derived from the MD approach can approximate the supplycurve obtained from a more elaborate model based on site-specific data, and can doso with sufficient accuracy for policy analysis.