In this paper we describe the US Environmental Protection Agency’s Southwest Ecosystem Services Program (SwESP) initial efforts to use the InVEST (Integrated Valuation of Ecosystem Services and Tradeoffs) tool to quantify and map the values of multiple ecosystem services in the San Pedro Basin, Arizona, USA.  The San Pedro River originates in northern Sonora, Mexico and spans the U.S. – Mexico border into southeastern Arizona.  The Basin supports one the most ecologically diverse regions in the world.  Nevertheless, several growing communities, the Cananea copper mine (Mexico) and Fort Huachuca (Arizona) rely upon regional groundwater.  The InVEST tool is a new spatially explicit modeling tool developed by the Natural Capital Project that runs as script tools in the ArcGIS 9.2 ArcToolBox. 

Results/Conclusions Currently, biodiversity, carbon storage and sequestration, managed timber production, water pollution regulation and sediment retention for reservoir maintenance can be modeled using InVEST based upon various data types (e.g., land use /land cover, nutrient loading coefficients, soil depth) and expert input.  InVEST is designed for use as part of an active decision-making process where models are used to estimate the amount and value of ecosystem services that are available on the current landscape or under future scenarios (i.e., alternative land uses and/or climatic conditions).  The development of InVEST is ongoing and has just been recently released for public use in “beta form”.  The beta version has been applied in several sites globally yet has not been implemented in an arid region such as the San Pedro Basin. We will discuss the efficacy of using the InVEST tool using data that is currently available through the San Pedro Geo-Data browser.