ENERGY DEVELOPMENT CHANGES ECOSYSTEM SERVICES AS MODELED BY INTEGRATED VALUATION OF ECOSYSTEM SERVICES AND TRADEOFFS (InVEST) IN THE GREEN RIVER BASIN, WY

Ecosystem Services are the benefits humans derive from natural systems. Studies of ecosystem services attempt to understand how ecosystem services are generated, consumed, and flow through space and time, as well as establish methods for estimating their monetary and nonmonetary value. Ecosystem services, by allowing comparisons of costs and benefits, creates a framework for decision making and understanding human impacts on landscapes and the ecosystems they harbor. InVEST estimates ecosystem services with an open source set of tools that run within ArcGIS. Each module allows coarse estimation of a suite of variables for a particular ecosystem service. InVEST allows scenario comparison and has been used in a number of decision making contexts.

We applied InVEST to assess the effects of Coal-Bed Methane (CBM) production on a subset of ecosystems services in Southwest Wyoming. Secondarily, we investigated the utility of InVEST as an ‘off the shelf’ modeling platform. We mapped the disturbance caused by CBM extraction in 1994 and 2007 at the Jonah Field, using high resolution aerial imagery, converted the maps to a binary (disturbed, not disturbed) layer, and used these two maps (Figure 1) to develop ‘before and after’ comparisons. Other input layers came from preexisting data sources. We applied the Biodiversity, Avoided Reservoir Sedimentation, and Carbon Sequestration models in InVEST to both the 1994 and 2007 disturbance layers, then calculated changes in the Ecosystem Service estimates from InVEST before and after intensive energy development.

Between 1994 and 2007, build out of the Jonah field resulted in 7,659.27 ha of disturbed habitat, mostly caused by new roads linking individual wells. Inter-Mountain Basins Big Sagebrush Shrubland decline by 3,861 ha and Inter-Mountain Basins Big Sagebrush Steppe, lost 1293.3 ha from development. We will present these changes in light of ecosystem services. As a tool, InVEST was relatively easy to understand and utilize. Given its recent development, we did encounter bugs in the biodiversity module but they were rapidly fixed by InVEST support staff. In addition, documentation for InVEST and its modules is still underway so some modules required considerable trial and error, posts to a user forum, and direct communication with InVEST programmers before completing successful model runs.