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Developing a Dataset to Assess Ecosystem Services in the Midwest, United States
Citation:
MEHAFFEY, M. H., R. Van Remortel, E. R. SMITH, AND R. J. BRUINS. Developing a Dataset to Assess Ecosystem Services in the Midwest, United States. International Journal of Geographical Information Systems. Taylor & Francis, Inc., Philadelphia, PA, 25(4):681-695, (2011).
Impact/Purpose:
There is an urgent need to mature our understanding of the services provided by the ecosystems of the Midwestern United States. Ecosystem services have been variously defined as the benefits people obtain from ecosystems (Millennium Ecosystem Assessment, 2005) and aspects of ecosystems utilized to produce human well-being (Fisher et al., 2009), and they include, for example, the provision of clean air, clean water, flood control and nature-based recreation opportunities, as well as the production of food, fuel and fiber. The Midwest is responsible for a significant proportion of the world’s grain production. For example, in 2005, approximately 23 percent of the world’s maize, soybeans and wheat originated from the 12-state area outlined in Figure 1. However, the Midwest also exports less desirable products in tandem with grain. Nutrient runoff from Midwest farmlands contributes to seasonal hypoxia in the Gulf of Mexico (Alexander et al., 2008) and eutrophication of local streams and lakes, while commonly used herbicides are frequently detected in shallow groundwater (Gilliom and Hamilton, 2006). Farming within the rich floodplains of the Midwest has modified the drainage and water-holding capacity of these soils resulting in increased heights and frequencies of floods in the Upper Mississippi River basin (Pinter et al. 2006). Water quality and quantity problems are expected to be exacerbated as rising grain prices spur a switch to monoculture cropping, expansion of corn production into lands with competing crops (i.e. cotton and wheat) and potential conversion of Conservation Reserve Program (CRP) lands back to field crops (Westcott, 2007). The pressure to increase corn production is also likely to affect already-marginalized wildlife species reducing populations, thereby decreasing important ecosystem services such as the existence of native biodiversity, wildlife viewing opportunities and recreational use.
Description:
There is an urgent need in the science community to enhance our understanding of the services provided by the ecosystems of the Midwestern United States. The following paper describes a method for creating an enhanced spatially explicit land cover for the Midwest. We constructed a detailed classification of the agriculture practices and expanded the range of detail on the natural cover types occurring across the Midwest using data from multiple sources. The 2001 National Land Cover Dataset provided our base grid to which we augmented the single 'cultivated crops' land cover class into multiple crop rotation types using USDA's Cropland Data Layer and expanded the natural cover classes using the LANDFIRE program's existing vegetation type coverage. Tillage and management practices for specific crops came from the Agricultural Resource Management Survey. Crop-specific yield estimates were added from the Natural Resource Conservation Service's Soil Survey Geographic Database (SSURGO) and from National Agricultural Statistics Service county level data. The final 30 m grid data was linked to the land cover classification and tabular information on management. Capturing the land cover and land management information at the grid scale allows for aggregation or modeling of the data at different scales depending on the needs of the user. The greater detail will also allow for an assessment of location and connectivity effects on ecosystem functions. The final product will be used for evaluation of a suite of ecosystem services and will serve as a cornerstone for determining where increased corn production could take place in order to satisfy future 2022 ethanol fuel mandates.