2012 Annual Report 1a.Objectives (from AD-416): Human impacts on the environment are altering species composition in many of the nation's national parks. One such impact is the increase in invasive plant species which are quickly over-running many of the native plant species. One such invasive species is Japanese stiltgrass (Microstegium vineum). The objective of the current research is to quantify human impacts, particularly nitrogen deposition, carbon dioxide and light on the ability of this species to grow and propagate. 1b.Approach (from AD-416): Working with the National Park Service's Center for Urban Ecology, we will obtain local seed from stiltgrass populations and determine growth and see production utilizing a range of nitrogen deposition rates and carbon dioxide concentrations under glasshouse and growth chamber conditions Data will be utilized in a multiple regression model in order to ascertain whether human induced changes in macroclimate near the D.C. area will contribute to the peniciousness of this invasive species. 3.Progress Report: Meteorological and edaphic data are currently being collected and analyzed along a roadside transect in Catoctin National Park. In addition, a second study was initiated with the National Park Service to establish exclusion fencing around existing microstegium stands at the Catoctin transect. The goal of the exclusion study was to determine whether, in the absence of herbivory, native plant species could out compete the invasive microstegium.