Great Basin National Park: An ecological landscape analysis

Unnasch, Robert; Comer, Patrick; Braun, David

The Great Basin faces increasing demand for development of energy resources and energy transmission infrastructure--as does most of the arid western U.S. Energy and other development-related concerns for National Parks are the facilities themselves, utility rights of way, and associated roads, and emissions from the facilities. Although these potential sources of stress lie outside of parks, unit managers need to assess the potential for impacts to Park resources and values. It is important though, that managers identify specific concerns to improve the chances of mitigating problems before they occur. This report assesses the sensitivity of ecological resources within the Great Basin National Park (GRBA) to energy development on lands surrounding the Park. Specifically, it tests the value of regional ecological data as applied through the Ecological Integrity Assessment Framework to distinguish the degree of potential threats to specific park resources. After scoping the geographic scale and related focal resources for the assessment in our 2012 analysis, we identified fourteen focal ecological resources of GRBA that could be sensitive to the impacts of energy development within the study area. The focal resources include seven large-scale ecosystem types, wind erodible soils, three sensitive species assemblages, (migratory waterfowl / shorebirds, tree-roosting bats, and, cave-roosting/riparian-foraging bats), and four individual species for which both the Park and the surrounding landscape provide important habitat, including movement corridors. We then developed or adapted a conceptual ecological model for each focal resource, to identify key ecological attributes and their indicators and document current understanding of the effects of stressors on the ecological integrity of the resource. The conceptual models identified eighteen indicators or indices – composites of multiple indicators – for which data were available for evaluation among the several key ecological attributes. Eight indicators/indices generated values with little or no variation within the study area, while ten presented sufficient variation to support quantitative analysis. These are: • Landscape Condition Index • Fire Regime Departure Index • Riparian Corridor Continuity Index • Invasive Annual Grasses Index • Groundwater Use • Surface Water Use • Hydrologic Condition Index • Mercury Deposition • Nitrate Deposition • Water Quality Index We analyzed the potential impact of energy development on each resource in two ways, in terms of: (1) the overlap between the areas of energy development and the spatial distribution of each focal ecological resource; and (2) the possible impacts of energy development on the ecological integrity of each focal resource across the entire study area. The assessment results identify two ways in which the ecological resources of Great Basin National Park may be affected by energy development on lands surrounding the Park. First, significant percentages of the current spatial distribution of several focal ecological resources fall within the 2012 footprint of energy development, and even larger percentages within the footprint forecasted for 2025. The inter mountain basins big sagebrush shrubland, inter-mountain basins greasewood flat, Great Basin foothill and lower montane riparian woodland and shrubland/stream, and inter-mountain basins wash system types; the migratory waterfowl & shorebird assemblage; the cave-roosting, riparian-foraging bat assemblage; and the golden eagle and pygmy rabbit are forecasted to experience the greatest increases in the percentages of their areas included within the footprint of energy development. Wind erodible soils, greater sage grouse lek sites, and bighorn sheep movement corridors may also be highly vulnerable, with large percentages of their areas falling within the footprint of energy development even in 2012.

Great Basin National Park: An ecological landscape analysis

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