COPYRIGHT T. WILLIAMS
Figure 1. This view of the North Fork Bigwash Abyss comprises the Limber-Bristlecone Pine and Aspen–Mixed Conifer biophysical settings in the mid- to late succession stage. These vegetation classes are common in the southern half of the park. Both settings represent moderate departures from ecological reference conditions. Our analyses indicate the Aspen–Mixed Conifer vegetation class would benefi t from treatments to thin the conifer component.
The fundamental purpose of the National Park Service is to maintain, conserve, and restore park resources and the processes that sustain them, to the greatest extent practicable, to a condition minimally influenced by human actions, and to provide for visitor enjoyment of the same. Great Basin National Park was established to preserve unimpaired a representative segment of the Great Basin (described below). The park is to be managed so as to maintain the greatest degree of biological diversity and ecosystem integrity.
A century of fire exclusion combined with livestock grazing, nonnative plant species invasion, and stream diversions has resulted in large-scale conversion of many native vegetative ecosystems across the Great Basin and in the national park (Blackburn and Tueller 1970; Pyne 2004). Although livestock grazing permits were progressively retired and most water diversions were eliminated and restored since the park’s creation in 1986, nonnative annual grass invasion persists at lower elevations, whereas fire-sensitive conifers dominate in sagebrush shrublands and aspen forests as a legacy of fire exclusion. Occurrence of the majority of wildlife classified as species of management concern relates to habitat loss and degradation by conifer encroachment historically caused by fire exclusion, altered flows from former water diversions, and livestock grazing. Maintenance, protection, and restoration of sagebrush, aspen, riparian, and ponderosa pine vegetation community types and their dependent wildlife populations are of high priority for park management (fig. 1, above, and fig. 2, below).
COPYRIGHT T. WILLIAMS
Figure 2. This aspen riparian vegetation represents the Montane Riparian biophysical setting and occurs in the park’s drainages with perennial streams. Typical dominant woody species are aspen, cottonwood, willows, white fir, and wood rose. Overall this system exhibits low ecological departure, but the analysis found numerous areas in the park with higher ecological departure values because of conifer encroachment.
Identification of desired future conditions, which can be difficult for parks to define, and scenario modeling to achieve them are important steps in implementing restoration actions. Desired future conditions may be based on enabling legislation but more often are derived from some conceptualization of “pre-Columbian” condition. This conceptualization is often biased and difficult to quantify at a landscape scale.
In 2005 natural resources staff mapped the Fire Regime Condition Class (FRCC) of all the park’s major vegetation types using existing data, soil surveys, and GIS (geographic information system) software. Fire Regime Condition Class is a categorical measure of ecological departure from the reference condition (Hann and Bunnell 2001). Our initial work quantified desired future conditions in conjunction with fuels planning, complied with federal fire management guidelines, and produced a science-based fire management plan.
At this time, The Nature Conservancy (TNC) approached the park to collaboratively achieve the following goals: (1) map more accurately the park’s vegetation based on field-interpreted high-resolution satellite imagery; (2) develop computer models of all major potential natural communities that would allow characterization of their reference conditions (i.e., the pre-European settlement condition of the landscape); (3) evaluate current and projected future departure from reference conditions, including FRCC; and (4) simulate cost-effective management scenarios that would reduce future departure from reference conditions. We highlight mapping and management results from this collaborative effort.
Provencher, L., T. Anderson, G. Low, B. Hamilton, T. Williams, and B. Roberts. 2013. Landscape conservation forecasting™ for Great Basin National Park. Park Science 30(1):56–67.
Available at http://www.nature.nps.gov/ParkScience/archive/PDF/Article_PDFs/ParkScience30(1)Summer2013_56-67_Provencher_et_al_3652.pdf.