Abstract
GIS (Geographic Information Systems) and GPS (Global Positioning Systems) technologies have become important tools for assessing and updating the environmental status of rangeland allotments on the HumboldtToiyabe National Forest. Natural resource professionals use USGS Digital Elevation Models (DEMs), vegetative information and watershed overlays to initially estimate carrying capacities for permitted domestic livestock based on limiting topography and distance from water. Layers showing critical wildlife and fisheries habitats are also available. The GIS maps derived with these data layers help identify areas of overlapping use, assist in establishing key monitoring sites and prescribe recommendations on acceptable livestock management practices. Field verification of natural and manmade features associated with rangeland allotments is completed primarily with the assistance of GPS. The gathered field data can then be used to correct and refine the GIS data base for the forest. This process was completed on the Whiterock Cattle and Horse Allotment in the Independence Range in NE Nevada to assess the effectiveness of a 10-year management plan completed in 1985. The ability of computer specialists and field professionals to work together creates a 2tiered benefit demonstrated by the Whiterock review: better information to conduct environmental analyses and a more accurate GIS data base to draw from for future needs.
GIS Applications to Assess Rangeland Allotments
The Whiterock C and H allotment incorporates approximately 17,300 acres of rugged Great Basin country adjacent to the Idaho/Nevada border on the HumboldtToiyabe National Forest (Figure 1).
It is a landscape dominated by sagebrush, bunch grass communities with inclusions of aspen and subalpine fir (Figure 2).
In 1985 an Environmental Assessment (EA) and subsequent Allotment Management Plan (AMP) were completed and implemented. GIS played a crucial role in this analysis. By GIS the reference is to the encompassing environment of computer hardware, software, data and personnel assigned the responsibility of handling geographically referenced information (Understanding GIS: The ArcInfo Method, ERSI Inc., 1990). Tiering back to land management objectives within the AMP, a review was conducted in 1995, first looking at the rangeland resources captured in the GIS data layers, then verifying and monitoring the information depicted on maps out on the ground.
Basic Information Using What's on Hand
Digital Elevation Models from the U.S. Geological Survey, stream locations, vegetation types, land ownership designations and allotment boundaries are the primary layers used for this type of analysis. These provide basic information on parameters for assessing two important land use attributes, grazing suitability and overall forage productivity. Suitable acres are derived looking at two geographical characteristics: percent slope < 30% (for cattle) and distance from a perennial water source ( less than one mile). Productivity figures were calculated using the suitability derivation, then incorporating more specific data from the vegetation layer. These included: plant community type, their seral state along an ecological pathway and production measurements in lbs/acre by dry weight. Carrying capacities for available forage for cattle were then calculated through the Statistics program using a forage requirement of 1040 lbs./ Animal Month (for a cow/calf pair) and an average allowable use factor for forage consumption by weight of 40% over all community types.
This information was available due to a contract completed in 1989 for the Cumulative Effects Analysis (CEA) on the Independence Range, where the Whiterock allotment is located (CEA Project, Independence Range, Mountain City District: A Partnership, 1991). This comprehensive analysis was initiated in 1989 to geographically review and quantify the impacts of increasing mineral exploration and extraction activities in the area. The contract provided for the collection of upland and riverine riparian plant community information using ECODATA, a standardized system used by Region 1 of the Forest Service for describing basic ecosystem information. The method provides for flexibility not only in the type of information collected, but in the acceptable information ECODATA can assimilate from other software applications, both from sources inside and outside the agency. For the original purpose of the CEA seven years ago, data collection centered on species composition, vegetation structure and production, soil descriptions and land use histories. These surveys were completed on 5 acre plots throughout the Independence Range. By accessing this data now, a critical objective of the CEA Project was realized, ie. to provide accurate resource information for future projects with a minimum amount of field replication. These plots provided necessary background information on the Whiterock allotment to initate this review and revisit sites, information that otherwise would have required extensive up-front field time. The availability of this data allowed the rangeland specialist to target certain critical sites during the field season rather than playing hit and miss over the landscape.
Putting It Together
The suitability map
and forage productivity map provide baseline data on requirements for domestic livestock on rangeland allotments. In the multiple use spectrum, other resources share the ground and have their own requirements. Based on key issues identified when an EA is written, other resource information can be pulled up to identify spacial relationships with permitted livestock grazing. In congruence with the vegetational information, GIS layers outline locations for deer fawning habitat and summer range, and sage grouse/blue grouse strutting and brooding habitats. For the Whiterock area the issues centered around the ecological status of critical riparian vegetation types including mesic meadows, woody riparian types and aspen stands. Many of these areas are the same sites critical for both upland game bird needs and mule deer summer habitat requirements.
Using GPS
With maps in hand, the rangeland specialist can outline the areas to visit over the summer. This is where the GPS applications come in. Over the past three years GPS has been used to locate many different natural and manmade features on the forest. Sensitive plant populations, raptor nesting sites, archaeological sites and permanent monitoring points are now part of the GIS data base available to resource professionals. More recently the GPS units are used to verify vegetation mapping and accurately find rangeland improvements: fences, pipelines and water troughs and pit tanks included within defined allotments.
This information is then used to update permit administration maps associated with term grazing permits. All of these GPS applications serve to correct and clarify the different data layers within the GIS. For rangeland allotment applications this has primarily meant corrections in manmade features: allotment boundaries and range improvement locations. By providing accurate geographical reference points from which to start and actual locations of designated features, GPS helps incoming range specialists efficiently locate key vegetative areas and range improvements for allotment monitoring and grazing permit administration.
Assimilation: GIS and Reality
The increased involvement of field-going resource professionals with GIS has changed how rangeland analysis occurs on National Forest System lands in NE Nevada. Familiarity, if not total proficiency, with GIS allows range specialists to insure what is diagramed on the screen reflects the reality of the landscape. This was the case on the Whiterock allotment. After several field reviews, the range specialist noticed some critical meadow complexes had not been delineated in the GIS vegetation layers. These were sites designated in the EA and AMP as key areas for determining trends in ecological status. In another instance the interpretation of Cartographic Feature Files (CFFs) relating to the allotment boundary was in error, offsetting the perrenial streams from their actual location. Once recognized, corrections were easily made in the office. Only through this feedback interaction between the GIS information and the field data could the best available information be assimilated for the final evaluation. The collaborations of professional skills continually refine the Forests GIS information as new projects and environmental reviews begin. Cumulatively this will make large planning efforts, such as the upcoming Forest Plan Revision, scheduled to begin in 1997, less daunting.
Partnerships = More Accurate Data = Better Decisions
It is difficult to schedule time to work with GIS these days in the NE Nevada Forest Service office; the calendar is booked. Most range specialists are teaming with computer specialists to correct and clarify the data layers comprising the rangeland allotments they are responsible for. GIS and GPS technologies have become important tools, but they cannot stand alone. Continual review and verification of the information by resource professionals on the ground are critical to insure the most accurate information. The Whiterock allotment review is the one of many efforts underway to marry the expertise of different disciplines to complete analysis objectives. The benefits of this interdisciplinary relationship parallel and complement the other: increased use and comfort with GIS applications for rangeland management, better efficiency in collecting background information at the start of an analysis and more accurate data on which to base future land use allocations and management decisions on the National Forests, in Nevada and elsewhere.
Acknowledgments
This paper and the cooperative process it describes would not have been possible without the support of the Leadership Team of the Humboldt-Toiyabe National Forest, specifically the NE Nevada Ecosystem representatives: Assistant Forest Supervisor Ben Siminoe, District Ranger Scott Bell and Acting District Ranger Dave Aicher. Thanks to Renie Smith, Cathie Jean and Roger Johnson for their editing skills. Special appreciation to Tom Jeffers in the Elko office for allowing his space to be invaded while this paper was frenetically put together. Also lastly, thanks to Timothy Brogan for his help in getting this coded in HTML and FTP'd to this site.
References
Understanding GIS: The ArcInfo Method. Self Study Work
book. 1990 . ERSI Inc., Redlands, California. pp. 1-2 to 1-3.
CEA Project: Independence Range, Mountain City Ranger District: A Partnership. 1991. USDA Forest Service, Region 4, Humboldt National Forest.
Author Information
N. Chrystine Olson
Rangeland Management Specialist
USDA-Forest Service, Humboldt-Toiyabe National Forest
2035 Last Chance Road
Elko, Nevada 89801
702-738-5171
702-778-0299
E-Mail - NA
Bonnie Whalen
Geographical Information Systems Specialist
USDA- Forest Service, Humboldt-Toiyabe National Forest
2035 Last Chance Road
Elko, Nevada 89801
702-738-5171
702-778-0299
E-Mail - NA