This project will utilize specific treatments on southwestern Wyoming salt-desert shrublands that have been invaded by halogeton to improve habitat conditions. Treatments to improve habitat conditions will include a variety of soil preparation techniques such as traditional till and minimal till and seeding techniques including drilling and broadcast seeding. Monitoring of these areas will occur post treatment to determine the most effective methods for restoration. Treatment and monitoring of treatments will occur for at least two years as part of this proposal.
Background: Western states have experienced overwhelming anthropogenic disturbances in recent decades. This has resulted in the introduction of numerous non-native plant species and the loss of native vegetation. The impact severity varies greatly depending upon the introduced species' ability to establish itself, out-compete native plants, and alter the ecosystem. Non-native species which have this ability are often designated by states as noxious weeds.
One species of particular concern in Wyoming and other western states is halogeton (halogeton glomeratus). It is listed on numerous noxious weed lists including Carbon, Converse, and Natrona's Noxious Weed List (see 2008 Declared List of Weeds and Pests for Wyoming) and is found in the Wyoming Weed and Pest Council Weed Handbook (series 1-55). In addition, halogeton is of particular concern in southwest Wyoming for the following reasons: 1) it is ideally adapted to the alkaline soils and semi-arid environment of high-desert winter livestock ranges in the area; and 2) monitoring shows halogeton is invading and displacing numerous saline and xeric sites in southwest Wyoming. Of specific concern to this proposal is the 3,000 acres of Gardner saltbush (Atriplex gardner) that have been displaced by halogeton over the past 10-20 years within the Flaming Gorge Ranger District, and Flaming Gorge National Recreation Area. This area provides a multitude of benefits to a wide variety of users in the area including recreationists, ranchers, wildlife, and other users. The combined uses bring many economic and non-economic benefits to local communities and the impact of the introduced species to these activities is outlined below:
Recreation: The loss of thousands of acres to halogeton has and continues to result in reduced recreational opportunities and aesthetic benefits of the area. As recreational opportunities and aesthetic benefits are reduced, economic benefits to local communities as a result of recreational visits will be reduced.
Domestic Livestock Grazing/Local Economies: The affected area is part of the Cedar Mountain Allotment where summer grazing by cattle and winter grazing by sheep occurs. As recent as 2008, 1,400 to 1,500 AUMs were permitted for livestock grazing in the area of concern (see attached Map including the Double Bridge and Holme's Crossing units of the Cedar Mtn. Allotment). From a Forest Service perspective only, the economic value of these AUMs to the local economy is $123,844 - $132,690 annually. From a ranch production perspective, the economic value of these AUMS to the local economy is $173,390 - $185,775 annually. From a ranch viability perspective, the economic value of these AUMS to the local economy is $377,734 - $404,715 annually (see economic report for Bridger Teton National Forest produced by Taylor et. al., 2008). However, because the forage base of the area has been reduced due to displacement by halogeton the number of AUMs currently authorized in the NRA has been reduced by 450-500 AUMs. This has resulted in an economic loss of $39,807 - $44,230 (Forest Service perspective), $55,732 - $61,925 (ranch production perspective), or $121,414 - $134,905 (ranch viability perspective) annually (Taylor et. al., 2008). As halogeton continues to displace plant communities in this allotment, similar reductions can be expected. In addition to the reductions in grazing, halogeton also causes livestock losses via its toxic properties (it accumulates oxalates which are fatal to domestic stock, especially sheep). Due to the continued expansion of halogeton in this area, losses of livestock via halogeton are expected to increase.
The Forest Service perspective assumes that the only affect on the ranching operation from Forest Service grazing is the direct production associated with the AUMs. The ranch production perspective considers the change in total ranch production resulting from the change in grazing assuming that the ranch still remains in operation. The ranch viability perspective considers the change in total ranch production resulting from the change in grazing assuming that the ranch ceases operation without Forest Service grazing. The perspectives that is the most correct to consider depends on a number of factors --including the individual ranch’s level of dependency on Forest Service grazing, the magnitude of the proposed change in grazing, the financial solvency of the ranch, the availability of alternative sources of forage, and the desire of the rancher to remain in ranching. For small changes the Forest Service Grazing only perspective may be the most appropriate. For larger changes where the ranching operation might still stay in operation, the Ranch Production Perspective may be the most appropriate. For larger changes where the economic viability of the ranching operation is uncertain, the Ranch Viability Perspective may be the most appropriate.
Wildlife including small mammals: Crucial/critical range is present within the project area for antelope and deer. In addition, crucial/critical range for elk is present on the east side of the reservoir adjacent to the project area. This area consists of the same plant community types located within the project area and has started to see invasion of halogeton of halogeton and displacement of salt-desert shrubs (displacement is not as far along as the project area). The displacement of perennial species in the project area and other areas in Southwest Wyoming by halogeton and other invasive species has degraded habitat conditions and diminished forage for these and other wildlife species, including small mammals and birds.
Watershed Health: Watershed health and integrity has been reduced as native perennial plants are being replaced by halogeton, an annual warm-season plant. Areas displaced are now more susceptible to wind and water erosion. Of particular concern is late spring and early summer, when areas are almost completely devoid of vegetation and high winds are common.
Other: Salt-desert shrublands are common throughout southwest Wyoming. Increased recreational pressure and energy extraction is expected to continue to increase in these areas. Increased activities are expected to facilitate halogeton invasion and displacement of salt-desert shrublands. The information obtained through completion of the project treatments and monitoring data will be useful for land managers and others in southwest Wyoming, the entire state of Wyoming, and other western states for the following reasons:
1) The project treatments and associated monitoring of areas will provide a better understanding of the process of displacement; the activities that will need to occur to prevent or minimize displacement; and the possible actions that may be taken to restore areas displaced by halogeton.
2) Existing data now indicates a legitimate concern exists over the potential displacement of other communities by halogeton including winterfat (krasheninikovia lanata), mixed desert shrub, and Indian ricegrass (Oryzopsis hymenoides) communities.
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