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Weed Impacts on People

Picture of ranchers on horses herding cattle

Ranching and Farming
The livestock industry is at the heart of many rural communities in the Great Basin. More and more, ranchers are relying on cheatgrass to provide forage for their livestock. However, the annual forage production of cheatgrass is highly variable. Years with more precipitation create a flush of cheatgrass growth. In drier years, forage productivity is minimal. Cheatgrass forage quality declines quickly as it matures, providing forage only a short time. The number of livestock supported during these boom and bust cycles varies. This is mirrored in livestock producer income.

Invasive weeds quite often replace more valuable forage. This is especially true for cattle. Leafy spurge and knapweeds have been shown to reduce grazing capacity by more than 50%. Some invasive weeds are poisonous to livestock. Halogen produces toxic oxalates that are especially poisonous to sheep.Picture of dryland farm fields When horses ingest too much Russian knapweed or yellow starthistle, it causes a fatal neurological disorder. Leafy spurge produces a milky sap that irritates the mouth and digestive tracts of cattle.

Weeds like Canada thistle, Russian thistle, whitetop, and cheatgrass reduce crop yields. These rangeland weeds put dry-land agriculture particularly at risk. In addition, hay and seed crops containing invasive weeds have limited market value due to the risk of weed spread.




Picture of a man fishing

Tourism and Recreation
Invasive weeds affect the Great Basin’s tourism industry. People wanting to hike, hunt, fish, ride, camp, or recreate in other ways look elsewhere when these opportunities are unavailable. Recreators don’t get their outdoor experiences, and the money they don’t spend on supplies, licenses, guiding services, etc. is lost to the Great Basin economy.

Picture of a rider on a mountain bike

Cheatgrass-fueled fires destroy signs, impact trails and camping areas, and mar the Great Basin scenery. Off-highway vehicle use in burned areas is often temporarily discontinued to prevent erosion and discourage weed spread. Because of invasive weeds, streamside habitats are altered and erosion can increase, influencing fishing opportunities. Lost wildlife habitat reduces populations, making animals sparse for viewing or hunting. Invasive weeds with sharp thorns or annoying burrs can make camping areas or trails unpleasant to visit.


Group getting ready to spray herbicide with ATV's

Control and Restoration
Invasive weeds cause more economic loss on rangelands than all other pests combined. In the Great Basin, cheatgrass has caused fire frequency and magnitude to escalate, increasing fire fighting costs. More fences, barns, and houses have been burned or threatened. Weed control efforts have risen, meaning more money spent on research, herbicides, fuel, education…the list is extensive. Costly revegetation projects try to curtail weed invasion and restore desirable plant communities. Unfortunately, there seems to be no end in sight.

Images:
-Ranching: USDA-NRCS.
-Dry farming: Southwest Regional Gap Analysis Project. Field site database. (http://earth.gis.usu.edu/swgap/trainingsites.html, 26 September 2006).
-Fishing: Curtis Henderson.
-Biking: Public domain.
-Control efforts: Public domain.

Text references:
-Entwistle, P.G., A.M. DeBolt, J.H. Kaltenecker, and K. Steenhof, compilers. 2000. Proceedings: Sagebrush Steppe Ecosystems Symposium. Bureau of Land Management Publication No. BLM/ID/PT-001001+1150,Boise, Idaho, USA.
-Pellant,M. 1996. Cheatgrass: the invader that won the west. Unpublished report. On file with: U.S. Department of Agriculture, Forest Service; U.S. Department of Interior, Bureau of Land Management; Interior Columbia Basin Ecosystem Management Project, 112 E. Poplar, Walla Walla, A 99362.