1. 1. Presence of cheatgrass (Bromus tectorum) on perennial grass ranges Use of perennial grass grazing systems on ranges where cheatgrass is already entrenched Grazing reductions since the early 1980s More fire, frequency and extent
2. 2. 0 2,000,000 4,000,000 6,000,000 8,000,000 10,000,000 12,000,000 0 50,000 100,000 150,000 200,000 250,000 300,000 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 acresburned #offires year fires acres National Interagency Fire Center data
3. 3. 1900 20001950 35 25 15 05 MillionsofAUMs Trends in Grazing on Federal Grazing Lands ------------Year--------------
4. 4. 1900 20001950 ------------Year-------------- Longer, hotter, drier summers
5. 5. Surgery applied at the wrong time, in the wrong place, with the wrong intensity, and the wrong duration becomes a bad thing. Grazing applied at the correct time, intensity, and duration can be an amazing tool to mitigate ecological challenges.
6. 6. CHEATGRASS RANGELAND
7. 7. CHEATGRASS RANGELAND
8. 8. Grazing Grazing Affects Fire Behavior Perimeter or Extent Patchiness Intensity Flame Length Rate of Spread Fire/Fuel
9. 9. Fire Modeling Simulated grazing effects on fire behavior while incrementally reducing herbaceous fuel loading and holding other fuel and environmental factors constant. Launchbaugh et al. 2008 Grazing Can Affect Fire Behavior
10. 10. Sagebrush Steppe(GS1) 10% Dead Fuel Moisture >15 10 15 5 0 Midflame Wind Speed (upslope) miles/hour >15 10 15 5 0 Fire Behavior Direct control of fire difficult when fireline intensity >100 BTUs or flame length > 4 ft.
11. 11. 12% Dead Fuel Moisture 10 >10 5 0 Midflame Wind Speed (upslope) miles/hour 10 >10 5 0 Sagebrush Steppe(GS1) Fire Behavior
12. 12. Grazing Affects Fuel Loads Accumulation of biomass & litter Distribution of litter around perennial grass crowns Ungrazed Grazed Photos: Kirk Davies
13. 13. Grazing affects Fuel Loads Mike Pellant
14. 14. Grazing & Fuels What does science tell us? 2) Grazing can reduce fuels 3) Grazing will not stop fires under very hot & dry conditions. 4) Grazing can reduce cheatgrass & grazing can increase cheatgrass 5) Grazing can reduce fire intensity & change fire behavior more research needed. 1) Grazing can change plant & fuel composition long term
15. 15. Exclosures Water Lick Tanks TS Ranch Dunphy, NV Mack Farm Pasture ~ 6000 acres 60 % go back farmland 40 % greasewood/ cheatgrass 800 cows Oct. 8 to Nov. 15 (38 days) N0.5 miles
16. 16. Current research is indicating that in areas where cheatgrass is already entrenched, the amount of carryover aboveground biomass will dictate the dominance of cheatgrass. Trowbridge, W., Albright, T., Ferguson, S., Li, J., Perryman, B. L., Nowak, R. S. 2013. Explaining patterns of species dominance in the shrub steppe systems of the Junggar Basin (China) and Great Basin (USA). Journal of Arid Lands, 5:415-427. doi: 10.1007/s40333-013-0174-y jal.xjegi.com; www.springer.com/40333 Schmelzer, L., B. Perryman, B. Bruce, B. Schultz, K. McAdoo, G. McCuin, S. Swanson, J. Wilker, and K. Conley. 2014. Case Study: Reducing cheatgrass (Bromus tectorum L.) fuel loads using fall cattle grazing. Professional Animal Scientist, 30:270-278.
17. 17. Questions?