Rachel Frost, Jeff Mosley, Tracy Mosley, and Brent Roeder

Transcription

1 Alternative Grazing Strategies for Industry Diversification and Rangeland Improvement Rachel Frost, Jeff Mosley, Tracy Mosley, and Brent Roeder

2 State of the Range Rangelands account for < 40% of the world s land area Most degraded land type Damage generally attributed to livestock grazing Less land available for livestock production: Development Invasive Species Wildlife Conflicts World Population Growth

3 Challenge Find ways to intensify production on remaining acres and simultaneously improve land health. Pappanastasis (2009) asserts that..the solution is not to achieve exclusion of livestock grazing from restoration projects but to adapt grazing management to help restore degraded grazing lands.

4 Power in Integration Mechanical Fire Grazing Cultural Biological control Chemical Integration

5 Power in Integration Grazing Mechanical Fire Cultural Chemical Integrated systems More complete achievement of objectives More rapid than single method More economical vegetation management More readily embraced by land managers Biocontrol

6 Grazing and Fire Grazing: Manipulate fuel loads to control/modify fire intensity Create firelines for prescribed burns Control seed production prior to / or following fire Fire: Top kill tall brush Reduce seeds in litter and soil Release nutrients Firebreak outside Kuna, ID (photo by John Sullivan, ID BLM) Photo TAMU Vernon

7 Grazing and fire Cheatgrass Targeted livestock grazing: Diamond et al Early spring (boot stage) Reduce seed production and biomass prior to fire Fire: Fall - Removes litter and associated seeds Reduces safe sites for seeds to germinate Graze following spring - Control new plants Photo by USFS

8 Browsing and fire Juniper Targeted livestock grazing: Create firelines for Rx burn Fire: Fire top-kills juniper Goat browsing: Control re-sprouts and seedlings Genetic selection for ability to resist juniper toxins Photo: Butch Taylor, TAMU

9 Grazing and herbicides Herbicide: Age class Size of infestation Plant community composition Grazing: Age class Plant community structure Expand treatment window Reduce seed rain Reduce the number of plants or acres requiring treatment

10 Grazing and herbicides Spotted knapweed Herbicide then sheep (Sheley et al. 2004) Low residual herbicide used to: Move plant community to juvenile plants More palatable/preferred by sheep More reduction in density than either method alone Leafy Spurge Goats then herbicide Lym et al Prevent seed rain until herbicide can be applied Stress root system for better herbicide kill Control lasted longer than either method alone

11 Grazing and Mechanical Control Chaining, Dozing, Shearing, Mowing Knock down tall, decadent vegetation Improve accessibility for livestock Livestock Control Regrowth Shrubs Re-growth less toxic, (Campbell et al. 2006) Herbaceous Re-growth more palatable, nutritious Photo: Rachel Frost Photo: Butch Taylor, TAMU

12 Grazing and Cultural Control Seeding: Removing competitive vegetation/mulch; trampling seed, soil contact (Havstad 1994) Fertilizer: grazing reduces weed, fertilizer increases grass (Kohn & Cuthbertson 1975) Grazing Management: Multi-species grazing, seasonal concentration (Henderson et al. 2012; Thrift et al. 2008; Frost et al. 2012)

13 Targeted Grazing and Insect Biological Control Biocontrol alone effective in only 30% of cases (McFadyen 1998) Potential for synergistic effects: Cumulative stress from herbivory Concentration of seedhead feeding insects Concerns: Livestock interfering with population growth and stability Biological controls not designed for eradication

14 Integration of Targeted Grazing with Insect Biocontrol Leafy spurge: Increased control when targeted grazing used in conjunction with flea beetles (Jacobs et al. 2006) Yellow starthistle: Grazing by sheep or cattle did not impact the effect of seed head feeding insects on seeds of yellow starthistle (Wallace et al. 2008)

15 VIABLE SEED PRODUCTION OF SPOTTED KNAPWEED 700 Knapweed Viable Seed Production / m # per meter July Grazed Paddocks August Grazed Paddocks Insects Only

16 SEEDLING NUMBERS PER METER 2 # per meter Spotted Knapweed Seedlings July Grazed Paddocks August Grazed Paddocks Insects Only a a a After 2 Years of Grazing b 35 b 86 c After 3 Years Grazing

17 Results Summary Grazing does not reduce the Larinus or Cyphocleonus populations the following year. Sheep grazing and biological controls together reduced seed production 99% more than biological control alone. Grazed paddocks had 5 times fewer seedlings than paddocks that were not grazed by sheep.

18 Power in Integration Grazing Mechanical Fire Cultural Chemical Integrated systems More complete achievement of objectives More rapid than single method More economical vegetation management More readily embraced by land managers Biocontrol

19 ALTERNATIVE GRAZING STRATEGIES FOR INDUSTRY DIVERSIFICATION AND RANGELAND IMPROVEMENT