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Integrating Weed Control and Restoration

Integrating Weed Control and Restoration. The problem: Cheatgrass ( Bromus tectorum ) invasion in Great Basin rangelands. Unburned. Burned. Frequency. Young & Evans (1978). Why is cheatgrass so successful?. Prolific seed production. High competitive ability. Changes disturbance regime.

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Integrating Weed Control and Restoration

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  1. Integrating Weed Control and Restoration

  2. The problem:Cheatgrass (Bromus tectorum) invasion in Great Basin rangelands

  3. Unburned Burned Frequency Young & Evans (1978) Why is cheatgrass so successful? • Prolific seed production • High competitive ability

  4. Changes disturbance regime

  5. Solution X

  6. Robert Nowak Hudson Glimp Nancy Markee Barry Perryman Gene Schupp Chris Call Paul Doescher John Tanaka Jeanne Chambers Robin Tausch Integrating Weed Control and Restoration: Collaborators David Pyke Robert Blank Tom Jones Dan Ogle Loren St. John Mike Pellant

  7. Experiment 1: A transition stage approach • Plant materials for transition stage • Bluebunch wheatgrass – Anatone, Goldar, P-7, P-12 • Snake River wheatgrass – Secar, SERDP • *Basin wildrye – Magnar, Trailhead • Sandberg bluegrass – Hanford, High Plains, • Mountain Home, Sherman • Thickspike wheatgrass – Bannock, Critana • Squirreltail – Sand Hollow, Shaniko Plateau • *Western yarrow – Eagle, Great Northern • Scarlet globemallow • Siberian wheatgrass – Vavilov • Crested wheatgrass – CD-II • Annual grass hybrids – Mountain rye, • Pioneer, Regreen, Stani • * Note: replaced with winterfat, shadscale, four-wing saltbush, & • Rimrock indian ricegrass at Nevada’s Izzenhood Ranch study site

  8. 390' 50' Herbicide application 50' 50' 50' 410' Individual study plots with varietal seeding randomly assigned. Each plot has 10 rows with 1‘ row spacing. 20' 10' 70' 10' 10' 120' Experiment 1: A transition stage approach

  9. Experiment 1: A transition stage approach • Effects of herbicide treatments: • Reduces cheatgrass

  10. Experiment 1: A transition stage approach • Effects of herbicide treatments: • Reduces cheatgrass, but other species increase

  11. Experiment 1: A transition stage approach • Effects of herbicide treatments: • Reduces cheatgrass, but other species increase • Variable for seeded species

  12. Experiment 1: A transition stage approach • Success of seeded species – Nevada

  13. Experiment 1: A transition stage approach • Success of seeded species– Nevada

  14. Experiment 1: A transition stage approach • Success of seeded species– Nevada

  15. Experiment 1: A transition stage approach • Success of seeded species – All sites • Best performers (comparable to crested wheatgrass): • Anatone & P-12 bluebunch wheatgrass • SERDP & Secar Snake River wheatgrass • Critana thickspike wheatgrass • Sherman sandberg bluegrass

  16. Experiment 2: A plant functional type approach • Cheatgrass inhibited by low soil nitrogen, • but natives are tolerant of low nitrogen

  17. Experiment 2: A plant functional type approach • Cheatgrass inhibited by low soil nitrogen, • but natives are tolerant of low nitrogen • Soil amendments to tie up nitrogen

  18. Experiment 2: A plant functional type approach • Cheatgrass inhibited by low soil nitrogen, • but natives are tolerant of low nitrogen • Soil amendments to tie up nitrogen (sucrose) • Mix of natives to deplete resources • sagebrush – evergreen; extensive rooting • High Plains bluegrass – earliest; shallowest • Sand Hollow squirreltail – early; shallow • Anatone bluebunch wheatgrass – mid; extensive • Great Northern yarrow – mid; surface root mat • scarlet globemallow – early; extensive

  19. 300' Herbicide application Sugar application No sugar 15 m 350' 15 m 15 m Individual study plots with seeding treatments randomly assigned 15 m 1.5 m 2.5 m 15.5 m 2 m 2 m 2 m 2 m 23 m Experiment 2: A plant functional type approach

  20. Specific questions • Did sucrose reduce soil N? • Did the ‘target species’ benefit? • Did sucrose facilitate establishment? • Did cheatgrass reduce native recruitment? • Was cheatgrass adversely affected? • Did the 6-species mix reduce cheatgrass? • Was cheatgrass seed output, biomass, or density reduced?

  21. P=0.02 P<0.001 • Did sucrose reduce soil N ? Oct 2003 - Jan 2004 Jan 2004 - March 2004 Micrograms NO3 per day

  22. Experiment 2: A plant functional type approach • Success of seeded species:

  23. 2.2 Did cheatgrass reduce native recruitment ? • Target species density second season (NV): • High precip site: species differ (p<0.001) • Low precip site: species differ (p<0.001) • & BRTE by sucrose interaction (p = 0.003)

  24. 3.1 Did the 6 species mix reduce cheatgrass? sugar: p = 0.02 species: p = 0.001 species: p= 0.01

  25. 3.2 Was cheatgrass seed output, biomass or density reduced? P = 0.005 P = 0.0004

  26. Experiment 2: A plant functional type approach • Effects of sugar treatments: • Reduces cheatgrass biomass and seed production • Consistent effect among all sites

  27. Conclusions • Did sucrose reduce soil N? YES • How well did ‘target species’ establish? • Did sucrose facilitate establishment? No • Did cheatgrass alter native recruitment? yes • Was cheatgrass adversely affected? • Did the 6-species mix reduce cheatgrass? • NO • Was cheatgrass seed output, biomass, or density reduced? Sucrose YES, species mix NO; effect short-lived

  28. Experiment 3: Large-scale restoration trials

  29. Experiment 3 Overview • Application of successful restoration techniques from Experiments 1 and 2 • Transition community vs. Native mix • Restoration treatments targeted at: • reduce cheatgrass seedbank • reduce available soil N • Use ecological principles from first 2 experiments on large, management-scale plots

  30. Bedell Flats • BLM allotment – primary use was grazing • Secondary uses include off-road vehicle use and target shooting • Burned in the summer of 2000 • Subsequently seeded by BLM • Thickspike wheatgrass • Crested wheatgrass • Western wheatgrass • Four-wing saltbrush • Ladak Alfalfa • Fenced in April 2005

  31. Objectives • Determine the relative success of restoration strategies to control cheatgrass competition and its prolific seed production. • Determine whether a transition community of competitive natives can be established more readily than a diverse community of different growth forms

  32. Transect 1, zero point Split-plot treatment polygons (170m x 340m) Northern Fenced Region 1b 1a 2a 2b BLM cultural survey area 3a 3b Treatment Control Seed-Burn Herbicide Unseeded Control Southern Fenced Region 4b 4a 5b 5a 6b 6a 7b 7a 8a 8b 9a 12b 9b 12a 11b 11a 10b 10a Experimental Design • 4 treatments • 3 replicates per treatment • 2 seed mixtures

  33. Treatments 4 treatments: • Seed-Burn-Seed • Sterile winter wheat seeded October 2004 • Burned October 2005 • Seed Only • Herbicide –Seed • Herbicide treatment – April 2005 • Unseeded Control • Perennial species Seeded in November 2005

  34. Seedings • 2 seed mixtures: Chosen assessions based on performance in Experiment 1 • Anatone bluebunch wheatgrass      • Nezpar Indian ricegrass                 • Sherman big bluegrass                  • Shaniko Plateau squirreltail            • Bannock thickspike wheatgrass     • Magnar basin wildrye          Chosen seed mixture based on performance in Experiment 2 • Anatone bluebunch wheatgrass        • High Plains Sandberg’s bluegrass        • Sand Hollow squirreltail                   • Globe mallow                                 • Eagle yarrow                                 • Wyoming big sagebrush     Seeding mixtures were randomly assigned to sub- plot “a” or “b” (split-plot)

  35. Response Variables Measured • Background Plant Community • Aboveground Biomass • Plant Density • Soil Nutrients • Soil Seedbank

  36. Results: Background Plant Community • One year following treatment: • Decreases in cheatgrass cover (p=0.07) following herbicide treatment • Decrease in shrub cover (p=0.07) following burn treatment

  37. Results: Background Plant Community No significant treatment effect seen for annual forb (p=0.22), perennial forb (p=0.62), or native bunchgrass (p=0.41) cover

  38. Results: Planted Species Biomass Treatment p=0.34 Seeding p=0.12 Treatment x Seeding p=0.23 We saw no incidence of planted shrub or forb germination in Experiment 2 seeding mixtures

  39. Results: Cheatgrass Biomass *year p=0.02 Treatment p=0.31 Seeding p=0.42 Exp 1 Seeding Exp 2 Seeding

  40. Results: Annual Forb Biomass *year p=0.01 Treatment p=0.77 Seeding p=0.58 Exp 1 Seeding Exp 2 Seeding

  41. Results: Perennial Biomass • No treatment effect seen in perennial forb (p=0.82) or perennial grass (p=0.24) biomass one year following treatment

  42. Results – Planted Species Density *Treatment p=0.003 * Seeding p=0.01 Treatment x Seeding p=0.08 More germination in Exp 2 seeding plots Higest number of germinants in herbicide treatments We saw no incidence of planted shrub or forb germination in Experiment 2 seeding mixtures

  43. Results: Cheatgrass Density Treatment p=0.07 * Seeding p=0.002 Lowest cheatgrass numbers in herbicide-treated plots Difference in seedings due to planting (drill seeding vs. drill and broadcast seeding)?

  44. Results: Density • No treatment effect seen in forb (p=0.70) or bunchgrass (p=0.17) density one year following treatment

  45. Results: Soil Nutrients • Season Effect – Higher availability in later season • Early (February – April 2006) • Late (May – September 2006) *Ammonium: p<0.0001 Nitrate: p=0.07

  46. Cheatgrass Seedbank:Results Herbicide treatment significantly reduced cheatgrass litter (p<0.001) and soil (p=0.01) seedbank in first post-treatment year

  47. Conclusions • Weed management is a long-term process! • Takes time to establish desirable vegetation • Takes more than one year of treatment to control cheatgrass • So far herbicide application has been the most effective method of control • Reduction of soil N reduced cheatgrass productivity, but not practical on large scale unless: • Can establish native vegetation to reduce soil resources • Can use another means (mechanical removal, burning) to remove N from the system • Can suppress cheatgrass for > 1 season

  48. Acknowledgements • Funding: USDA CREES, NAES, BLM, USGS, USFS • Field and lab work: Laura Blonski, Jeff Burnham,Lisa Ellsworth, Jacob Landmesser, Eugenie Montblanc, Christo Morris, Kendra Moseley, Scott Shaff, Carlos Wilson, and the many volunteers and student workers who set up plots and collected and processed data. • Data analysis: David Turner, David Board, and George Fernandez – statistical consultation and expert SAS coding skills.

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