Integrating Weed Control and Restoration

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

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

Changes disturbance regime

X Solution

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

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 Experiment 1: A transition stage approach

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

Effects of herbicide treatments: Reduces cheatgrass

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

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

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

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

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

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

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

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

Specific questions 1.Did sucrose reduce soil N? 2.Did the ‘target species’ benefit? 1.Did sucrose facilitate establishment? 2.Did cheatgrass reduce native recruitment? 3.Was cheatgrass adversely affected? 1.Did the 6-species mix reduce cheatgrass? 2.Was cheatgrass seed output, biomass, or density reduced?

Oct Jan 2004 Jan March 2004 P=0.02 P<0.001 Micrograms NO 3 per day 1.Did sucrose reduce soil N ?

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

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)

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

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

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

Conclusions 1.Did sucrose reduce soil N?YES 2.How well did ‘target species’ establish? 1.Did sucrose facilitate establishment? No 2.Did cheatgrass alter native recruitment? yes 3.Was cheatgrass adversely affected? 1.Did the 6-species mix reduce cheatgrass? NO 2.Was cheatgrass seed output, biomass, or density reduced? Sucrose YES, species mix NO; effect short-lived

Experiment 3: Large-scale restoration trials

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

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

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

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

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

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) Seedings

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

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

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

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

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

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

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

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

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)?

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

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

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

Conclusions 1.Weed management is a long-term process! Takes time to establish desirable vegetation Takes more than one year of treatment to control cheatgrass 2.So far herbicide application has been the most effective method of control 3.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

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.