integrating weed control and restoration. the problem: cheatgrass (bromus tectorum) invasion in...

Integrating Weed Control and Restoration

The problem: Cheatgrass (Bromus tectorum) invasionin Great Basin rangelands

Why is cheatgrass so successful?

BurnedUnburned

Young & Evans(1978)

Fre

quen

cy

Prolific seed production High competitive ability

Changes disturbance regime

X

Solution

Integrating Weed Control and Restoration: Collaborators

Robert NowakHudson GlimpNancy Markee

Barry Perryman

Robert BlankTom Jones

Gene SchuppChris Call

Paul DoescherJohn Tanaka

Jeanne ChambersRobin Tausch

Dan OgleLoren St. John

Mike PellantDavid Pyke

http://www.orst.edu/

http://www.usu.edu/

http://www.nrcs.usda.gov/

http://www.usda.gov/

• Plant materials for transition stageBluebunch wheatgrass – Anatone, Goldar, P-7, P-12Snake River wheatgrass – Secar, SERDP*Basin wildrye – Magnar, TrailheadSandberg bluegrass – Hanford, High Plains,

Mountain Home, ShermanThickspike wheatgrass – Bannock, CritanaSquirreltail – Sand Hollow, Shaniko Plateau*Western yarrow – Eagle, Great NorthernScarlet globemallowSiberian wheatgrass – VavilovCrested wheatgrass – CD-IIAnnual 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'

50'

410'

50'

50'

70'

120'

10'

10'

20'

10'

Herbicide application

Individual study plots with varietal seeding randomly assigned. Each plot has 10 rows with 1‘ row spacing.


Cheatgrass

Eden Valley Izzenhood Ranch

Bio

ma

ss (

g m

-2)

0.0

0.5

1.0

1.5

2.0

Contro

l

Herbic

ide

Experiment 1: A transition stage approach• Effects of herbicide treatments:

Reduces cheatgrass

Cheatgrass


Bio

ma

ss (

g m

-2)

0.0

0.5

1.0

1.5

2.0

Contro

l

Herbic

ide

Other species



Reduces cheatgrass, but other species increase

Cheatgrass


Bio

ma

ss (

g m

-2)

0.0

0.5

1.0

1.5

2.0

Contro

l

Herbic

ide

Other species


Seeded species


Bio

ma

ss (

g m

-2)

0.00

0.01

0.02

0.03

0.04

0.05


Reduces cheatgrass, but other species increaseVariable for seeded species

Eden Valley

CD-II

Anatone

Goldar

P-12P-7

Magnar

Trailhead

Vavilov

Pla

nt d

ensi

ty (

# ft-2

)

0

1

2

3

4

Izzenhood Ranch

CD-II

Anatone

Goldar

P-12P-7

Magnar

Trailhead

Vavilov

Pla

nt d

ensi

ty (

# ft-2

)

0

1

2

3

Bluebunchwheatgrass

Basinwildrye

CWG

SibrnWG


• Success of seeded species – Nevada

Eden Valley

CD-II

Anatone

Goldar

P-12P-7

Magnar

Trailhead

Pla

nt d

ensi

ty (

# ft-2

)

0

1

2

3

4

Izzenhood Ranch

CD-II

Sand Hollow

Shaniko

Bannock

Critana

Secar

SERDP

Pla

nt d

ensi

ty (

# ft-2

)

0

1

2

3

Squirreltail

Thickspikewheatgrass

CWG

Snake Riverwheatgrass



Eden Valley

CD-II

Anatone

Goldar

P-12P-7

Magnar

Trailhead

Pla

nt d

en

sity

(#

ft-2

)

0

1

2

3

4

Izzenhood Ranch

CD-II

Hanford

High Plains

Mtn. Hom

e

Sherman

Mountain rye

Stani

Regreen

Pioneer

Pla

nt d

en

sity

(#

ft-2

)

0

1

2

3

Sandbergbluegrass

Cerealgrasses

CWG




• Success of seeded species – All sitesBest performers (comparable to crested wheatgrass):

Anatone & P-12 bluebunch wheatgrassSERDP & Secar Snake River wheatgrassCritana thickspike wheatgrassSherman sandberg bluegrass

• Cheatgrass inhibited by low soil nitrogen,but natives are tolerant of low nitrogen

Experiment 2: A plant functional type approach


• Soil amendments to tie up nitrogen



• Soil amendments to tie up nitrogen (sucrose)• Mix of natives to deplete resources

sagebrush – evergreen; extensive rootingHigh Plains bluegrass – earliest; shallowestSand Hollow squirreltail – early; shallowAnatone bluebunch wheatgrass – mid; extensiveGreat Northern yarrow – mid; surface root matscarlet globemallow – early; extensive


No sugarSugar applicationHerbicide application

300'

350'15 m 15 m

15 m

15 m

2.5

m

1.5 m

2 m 2 m

2 m

2 m

15.5 m

23 m

Individual study plots with seeding treatments randomly assigned


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 2003 - Jan 2004 Jan 2004 - March 2004

P=0.02

P<0.001Mic

rogr

ams

NO

3 pe

r da

y1. 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)

BRTE density, 2004 seedings

planted species

estim

ated

pla

nts

per m

2

0

500

1000

1500

2000

2500

3000

no sugar sugar

BRTE density, 2003 seedings

planted species

estim

ated

pla

nts

per m

2

0

500

1000

1500

2000

2500

3000

no sugar sugar

3.1 Did the 6 species mix reduce cheatgrass?

sugar: p = 0.02 species: p = 0.001 species: p= 0.01

Low precipitation

ID NV OR UT0

10

20

30

40

50

60

70

80

High precipitation

ID NV OR UT

Se

ed

s p

er

pla

nt

0

20

40

60

80

100

120

140

160

180

No sucroseSucrose

Low precipitation

ID NV OR UT0.0

0.1

0.2

0.3

0.4

0.5

0.6

3.2 Was cheatgrass seed output, biomass or density reduced?

P = 0.0004

P = 0.005

Experiment 2: A plant functional type approach• Effects of sugar treatments:

Reduces cheatgrass biomass and seed productionConsistent effect among all sites

Cheatgrass seed production (per plant)

Effect size

-2.0 -1.5 -1.0 -0.5 0.0 0.5

Eden Valley

Izzenhood Ranch

Simpson Springs

Vernon Hills

Cinder Cone

Canyon Creek

Lincoln Bench

Succor Creek

Conclusions1. Did sucrose reduce soil N? YES

2. How well did ‘target species’ establish?1. Did sucrose facilitate establishment? No2. Did cheatgrass alter native recruitment? yes

3. Was cheatgrass adversely affected?1. Did the 6-species mix reduce cheatgrass?

NO2. 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

TreatmentControlSeed-BurnHerbicideUnseeded Control

1a

2b2a

1b

3a3b

4b4a

5a5b

6a 6b

10a10b11b11a

12a12b

7a 7b

8b8a

9a

9b

Transect 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

Cheatgrass Cover

Treatment

herbicide seed/burn seeded controlunseeded control

Pe

rce

nt

Co

ver

0

20

40

60

80

100

Experiment 1 seedingExperiment 2 seeding

Shrub Cover

Treatment


Pe

rce

nt

Co

ver

0

2

4

6

8

10

Experiment 1 Seeding Experiment 2 Seeding

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

Perennial Forb Cover

Treatment


Pe

rce

nt

Co

ver

0

20

40

60

80

100

Experiment 1 SeedingExperiment 2 Seeding

Annual Forb Cover

Treatment


Pe

rce

nt

Co

ver

0

20

40

60

80

100

Experiment 1 Seeding Experiment 2 Seeding

Bunchgrass Cover

Treatment


Pe

rce

nt

Co

ver

0

5

10

15

20

Experiment 1 SeedingExperiment 2 Seeding

Results: Planted Species Biomass

Treatment

herbicide seeded control burn

Tar

get

Bio

mas

s (g

/m2)

0.0

0.1

0.2

0.3

0.4

Exp. 1 SeedingExp. 2 Seeding

Treatment p=0.34Seeding p=0.12Treatment x Seeding p=0.23

We saw no incidence of planted shrub or forb germination in Experiment 2 seeding mixtures

Results: Cheatgrass Biomass

Cheatgrass Biomass - Experiment 2 Seeding

Treatment

Bio

mas

s (g

/m2)

0

5

10

15

20

25

30

35

2005 2006

Cheatgrass Biomass - Experiment 1 seeding

Treatment

Bio

mas

s (g

/m2 )

0

5

10

15

20

25

30

35

2005 2006

*year p=0.02Treatment p=0.31Seeding p=0.42

Exp 1 Seeding Exp 2 Seeding

Results: Annual Forb Biomass

Annual Forb Biomass - Experiment 2 Seeding

Treatment

Biom

ass

(g/m

2 )

0

10

20

30

40

50

2005 2006

Annual Forb Biomass - Experiment 1 Seeding

Treatment

Biom

ass

(g/m

2 )

0

10

20

30

40

50

2005 2006

Exp 1 Seeding Exp 2 Seeding

*year p=0.01Treatment p=0.77Seeding 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

Planted Species Density by Experimental Treatment and Seeding Treatment

Treatment

herbseed burn

seeded control

Den

sity

(In

divi

dual

s/m

2)

0

5

10

15

20

25

30

Seeding 1 Seeding 2

*Treatment p=0.003

* Seeding p=0.01Treatment 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

herb burn seeded control unseeded control

sqrt

BR

TE

/m2

0

10

20

30

40

50

Exp 1 SeedingExp 2 Seeding

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)

Resin capsule ammonium

Treatment

Control Herbicide Seed-Burn Seeding Control

Ug

per

day

NH

4

0.0

0.5

1.0

1.5

2.0

2.5

2/7/06-4/28/06 4/29/06-9/14/06

Resin capsule nitrate

Treatment

Control Herbicide Seed-Burn Seeding Control

Ug

pe

r d

ay

NO

3

0

1

2

3

4

5

6

2/7/06-4/28/06 4/29/06-9/14/06

*Ammonium: p<0.0001 Nitrate: p=0.07

Cheatgrass Seedbank:Results

Cheatgrass Seedbank

Treatment

burn herbicide seeded control unseeded control

0

1

2

3

4

5

6

sqrt litter sqrt soil

Sqr

t G

erm

inan

ts/m

2

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

Conclusions1. 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.

http://www.orst.edu/

http://www.usu.edu/

http://www.nrcs.usda.gov/

http://www.usda.gov/

integrating weed control and restoration. the problem: cheatgrass (bromus tectorum) invasion in...

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