Transcript Problem

Seminars
1. “Plant Talk” – Thurs April 8 12:00 PM in FA 214.
Eric Petersen: “Using remote sensing to
estimate the distribution of cheatgrass in
Nevada.”
2. EECB Colloquium OSN 102 at 4:00 PM
Thursday April 8. Graham Hickling, Michigan
State. "Emerging Disease in Wildlife
Populations: Bovine Tuberculosis as a Case
Study”
Reading
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D’Antonio, C., and Vitousek, P. 1992. Biological
invasions by exotic grasses, the grass fire cycle,
and global change. Ann. Rev. Ecol. Syst. 23:
63-87.
FYI: Pellant, M. 1996. Cheatgrass: the invader
that won the West. BLM Interior Columbia Basin
Ecosystem Management Project report:
http://www.icbemp.gov/science/pellant.pdf
Outline
1.
2.
3.
4.
5.
6.
Extent of cheatgrass invasion
Distribution and history of invasion
Why is cheatgrass a good invader?
What are the problems?
How can we reverse the process?
“Integrating weed control and restoration”
project
7. Discussion
Extent of cheatgrass invasion
in Great Basin
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Bromus tectorum dominates 3 million acres
Another 14 million acres are invaded
60 million acres are vulnerable to invasion
Oregon
Idaho
Nevada
Utah
Cheatgrass dominated
Cheatgrass invading
Cheatgrass susceptible
Origin and history
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Bromus tectorum originally from SW Asia and
middle east
Introduced as contaminant in wheat seed
First records in southern BC, eastern
Washington
Spread quickly, but didn’t become dominant.
Current distribution reached by around 1930.
Why could it invade and become dominant?
Why could invasion occur?
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Opportunistic
Prolific seeder
Plastic life history (winter or spring annual)
Good competitor
Somewhat grazing tolerant
Changes fire regime
“pre-adapted” to cold desert conditions
Suppression of native community by grazing?
What is the problem?
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Loss of perennial species and wildlife habitat
Increase in fire frequency (damaging and costly)
Hard seeds injure stock
Good fodder for short period only
Problem
 Loss of native rangelands
Why?
 Invasive weeds (cheatgrass)
Why?
 Fires
Problem
Problem
Problem
Problem
Problem
Problem
Problem
Solution
X
Solution
X
How?
1. A transition stage
• State and transition ecological model
Natives
Cheatgrass
How?
1. A transition stage
• State and transition ecological model
Natives
Natives
Transition
Cheatgrass
Cheatgrass
Rangeland restoration project
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First – identify promising commercially available
species and varieties for restoration planting
(Experiment 1)
Second – investigate competitive ability of
cheatgrass and planted native community.
Close the open niche for cheatgrass
(Experiment 2)
Third – demonstrate management options on
larger scale (Experiment 3)
Collaborative project:
Oregon
Idaho
Nevada
Utah
Cheatgrass dominated
Cheatgrass invading
Cheatgrass susceptible
•Bob Nowak
•Bob Blank
•Chris Call
•Jeanne Chambers
•Paul Doescher
•Hudson Glimp
•Tom Jones
•Nancy Markee
•Dan Ogle
•Mike Pellant
•Barry Perryman
•Dave Pyke
•Allen Rasmussen
•Gene Schupp
•John Tanaka
•Robin Tausch
UNR NRES
USDA ARS
Utah State University
USFS RMRL
Oregon State University
UNR CABNR
USDA ARS
UNR CABNR
NRCS Plant Materials Center
BLM Idaho State Office
UNR CABNR
USGS FRESC
Utah State University
Utah State University
Oregon State University
USFS RMRL
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Experiment 1: agronomic trials of drill-seeded
species
Thurber’s needlegrass – Orchard
Bluebunch wheatgrass – Goldar, Anatone, P-5
Thickspike wheatgrass – Critana, Bannock
Snake River wheatgrass – Secar, KBJ
Squirreltail – Sand Hollow, 2nd accession
Indian ricegrass – Nezpar, Rimrock, Rimrock HG
Basin wildrye – Magnar, Trailhead, NV MOPX
Bluegrass – Sherman, High Plains, Mountain Home
Crested wheatgrass – Vavilov, CD-2
Wheat sterile hybrids (3 varieties)
Plants of local interest – Shadscale, winterfat
Globemallow
Izzenhood Ranch Study Site
8-10“ precipitation zone
Eden Valley Study Site
10-12“ precipitation zone
Experiment 1 procedure
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Drill-seeded into 10’ by 20’ trial plots, 6 blocks at
each study site. Planted November 2003.
3 blocks sprayed with post-emergent herbicide, 3
not sprayed
Growth, survival, biomass of planted species will
be monitored.
Results so far – differences among emergence rate
of different accessions;
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 2
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Seed monocultures of accessions, native species
mix (6 species with range of growth forms) +
cheatgrass
Add labile carbon (sucrose) to ½ plots to sequester
N
Monitor emergence, growth and survival of both
planted species and cheatgrass
Preliminary results – carbon addition appears to
reduce emergence of both natives and cheatgrass,
but cheatgrass suppressed more (3X)
Experiment 2
Reduce soil nitrogen
• Cheatgrass inhibited by low soil nitrogen,
Natives are tolerant of low nitrogen
• Soil amendments to tie up nitrogen
• Mix of natives to deplete resources
sagebrush, yarrow, globe mallow, bluegrass
squirreltail, bluebunch wheatgrass
300'
Herbicide application
Sugar application
No sugar
15 m
350'
15 m
15 m
Individual study plots
with seeding treatments
randomly assigned
15 m
2.5 m
1.5 m
15.5 m
2m
2m
2m
2m
23 m
Experiment 3
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Demonstration of potential management
techniques on larger scale (3 ha)
To be implemented Autumn 2004
Location – Biddell Flats (25 miles north of Reno)
How?
1. A transition stage
2. Reduce soil nitrogen
3. Large-scale restoration trials
• Transition community vs. Native mix
• Restoration treatments targeted at:
reduce cheatgrass seedbank
reduce soil N
4. Treatments:
1. Control – no treatment
2. Burn-seed-burn-seed: to reduce cheatgrass seedbank.
Transitional community. Sterile hybrid.
3. Grazing to reduce cheatgrass seed set
4. Herbicide (‘gold standard’ for control)
5. Burning and grazing combination
5,250'
Best
accessions
Control
200 m
200 m
Mixed
species
Burn-Seed-Burn-Seed
Herbicide
100 m
100 m
4,140'
Grazing
Burn-Graze
100 m
15 m spacing
Exotic Species Cover (%)
Benefits
30
25
A
R2 = 0.160
P = 0.005
1. Restore
land health
20
2. Invasive species control
15
• Reduce cheatgrass
10
• Reduce
secondary weeds (knapweed,
5starthistle, skeletonweed)
0
• Restoration
also reduces invasibility
Bromus tectorum Cover (%)
30
25
B
R2 = 0.096
P = 0.032
20
15
10
5
0
10
20
30
40
50
Native Species Cover (%)
60
Anderson & Inouye (2001)
My research
What makes rangeland invasible in the first place?
Common knowledge – shrub steppe is resistant to invasion
unless overgrazed.
BUT – cheatgrass is “pre-adapted” to cold desert conditions
- there are few native annual species (vacant niche?)
- there is a large amount of empty space even in healthy
community
- resources are variable; could pulsing of resources allow
invasion?
Greenhouse studies (individual plant performance, mesocosms,
field test)
Questions for discussion
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What principles of ecology are we applying?
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How does understanding ecology of the system help
the design and interpretation of the experiment?