Finding the Best Native Plants to
Compete with Invasive Weeds
Elizabeth Leger, Erin Espeland,
& Erin Goergen
University of Nevada, Reno
USDA ARS
The big question
• How can we find native plants that are good at
growing in invaded areas?
The big question
• How can we find native plants that are good at
growing in invaded areas?
• Variation among:
1. Species
2. Populations
3. Individuals
The goal
Native species that can grow in
disturbed areas
Poa secunda
Elymus multisetus
Collinsia parviflora
E. elymoides
Cryptantha pterocarya
Amsinckia sp.
Three methods:
1. Learn from long-term evolutionary change
•
Leger 2008; Goergen et al. 2011; Rowe and Leger 2011
2. Learn from survivors in restorations
•
Kulpa and Leger, in prep
3. Competition studies
•
Rowe and Leger 2011; Phillips and Leger, in prep; Goergen et al. in
review; Leger, et al. in prep
5 native grass species, 8 collections, 40 plants per site
Species and populations differ in
cheatgrass suppression
A
AB
AB
AB
AB
B
B
B
P < 0.0001
Can annual forbs suppress cheatgrass?
Amsinckia tesellata
AMTE
Amsinckia intermedia
AMIN
Mentzelia veatchiana
MEVE
Descurinia pinnata
DEPI
Blepharipappus
scaber BLSC
Early spring growth
Early spring growth
5 annual forbs, target cheatgrass
Annual forbs suppress cheatgrass
B. tectorum vegetative biomass (g)
3.5
AB
A
3
2.5
AB
2
1.5
1
BC
BC
0.5
C
0
AMTE
BRTE
AMIN
MEVE
DEPI
BLSC
Goergen, Leger, & Forbis; in review
AM and BRTE
Other annual weeds
Ranunculus testiculatus
Co-occurring native annual forbs
• Collinsia parviflora
• Cryptantha pterocarya
Year 1: 200 Collinsia, 300 Cryptantha
Year 2: 500 Collinsia
1000 Cryptantha; half fertilized, half unfertilized
Burr buttercup biomass (mg)
Native annuals are tough cookies
Grown alone
Grown with Collinsia
*
*
Burr buttercup biomass (mg)
Native annuals are tough cookies
Grown alone
Grown with Cryptantha
*
*
*
How do they do it?
How do they do it?
• Compare traits of successful
and unsuccessful plants
• Find things that correlate with
success
So far: early spring phenology, root traits, relative
investment in roots, change in root investment over
time, plant size
Next steps: test in the field
Acknowledgements
• USDA AFRI
• Great Basin Native Plant
•
•
•
Selection and Increase
Project
University of Nevada, Reno
Nevada Bureau of Land
Management
California Department of
Fish and Game
Questions
What traits increase establishment,
competitive ability?
• Early green-up (adult grasses)
• Early root growth, fine root production, increased
root tips (Elymus multisetus seedlings)
• Early germination (Elymus elymoides seedlings)
• Small plant size (Annual forbs, E. multisetus, E.
elymoides adults and seedlings)
• Increased allocation to reproduction (Poa
secunda)
• Initial investment in fine roots, later investment in
coarse roots (Poa secunda)
Can native annuals facilitate the
establishment of native grasses?
Elymus multisetus
Can native annuals facilitate the
establishment of native grasses?
Squirreltail growth rate (leaves d-1)
0.06
A
A
0.04
A
0.02
B
0
-0.02
8 BRTE
BRTE+MEVE
BRTE+AMTE
BRTE+FORB MIX
Competitors are larger when
family mean roots are longer
Competitor mass (g)
Collinsia
Length of 0.1-1.15 mm roots (cm)
Competitors are larger when
family mean sizes are larger
Competitor mass (g)
Cryptantha
Target shoot mass (g)
Competitors are larger when
family mean sizes are larger
Competitor mass (g)
Eriastrum
Target shoot mass (g)