The Role of Native Annual Forbs in the
Restoration of Invaded Rangelands
Erin Goergen, Elizabeth Leger, Tara Forbis
University of Nevada, Reno
USDA ARS Reno, NV
Restoration of degraded communities
is costly and difficult.
Restoration of degraded communities
is costly and difficult.
• Weather
• Seeding method
• Seeds
• Species mixes
Natural Succession
Disturbance
Annuals
Early seral
perennials
Late seral
perennials &
shrubs
•
•
•
•
•
•
Seed Mix 1
Artemisia tridentata
Elymus lanceolatus
Leymus cinereus
Poa secunda
Pseudoroegneria spicata
Achillea millefolium
•
•
•
•
•
Seed Mix 2
Artemisia tridentata
Achnatherum hymenoides
Elymus lanceolatus
Poa secunda
Pseudoroegneria spicata
Seed Mix 3
•
•
•
•
•
•
•
•
•
•
•
Artemisia tridentata
Purshia tridentata
Achnatherum hymenoides
Agropyron crestatum
Elymus lanceolatus
Leymus cinereus
Pascopyrum smithii
Poa secunda
Pseudoroegneria spicata
Achillea millefolium
Medicago sativa
Can we improve restoration success by
more closely following natural
successional patterns?
Disturbance
Annuals
Early seral
perennials
Late seral
perennials &
shrubs
Native annual forbs may be valuable
restoration species for multiple reasons
1. Adapted to post-disturbance
environmental conditions.
2. Likely to be phenologically similar to
and competitive with Bromus tectorum.
3. Contribute to plant diversity and habitat
in rangelands.
Native annuals can be abundant!
Annuals increase after disturbance!
• Native annual forbs have relatively low
abundance in climax sagebrush
communities.
• Underdown Canyon, Austin NV
– 1 year after fire, native annual forbs increased
by 70%
– Cover stayed high even 3 years post-fire
Annuals are good competitors!
Cryptantha pterocarya
25 – 85% reduced!
Collinsia parviflora
25 – 35% reduced!
There is overlap in phenology
Fall
Winter
Spring
Bromus tectorum
Annual forbs
Forbis (2010) Plant Species Biology 25:221-230
Summer
Fall
_
B. tectorum
Native perennial
grasses
Native annual forbs
_
_
_
B. tectorum
Native perennial
grasses
Native annual forbs
_
+
_
_
B. tectorum
Native perennial
grasses
Can seeding native annual forbs improve
establishment of the short-lived, native
perennial grass Elymus multisetus?
Questions
1. What is the effect of individual
annuals, on Elymus multisetus and
Bromus tectorum?
2.When grown in mixtures, what effect
do annual forbs have on Elymus
multisetus and Bromus tectorum?
Field Experiment
• Target E. multisetus and B. tectorum
– grown alone, with single annual forb species,
B. tectorum, or forb + B. tectorum.
• 5 Native forbs chosen:
Amsinckia tesellata
AMTE
Amsinckia intermedia
AMIN
Mentzelia veatchiana
MEVE
Descurinia pinnata
DEPI
Blepharipappus
scaber BLSC
Experimental Design
Target: Elymus multisetus or Bromus tectorum
Competitors: none, annual forb, B. tectorum, or both
Seeds were sown around a target
plant at typical field densities
Questions
1.What is the effect of
individual annuals, on target
Elymus multisetus and
Bromus tectorum?
1. ELMU grows best with BLSC,
DEPI, and MEVE
E. multesitus aboveground biomass (g)
A
AB
1
70%
75%
83%
0.5
B
94%
99%
97%
0
AMTE
AMIN
BRTE
MEVE
DEPI
BLSC
1. Competitive pressure on BRTE
is not equal!
B. tectorum vegetative biomass (g)
3.5
A
AB
3
38%
2.5
46%
2
59%
1.5
BC
1
C
0.5
84%
88%
97%
0
AMTE
BRTE
AMIN
MEVE
DEPI
BLSC
Questions
2. When grown in mixtures, what effect
do annual forbs have on Elymus
multisetus and Bromus tectorum?
MEVE and BRTE
AM and BRTE
2. When with BRTE, ELMU is larger when
MEVE is also present.
E. multesitus aboveground biomass (g)
0.5
71%
0.4
0.3
27%
0.2
BRTE
60%
0.1
79%
95%
0
BRTE+AMTE
BRTE+AMIN
BRTE+DEPI
BRTE+BLSC
BRTE+MEVE
2. BRTE is most impacted when
grown with AMTE and AMIN.
A
B. tectorum vegetative biomass (g)
1
90%
AB
0.5
6%
7%
BC
51%
C 88%
0
BRTE+AMTE
BRTE+AMIN
BRTE+DEPI
BRTE+MEVE
BRTE+BLSC
Field summary
• A. tesselata and A. intermedia show
promise as a good competitors against
B. tectorum.
• M. veatchiana has the potential to
facilitate establishment of E. multisetus.
Next steps
• Multiple years!
• We need to learn more about our native
annual forbs!
– Germination strategies
– Dormancy issues
– Competitive abilities
Questions?