Seedling Root Traits
and Field Performance
of Elymus elymoides
Daniel Z Atwater
Jeremy J James
Elizabeth A Leger
Jeremy James and colleagues
Rangeland Restoration Project
Goal: To systematically improve our understanding of
factors that influence native plant restoration and
seedling establishment in the northern Great Basin.
My Module
How do root traits affect
native plant establishment in
burned and invaded sites in
the Great Basin?
• Ecology
• Screening & selection of
restoration material in
degraded rangeland
Focal plant: Elymus elymoies
(and Bromus tectorum)
The Importance of Root Traits
Question: How do root traits affect Elymus establishment
in the Great Basin?
1. Get Seeds from 100
mothers at two sites
The Importance of Root Traits
Question: How do root traits affect Elymus establishment
in the Great Basin?
1. Get Seeds from 100
mothers at two sites
2. Plant seeds in
greenhouse
3. Measure root traits in
10-day seedlings
The Importance of Root Traits
Question: How do root traits affect Elymus establishment
in the Great Basin?
1. Get Seeds from 100
mothers at two sites
2. Plant seeds in
greenhouse
3. Measure root traits in
10-day seedlings
4. Plant seeds in the field
(November)
5. Measure at end of
growing season (June)
The Importance of Root Traits
Question: How do root traits affect Elymus establishment
in the Great Basin?
Sub Questions:
1. Which traits should we investigate?
2. Is variation in root traits heritable?
3. Does variation in root traits affect survival
and size after one growing season?
4. What role does seed mass play?
The Importance of Root Traits
1) Which traits?
Length
Surface Area
Diameter
Specific Root Length
Volume
Tips
Root Mass Ratio
PC1
PC2
PC3
0.98 -0.02
0.08
0.96
0.21
0.07
0.04
0.98 -0.02
-0.08 -0.97 -0.04
0.89
0.40
0.06
0.81 -0.16
0.06
0.11
0.01
0.99
The Importance of Root Traits
1) Which traits?
Length
Surface Area
Diameter
Specific Root Length
Volume
Tips
Root Mass Ratio
PC1
PC2
PC3
0.98 -0.02
0.08
0.96
0.21
0.07
0.04
0.98 -0.02
-0.08 -0.97 -0.04
0.89
0.40
0.06
0.81 -0.16
0.06
0.11
0.01
0.99
The Importance of Root Traits
Question: How do root traits affect native plant
establishment in the Great Basin?
Sub Questions:
1. Which traits should we investigate? Selected some
2. Is variation in root traits heritable?
3. Does variation in root traits affect survival and size
after one growing season?
4. What role does seed mass play?
The Importance of Root Traits
Question: How do root traits affect native plant
establishment in the Great Basin?
Sub Questions:
1. Which traits should we investigate? Selected some
2. Is variation in root traits heritable? YES
3. Does variation in root traits affect survival and size
after one growing season?
4. What role does seed mass play?
3) Does root trait variation influence field performance?
Emergence:
Photo: Seeds of Success
3) Does root trait variation influence field performance?
Survival:
Paradise
Orovada
0.132
0.126†
Length
0.418**
0.007
Length2
-0.115†
-0.185*
SRL
-0.224
0.039
Tips
0.258*
-0.090
Tips2
-0.159
RMR
-0.125
RMR2
-0.182*
DTE
-0.104
Seed
0.071
-0.119
Paradise
Orovada
3) Does root trait variation influence field performance?
Height at Paradise:
β
Seed
0.157*
Length
0.203*
Length2
SRL
-0.168*
Tips
0.111†
Tips2
-0.123**
RMR
-0.183*
RMR2
DTE
-0.155
3) Does root trait variation influence field performance?
Height at Orovada:
β
Seed
0.095†
Length
Length2
SRL
0.104†
Tips
0.096†
Tips2
RMR
RMR2
DTE
0.116*
The Importance of Root Traits
3) Does root trait variation influence field performance?
Answer: YES, enormously…
GLMM
NA
Zero
Paradise
6.02
64.08
4.34
Orovada
1.48
1.60
1.44
Paradise
1.91
2.72
1.25
Orovada
1.24
1.26
1.08
Survival
Height
The Importance of Root Traits
4) What role does seed mass play?
Answer: Direct effects moderate to weak…
GLMM
NA
Zero
Paradise
1.42
1.48
1.22
Orovada
1.26†
1.22†
1.17
Paradise
1.27*
1.32*
1.14
Orovada
1.09
1.09†
1.03
Survival
Height
The Importance of Root Traits
4) What role does seed mass play?
Answer: Indirect effects also mostly weak…
Seed Mass
Effect of Seed Mass
on Root Traits: (?)
Direct Effect of
Seed Mass: (0.15)
Root Trait
Performance
Direct Effect of
Root Trait: (0.3)
Effect of Seed Mass
Direct
0.15
Indirect
0.3 x ?
The Importance of Root Traits
4) What role does seed mass play?
Answer: Indirect effects also mostly weak…
Seed Mass
Direct Effect of
Seed Mass: (0.15)
Performance
Effect of Seed Mass
Direct
Effect of Seed Mass
on Root Traits: (0.1)
Root Trait
Direct Effect of
Root Traits: (6.0)
0.15
Indirect 0.3 x 0.1
The Importance of Root Traits
4) What role does seed mass play?
Survival
Height
Paradise
Orovada
Paradise
Orovada
0.132
0.126
0.157
0.095
Q
Q
0.042
SRL
0.096
-0.008
0.061
-0.018
Tips
Q
-0.012
Q
0.004
RMR
Q
0.009
-0.067
0.017
DTE
0.009
0.014
-0.008
Direct
Seed
Indirect
Length
The Importance of Root Traits
Question: How do root traits affect native plant
establishment in the Great Basin?
Sub Questions:
1. Which traits should we investigate? Selected some
2. Is variation in root traits heritable? YES
3. Does variation in root traits affect survival and size
after one growing season? YES, Enormously
4. What role does seed mass play? Mild to Moderate
Other Takeaway Points
• Effects may be huge
• Intermediate values favored
• Effects vary between close
sites (< 20 mi.)
• Site “preference” predictable?
• Select restoration material
based on traits?
Future
• Sample 35 sites
throughout Great Basin
• Transplant into 5 sites
• Proximity?
• Home climate?
• Traits?
Seedling Root Traits Have Huge Effect on Performance in
the Great Basin
Potential for Ecology and Restoration
Trait
Length
SRL
Tips
RMR
DTE
H2
RLRT
0.113
7.403
0.214
23.665
0.000 NA
0.127
3.067
0.110
7.177
p
0.003
< 0.001
NA
0.038
0.003
Length
SRL
Tips
RMR
DTE
Model of Emergence
Paradise
Orovada
r
P
r
P
0.064
0.660
0.229
0.131
-0.398
0.007
-0.161
0.292
0.094
0.539
0.215
0.157
0.242
0.110
0.193
0.205
0.079
0.605
-0.160
0.295
Model of Height
Paradise
Length
SRL
Tips
RMR
DTE
r
0.209
-0.366
0.257
0.367
0.053
Orovada
P
0.174
0.014
0.092
0.014
0.735
r
0.109
-0.170
0.039
0.147
-0.258
P
0.459
0.248
0.790
0.320
0.076
Model of Survival
Paradise
Orovada
r
P
r
P
0.105
0.492
0.187
0.212
-0.427
0.003
-0.196
0.192
0.216
0.155
0.132
0.384
0.275
0.068
0.131
0.385
0.090
0.557
-0.118
0.433
Model of ln-Leaf Number
Paradise
Orovada
r
P
r
P
0.088
0.560
0.109
0.459
-0.236
0.114
-0.170
0.248
0.169
0.263
0.039
0.790
0.237
0.113
0.147
0.320
0.077
0.612
-0.258
0.076
Emergence Probability
Paradise
Seed
Length
Length2
SRL
SRL2
Tips
Tips2
RMR
RMR2
DTE
Survival Probability
Orovada
Paradise
βFull
0.185*
0.116
βNA
0.190*
0.146†
βZero
0.190
0.099
imp.
1.00
0.68
βFull
0.146†
0.09
βNA
0.157†
0.140
βZero
0.137
0.026
imp
.
0.87
0.18
0.013
-0.085
-0.017
0.20
-0.07
-0.098
-0.037
0.38
0.026
-0.062
-0.035
-0.114
-0.084
-0.085
-0.011
0.12
-0.21
-0.168
-0.105
0.63
0.012
-0.117†
-0.089
0.004
-0.041
-0.034
0.35
0.35
0.38
0.04
0.107
0.013
0.12
-0.08
-0.104
-0.044
0.42
Orovada
βFull
0.119
0.183
-0.067
-0.103
βNA
0.132
0.418**
-0.115†
-0.224
βZero
0.067
0.079
0.079
-0.065
imp.
0.51
0.19
0.19
0.29
βFull
0.141†
-0.008
-0.213†
-0.100
βNA
0.126†
0.007
-0.185*
0.039
βZero
0.100
0.007
-0.185
0.005
imp.
0.79
1.00
1.00
0.14
0.204
-0.094
-0.181
-0.103
-0.096
0.258*
-0.159
-0.125
-0.182*
-0.104
0.223
-0.067
-0.104
-0.118
-0.034
0.86
0.42
0.84
0.65
0.33
-0.097
0.057
0.142
-0.090
-0.015
0.16
0.071
0.011
0.15
-0.115
-0.119
-0.062
0.52
Height (cm)
Paradise
Seed
Length
Length2
SRL
SRL2
Tips
Tips2
RMR
RMR2
DTE
ln(Leaves)
Orovada
Paradise
βFull
0.142*
0.333**
βNA
0.157*
0.203*
βZero
0.062
0.103
imp
.
0.39
0.50
-0.129
-0.168*
-0.009
0.05
0.138*
0.106†
0.018
0.18
-0.012
-0.101*
-0.261**
0.111†
-0.123**
-0.183*
0.008
-0.005
-0.038
0.07
0.04
0.21
0.143†
0.096†
0.015
0.16
0.098†
0.116*
0.007
0.06
-0.046
-0.155
-0.016
0.10
-0.050
βFull
0.091
-0.108
βNA
0.095†
βZero
0.012
imp
.
0.13
βFull
0.012
0.119*
-0.072†
0.037
-0.009
-0.047**
-0.062
-0.007
Orovada
βNA
βZero
imp
.
0.061*
0.014
0.23
βFull
0.024
-0.038
βNA
βZero
imp
.
-0.053**
-0.03
0.56
0.02
0.044†
-0.054**
0.002
-0.003
0.05
0.05
0.053*
0.026
-0.055**
Survival
Height
Paradise
Full
NA
Orovada
Zero
Full
NA
Paradise
Zero
Full
NA
Orovada
Zero
Full
Seed Size
1.42
1.48
1.22
1.26†
1.22†
1.17
1.27*
1.32*
1.14
1.09
Length
1.89
4.22**
1.28
1.56†Q
1.42*Q
1.42
1.84**
1.50*
1.30
1.13
SRL
1.62
3.02
1.35
1.16
1.06
1.01
1.61
1.98*
1.04
Tips
1.79
2.32*
1.80
1.11
1.12
1.02
1.67*Q
1.54**Q
RMR
1.73
2.35*Q
1.63
1.18
1.09
1.01
1.60**
Root Traits
6.02
64.08
4.34
1.48
1.60
1.44
1.91
NA
Zero
1.09†
1.03
1.22*
1.16†
1.06
1.02
1.19†
1.12†
1.04
1.41*
1.10
1.19†
1.23*
1.03
2.72
1.25
1.24
1.26
1.08