McAbee et al. Online Resources
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Online Resource 1. Variation in soil temperature at 0-15-cm depths between May 15 and
September 12, 2014 in A. cristatum monoculture plots (panel A) and native sagebrush steppe
vegetation plots (panel B). Data collection coincided with Rsoil measurements, and symbols
-June are missing due to equipment failure.
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Time
Interval
Vegetation
Campaign
Date
1-Jul
Overall F
12.22
Overall P
0.0077
AMB > SUM
0.0062
Native
29-Jul
25.49
0.0012
AMB > SUM
0.0010
WIN > SUM
0.0133
4-Jun
12.45
0.0073
AMB > WIN
0.0095
SUM > WIN
0.0152
12-Aug
20.61
0.0177
AMB > SUM
0.0164
5.5
0.0440
WIN > SUM
All two-way P >
0.05
0.0488
1-May
15-May
5.71
0.0409
WIN > SUM
0.0365
18-Jun
98.53
0.0018
WIN > AMB
0.002
WIN > SUM
0.0033
29-Jul
15.64
0.0042
SUM > AMB
0.0049
SUM > WIN
0.0109
12-Aug
5.94
0.0378
SUM > AMB
0.0442
15-May
6.41
0.0324
WIN > SUM
0.0335
4-Jun
31.05
0.0007
WIN > SUM
0.0011
WIN > AMB
0.0013
18-Jun
33.96
0.0087
WIN > SUM
0.0096
WIN > AMB
0.0149
1-Jul
8.73
0.0167
WIN > AMB
0.0170
WIN > SUM
0.0490
Dawn
CWG
Native
Mid-Day
CWG
Evening
CWG
Post-Hoc
Comparison
Tukey's
P
29-Jul
6.16
0.0351
SUM > AMB
0.0322
12-Sep
5.62
0.0422
SUM > WIN
0.0395
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Online Resource 2. Summary ANOVA table for the effects of irrigation (ambient, +summer,
+winter) on NEE within each campaign date and within vegetation treatment (A. cristatum and
native sagebrush steppe), with post-hoc Tukey comparisons. Only dates at which an overall
effect (P < 0.05) was detected are recorded.
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Online Resource 3. Dawn, mid-day, and evening Anet of the three most abundant plant species
(A. cristatum, H. boreale, and A. tridentata) averaged across the growing season. Letters
indicate which species groups are significantly different from others (P < 0.05) within a single
diurnal interval. Error bars represent one standard error of the mean. Because Anet means did not
vary significantly across the growing season, or between vegetation and irrigation treatments,
these data represent means across those variables. Here, greater dark respiration (Anet measured at
dawn interval) is indicated by a more negative Anet.
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Online Resource 4. Seasonal variation in Anet of the three most abundant plant species in native
vegetation plots (A. cristatum, a-c; H. boreale, d-f; A. tridentata, g-i).
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Online Resource 5. Variation in leaf-level Anet with soil volumetric water content at dawn (top
panels) and midday (bottom panels) among ambient, summer, and winter plots. Soil moisture
data are averaged across 0.2-1.0 m depths. Panels A and B present Anet averaged across all plant
species available at the time of each measurement campaign. Panels C and D present Anet for A.
tridentata shrubs only (the dominant plant in each plot). Because moisture sensors were located
only in native vegetation plots, Anet data are presented only for native vegetation plots (no data
presented for A. cristatum monoculture plots). No regression lines are displayed because R2
values were less than 0.31 and P values were greater than 0.21 for all fits.
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Time
Interval
Vegetation
Native
Campaign
Date
1-Jul
Overall F
11.71
Overall P
0.0085
SUM > AMB
0.0277
SUM > WIN
0.0017
SUM > AMB
0.0004
WIN > SUM
0.0021
WIN > AMB
0.0089
4-Jun
20.31
0.0021
1-Jul
8.61
0.0173
WIN > AMB
0.0152
15-Jul
9.16
0.0150
SUM > AMB
0.0123
29-Jul
9.90
0.0126
SUM > WIN
0.0448
SUM > AMB
0.0121
WIN > SUM
0.0364
WIN > AMB
0.0087
SUM > WIN
0.0015
SUM > AMB
0.0002
SUM > WIN
0.0118
SUM > AMB
0.0039
SUM > WIN
0.0019
SUM > AMB
0.0023
SUM > WIN
0.0006
SUM > AMB
0.0002
SUM > WIN
0.0027
SUM > AMB
0.0006
Native
29-Jul
15-Jul
CWG
29-Jul
Native
29-Jul
CWG
0.0086
0.0004
15-Jul
Evening *†
WIN > AMB
39.27
4-Jun
Mid-Day
Tukey's P
29-Jul
Dawn *
CWG
Post-Hoc
Comparison
11.33
44.46
16.51
34.14
52.08
32.09
0.0092
0.0003
0.0036
0.0012
0.0002
0.0006
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* Excludes data from campaign dates specified in Table 4 footnotes.
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† SUM Rsoil marginally greater than AMB Rsoil in Native (P = 0.0543) and CWG plots (P = 0.0513) in July
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Online Resource 6. Summary ANOVA table of the effects of irrigation treatments (ambient,
+summer, +winter) on across-species Rsoil within each campaign date and within vegetation
treatment (A. cristatum and native sagebrush steppe), with post-hoc Tukey comparisons. Only
dates at which an overall effect (P < 0.05) was detected are recorded.
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