Ecological Archives E088-026-A2
F. Leland Russell, Svata M. Louda, Tatyana A. Rand, and Steven D. Kachman. 2007. Variation in herbivore-mediated indirect effects of an invasive plant on a native plant. Ecology 88:413–423.
Appendix B. ANCOVA results for effects of Rhinocyllus conicus density in the focal musk thistle patch and distance to the focal patch on R. conicus egg load on wavyleaf thistles. Distance × year is included as a random effect. Wavyleaf thistle size, measured as number of flower heads per plant, is the covariate.
Source |
Numerator df
|
Denominator df
|
F
|
P
|
|
|
|
|
|
R. conicus density |
1
|
33.5
|
5.08
|
0.0308
|
Distance |
3
|
10.5
|
15.07
|
0.0004
|
R. conicus density × distance |
3
|
78
|
1.24
|
0.2994
|
Wavyleaf thistle size |
1
|
1033
|
12.30
|
0.0005
|
Size × R. conicus density |
1
|
1033
|
0.15
|
0.6987
|
Size × Distance |
3
|
1029
|
2.17
|
0.0904
|
Size × R. conicus density × distance |
3
|
1021
|
0.96
|
0.4116
|
A posteriori comparisons of least square means among treatment levels for R. conicus density and distance using protected least significant differences.
Source |
Treatment level
|
Treatment level
|
Estimate
|
Standard Error
|
df
|
t value
|
P
|
R. conicus density |
High
|
Low
|
0.2799
|
0.1210
|
33.4
|
2.31
|
0.0271
|
Distance |
Far
|
In
|
-0.7071
|
0.1314
|
13.5
|
-5.38
|
0.0001
|
Distance |
Far
|
Mid
|
-0.0589
|
0.1325
|
13.7
|
-0.45
|
0.6632
|
Distance |
Far
|
Near
|
-0.2675
|
0.1331
|
13.8
|
-2.01
|
0.0644
|
Distance |
In
|
Mid
|
0.6481
|
0.1151
|
8.56
|
5.63
|
0.0004
|
Distance |
In
|
Near
|
0.4396
|
0.1156
|
8.69
|
3.80
|
0.0045
|
Distance |
Mid
|
Near
|
-0.2085
|
0.1164
|
8.84
|
-1.79
|
0.1073
|
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