Ecological Archives E095-128-A1
Matthew E. S. Bracken, Renee E. Dolecal, Jeremy D. Long. 2014. Community context mediates the top-down vs. bottom-up effects of grazers on rocky shores. Ecology 95:1458–1463. http://dx.doi.org/10.1890/13-2094.1
Appendix A. Tables showing output from general linear models.
Table A1. Ammonium concentrations.
(a) Overall model
Source
df
Sum of squares
Mean Square
F value
P value
Model
9
82.86
9.21
7.12
< 0.001
Error
288
372.29
1.29
Corrected Total
297
455.16
(b) Treatment effects
Treatment
df
Type III SS
Mean Square
F value
P value
Species
2
8.13
4.06
3.14
0.045
Grazer
2
63.29
31.65
24.48
< 0.001
Species × Grazer
4
7.41
1.85
1.43
0.223
Biomass
1
4.94
4.95
3.83
0.051
Table A2. Effects on Fucus growth.
(a) Consumptive effects
Overall model
Source
df
Sum of squares
Mean Square
F value
P value
Model
2
96.26
48.13
2.05
0.138
Error
57
1,336.24
23.44
Corrected Total
59
1,432.51
Treatment effects
Treatment
df
Type III SS
Mean Square
F value
P value
Ulva
1
1.82
1.82
0.08
0.781
Biomass
1
59.92
59.92
2.56
0.115
(b) Facilitative effects
Overall model
Source
df
Sum of squares
Mean Square
F value
P value
Model
2
67.86
33.93
2.84
0.067
Error
57
681.80
11.96
Corrected Total
59
749.65
Treatment effects
Treatment
df
Type III SS
Mean Square
F value
P value
Ulva
1
67.83
67.83
5.67
0.021
Biomass
1
15.73
15.73
1.32
0.256
(c) Total herbivore effects
Overall model
Source
df
Sum of squares
Mean Square
F value
P value
Model
2
189.76
94.88
4.15
0.021
Error
57
1,304.35
22.88
Corrected Total
59
1,494.11
Treatment effects
Treatment
df
Type III SS
Mean Square
F value
P value
Ulva
1
91.89
91.89
4.02
0.049
Biomass
1
14.25
14.25
0.62
0.433
Table A3. Effects on Ulva growth.
(a) Consumptive effects
Overall model
Source
df
Sum of squares
Mean Square
F value
P value
Model
2
9,036.48
4,518.24
13.85
< 0.001
Error
57
18,590.53
326.15
Corrected Total
59
27,627.01
Treatment effects
Treatment
df
Type III SS
Mean Square
F value
P value
Fucus
1
2,845.61
2,845.61
8.72
0.005
Biomass
1
8,989.47
8,989.47
27.56
< 0.001
(b) Facilitative effects
Overall model
Source
df
Sum of squares
Mean Square
F value
P value
Model
2
270.57
135.28
0.27
0.764
Error
57
28,545.08
500.79
Corrected Total
59
28,815.65
Treatment effects
Treatment
df
Type III SS
Mean Square
F value
P value
Fucus
1
160.57
160.57
0.32
0.574
Biomass
1
7.55
7.55
0.02
0.903
(c) Total herbivore effects
Overall model
Source
df
Sum of squares
Mean Square
F value
P value
Model
2
9,605.60
4,802.80
7.80
0.001
Error
57
35,098.73
615.77
Corrected Total
59
44,704.33
Treatment effects
Treatment
df
Type III SS
Mean Square
F value
P value
Fucus
1
1,654.27
1,654.27
2.69
0.107
Biomass
1
9,517.97
9,517.97
15.46
< 0.001