Appendix A. ANOVA results for snail species richness and composition effects.
ANOVA results for snail species richness and composition effects on (A) snail, periphyton, and macrophyte biomass and (B) sedimentation rate, dissolved oxygen concentration, and total system organic matter. Periphyton, organic matter, and sedimentation data were log transformed prior to analyses. Dissolved oxygen and periphyton data were means of several repeated measures. Response variables with error degrees of freedom not equal to 75 had missing data for one or two microcosms.
A) Functional group biomass |
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Snail biomass |
Periphyton biomass |
Plant biomass |
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Source |
df |
MS |
F |
P |
df |
MS |
F |
P |
df |
MS |
F |
P |
Species richness |
1 |
14842 |
29.328 |
<0.0001 |
1 |
0.807 |
4.162 |
0.0449 |
1 |
0.482 |
1.527 |
0.2204 |
Composition (SR) |
19 |
4118.8 |
8.138 |
<0.0001 |
19 |
3.748 |
19.340 |
<0.0001 |
19 |
0.402 |
1.273 |
0.2270 |
Error |
75 |
506.1 |
74 |
0.194 |
75 |
0.316 |
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B) System level properties |
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Dissolved oxygen |
Sedimentation rate |
Total organic matter |
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Source |
df |
MS |
F |
P |
df |
MS |
F |
P |
df |
MS |
F |
P |
Species richness |
1 |
0.292 |
2.663 |
0.1069 |
1 |
0.486 |
1.452 |
0.2320 |
1 |
1.030 |
4.124 |
0.0459 |
Composition (SR) |
19 |
0.532 |
4.853 |
<0.0001 |
19 |
0.692 |
2.065 |
0.0142 |
19 |
0.714 |
2.859 |
0.0007 |
Error |
75 |
0.110 |
75 |
0.335 |
73 |
0.250 |
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