Ecological Archives A021-024-A2

Judith C. Klein, A. J. Underwood, and M. G. Chapman. 2011. Urban structures provide new insights into interactions among grazers and habitat. Ecological Applications 21:427–438.

Appendix B (TABLE B1). Survival of Patelloida in experiment 2 (see Fig. 3 for detailed data).

A) Analysis of proportional survival.

Source of variation df Mean Square F ratio P
Locations = L 1 0.11 4.4 < 0.05
Substrata = S 1 0.09 3.7 > 0.05
+/- Oysters = O 1 0.85 15.2 > 0.15 (see part b)
+/- Cellana = C 1 0.05 2.2 > 0.10
L × O 1 0.06 2.3 > 0.10
O × C 1 0.05 2.2 > 0.10
Residual 64 0.02    
All other Mean Squares for interactions were eliminated because P > 0.25

B) Outcome of multiple comparisons;  Means (SE); “=” indicates not significantly different;  s, n indicate significant and nonsignificant, respectively, from the corresponding treatment in the other location.  “+/- Oysters” was tested against the nonsignificant “L × O” MS, with only 1 and 1 df.  Given the large size of its MS (above) and lack of power of the test, multiple comparisons were done for L × O and for O × C, so that outcomes could be inferred to be presented exactly as in Table 1 for Experiment 1, which facilitates comparisons between the two experiments.

Locations (n = 40):   Cremorne Point:  0.84 (0.3) > Careening Cove:  0.77 (0.2)
     
L × O × C (n = 10)    

    - Cellana   + Cellana
Cremorne Point - Oysters 0.80n (0.04) 0.72s (0.05)
    ^   ^
  + Oysters 0.91n (0.02) = 0.92n (0.02)
Careening Cove - Oysters 0.70n (0.07) 0.57n (0.08)
    ^   ^
  + Oysters 0.90 n (0.03) = 0.89n (0.05)

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