Ecological Archives E085-090-A2

Jennifer L. Burnaford. 2004. Habitat modification and refuge from sublethal stress drive a marine plant–herbivore association. Ecology 85:2837–2849.

Appendix B. Results of repeated-measures ANOVA on the effects of birds and shade on the abundance of Katharina under experimental devices.

Source of variation

df SS  MS  F P
           
Between Subjects (average effect over time)          

     Treatment

2 6.63 3.31 4.85

0.04

     Block 4 9.29 2.32 3.40
0.07
     Error 8 5.47 0.68  
 
  contrasts         
 
     Birds        [-H +B -S (EC) vs.  -H -B -S] 1 0.21 0.21 0.31
0.59
     Shade       [-H -B -S           vs. -H -B +S] 1 3.86 3.86 5.34
0.045
         
 
Within Subjects (change in effect over time)        
 
     Time 4 5.31 1.33 6.92
0.0004
     Time × Treatment 8 12.4 1.56 8.11
< 0.0001
     Time × Block 16 2.10 0.13 0.68

0.79

     Error 32 6.14 0.19  
 
  contrasts        
 
     Time × bird effect 4 0.84 0.21 1.09

0.38

     Time × shade effect 4 9.00 2.25 11.73
< 0.0001

   Notes: Treatments are coded by the presence or absence of Hedophyllum (+ or -H), Bird access (+ or -B) and Shade (+ or -S). Control treatments are coded by the presence or absence of devices (Exclusion Controls = EC). Abundances were calculated for five periods: Summer 1998 (average of May, June, July, August), November 1998, Summer 1999, November 1999 and Summer 2000. Data were square-root transformed prior to analysis.  As Mauchly’s criterion for homogeneity of variance-covariance matrices was nearly met (P = 0.03), P values from univariate analyses are presented with Huynh-Feldt adjusted probabilities. P values which are relevant to tested hypotheses and significant at the alpha = 0.05 level are in boldface type. 



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