Table 2 Year-to-year differences in control plots.

From: Vascular plant abundance and diversity in an alpine heath under observed and simulated global change

Response

group mean

Mean diff. from 1995

t-value

d.f.

p-value

Total cover

 1995

46.375

    

 1999

48.250

1.875

0.297

21

0.77

 2001

60.625

14.250

2.259

21

0.03

Shannon diversity index

 1995

1.399

    

 1999

1.163

−0.235

−1.345

21

0.19

 2001

1.258

−0.141

−0.804

21

0.43

Total species richness

 1995

6.750

    

 1999

5.875

−0.875

−0.946

21

0.36

 2001

6.750

0

0

21

1

  1. A priori orthogonal contrasts comparing group means of total cover, species richness and Shannon diversity in the eight control plots from 1995, the first year the plots were set up, to 1999 and 2001.
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