TABLE 3.
Results of MRPP testing for significant differences between predefined groups determined on the basis of nosZ T-RFLP profiles (CfoI, MspI, and RsaI results have been combined)
| Test and sites |
A statistica
|
|
|---|---|---|
| Difference in proportional abundance | Difference in presence vs absence | |
| Comparison by vegetation type | ||
| Carpenter meadow vs Carpenter forest | 0.29 (P < 10−5) | 0.23 (P < 10−5) |
| Lookout meadow vs Lookout forest | 0.26 (P < 10−5) | 0.34 (P < 10−5) |
| Comparison by site | ||
| Carpenter meadow vs Lookout meadow | 0.18 (P < 0.001) | 0.17 (P < 0.001) |
| Carpenter forest vs Lookout forest | 0.24 (P < 10−5) | 0.05 (P = 0.02) |
| Comparison of randomized datab | ||
| Carpenter meadow vs Carpenter forest | −0.04 (P = 1.0) | −0.01 (P = 0.7) |
a
The A statistic measures within-group relatedness compared to that expected by chance; A statistic values of about 0.3 reflect strong differences between groups (23).
b
T-RFLP profiles from the Carpenter site were randomized among sample units.