TABLE 1.
Roles of environmental variables on α-diversity and copy numbers of the nirK and nirS genes evaluated by stepwise multivariate regression modeling
| Gene | α-Diversity/copy no. test | Explanatory variable | Contribution of the individual predictora (%) | P value | Adjusted R2 for full model (P value) |
|---|---|---|---|---|---|
| nirK | Chao 1 | pH | 13.1 | 0.001 | 0.20 (<0.0001) |
| DBH-DC | 7.2 | 0.050 | |||
| Observed OTUS | pH | 10.6 | 0.012 | 0.20 (<0.0001) | |
| DBH-DC | 9.5 | 0.024 | |||
| Copy no. | DBH-DB | 19.2 | 0.028 | 0.35 (<0.0001) | |
| TC/TN | 16.0 | 0.000 | |||
| nirS | Chao 1 | Plant richness | 30.1 | 0.000 | 0.40 (<0.0001) |
| NO3−-N | 9.9 | 0.002 | |||
| Observed OTUS | Plant richness | 15.9 | 0.000 | 0.23 (<0.0001) | |
| NO3−-N | 6.8 | 0.007 | |||
| MAT | 0.5 | 0.046 | |||
| Copy no. | TN | 21.3 | 0.001 | 0.51 (<0.0001) | |
| Plant richness | 17.4 | 0.008 | |||
| Cond | 7.5 | 0.008 | |||
| DBH-EB | 4.5 | 0.017 |
a
Percentage of the total sum of squares explained by each variable. DBH represents the total diameter at breast height, while DBH-DB, DBH-EB, and DBH-DC represent the percentage representation of deciduous broadleaf trees, evergreen broadleaf trees, and dark coniferous trees, respectively, in total DBH. TC, total carbon; TN, total nitrogen; MAT, mean annual temperature; Cond, Conductivity.