TABLE 1.
The effect, p‐values, marginal, and conditional R 2 for linear mixed‐effect models testing the effect of drought, nitrogen addition, combined effect of drought and nitrogen addition, and the presence of an invasive plant on the shoot, root biomass, and plant functional traits (Hmax, SLA, LDMC, Nmass, SRL, and root diameter).
| Variable | Effect | p | Marginal R 2 | Conditional R 2 |
|---|---|---|---|---|
| Root biomass | ||||
| (Intercept) | + | <.001 | .78 | .78 |
| Drought | − | <.001 | ||
| Drought + N | − | <.001 | ||
| N | + | <.001 | ||
| Invasive | + | .3535 | ||
| Drought × Invasive | + | <.001 | ||
| Drought + N × Invasive | + | <.001 | ||
| N × Invasive | + | .9738 | ||
| Shoot biomass | ||||
| (Intercept) | + | <.001 | .91 | .92 |
| Drought | − | <.001 | ||
| Drought + N | + | .034 | ||
| N | + | <.001 | ||
| Invasive | + | .007 | ||
| Drought × Invasive | + | <.001 | ||
| Drought + N × Invasive | + | <.001 | ||
| N × Invasive | − | .498 | ||
| Hmax | ||||
| (Intercept) | + | <.001 | .76 | .76 |
| Drought | − | <.001 | ||
| Drought + N | − | .295 | ||
| N | + | <.001 | ||
| Invasive | + | .019 | ||
| Drought × Invasive | + | <.001 | ||
| Drought + N × Invasive | + | <.001 | ||
| N × Invasive | − | .411 | ||
| SLA | ||||
| (Intercept) | + | <.001 | .85 | .86 |
| Drought | + | <.001 | ||
| Drought + N | + | <.001 | ||
| N | + | <.001 | ||
| Invasive | + | .150 | ||
| Drought × Invasive | + | <.001 | ||
| Drought + N × Invasive | + | <.001 | ||
| N × Invasive | + | .233 | ||
| LDMC | ||||
| (Intercept) | + | <.001 | .80 | .79 |
| Drought | − | <.001 | ||
| Drought + N | − | <.001 | ||
| N | − | <.001 | ||
| Invasive | + | .280 | ||
| Drought × Invasive | − | <.001 | ||
| Drought + N × Invasive | − | <.001 | ||
| N × Invasive | − | .003 | ||
| N | ||||
| (Intercept) | + | <.001 | .85 | .85 |
| Drought | + | <.001 | ||
| Drought + N | + | <.001 | ||
| N | + | <.001 | ||
| Invasive | − | .735 | ||
| Drought × Invasive | + | <.001 | ||
| Drought + N × Invasive | + | <.001 | ||
| N × Invasive | − | .973 | ||
| SRL | ||||
| (Intercept) | + | <.001 | .95 | .95 |
| Drought | − | <.001 | ||
| Drought + N | − | <.001 | ||
| N | − | <.001 | ||
| Invasive | + | <.001 | ||
| Drought × Invasive | + | <.001 | ||
| Drought + N × Invasive | + | <.001 | ||
| N × Invasive | − | <.001 | ||
| Root diameter | ||||
| (Intercept) | + | <.001 | .93 | .93 |
| Drought | + | .256 | ||
| Drought + N | + | <.001 | ||
| N | + | <.001 | ||
| Invasive | + | .182 | ||
| Drought × Invasive | + | <.001 | ||
| Drought + N × Invasive | + | <.001 | ||
| N × Invasive | − | .737 | ||
Note: Statistically significant variables are indicated in bold.