Table 2.
Results of linear mixed effects models testing the effects of warming, drought, and their interaction on energy fluxes and biomass of the whole food web, microbes, total fauna, and the three faunal trophic groups (detritivores, predators, herbivores), on the relative contributions of microbes, detritivores, predators, and herbivores to whole food web energy flux as well as on the resilience of the whole food web in the warming × drought experiment. Significance of fixed effects was obtained by Wald chi-square tests. Significant effects (p < 0.05) are reported in bold. For models with significant (p < 0.05) and marginally significant (p < 0.1) interaction terms we performed post-hoc Tuckey´s HSD tests that are reported in Supplementary Table 6.
| Transformation | Warming | Drought | Warming x Drought | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| χ2 | df | p-value | χ2 | df | p-value | χ2 | df | p-value | ||
| Energy flux (g C m−2 d−1) | ||||||||||
| Whole food web | log10(x) | 5.622 | 1 | 0.018 | 15.438 | 1 | <0.001 | 7.892 | 1 | 0.005 |
| Microbes | log10(x) | 12.400 | 1 | <0.001 | 11.927 | 1 | 0.001 | 8.455 | 1 | 0.004 |
| Fauna | log10(x) | 9.054 | 1 | 0.003 | 1.016 | 1 | 0.313 | 0.593 | 1 | 0.441 |
| Detritivores | log10(x) | 8.935 | 1 | 0.003 | 0.111 | 1 | 0.739 | 0.055 | 1 | 0.814 |
| Predators | log10(x) | 1.249 | 1 | 0.264 | 1.208 | 1 | 0.272 | 0.038 | 1 | 0.846 |
| Herbivores | log10(x) | 2.814 | 1 | 0.093 | 0.162 | 1 | 0.688 | 1.355 | 1 | 0.244 |
| Biomass (g C m−2) | ||||||||||
| Whole food web | log10(x) | 0.811 | 1 | 0.368 | 0.164 | 1 | 0.686 | 6.048 | 1 | 0.014 |
| Microbes | log10(x) | 0.872 | 1 | 0.351 | 0.164 | 1 | 0.685 | 6.088 | 1 | 0.014 |
| Fauna | log10(x) | 1.421 | 1 | 0.233 | 0.191 | 1 | 0.662 | 0.200 | 1 | 0.654 |
| Detritivores | log10(x) | 0.001 | 1 | 0.979 | 1.039 | 1 | 0.308 | 0.583 | 1 | 0.445 |
| Predators | log10(x) | 0.059 | 1 | 0.808 | 0.000 | 1 | 0.984 | 0.032 | 1 | 0.857 |
| Herbivores | log10(x) | 0.762 | 1 | 0.383 | 0.054 | 1 | 0.817 | 6.177 | 1 | 0.013 |
| Relative energy flux (proportion) | ||||||||||
| Microbes | logit(x) | 11.359 | 1 | 0.001 | 0.277 | 1 | 0.599 | 1.104 | 1 | 0.293 |
| Detritivores | logit(x) | 15.457 | 1 | <0.001 | 0.676 | 1 | 0.411 | 1.147 | 1 | 0.284 |
| Predators | logit(x) | 1.074 | 1 | 0.300 | 1.025 | 1 | 0.311 | 0.013 | 1 | 0.910 |
| Herbivores | logit(x) | 2.545 | 1 | 0.111 | 0.095 | 1 | 0.758 | 1.297 | 1 | 0.255 |
| Resilience to perturbations | ||||||||||
| Whole food web | 0.098 | 1 | 0.754 | 0.685 | 1 | 0.408 | 1.299 | 1 | 0.254 | |