Supplementary material - Climate change will facilitate the establishment of potentially impactful plants on currently treeless sub-Antarctic islands

S1. Size (km2), jurisdiction or dependency, elevation (m) and established alien plant species of the 12 (sub)-Antarctic islands included in the study (Leihy et al., 2023).

S2. True-skill statistic (TSS), sensitivity, and specificity for each species and model.

S3. Plots of variable importance of all variables in the three models, averaged across all species.

S4. Value ranges of variables on the sub-Antarctic islands used in the three models. Derived from Karger et al., 2017.

S5. Projected percentages of suitable cells for all 2,220 species for recent climatic conditions and each GCM x scenario combination, with growth form information. Both uncorrected and corrected (with exclusion of cells outside the clamping mask) projections are provided for each of the variable sets.

S6. Projected percentages of suitable cells for all 2,220 species for recent climatic conditions and each GCM x scenario combination, with growth form information. Both uncorrected and corrected (with exclusion of cells outside the clamping mask) projections are provided. The percentages of cells for which each three variable sets agree on suitability are given (i.e. consensus projections).

S7. Projected percentages of suitable cells for species established on the respective (sub-)Antarctic islands for recent climatic conditions and each GCM x scenario combination, with growth form information. Both uncorrected and corrected (with exclusion of cells outside the clamping mask) projections are provided. The percentages of cells for which each three variable sets agree on suitability are given (i.e. consensus projections) (Leihy et al., 2023).

S8. Ratio of change in suitable cells, as compared to projections under recent climatic conditions, for each GCM and scenario combination. Ratios for both uncorrected and corrected (with exclusion of cells outside the clamping mask) projections are provided. Ratios of suitability are calculated as the amount of suitable cells, divided by the total cells. The ratio of change is subsequently calculated by subtracting the ratio of each GCM x scenario combination by the ratio of projections under recent climate.

S9. Results of the factorial ANOVA assessing the effects of General Circulation Model (GCM), climate change scenario, and species distribution model on predicted climate suitability for alien plant species in the sub-Antarctic. The analysis includes both corrected and uncorrected projections. Significant main effects and interactions are observed for all factors, with the strongest effect from model (i.e. variable set) choice.

S10. Count of growth forms projected on each of the islands, for each GCM and scenario combination. The ratio of woody to herbaceous species is provided.

S11. Plot showing the projected number of alien woody species on the islands, for each GCM and scenario combination.

S12. Estimated Marginal Means (EMM) of the GLMM for scenario and GCM, and their combinations.

S13. Contrasts of Estimated Marginal Means (EMM) of the GLMM between each GCM and scenarios, and their combinations.