Appendix S1. Species from Mt. Franciscano and Mt. Tres Puntas. Species were classified according to the habitat type in which they were found. Cushions: species were only detected within Azorella monantha cushions; Open areas: species were only detected in unmodified open areas surrounding cushions; Both: species were detected in both habitat types. Absent indicates species not detected at a given mountaintop.

Species name (family name in brackets) / Mt. Franciscano / Mt. Tres Puntas
Acaena patagonica (Rosaceae) / Cushions / Absent
Adesmia sp. 1 (Fabaceae) / Both / Open areas
Adesmia sp. 2 (Fabaceae) / Open areas / Open areas
Barneoudia major (Ranunculaceae) / Both / Both
Bromus setifoluis (Poaceae) / Cushions / Cushions
Calandrinia affinis (Portulacaceae) / Cushions / Absent
Carex sp. 1 (Cyperaceae) / Both / Both
Carex sp. 2 (Cyperaceae) / Cushions / Absent
Cerastium arvense (Caryophyllaceae) / Cushions / Absent
Chaetanthera euphrasioides (Asteraceae) / Both / Open areas
Chaetanthera lycopodioides (Asteraceae) / Open areas / Absent
Chaetanthera pusilla (Asteraceae) / Absent / Open areas
Erigeron andicola (Asteraceae) / Both / Cushions
Festuca magellanica (Poaceae) / Cushions / Cushions
Hordeum comosum (Poaceae) / Both / Both
Loasa sigmoidea (Loasaceae) / Both / Cushions
Montiopsis potentilloides (Portulacaceae) / Open areas / Absent
Montiopsis andicola (Portulacaceae) / Absent / Cushions
Nassauvia lagascae (Asteraceae) / Open areas / Both
Nassauvia pyramidalis (Asteraceae) / Both / Open areas
Nastanthus agglomeratus (Calyceraceae) / Cushions / Cushions
Nototriche compacta (Malvaceae) / Absent / Open areas
Olsynium scirpoideum (Iridaceae) / Both / Absent
Oxalis compacta (Oxalidaceae) / Open areas / Open areas
Perezia carthamoides (Asteraceae) / Open areas / Absent
Perezia pilifera (Asteraceae) / Cushions / Absent
Phacelia secunda (Hydrophillaceae) / Both / Absent
Pozoa coriacea (Apiaceae) / Open areas / Open areas
Rytidosperma pictum (Poaceae) / Cushions / Cushions
Rytidosperma violaceum (Poaceae) / Both / Both
Senecio looseri (Asteraceae) / Both / Cushions
Taraxacum officinale (Asteraceae) / Both / Cushions
Thlaspi magellanicum (Brassicaceae) / Cushions / Cushions
Trisetum preslei (Poaceae) / Both / Both
Tropaeolum polyphyllum (Tropaeolaceae) / Open areas / Absent
Viola atropurpurea (Violaceae) / Open areas / Absent
Viola philippii (Violaceae) / Open areas / Absent
Total species number / 34 / 24