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Subalpine-nival gradient of species richness for vascular plants, bryophytes and lichens in the Swiss Inner Alps

Pascal Vittoz, Martin Camenisch, Romain Mayor, Luca Miserere, Mathias Vust, Jean-Paul Theurillat

Appendices(online supplement)

Appendix 1 Macroecological model for the decrease of the species richness with elevation according to the temperature-physiography hypothesis in the Alps (see text; Theurillat et al. 2003). At the biological level, temperature acts uniformly on the adapted species pool (biological filter) within a given region due to the adiabatic decrease of temperature. Factors at the geomorphological level and human use act as variable modulators on the species pool by influencing habitat diversity.

Appendix 2General description of the 12 inventoried summits in Switzerland. The chemistry of the rocks is below the region codes. Temperature was measured5 m below the summit for each aspect in VALs, but only on the summit point in SNs and SNc. The estimated areas and the number of species are indicated for the whole summit (in italics), for each summit section (5- and 10-m sections, together) and for each cluster of four 1x1-m quadrats (three clusters in VALs were not sampled).

Appendix 3 Total species richness on the entire summit (first line), in summit sections (second line) and in clusters of four 1x1-m quadrats for vascular plants in the three regions (left column) and for vascular plants, bryophytes and lichens in the VALs region (right column).

SNsr2=0.94p=0.031Vascular plantsr2=0.83p=0.089

SNcr2=0.99p=0.004Bryophytesr2=0.80p=0.103

VALsr2=0.83p=0.089Lichensr2=0.71p=0.158

Nr2=0.81p<0.001Vascular plantsr2=0.74p<0.001

Er2=0.70p<0.001Bryophytesr2=0.54p=0.001

Sr2=0.76p<0.001Lichensr2=0.67p<0.001

Wr2=0.67p=0.001

Nr2=0.64p=0.002Vascular plantsr2=0.68p<0.001

Er2=0.58p=0.004Bryophytesr2=0.03p=0.587

Sr2=0.65p=0.003Lichensr2=0.20p=0.121

Wr2=0.54p=0.016

Appendix 4 Result of a linear mixed model for the species richness in quadrats of the VALs region in relation to the altitude, systematic group and slope. The vascular plants were used as reference. Analysis was carried out with 39 observations and 4 groups.

Appendix 5Life forms of vascular plants in summit sections of the three regions in relation to the altitude. Chamaephytes, r2=0.67; hemicryptophytes, r2=0.49; geophytes, r2=0.40; all linear regressions are significant at p<0.001. Therophytes have a very similar distribution to geophytes.

Appendix 6Distribution of life forms of bryophytes and lichens in quadrats in the VALs region in relation to the altitude. Weft bryophytes and foliaceous lichens showed no significant trend and always had low abundance.

Cushionr2=0.57p=0.003Crustaceousr2=0.70p<0.001

Turfr2=0.51p=0.006Fruticoser2=0.75p<0.001

Matsr2=0.28p=0.061Squamulousr2=0.05p=0.472