Arctic plant ecology: From tundra to polar desert in Svalbard - Unis

distribution. The complete results for the ecological amplitudes of 67 species on
Svalbard are found in Appendix 1.
As can be seen in Table 4, the smallest group consists of plants with the widest
amplitude in pH range, most of them with a northernmost occurrence in bioclimatic
zone A.
Twenty­eight species show a medium range for pH values medium to high whereas
only one plant, Luzula confusa, has a medium range for pH levels from low to
medium. The emphasis of the distribution limit focuses on the northernmost
bioclimatic zone A.
No taxon can be found for the group with narrow range and low pH. Twenty­one
species show a narrow range for medium pH. Thirteen taxa are found in the group
with preferences for high pH only. In all groups a tendency can be seen that the
category including most taxa for a given pH range displays its northernmost main
distribution limit in bioclimatic zone A.
Figure 3. CA ordination of hits per species (67 in total) in 88 plots, located on Svalbard, in
relation to environmental variables. Stars indicate significant variables. Sample and
species labels were omitted in the figure. First and second axis explained 7.8% and
7%, respectively.
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