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

details see Crawley 2002). The PCA, RDA and ANOVA analysis were performed
using site means in order to include the total species list.
Results
Species richness, species density and total species list are summarised in Figure 2, and
complete lists are in Appendix 1. We found 25, 32, and 49 species in total in zones A,
B, and C, respectively. More species were registered using presence/absence in frame
(species richness) as measure, than the point frame hits (species density) in all sites
(Figure 2). The Kruskal­Wallis test gave no significant results when grouping the
species richness per frame according to bioclimatic zones (H=5.039; Hc=5.11;
p=0.0805). Species richness was, however, significantly different among sites
(H=30.48; Hc=30.91; p=0.0066).
Figure 2. Summary of species data. Box plot of species density, species richness and total
species lists grouped according to bioclimatic zones.
Kendall’s τ correlations are given in Table 2. The only biodiversity measure
significantly correlated with any environmental factors, was species density which was
positively correlated with bioclimatic zones, meaning that the number of species
decreases going from zone C to B to A, and negatively correlated with latitude.
The UPGMA analysis clustered the sites more or less according to bioclimatic zones
and vegetation types (not shown). The sites from zone A and B were clustered
together and included also a small cluster with zone C (the heath sites 1607/1/1 and
2107/1/3, and the calcareous fen site 1607/1/2), whereas the remaining sites from zone
C clustered together; the species rich sites in Colesdalen (2207) and the birdcliff site in
Ossian Sarsfjellet.
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