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

Biodiversity in the High Arctic: species richness at
selected sites in Svalbard, 78­80°N
Henrik Antonsson 1 , Marte Holten Jørgensen 2 , and Ane Christensen Tange 3
1 Department of Plant and Environmental Sciences, Göteborg University. Box 460 S­405 30 Göteborg,
Sweden. E­mail: henrik.antonsson@dpes.gu.se. 2 Program for Molecular Ecology and Biosystematics,
Department of Biology, University of Oslo, P.O. Box 1066 Blindern, NO­0316 Oslo, Norway.
3 Department of Biology, Norwegian University of Science and Technology, NTNU NO­7491
Trondheim, Norway.
Abstract
Biodiversity is today greatly endangered by human activities, particularly in the
vulnerable Arctic. We studied 15 plant communities in the arctic archipelago of
Svalbard (78­80°N) distributed in three different bioclimatic zones in search for
differences in species richness, and causes for these. We recorded biodiversity as point
frame interceptions (0.25 m 2 ; 25 points), species present in frames, and species lists
for each site visited, and compared them with major environmental factors; soil
temperature, soil moisture, soil pH, exposure, slope angle, bioclimatic zones, and
productivity. The resulting dataset was analysed using Kruskal­Wallis tests, Kendall’s
τ correlations, ANOVA and ordination methods (PCA and RDA). Our results suggest
that: species diversity, on a landscape as well as local scale, decreases in relation to
bioclimatic zones (from C to A). Ordination methods implied that species richness is
correlated with bioclimatic zones, soil temperature, production and ground cover. We
conclude that biodiversity in the Arctic is highly scale­dependent and that this model
needs more testing, in order for policymakers to make wise decisions on conservation
of Arctic environments.
Keywords: Arctic, bioclimatic zones, biodiversity, plants, species richness, Svalbard
Introduction
Human activities are reducing the number of species worldwide at a rapid pace with
potentially devastating effects on ecosystem services, and in the long run economical
and social consequences (Hooper et al. 2005). Climate changes induce migration of
species, loss of some species, replacement of some and arrival of invading species into
plant communities. Proof for this pattern has been published from numerous sites
along the tundra and the Arctic, from experimental warning experiments (Walker et
al.2006), as well as real changes in vegetation (Kullman 2000, Truong 2003). This
may cause large­scale changes in community composition, which surely will have a
detrimental effect on arctic and alpine ecosystems. Concerns for loss of biodiversity
are raised throughout the world and investigations on what factors are most important
in determining biodiversity are heavily debated in the scientific community. Increasing
our knowledge on this issue is not merely of academic interest, but of great importance
in order to predict short and long­term effects of climate change on arctic tundra.
The first general model concerning what determines plant diversity was developed by
Grime (1973). His humpback or intermediate disturbance model of plant species
density predicted that species richness is depending on level of stress and production.
Following Grime, a large number of studies on this topic have been published, most of
11