The terrestrial Arctic is often treated as a uniform biome of low biological diversity. It is true that species richness as well as the diversity of functional groups declines with increasing latitude within most organism groups (Matveyeva and Chernov 2000). However, trends in other less studied aspects of biological diversity, such as genetic diversity within species, might well turn out to be comparable to other biomes (Callaghan et al. 2004, The ACIA report 2005), at least on certain spatial scales.
When exploring patterns of diversity at different levels of biological organisation it is important to consider how they vary at different scales in time and space in relation to variability of the environmental factors that affect diversity. Typical for the Arctic is the overriding role of abiotic factors in shaping the environment experienced by the organisms in most habitats, and the large topographic impact on theses factors, thereby creating large environmental heterogeneity at various spatial scales (Jónsdóttir 2005).
The Svalbard Archipelago is situated in the High Arctic, extending across the three coldest bioclimatic sub-zones (termed zones hereafter) of the Arctic, termed A, B, and C (Elvebakk 1997, CAVM Team 2003). Due to its dramatic topography, large environmental contrasts are encountered across relatively short distances, which provide an ideal situation for demonstrating and studying terrestrial ecology in a variety of arctic settings. During the summer 2005, the University Centre in Svalbard (UNIS) organised a post-graduate course in arctic plant ecology (AB-326) where the students explored spatial heterogeneity of four different plant-ecological patterns in relation to environmental variables: vegetation differentiation, species richness, reproduction, and plant tissue chemical composition of common vascular plant species.
A separate scientific report was written on each of these four themes (for practical reasons there are two separate reports on reproduction) and the main findings will be summarised and discussed below. The unifying question for the project themes was whether these patterns were under stronger control of local environmental factors than of large or intermediate scale (regional) factors such as climate and bedrock. Large-scale temporal pattern, i.e. vegetation history, was also addressed in a literature survey by one of the students.
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