Vegetation on mesic loamy and sandy soils along a 1700-km maritime Eurasia Arctic Transect

Questions How do plant communities on zonal loamy vs. sandy soils vary across the full maritime Arctic bioclimate gradient? How are plant communities of these areas related to existing vegetation units of the European Vegetation Classification? What are the main environmental factors controlling the transitions of vegetation along the bioclimate gradient? Location 1700‐km Eurasia Arctic Transect (EAT), Yamal Peninsula and Franz Josef Land (FJL), Russia. Methods The Braun‐Blanquet approach was used to sample mesic loamy and sandy plots at 14 total study sites at six locations, one in each of the five Arctic bioclimate subzones and the forest‐tundra transition. Trends in soil factors, cover of plant growth forms (PGFs), and species diversity were examined along the summer‐warmth‐index (SWI) gradient and on loamy and sandy soils. Classification and ordination were used to group the plots and to test relationships between vegetation and environmental factors. Results Clear, mostly nonlinear, trends occurred for soil factors, vegetation‐structure, and species diversity along the climate gradient. Cluster analysis revealed seven groups with clear relationships to subzone and soil texture. Clusters at the ends of the bioclimate gradient (forest‐tundra and polar desert) had many highly diagnostic taxa, whereas clusters from the Yamal Peninsula had only a few. Axis 1 of a Detrended Correspondence Analysis was strongly correlated with latitude and summer warmth; Axis 2 was strongly correlated with soil moisture, percentage sand, and landscape age. Conclusions Summer temperature and soil texture have clear effects on tundra canopy structure and species composition, with consequences to ecosystem properties. Each layer of the plant canopy has a distinct region of peak abundance along the bioclimate gradient. The major vegetation types are weakly aligned with described classes of the European Vegetation Checklist indicating a continuous floristic gradient rather than distinct subzone regions. The study provides ground‐based vegetation data for satellite‐based interpretations of the western maritime Eurasian Arctic, and the first vegetation data from Hayes Island, Franz Josef Land, which is strongly separated geographically and floristically from the rest of the gradient and most susceptible to ongoing climate change. This article is protected by copyright. All rights reserved.