Changes in arctic vegetation on Jan Mayen Island over 19 and 80 years

• Published in: Journal of Vegetation Science
• Main Authors: Kapfer, Jutta, Virtanen, Risto, Grytnes, John‐Arvid
• Other Authors: Cousins, Sara
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2012
• Subjects: Arctic; Jan Mayen; Climate change; Jan Mayen Island
• Online Access: http://dx.doi.org/10.1111/j.1654-1103.2012.01395.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1654-1103.2012.01395.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1654-1103.2012.01395.x

Abstract Questions Can recent vegetation changes on an isolated, grazer‐free island be explained by recent climate change? Are observed changes consistent when focusing on two different time scales? Location J an M ayen, an a rctic volcanic island in the N orth A tlantic O cean. Methods We re‐surveyed two botanical studies conducted 19 and 80 yr earlier to explore changes in species frequency, cover and co‐occurrence with other species. The observed changes were statistically evaluated using restricted permutation tests and were compared for the two time scales considered using P earson correlation tests. Results Total number of species did not significantly change over the two time periods considered. One species ( B otrychium lunaria ) was found new to the island. The dwarf‐shrub S alix herbacea and several graminoids increased in frequency or cover, or both, whereas species linked to snowbeds (e.g. S axifraga spp., O xyria digyna , C erastium cerastoides ) decreased. Changes over 19 yr were significantly correlated with 80‐yr changes considering species frequency, but not when comparing changes in cover and species co‐occurrences. Observed changes were more pronounced in the 80‐yr comparison. Conclusions Our findings from the virtually grazer‐free island of J an M ayen are in line with other studies on short‐ and long‐term vegetation changes in the A rctic and confirm that indirect effects of climate change (e.g. longer growing season, altered soil moisture conditions, increased nutrient availability) may be the main driver of the observed changes in arctic vegetation composition. However, whereas our study found the main trend to be similar over both time scales considered, discrepancies in the trends of some species suggest that long‐term changes are only partly predictable from short‐term studies.