DOI: 10.5061/dryad.8gr16
title: Data from: Plant community composition and species richness in the High Arctic tundra: from the present to the future

description: Arctic plant communities are altered by climate changes. The magnitude of
 these alterations depends on whether species distributions are determined
 by macroclimatic conditions, by factors related to local topography, or by
 biotic interactions. Our current understanding of the relative importance
 of these conditions is limited due to the scarcity of studies, especially
 in the High Arctic. We investigated variations in vascular plant community
 composition and species richness based on 288 plots distributed on three
 sites along a coast-inland gradient in Northeast Greenland using a
 stratified random design. We used an information theoretic approach to
 determine whether variations in species richness were best explained by
 macroclimate, by factors related to local topography (including soil
 water) or by plant-plant interactions. Latent variable models were used to
 explain patterns in plant community composition. Species richness was
 mainly determined by variations in soil water content, which explained 35%
 of the variation, and to a minor degree by other variables related to
 topography. Species richness was not directly related to macroclimate.
 Latent variable models showed that 23.0% of the variation in community
 composition was explained by variables related to topography, while
 distance to the inland ice explained an additional 6.4 %. This indicates
 that some species are associated with environmental conditions found in
 only some parts of the coast–inland gradient. Inclusion of macroclimatic
 variation increased the model's explanatory power by 4.2%. Our
 results suggest that the main impact of climate changes in the High Arctic
 will be mediated by their influence on local soil water conditions.
 Increasing temperatures are likely to cause higher evaporation rates and
 alter the distribution of late-melting snow patches. This will have little
 impact on landscape-scale diversity if plants are able to redistribute
 locally to remain in areas with sufficient soil water.
description: Species presence in
 plotgroupsThe file “Nabe-Nielsen
 etal 2017 Young Sund spp pres in plotgrps” contains data on the number of
 plots where each vascular plant species was present within each of the 48
 plot groups. Species names are based on nomenclature in Supplementary
 Information in the published paper.Nabe-Nielsen etal 2017 Young
 Sund spp pres in plotgrps.csvVegetation cover and
 environmental data per plot groupThe file “Nabe-Nielsen
 etal 2017 Young Sund plotgroup data.csv” contains data on average
 vegetation cover, average number of plant species per plot and average
 environmental variables in each of 48 plot groups distributed along Young
 Sund, a High Arctic fjord in Northeast Greenland. The plots are located in
 three sites: “Zackenberg”, “Blæsedalen” and “Tyrolerfjord”. Each plot
 group consists of six plots. See the published paper for further details.
 Environemental variables include: altitude [m], continentality index [*],
 slope [degrees], solar radiation index [*], soil water [percent], and
 temperature [degrees celsius]. *See the paper for definitions of the
 indices.Nabe-Nielsen etal 2017 Young
 Sund plotgroup data.csv