Data from: Drivers of plant community composition and species richness in Western Greenland

The Arctic experiences rapid climate change, but our ability to predict
how this will influence plant communities is hampered by a lack of data on
the extent to which different species are associated with particular
environmental conditions, how these conditions are interlinked, and how
they will change in coming years. Increasing temperatures may negatively
affect plants associated with cold areas due to increased competition with
warm-adapted species, but less so if local temperature variability is
larger than the expected increase. Here we studied the potential drivers
of vegetation composition and species richness along coast to inland and
altitudinal gradients by the Nuuk fjord in western Greenland using
Hierarchical Modelling of Species Communities (HMSC) and linear mixed
models. Community composition was more strongly associated with random
variability at intermediate spatial scales (among plot groups 500 m apart)
than with large-scale variability in summer temperature, altitude or soil
moisture, and the variation in community composition along the fjord was
small. Species richness was related to plant cover, altitude and slope
steepness, which explained 42% of the variation, but not to summer
temperature. Jointly, this suggests that the direct effect of climate
change will be weak, and that many species are associated with
microhabitat variability. However, species richness peaked at intermediate
cover, suggesting that an increase in plant cover under warming climatic
conditions may lead to decreasing plant diversity.