Data from: Food-web structure varies along environmental gradients in a high-latitude marine ecosystem

Large-scale patterns in species diversity and community composition are
associated with environmental gradients, but the implications of these
patterns for food-web structure are still unclear. Here, we investigated
how spatial patterns in food-web structure are associated with
environmental gradients in the Barents Sea, a highly productive shelf sea
of the Arctic Ocean. We compared food webs from 25 subregions in the
Barents Sea and examined spatial correlations among food-web metrics, and
between metrics and spatial variability in seawater temperature, bottom
depth and number of days with ice cover. Several food-web metrics were
positively associated with seawater temperature: connectance, level of
omnivory, clustering, cannibalism, and high variability in generalism,
while other food-web metrics such as modularity and vulnerability were
positively associated with sea ice and negatively with temperature.
Food-web metrics positively associated with habitat heterogeneity were:
number of species, link density, omnivory, path length, and trophic level.
This finding suggest that habitat heterogeneity promotes food-web
complexity in terms of number of species and link density. Our analyses
reveal that part of the variation in food-web structure along the
environmental gradients is related to species turnover, however the higher
interaction turnover compared to species turnover along these gradients
indicates a consistent modification of the food-web structure along
environmental gradients. This could indicate that interacting species
co-vary in space. In conclusion, our study shows how environmental
heterogeneity via environmental filtering, not only drives turnover in
species composition, but also how it influences the structure of food webs
over large spatial scales.