Data from: Stressor fluxes alter the relationship between beta-diversity and regional productivity

Dispersal of organisms can influence the relationship between
beta-diversity and regional productivity in heterogeneous environments.
However, many ecosystems are also linked by fluxes of stressors, with an
unknown influence on this relationship. In this study, we assess the
relationship between beta-diversity (measured as Bray-Curtis
dissimilarity) and regional productivity (measured as biovolume) under
various levels of a stressor flux in meta-ecosystems that were composed of
two marine micro-algae communities. We created heterogeneity by exposing
one of the two communities to a herbicide and manipulated regional
diversity by applying a dispersal gradient, which decreased
beta-diversity. We applied four stressor flux levels, which homogenized
the herbicide concentration between the communities over time. The
stressor flux changed the relationship between beta-diversity and regional
productivity by changing the effect of dispersal on regional productivity.
In absence of the stressor flux, the relationship between beta-diversity
and regional productivity was mostly not significant, but positive at the
end of the experiment. This positive relationship was generated by a
negative effect of dispersal on regional productivity, probably because
dispersal disrupted local dynamics by removing organisms from the
most-productive unstressed community. In presence of the stressor flux,
the relationship between beta-diversity and regional productivity was
often negative as dispersal now increased regional productivity. Dispersal
increased regional productivity by increasing the productivity of the
stressed community. This positive effect was stronger in the presence than
in the absence of the stressor flux because the stressor flux reduced the
concentration of the herbicide in the stressed community, where it
facilitated recovery. Our study shows that stressor fluxes can strongly
interact with the effects of dispersal on productivity and thus influence
diversity-productivity relationships.