Data from: Climatic disequilibrium of recruit communities across a drought-induced die-off gradient in Mediterranean shrubland

Positive plant–plant interactions (facilitation) may enhance the
recruitment and establishment of species less adapted to local
macroclimatic conditions. A major cause of this effect is climatic
buffering, which implies an increased mismatch between the macroclimatic
conditions and the climatic requirements of the existing community –
climatic disequilibrium – of plants living under canopies. Here we explore
the effect of drought-induced defoliation of Mediterranean shrubland
canopy on the recruitment of woody species. We analyzed the differences in
the climatic disequilibrium across different categories of canopy
defoliation and plant–plant interactions: facilitation, neutral and
inhibition. Climatic disequilibrium was estimated as the Euclidean
distance in the multivariate environmental space between observed
macroclimate and community inferred climate. The inferred climate was
calculated by averaging the coordinates of the species’ climatic niche
centroids, obtained from species distribution, weighted by the
species' relative abundances in each community. We found that the
recruiting community growing under canopy showed higher climatic
disequilibrium than the community growing in the gaps. The facilitated
recruiting community growing under dead and living canopy showed the
highest disequilibrium, followed by the community growing under
mid-affected canopy. The climatic disequilibrium of the recruiting
communities experiencing neutral and inhibited interaction was not
affected by canopy defoliation. These findings indicate that the climatic
disequilibrium of the recruiting community is determined by the
facilitation–competition balance. Living canopy provides climatic
buffering, but it also implies competition, while dead canopy may provide
some structural climatic buffering, without implying competition for
resources. These results highlight the relevance of incorporating
plant–plant interactions, particularly facilitation, to better forecast
plant community responses to extreme climate events and climate change.