How to cope with drought and not die trying: Drought acclimation across tree species with contrasting niche breadth

Abstract Worldwide drought events have been reported to cause tree growth decline and mortality, thus altering the carbon (C) balance of forest ecosystems. While most of the attention has been focused on the physiological mechanisms associated with drought‐induced tree responses of a few species at specific locations, the ecological attributes of these species, like their niche breadth, may be also important in determining species’ sensitivity or resilience to drought. We postulated that wide‐niche breadth tree species should be more drought‐resilient than narrow‐niche breadth species. Using the most severe 2015–2016 El Niño drought event in the last 70 years in Patagonia, we determined pre‐ and post‐drought growth (BAI, basal area increment), C reserves in the form of non‐structural carbohydrate concentrations (NSCs = starch and soluble sugars), wood isotope (δ 13 C, iWUE and δ 18 O) signalling and xylem anatomy (mean vessel diameter, mvd ) in eight angiosperm tree species of contrasting niche breadth across a sharp precipitation gradient in southern Chile. All species responded in unison after the drought with a non‐water‐conservative response, maintaining BAI and NSCs, decreasing δ 13 C, and increasing both mvd and the soluble sugars:NSCs ratio relative to pre‐drought time. Contrary to previous results reporting species‐specific drought responses, our results show unequivocally a functional coordination of organisms’ vital traits associated with a non‐water‐conservative strategy, and a drought‐induced acclimation based on starch conversion into soluble sugars in all of the tree species we examined, regardless of their niche breadth and habitat preference. We state that abiotic drivers such as drought may have selected similar interspecific responses provided that they operate at the community level rather than at the species level. These findings mark the need to revise current views about the ultimate interspecific functional coordination of organisms’ vital traits when facing more frequent and intensive drought events. A free Plain Language Summary can be found within the Supporting Information of this article.