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The legacy of water deficit on populations having experienced negative hydraulic safety margin
Author(s) -
Benito Garzón Marta,
González Muñoz Noelia,
Wigneron JeanPierre,
Moisy Christophe,
FernándezManjarrés Juan,
Delzon Sylvain
Publication year - 2018
Publication title -
global ecology and biogeography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.164
H-Index - 152
eISSN - 1466-8238
pISSN - 1466-822X
DOI - 10.1111/geb.12701
Subject(s) - ecology , environmental science , competition (biology) , population , hydrology (agriculture) , biology , geology , demography , geotechnical engineering , sociology
Aim The aim was to examine whether recent mortality can be explained by hydraulic failure linked to water deficit. Location Western Europe. Time period 1986–2014. Major taxa studied Forty‐four tree species. Methods We modelled the hydraulic safety margin (HSM) across the ranges of 44 tree species at their driest margin ( n = 193,261 plots), defined as the difference between the estimated minimal soil water potential of each plot and the species water stress threshold, which corresponds to the hydraulic failure of the vascular system. Soil water potential was estimated by applying Campbell's equations on the minimal and maximal soil water contents estimated from 1979 to 2010 in the top 289 cm of soil and five soil textures across the species ranges. For each species, we modelled the amount of average mortality derived from plots of the Spanish and French National Forest Inventories to the variation in modelled hydraulic safety margin and environmental drivers across the species ranges using hurdle models. Results We did not identify any global convergence of modelled HSM within the species distribution ranges, finding instead a rather large variability in modelled HSM for most of the studied species. Fifteen species, out of 25 for which the models were practicable, showed significantly higher mortality in populations with negative HSM in comparison to those showing positive HSM, with positive and negative interaction along the aridity index. Main conclusions The combination of competition, average climate and modelled HSM explained average tree mortality. Most of the species presented at least one population that had already experienced a negative HSM and many other populations a positive but narrow HSM, suggesting that climate change is likely to push some populations towards a higher risk of hydraulic failure in the drier conditions projected for Western Europe.