Drought overrides CO2-driven carbon sink enhancement in Moroccan Atlas cedar forests

Increasing drought and extensive forest die-off may override the fertilization effect of rising atmospheric CO2 (Ca), limiting the contribution of forests as carbon sinks. Tree-rings-based estimates of intrinsic water use effi-ciency (iWUE) have been recently improved, including the effects of diffus...

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Autores: Crespo-Antia, Juan Pablo, Camarero, J. Julio, Sangüesa-Barreda, Gabriel, Lechuga, Víctor, Ochoa, Victoria, Linares Calderón, Juan Carlos
Tipo de documento: artigo
Data de publicação:2026
País:España
Recursos:Universidad Pablo de Olavide (UPO)
Repositório:RIO. Repositorio Institucional Olavide
Idioma:inglês
OAI Identifier:oai:dnet:rio_________::30a8b4c6c196bf536bbaabd3f45842f4
Acesso em linha:https://hdl.handle.net/10433/26567
Access Level:Acceso aberto
Palavra-chave:Basal area increment
Cedrus atlantica
CO2 fertilization
Drought stress
Intrinsic water use efficiency
Dendrochronology
Carbon isotopes
Carbon sink
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spelling Drought overrides CO2-driven carbon sink enhancement in Moroccan Atlas cedar forestsCrespo-Antia, Juan PabloCamarero, J. JulioSangüesa-Barreda, GabrielLechuga, VíctorOchoa, VictoriaLinares Calderón, Juan CarlosBasal area incrementCedrus atlanticaCO2 fertilizationDrought stressIntrinsic water use efficiencyDendrochronologyCarbon isotopesCarbon sinkIncreasing drought and extensive forest die-off may override the fertilization effect of rising atmospheric CO2 (Ca), limiting the contribution of forests as carbon sinks. Tree-rings-based estimates of intrinsic water use effi-ciency (iWUE) have been recently improved, including the effects of diffusion through stomata and mesophyll, carboxylation and photorespiration. However, it remains unclear whether increasing iWUE is attributable to carbon gain or water shortage. We tested whether leaf gas-exchange regulation, inferred from tree-ring δ13C, translates into actual growth or reflects drought responses. Wood δ13C and basal area increment were analysed to investigate the effect of rising Ca and drought stress on growth and iWUE of Atlas cedar (Cedrus atlantica) forests, spanning seven centuries across a latitudinal gradient in Morocco. iWUE remained stable (~50 μmol CO₂ mol⁻¹ H₂O) across sites until the onset of the 20th century, whereas long-term growth showed greater variability. Since the 1980s, sequential increases in drought sensitivity and growth decline were observed, starting by the southernmost dry regions but extending northwards. Nonetheless, iWUE maintained rising trends, with an average Ci/Ca ratio of 0.72 and Ca sensitivity of 0.18 ppm ppm-1. Growth and iWUE became increasingly decoupled in southern populations, suggesting that rising Ca no longer enhances growth under intensified drought. Local extinction risk is expected to increase at the High Atlas (trailing edge), while the highest con-servation priority must be in the Rif (leading edge). We conclude that, whereas Ca and drought have synergistic effects on iWUE, increasing VPD and decreasing soil water availability prevail as drivers of the progressive decoupling between growth and iWUE.Elsevier20262026-05-1220262026-05-0820262026-05-08journal articlehttp://purl.org/coar/resource_type/c_6501VoRhttp://purl.org/coar/version/c_970fb48d4fbd8a85info:eu-repo/semantics/articleapplication/pdfhttps://hdl.handle.net/10433/26567reponame:RIO. Repositorio Institucional Olavideinstname:Universidad Pablo de Olavide (UPO)Inglésengopen accesshttp://purl.org/coar/access_right/c_abf2Attribution-NonCommercial-NoDerivatives 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-nd/4.0/info:eu-repo/semantics/openAccessoai:dnet:rio_________::30a8b4c6c196bf536bbaabd3f45842f42026-06-13T12:46:27Z
dc.title.none.fl_str_mv Drought overrides CO2-driven carbon sink enhancement in Moroccan Atlas cedar forests
title Drought overrides CO2-driven carbon sink enhancement in Moroccan Atlas cedar forests
spellingShingle Drought overrides CO2-driven carbon sink enhancement in Moroccan Atlas cedar forests
Crespo-Antia, Juan Pablo
Basal area increment
Cedrus atlantica
CO2 fertilization
Drought stress
Intrinsic water use efficiency
Dendrochronology
Carbon isotopes
Carbon sink
title_short Drought overrides CO2-driven carbon sink enhancement in Moroccan Atlas cedar forests
title_full Drought overrides CO2-driven carbon sink enhancement in Moroccan Atlas cedar forests
title_fullStr Drought overrides CO2-driven carbon sink enhancement in Moroccan Atlas cedar forests
title_full_unstemmed Drought overrides CO2-driven carbon sink enhancement in Moroccan Atlas cedar forests
title_sort Drought overrides CO2-driven carbon sink enhancement in Moroccan Atlas cedar forests
dc.creator.none.fl_str_mv Crespo-Antia, Juan Pablo
Camarero, J. Julio
Sangüesa-Barreda, Gabriel
Lechuga, Víctor
Ochoa, Victoria
Linares Calderón, Juan Carlos
author Crespo-Antia, Juan Pablo
author_facet Crespo-Antia, Juan Pablo
Camarero, J. Julio
Sangüesa-Barreda, Gabriel
Lechuga, Víctor
Ochoa, Victoria
Linares Calderón, Juan Carlos
author_role author
author2 Camarero, J. Julio
Sangüesa-Barreda, Gabriel
Lechuga, Víctor
Ochoa, Victoria
Linares Calderón, Juan Carlos
author2_role author
author
author
author
author
dc.contributor.none.fl_str_mv
dc.subject.none.fl_str_mv Basal area increment
Cedrus atlantica
CO2 fertilization
Drought stress
Intrinsic water use efficiency
Dendrochronology
Carbon isotopes
Carbon sink
topic Basal area increment
Cedrus atlantica
CO2 fertilization
Drought stress
Intrinsic water use efficiency
Dendrochronology
Carbon isotopes
Carbon sink
description Increasing drought and extensive forest die-off may override the fertilization effect of rising atmospheric CO2 (Ca), limiting the contribution of forests as carbon sinks. Tree-rings-based estimates of intrinsic water use effi-ciency (iWUE) have been recently improved, including the effects of diffusion through stomata and mesophyll, carboxylation and photorespiration. However, it remains unclear whether increasing iWUE is attributable to carbon gain or water shortage. We tested whether leaf gas-exchange regulation, inferred from tree-ring δ13C, translates into actual growth or reflects drought responses. Wood δ13C and basal area increment were analysed to investigate the effect of rising Ca and drought stress on growth and iWUE of Atlas cedar (Cedrus atlantica) forests, spanning seven centuries across a latitudinal gradient in Morocco. iWUE remained stable (~50 μmol CO₂ mol⁻¹ H₂O) across sites until the onset of the 20th century, whereas long-term growth showed greater variability. Since the 1980s, sequential increases in drought sensitivity and growth decline were observed, starting by the southernmost dry regions but extending northwards. Nonetheless, iWUE maintained rising trends, with an average Ci/Ca ratio of 0.72 and Ca sensitivity of 0.18 ppm ppm-1. Growth and iWUE became increasingly decoupled in southern populations, suggesting that rising Ca no longer enhances growth under intensified drought. Local extinction risk is expected to increase at the High Atlas (trailing edge), while the highest con-servation priority must be in the Rif (leading edge). We conclude that, whereas Ca and drought have synergistic effects on iWUE, increasing VPD and decreasing soil water availability prevail as drivers of the progressive decoupling between growth and iWUE.
publishDate 2026
dc.date.none.fl_str_mv 2026
2026-05-12
2026
2026-05-08
2026
2026-05-08
dc.type.none.fl_str_mv journal article
http://purl.org/coar/resource_type/c_6501
VoR
http://purl.org/coar/version/c_970fb48d4fbd8a85
dc.type.openaire.fl_str_mv info:eu-repo/semantics/article
format article
dc.identifier.none.fl_str_mv https://hdl.handle.net/10433/26567
url https://hdl.handle.net/10433/26567
dc.language.none.fl_str_mv Inglés
eng
language_invalid_str_mv Inglés
language eng
dc.rights.none.fl_str_mv open access
http://purl.org/coar/access_right/c_abf2
Attribution-NonCommercial-NoDerivatives 4.0 International
http://creativecommons.org/licenses/by-nc-nd/4.0/
dc.rights.openaire.fl_str_mv info:eu-repo/semantics/openAccess
rights_invalid_str_mv open access
http://purl.org/coar/access_right/c_abf2
Attribution-NonCommercial-NoDerivatives 4.0 International
http://creativecommons.org/licenses/by-nc-nd/4.0/
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv Elsevier
publisher.none.fl_str_mv Elsevier
dc.source.none.fl_str_mv reponame:RIO. Repositorio Institucional Olavide
instname:Universidad Pablo de Olavide (UPO)
instname_str Universidad Pablo de Olavide (UPO)
reponame_str RIO. Repositorio Institucional Olavide
collection RIO. Repositorio Institucional Olavide
repository.name.fl_str_mv
repository.mail.fl_str_mv
_version_ 1869406612116996096
score 15,228081

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