Drought reduces tree growing season lenght but increases nitrogen resorption efficiency in a Mediterranean ecosystem

Detalhes bibliográficos
Autor(a) principal: Lobo Do Vale, Raquel
Data de Publicação: 2019
Outros Autores: Besson, Cathy Kurz, Caldeira, Maria, Chaves, Maria Manuela, Pereira, João Santos
Tipo de documento: Artigo
Idioma: por
Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
Texto Completo: http://hdl.handle.net/10400.5/17726
Resumo: Mediterranean ecosystems are hotspots for climate change, as the highest impacts are forecasted for the Mediterranean region, mainly by more frequent and intense severe droughts. Plant phenology is a good indicator of species’ responses to climate change. In this study, we compared the spring phenology of cork oak trees (Quercus suber), an evergreen species, over 2 contrasting years, a mild year (2004) and a dry year (2005), which was the most severe drought since records exist. We evaluated the timing of occurrence, duration, and intensity of bud development, budburst, shoot elongation, trunk growth, and leaf senescence (phenophases) and assessed the nitrogen resorption efficiency from senescent to green leaves. The temperature was the main driver of budburst. Nevertheless, water had the main role of constraining all the other phenophases by strongly reducing the growing season length (48 %) and consequently the tree growth. Basal area increment was the most affected growth variable (36 %), although it occurred at a similar rate in the 2 years. Shoot elongation was also reduced (21 %), yet elongation occurred at a higher rate in the dry year compared to the mild year. Leaf senescence during the bulk period was higher in the dry year, in which leaves were shed at the same rate over a longer period. Nitrogen concentrations in green and senescent leaves were affected by drought and nitrogen resorption efficiency increased remarkably (C22 %). Our results highlight the importance of studying different phenological metrics to improve our understanding of the ecosystem’s responses to climate change. The faster dynamics observed in shoot elongation, while all other phenophases developed at the same rate, indicate that leaf area development is privileged in cork oak. Water availability was the main driver of spring growth in this Mediterranean ecosystem; however, growth may be affected by complex interplays between precipitation and temperature, such as higher temperatures during dry winters or heatwaves during spring, that are likely to result in water stress. Longer studies are needed to disentangle those interplays. Finally, a higher nitrogen resorption efficiency in response to drought appears to be an adaptive trait that mitigates the limitation in nitrogen uptake by the roots during drought and contributes to improving tree fitness in the short term but will probably exert a negative feedback on the nitrogen cycle in the long term, which might affect the ecosystem functioning under the forecasted droughts
id RCAP_0aa1f20886038e045ca294264ad82af1
oai_identifier_str oai:repositorio.ul.pt:10400.5/17726
network_acronym_str RCAP
network_name_str Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
repository_id_str 7160
spelling Drought reduces tree growing season lenght but increases nitrogen resorption efficiency in a Mediterranean ecosystemdroughttree growingnitrogenMediterranean ecosystemMediterranean ecosystems are hotspots for climate change, as the highest impacts are forecasted for the Mediterranean region, mainly by more frequent and intense severe droughts. Plant phenology is a good indicator of species’ responses to climate change. In this study, we compared the spring phenology of cork oak trees (Quercus suber), an evergreen species, over 2 contrasting years, a mild year (2004) and a dry year (2005), which was the most severe drought since records exist. We evaluated the timing of occurrence, duration, and intensity of bud development, budburst, shoot elongation, trunk growth, and leaf senescence (phenophases) and assessed the nitrogen resorption efficiency from senescent to green leaves. The temperature was the main driver of budburst. Nevertheless, water had the main role of constraining all the other phenophases by strongly reducing the growing season length (48 %) and consequently the tree growth. Basal area increment was the most affected growth variable (36 %), although it occurred at a similar rate in the 2 years. Shoot elongation was also reduced (21 %), yet elongation occurred at a higher rate in the dry year compared to the mild year. Leaf senescence during the bulk period was higher in the dry year, in which leaves were shed at the same rate over a longer period. Nitrogen concentrations in green and senescent leaves were affected by drought and nitrogen resorption efficiency increased remarkably (C22 %). Our results highlight the importance of studying different phenological metrics to improve our understanding of the ecosystem’s responses to climate change. The faster dynamics observed in shoot elongation, while all other phenophases developed at the same rate, indicate that leaf area development is privileged in cork oak. Water availability was the main driver of spring growth in this Mediterranean ecosystem; however, growth may be affected by complex interplays between precipitation and temperature, such as higher temperatures during dry winters or heatwaves during spring, that are likely to result in water stress. Longer studies are needed to disentangle those interplays. Finally, a higher nitrogen resorption efficiency in response to drought appears to be an adaptive trait that mitigates the limitation in nitrogen uptake by the roots during drought and contributes to improving tree fitness in the short term but will probably exert a negative feedback on the nitrogen cycle in the long term, which might affect the ecosystem functioning under the forecasted droughtsEuropean Geosciences UnionRepositório da Universidade de LisboaLobo Do Vale, RaquelBesson, Cathy KurzCaldeira, MariaChaves, Maria ManuelaPereira, João Santos2019-04-11T10:14:07Z20192019-01-01T00:00:00Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articleapplication/pdfapplication/pdfhttp://hdl.handle.net/10400.5/17726porBiogeosciences, 16, 1265–1279, 2019https://doi.org/10.5194/bg-16-1265-2019info:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2024-11-20T19:03:42Zoai:repositorio.ul.pt:10400.5/17726Portal AgregadorONGhttps://www.rcaap.pt/oai/openairemluisa.alvim@gmail.comopendoar:71602024-11-20T19:03:42Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse
dc.title.none.fl_str_mv Drought reduces tree growing season lenght but increases nitrogen resorption efficiency in a Mediterranean ecosystem
title Drought reduces tree growing season lenght but increases nitrogen resorption efficiency in a Mediterranean ecosystem
spellingShingle Drought reduces tree growing season lenght but increases nitrogen resorption efficiency in a Mediterranean ecosystem
Lobo Do Vale, Raquel
drought
tree growing
nitrogen
Mediterranean ecosystem
title_short Drought reduces tree growing season lenght but increases nitrogen resorption efficiency in a Mediterranean ecosystem
title_full Drought reduces tree growing season lenght but increases nitrogen resorption efficiency in a Mediterranean ecosystem
title_fullStr Drought reduces tree growing season lenght but increases nitrogen resorption efficiency in a Mediterranean ecosystem
title_full_unstemmed Drought reduces tree growing season lenght but increases nitrogen resorption efficiency in a Mediterranean ecosystem
title_sort Drought reduces tree growing season lenght but increases nitrogen resorption efficiency in a Mediterranean ecosystem
author Lobo Do Vale, Raquel
author_facet Lobo Do Vale, Raquel
Besson, Cathy Kurz
Caldeira, Maria
Chaves, Maria Manuela
Pereira, João Santos
author_role author
author2 Besson, Cathy Kurz
Caldeira, Maria
Chaves, Maria Manuela
Pereira, João Santos
author2_role author
author
author
author
dc.contributor.none.fl_str_mv Repositório da Universidade de Lisboa
dc.contributor.author.fl_str_mv Lobo Do Vale, Raquel
Besson, Cathy Kurz
Caldeira, Maria
Chaves, Maria Manuela
Pereira, João Santos
dc.subject.por.fl_str_mv drought
tree growing
nitrogen
Mediterranean ecosystem
topic drought
tree growing
nitrogen
Mediterranean ecosystem
description Mediterranean ecosystems are hotspots for climate change, as the highest impacts are forecasted for the Mediterranean region, mainly by more frequent and intense severe droughts. Plant phenology is a good indicator of species’ responses to climate change. In this study, we compared the spring phenology of cork oak trees (Quercus suber), an evergreen species, over 2 contrasting years, a mild year (2004) and a dry year (2005), which was the most severe drought since records exist. We evaluated the timing of occurrence, duration, and intensity of bud development, budburst, shoot elongation, trunk growth, and leaf senescence (phenophases) and assessed the nitrogen resorption efficiency from senescent to green leaves. The temperature was the main driver of budburst. Nevertheless, water had the main role of constraining all the other phenophases by strongly reducing the growing season length (48 %) and consequently the tree growth. Basal area increment was the most affected growth variable (36 %), although it occurred at a similar rate in the 2 years. Shoot elongation was also reduced (21 %), yet elongation occurred at a higher rate in the dry year compared to the mild year. Leaf senescence during the bulk period was higher in the dry year, in which leaves were shed at the same rate over a longer period. Nitrogen concentrations in green and senescent leaves were affected by drought and nitrogen resorption efficiency increased remarkably (C22 %). Our results highlight the importance of studying different phenological metrics to improve our understanding of the ecosystem’s responses to climate change. The faster dynamics observed in shoot elongation, while all other phenophases developed at the same rate, indicate that leaf area development is privileged in cork oak. Water availability was the main driver of spring growth in this Mediterranean ecosystem; however, growth may be affected by complex interplays between precipitation and temperature, such as higher temperatures during dry winters or heatwaves during spring, that are likely to result in water stress. Longer studies are needed to disentangle those interplays. Finally, a higher nitrogen resorption efficiency in response to drought appears to be an adaptive trait that mitigates the limitation in nitrogen uptake by the roots during drought and contributes to improving tree fitness in the short term but will probably exert a negative feedback on the nitrogen cycle in the long term, which might affect the ecosystem functioning under the forecasted droughts
publishDate 2019
dc.date.none.fl_str_mv 2019-04-11T10:14:07Z
2019
2019-01-01T00:00:00Z
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
dc.type.driver.fl_str_mv info:eu-repo/semantics/article
format article
status_str publishedVersion
dc.identifier.uri.fl_str_mv http://hdl.handle.net/10400.5/17726
url http://hdl.handle.net/10400.5/17726
dc.language.iso.fl_str_mv por
language por
dc.relation.none.fl_str_mv Biogeosciences, 16, 1265–1279, 2019
https://doi.org/10.5194/bg-16-1265-2019
dc.rights.driver.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
application/pdf
dc.publisher.none.fl_str_mv European Geosciences Union
publisher.none.fl_str_mv European Geosciences Union
dc.source.none.fl_str_mv reponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação
instacron:RCAAP
instname_str Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação
instacron_str RCAAP
institution RCAAP
reponame_str Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
collection Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
repository.name.fl_str_mv Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação
repository.mail.fl_str_mv mluisa.alvim@gmail.com
_version_ 1817549442858876928