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Seedlings of two Acacia species from contrasting habitats show different photoprotective and antioxidative responses to drought and heatwaves / Agnieszka Wujeska-Klause in Annals of Forest Science, vol 72 n° 4 (June 2015)
[article]
Titre : Seedlings of two Acacia species from contrasting habitats show different photoprotective and antioxidative responses to drought and heatwaves Type de document : Article/Communication Auteurs : Agnieszka Wujeska-Klause, Auteur ; Gerd Bossinger, Auteur ; Michael Tausz, Auteur Année de publication : 2015 Article en page(s) : pp 403 - 414 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Végétation
[Termes IGN] Acacia aneura
[Termes IGN] Acacia melanoxylon
[Termes IGN] analyse comparative
[Termes IGN] chaleur
[Termes IGN] photosynthèse
[Termes IGN] sécheresse
[Termes IGN] zone aride
[Termes IGN] zone humideRésumé : (auteur) Key message : Two Acacia species adapted to contrasting habitats showed different response of photoprotective and antioxidative defence systems to imposed drought and heatwave.
Context : Predicted increases in drought frequency and intense heatwaves are expected to lead to dieback of sensitive tree species. Stomatal closure restricts CO2 input into the leaf, resulting in imbalances between light energy-driven electron transport rate and electron consumption in the Calvin cycle. Reactive oxygen species formed under these circumstances have to be kept under control by photoprotective and antioxidative defence systems.
Aims : We hypothesised that these defence systems behave differently in tree species from contrasting habitats.
Methods : Acacia aneura (adapted to arid habitats) and Acacia melanoxylon (adapted to humid habitats) were exposed to two water treatments for 50 days including two short heatwave periods. Responses were assessed by gas exchange, chlorophyll fluorescence and concentrations of antioxidants (phyllodes, roots).
Results : Photosynthesis and quantum yield of photochemistry decreased significantly in both Acacia species, especially after water was withheld in combination with the second heatwave episode. In phyllodes, the concentration of antioxidants remained unchanged until exposure to severe drought and heatwave conditions (except for A. melanoxylon where changes in glutathione concentration were observed prior to exposure to severe stress), but after water was withheld and the second heatwave occurred, oxidised forms of glutathione increased. After exposure to the second heatwave, well-watered seedlings of A. melanoxylon but not A. aneura increased ascorbic acid concentration in phyllodes. Under well-watered conditions, Acacia species also showed increased concentration of antioxidants in roots following heatwaves.
Conclusions : Both Acacia species showed photodamage to photosystem II (PSII) after water was withheld and the second heatwave imposed, but with more gradual response in A. aneura. Total concentration of investigated antioxidants increased in response to the first (A. melanoxylon) and second (A. aneura) heatwaves rather than drought stress alone.Numéro de notice : A2015-425 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1007/s13595-014-0438-5 Date de publication en ligne : 19/11/2014 En ligne : https://doi.org/10.1007/s13595-014-0438-5 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=77012
in Annals of Forest Science > vol 72 n° 4 (June 2015) . - pp 403 - 414[article]An improved species distribution model for Scots pine and downy oak under future climate change in the NW Italian Alps / Giorgio Vacchiano in Annals of Forest Science, vol 72 n° 3 (May 2015)
[article]
Titre : An improved species distribution model for Scots pine and downy oak under future climate change in the NW Italian Alps Type de document : Article/Communication Auteurs : Giorgio Vacchiano, Auteur ; Renzo Motta, Auteur Année de publication : 2015 Article en page(s) : pp 321 - 334 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Végétation
[Termes IGN] Aoste (val d')
[Termes IGN] distribution spatiale
[Termes IGN] inventaire forestier étranger (données)
[Termes IGN] Normalized Difference Vegetation Index
[Termes IGN] Pinus sylvestris
[Termes IGN] Quercus pubescens
[Termes IGN] sécheresseRésumé : (auteur) Context : Scots pine is currently declining in most inner alpine sectors of southern Europe. The relative contribution of climate, land use change, and disturbances on the decline is poorly understood. What will be the future distribution of the species? Is vegetation shifting toward oak-dominated forests? What is the role of extreme drought years?
Aims : The aims of the study were to determine drivers of current distribution of Scots pine and downy oak in Aosta valley (SW Alps), to extrapolate species distribution models to year 2080 (Special Report on Emissions Scenarios (SRES) A1B), and to assess the correlation between pine vitality after the extreme droughts of 2003 and 2006, and modeled longterm vegetation changes.
Methods : Ensemble distribution models were created using climate, topography, soil, competition, natural disturbances, and land use. Species presence was derived from a regional forest inventory. Pine response to drought of 2003–2006 was assessed by Normalized Difference Vegetation Index (NDVI) differencing and correlated to modeled cover change between 2080 and present.
Results : Scots pine and downy oak were more likely to occur under higher climatic aridity. Scots pine was also associated to higher wildfire frequency, land use intensity, and lack of competition. In a warming scenario, pine experienced an elevational displacement. This was partially counteracted if no land abandonment was hypothesized. Downy oak cover increased in all scenarios. Short- and long-term drought responses of pine were unrelated.
Conclusion : Warming will induce an upward displacement of pine, but this can be partially mitigated by maintaining a more intense land use. The drought-induced decline in pine vitality after extreme years did not overlap to the modeled species response under climate warming; responses to short-term drought must be more thoroughly understood in order to predict community shifts.Numéro de notice : A2015-454 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1007/s13595-014-0439-4 Date de publication en ligne : 19/12/2014 En ligne : https://doi.org/10.1007/s13595-014-0439-4 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=77111
in Annals of Forest Science > vol 72 n° 3 (May 2015) . - pp 321 - 334[article]Les forêts tempérées face aux conséquences du changement climatique : est-il primordial de favoriser une plus forte diversité d’arbres dans les peuplements forestiers ? / Charlotte Grossiord in Revue forestière française, Vol 67 n° 2 (mars 2015)
[article]
Titre : Les forêts tempérées face aux conséquences du changement climatique : est-il primordial de favoriser une plus forte diversité d’arbres dans les peuplements forestiers ? Type de document : Article/Communication Auteurs : Charlotte Grossiord, Auteur ; Arthur Gessler, Auteur ; André Granier, Auteur ; Damien Bonal, Auteur Année de publication : 2015 Article en page(s) : pp 99 - 110 Note générale : Bibliographie Langues : Français (fre) Descripteur : [Termes IGN] biodiversité
[Termes IGN] changement climatique
[Termes IGN] forêt tempérée
[Termes IGN] peuplement forestier
[Termes IGN] sécheresse
[Vedettes matières IGN] Végétation et changement climatiqueRésumé : (Auteur) Une plus forte biodiversité dans les peuplements forestiers est suggérée comme étant un mode de gestion permettant d’adapter les forêts à l’accentuation des sécheresses dans le futur. Nous présentons ici une synthèse sur la relation entre diversité en essences d’arbre et résistance à la sécheresse des peuplements forestiers tempérés. Des tendances contrastées pour cette relation ont été observées en fonction des types forestiers étudiés, des essences présentes dans le peuplement, ou du contexte pédoclimatique local. La généralisation de modes de gestion forestière intégrant des mélanges de plusieurs essences ne semble donc pas nécessairement assurer une meilleure résistance à la sécheresse des peuplements forestiers tempérés. Numéro de notice : A2015-736 Affiliation des auteurs : non IGN Thématique : BIODIVERSITE/FORET Nature : Article DOI : 10.4267/2042/57901 En ligne : https://doi.org/10.4267/2042/57901 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=78437
in Revue forestière française > Vol 67 n° 2 (mars 2015) . - pp 99 - 110[article]MODIS-based vegetation index has sufficient sensitivity to indicate stand-level intra-seasonal climatic stress in oak and beech forests / Tomáš Hlásny in Annals of Forest Science, vol 72 n° 1 (January 2015)
[article]
Titre : MODIS-based vegetation index has sufficient sensitivity to indicate stand-level intra-seasonal climatic stress in oak and beech forests Type de document : Article/Communication Auteurs : Tomáš Hlásny, Auteur ; Ivan Barka, Auteur ; Zuzana Sitková, Auteur ; et al., Auteur Année de publication : 2015 Article en page(s) : pp 109 - 125 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] analyse diachronique
[Termes IGN] chaleur
[Termes IGN] classification par réseau neuronal
[Termes IGN] données météorologiques
[Termes IGN] Fagus (genre)
[Termes IGN] forêt tempérée
[Termes IGN] image Aqua-MODIS
[Termes IGN] image Terra-MODIS
[Termes IGN] indice de stress
[Termes IGN] Normalized Difference Vegetation Index
[Termes IGN] prévision météorologique
[Termes IGN] Quercus (genre)
[Termes IGN] sécheresseRésumé : (auteur) Context : Variation in photosynthetic activity of trees induced by climatic stress can be effectively evaluated using remote sensing data. Although adverse effects of climate on temperate forests have been subjected to increased scrutiny, the suitability of remote sensing imagery for identification of drought stress in such forests has not been explored fully.
Aim : The study seeks to evaluate the sensitivity of MODIS-based vegetation index to heat and drought stress in temperate forests, and to explore the differences in stress response of oaks and beech.
Methods : We identified 8 oak and 13 beech pure and mature stands, each covering between 4 and 13 MODIS pixels. For each pixel, we extracted a time series of MODIS NDVI from 2000 to 2010. We identified all sequences of continuous unseasonal NDVI decline to be used as the response variable indicative of environmental stress. Neural network-based regression modelling was then applied to identify the climatic variables that best explain observed NDVI declines.
Results : Tested variables explained 84–97 % of the variation in NDVI, whilst air temperature-related climate extremes were found to be the most influential. Beech showed a linear response to the most influential climatic predictors, while oak responded in a unimodal pattern suggesting a better coping mechanism.
Conclusions : MODIS NDVI has proved sufficiently sensitive as a stand-level indicator of climatic stress acting upon temperate broadleaf forests, leading to its potential use in predicting drought stress from meteorological observations and improving parameterisation of forest stress indices.Numéro de notice : A2015-382 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article DOI : 10.1007/s13595-014-0404-2 Date de publication en ligne : 30/07/2014 En ligne : https://doi.org/10.1007/s13595-014-0404-2 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76874
in Annals of Forest Science > vol 72 n° 1 (January 2015) . - pp 109 - 125[article]Disturbances in European beech water relation during an extreme drought / Marianne Peiffer in Annals of Forest Science, vol 71 n° 7 (October 2014)
[article]
Titre : Disturbances in European beech water relation during an extreme drought Type de document : Article/Communication Auteurs : Marianne Peiffer, Auteur ; Nathalie Bréda, Auteur ; Vincent Badeau, Auteur ; et al., Auteur Année de publication : 2014 Article en page(s) : pp 821 - 829 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] comportement
[Termes IGN] evaporation
[Termes IGN] Fagus (genre)
[Termes IGN] forêt
[Termes IGN] humidité du sol
[Termes IGN] indice foliaire
[Termes IGN] Lorraine
[Termes IGN] sécheresseRésumé : (Auteur) Context
In the context of a probable increase in intensity and frequency of extreme summer drought events, a better understanding of the key processes involved in water relations is needed to improve the theoretical foundations of predictive process-based models.
Aims
This paper aims to analyse how temperate deciduous trees cope with water shortage.
Methods
The exceptional summer drought of 2003 in Europe provided an opportunity to monitor stomatal conductance and twig water potential in European beech (Fagus sylvatica L.) at predawn and midday and to analyse variations with respect to leaf height within the canopy. By comparing our field measurements of twig water potential to values found in the literature, we confirmed the strong impact of soil water shortage on crown water relations.
Results
This paper shows that (1) the vertical gradient of stomatal conductance within the crown disappeared under extreme soil water depletion; (2) at maximum drought intensity, predawn twig water potential (ψ pd) reached −2.3 MPa at a height of 14 m in the crown and −2.0 MPa at a height of 10 m. The significant differences in ψ pd between the two measurement heights in the canopy may be due to night transpiration; (3) there was a close relationship between predawn twig water potential and relative extractable soil water; (4) as drought conditions intensified, there was a close relationship between canopy radiation interception and predawn water potential, as estimated daily from relative extractable soil water.Numéro de notice : A2014-536 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1007/s13595-014-0383-3 Date de publication en ligne : 23/05/2014 En ligne : https://doi.org/10.1007/s13595-014-0383-3 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=74149
in Annals of Forest Science > vol 71 n° 7 (October 2014) . - pp 821 - 829[article]Réservation
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