Résumé
The seasonal and interannual variability of the terrestrial carbon cycle is regulated by the interactions of climate and ecosystem function. However, the key factors and processes determining the interannual variability of net ecosystem productivity (NEP) in different biomes are far from clear. Here, we quantified yearly anomalies of seasonal and annual NEP, net carbon uptake period (CUP), and the maximum daily NEP (NEPmax) in response to climatic variables in 24 deciduous broadleaf forest (DBF), evergreen forest (EF), and grassland (GRA) ecosystems that include at least eight years of eddy covariance observations. Over the 228 site-years studied, interannual variations in NEP were mostly explained by anomalies of CUP and NEPmax. CUP was determined by spring and autumn net carbon uptake phenology, which were sensitive to annual meteorological variability. Warmer spring temperatures led to an earlier start of net carbon uptake activity and higher spring and annual NEP values in DBF and EF, while warmer autumn temperatures in DBF, higher autumn radiation in EF, and more summer and autumn precipitation in GRA resulted in a later ending date of net carbon uptake and associated higher autumn and annual NEP. Anomalies in NEPmax s were determined by summer precipitation in DBF and GRA, and explained more than 50% of variation in summer NEP anomalies for all the three biomes. Results demonstrate the role of meteorological variability in controlling CUP and NEPmax, which in turn help describe the seasonal and interannual variability of NEP.
Auteurs, date et publication :
Auteurs Zheng Fu , Paul C. Stoy , Yiqi Luo , Jiquan Chen , Jian Sun , Leonardo Montagnani , Georg Wohlfahrt , Abdullah F. Rahman , Serge Rambal , Christian Bernhofer , Jinsong Wang , Gabriela Shirkey , Shuli Niu
Publication : Agricultural and Forest Meteorology
Date : 2025
Volume : 243
Pages : 9-18
Catégorie(s)
#CNRS #FORET PuechabonAuteurs, date et publication :
Auteurs Elvire Bestion , Staffan Jacob , Lucie Zinger , Lucie Di Gesu , Murielle Richard , Joël White , Julien Cote
Publication : Nature Ecology & Evolution
Date : 2017
Volume : 1
Issue : 6
Pages : 0161
Catégorie(s)
#CNRS #Metatron terrestreRésumé
While soil ecosystems undergo important modifications due to global change, the effect of soil properties on plant distributions is still poorly understood. Plant growth is not only controlled by soil physico-chemistry but also by microbial activities through the decomposition of organic matter and the recycling of nutrients essential for plants. A growing body of evidence also suggests that plant functional traits modulate species’ response to environmental gradients. However, no study has yet contrasted the importance of soil physico-chemistry, microbial activities and climate on plant species distributions, while accounting for how plant functional traits can influence species-specific responses. Using hierarchical effects in a multi-species distribution model, we investigate how four functional traits related to resource acquisition (plant height, leaf carbon to nitrogen ratio, leaf dry matter content and specific leaf area) modulate the response of 44 plant species to climatic variables, soil physico-chemical properties and microbial decomposition activity (i.e. exoenzymatic activities) in the French Alps. Our hierarchical trait-based model allowed to predict well 41 species according to the TSS statistic. In addition to climate, the combination of soil C/N, as a measure of organic matter quality, and exoenzymatic activity, as a measure of microbial decomposition activity, strongly improved predictions of plant distributions. Plant traits played an important role. In particular, species with conservative traits performed better under limiting nutrient conditions but were outcompeted by exploitative plants in more favorable environments. We demonstrate tight associations between microbial decomposition activity, plant functional traits associated to different resource acquisition strategies and plant distributions. This highlights the importance of plant–soil linkages for mountain plant distributions. These results are crucial for biodiversity modelling in a world where both climatic and soil systems are undergoing profound and rapid transformations.
Auteurs, date et publication :
Auteurs Camille Martinez‐Almoyna , Gabin Piton , Sylvain Abdulhak , Louise Boulangeat , Philippe Choler , Thierry Delahaye , Cédric Dentant , Arnaud Foulquier , Jérôme Poulenard , Virgile Noble , Julien Renaud , Maxime Rome , Amélie Saillard , Wilfried Thuiller , Tamara Münkemüller
Publication : Ecography
Date : 2025
Volume : 43
Issue : 10
Pages : 1550-1559
Catégorie(s)
#CNRS #Lautaret #UGARésumé
Studies on the dependence of the rates of ecosystem gas exchange on environmental parameters often rely on the up-scaling of leaf-level response curves (‘bottom-up’ approach), and/or the down-scaling of ecosystem fluxes (‘top-down’ approach), where one takes advantage of the natural diurnal covariation between the parameter of interest and photosynthesis rates. Partly independent from environmental variation, molecular circadian clocks drive ∼24 h oscillations in leaf-level photosynthesis, stomatal conductance and other physiological processes in plants under controlled laboratory conditions. If present and of sufficient magnitude at ecosystem scales, circadian regulation could lead to different results when using the bottom-up approach (where circadian regulation exerts a negligible influence over fluxes because the environment is modified rapidly) relative to the top-down approach (where circadian regulation could affect fluxes as it requires the passage of a few hours). Here we dissected the drivers of diurnal net CO2 exchange in canopies of an annual herb (bean) and of a perennial shrub (cotton) through a set of experimental manipulations to test for the importance of circadian regulation of net canopy CO2 exchange, relative to that of temperature and vapor pressure deficit, and to understand whether circadian regulation could affect the derivation of environmental flux dependencies. Contrary to conventional wisdom, we observed how circadian regulation exerted controls over net CO2 exchange that were of similar magnitude to the controls exerted by direct physiological responses to temperature and vapor pressure deficit. Diurnal patterns of net CO2 exchange could only be explained by considering effects of environmental responses combined with circadian effects. Consequently, we observed significantly different results when inferring the dependence of photosynthesis over temperature and vapor pressure deficit when using the top-down and the bottom up approaches.
Auteurs, date et publication :
Auteurs Víctor Resco de Dios , Arthur Gessler , Juan Pedro Ferrio , Josu G. Alday , Michael Bahn , Jorge del Castillo , Sébastien Devidal , Sonia García-Muñoz , Zachary Kayler , Damien Landais , Paula Martín-Gómez , Alexandru Milcu , Clément Piel , Karin Pirhofer-Walzl , Olivier Ravel , Serajis Salekin , David T. Tissue , Mark G. Tjoelker , Jordi Voltas , Jacques Roy
Publication : Agricultural and Forest Meteorology
Date : 2025
Volume : 239
Pages : 185-191
Catégorie(s)
#CNRS #Ecotron de MontpellierAuteurs, date et publication :
Auteurs Bruno Verdier , Isabelle Jouanneau , Benoit Simonnet , Christian Rabin , Tom J. M. Van Dooren , Nicolas Delpierre , Jean Clobert , Luc Abbadie , Régis Ferrière , Jean-François Le Galliard
Publication : Environmental Science & Technology
Date : 2014
Volume : 48
Issue : 15
Pages : 8744-8753
Catégorie(s)
#ANR-Citation #CNRS #Ecotron IleDeFrance #ENSRésumé
Biogenic volatile organic compounds (BVOC) emitted by plants can originate from both anabolism (metabolite production through anabolic processes) and catabolism (metabolite degradation by oxidative reactions). Drought can favor leaf oxidation by increasing the oxidative pressure in plant cells. Thus, under the precipitation decline predicted for the Mediterranean region, it can be expected both strong oxidation of anabolic BVOC within leaves and, as a result, enhanced catabolic BVOC emissions. Using an experimental rain exclusion device in a natural forest, we compared the seasonal course of the emissions of the main anabolic BVOC released by Q. pubescens (isoprene and methanol) and their catabolic products (MACR+MVK+ISOPOOH and formaldehyde, respectively) after 3 years of precipitation restriction (-30% of rain). Thus, we assume that this repetitive amplified drought promoted a chronic drought. BVOC emissions were monitored, on-line, with a PTR-ToF-MS. Amplified drought decreased all BVOC emissions rates in spring and summer by around 40-50 %, especially through stomatal closure, with no effect in autumn. Moreover, ratios between catabolic and anabolic BVOC remained unchanged with amplified drought, suggesting a relative stable oxidative pressure in Q. pubescens under the water stress applied. Moreover, these results suggest a quite good resilience of this species under the most severe climate change scenario in the Mediterranean region.
Auteurs, date et publication :
Auteurs Amélie Saunier , Elena Ormeño , Henri Wortham , Brice Temime-Roussel , Caroline Lecareux , Christophe Boissard , Catherine Fernandez
Publication : Frontiers in Plant Science
Date : 2025
Volume : 8
Pages : 71
Catégorie(s)
#CNRS #FORET O3HPRésumé
The circadian clock is a molecular timer of metabolism that affects the diurnal pattern of stomatal conductance (gs), amongst other processes, in a broad array of plant species. The function of circadian gs regulation remains unknown and here, we test whether circadian regulation helps to optimize diurnal variations in stomatal conductance. We subjected bean (Phaseolus vulgaris) and cotton (Gossypium hirsutum) canopies to fixed, continuous environmental conditions of photosynthetically active radiation, temperature, and vapour pressure deficit (free-running conditions) over 48 h. We modelled gs variations in free-running conditions to test for two possible optimizations of stomatal behaviour under circadian regulation: (i) that stomata operate to maintain constant marginal water use efficiency; or (ii) that stomata maximize C net gain minus the costs or risks of hydraulic damage. We observed that both optimization models predicted gs poorly under free-running conditions, indicating that circadian regulation does not directly lead to stomatal optimization. We also demonstrate that failure to account for circadian variation in gs could potentially lead to biased parameter estimates during calibrations of stomatal models. More broadly, our results add to the emerging field of plant circadian ecology, where circadian controls may partially explain leaf-level patterns observed in the field.
Auteurs, date et publication :
Auteurs Víctor Resco de Dios , William R. L. Anderegg , Ximeng Li , David T. Tissue , Michael Bahn , Damien Landais , Alexandru Milcu , Yinan Yao , Rachael H. Nolan , Jacques Roy , Arthur Gessler
Publication : Plants
Date : 2020
Volume : 9
Issue : 9
Pages : 1091
Catégorie(s)
#ANR-Citation #CNRS #Ecotron de MontpellierAuteurs, date et publication :
Auteurs Víctor Resco de Dios , Arthur Gessler , Juan Pedro Ferrio , Josu G. Alday , Michael Bahn , Jorge del Castillo , Sébastien Devidal , Sonia García-Muñoz , Zachary Kayler , Damien Landais , Paula Martín-Gómez , Alexandru Milcu , Clément Piel , Karin Pirhofer-Walzl , Olivier Ravel , Serajis Salekin , David T. Tissue , Mark G. Tjoelker , Jordi Voltas , Jacques Roy
Publication : GigaScience
Date : 2025
Volume : 5
Issue : 1
Pages : 43
Catégorie(s)
#ANR-Citation #CNRS #Ecotron de MontpellierRésumé
How plant-plant interactions will interact with global change drivers such as increased drought during the regeneration phase is a key question to forecast future vegetation dynamics. Chemical interaction and especially allelopathy and drought have been suggested to affect plant performance synergistically, i.e. that plant under drought stress would be more sensitive to allelochemicals and that exposure to allelopathic interactions could increase drought sensitivity through an inhibition of root development and mycorrhization. In this paper, we tested these hypotheses by using a controlled experiment with Quercus pubescens Mill. as a target species and three cooccurring species plus itself as source species. Allelopathic treatments consisted of annual provision of litter and monthly watering with green leaf aqueous extracts during 2 vegetation seasons starting from oak acorns. During the second vegetation season, a drought stress treatment was added on half of the seedlings. Allelopathy of cooccurring species reduced seedlings dimensions while Q. pubescens treatment increased it. During the second vegetation season, seedling growth rate and physiology were reduced by drought but poorly affected by allelopathic treatment. At the end of the experiment, drought stress and allelopathy from Cotinus coggygria and Pinus halepensis both reduced seedling biomass but had opposite effects on the root/shoot ratio. Drought and allelopathy did not interact significantly and, contrary to our hypothesis, there was a tendency of lower allelopathic effects under drought. Our results suggest that drought and allelopathy could additively alter seedling development, but the opposite effects of allelopathy and drought on the root/shoot ratio call for further experiments testing the interaction between these two factors.
Auteurs, date et publication :
Auteurs H. Hashoum , J. Gavinet , T. Gauquelin , V. Baldy , S. Dupouyet , C. Fernandez , A. Bousquet-Mélou
Publication : European Journal of Forest Research
Date : 2025
Volume : 140
Issue : 2
Pages : 333-343
Catégorie(s)
#CNRS #FORET O3HPAuteurs, date et publication :
Auteurs María‐José Endara , Phyllis D Coley , Natasha L Wiggins , Dale L Forrister , Gordon C Younkin , James A Nicholls , R Toby Pennington , Kyle G Dexter , Catherine A Kidner , Graham N Stone
Publication : New Phytologist
Date : 2025
Volume : 218
Issue : 2
Pages : 847-858