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1. Growing in Scarcity: Pre-Hispanic Rain-Fed Agriculture in the Semi-Arid and Frost-Prone Andean Altiplano (Bolivia)

Author

Pablo Cruz, Richard Joffre, Thibault Saintenoy, and Jean-Joinville Vacher

Subjects
Andes, landscape mapping, pre-hispanic agriculture, rain-fed cultivation, traditional ecological knowledge, Agriculture
Abstract

Ancient Andean agricultural landscapes have been the subject of a large number of archaeological and agro-ecological studies, which generally refer to regions with favourable environmental conditions or, in the case of arid and semi-arid environments, those with irrigation facilities. The aim of this article is to present and analyse the pre-Hispanic rain-fed farming systems widely represented in two adjacent regions of Bolivia’s arid and cold southern Altiplano. The search for archaeological agricultural areas combined aerial analysis and field surveys. Agro-ecological characterisation was based on historical and ethnographic studies of the region’s present-day populations. Despite their geographical proximity, similar environmental conditions, and same agropastoral way of life, the typology of cultivated areas developed in the southern altiplano differs significantly. Within this same framework of adaptation and resilience, the sectorisation of agricultural systems observed in these two regions reveals a regional productive specialisation that favoured internal exchanges and exchanges with other regions. These differences are related to two models of non-centralised, low-inequality societies—one strongly based on cohesion and the other characterised by greater fragmentation and social conflict—underlining the limits of strict environmental determinism in shaping agricultural landscapes. These results provide new food for thought in the debate on the use and value of rain-fed agricultural practices and more broadly on the diversity of adaptations by human societies in extreme and unstable environmental contexts.

Published
2024
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2. Pukara de los wak’a. Cerros, muros concéntricos y divinidades tutelares en el altiplano centro-sur andino

Author

Pablo Cruz and Richard Joffre

Subjects
wak’a, tutelary hill, ceremonial pukara, highlands, History of Civilization, CB3-482
Abstract

According to information provided by colonial documentary sources, a large number of ceremonial spaces linked to the ancient cults of the tutelary wak’a were identified in different regions of the central-southern Andean highlands (Bolivia). Placed on the tops of low hills and close to the settlements, they are distinguished by a variable number of stone walls arranged in a concentric manner. Although their chronology begins in pre-Hispanic times, the majority of these sites continued to be in use in the long term. Articulating new archaeological data with historical and ethnographic information, this paper presents and analyzes different aspects of these ceremonial spaces in the Andean highlands.

Published
2020
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3. Environmental control of land-atmosphere CO2 fluxes from temperate ecosystems: a statistical approach based on homogenized time series from five land-use types

Author

Virginie Moreaux, Bernard Longdoz, Daniel Berveiller, Nicolas Delpierre, Eric Dufrêne, Jean-Marc Bonnefond, Christophe Chipeaux, Richard Joffre, Jean-Marc Limousin, Jean-Marc Ourcival, Katja Klumpp, Olivier Darsonville, Aurore Brut, Tiphaine Tallec, Eric Ceschia, Gérémy Panthou, and Denis Loustau

Subjects
net co2 ecosystem exchange, ecosystem respiration, gross primary production, spectral analysis, random forest analysis, Meteorology. Climatology, QC851-999
Abstract

We assembled homogenized long-term time series, up to 19 years, of measurements of net ecosystem exchange of CO2 (NEE) and its partitioning between gross primary production (GPP) and respiration (Reco) for five different ecosystems representing the main plant functional types (PFTs) in France. Part of these data was analyzed to determine the influence of the main environmental variables on carbon fluxes between temperate ecosystems and the atmosphere, and to investigate the temporal patterns of their variations. A multi-temporal statistical analysis of the time series was conducted using random forest (RF) and wavelet coherence approaches. The RF analysis showed that, in all ecosystems, the incident solar radiation was highly correlated with GPP and that GPP was better correlated with the temporal variations of NEE than Reco. The air temperature was the second most important driver in ecosystems with seasonal foliage, i.e., deciduous forest, cropland and grassland; whereas variables related to air or soil drought were prominent in evergreen forest sites. The environmental control on CO2 fluxes was tighter at high frequency suggesting an increased resilience to environmental variations at longer time spans. The spectral analysis performed on three of the five sites selected revealed contrasting temporal patterns of the cross-coherence between CO2 fluxes and climate variables among ecosystems; these were related to the respective PFT, management and soil conditions. In all PFTs, the power spectrum of GPP was well correlated with NEE and clearly different from Reco. The spectral correlation analysis showed that the canopy phenology and disturbance regime condition the spectral correlation patterns of GPP and Reco with the soil moisture and atmospheric vapour deficit.

Published
2020
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4. Amplified Drought Alters Leaf Litter Metabolome, Slows Down Litter Decomposition, and Modifies Home Field (Dis)Advantage in Three Mediterranean Forests

Author

Elodie Quer, Susana Pereira, Thomas Michel, Mathieu Santonja, Thierry Gauquelin, Guillaume Simioni, Jean-Marc Ourcival, Richard Joffre, Jean-Marc Limousin, Adriane Aupic-Samain, Caroline Lecareux, Sylvie Dupouyet, Jean-Philippe Orts, Anne Bousquet-Mélou, Raphaël Gros, Marketa Sagova-Mareckova, Jan Kopecky, Catherine Fernandez, and Virginie Baldy

Subjects
experimental drought, Home Field Advantage (HFA), litter quality, Mediterranean forest, metabolomics, Botany, QK1-989
Abstract

In Mediterranean ecosystems, the projected rainfall reduction of up to 30% may alter plant–soil interactions, particularly litter decomposition and Home Field Advantage (HFA). We set up a litter transplant experiment in the three main forests encountered in the northern part of the Medi-terranean Basin (dominated by either Quercus ilex, Quercus pubescens, or Pinus halepensis) equipped with a rain exclusion device, allowing an increase in drought either throughout the year or concentrated in spring and summer. Senescent leaves and needles were collected under two precipitation treatments (natural and amplified drought plots) at their “home” forest and were left to decompose in the forest of origin and in other forests under both drought conditions. MS-based metabolomic analysis of litter extracts combined with multivariate data analysis enabled us to detect modifications in the composition of litter specialized metabolites, following amplified drought treatment. Amplified drought altered litter quality and metabolomes, directly slowed down litter decomposition, and induced a loss of home field (dis)advantage. No indirect effect mediated by a change in litter quality on decomposition was observed. These results may suggest major alterations of plant–soil interactions in Mediterranean forests under amplified drought conditions.

Published
2022
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5. Social adaptive responses to a harsh and unpredictable environment: insights from a pre-Hispanic andean society

Author

Pablo Cruz, Richard Joffre, Cyril Bernard, Nancy Egan, Bruno Roux, and Thierry Winkel

Subjects
andean highlands, archaeology, food storage, gini indices, settlement infrastructure, social inequality, sustainability, Biology (General), QH301-705.5, Ecology, QH540-549.5
Abstract

The scarcity or unpredictability of natural resources is a threat to cooperation within human societies. Exacerbated competition between individuals could affect social cohesion and collective action, generate conflicts over natural resources, and compromise their sustainable use. Yet, our in-depth archaeological study of the arid Andean highlands of Bolivia reveals the sustainable development of a complex agrarian society in a harsh environment marked, moreover, by a prolonged climatic degradation from the 13th to the 15th centuries. The 49 community settlements studied comprised independent family households that managed their own economic resources. A detailed study of the granary and housing structures of 549 of these households provided a strong quantitative data set for an analysis of Gini coefficients for grain storage capacity and housing area. This agro-pastoral society flourished with neither notable inequalities of wealth between villagers nor apparent long-lasting conflicts between villages. By sharing local knowledge, labor, and natural resources, this society succeeded both in limiting power and wealth concentration, and in sustainably producing food surpluses to be exchanged with neighboring populations. These results indicate a high degree of social cohesion and low levels of social and wealth inequality, similar to other well-established horticultural and agricultural societies around the world. We propose a conceptual model of low inequality in agrarian societies subject to extreme or unstable environments, where the sharing of knowledge, resources, and labor are the adaptive social responses to cope with the uncertainty in natural resources. The sustainability of the society is then guaranteed by a balance between collective action and family-based social organization.

Published
2022
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6. When the Past Lives in the Present. Agrarian Landscapes and Historical Social Dynamics in the Southern Andes (Quebrada de Humahuaca, Jujuy, Argentina)

Author

Pablo Cruz, Nancy Egan, Richard Joffre, Jorge L. Cladera, and Thierry Winkel

Subjects
agrarian landscape, Andes, landscape mapping, pre-Hispanic agriculture, Spanish colonial period, peasant dynamics, Agriculture
Abstract

This article examines the agrarian landscape in one part of the southern Andes (Quebrada of Humahuaca, Jujuy, Argentina). The region possesses extensive and well-preserved archaeological remains of agricultural systems, which stretch back to pre-Hispanic times. In this study, we employ an interdisciplinary approach in our analysis of the components that structure the agrarian landscape, especially those historical processes that intervened in its formation. The creation of a cartographic base, built from remote sensing and fieldwork data, allowed for the identification of four principal components of the landscape, each of which correspond to distinct phases or periods that mark the region’s history. Our study shows that, in contrast to what is observed in many other rural areas, the successive productive dynamics that developed in the area did not result in the destruction of previous productive structures. Rather, the agrarian landscape in the study area presents a multi-temporal agglutinating combination or composition, which transcends historical discontinuities in the productive matrix. This is owing to the partial reutilisation of previous structures in each period; however, religious and cultural factors play an important role. The agrarian landscape we studied is not only a passive result of human activity, but also a force influencing the productive and lifestyle decisions of the peasant populations that live there today. Our research amplifies the understanding of agrarian landscapes in the Andes and shows how past temporalities are articulated with the present through a dialectical process.

Published
2021
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7. Discontinuities in quinoa biodiversity in the dry Andes: An 18-century perspective based on allelic genotyping.

Author

Thierry Winkel, María Gabriela Aguirre, Carla Marcela Arizio, Carlos Alberto Aschero, María Del Pilar Babot, Laure Benoit, Concetta Burgarella, Sabrina Costa-Tártara, Marie-Pierre Dubois, Laurène Gay, Salomón Hocsman, Margaux Jullien, Sara María Luisa López-Campeny, María Marcela Manifesto, Miguel Navascués, Nurit Oliszewski, Elizabeth Pintar, Saliha Zenboudji, Héctor Daniel Bertero, and Richard Joffre

Subjects
Medicine, Science
Abstract

History and environment shape crop biodiversity, particularly in areas with vulnerable human communities and ecosystems. Tracing crop biodiversity over time helps understand how rural societies cope with anthropogenic or climatic changes. Exceptionally well preserved ancient DNA of quinoa (Chenopodium quinoa Willd.) from the cold and arid Andes of Argentina has allowed us to track changes and continuities in quinoa diversity over 18 centuries, by coupling genotyping of 157 ancient and modern seeds by 24 SSR markers with cluster and coalescence analyses. Cluster analyses revealed clear population patterns separating modern and ancient quinoas. Coalescence-based analyses revealed that genetic drift within a single population cannot explain genetic differentiation among ancient and modern quinoas. The hypothesis of a genetic bottleneck related to the Spanish Conquest also does not seem to apply at a local scale. Instead, the most likely scenario is the replacement of preexisting quinoa gene pools with new ones of lower genetic diversity. This process occurred at least twice in the last 18 centuries: first, between the 6th and 12th centuries-a time of agricultural intensification well before the Inka and Spanish conquests-and then between the 13th century and today-a period marked by farming marginalization in the late 19th century likely due to a severe multidecadal drought. While these processes of local gene pool replacement do not imply losses of genetic diversity at the metapopulation scale, they support the view that gene pool replacement linked to social and environmental changes can result from opposite agricultural trajectories.

Published
2018
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8. A pre-Hispanic religious landscape on the arid Andean altiplano of Bolivia

Author

Pablo Cruz, Richard Joffre, and Jean J. Vacher

Subjects
Archeology, General Arts and Humanities
Abstract

Research carried out in the Carangas region of highland Bolivia has identified a surprising concentration of pre-Hispanic religious sites, which are linked both to ancient Andean cults of wak'a (sacred mountains, tutelary hills and mummified ancestors) and to the Incan settlement of the region. Of these sites, one ceremonial centre stands out for its unprecedented characteristics for the Andes.

Published
2023

9. Pre-hispanic agricultural dynamics in the Quebrada of Morohuasi (Salta, Argentina)

Author

Pablo Cruz, Richard Joffre, Thierry Winkel, Bruno Roux, Christian Vitry, UE CISOR CONICET, Universidad Nacional de Jujuy, Jujuy, Argentina, Centre d’Ecologie Fonctionnelle et Evolutive (CEFE), Université Paul-Valéry - Montpellier 3 (UPVM)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut Agro Montpellier, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Université de Montpellier (UM), Universidad Nacional de Salta, Subsecretaría de Patrimonio de la Provincia de Salta, Argentina, and This research was funded by MSH-SUD (Maison des Sciences de l’Homme SUD, France: Project PANARCHI 2017–2018, IRD/CNRS/UCM/UNJU), and ECOS-SUD (Scientific Cooperation Program Argentina/France: Project ARCHIPA 2020–2022).

Subjects
Archeology, southern Andes, Formative Period, [SHS.ARCHEO]Humanities and Social Sciences/Archaeology and Prehistory, [SDV.SA.AEP]Life Sciences [q-bio]/Agricultural sciences/Agriculture, economy and politics, [SHS.ANTHRO-SE]Humanities and Social Sciences/Social Anthropology and ethnology, History of agriculture, [SDE.ES]Environmental Sciences/Environmental and Society, [SHS]Humanities and Social Sciences, Inka, Land use changes, mitmaqkuna, pre-Hispanic agriculture, Agricultural landscapes
Abstract

Preprint de l'article publié le 06/12/2022 dans la revue "Ñawpa Pacha - Journal of the Institute of Andean Studies (Berkeley)", URL: https://doi.org/10.1080/00776297.2022.2136305; International audience; The Quebrada de Morohuasi (Salta Province, Argentina), located in a semi-arid high-altitude environment, is known to host vast pre-Hispanic cultivation areas. Recent archaeological studies carried out in the agricultural area of Morohuasi allow for a better definition and understanding of the social and productive dynamics that took place there. Field records and AMS dating indicate two main productive phases that were discontinuous in time. These show an initial phase during the Formative Period, between the 1st and 4th centuries CE, during which the agricultural substratum was formed, and a final phase during the first decades of the 15th century CE that was related to the establishment of an agricultural colony under the control of the Inkas. Although the same cultivation plots were utilized during both phases, the mode and relations of production were substantially different, particularly in the second phase with the participation of contingents of mitmaqkunas brought from other regions.; Ubicada en un ambiente semiárido de altura, la Quebrada de Morohuasi (Salta, Argentina) es conocida por albergar vastas áreas de cultivo prehispánicas. Los recientes estudios arqueológicos realizados en el área agrícola de Morohuasi permiten una mejor definición y comprensión de las dinámicas sociales y productivas que allí se dieron. Los registros de campo y las dataciones AMS realizadas indican dos fases productivas principales discontinuas en el tiempo. Una fase inicial durante el Período Formativo, entre los siglos I y IV CE, en la cual se conforma el sustrato agrícola, y una fase final durante las primeras décadas del siglo XV CE, relacionada con el establecimiento de una colonia agrícola bajo control de los inkas. Si durante ambas fases se cultivaron las mismas parcelas, el modo y las relaciones de producción fueron sustancialmente distintas, destacándose particularmente en la segunda la participación de contingentes de mitmaqkunas llevados desde otras regiones.

Published
2022

11. Covariations between plant functional traits emerge from constraining parameterization of a terrestrial biosphere model

Author

Georg Wohlfahrt, Marc Peaucelle, Damiano Gianelle, Nicolas Delpierre, Dan Yakir, Philippe Ciais, Timo Vesala, Sylvain Kuppel, Eric Dufrêne, Mark A. Sutton, Thomas Kolb, Nicolas Vuichard, Cédric Bacour, Andreas Ibrom, Ladislav Šigut, Lutz Merbold, Sebastian Wolf, Leonardo Montagnani, Anders Lindroth, Nina Buchmann, Jiquan Chen, Carsten Gruening, Josep Peñuelas, Luca Belelli Marchesini, Tomomichi Kato, Stefano Minerbi, Andrej Varlagin, Beverly E. Law, Ivan Mammarella, Cristina Gimeno-Colera, Ankur R. Desai, Richard Joffre, Nicolas Viovy, Lukas Hörtnagl, Carole Helfter, Peter D. Blanken, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), NOVELTIS [Sté], ICOS-ATC (ICOS-ATC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Modélisation des Surfaces et Interfaces Continentales (MOSAIC), Global Ecology Unit CREAF-CEAB-CSIC, Universitat Autònoma de Barcelona (UAB), Vrije Universiteit Amsterdam [Amsterdam] (VU), Institute of Agricultural Sciences [Zürich], Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Department of Environmental Sciences [Toledo USA], University of Toledo, Ecologie Systématique et Evolution (ESE), Université Paris-Sud - Paris 11 (UP11)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS), Department of Atmospheric and Oceanic Sciences [Madison], University of Wisconsin-Madison, Centro di Ecologia Alpina, Fondazione Edmund Mach - Edmund Mach Foundation [Italie] (FEM), Joint Research Centre, Edinburgh Research Station, Centre for Ecology and Hydrology, Swiss Federal Institute of Technology, Danmarks Tekniske Universitet = Technical University of Denmark (DTU), Centre d’Ecologie Fonctionnelle et Evolutive (CEFE), Université Paul-Valéry - Montpellier 3 (UPVM)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Hokkaido University [Sapporo, Japan], Department of Physical Geography and Ecosystem Science [Lund], Lund University [Lund], Department of Physics [Helsinki], Falculty of Science [Helsinki], Helsingin yliopisto = Helsingfors universitet = University of Helsinki-Helsingin yliopisto = Helsingfors universitet = University of Helsinki, Institute of Agricultural Sciences, Ecole Polytechnique Fédérale de Zurich, Provincia Autonoma di Bolzano Servizi Forestali, Servizi Forestali, Provincia Autonoma di Bolzano, Agenzia per l'Ambiente, Department of Physics [Montréal], McGill University = Université McGill [Montréal, Canada], A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences [Moscow] (RAS), Department of Physics, Institute of Ecology, Leopold Franzens Universität Innsbruck - University of Innsbruck, Kiel University, Weizmann Institute of Science [Rehovot, Israël], Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Vrije universiteit = Free university of Amsterdam [Amsterdam] (VU), Technical University of Denmark [Lyngby] (DTU), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Université Paul-Valéry - Montpellier 3 (UPVM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut de Recherche pour le Développement (IRD [France-Sud]), University of Helsinki-University of Helsinki, University of Innsbruck, Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), Universitat Autònoma de Barcelona [Barcelona] (UAB), VU University Amsterdam, Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich), Université Paul-Valéry - Montpellier 3 (UM3)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-École pratique des hautes études (EPHE)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Hokkaido University, McGill University, A.N.Severtsov Institute of Ecology and Evolution, and Weizmann Institute of Science

Subjects
0106 biological sciences, Biosphere model, Optimization, Eddy covariance, Atmospheric sciences, 010603 evolutionary biology, 01 natural sciences, Ecology and Environment, Terrestrial model, Data assimilation, FluxNet, Ecosystem model, Settore BIO/07 - ECOLOGIA, ORCHIDEE, Plant functional traits, Ecosystem, Plant acclimatation, Ecology, Evolution, Behavior and Systematics, ComputingMilieux_MISCELLANEOUS, SDG 15 - Life on Land, [SDV.EE]Life Sciences [q-bio]/Ecology, environment, Global and Planetary Change, Ecology, 010604 marine biology & hydrobiology, Biosphere, 15. Life on land, Assimilation, Trait, Environmental science, Plant acclimation
Abstract

Aim: The mechanisms of plant trait adaptation and acclimation are still poorly understood and, consequently, lack a consistent representation in terrestrial biosphere models (TBMs). Despite the increasing availability of geo-referenced trait observations, current databases are still insufficient to cover all vegetation types and environmental conditions. In parallel, the growing number of continuous eddy-covariance observations of energy and CO2 fluxes has enabled modellers to optimize TBMs with these data. Past attempts to optimize TBM parameters mostly focused on model performance, overlooking the ecological properties of ecosystems. The aim of this study was to assess the ecological consistency of optimized trait-related parameters while improving the model performances for gross primary productivity (GPP) at sites.Location: Worldwide. Time period: 1992–2012. Major taxa studied: Trees and C3 grasses. Methods: We optimized parameters of the ORCHIDEE model against 371 site-years of GPP estimates from the FLUXNET network, and we looked at global covariation among parameters and with climate. Results: The optimized parameter values were shown to be consistent with leaf-scale traits, in particular, with well-known trade-offs observed at the leaf level, echoing the leaf economic spectrum theory. Results showed a marked sensitivity of trait-related parameters to local bioclimatic variables and reproduced the observed relationships between traits and climate. Main conclusions: Our approach validates some biological processes implemented in the model and enables us to study ecological properties of vegetation at the canopy level, in addition to some traits that are difficult to observe experimentally. This study stresses the need for: (a) implementing explicit trade-offs and acclimation processes in TBMs; (b) improving the representation of processes to avoid model-specific parameterization; and (c) performing systematic measurements of traits at FLUXNET sites in order to gather information on plant ecophysiology and plant diversity, together with micro-meteorological conditions.

Published
2019

12. What fluxes are telling us so far ? A naïve reanalysis of CO2 fluxes over the past 18 years

Author

Virginie Moreaux, Paul Berbigier, Daniel Berveiller, Jean-Marc Bonnefond, Christophe Chipeaux, Nicolas Delpierre, Olivier Darsonville, Eric Dufrene, André Granier, Richard Joffre, Katja Klumpp, sebastien lafont, Jean-Michel Limousin, Bernhard Longdoz, Denis Loustau, Kamel Piquemal, Jean-Yves Pontarlier, Serge Rambal, Jean-François Soussana, Interactions Sol Plante Atmosphère (UMR ISPA), Institut National de la Recherche Agronomique (INRA)-Ecole Nationale Supérieure des Sciences Agronomiques de Bordeaux-Aquitaine (Bordeaux Sciences Agro), Université Paris-Sud - Paris 11 (UP11), Ecologie des Forêts Méditerranéennes (URFM), Institut National de la Recherche Agronomique (INRA), Unité Mixte de Recherche sur l'Ecosystème Prairial - UMR (UREP), Institut National de la Recherche Agronomique (INRA)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS), SILVA (SILVA), Institut National de la Recherche Agronomique (INRA)-Université de Lorraine (UL)-AgroParisTech, Centre d’Ecologie Fonctionnelle et Evolutive (CEFE), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Université Paul-Valéry - Montpellier 3 (UPVM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut de Recherche pour le Développement (IRD [France-Sud]), Université de Liège, Ecole nationale supérieure des ingénieurs en arts chimiques et technologiques, Collège de Direction (CODIR), Université Paris-Saclay, Institut National de la Recherche Agronomique (INRA)-AgroParisTech-Université de Lorraine (UL), Université Paul-Valéry - Montpellier 3 (UPVM)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Ecole nationale supérieure des ingénieurs en arts chimiques et technologiques (ENSIACET), Institut National Polytechnique (Toulouse) (Toulouse INP), and Université de Toulouse (UT)-Université de Toulouse (UT)

Subjects
[SDV]Life Sciences [q-bio], [SDE]Environmental Sciences, ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
2018

13. Rooting plasticity in wild and cultivated Andean Chenopodium species under soil water deficit

Author

Richard Joffre, Ricardo Álvarez-Flores, Thierry Winkel, Anh Nguyen-Thi-Truc, Santiago Peredo-Parada, Centre d’Ecologie Fonctionnelle et Evolutive (CEFE), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Université Paul-Valéry - Montpellier 3 (UPVM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut de Recherche pour le Développement (IRD [France-Sud]), Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE)-Université de Montpellier (UM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Université Paul-Valéry - Montpellier 3 (UM3), Université Paul-Valéry - Montpellier 3 (UM3)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-École pratique des hautes études (EPHE)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Université Paul-Valéry - Montpellier 3 (UPVM)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-École Pratique des Hautes Études (EPHE), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)

Subjects
0106 biological sciences, root growth, [SDV.SA.AGRO]Life Sciences [q-bio]/Agricultural sciences/Agronomy, Taproot, Plant Science, 01 natural sciences, phenotypic plasticity, Chenopodium quinoa, C. hircinum, ComputingMilieux_MISCELLANEOUS, water deficit, plant domestication, 2. Zero hunger, Chenopodium pallidicaule, Biomass (ecology), Chenopodium quinoa Willd, root topology, biology, Ecotype, Chenopodium, Plant physiology, 04 agricultural and veterinary sciences, seed mass, Root architecture, Natural and human selection, C. pallidicaule, root shoot ratio, root plasticity, human and natural selection, Chenopodium hircinum, Soil Science, ecotype, root length, rhizotron, complex mixtures, plant adaptation, [SDV.BV]Life Sciences [q-bio]/Vegetal Biology, Agroecology, root system architecture, 15. Life on land, biology.organism_classification, root traits, Agronomy, Rhizotron, rooting depth, 040103 agronomy & agriculture, 0401 agriculture, forestry, and fisheries, biomass allocation, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, 010606 plant biology & botany
Abstract

International audience; Background and Aims: Rooting plasticity is critical for plants exploiting patchy soil-water resources, but empirical evidence remains controversial due to complex root/soil interactions in natural and agricultural environments. We compared cultivated and wild Chenopodium populations from distinct agroecological background to assess their rooting plasticity when exposed to contrasting wet-dry soil profiles in a controlled environment.Methods: Four treatments of increasing dryness were applied during 6 weeks in plants of Chenopodium hircinum, Chenopodium pallidicaule and two ecotypes (wet- and dry-habitat) of Chenopodium quinoa grown in rhizotrons. Root system architecture and growth were sequentially mapped. At the end of the experiment, plant and root morphological traits and dry biomass were measured.Results: Contrary to the other two species, C. quinoa showed accelerated taproot growth in dry soil conditions. The dry-habitat C. quinoa ecotype showed consistently higher plant traits related to longer, coarser, and more numerous root segments which give it a faster taproot growth and sustained root branching at depth in dry soil.Conclusions: High rooting plasticity confers the advantage of fast root elongation and deep soil exploration under soil water deficit. Variation in intrinsic root traits and plastic responses among Chenopodium populations controls their root foraging capacity facing patchy soil-water resources.

Published
2018

14. Mediterranean land surfaces under global change : towards a roadmap for sustainable land use in Europe

Author

Didier Genin, Mohamed Alifriqui, Robin Duponnois, Richard Joffre, Thierry Gauquelin, Wadi Badri, Bruno Fady, Mohamed Aderghal, Magda Bou Dagher-Kharrat, Geneviève Michon, Hervé Sanguin, Arezki Derridj, Romain Simenel, Virginie Baldy, Laurent Auclair, Said Slimani, Ezékiel Baudoin, Yves Prin, Catherine Fernandez, Antoine Galiana, Institut méditerranéen de biodiversité et d'écologie marine et continentale (IMBE), Avignon Université (AU)-Aix Marseille Université (AMU)-Institut de recherche pour le développement [IRD] : UMR237-Centre National de la Recherche Scientifique (CNRS), Laboratoire Mixte International MEDITER ‘‘Terroirs Méditerranéens’’, Institut de Recherche pour le Développement (IRD [France-Ouest]), Gouvernance, Risque, Environnement, Développement (GRED), Université Paul-Valéry - Montpellier 3 (UM3)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut de Recherche pour le Développement (IRD), Centre d’Ecologie Fonctionnelle et Evolutive (CEFE), Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE)-Université de Montpellier (UM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Université Paul-Valéry - Montpellier 3 (UM3), Laboratoire des symbioses tropicales et méditerranéennes (UMR LSTM), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Université Montpellier 1 (UM1)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Laboratoire Population-Environnement-Développement (LPED), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU), Ecologie des Forêts Méditerranéennes [Avignon] (URFM 629), Institut National de la Recherche Agronomique (INRA), Département Sciences de la Vie et de la Terre, Saint Joseph University, Faculté des Sciences Biologiques et des Sciences Agronomiques, Université Mouloud Mammeri [Tizi Ouzou] (UMMTO), Faculté des Sciences Ben M’sik, Département de Biologie, Laboratoire Ecologie et Environnement, Université Hassan II [Casablanca] (UH2MC), Faculté des Sciences Semlalia, Département de Biologie, Laboratoire Ecologie et Environnement Unité associée au CNRST - URAC 32, Université Cadi Ayyad [Marrakech] (UCA), E3R – Equipe de Recherche sur la Région et la Régionalisation – CERGéo, Laboratoire Mixte International MEDITER ‘‘Terroirs Méditerranéens’’ UM5A, Université Mohammed V de Rabat [Agdal], Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Université de Montpellier (UM), Centre National de la Recherche Scientifique (CNRS)-Institut de recherche pour le développement [IRD] : UMR237-Aix Marseille Université (AMU)-Avignon Université (AU), Université Paul-Valéry - Montpellier 3 (UPVM)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Université Paul-Valéry - Montpellier 3 (UPVM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut de Recherche pour le Développement (IRD [France-Sud]), Ecologie des Forêts Méditerranéennes (URFM), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Voltz M. (ed.), Ludwig W. (ed.), Leduc Christian (ed.), Bouarfa S. (ed.), Université Paul-Valéry - Montpellier 3 (UPVM)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), and Université Mohammed V de Rabat [Agdal] (UM5)

Subjects
0106 biological sciences, Mediterranean climate, 010504 meteorology & atmospheric sciences, Socio-ecological systems, Biodiversity, Arecaceae, 01 natural sciences, Mediterranean Basin, forest, Quercus, K01 - Foresterie - Considérations générales, Abies pinsapo, Photosynthèse, biodiversity, Global and Planetary Change, changement climatique, Ecology, forêt méditerranéenne, sustainability, Communauté rurale, Deciduous, Sustainability, Pistacia, Écosystème forestier, P01 - Conservation de la nature et ressources foncières, Biodiversité, Abies, forêt tempérée, Argania spinosa, P40 - Météorologie et climatologie, mediterranean basin, gestion des ressources naturelles, 010603 evolutionary biology, bassin méditerranéen, socio-ecological systems, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Quercus suber, Corylus, E50 - Sociologie rurale, Forest, Functioning, Propriété physicochimique du sol, global change, 0105 earth and related environmental sciences, Land use, Composition botanique, Climat, Mediterranean basin, Global change, 15. Life on land, Evergreen, Zone méditerranéenne, Pinus, biodiversité forestière, Tetraclinis articulata, 13. Climate action, Juniperus, Threatened species, Peganum, fonctionnement socio écologique, Pinus halepensis, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, écosystème forestier méditerranéen
Abstract

Mediterranean forests are found in the Mediterranean basin, California, the South African Cape Province, South and southwestern Australia and parts of Central Chile. They represent 1.8 % of the world forest areas of which the vast majority is found in the Mediterranean basin, where historical and paleogeographic episodes, long-term human influence and geographical and climatic contrasts have created ecosystemic diversity and heterogeneity. Even if evergreen is dominant, deciduous trees are also represented, with different forest types including dense stands with a closed canopy (forests sensu stricto) and pre-forestal or pre-steppic structures with lower trees density and height. The Mediterranean basin is also a hot spot of forest species and genetic diversity, with 290 woody species versus only 135 for non-Mediterranean Europe. However, the characteristics of the Mediterranean area (long-standing anthropogenic pressure, significant current human activity and broad biodiversity) make it one of the world’s regions most threatened by current changes. Four examples of Mediterranean forest types, present in south and north of the Mediterranean basin and more or less threatened, are developed in order to show that linking “hard sciences” and humanities and social sciences is necessary to understand these complex ecosystems. We show also that these forests, in spite of specific climatic constraints, can also be healthy and productive and play a major ecological and social role. Furthermore, even if the current human activity and global change constitute a risk for these exceptional ecosystems, Mediterranean forests represent a great asset and opportunities for the future of the Mediterranean basin.

Published
2018

15. Interpreting canopy development and physiology using a European phenology camera network at flux sites

Author

Bernard Longdoz, Cristina Gimeno, Christophe Moisy, Christine Moureaux, Andres Plaza-Aguilar, A. Ibrom, Matthew Wilkinson, Tanguy Manise, Pasi Kolari, Katja Klumpp, Eero Nikinmaa, Thomas Grünwald, Charles George, Dario Papale, Richard Joffre, Barbara Köstner, Lukas Hörtnagl, Lisa Wingate, Georg Wohlfahrt, Birgit Gielen, Werner Eugster, Albert Porcar-Castell, Hella Ellen Ahrends, Jean-Marc Ourcival, Marta Galvagno, Werner L. Kutsch, Bernard Heinesch, Michael Sprintsin, Tatsuro Nakaji, Olaf Kolle, Margareta Hellström, Bernard Genty, Anders Lindroth, Dominique Guyon, James I. L. Morison, Gianluca Filippa, John Grace, Edoardo Cremonese, Jérôme Ogée, Jin-Hong Guan, Albin Hammerle, Janne Levula, Toshie Mizunuma, Alexander Knohl, Dan Yakir, Manuela Balzarolo, Mirco Migliavacca, Interactions Sol Plante Atmosphère (UMR ISPA), Institut National de la Recherche Agronomique (INRA)-Ecole Nationale Supérieure des Sciences Agronomiques de Bordeaux-Aquitaine (Bordeaux Sciences Agro), Aosta Valley Regional Environmental Protection Agency (ARPA), University of Edinburgh, Max-Planck-Institut für Biogeochemie (MPI-BGC), Alice Holt Lodge, Forest Research [Great Britain], Gembloux Agro-Bio Tech [Gembloux], Université de Liège, European Academy of Bozen-Bolzano (EURAC), Universität Innsbruck [Innsbruck], Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Centro de Estudios Ambientales del Mediterraneo, University of Helsinki, Hokkaido University [Sapporo, Japan], Georg-August-University [Göttingen], Johann Heinrich von Thünen Institute, Federal Research Institute for Rural Areas, Forestry and Fisheries, Institute of Sea Fisheries, Risø National Laboratory for Sustainable Energy (Risø DTU), Technical University of Denmark [Lyngby] (DTU), Universiteit Antwerpen [Antwerpen], Università degli studi della Tuscia [Viterbo], Département Ecologie des Forêts, Prairies et milieux Aquatiques (DEPT EFPA), Institut National de la Recherche Agronomique (INRA), Technische Universität Dresden = Dresden University of Technology (TU Dresden), Centre d’Ecologie Fonctionnelle et Evolutive (CEFE), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Université Paul-Valéry - Montpellier 3 (UPVM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut de Recherche pour le Développement (IRD [France-Sud]), Lund University [Lund], Centre for Ecology and Hydrology (CEH), Natural Environment Research Council (NERC), Ecologie et Ecophysiologie Forestières [devient SILVA en 2018] (EEF), Institut National de la Recherche Agronomique (INRA)-Université de Lorraine (UL), Biologie végétale et microbiologie environnementale - UMR7265 (BVME), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Weizmann Institute of Science [Rehovot, Israël], Universität zu Köln, Department of Plant Sciences (Cambridge, UK), University of Cambridge [UK] (CAM), Interactions Sol Plante Atmosphère (ISPA), Forest Research, Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich), Hokkaido University, Georg-August-Universität Göttingen, Technische Universität Dresden (TUD), Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE)-Université de Montpellier (UM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Université Paul-Valéry - Montpellier 3 (UM3), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Weizmann Institute of Science, Helsingin yliopisto = Helsingfors universitet = University of Helsinki, Georg-August-University = Georg-August-Universität Göttingen, Danmarks Tekniske Universitet = Technical University of Denmark (DTU), Universiteit Antwerpen = University of Antwerpen [Antwerpen], Université Paul-Valéry - Montpellier 3 (UPVM)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Universität zu Köln = University of Cologne, Department of Forest Sciences, Department of Physics, Eero Nikinmaa / Principal Investigator, Viikki Plant Science Centre (ViPS), Ecosystem processes (INAR Forest Sciences), Micrometeorology and biogeochemical cycles, and Forest Ecology and Management

Subjects
0106 biological sciences, Canopy, DECIDUOUS BROADLEAF FOREST, NET CARBON UPTAKE, 010504 meteorology & atmospheric sciences, [SDV]Life Sciences [q-bio], lcsh:Life, 01 natural sciences, regression analysis, digital image, SDG 13 - Climate Action, spatiotemporal analysis, SDG 15 - Life on Land, 4112 Forestry, concentration (composition), Ecology, Phenology, Physics, lcsh:QE1-996.5, Temperate forest, deciduous forest, Vegetation, parameterization, Europe, Chemistry, Deciduous, TEMPERATE FOREST, 1181 Ecology, evolutionary biology, canopy development, Growing season, photoperiod, phenology, 114 Physical sciences, 010603 evolutionary biology, Ecology and Environment, ECOSYSTEM RESPIRATION, pigment, lcsh:QH540-549.5, Segmented regression, SCOTS PINE, Biology, 1172 Environmental sciences, Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences, Earth-Surface Processes, videography, LEAF CHLOROPHYLL, carbon dioxide, temperature, 15. Life on land, Evergreen, carbon sequestration, lcsh:Geology, lcsh:QH501-531, GREENHOUSE-GAS BALANCE, 13. Climate action, DIGITAL REPEAT PHOTOGRAPHY, CHLOROPHYLL CONTENT, Environmental science, nutrient availability, lcsh:Ecology, SOIL-TEMPERATURE, Physical geography, soil moisture
Abstract

Plant phenological development is orchestrated through subtle changes in photoperiod, temperature, soil moisture and nutrient availability. Presently, the exact timing of plant development stages and their response to climate and management practices are crudely represented in land surface models. As visual observations of phenology are laborious, there is a need to supplement long-term observations with automated techniques such as those provided by digital repeat photography at high temporal and spatial resolution. We present the first synthesis from a growing observational network of digital cameras installed on towers across Europe above deciduous and evergreen forests, grasslands and croplands, where vegetation and atmosphere CO2 fluxes are measured continuously. Using colour indices from digital images and using piecewise regression analysis of time series, we explored whether key changes in canopy phenology could be detected automatically across different land use types in the network. The piecewise regression approach could capture the start and end of the growing season, in addition to identifying striking changes in colour signals caused by flowering and management practices such as mowing. Exploring the dates of green-up and senescence of deciduous forests extracted by the piecewise regression approach against dates estimated from visual observations, we found that these phenological events could be detected adequately (RMSE < 8 and 11 days for leaf out and leaf fall, respectively). We also investigated whether the seasonal patterns of red, green and blue colour fractions derived from digital images could be modelled mechanistically using the PROSAIL model parameterised with information of seasonal changes in canopy leaf area and leaf chlorophyll and carotenoid concentrations. From a model sensitivity analysis we found that variations in colour fractions, and in particular the late spring `green hump' observed repeatedly in deciduous broadleaf canopies across the network, are essentially dominated by changes in the respective pigment concentrations. Using the model we were able to explain why this spring maximum in green signal is often observed out of phase with the maximum period of canopy photosynthesis in ecosystems across Europe. Coupling such quasi-continuous digital records of canopy colours with co-located CO2 flux measurements will improve our understanding of how changes in growing season length are likely to shape the capacity of European ecosystems to sequester CO2 in the future.

Published
2015

16. Using near-infrared reflectance spectroscopy to predict carbon, nitrogen and phosphorus content in heterogeneous plant material

Author

Richard Joffre, Claudie Houssard, and Dominique Gillon

Subjects
Nutrient, chemistry, Phosphorus, Principal component analysis, Calibration, chemistry.chemical_element, Mineralogy, Biology, Nitrogen, Carbon, Ecology, Evolution, Behavior and Systematics, Wet chemistry, Spectral line
Abstract

The aim of this study was to produce calibration equations between near-infrared reflectance (NIR) spectra and the concentrations of carbon, nitrogen, and phosphorus in heterogeneous material: from living needles to litter in Pinus halepensis stands subjected to prescribed burnings. The aim was to determine whether calibrations should be conducted within each stage in the transformation of needles (local calibrations), giving relationships that were accurate but valid only for each particular stage, or whether it was possible to integrate the various forms of variation in needles (global calibrations) while retaining an acceptable accuracy. A principal component analysis calculated from the sample spectral data was used to distinguish three different sets, each sharing spectral characteristics and corresponding to three categories of needle: needles collected on the pines (N), falling needles (F), and litter (L), and each containing samples collected from the burnt sites and a control site. Samples representative of all the forms of variation in spectral properties were selected from within each category and their carbon, nitrogen, and phosphorus concentrations were measured using standard wet chemistry methods; these constituted the calibration sets n, f, and l. Calibrations were produced between the nutrient concentrations and the NIR spectra of the calibration sets n, f, and l and the grouped sets (n+f, f+l, n+f+l). The results of local calibrations made from each individual category showed that the carbon, nitrogen, and phosphorus concentrations were accurately predictable by NIR spectra. The global calibrations made by lumping together several categories were valid for a wider range of concentrations and for spectrally heterogeneous materials and in most cases were just as accurate as the local calibrations produced from each individual category.

Published
2017

17. Near-Infrared Reflectance Spectroscopy allows rapid and simultaneous evaluation of chloroplast pigments and antioxidants, carbon isotope discrimination and nitrogen content in Populus spp. leaves

Author

Jordi Fernàndez-Martínez, Isabel Fleck, Richard Joffre, Beatriz Fernández-Marín, José Ignacio García-Plazaola, and Massimo Zacchini

Subjects
0106 biological sciences, Photoprotection, Nitrogen, Forestry, Management, Monitoring, Policy and Law, Biology, Photosynthesis, 010603 evolutionary biology, 01 natural sciences, chemistry.chemical_compound, Phytoremediation, Bioremediation, Nutrient, Populus, Nirs, Neoxanthin, chemistry, Bioenergy, Botany, Partial least squares regression, Carbon Isotope Discrimination, Antioxidant, 010606 plant biology & botany, Nature and Landscape Conservation
Abstract

Poplar species are economically important sources of timber and bioenergy and they also have a valuable application in phytoremediation and in forest restoration programmes. The characterization of their responses in the face of environmental constraints is essential to ascertain their adaptation capacity. Quantification of chloroplast pigments and antioxidant compounds, nutrients and carbon isotope discrimination (Δ13C) of a large set of samples in ecophysiological studies is important for determining the plant’s physiological responses. Δ13C and nitrogen are parameters of special interest for providing information on photosynthesis, water relations and nutritional characteristics in forest stands. Photoprotective and antioxidant compounds participate in the physiological defence of plants subjected to stressful environmental conditions. The measurement of these leaf components by traditional techniques is laborious and expensive. To evaluate them, a calibration model was obtained using Near-Infrared Reflectance Spectroscopy (NIRS) and chemical analyses of Populus spp. leaves sampled from different clones in different years under different physiological conditions. Predictive calibration equations for the concentration of chloroplast pigments (Chlorophylls a and b, lutein, neoxanthin, β-carotene (β-Car), VAZ (violaxanthin + antheraxanthin + zeaxanthin), epoxidation index (EI = (0.5·antheraxanthin + violaxanthin)/VAZ)), antioxidants (total phenolics (TPhe), ascorbate and α-tocopherol), Δ13C and N content were established using a partial least squares regression algorithm. Results showed a remarkable accuracy of the calibration equations for quantifying several antioxidative and photoprotective defence compounds such as neoxanthin (R2 = 0.844), β-Car (R2 = 0.827), VAZ (R2 = 0.846), EI (R2 = 0.831) and excellent accuracy for TPhe (R2 = 0.957), N (R2 = 0.963) and Δ13C (R2 = 0.922). As shown, results can be obtained on multiple physiological attributes with a single measurement, saving time and money and demonstrating the suitability of NIRS for ecophysiological purposes and bioremediation programs.

Published
2017

18. Relationships between photochemical reflectance index and light-use efficiency in deciduous and evergreen broadleaf forests

Author

Jean-Marc Ourcival, Daniel Berveiller, Serge Rambal, Nicolas Delpierre, Gabriel Hmimina, Richard Joffre, Eric Dufrêne, and Kamel Soudani

Subjects
Deciduous, Soil Science, Environmental science, Geology, Enhanced vegetation index, Computers in Earth Sciences, Evergreen, Photochemical Reflectance Index, Normalized Difference Vegetation Index, Remote sensing
Abstract

article i nfo In this study, we evaluate the relationships between the photochemical reflectance index (PRI) and light-use efficiency (LUE) based on eight years of continuous in situ measurements acquired on a half-hourly basis for PRI, NDVI (Normalized Difference Vegetation Index), the main micrometeorological variables and net CO2 ex- changedataintwodeciduousandevergreenmatureforests.Morespecifically,theobjectivesofthisstudyinclude

Published
2014

19. Which strategy is best to predict soil properties of a local site from a national Vis–NIR database?

Author

Fabien Goge, Richard Joffre, Claudy Jolivet, Cécile Gomez, Université de Montpellier (UM), Laboratoire d'étude des Interactions Sol - Agrosystème - Hydrosystème (UMR LISAH), Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), InfoSol (InfoSol), and Institut National de la Recherche Agronomique (INRA)

Subjects
010504 meteorology & atmospheric sciences, Property (programming), Calibration (statistics), [SDV]Life Sciences [q-bio], Soil Science, computer.software_genre, 01 natural sciences, CALCIUM, Spectral database, ANALYSE SPECTRALE, CALIBRAGE, Soil properties, PROPRIETE PHYSICOCHIMIQUE, 0105 earth and related environmental sciences, Mathematics, SOL, Soil library, Database, National library, SPECTROMETRIE INFRAROUGE, Vis-NIR spectroscopy, Local regression, 04 agricultural and veterinary sciences, BASE DE DONNEES, 15. Life on land, MODELISATION, FER, Regression, CARBONE ORGANIQUE, ARGILE, Spiking, CAPACITE D'ECHANGE CATIONIQUE, [SDE]Environmental Sciences, 040103 agronomy & agriculture, 0401 agriculture, forestry, and fisheries, National database, Data mining, Scale (map), computer, Near infrared spectroscopy, Fast Fourier transform local weighted regression
Abstract

International audience; Numerous studies on the prediction of soil properties from visible and near-infrared spectroscopy, based on large libraries at county scale or small size soil libraries at local scales have been reported in literature. However, difficulties appear when large libraries are used to estimate the soil properties of a small area. The aim of this paper was to compare various strategies to predict soil properties of local samples using a French national database. Models were built: i) from the national database alone and ii) from the national database spiked with subsets of the local database. Two regression methods were tested: partial least square [PLS] and a local regression method (fast Fourier transform local weighted [FFT-LW]). No general rule was obtained in this study as the best strategy differed according to the property under study. It seems that when strong spectral features are related to the characteristic under study (as for CaCO3 content), the addition of local samples did not bring a decisive advantage over calibration based on a wide national database. There are three important and encouraging points of this work to emphasize: i) the evidence of the added value brought by the national library for the prediction of some soil properties over a local area, ii) the pertinence of spiking with local samples to the global database to reach accurate predictions, and iii) the interest of the FFT-LW non-linear method. As we examined only one local site with peculiar land-use and geologic characteristics, further researches are needed to elucidate the way in which these results depend on intrinsic properties of the local site samples and on the relationship between spectral features and considered soil properties.

Published
2014

20. Ectomycorrhizal fungal diversity in Quercus ilex Mediterranean woodlands: variation among sites and over soil depth profiles in hyphal exploration types, species richness and community composition

Author

Serge Rambal, Richard Joffre, Franck Richard, Nicolas Martin-St Paul, Oula Shahin, Centre d’Ecologie Fonctionnelle et Evolutive (CEFE), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Université Paul-Valéry - Montpellier 3 (UPVM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut de Recherche pour le Développement (IRD [France-Sud]), and French Research Agency (ANR), through the Drought + (ANR-06-VULN-003-01) and Systruf (09-STRA-10-01) projects. Additional support was provided by the European project CARBOEXTREME (FP7-ENV-2008-1, project number 226701)

Subjects
0106 biological sciences, Mediterranean climate, biology, ectomycorrhizas, Ecology, [SDE.MCG]Environmental Sciences/Global Changes, exploration types, Rare species, Biodiversity, Woodland, 15. Life on land, biology.organism_classification, 010603 evolutionary biology, 01 natural sciences, diversity, Botany, Soil horizon, Russulaceae, Species richness, quercus ilex, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, General Agricultural and Biological Sciences, Relative species abundance, mediterranean forest, 010606 plant biology & botany
Abstract

International audience; Understanding the factors underlying the distribution of biodiversity is a challenging issue in ecology. Here, we examined the distribution patterns of ectomycorrhizal fungal diversity across the soil profile in three Quercus ilex forests. Contact exploration type strongly dominated at all sites, but was most prevalent in the upper, organic-rich soil layers. At each site, three quarters of the ectomycorrhizal tips and 59% of taxa were restricted to the ten first centimeters of the soil profile. The relative abundance of the dominant family Russulaceae increased with increasing soil depth. Species composition varied significantly among sites, with most species being rare. Species that occurred in only one of the three sites accounted for 78.9 % of all species, and 57.3 % of species were represented by a single ECM root tip. Our results suggest that (i) rare species at both local and regional scales contribute to the highly diverse fungal assemblages in Mediterranean forests and (ii) multi-sites studies including the whole soil profile are needed to provide comprehensive overviews of the taxonomic and functional diversities of ectomycorrhizal communities

Published
2013

21. Panarchy of an indigenous agroecosystem in the globalized market: The quinoa production in the Bolivian Altiplano

Author

Muriel Tichit, Jean-Joinville Vacher, Carmen Del Castillo, Marco Chevarria-Lazo, Anaïs Vassas-Toral, Jean-François Tourrand, François Léger, Manuela Vieira-Pak, Thierry Winkel, Juan-Peter Nina-Laura, Richard Joffre, Serge Rambal, Pierre Bommel, Geneviève Cortes, Pierre Gasselin, Centre d’Ecologie Fonctionnelle et Evolutive (CEFE), Université Paul-Valéry - Montpellier 3 (UM3)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-École pratique des hautes études (EPHE)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Gestion des ressources renouvelables et environnement (Cirad-Es-UPR 47 GREEN), Département Environnements et Sociétés (Cirad-ES), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad), Institut National de la Recherche Agronomique (INRA), Acteurs, Ressources et Territoires dans le Développement (UMR ART-Dev), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Paul-Valéry - Montpellier 3 (UM3)-Université de Perpignan Via Domitia (UPVD)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad), Universidad Mayor de San Andrés (UMSA), Innovation et Développement dans l'Agriculture et l'Alimentation (UMR Innovation), Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad), Sciences pour l'Action et le Développement : Activités, Produits, Territoires (SADAPT), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, Agrónomos y Veterinarios sin Fronteras (AVSF), Federal University of Lavras, Patrimoines locaux, Environnement et Globalisation (PALOC), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU), Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE)-Université de Montpellier (UM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Université Paul-Valéry - Montpellier 3 (UM3), Unité de recherche Paysannerie, Territoires, Environnement, Marchés et politiques Publiques (MONA), Facultad de Agronomia, Agronomes et Vétérinaires Sans Frontières, Departamento de Biologia, Universidade Federal de Lavras (UFLA), Patrimoines Locaux et Gouvernance (PALOC), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD), ANR-06-PADD-011-EQUECO, Université Paul-Valéry - Montpellier 3 (UPVM)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Gestion des ressources renouvelables et environnement (UPR GREEN), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Université Paul-Valéry - Montpellier 3 (UPVM)-Université de Perpignan Via Domitia (UPVD)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Universidade Federal de Lavras = Federal University of Lavras (UFLA), Université Paul-Valéry - Montpellier 3 (UPVM)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-École pratique des hautes études (EPHE), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN), Centre National de la Recherche Scientifique (CNRS)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Université de Montpellier (UM)-Université de Perpignan Via Domitia (UPVD)-Université Paul-Valéry - Montpellier 3 (UPVM), and AgroParisTech-Institut National de la Recherche Agronomique (INRA)

Subjects
010504 meteorology & atmospheric sciences, F08 - Systèmes et modes de culture, [SDV]Life Sciences [q-bio], Geography, Planning and Development, Agency (philosophy), 010501 environmental sciences, 01 natural sciences, 11. Sustainability, Economics, integrated assessment, Gouvernance, Economic geography, Structure agricole, Production alimentaire, media_common, 2. Zero hunger, [SDV.EE]Life Sciences [q-bio]/Ecology, environment, Global and Planetary Change, Utilisation des terres, adaptive cycle, Ecology, E90 - Structure agraire, 1. No poverty, Social dynamics, Agroécosystème, Psychological resilience, Mondialisation, land use change, Exploitation agricole familiale, media_common.quotation_subject, Management, Monitoring, Policy and Law, Petite exploitation agricole, rural livelihood strategy, Globalization, Vulnerability assessment, Development economics, E50 - Sociologie rurale, transformative change, 0105 earth and related environmental sciences, Adaptive capacity, Moyens d'existence, E80 - Économie familiale et artisanale, 15. Life on land, Développement régional, approches participatives, Quinoa, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Commons, Panarchy
Abstract

International audience; Agricultural globalization is blamed for destructive impacts on small farms in developing countries. Yet, many local societies are proactive in the face of these changes and show high adaptive capacity. Investigating their transformations with an integrative perspective and enough hindsight may reveal some of the bases of their resilience and adaptive capacity. Using field data and the panarchy concept of resilience theory, we analyzed the territorial and social dynamics of quinoa growers' communities in southern Bolivia over the last four decades, a case study of regime shift in a poverty-stricken rural society which deliberately entered the global food market. Linking the dynamics of the household economy to the territorial and social subsystems over several decades, we gained insights into the interactions that shaped the rise of quinoa production in the region. We found that a vivid tradition of mobility allowing for pluriactivity on-and off-farm, combined with community self-governance, explains how local populations succeeded in articulating individual agency with collective control over their commons of land, seed resources, and social rules. Our vulnerability analysis points to landscape homogenization, social inequity, and increased dependence on external factors as potential sources of unsustainability. We conclude that, to cope with the changes of unprecedented magnitude they are facing, local producers should retain social cohesion and autonomous governance, without giving up on their heritage of mobility and economic redundancy. As regards theory, we identified cross-scale subsystem configurations critical for regime shifts, and confirm the value of panarchy in capturing complex socioecological dynamics.

Published
2016

22. The Mediterranean region under climate change : a scientific update

Author

Thierry Gauquelin, Geneviève Michon, Richard Joffre, Robin Duponnois, Didier Genin, Bruno Fady, Magda Bou Agher-Kharrat, Arezki Derridj, Said Slimani, Wadi Badri, Mohamed Alifriqu, I., Laurent Auclair, Romain Simenel, Mohamed Aderghal, Ezékiel Baudoin, Antoine Galiana, Yves Prin, Hervé Sanguin, Catherine Fernandez, Virginie Baldy, Institut méditerranéen de biodiversité et d'écologie marine et continentale (IMBE), Centre National de la Recherche Scientifique (CNRS)-Institut de recherche pour le développement [IRD] : UMR237-Aix Marseille Université (AMU)-Avignon Université (AU), Institut de Recherche pour le Développement (IRD), Centre d’Ecologie Fonctionnelle et Evolutive (CEFE), Université Paul-Valéry - Montpellier 3 (UM3)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-École pratique des hautes études (EPHE)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Laboratoire des symbioses tropicales et méditerranéennes (UMR LSTM), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Université Montpellier 1 (UM1)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Laboratoire Population-Environnement-Développement (LPED), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU), Ecologie des Forêts Méditerranéennes [Avignon] (URFM 629), Institut National de la Recherche Agronomique (INRA), Faculté des Sciences Biologiques et des Sciences Agronomiques, Université Mouloud Mammeri [Tizi Ouzou] (UMMTO), University of Tizi-Ouzou, Faculté des Sciences Ben M’sik, Département de Biologie, Laboratoire Ecologie et Environnement, Université Hassan II [Casablanca] (UH2MC), Patrimoines Locaux et Gouvernance (PALOC), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD), E3R – Equipe de Recherche sur la Région et la Régionalisation – CERGéo, Laboratoire Mixte International MEDITER ‘‘Terroirs Méditerranéens’’ UM5A, Université Mohammed V de Rabat [Agdal], Laboratoire d'Ecologie Microbienne - UMR 5557 (LEM), Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Vétérinaire de Lyon (ENVL)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de la Recherche Agronomique (INRA)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS), Centre d'Ecologie des Systèmes Aquatiques Continentaux (CESAC), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Thiébault, S. and Moatti, Jean-Paul, Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Université Paul-Valéry - Montpellier 3 (UPVM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut de Recherche pour le Développement (IRD [France-Sud]), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Ecologie des Forêts Méditerranéennes (URFM), Institut National de la Recherche Agronomique (INRA)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Ecole Nationale Vétérinaire de Lyon (ENVL), Avignon Université (AU)-Aix Marseille Université (AMU)-Institut de recherche pour le développement [IRD] : UMR237-Centre National de la Recherche Scientifique (CNRS), Université Paul-Valéry - Montpellier 3 (UPVM)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Université Mohammed V de Rabat [Agdal] (UM5), Université de Lyon-Université de Lyon-Ecole Nationale Vétérinaire de Lyon (ENVL)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Université Paul-Valéry - Montpellier 3 (UPVM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Institut de Recherche pour le Développement (IRD [France-Sud]), Thiébault, S. (ed.), and Moatti, Jean-Paul (ed.)

Subjects
Litière forestière, FORET, STRUCTURE, GESTION, F40 - Écologie végétale, P40 - Météorologie et climatologie, FONCTIONNEMENT DE L'ECOSYSTEME, FACTEUR ANTHROPIQUE, [SHS]Humanities and Social Sciences, Matière organique du sol, Écologie forestière, K01 - Foresterie - Considérations générales, SYSTEME AGROSYLVOPASTORAL, ComputingMilieux_MISCELLANEOUS, Changement climatique, VARIABILITE, BIODIVERSITE, HISTOIRE, Zone méditerranéenne, EVOLUTION, SYSTEME AGRAIRE, FACTEUR CLIMATIQUE, CHANGEMENT CLIMATIQUE, PAYS MEDITERRANEENS ZONE MEDITERRANEENE, Forêt, Écosystème forestier, P01 - Conservation de la nature et ressources foncières, Biodiversité
Abstract

International audience

Published
2016

23. Sub-chapter 2.4.1. Mediterranean forests, biocultural heritage and climate change

Author

Robin Duponnois, Magda Bou Dagher, Mohamed Alifriqui, Wadi Badri, Thierry Gauquelin, Arezki Derridj, Romain Simenel, Ezékiel Baudoin, Richard Joffre, Virginie Baldy, Antoine Galiana, Hervé Sanguin, Geneviève Michon, Said Slimani, Didier Genin, Bruno Fady, Mohamed Aderghal, Yves Prin, Laurent Auclair, and Catherine Fernandez

Subjects
Mediterranean climate, Geography, Ecology, Climate change
Published
2016

24. The Sustainability of Quinoa Production in Southern Bolivia: from Misrepresentations to Questionable Solutions. Comments on Jacobsen (2011, J. Agron. Crop Sci. 197: 390-399)

Author

G. Rivière, Serge Rambal, J. Bourliaud, A. Vassas Toral, S. Geerts, Pierre Bommel, J. J. Vacher, François Léger, M. Chevarria Lazo, M. Vieira Pak, Muriel Tichit, Thierry Winkel, Jean-François Tourrand, Richard Joffre, Hector Daniel Bertero, Geneviève Cortes, Pierre Gasselin, and B. Martinez Avisa

Subjects
2. Zero hunger, Consumption (economics), Sociology of scientific knowledge, 010504 meteorology & atmospheric sciences, media_common.quotation_subject, Crop yield, Plant Science, 010501 environmental sciences, 15. Life on land, 01 natural sciences, Agricultural economics, Scarcity, Competition (economics), Agronomy, Soil retrogression and degradation, Sustainability, Economics, Production (economics), Agronomy and Crop Science, 0105 earth and related environmental sciences, media_common
Abstract

Reviewing the situation of quinoa production in southern Bolivia, Jacobsen (2011, J. Agron. Crop Sci. 197: 390) argues that the booming export market has a negative effect on the environment and on the home consumption of quinoa, thereby leading to an environmental disaster in the region. In view of the scarcity of scientific knowledge on the rapid social and environmental dynamics in the region, we consider that Jacobsen’s review misrepresents the situation of quinoa production in southern Bolivia. Specifically, we argue that (i) the data presented by Jacobsen (2011, J. Agron. Crop Sci. 197: 390) do not support any drop in quinoa crop yield supposed to reflect soil degradation and (ii) his demonstration regarding home consumption of quinoa is ill-founded from both a nutritional and a cultural point of view. We suggest that the diffusion of the arguments exposed by Jacobsen (2011, J. Agron. Crop Sci. 197: 390), because of their flaws, might have strong negative impacts on those concerned with sustainable food production and fair-trade with developing countries. We conclude that, rather than reinforced agro-technical controls on local farmers, the rising competition in the international quinoa market requires a shift towards an ethical economy and ethical research cooperation with quinoa producers.

Published
2012

25. Antioxidant and photoprotective responses to elevated CO2and heat stress during holm oak regeneration by resprouting, evaluated with NIRS (near-infrared reflectance spectroscopy)

Author

X. Aranda, Isidre Casals, M. Guàrdia, José Ignacio García-Plazaola, Richard Joffre, Isabel Fleck, Marta Pintó-Marijuan, Raquel Esteban, Massimo Zacchini, and M. De Agazio

Subjects
chemistry.chemical_classification, Stomatal conductance, food and beverages, Plant Science, General Medicine, Biology, Ascorbic acid, Photosynthesis, chemistry.chemical_compound, chemistry, Chlorophyll, Xanthophyll, Photoprotection, Botany, Photorespiration, Chlorophyll fluorescence, Ecology, Evolution, Behavior and Systematics
Abstract

Photosynthetic, photoprotective and antioxidant responses during high temperature stress were determined in leaves of evergreen holm oak (Quercus ilex L.), the main species in Mediterranean forests, during resprouting under elevated CO(2) (750 μl·l(-1) ). Leaf chemicals, chloroplast pigments and non-enzymatic antioxidants were quantified in a single measurement using NIRS (near-infrared spectroscopy), a rapid and suitable method for ecophysiological purposes. Resprouts from plants grown under elevated CO(2) (RE) showed photosynthetic down-regulation, higher starch content and lower stomatal conductance, but similar stomatal density, than plants grown under current CO(2) concentrations (350 μl·l(-1) ) (RA). The photosynthetic sink reduction and need for more antioxidants and photoprotection in RE were reflected in an increased concentration of ascorbate (Asc) and phenolic compounds and in the contribution of the xanthophyll (Z/VAZ) and lutein epoxide cycles to excess energy dissipation as heat, and also reflected in chlorophyll fluorescence measurements. CO(2) assimilation parameters were stable from 25 to 35 °C in RE and RA, declining thereafter in RA in spite of a 2.3 °C lower leaf temperature. RE showed a more marked decline in photorespiration above 35 °C and less sensitive stomatal responses to high temperature stress than RA. During heat stress, RE had higher Asc, Z/VAZ and phenolics content, together with delayed enhancement of chloroplast lipophilic antioxidant compounds (carotenes and tocopherols). The high contribution of photoprotective systems and high temperature tolerance in resprouts developed under elevated CO(2) would mitigate the effect of photosynthesis acclimation during the regeneration of Q. ilex plants under climate change.

Published
2012

26. Optimization criteria in sample selection step of local regression for quantitative analysis of large soil NIRS database

Author

Richard Joffre, Lionel Ranjard, Fabien Goge, Claudy Jolivet, I. Ross, Université de Montpellier (UM), InfoSol (InfoSol), Institut National de la Recherche Agronomique (INRA), Agroécologie [Dijon], and Institut National de la Recherche Agronomique (INRA)-Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement

Subjects
Soil test, Correlation coefficient, near infrared spectroscopy, [SDV]Life Sciences [q-bio], Fast Fourier transform, fast fourier transform, sample selection, 010501 environmental sciences, 01 natural sciences, Analytical Chemistry, Statistics, Partial least squares regression, soil spectral database, Spectroscopy, Selection (genetic algorithm), 0105 earth and related environmental sciences, Mathematics, compression methods, Mahalanobis distance, local calibration, business.industry, Process Chemistry and Technology, Local regression, Pattern recognition, 04 agricultural and veterinary sciences, 15. Life on land, Computer Science Applications, [SDE]Environmental Sciences, Principal component analysis, 040103 agronomy & agriculture, 0401 agriculture, forestry, and fisheries, Artificial intelligence, business, Software
Abstract

International audience; Large soil spectral libraries compiling thousands of NIR (Near Infrared) reflectance spectra have been created encompassing a wide diversity and heterogeneity of spectra. Among the many chemometric approaches to the calibration of chemical and physical properties from these large libraries, local calibrations have the advantage of being able to select the most similar spectra to the spectrum of a target sample. This is particularly relevant when dealing with highly heterogeneous media such as soils, where the mineral matrix has a strong influence on spectral features. A crucial step in the implementation of local calibration procedures is the construction of local neighbourhoods. In this study, we investigate the influence of index computation and neighbour selection on calibration results using local PLSR models on a large soil spectral database. Our indices combine two spectral compression methods (Principal Component Analysis or Fast Fourier Transform) with two distinct distance metrics (Mahalanobis distance or correlation coefficient). Based on a large collection of soil samples provided by the French National Soil Quality Monitoring programme, we constructed calibration models to estimate two chemical (organic carbon and cationic exchange capacity) and two physical (clay and sand content) factors. After neighbour selection, local Partial Least Squares regressions were applied to the selected spectra. Our results highlight the utility of the Fourier transformation of the spectra compared to the classical PCA compression method in achieving a more appropriate neighbourhood selection. We propose an index based on the coefficient correlation with FFT compression that led to a neighbourhood selection giving the best prediction results for the four considered soil constituents

Published
2012

27. Leaf CO2 efflux is attenuated by acclimation of respiration to heat and drought in a Mediterranean tree

Author

Serge Rambal, Jesús Rodríguez-Calcerrada, J. M. Limousin, Richard Joffre, Jean Marc Ourcival, and Carsten Jaeger

Subjects
0106 biological sciences, Mediterranean climate, Abiotic component, Canopy, Cellular respiration, 15. Life on land, Biology, Photosynthesis, Throughfall, 010603 evolutionary biology, 01 natural sciences, Acclimatization, Agronomy, 13. Climate action, Respiration, Ecology, Evolution, Behavior and Systematics, 010606 plant biology & botany
Abstract

Summary 1 Understanding the effect of water deficit on plant respiration and its temperature sensitivity at long time-scales is important for anticipating the shift in ecosystem dynamics that is expected to occur as a result of climate change. 2 We investigated seasonal variations of leaf dark respiration and sensitivity to temperature in the upper and lower canopy of Quercus ilex trees in a forest stand that had been exposed to either 33% throughfall reduction or normal rainfall for the preceding 6 years. 3 For upper and lower canopy leaves, light-saturated photosynthesis and respiration at a reference temperature of 15 °C (R15) had the lowest values in late summer, when both traits were lower in trees subjected to throughfall reduction than in those subject to control conditions. Respiration acclimated to seasonal shifts in temperature, more intensively through summer than winter and in throughfall-exclusion than control trees. Foliar concentration of soluble sugars was positively correlated with R15 across seasons. 4 As leaf respiration decreased with increasing water deficit, and the relationship between water status and respiration did not differ between trees that had been exposed to 7 years of enhanced drought when compared with controls, we suggest that drier conditions projected for the Mediterranean may attenuate the stimulation of leaf respiratory CO2 release by global warming in Q. ilex forests.

Published
2011

28. Ectomycorrhizal communities in a Mediterranean forest ecosystem dominated by Quercus ilex: seasonal dynamics and response to drought in the surface organic horizon

Author

Myriam Duchemin, Mélanie Roy, Oula Shahin, Christopher Sthultz, Richard Joffre, Marc-André Selosse, and Franck Richard

Subjects
0106 biological sciences, Mediterranean climate, Ecology, biology, Forest management, Forestry, 15. Life on land, biology.organism_classification, 010603 evolutionary biology, 01 natural sciences, Mediterranean Basin, Fagaceae, Ectomycorrhiza, Geography, [SDV.SA.SF]Life Sciences [q-bio]/Agricultural sciences/Silviculture, forestry, Forest ecology, Ecosystem, Mycorrhiza, ComputingMilieux_MISCELLANEOUS, 010606 plant biology & botany
Abstract

• Introduction Millions of hectares of Quercus ilex forests dominate disturbed landscapes in the western part of the Mediterranean basin. Although these forests are very widespread, little is known about the composition and structure of their associated ectomycorrhizal fungal communities.

Published
2011

29. Morphological and phenological shoot plasticity in a Mediterranean evergreen oak facing long-term increased drought

Author

Serge Rambal, Laurent Misson, Jean-Marc Ourcival, Ignacio Manuel Pérez-Ramos, Jesús Rodríguez-Calcerrada, Richard Joffre, Jean-Marc Limousin, and Raquel Rodrıguez-Cortina

Subjects
0106 biological sciences, Canopy, Biology, 010603 evolutionary biology, 01 natural sciences, Trees, Quercus, Botany, Leaf area index, Ecology, Evolution, Behavior and Systematics, Transpiration, Dehydration, Phenology, fungi, food and beverages, 15. Life on land, Plant litter, Evergreen, Throughfall, Droughts, Plant Leaves, Agronomy, Shoot, France, Plant Shoots, 010606 plant biology & botany
Abstract

Mediterranean trees must adjust their canopy leaf area to the unpredictable timing and severity of summer drought. The impact of increased drought on the canopy dynamics of the evergreen Quercus ilex was studied by measuring shoot growth, leaf production, litterfall, leafing phenology and leaf demography in a mature forest stand submitted to partial throughfall exclusion for 7 years. The leaf area index rapidly declined in the throughfall-exclusion plot and was 19% lower than in the control plot after 7 years of treatment. Consequently, leaf litterfall was significantly lower in the dry treatment. Such a decline in leaf area occurred through a change in branch allometry with a decreased number of ramifications produced and a reduction of the leaf area supported per unit sapwood area of the shoot (LA/SA). The leafing phenology was slightly delayed and the median leaf life span was slightly longer in the dry treatment. The canopy dynamics in both treatments were driven by water availability with a 1-year lag: leaf shedding and production were reduced following dry years; in contrast, leaf turnover was increased following wet years. The drought-induced decrease in leaf area, resulting from both plasticity in shoot development and slower leaf turnover, appeared to be a hydraulic adjustment to limit canopy transpiration and maintain leaf-specific hydraulic conductivity under drier conditions.

Published
2011
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30. Long-term transpiration change with rainfall decline in a MediterraneanQuercus ilexforest

Author

Richard Joffre, Jean-Marc Ourcival, R. Rodriguez-Cortina, Serge Rambal, Jean-Marc Limousin, and Alain Rocheteau

Subjects
Canopy, Hydrology, Global and Planetary Change, Water transport, Ecology, Throughfall, Water potential, Ecohydrology, Soil water, Environmental Chemistry, Environmental science, Leaf area index, General Environmental Science, Transpiration
Abstract

In the Mediterranean basin, precipitation is expected to decline as a consequence of climate change. The response of a Quercus ilex forest in southern France to such a decline in water availability was studied using a 4-year throughfall exclusion experiment. Seasonal courses of sap flow and leaf water potential were obtained from 2004 to 2007 and used to characterize tree water relations in a control and a dry treatment. The experiment reduced the average precipitation input to the soil by 29%, and resulted in a 23% reduction in annual transpiration. Soil water potential was significantly lower in the dry treatment only during summer drought, but transpiration was reduced all year round even during well-watered periods. Despite a tight stomatal control over transpiration, whole-tree hydraulic conductance was found to be lower in the trees growing in the driest conditions. This reduction in water transport capacity was observed jointly with a reduction in leaf transpiring area. Canopy leaf area decreased by 18% in the dry treatment as a consequence of the throughfall exclusion, which was found to validate the ecohydrological equilibrium theory.

Published
2009

31. Calibration of Chemical and Biological Changes in Cocomposting of Biowastes Using Near-Infrared Spectroscopy

Author

Gérard Terrom, Remy Albrecht, Richard Joffre, Jean Petit, and Claude Périssol

Subjects
chemistry.chemical_classification, Spectroscopy, Near-Infrared, Sewage, biology, Chemistry, Compost, Near-infrared spectroscopy, Inorganic chemistry, chemistry.chemical_element, General Chemistry, Cellulase, engineering.material, Nitrogen, Oxygen, Soil, Environmental chemistry, Calibration, biology.protein, engineering, Environmental Chemistry, Humic acid, Degradation (geology), Organic matter, Sludge
Abstract

Cocomposting of green wastes and sewage sludges is a complex process involving rapid biological and chemical changes. The objective of the study was to assess the usefulness of near-infrared reflectance spectroscopy (NIRS) to characterize these changes, as an alternative to standard procedures which are often time-consuming and laborious. Samples obtained during 146 days of composting were analyzed by 14 conventional methods and NIRS. Results from conventional methods demonstrated a noticeable separation into two distinct phases. An initial phase from 4 to 50-60 days was characterized by intensive degradation. A second phase up to 146 days was characterized by a decrease in all biological activities. NIRS calibrations allowed accurate predictions of nitrogen (N), carbon (C), C/N, humic acid (HA), pH, respiration, cellulase, phenoloxidase, and composting time successfully. Results were less accurate for organic matter (OM), protease, acid, and alkaline phosphatases and unsatisfactory for fulvic acid. NIRS calibration allows composting time/state of progress of maturation to be predicted accurately to within 10 days. A global index of composting evolution (GICE), resulting from the 14 parameters studied, is proposed. It is precisely predicted and shows that since NIRS is able to predict essential parameters of compost maturity, it could prove invaluable for monitoring biowastes cocomposting.

Published
2008

32. Do volatile organic compound emissions of Tunisian cork oak populations originating from contrasting climatic conditions differ in their responses to summer drought?

Author

Amel Ennajah, Michael Staudt, Florent Mouillot, and Richard Joffre

Subjects
chemistry.chemical_classification, Global and Planetary Change, education.field_of_study, Ecology, Ecotype, biology, Phenology, Population, Forestry, Quercus suber, Photosynthesis, biology.organism_classification, Arid, chemistry.chemical_compound, chemistry, Chlorophyll, Botany, Volatile organic compound, education
Abstract

The intrinsic variability of volatile organic compound emissions and photosynthetic parameters in response to two drying cycles was investigated on Quercus suber L. saplings originating from three Tunisian populations native to contrasting climates. Emissions mainly included monoterpenes plus traces of sesquiterpenes and methylsalicylate that steadily decreased during the experiment unrelated to treatments. Instead, monoterpene emissions increased by 30% during a first moderate drought and remained enhanced after rewatering, while CO2-H2O gas exchange was reduced by 30%. A second severe drought decreased monoterpene emissions to about two third of controls, strongly inhibited gas exchange and photochemical efficiency, and caused a partial loss of chlorophyll. Rewatering led to only partial recovery of emis- sions and photosynthetic parameters of stressed plants whose biomasses and leaf nitrogen and chlorophyll contents were lower than in control plants. There was no clear difference among populations in volatile organic compound emissions or photosynthetic parameters. However, the population inhabiting the most arid region had intrinsically smaller leaves with lower specific leaf masses and higher drought-related leaf losses than populations native to less arid climates. These results indicate an adaptive shift from stress-tolerating towards stress-avoiding ecotypes under arid climates involving mainly mor- phological adaptations without apparent differentiation in volatile organic compound production, probably because of its high phenological plasticity. Resume´ : La variabilitedes emissions foliaires de composes organiques volatils et des parametres photosynthetiques ont eteetudies au cours de deux cycles de dessechement sur des plants de Quercus suber L. provenant de trois populations tu- nisiennes adaptees a des differentes conditions climatiques. Les composes organiques volatils emis etaient principalement des monoterpenes, plus, independamment du traitement, des traces de sesquiterpenes et methyle-salicylate. Un premier des- sechement moderereduisant les echanges gazeux en CO2-H2O de 30%, a augmentede 30% les emissions de composes organiques volatils qui sont restees elevees apresr ehydratation. Un second dessechement plus severe a reduit les emissions d'environ 30% accompagned'une forte inhibition des echanges gazeux et de l'efficience photochimique et d'une perte partielle de chlorophylle. Apresr ehydratation les emissions et les parametres photosynthetiques ont partiellement recupere´. Les biomasses aeriennes et souterraines finales ainsi que l'azote foliaire et la teneur en chlorophylle des plantes stressees etaient inferieurs a ceux des temoins. Les emissions de composes organiques volatils et les parametres photosynthetiques n'etaient pas nettement differents entre populations. Cependant, la population provenant du site le plus aride presentait des feuilles plus petites de poids specifique plus faible, et des pertes de feuilles plus importantes apres le stress que les popula- tions adaptees a des sites moins arides. Ces resultats pourraient indiquer l'evolution adaptative d'une strategie de tolerance au stress vers une strategie d'evitement du stress sous climat aride impliquant surtout des adaptations morphologiques sans difference apparente dans la production de composes organiques volatils, probablement a cause d'une grande plasticite´ phenologique.

Published
2008

33. Modelling rainfall interception in a mediterranean Quercus ilex ecosystem: Lesson from a throughfall exclusion experiment

Author

Jean-Marc Ourcival, Richard Joffre, Jean-Marc Limousin, and Serge Rambal

Subjects
Canopy, Hydrology, Stemflow, Soil water, Environmental science, Precipitation, Interception, Leaf area index, Throughfall, Water Science and Technology, Basal area
Abstract

Summary In the Mediterranean basin, precipitation is expected to decline by the end of the 21st century as a consequence of climate change. A throughfall exclusion experiment has been established in a Quercus ilex coppice in southern France to anticipate the response of this ecosystem to a reduced precipitation amount by removing part of the throughfall. The experiment involved four 140 m2 plots: a control plot, a throughfall exclusion plot, a thinned plot and a throughfall exclusion in a thinned plot. This experiment has been used during nearly two years to monitor throughfall amounts in the different plots. Additionally, stemflow has been recorded on 20 trees between 25 April 2006 and 15 May 2007. The control plot had a stem density of 6885 stems ha−1 and a leaf area index of 3.1, rainfall partitioning into interception loss, throughfall and stemflow was, respectively, 30.9%, 56.6% and 12.5% of the total precipitation (1605 mm over the study period). Thinning reduced the stem basal area by 33% and the total interception loss by 34.6%. Given the rainfall partitioning, the throughfall exclusion was found to remove 19% of total precipitation, which was confirmed by soil water content measurements. The revised Gash analytical model predicted interception with an agreement of −6.2% of total precipitation. Results show a good transferability of the model to a plot with a different stem density, thus supporting the idea that model parameters and evaporation from a wet canopy scale linearly with canopy cover.

Published
2008

34. Seasonal and annual variation of carbon exchange in an evergreen Mediterranean forest in southern France

Author

Serge Rambal, Vincent Allard, Richard Joffre, Alain Rocheteau, and Jean-Marc Ourcival

Subjects
0106 biological sciences, Mediterranean climate, Global and Planetary Change, 010504 meteorology & atmospheric sciences, Ecology, Eddy covariance, Primary production, 15. Life on land, Seasonality, Evergreen, Atmospheric sciences, medicine.disease, 01 natural sciences, Evergreen forest, 13. Climate action, medicine, Environmental Chemistry, Environmental science, Ecosystem, Ecosystem respiration, 010606 plant biology & botany, 0105 earth and related environmental sciences, General Environmental Science
Abstract

We present 9 years of eddy covariance measurements made over an evergreen Mediterranean forest in southern France. The goal of this study was to quantify the different components of the carbon (C) cycle, gross primary production (GPP) and ecosystem respiration (R-eco), and to assess the effects of climatic variables on these fluxes and on the net ecosystem exchange of carbon dioxide. The Puechabon forest acted as a net C sink of -254 g C m(-2) yr(-1), with a GPP of 1275 g C m(-2) yr(-1) and a R-eco of 1021 g C m(-2) yr(-1). On average, 83% of the net annual C sink occurred between March and June. The effects of exceptional events such the insect-induced partial canopy defoliation that occurred in spring 2005, and the spring droughts of 2005 and 2006 are discussed. A high interannual variability of ecosystem C fluxes during summer and autumn was observed but the resulting effect on the annual net C budget was moderate. Increased severity and/or duration of summer drought under climate change do not appear to have the potential to negatively impact the average C budget of this ecosystem. On the contrary, factors affecting ecosystem functioning (drought and/or defoliation) during March-June period may reduce dramatically the annual C balance of evergreen Mediterranean forests.

Published
2008

35. Growth duration is a better predictor of stem increment than carbon supply in a mediterranean oak forest: implications for assessing forest productivity under climate change

Author

Richard Joffre, Serge Rambal, Morine Lempereur, Claire Damesin, Alain Rocheteau, Jean-Marc Ourcival, Nicolas Martin-StPaul, Centre d’Ecologie Fonctionnelle et Evolutive (CEFE), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Université Paul-Valéry - Montpellier 3 (UPVM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut de Recherche pour le Développement (IRD [France-Sud]), Agence de l'Environnement et de la Maîtrise de l'Energie (ADEME), Ecologie des Forêts Méditerranéennes (URFM), Institut National de la Recherche Agronomique (INRA), Ecologie Systématique et Evolution (ESE), Université Paris-Sud - Paris 11 (UP11)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS), Universidade Federal de Lavras (UFLA), and This work was supported by the French Environment and Energy Management Agency (ADEME) and the DROUGHT+ (ANR-06-VULN-003-01). Additional support was provided by CARBO-Extreme (FP7-ENV-2008-1-226701)

Subjects
0106 biological sciences, Mediterranean climate, Time Factors, 010504 meteorology & atmospheric sciences, Physiology, Rain, [SDE.MCG]Environmental Sciences/Global Changes, Eddy covariance, Climate change, tree water relation, Plant Science, drought, Forests, Atmospheric sciences, 01 natural sciences, Basal area, Trees, Coppicing, Quercus, Effects of global warming, Ecosystem, Photosynthesis, quercus ilex, extreme event, 0105 earth and related environmental sciences, water deficit, Population Density, Plant Stems, Phenology, Ecology, Mediterranean Region, Water, 15. Life on land, vegetation models, Carbon, Quercus ilex, climate change, 13. Climate action, Environmental science, Seasons, carbon partitioning, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, 010606 plant biology & botany
Abstract

International audience; Understanding whether tree growth is limited by carbon gain (source limitation) or by the direct effect of environmental factors such as water deficit or temperature (sink limitation) is crucial for improving projections of the effects of climate change on forest productivity. We studied the relationships between tree basal area (BA) variations, eddy covariance carbon fluxes, predawn water potential ((pd)) and temperature at different timescales using an 8-yr dataset and a rainfall exclusion experiment in a Quercus ilex Mediterranean coppice. At the daily timescale, during periods of low temperature (

Published
2015

36. El presunto desastre ambiental y social de la quinua real: desarmar los clichés para reforzar la ética

Author

Thierry Winkel, Pablo Cruz, Ricardo Alvarez-Flores, Daniel Bertero, Carmen del Castillo, Pierre Gasselin, Richard Joffre, Santiago Peredo Parada, Luis Sáez Tonacca, Anaïs Vassas Toral, Manuela Viera-Pako, Centre d’Ecologie Fonctionnelle et Evolutive (CEFE), Université Paul-Valéry - Montpellier 3 (UPVM)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Institut de Recherche pour le Développement (IRD), Consejo Nacional de Investigaciones Científicas y Técnicas, Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Université Paul-Valéry - Montpellier 3 (UPVM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut de Recherche pour le Développement (IRD [France-Sud]), Instituto de Investigaciones Fisiologicas y Ecologicas Vinculadas a la Agricultura (IFEVA), Facultad de Agronomía [Buenos Aires], Universidad de Buenos Aires [Buenos Aires] (UBA)-Universidad de Buenos Aires [Buenos Aires] (UBA)-Consejo Nacional de Investigaciones Científicas y Técnicas [Buenos Aires] (CONICET), Facultad de Agronomia, Universidad Mayor de San Andrés (UMSA), Innovation et Développement dans l'Agriculture et l'Alimentation (UMR Innovation), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Universidad de Santiago de Chile [Santiago] (USACH), Acteurs, Ressources et Territoires dans le Développement (UMR ART-Dev), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Université Paul-Valéry - Montpellier 3 (UPVM)-Université de Perpignan Via Domitia (UPVD)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), consultant, ANR-06-PADD-11-EQUECO, ECOS-Sud A11B03, PCCI-2012 12051, Université Paul-Valéry - Montpellier 3 (UPVM)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-École Pratique des Hautes Études (EPHE), Consejo Nacional de Investigaciones Científicas y Técnicas [Buenos Aires] (CONICET)-Facultad de Agronomía [Buenos Aires], Universidad de Buenos Aires [Buenos Aires] (UBA)-Universidad de Buenos Aires [Buenos Aires] (UBA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Université Paul-Valéry - Montpellier 3 (UPVM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Institut de Recherche pour le Développement (IRD [France-Sud]), and Centre National de la Recherche Scientifique (CNRS)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Université de Montpellier (UM)-Université de Perpignan Via Domitia (UPVD)-Université Paul-Valéry - Montpellier 3 (UPVM)

Subjects
quinua, agricultural sustainability, preconception, [SDV]Life Sciences [q-bio], technoscience, ethics, [SHS]Humanities and Social Sciences
Abstract

International audience; The quinoa boom has provoked a lively debate about its social and ecological impacts in the southern Bolivian highlands, the world's leading export zone. An interdisciplinary analysis puts in perspective those changes seen in the last 40 years. While acknowledging the need for further support to local agrarian dynamics around quinoa production, we challenge affirmations about its unsustainability in southern Bolivia.; El auge de la quinua genera un vivo debate sobre sus impactos sociales y ecológicos en el altiplano sur de Bolivia, primer exportador mundial. Un análisis interdisciplinario permite poner en perspectiva los cambios ocurridos desde hace más de 40 años. Sin negar la necesidad de un apoyo a las dinámicas agrarias locales en torno a la quinua, se contestan aquellas afirmaciones que aseguran la insustentabilidad de la producción en el sur de Bolivia.

Published
2015

37. Interpreting canopy development and physiology using the EUROPhen camera network at flux sites

Author

Juan Alberto Porcar Castell, Dan Yakir, Olaf Kolle, James I. L. Morison, Bernard Genty, Lukas Hörtnagl, Alexander Knohl, Pasi Kolari, Richard Joffre, Werner Eugster, Cristina Gimeno, Christophe Moisy, Bernard Heinesch, Lisa Wingate, Edoardo Cremonese, Tatsuro Nakaji, Werner L. Kutsch, Christine Moreaux, Barbara Köstner, Bert Gielen, Manuela Balzarolo, Dominique Guyon, Marta Galvagno, Thomas Grünwald, Georg Wohlfahrt, Janne Levula, Anders Lindroth, Toshie Mizunuma, Dario Papale, Georg Charles, Jean-Marc Ourcival, Mirco Migliavacca, Andreas Ibrom, Matthew Wilkinson, Tanguy Manise, Eero Nikinmaa, Gianluca Filippa, Katja Klumpp, Margareta Hellström, Andres Plaza-Aguilar, Hella Ellen Ahrends, John Grace, Jérôme Ogée, Jin-Hong Guan, Bernard Longdoz, Michael Sprintsin, Department of Forest Sciences, Department of Physics, Eero Nikinmaa / Principal Investigator, Viikki Plant Science Centre (ViPS), Ecosystem processes (INAR Forest Sciences), Micrometeorology and biogeochemical cycles, and Forest Ecology and Management

Subjects
Canopy, Hydrology, 4112 Forestry, Phenology, education, Growing season, Vegetation, 15. Life on land, Evergreen, Atmospheric sciences, 114 Physical sciences, Deciduous, 13. Climate action, Environmental science, Ecosystem, Segmented regression
Abstract

Plant phenological development is orchestrated through subtle changes in photoperiod, temperature, soil moisture and nutrient availability. Presently, the exact timing of plant development stages and their response to climate and management practices are crudely represented in land surface models. As visual observations of phenology are laborious, there is a need to supplement long-term observations with automated techniques such as those provided by digital repeat photography at high temporal and spatial resolution. We present the first synthesis from a growing observational network of digital cameras installed on towers across Europe above deciduous and evergreen forests, grasslands and croplands, where vegetation and atmosphere CO2 fluxes are measured continuously. Using colour indices from digital images and using piecewise regression analysis of time-series, we explored whether key changes in canopy phenology could be detected automatically across different land use types in the network. The piecewise regression approach could capture the start and end of the growing season, in addition to identifying striking changes in colour signals caused by flowering and management practices such as mowing. Exploring the dates of green up and senescence of deciduous forests extracted by the piecewise regression approach against dates estimated from visual observations we found that these phenological events could be detected adequately (RMSE < 8 and 11 days for leaf out and leaf fall respectively). We also investigated whether the seasonal patterns of red, green and blue colour fractions derived from digital images could be modelled mechanistically using the PROSAIL model parameterised with information of seasonal changes in canopy leaf area and leaf chlorophyll and carotenoid concentrations. From a model sensitivity analysis we found that variations in colour fractions, and in particular the late spring "green hump" observed repeatedly in deciduous broadleaf canopies across the network, are essentially dominated by changes in the respective pigment concentrations. Using the model we were able to explain why this spring maximum in green signal is often observed out of phase with the maximum period of canopy photosynthesis in ecosystems across Europe. Coupling such quasi-continuous digital records of canopy colours with co-located CO2 flux measurements will improve our understanding of how changes in growing season length are likely to shape the capacity of European ecosystems to sequester CO2 in the future.

Published
2015

38. Modelling the climatic drivers determining photosynthesis and carbon allocation in evergreen Mediterranean forests using multiproxy long time series

Author

Guillaume Simioni, Richard Joffre, Jean-Marc Ourcival, Frédéric Guibal, Guillermo Gea-Izquierdo, Joel Guiot, Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Collège de France (CdF)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Institut National de la Recherche Agronomique (INRA), Institut méditerranéen de biodiversité et d'écologie marine et continentale (IMBE), Avignon Université (AU)-Aix Marseille Université (AMU)-Institut de recherche pour le développement [IRD] : UMR237-Centre National de la Recherche Scientifique (CNRS), Centre d’Ecologie Fonctionnelle et Evolutive (CEFE), Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE)-Université de Montpellier (UM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Université Paul-Valéry - Montpellier 3 (UM3), Ecologie des Forêts Méditerranéennes [Avignon] (URFM 629), Institut National de la Recherche Agronomique (INRA), ANR-11-LABX-0010/11-LABX-0010,LabEx DRIIHM,Dispositif de recherche interdisciplinaire sur les Interactions Hommes-Milieux(2011), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), Centre National de la Recherche Scientifique (CNRS)-Institut de recherche pour le développement [IRD] : UMR237-Aix Marseille Université (AMU)-Avignon Université (AU), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Université Paul-Valéry - Montpellier 3 (UPVM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut de Recherche pour le Développement (IRD [France-Sud]), Ecologie des Forêts Méditerranéennes (URFM), G. Gea-Izquierdo was funded by the Labex OT-Med (no. ANR-11-LABEX-0061) from the 'Investissements d'Avenir' program of the French National Research Agency through the A*MIDEX project (no. ANR-11-IDEX-0001-02). Federation de Recherche FR3098 ECCOREV, the labex IRDHEI and OHM-BMP also supported the study., ANR-11-LABX-0010,DRIIHM / IRDHEI,Dispositif de recherche interdisciplinaire sur les Interactions Hommes-Milieux(2011), Gea-Izquierdo, Guillermo, Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Paul-Valéry - Montpellier 3 (UPVM)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-École Pratique des Hautes Études (EPHE), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)

Subjects
Canopy, 0106 biological sciences, 010504 meteorology & atmospheric sciences, Biodiversité et Ecologie, lcsh:Life, Atmospheric sciences, 01 natural sciences, CRITICAL-APPRAISAL, QUERCUS-ILEX, ATMOSPHERIC CO2 CONCENTRATIONS, FAGUS-SYLVATICA, quercus ilex, pinus halepensis, sud de la france, TREE-GROWTH, dynamique du carbone, Ecology, [SDE.IE]Environmental Sciences/Environmental Engineering, Provence mining area, lcsh:QE1-996.5, forêt méditerranéenne, facteur climatique, SEVERE DROUGHT, [SDE]Environmental Sciences, WATER-USE EFFICIENCY, Stomatal conductance, [SDE.MCG]Environmental Sciences/Global Changes, Eddy covariance, Climate change, Biodiversity and Ecology, lcsh:QH540-549.5, LabEx DRIIHM, Ecosystem, conductance stomatique, photosynthèse, Leaf area index, SCOTS PINE, Ecology, Evolution, Behavior and Systematics, Earth-Surface Processes, modélisation, 0105 earth and related environmental sciences, Forest inventory, OHM Bassin Minier de Provence, Evergreen, quercus coccifera, 15. Life on land, lcsh:Geology, lcsh:QH501-531, OAK WOODLANDS, Observatoires Hommes-Millieux, 13. Climate action, Environmental science, ECOSYSTEM, lcsh:Ecology, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, 010606 plant biology & botany
Abstract

Climatic drivers limit several important physiological processes involved in ecosystem carbon dynamics including gross primary productivity (GPP) and carbon allocation in vegetation. Climatic variability limits these two processes differently. We developed an existing mechanistic model to analyse photosynthesis and variability in carbon allocation in two evergreen species at two Mediterranean forests. The model was calibrated using a combination of eddy covariance CO2 flux data, dendrochronological time series of secondary growth and forest inventory data. The model was modified to be climate explicit in the key processes addressing the acclimation of photosynthesis and the pattern of C allocation, particularly to water stress. It succeeded in fitting both the high- and the low-frequency response of stand GPP and carbon allocation to stem growth. This would support its capability to address both C-source and C-sink limitations. Simulations suggest a decrease in mean stomatal conductance in response to a recent enhancement in water stress and an increase in mean annual intrinsic water use efficiency (iWUE) in both species during the last 50 years. However, this was not translated into a parallel increase in ecosystem water use efficiency (WUE). The interannual variability in WUE closely followed that in iWUE at both sites. Nevertheless, long-term decadal variability in WUE followed the long-term decrease in annual GPP matching the local trend in annual precipitation observed since the late 1970s at one site. In contrast, at the site where long-term precipitation remained stable, GPP and WUE did not show a negative trend and the trees buffered the climatic variability. In our simulations these temporal changes were related to acclimation processes at the canopy level, including modifications in LAI and stomatal conductance, but also partly related to increasing [CO2] because the model includes biochemical equations where photosynthesis is directly linked to [CO2]. Long-term trends in GPP did not match those in growth, in agreement with the C-sink hypothesis. The model has great potential for use with abundant dendrochronological data and analyse forest performance under climate change. This would help to understand how different interfering environmental factors produce instability in the pattern of carbon allocation and, hence, the climatic signal expressed in tree rings.

Published
2015

39. Sostenibilidad de la producción de quinua en el Altiplano Sur de Bolivia: un enfoque desde la panarquía

Author

Thierry Winkel, Pierre Pommel, Jean Bourliaud, Marco Allan Chevarria Lazo, Geneviève Cortes, Pierre Gasselin, Richard Joffre, Francois Leger, Serge Rambla, Gilles Rivière, Muriel Tichit, Jean-François Tourrand, Anaïs Vassas, Manuela Veira Pak, Centre d’Ecologie Fonctionnelle et Evolutive (CEFE), Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE)-Université de Montpellier (UM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Université Paul-Valéry - Montpellier 3 (UM3), Unité de recherche Paysannerie, Territoires, Environnement, Marchés et politiques Publiques (MONA), Institut National de la Recherche Agronomique (INRA), Acteurs, Ressources et Territoires dans le Développement (UMR ART-Dev), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Paul-Valéry - Montpellier 3 (UM3)-Université de Perpignan Via Domitia (UPVD)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad), Innovation et Développement dans l'Agriculture et l'Alimentation (UMR Innovation), Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad), Sciences pour l'Action et le Développement : Activités, Produits, Territoires (SADAPT), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, Mondes Américains (CERMA), Université Panthéon-Sorbonne (UP1)-Université Paris Nanterre (UPN)-Centre National de la Recherche Scientifique (CNRS)-École des hautes études en sciences sociales (EHESS), Gestion des ressources renouvelables et environnement (Cirad-Es-UPR 47 GREEN), Département Environnements et Sociétés (Cirad-ES), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad), ANR-06-PADD-011-EQUECO, Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Université Paul-Valéry - Montpellier 3 (UPVM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut de Recherche pour le Développement (IRD [France-Sud]), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Université Paul-Valéry - Montpellier 3 (UPVM)-Université de Perpignan Via Domitia (UPVD)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Université Paris 1 Panthéon-Sorbonne (UP1)-École des hautes études en sciences sociales (EHESS)-Université Paris Nanterre (UPN)-Centre National de la Recherche Scientifique (CNRS), Gestion des ressources renouvelables et environnement (UPR GREEN), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad), Centre National de la Recherche Scientifique (CNRS)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Université de Montpellier (UM)-Université de Perpignan Via Domitia (UPVD)-Université Paul-Valéry - Montpellier 3 (UPVM), AgroParisTech-Institut National de la Recherche Agronomique (INRA), Université Paul-Valéry - Montpellier 3 (UM3)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-École pratique des hautes études (EPHE)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), and Université Panthéon-Sorbonne (UP1)-École des hautes études en sciences sociales (EHESS)-Université Paris Nanterre (UPN)-Centre National de la Recherche Scientifique (CNRS)

Subjects
quinua, [SDV]Life Sciences [q-bio], sostenibilidad, bolivia
Abstract

Capitulo 10; Sostenibilidad de la producción de quinua en el Altiplano Sur de Bolivia: un enfoque desde la panarquía

Published
2015

40. Partitioning energy and evapo-transpiration above and below a tropical palm canopy

Author

Christophe Jourdan, Jean Dauzat, Jean-Pierre Bouillet, André Rouzière, Jean-Pierre Labouisse, Muriel Navarro, M. Irvine, Isabelle Mialet-Serra, Serge Braconnier, Laurent Saint-André, Daniel Epron, Yann Nouvellon, Olivier Roupsard, Olivier Hamel, Paul Berbigier, Serge Taga, Richard Joffre, Jean-Marc Bonnefond, Botanique et Modélisation de l'Architecture des Plantes et des Végétations (UMR AMAP), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), and Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de la Recherche Agronomique (INRA)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut de Recherche pour le Développement (IRD [France-Sud])

Subjects
0106 biological sciences, Canopy, Atmospheric Science, F40 - Écologie végétale, 010504 meteorology & atmospheric sciences, Vapour Pressure Deficit, F60 - Physiologie et biochimie végétale, Energy balance, Teneur en eau, Sensible heat, Atmospheric sciences, 01 natural sciences, Eddy-correlation, [SDV.BV]Life Sciences [q-bio]/Vegetal Biology, Agroforestry, Leaf area index, Bowen ratio, Compétition biologique, Cocos nucifera L, Cocos nucifera, 0105 earth and related environmental sciences, Transpiration, Hydrology, Global and Planetary Change, Érosion, U10 - Informatique, mathématiques et statistiques, Energy balance closure, Forestry, 15. Life on land, Évapotranspiration, Canopy conductance, Physiologie végétale, Sapflow calibration, Environmental science, Agronomy and Crop Science, 010606 plant biology & botany
Abstract

For open canopies, the partitioning of energy and water fluxes between the upper canopy and the under-storey is key to understand the competition mechanisms between layers. We monitored stand evapo-transpiration by eddy-covariance (E), tree transpiration (T) by heat-dissipative sapflow, soil (G) and stand (J) heat storage during 3 years in a typical coconut palm row-plantation of the humid tropics, displaying a constant leaf area index (LAI = 3) and a grass under-storey. A two-level flux experiment yielded cross-validation of the evapo-transpiration of the under-storey (Eu) with E - T, through energy balance closure for E and sapflow calibration in the laboratory for T. On a yearly time step, E represented 40% of rainfall, the sensible heat flux (H) was 26% of net radiation and the Bowen ratio was 0.39, all indicating that water availability was close-to-optimum. T represented 68% of E, close to the 75% of soil coverage by palms. The inter-annual variability was low for potential evapo-transpiration (ETo), energy and water fluxes. The seasonal variability was more pronounced, driven by radiation and vapour pressure deficit (VPD). The canopy conductance of coconut palms appeared to be strongly controlled by VPD. Given its constant LAI, its continuous growth and its simple architecture, the coconut palm appears to be an ideal candidate for physiological work and agroforestry modelling. © 2006 Elsevier B.V. All rights reserved.

Published
2006

41. Photosynthesis, growth and structural characteristics of holm oak resprouts originated from plants grown under elevated CO2

Author

Isabel Fleck, Cristina Agustí, Xavier Aranda, and Richard Joffre

Subjects
Stomatal conductance, biology, Photosystem II, Physiology, Chemistry, RuBisCO, food and beverages, Cell Biology, Plant Science, General Medicine, Photosynthesis, Photosynthetic capacity, chemistry.chemical_compound, Chlorophyll, Botany, Genetics, biology.protein, Chlorophyll fluorescence, Photosystem
Abstract

The physiological characteristics of holm oak (Quercus ilex L.) resprouts originated from plants grown under current CO2 concentration (350 μl l−1) (A-resprouts) were compared with those of resprouts originated from plants grown under elevated CO2 (750 μl l−1) (E-resprouts). At their respective CO2 growth concentration, no differences were observed in photosynthesis and chlorophyll fluorescence parameters between the two kinds of resprout. E-resprouts appeared earlier and showed lower stomatal conductance, higher water-use efficiency and increased growth (higher leaf, stem and root biomass and increased height). Analyses of leaf chemical composition showed the effect of elevated [CO2] on structural polysaccharide (higher cellulose content), but no accumulation of total non-structural carbohydrate on area or dry weight basis was seen. Four months after appearance, downregulation of photosynthesis and electron transport components was observed in E-resprouts: lower photosynthetic capacity, photosystem II quantum efficiency, photochemical quenching of fluorescence and relative electron transport rate. Reduction in ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCo) activity, deduced from the maximum carboxylation velocity of RuBisCo, accounts for the observed acclimation. Increased susceptibility of photosynthetic apparatus to increasing irradiance was detected in E-resprouts.

Published
2006

42. Quantifying species composition in root mixtures using two methods: near‐infrared reflectance spectroscopy and plant wax markers

Author

Catherine Roumet, Alain Blanchard, Catherine Picon-Cochard, Mark J. Brewer, Richard Joffre, Lorna Dawson, Robert W. Mayes, Centre d’Ecologie Fonctionnelle et Evolutive (CEFE), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Université Paul-Valéry - Montpellier 3 (UPVM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut de Recherche pour le Développement (IRD [France-Sud]), UR 0874 Unité de recherche Agronomie de Clermont, Institut National de la Recherche Agronomique (INRA)-Environnement et Agronomie (E.A.)-Ecologie des Forêts, Prairies et milieux Aquatiques (EFPA), Institut National de la Recherche Agronomique (INRA)-Unité de recherche Agronomie de Clermont (URAC), Macaulay Land Use Research Institute, and Partenaires INRAE

Subjects
0106 biological sciences, Physiology, PLANT WAX MARKER, Reflectance spectroscopy, Analytical chemistry, ALCOHOL, Plant Science, Plant Roots, 01 natural sciences, Species Specificity, ROOT, ALKANE, Alkanes, Botany, Biomass, Spectral data, NEAR-INFRARED REFLECTANCE SPECTROSCOPY, Alkane, chemistry.chemical_classification, Wax, Spectroscopy, Near-Infrared, RAY GRASS ANGLAIS, BOTANICAL COMPOSITION, 04 agricultural and veterinary sciences, Herbaceous plant, HERBACEOUS SPECIES, HOLCUS LANATUS, [SDV.BV.PEP]Life Sciences [q-bio]/Vegetal Biology/Phytopathology and phytopharmacy, NIRS, chemistry, Waxes, visual_art, 040103 agronomy & agriculture, visual_art.visual_art_medium, 0401 agriculture, forestry, and fisheries, SPECTROSCOPIE INFRAROUGE, Composition (visual arts), Near infrared reflectance spectroscopy, Fatty Alcohols, Multivariate statistical, Biomarkers, 010606 plant biology & botany
Abstract

International audience; Understanding of plant interactions is greatly limited by our ability to identify and quantify roots belonging to different species. We proposed and compared two methods for estimating the root biomass proportion of each species in artificial mixtures: near-infrared reflectance spectroscopy (NIRS) and plant wax markers. Two sets of artificial root mixtures composed of two or three herbaceous species were prepared. The proportion of root material of each species in mixtures was estimated from NIRS spectral data (i) and the concentration patterns of n-alkanes (ii), n-alcohols (iii), and n-alkanes +n-alcohols combined (iv). For each data set, calibration equations were developed using multivariate statistical models. The botanical composition of root mixtures was predicted well for all the species considered. The accuracy varied slightly among methods: alkanes < alcohols = alkanes + alcohols < NIRS. Correlation coefficients between predicted and actual root proportions ranged from 0.89 to 0.99 for alkanes + alcohols predictions and from 0.97 to 0.99 for NIRS predictions. These two methods provide promising potential for understanding allocation patterns and competitive interactions.

Published
2006

43. Evaluating soil quality in tropical agroecosystems of Colombia using NIRS

Author

Patrick Lavelle, Richard Joffre, Edmundo Barrios, and Elena Velasquez

Subjects
AGRICULTURE, respirometry, RESPIROMETRIE, Soil Science, Mineralogy, Microbiology, near infrared reflectance spectroscopy, Soil management, EVOLUTION DES SOLS SOUS CULTURE, Organic matter, soil quality, soil differentiation, chemistry.chemical_classification, METHODE D'ANALYSE, SOL, SPECTROMETRIE INFRAROUGE, Soil organic matter, MATIERE ORGANIQUE, ETUDE D'IMPACT, Linear discriminant analysis, Soil quality, chemistry, Environmental chemistry, Soil water, Principal component analysis, Environmental science, QUALITE DU SOL, Soil fertility, organic fractions
Abstract

Near infrared reflectance spectroscopy (NIRS) analysis was used to discriminate soils of different agroecosystems in Colombia, with different contents and qualities of organic matter, chemical, and biological properties. Correlations were sought between absorbance in wavelength classes as determined by NIRS, and a set of variables describing soil quality grouped into three classes: (i) chemical variables (Ca, Mg, K, exchangeable Al, total P, P-Bray II); (ii) organic variables (total C, total N, N - NH4+, N - NO3-, respirometry and carbon content in different fractions separated by the LUDOX physical methods) and (iii) NIRS variables quantifying the absorptions in the near infrared region separated into 101 classes of wavelength). For each group of variables, a principal component analysis (PCA), associated with discriminant analysis, was run. Each class of variables separated the different soil-use systems (***P < 0.001) similarly. Co-inertia analyses among the different groups of variables verified the sensitivity of the NIRS in detecting significant changes in the soil chemical and organic composition, as well as in microbial activity. These results show the high potential of the NIRS for evaluating soil quality in large areas, rapidly, reliably and economically, thereby facilitating decision-making with respect to soil management and conservation. (c) 2004 Published by Elsevier Ltd.

Published
2005

44. Spatial and temporal variations of soil respiration in a Eucalyptus plantation in Congo

Author

Christophe Jourdan, Welcome J. Mouvondy, Richard Joffre, Daniel Epron, Olivier Roupsard, Yann Nouvellon, Paul Berbigier, Laurent Saint-André, Jean-Marc Bonnefond, Olivier Hamel, André Mabiala, Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC), Unité de recherche sur la productivité des plantations industrielles, Institut National Agronomique Paris-Grignon (INA P-G), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad), Centre d’Ecologie Fonctionnelle et Evolutive (CEFE), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Université Paul-Valéry - Montpellier 3 (UPVM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut de Recherche pour le Développement (IRD [France-Sud]), Unité de bioclimatologie, and Institut National de la Recherche Agronomique (INRA)

Subjects
P33 - Chimie et physique du sol, 010504 meteorology & atmospheric sciences, [SDE.MCG]Environmental Sciences/Global Changes, Management, Monitoring, Policy and Law, complex mixtures, 01 natural sciences, Soil respiration, 14. Life underwater, 0105 earth and related environmental sciences, Nature and Landscape Conservation, 2. Zero hunger, Ecology, Forestry, 04 agricultural and veterinary sciences, Soil carbon, 15. Life on land, Spatial heterogeneity, F61 - Physiologie végétale - Nutrition, Agronomy, Soil water, 040103 agronomy & agriculture, Litter, 0401 agriculture, forestry, and fisheries, Environmental science, Spatial variability, Ecosystem respiration, Respiration rate, TENEUR EN EAU DU SOL
Abstract

International audience; Our objectives were to quantify soil respiration in a 3-year-old Eucalyptus plantation in coastal Congo and to investigate both temporal and spatial variations of this major component of ecosystem respiration. Soil respiration exhibited pronounced seasonal variations that clearly reflected those of soil water content, with minimum values below 1.6 μmol m−2 s−1 at the end of the dry season in September and a maximum value of 5.6 μmol m−2 s−1 after re-wetting in December. An empirical model describing the relationship between soil respiration and soil water content predicts the seasonal variations in soil respiration reasonably well (R2 = 0.88), even if the effects of soil temperature and soil water content may be confounded since both factors co-vary across seasons. Spatial heterogeneity of soil respiration was clearly affected by management practices with higher respiration rate in slash inter-rows which received higher amounts of detritus at the logging stage, and lower respiration rate in haulage inter-rows used for heavy vehicle traffic. Higher values of soil respiration were also recorded in the vicinity of trunks than in the middle of the inter-rows. While soil water content is the main determinant of seasonal variation of soil respiration, it poorly accounts for its spatial variability over the experimental stand, except for days with low soil water content. Soil respiration was related neither to root biomass nor to soil carbon content, but was positively correlated with both leaf and total aboveground litter (i.e. leaf, bark and woody debris). Plots exhibiting the highest soil respiration also contained the highest amounts of aboveground litter. Microbial respiration associated with litter decomposition is likely a major component of soil respiration, and the spatial heterogeneity in litter fall probably accounts for most of its spatial variability in this Eucalyptus plantation.

Published
2004

45. Isoprenoid emissions ofQuercusspp. (Q. suberandQ. ilex) in mixed stands contrasting in interspecific genetic introgression

Author

Damien Landais, Serge Rambal, Aurélie Bonin, Celine Mir, Richard Joffre, Michael Staudt, Roselyne Lumaret, Centre d’Ecologie Fonctionnelle et Evolutive (CEFE), Université Paul-Valéry - Montpellier 3 (UPVM)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), and Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)

Subjects
0106 biological sciences, 010504 meteorology & atmospheric sciences, Physiology, Monoterpene, Introgression, Plant Science, Quercus suber, 01 natural sciences, genetic introgression, Gene flow, chemotypes, Botany, evergreen oaks, 0105 earth and related environmental sciences, Hybrid, VOC (volatile organic compound) emissions, Chemotype, biology, Ecology, monoterpenes, Interspecific competition, [SDV.BV.BOT]Life Sciences [q-bio]/Vegetal Biology/Botanics, 15. Life on land, biology.organism_classification, Fagaceae, chemotaxonomy, basal emission rate, isoprene, [SDV.EE.IEO]Life Sciences [q-bio]/Ecology, environment/Symbiosis, 010606 plant biology & botany
Abstract

International audience; • Among oak species, Quercus ilex is classified as a monoterpene emitter and Q. suber is mainly known as a nonisoprenoid emitter. The extent and origin of this diversification is unknown. • We examined intra-and interspecific emission variability in two mixed stands which differed in their level of hybridization and reciprocal genetic introgression based on variations in cytoplasmic (chloroplast DNA) and nuclear (allozyme) markers. • At both sites all trees identified as Q. ilex , or as recent descendants from Q. ilex × Q. suber hybrids, emitted monoterpenes. Of Q. suber trees (genetically introgressed or not by Q. ilex), 91% were also monoterpene emitters, and the remainder nonemitters. One tree identified as a Q. canariensis × Q. ilex hybrid emitted both isoprene and monoterpenes. Compared with Q. ilex , the standard emission rate of Q. suber was higher in summer and lower in autumn. Both species emitted the same monoterpenes, proportions of which showed significant intra-and interspecific variability. • The results suggest that Q. suber populations in the French Mediterranean intrinsically emit monoterpenes, and that gene flow between oak species contributes to diversification of emission signatures.

Published
2004

46. Some theoretical properties of the O-PLS method

Author

Thomas Verron, Robert Sabatier, and Richard Joffre

Subjects
business.industry, Calibration (statistics), Applied Mathematics, Computation, Structure (category theory), Filter (signal processing), Analytical Chemistry, Chemometrics, Constraint (information theory), Component (UML), Preprocessor, Artificial intelligence, business, Algorithm, Mathematics
Abstract

The objective of this paper is to present new properties of the orthogonal projections to latent structures (O-PLS) method developed by Trygg and Wold (J. Chemometrics 2002; 16: 119–128). The original orthogonal signal correction (OSC) filter of Wold et al. (Chemometrics Intell. Lab. Syst. 1998; 44: 175–185) removes systematic variation from X that is unrelated to Y. O-PLS is a more restrictive OSC filter. O-PLS removes only systematic variation in X explained in each PLS component that is not correlated with Y. O-PLS is a slight modification of the NIPALS PLS algorithm, which should make O-PLS a generally applicable preprocessing and filtering method. The computation of the O-PLS components under the constraint of being correlated with one PLS component imposes particular properties on the space spanned by the O-PLS components. This paper is divided into two main sections. First we give an application of O-PLS on near-infrared reflectance spectra of soil samples, showing some graphical properties. Then we give the mathematical justifications of these properties. Copyright © 2004 John Wiley & Sons, Ltd.

Published
2004

47. Drought controls over conductance and assimilation of a Mediterranean evergreen ecosystem: scaling from leaf to canopy

Author

Yann Nouvellon, Serge Rambal, Florent Mouillot, Alain Rocheteau, Markus Reichstein, Jean-Marc Ourcival, and Richard Joffre

Subjects
Canopy, Global and Planetary Change, Stomatal conductance, Ecology, Eddy covariance, Primary production, Atmospheric sciences, Canopy conductance, Field capacity, Water potential, Environmental Chemistry, Environmental science, Ecosystem respiration, General Environmental Science
Abstract

Drought control over conductance and assimilation was assessed using eddy flux and meteorological data monitored during four summer periods from 1998 to 2001 above a closed canopy of the Mediterranean evergreen oak tree Quercus ilex. Additional discrete measurements of soil water content and predawn leaf water potential were used to characterize the severity of the drought. Canopy conductance was estimated through the big-leaf approach of Penman‐ Monteith by inverting latent heat fluxes. The gross primary production (GPP) was estimated by adding ecosystem respiration to net ecosystem exchange. Ecosystem respiration was deduced from night flux when friction velocity (u * ) was greater than 0.35ms � 1 . Empirical equations were identified that related maximal canopy conductance and daily ecosystem GPP to relative soil water content (RWC), the ratio of current soil water content to the field capacity, and to the predawn leaf water potential. Both variables showed a strong decline with soil RWC for values lower than 0.7. The sharpest decline was observed for GPP. The curves reached zero for RWC 50.41 and 0.45 for conductance and GPP, respectively. When the predawn leaf water potential was used as a surrogate for soil water potential, both variables showed a hyperbolic decline with decreasing water potential. These results were compared with already published literature values obtained at leaf level from the same tree species. Scaling up from the leaf to ecosystem highlighted the limitation of two big-leaf representations: Penman‐Monteith and Sellers’ P factor. Neither held completely for comparing leaf and canopy fluxes. Tower measurements integrate fluxes from foliage elements clumped at several levels of organization: branch, tree, and ecosystem. The Q. ilex canopy exhibited non-random distribution of foliage, emphasizing the need to take into account a clumping index, the factor necessary to apply the Lambert‐Beer law to natural forests. Our results showed that drought is an important determinant in water losses and CO2 fluxes in water-limited ecosystems. In spite of the limitations inherent to the big-leaf representation of the canopy, the equations are useful for predicting the influence of environmental factors in Mediterranean woodlands and for interpreting ecosystem exchange measurements.

Published
2003

48. Quercus ilex Transpiration as Affected by a Prolonged Drought Period

Author

Francisco Domingo, J.M. Infante, R. Fernandez Ales, Serge Rambal, and Richard Joffre

Subjects
Agronomy, Evapotranspiration, Botany, Period (geology), Environmental science, Ecosystem, Plant Science, Horticulture, Evergreen, Water consumption, Tree transpiration, Transpiration
Abstract

The effect of an extended drought (from 1992 to 1995) on water relations was assessed on evergreen oak (Quercus ilex L.) in a dehesa ecosystem (Seville, Southern Spain). Diurnal and seasonal transpiration patterns were analysed at leaf (porometry) and whole-tree level (sap flow), focusing on the relationship between tree transpiration rates (Et) and potential evapotranspiration rates (PET). Daily maximum Et varied over the year, becoming higher between May and August, and lower between November and April. Annual Et (169 – 205 mm y−1) accounted for less than 40 % of annual rainfall. The prolonged drought did not affect the water relations of the Q. ilex, mainly due to strong stomatal regulation avoiding the loss of water. Stomatal control was found in all seasons, although it was stronger in summer. This behaviour leads to low water consumption and low Et/PET ratios throughout the year (0.05 to 0.27).

Published
2003

49. Actual litter decomposition rates in salt marshes measured using near-infrared reflectance spectroscopy

Author

Dominique Gillon, Virginie Bouchard, Jean-Claude Lefeuvre, and Richard Joffre

Subjects
geography, geography.geographical_feature_category, Aquatic ecosystem, chemistry.chemical_element, Soil science, Aquatic Science, Biology, Decomposition, Nitrogen, chemistry, Halophyte, Salt marsh, Botany, Litter, Terrestrial ecosystem, Microcosm, Ecology, Evolution, Behavior and Systematics
Abstract

Near-infrared reflectance spectroscopy (NIRS) has been widely applied as a holistic tool to investigate decomposition processes in terrestrial ecosystems. The objectives of this research were to determine the potential of NIRS to predict (1) the halophytic litter chemistry (i.e., carbon and nitrogen content) during decomposition, and (2) the stage of decomposition of halophytic litter. Decomposition experiments were conducted in the laboratory with microcosms placed under a wide range of physical characteristics and in the field with litterbags located along the elevation gradient (i.e., low to upper marsh). Microcosm experiments were used to calibrate the predictive equations. These calibration equations were then applied to the field data to test their capacity to predict %C, %N, and litter mass loss (LML). NIRS can be successfully applied to predict chemical composition of halophyte litter during decomposition processes. We hypothesized that the use of litterbags in the field might lead to a 20–40% overestimation of the decay rate as fine organic debris are lost through the meshes of the litterbags. NIRS can be used as a fast and nondestructive method to more accurately predict decay rates, and thus microbial consumption in aquatic environments.

Published
2003

50. Some determinants of the spatio-temporal fire cycle in a mediterranean landscape (Corsica, France)

Author

Serge Rambal, Florent Mouillot, José M. Moreno, Richard Joffre, and Jean-Pierre Ratte

Subjects
Mediterranean climate, geography, geography.geographical_feature_category, Ecology, Land use, Fire regime, Geography, Planning and Development, Land management, Vegetation, Shrubland, Environmental science, Physical geography, Landscape ecology, Fire ecology, Nature and Landscape Conservation
Abstract

Based on recent needs to accurately understand fire regimes and post-fire vegetation resilience at a supra-level for carbon cycle studies, this article focusses on the coupled history of fire and vegetation pattern for 40 years on a fire-prone area in central Corsica (France). This area has been submitted since the beginning of the 20th century to land abandonment and the remaining land management has been largely controlled by frequent fires. Our objectives were to rebuild vegetation and fire maps in order to determine the factors which have driven the spatial and temporal distribution of fires on the area, what were the feed backs on the vegetation dynamics, and the long-term consequences of this inter-relationship. The results show a stable but high frequency of small fires, coupled with forest expansion over the study period. The results particularly illustrate the spatial distribution of fires according to topography and vegetation, leading to a strong contrast between areas never burnt and areas which have been burnt up to 7 times. Fires, when occuring, affect on average 9 to 12% of the S, SE and SW facing slopes (compared to only 2 to 5% for the N facing slopes), spread recurrently over ridge tops, affect all the vegetation types but reburn preferentially shrublands and grasslands. As these fire-proning parameters have also been shown to decrease the regeneration capacity of forests, this study highlights the needs in spatial studies (both in terms of fire spread and vegetation dynamic) to accurately apprehend vegetation dynamic and functionning in fire-prone areas.

Published
2003

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