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3. Incorporating photosynthetic acclimation improves stomatal optimisation models.

Author

Flo, Victor, Joshi, Jaideep, Sabot, Manon, Sandoval, David, and Prentice, Iain Colin

Subjects
STOMATA, CLIMATE change, PLANT species, PHOTOSYNTHESIS, DROUGHTS, ACCLIMATIZATION
Abstract

Stomatal opening in plant leaves is regulated through a balance of carbon and water exchange under different environmental conditions. Accurate estimation of stomatal regulation is crucial for understanding how plants respond to changing environmental conditions, particularly under climate change. A new generation of optimality‐based modelling schemes determines instantaneous stomatal responses from a balance of trade‐offs between carbon gains and hydraulic costs, but most such schemes do not account for biochemical acclimation in response to drought. Here, we compare the performance of six instantaneous stomatal optimisation models with and without accounting for photosynthetic acclimation. Using experimental data from 37 plant species, we found that accounting for photosynthetic acclimation improves the prediction of carbon assimilation in a majority of the tested models. Photosynthetic acclimation contributed significantly to the reduction of photosynthesis under drought conditions in all tested models. Drought effects on photosynthesis could not accurately be explained by the hydraulic impairment functions embedded in the stomatal models alone, indicating that photosynthetic acclimation must be considered to improve estimates of carbon assimilation during drought. Summary statement: Accounting for photosynthetic acclimation improves the predictions of carbon assimilation in all the stomatal optimisation models evaluated. The influence of drought on photosynthesis cannot be fully explained by the hydraulic impairment function of the stomatal models alone. [ABSTRACT FROM AUTHOR]

Published
2024
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6. Optimising height‐growth predicts trait responses to water availability and other environmental drivers.

Author

Towers, Isaac R., O'Reilly‐Nugent, Andrew, Sabot, Manon E. B., Vesk, Peter A., and Falster, Daniel S.

Abstract

Future changes in climate, together with rising atmospheric CO2 CO2, may reorganise the functional composition of ecosystems. Without long‐term historical data, predicting how traits will respond to environmental conditions—in particular, water availability—remains a challenge. While eco‐evolutionary optimality theory (EEO) can provide insight into how plants adapt to their environment, EEO approaches to date have been formulated on the assumption that plants maximise carbon gain, which omits the important role of tissue construction and size in determining growth rates and fitness. Here, we show how an expanded optimisation framework, focussed on individual growth rate, enables us to explain shifts in four key traits: leaf mass per area, sapwood area to leaf area ratio (Huber value), wood density and sapwood‐specific conductivity in response to soil moisture, atmospheric aridity, CO2 CO2 and light availability. In particular, we predict that as conditions become increasingly dry, height‐growth optimising traits shift from resource‐acquisitive strategies to resource‐conservative strategies, consistent with empirical responses across current environmental gradients of rainfall. These findings can explain both the shift in traits and turnover of species along existing environmental gradients and changing future conditions and highlight the importance of both carbon assimilation and tissue construction in shaping the functional composition of vegetation across climates. Summary Statement: Eco‐evolutionary theory (EEO) can yield insight into how plant traits are likely to adapt to future climatic conditions. However, current implementations typically focus on maximising plant carbon gain while omitting important processes related to tissue construction and relative allocation which are important for understanding plant growth rates, and consequently, fitness. Using a height‐growth based trait optimisation framework incorporating plant hydraulics, we predict how four key traits: leaf mass per area, sapwood area to leaf area ratio (Huber value), wood density and sapwood‐specific conductivity, respond to soil moisture, atmospheric aridity, CO2 CO2 and light availability and consider these predictions in light of empirical observations. Finally, we use this framework to explore how simultaneous optimisation of multiple traits can yield species turnover across a soil moisture gradient. The model shows that, when plants maximise height‐growth rate, the optimal value of leaf‐mass‐per‐area, Huber value, wood density and sapwood‐specific conductivity shifts with the environment and through plant ontogeny in line with empirical results. [ABSTRACT FROM AUTHOR]

Published
2024
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7. Leaf morphological traits show greater responses to changes in climate than leaf physiological traits and gas exchange variables.

Author

Everingham, Susan E., Offord, Catherine A., Sabot, Manon E. B., and Moles, Angela T.

Subjects
CLIMATE change, EFFECT of human beings on climate change, LEAF morphology, WATER efficiency, LEAF anatomy, CLIMATE extremes
Abstract

Adaptation to changing conditions is one of the strategies plants may use to survive in the face of climate change. We aimed to determine whether plants' leaf morphological and physiological traits/gas exchange variables have changed in response to recent, anthropogenic climate change. We grew seedlings from resurrected historic seeds from ex‐situ seed banks and paired modern seeds in a common‐garden experiment. Species pairs were collected from regions that had undergone differing levels of climate change using an emerging framework—Climate Contrast Resurrection Ecology, allowing us to hypothesise that regions with greater changes in climate (including temperature, precipitation, climate variability and climatic extremes) would be greater trait responses in leaf morphology and physiology over time. Our study found that in regions where there were greater changes in climate, there were greater changes in average leaf area, leaf margin complexity, leaf thickness and leaf intrinsic water use efficiency. Changes in leaf roundness, photosynthetic rate, stomatal density and the leaf economic strategy of our species were not correlated with changes in climate. Our results show that leaves do have the ability to respond to changes in climate, however, there are greater inherited responses in morphological leaf traits than in physiological traits/variables and greater responses to extreme measures of climate than gradual changes in climatic means. It is vital for accurate predictions of species' responses to impending climate change to ensure that future climate change ecology studies utilise knowledge about the difference in both leaf trait and gas exchange responses and the climate variables that they respond to. [ABSTRACT FROM AUTHOR]

Published
2024
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10. When do plant hydraulics matter in terrestrial biosphere modelling?

Author

Paschalis, Athanasios, De Kauwe, Martin G., Sabot, Manon, and Fatichi, Simone

Subjects
HYDRAULICS, TROPICAL ecosystems, BIOSPHERE, PLANT phenology, PLANT-water relationships, WATER storage, DROUGHTS
Abstract

The ascent of water from the soil to the leaves of vascular plants, described by the study of plant hydraulics, regulates ecosystem responses to environmental forcing and recovery from stress periods. Several approaches to model plant hydraulics have been proposed. In this study, we introduce four different versions of plant hydraulics representations in the terrestrial biosphere model T&C to understand the significance of plant hydraulics to ecosystem functioning. We tested representations of plant hydraulics, investigating plant water capacitance, and long‐term xylem damages following drought. The four models we tested were a combination of representations including or neglecting capacitance and including or neglecting xylem damage legacies. Using the models at six case studies spanning semiarid to tropical ecosystems, we quantify how plant xylem flow, plant water storage and long‐term xylem damage can modulate overall water and carbon dynamics across multiple time scales. We show that as drought develops, models with plant hydraulics predict a slower onset of plant water stress, and a diurnal variability of water and carbon fluxes closer to observations. Plant water storage was found to be particularly important for the diurnal dynamics of water and carbon fluxes, with models that include plant water capacitance yielding better results. Models including permanent damage to conducting plant tissues show an additional significant drought legacy effect, limiting plant productivity during the recovery phase following major droughts. However, when considering ecosystem responses to the observed climate variability, plant hydraulic modules alone cannot significantly improve the overall model performance, even though they reproduce more realistic water and carbon dynamics. This opens new avenues for model development, explicitly linking plant hydraulics with additional ecosystem processes, such as plant phenology and improved carbon allocation algorithms. [ABSTRACT FROM AUTHOR]

Published
2024
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11. Limited range shifting in biocrusts despite climate warming: A 25‐year resurvey.

Author

Mallen‐Cooper, Max, Cornwell, William K., Slavich, Eve, Sabot, Manon E. B., Xirocostas, Zoe A., and Eldridge, David J.

Subjects
GLOBAL warming, CRUST vegetation, CLIMATE change models, ARID regions
Abstract

The ranges of many species globally have already shifted to maintain climatic equilibrium in the face of climate change.Biocrusts—soil surface dwelling communities of lichens, bryophytes and microbes—play important functional roles in many ecosystems, particularly in drylands. Compared to better studied animal and plant taxa, dryland biocrusts have different establishment requirements and have never been assessed for historical range shifts.Here, we revisited the sites (N = 204) of a 25‐year‐old biocrust survey across a large area (400,000 km2) of drylands in south‐eastern Australia. We used quadratic models to quantify changes in the climate niches of 15 lichen, eight moss and five liverwort taxa, as well as biocrust cover and richness.Our models showed that the observed climatic niches of most taxa have become hotter and drier in the past quarter century, yet the responses of the vast majority of taxa are consistent with remaining in the same geographic space. A similar pattern was observed at the community level, where the peak of biocrust cover and richness now occurs in a hotter, drier environment. Notable exceptions were the liverwort Riccia lamellosa and lichens in the genera Cladonia and Xanthoparmelia, which showed signs of contraction at their arid range edges.Unlike more mobile taxa, most biocrust species have yet to shift geographically and may already be lagging behind the pace of climate change. One explanation for the mortality lag is that long‐term climate variability in the system is extensive, which may have selected for the ability to withstand multi‐year warm periods as long as there is an eventual return to milder conditions. However, no forecasts of future climate include a return to milder conditions, suggesting there will be an eventual loss of ecosystem multifunctionality at the contracting front. Expansion lags are most likely due to delays in the mortality of competing vascular plants.Synthesis: Our study provides a valuable contribution to the knowledge of range shifts in understudied taxa and highlights a future need to promote the expansion of biocrusts to maintain the provision of ecosystem functions and services across their range. [ABSTRACT FROM AUTHOR]

Published
2023
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15. Predicting resilience through the lens of competing adjustments to vegetation function

Author

Sabot, Manon E. B., primary, De Kauwe, Martin G., additional, Pitman, Andy J., additional, Ellsworth, David S., additional, Medlyn, Belinda E., additional, Caldararu, Silvia, additional, Zaehle, Sönke, additional, Crous, Kristine Y., additional, Gimeno, Teresa E., additional, Wujeska‐Klause, Agnieszka, additional, Mu, Mengyuan, additional, and Yang, Jinyan, additional

Published
2022
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17. One Stomatal Model to Rule Them All? Toward Improved Representation of Carbon and Water Exchange in Global Models

Author

Sabot, Manon E. B., primary, De Kauwe, Martin G., additional, Pitman, Andy J., additional, Medlyn, Belinda E., additional, Ellsworth, David S., additional, Martin‐StPaul, Nicolas K., additional, Wu, Jin, additional, Choat, Brendan, additional, Limousin, Jean‐Marc, additional, Mitchell, Patrick J., additional, Rogers, Alistair, additional, and Serbin, Shawn P., additional

Published
2022
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20. Trading water for carbon in a changing climate: can optimality theory improve the predictability of land surface models?

Author

Sabot, Manon

Abstract

Terrestrial ecosystems are facing unprecedented threats from climate change. Projected increases in the intensity, frequency, and duration droughts and heatwaves could drive future mass forest die-back. However, assessing future risk remains a challenge because climate models demonstrate systematic errors in predicting plant function when resources become limiting (e.g., water). To improve predictions of ecosystem resilience, major model weaknesses in the formulation of plant responses to climatic stress must be resolved. The aim of this thesis is to examine whether optimality principles can improve land surface model (LSM) predictability, through improved process-representation of vegetation function, and by reducing existing reliance on poorly supported empirical functions. Major contributions from the thesis include: 1. The development and testing of a novel canopy gas-exchange scheme, that optimises stomatal conductance with respect to photosynthetic and hydraulic functions, for use in LSMs. The new scheme improves the simulation of forest evaporative fluxes over a mesic to xeric ecosystem gradient in Europe, reducing errors by over 60% compared to a reference empirical scheme. 2. A multi-model comparison study of potential alternative stomatal coupling schemes, including empirical (n=3) and optimal (n=9) formulations, carried out in a single LSM framework. The findings provide important insight into: (i) model identifiability and parameter redundancy; (ii) how and why models diverge from each other and observations; and (iii) provide guidance for future model development. 3. The combination and evaluation of competing optimisation approaches, with contrasting fitness targets, in a LSM framework – competing approaches have been proposed and evaluated in isolation, but seldom implemented together in LSMs. Here, the canopy gas-exchange scheme tested in 1) is coupled to a scheme that optimises leaf nitrogen investment, and both approaches are extended to account for system legacies from drought, before being evaluated for their ability to coherently interact with one another. This thesis demonstrates the wide-ranging scope for optimality theory to be incorporated into LSMs. Plant optimality theory is grounded in physiological principles, and it adjusts to changing environmental constraints, providing a pathway to improve both the theoretical underpinning and the predictability of LSMs.

Published
2022
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22. Southern hemisphere plants show more delays than advances in flowering phenology.

Author

Everingham, Susan E., Blick, Raymond A. J., Sabot, Manon E. B., Slavich, Eve, and Moles, Angela T.

Subjects
FLOWERING of plants, PLANT phenology, PHENOLOGY, FLOWERING time, BOTANICAL specimens, CLIMATE change
Abstract

Shifts in flowering phenology have been studied in detail in the northern hemisphere and are a key plant response to climate change. However, there are relatively fewer data on species' phenological shifts in the southern hemisphere.We combined historic field data, data from herbarium specimens dating back to 1842 and modern field data for 37 Australian species to determine whether species were flowering earlier in the year than they had in the past. We also combined our results with data compiled in the southern and northern hemispheres, respectively, to determine whether southern hemisphere species are showing fewer advances in flowering phenology through time.Across our study species, we found that 12 species had undergone significant shifts in flowering time, with four species advancing their flowering and eight species delaying their flowering. The remaining 25 species showed no significant shifts in their flowering phenology. These findings are important because delays or lack of shifts in flowering phenology can lead to mismatches in trophic interactions between plants and pollinators or seed dispersers, which can have substantial impacts on ecosystem functioning and primary productivity. Combining our field results with data compiled from the literature showed that only 58.5% of southern hemisphere species were advancing their flowering time, compared with 81.6% of species that were advancing their flowering time in the northern hemisphere. Our study provides further evidence that it is not adequate for ecologists to assume that southern hemisphere ecosystems will respond to future climate change in the same way as ecosystems north of the Equator.Synthesis. Field data and data from the literature indicate that southern hemisphere species are showing fewer advances in their flowering phenology through time, especially in comparison to northern hemisphere species. [ABSTRACT FROM AUTHOR]

Published
2023
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23. Integrating the evidence for a terrestrial carbon sink caused by increasing atmospheric CO2

Author

Walker, Anthony P., De Kauwe, Martin G., Bastos, Ana, Belmecheri, Soumaya, Georgiou, Katerina, Keeling, Ralph F., McMahon, Sean M., Medlyn, Belinda E., Moore, David J. P., Norby, Richard J., Zaehle, Söenke, Anderson-Teixeira, Kristina J., Battipaglia, Giovanna, Brienen, Roel J. W., Cabugao, Kristine G., Cailleret, Maxime, Campbell, Elliott, Canadell, Josep G., Ciais, Philippe, Craig, Matthew E., Ellsworth, David S., Farquhar, Graham D., Fatichi, Simone, Fisher, Joshua B., Frank, David C., Graven, Heather, Gu, Lianhong, Haverd, Vanessa, Heilman, Kelly, Heimann, Martin, Hungate, Bruce A., Iversen, Colleen M., Joos, Fortunat, Jiang, Mingkai, Keenan, Trevor F., Knauer, Jürgen, Körner, Christian, Leshyk, Victor O., Leuzinger, Sebastian, Liu, Yao, MacBean, Natasha, Malhi, Yadvinder, McVicar, Tim R., Penuelas, Josep, Pongratz, Julia, Powell, A. Shafer, Riutta, Terhi, Sabot, Manon E. B., Schleucher, Jürgen, Sitch, Stephen, Smith, William K., Sulman, Benjamin, Taylor, Benton, Terrer, César, Torn, Margaret S., Treseder, Kathleen K., Trugman, Anna T., Trumbore, Susan E., van Mantgem, Phillip J., Voelker, Steve L., Whelan, Mary E., Zuidema, Pieter A., Walker, Anthony P., De Kauwe, Martin G., Bastos, Ana, Belmecheri, Soumaya, Georgiou, Katerina, Keeling, Ralph F., McMahon, Sean M., Medlyn, Belinda E., Moore, David J. P., Norby, Richard J., Zaehle, Söenke, Anderson-Teixeira, Kristina J., Battipaglia, Giovanna, Brienen, Roel J. W., Cabugao, Kristine G., Cailleret, Maxime, Campbell, Elliott, Canadell, Josep G., Ciais, Philippe, Craig, Matthew E., Ellsworth, David S., Farquhar, Graham D., Fatichi, Simone, Fisher, Joshua B., Frank, David C., Graven, Heather, Gu, Lianhong, Haverd, Vanessa, Heilman, Kelly, Heimann, Martin, Hungate, Bruce A., Iversen, Colleen M., Joos, Fortunat, Jiang, Mingkai, Keenan, Trevor F., Knauer, Jürgen, Körner, Christian, Leshyk, Victor O., Leuzinger, Sebastian, Liu, Yao, MacBean, Natasha, Malhi, Yadvinder, McVicar, Tim R., Penuelas, Josep, Pongratz, Julia, Powell, A. Shafer, Riutta, Terhi, Sabot, Manon E. B., Schleucher, Jürgen, Sitch, Stephen, Smith, William K., Sulman, Benjamin, Taylor, Benton, Terrer, César, Torn, Margaret S., Treseder, Kathleen K., Trugman, Anna T., Trumbore, Susan E., van Mantgem, Phillip J., Voelker, Steve L., Whelan, Mary E., and Zuidema, Pieter A.

Abstract

Atmospheric carbon dioxide concentration ([CO2]) is increasing, which increases leaf‐scale photosynthesis and intrinsic water‐use efficiency. These direct responses have the potential to increase plant growth, vegetation biomass, and soil organic matter; transferring carbon from the atmosphere into terrestrial ecosystems (a carbon sink). A substantial global terrestrial carbon sink would slow the rate of [CO2] increase and thus climate change. However, ecosystem CO2 responses are complex or confounded by concurrent changes in multiple agents of global change and evidence for a [CO2]‐driven terrestrial carbon sink can appear contradictory. Here we synthesize theory and broad, multidisciplinary evidence for the effects of increasing [CO2] (iCO2) on the global terrestrial carbon sink. Evidence suggests a substantial increase in global photosynthesis since pre‐industrial times. Established theory, supported by experiments, indicates that iCO2 is likely responsible for about half of the increase. Global carbon budgeting, atmospheric data, and forest inventories indicate a historical carbon sink, and these apparent iCO2 responses are high in comparison to experiments and predictions from theory. Plant mortality and soil carbon iCO2 responses are highly uncertain. In conclusion, a range of evidence supports a positive terrestrial carbon sink in response to iCO2, albeit with uncertain magnitude and strong suggestion of a role for additional agents of global change.

Published
2021
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26. Integrating the evidence for a terrestrial carbon sink caused by increasing atmospheric CO2

Author

Walker, Anthony P., primary, De Kauwe, Martin G., additional, Bastos, Ana, additional, Belmecheri, Soumaya, additional, Georgiou, Katerina, additional, Keeling, Ralph F., additional, McMahon, Sean M., additional, Medlyn, Belinda E., additional, Moore, David J. P., additional, Norby, Richard J., additional, Zaehle, Sönke, additional, Anderson‐Teixeira, Kristina J., additional, Battipaglia, Giovanna, additional, Brienen, Roel J. W., additional, Cabugao, Kristine G., additional, Cailleret, Maxime, additional, Campbell, Elliott, additional, Canadell, Josep G., additional, Ciais, Philippe, additional, Craig, Matthew E., additional, Ellsworth, David S., additional, Farquhar, Graham D., additional, Fatichi, Simone, additional, Fisher, Joshua B., additional, Frank, David C., additional, Graven, Heather, additional, Gu, Lianhong, additional, Haverd, Vanessa, additional, Heilman, Kelly, additional, Heimann, Martin, additional, Hungate, Bruce A., additional, Iversen, Colleen M., additional, Joos, Fortunat, additional, Jiang, Mingkai, additional, Keenan, Trevor F., additional, Knauer, Jürgen, additional, Körner, Christian, additional, Leshyk, Victor O., additional, Leuzinger, Sebastian, additional, Liu, Yao, additional, MacBean, Natasha, additional, Malhi, Yadvinder, additional, McVicar, Tim R., additional, Penuelas, Josep, additional, Pongratz, Julia, additional, Powell, A. Shafer, additional, Riutta, Terhi, additional, Sabot, Manon E. B., additional, Schleucher, Juergen, additional, Sitch, Stephen, additional, Smith, William K., additional, Sulman, Benjamin, additional, Taylor, Benton, additional, Terrer, César, additional, Torn, Margaret S., additional, Treseder, Kathleen K., additional, Trugman, Anna T., additional, Trumbore, Susan E., additional, van Mantgem, Phillip J., additional, Voelker, Steve L., additional, Whelan, Mary E., additional, and Zuidema, Pieter A., additional

Published
2020
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27. Identifying areas at risk of drought‐induced tree mortality across South‐Eastern Australia

Author

De Kauwe, Martin G., primary, Medlyn, Belinda E., additional, Ukkola, Anna M., additional, Mu, Mengyuan, additional, Sabot, Manon E. B., additional, Pitman, Andrew J., additional, Meir, Patrick, additional, Cernusak, Lucas A., additional, Rifai, Sami W., additional, Choat, Brendan, additional, Tissue, David T., additional, Blackman, Chris J., additional, Li, Ximeng, additional, Roderick, Michael, additional, and Briggs, Peter R., additional

Published
2020
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30. Hydrologie et production agricole dans le nord-ouest de l'Amazonie

Author

Ronchail, Josyane, Schor, Tatiana, Espinoza, Jhan Carlo, Sabot, Manon, Pinheiro, Heitor, Gomez Davila, Percy, Drapeau, Guillaume, Michot, Véronique, Filizola, Naziano, Guyot, Jean-Loup, Sultan, Benjamin, Martinez, Jean-Michel, Processus de la variabilité climatique tropicale et impacts (PARVATI), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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 Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université Paris Diderot - Paris 7 (UPD7), Federal University of Amazonas, Instituto Geofísico del Perú (IGP), Université Pierre et Marie Curie - Paris 6 (UPMC), University of the Amazonas State, Ministerio de la Agricultura (MINAG - Ministerio de la Agricultura ), Pôle de recherche pour l'organisation et la diffusion de l'information géographique (PRODIG), Université Paris 1 Panthéon-Sorbonne (UP1)-Institut de Recherche pour le Développement (IRD)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris-Sorbonne (UP4)-AgroParisTech-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Littoral, Environnement, Télédétection, Géomatique (LETG - Rennes), Littoral, Environnement, Télédétection, Géomatique UMR 6554 (LETG), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Université d'Angers (UA)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Brest (UBO)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut de Géographie et d'Aménagement Régional de l'Université de Nantes (IGARUN), Université de Nantes (UN)-Université de Nantes (UN)-Université de Caen Normandie (UNICAEN), Université de Nantes (UN)-Université de Nantes (UN), Institut de Recherche pour le Développement (IRD [Bolivie]), Institut de Recherche pour le Développement, Géosciences Environnement Toulouse (GET), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-AgroParisTech-Université Paris-Sorbonne (UP4)-École pratique des hautes études (EPHE)-Institut de Recherche pour le Développement (IRD)-Université Panthéon-Sorbonne (UP1), Normandie Université (NU)-Normandie Université (NU)-Université d'Angers (UA)-Université de Nantes (UN)-École pratique des hautes études (EPHE)-Université de Brest (UBO)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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 Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris 1 Panthéon-Sorbonne (UP1)-Institut de Recherche pour le Développement (IRD)-École pratique des hautes études (EPHE), Normandie Université (NU)-Normandie Université (NU)-Université d'Angers (UA)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Brest (UBO)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Géographie et d'Aménagement Régional de l'Université de Nantes (IGARUN), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Rainfall, 010504 meteorology & atmospheric sciences, DECRUE, Geography, Planning and Development, 01 natural sciences, PLAINE INONDABLE, Perú, Peru, arroz, ComputingMilieux_MISCELLANEOUS, riz, Recession period, 2. Zero hunger, purl.org/pe-repo/ocde/ford#1.05.09 [http], Amazon rainforest, 05 social sciences, pluie, VARIATION ANNUELLE, Geography, CRUE, ETIAGE, Amazon basin, 050703 geography, Hydrological cycle, REGIME HYDROLOGIQUE, 0507 social and economic geography, lluvia, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], cycle hydrologique, purl.org/pe-repo/ocde/ford#1.05.00 [http], ciclo hidrológico, Amazonia, CULTURE DE DECRUE, Amazonía, Amazonie, Flood recession, 0105 earth and related environmental sciences, Earth-Surface Processes, chuva, periodo de recesión, Forestry, 15. Life on land, purl.org/pe-repo/ocde/ford#1.05.11 [http], COURS D'EAU, décrue, 13. Climate action, Pérou, Rice, descidas, Hydrology, STATION HYDROLOGIQUE
Abstract

En « Amazonie des rivières », la période de basses eaux permet la mise en culture de vastes zones exondées et fertiles sur les berges des rivières et dans les plaines d’inondation. La variabilité des extrêmes hydrologiques et celle de la structure du cycle de décrue, facteurs réputés importants pour la qualité des récoltes sont explorés à la station fluviométrique de Tamshiyacu sur le fleuve Amazonas. Le riz, culture rentable dans cette région, est notre référence. Les résultats ne présentent pas les liens supposés entre résultats agricoles et durée de la saison de basses eaux ou vitesse de remontée des eaux. Néanmoins, ils montrent la baisse des étiages, l’allongement de la durée de décrue en relation avec un retard de la montée des eaux et une accélération de la remontée des eaux pendant la période 1985-2015. In the northwestern Amazon basin, the low water period favors flood recession farming on large emerging fertile surfaces on the river banks and in the inundations plains. The variability of hydrological extremes and of the structure of the flood recession cycle are analyzed in the fluviometric Tamshiyacu station on the Amazonas River, as they are considered as important for the crop quality. Rice cropping which is a profitable activity in this region is neither related to the duration of low-waters, nor to the speed of the rising water. But this work show that since 1985, low water levels have decreased while the duration of the low water period has increased. Moreover, there has been an acceleration of the speed of the water rising. En el noroeste de la cuenca amazónica, el periodo de estiaje de los ríos favorece el cultivo en vastas zonas fértiles que emergentes en los bancos de arena y las planicies de inundación. La variabilidad de los extremos hidrológicos y de la estructura del ciclo de recesión de las aguas son factores importantes para la calidad y cantidad de la cosecha. Estos factores hidrológicos son analizados en la estación hidrométrica de Tamshiyacu en el Río Amazonas (Perú). Como referencia se emplea el cultivo de arroz, que es rentable en esta región. Los resultados presentados no muestran relación entre la producción agrícola y la duración del periodo de aguas bajas o la velocidad de incremento de las aguas. No obstante, este estudio muestra que durante el periodo 1985-2015 el nivel de las aguas bajas ha disminuido, mientras que la duración del periodo de estiaje se ha incrementado. Además se documenta una aceleración en la velocidad en el incremento de las aguas entre el periodo de aguas bajas y aguas altas. Na « Amazônia dos grandes rios » o período de aguas baixas permite cultivos em vastas zonas férteis de várzeas ao longo dos rios e planicies de inundação. A variabilidade dos extremos hidrológicos e a da estrutura dos ciclos de descidas são fatores importantes para a qualidade e quantidade de colheita. Exploramos esta relação na estação hidrológica de Tamshiyacu no rio Amazonas, Peru. O arroz, cultura rentável nesta região, é referência. Os resultados apresentados mostram pouca relação entre a duração das águas baixas ou a velocidade da subida. Mas este estudo mostra que desde 1985-2015 o nível das águas baixas tem diminuido enquanto que a duração do mesmo período tem aumentado. Além do que tem havido uma aceleração da velocidade de subida das aguas.

Published
2016

31. Variabilité du climat, de l'hydrologie et agriculture dans le nord-ouest de l'Amazonie

Author

ronchail, josyane, Schor, Tatiana, Filizola, Naziano, Sabot, Manon, Pinto, Moises, Pinheiro, Heitor, Gomez Davila, Percy, Drapeau, Guillaume, Espinoza Villar, Jhan Carlo, Martinez, Jean-Michel, Turc, Patricia, Cochonneau, Gérard, Santini, William, Université Paris Diderot - Paris 7 (UPD7), Processus de la variabilité climatique tropicale et impacts (PARVATI), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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 Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), University of the Amazonas State, Université Pierre et Marie Curie - Paris 6 (UPMC), Ministerio de la Agricultura (MINAG), Institut Pierre-Simon-Laplace (IPSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National d'Études Spatiales [Toulouse] (CNES)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Pôle de recherche pour l'organisation et la diffusion de l'information géographique (PRODIG), Université Paris 1 Panthéon-Sorbonne (UP1)-Institut de Recherche pour le Développement (IRD)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris-Sorbonne (UP4)-AgroParisTech-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Universidad Nacional Agraria La Molina (UNALM), Instituto Geofisico del Peru, Instituto Geofísico del Perú, Géosciences Environnement Toulouse (GET), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Institut de Recherche et de Développement Brasilia (IRD Brasilia), Institut de Recherche et de Développement, Association des géographes français, Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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 Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Université Paris 1 Panthéon-Sorbonne (UP1)-Institut de Recherche pour le Développement (IRD)-École Pratique des Hautes Études (EPHE), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
extrêmes hydrologique, pêche, [SHS.GEO]Humanities and Social Sciences/Geography, chasse, cycle hydrologique, riz, agriculture, Amazonie
Abstract

National audience; Dans la région nord-ouest du bassin amazonien, on observe des variabilités saisonnière etinterannuelle très importantes des hauteurs d’eau des rivières. Un marnage d’en moyenne 9mètres autorise des cultures de décrue sur les berges et dans les plaines d’inondation, une pêcheplus aisée dans les points d’eau restants. Mais la chasse est rendue plus difficile car elle s’opèresur de vastes territoires. En conséquence, on observe une variation saisonnière de ladisponibilité et du coût de la nourriture. Produits agricoles et poissons sont plus abondants etmoins chers pendant la saison d’étiage tandis que les produits de la chasse deviennent plusrares. Nous montrerons que les années de très fortes crues ou sécheresses, devenues trèsfréquentes depuis les années 1990, modifient elles-aussi les niveaux de production et les prixdes aliments. Ces travaux sont réalisés à partir d’enquêtes sur le terrain et des donnéesstatistiques d’organismes publics.

Published
2015

32. Hydrological extremes and food security in western Amazon

Author

ronchail, josyane, Schor, Tatiana, Moraes, Andre, Pinto, Moises, Sabot , Manon, Pinheiro, Heitor, Espinoza Villar, Jhan Carlo, Drapeau, Guillaume, Quirion, Philippe, Guyot, Jean-Loup, Filizola, Naziano, Sultan, Benjamin, Martinez, Jean-Michel, Processus de la variabilité climatique tropicale et impacts (PARVATI), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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 Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université Paris Diderot - Paris 7 (UPD7), University of the Amazonas State, Université Pierre et Marie Curie - Paris 6 (UPMC), Universidad Nacional Agraria La Molina (UNALM), Institut Pierre-Simon-Laplace (IPSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), centre international de recherche sur l'environnement et le développement (CIRED), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-École des hautes études en sciences sociales (EHESS)-AgroParisTech-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS), Géosciences Environnement Toulouse (GET), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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 Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Centre National de la Recherche Scientifique (CNRS)-École des Ponts ParisTech (ENPC)-École des hautes études en sciences sociales (EHESS)-AgroParisTech-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), and Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)

Subjects
[SDE.MCG]Environmental Sciences/Global Changes, hydrology, Amazon basin, food security, [SHS.GEO]Humanities and Social Sciences/Geography, hydrological cycle, hydrological extremes, [SDE.ES]Environmental Sciences/Environmental and Society, agriculture
Abstract

International audience; The water level of the Amazon and of its tributaries varies significantly from one season to another. For instance, at Iquitos station (Peru), the water level varies from 18 meters in May-June to 8 meters in September-October. That is why, during the low-flow period, cultivating becomes possible and is important on the riverbanks and in the inundation plains. Agricultural production in a family-based system on the riverbanks and inundation plains is very important in terms of guarantee of supply for food security. In order to understand the important relation between agriculture, food security and hydrological system some characteristics of the local agriculture in the Amazonian region located between Iquitos (Peru) and the triple frontier between Brazil, Peru and Colombia are first presented using results from field observations, survey and data from the Peruvian and Brazilian Agricultural agencies. Then, information about the interannual variability (1980-2014) of the hydrological cycle of the Solimões River are presented: discussion and definition of the dates of the beginning and of the end of the low-flow period, duration of the low flow period, velocity of the water level changes during the increasing and decreasing flow periods, presence of “false alarm” at the beginning or at the end of the dry and the wet period, … This part is developed using water level data from the national hydrological services of Peru and Brazil and from the Environmental Research Observatory SOHYBAM (Geodynamical, hydrological and biogeochemical control of erosion/alteration and material transport in the Amazon basin). Finally, as a shorter than usual length of the low flow season, a rapid increase of the water level, a “false” beginning of the low water season, etc. are hazards that may put at risk sowing and plant development, hydrological parameters are related to yield values seeking possible correlations between extreme events and food security in the region.

Published
2015

33. Trading water for carbon in a changing climate: can optimality theory improve the predictability of land surface models?

Author

Sabot, Manon ; https://orcid.org/0000-0002-9440-4553

Abstract

Terrestrial ecosystems are facing unprecedented threats from climate change. Projected increases in the intensity, frequency, and duration droughts and heatwaves could drive future mass forest die-back. However, assessing future risk remains a challenge because climate models demonstrate systematic errors in predicting plant function when resources become limiting (e.g., water). To improve predictions of ecosystem resilience, major model weaknesses in the formulation of plant responses to climatic stress must be resolved. The aim of this thesis is to examine whether optimality principles can improve land surface model (LSM) predictability, through improved process-representation of vegetation function, and by reducing existing reliance on poorly supported empirical functions. Major contributions from the thesis include: 1. The development and testing of a novel canopy gas-exchange scheme, that optimises stomatal conductance with respect to photosynthetic and hydraulic functions, for use in LSMs. The new scheme improves the simulation of forest evaporative fluxes over a mesic to xeric ecosystem gradient in Europe, reducing errors by over 60% compared to a reference empirical scheme. 2. A multi-model comparison study of potential alternative stomatal coupling schemes, including empirical (n=3) and optimal (n=9) formulations, carried out in a single LSM framework. The findings provide important insight into: (i) model identifiability and parameter redundancy; (ii) how and why models diverge from each other and observations; and (iii) provide guidance for future model development. 3. The combination and evaluation of competing optimisation approaches, with contrasting fitness targets, in a LSM framework – competing approaches have been proposed and evaluated in isolation, but seldom implemented together in LSMs. Here, the canopy gas-exchange scheme tested in 1) is coupled to a scheme that optimises leaf nitrogen investment, and both approaches are extended to account for system legacies from drought, before being evaluated for their ability to coherently interact with one another. This thesis demonstrates the wide-ranging scope for optimality theory to be incorporated into LSMs. Plant optimality theory is grounded in physiological principles, and it adjusts to changing environmental constraints, providing a pathway to improve both the theoretical underpinning and the predictability of LSMs.

Published
2022

34. Integrating the evidence for a terrestrial carbon sink caused by increasing atmospheric CO2

Author

Walker, Anthony P., De Kauwe, Martin G., Bastos, Ana, Belmecheri, Soumaya, Georgiou, Katerina, Keeling, Ralph F., McMahon, Sean M., Medlyn, Belinda E., Moore, David J. P., Norby, Richard J., Zaehle, Sönke, Anderson-Teixeira, Kristina J., Battipaglia, Giovanna, Brienen, Roel J. W., Cabugao, Kristine G., Cailleret, Maxime, Campbell, Elliott, Canadell, Josep G., Ciais, Philippe, Craig, Matthew E., Ellsworth, David S., Farquhar, Graham D., Fatichi, Simone, Fisher, Joshua B., Frank, David C., Graven, Heather, Gu, Lianhong, Haverd, Vanessa, Heilman, Kelly, Heimann, Martin, Hungate, Bruce A., Iversen, Colleen M., Joos, Fortunat, Jiang, Mingkai, Keenan, Trevor F., Knauer, Jürgen, Körner, Christian, Leshyk, Victor O., Leuzinger, Sebastian, Liu, Yao, MacBean, Natasha, Malhi, Yadvinder, McVicar, Tim R., Penuelas, Josep, Pongratz, Julia, Powell, A. Shafer, Riutta, Terhi, Sabot, Manon E. B., Schleucher, Juergen, Sitch, Stephen, Smith, William K., Sulman, Benjamin, Taylor, Benton, Terrer, César, Torn, Margaret S., Treseder, Kathleen K., Trugman, Anna T., Trumbore, Susan E., van Mantgem, Phillip J., Voelker, Steve L., Whelan, Mary E., and Zuidema, Pieter A.

Subjects
13. Climate action, 530 Physics, food and beverages, 15. Life on land
Abstract

Summary Atmospheric carbon dioxide concentration ([CO2]) is increasing, which increases leaf-scale photosynthesis and intrinsic water-use efficiency. These direct responses have the potential to increase plant growth, vegetation biomass, and soil organic matter; transferring carbon from the atmosphere into terrestrial ecosystems (a carbon sink). A substantial global terrestrial carbon sink would slow the rate of [CO2] increase and thus climate change. However, ecosystem CO2 responses are complex or confounded by concurrent changes in multiple agents of global change and evidence for a [CO2]-driven terrestrial carbon sink can appear contradictory. Here we synthesize theory and broad, multidisciplinary evidence for the effects of increasing [CO2] (iCO2) on the global terrestrial carbon sink. Evidence suggests a substantial increase in global photosynthesis since pre-industrial times. Established theory, supported by experiments, indicates that iCO2 is likely responsible for about half of the increase. Global carbon budgeting, atmospheric data, and forest inventories indicate a historical carbon sink, and these apparent iCO2 responses are high in comparison to experiments and predictions from theory. Plant mortality and soil carbon iCO2 responses are highly uncertain. In conclusion, a range of evidence supports a positive terrestrial carbon sink in response to iCO2, albeit with uncertain magnitude and strong suggestion of a role for additional agents of global change.

36. Integrating the evidence for a terrestrial carbon sink caused by increasing atmospheric CO2

Author

Philippe Ciais, Terhi Riutta, Margaret S. Torn, Kathleen K. Treseder, Phillip J. van Mantgem, Fortunat Joos, William K. Smith, Heather Graven, Trevor F. Keenan, Simone Fatichi, Stephen Sitch, Susan E. Trumbore, Belinda E. Medlyn, Lianhong Gu, Yao Liu, Anna T. Trugman, Juergen Schleucher, Elliott Campbell, Steve L. Voelker, Ana Bastos, Kristina J. Anderson-Teixeira, Pieter A. Zuidema, Mary E. Whelan, Mingkai Jiang, Martin G. De Kauwe, Ralph F. Keeling, Vanessa Haverd, David S. Ellsworth, Anthony P. Walker, Colleen M. Iversen, David J. P. Moore, Martin Heimann, Benton N. Taylor, César Terrer, Yadvinder Malhi, Tim R. McVicar, Julia Pongratz, Josep Peñuelas, David Frank, Katerina Georgiou, Josep G. Canadell, A. Shafer Powell, Matthew E. Craig, Manon Sabot, Roel J. W. Brienen, Victor O. Leshyk, Christian Körner, Sönke Zaehle, Sebastian Leuzinger, Richard J. Norby, Maxime Cailleret, Graham D. Farquhar, Benjamin N. Sulman, Giovanna Battipaglia, Natasha MacBean, Joshua B. Fisher, Kristine Grace Cabugao, Soumaya Belmecheri, Bruce A. Hungate, Sean M. McMahon, Kelly A. Heilman, Jürgen Knauer, Oak Ridge National Laboratory [Oak Ridge] (ORNL), UT-Battelle, LLC, Ludwig-Maximilians-Universität München (LMU), Scripps Institution of Oceanography (SIO - UC San Diego), University of California [San Diego] (UC San Diego), University of California (UC)-University of California (UC), Hawkesbury Institute for the Environment, Western Sydney University, Oak Ridge National Laboratory, Max Planck Institute for Biogeochemistry (MPI-BGC), Max-Planck-Gesellschaft, University of the Study of Campania Luigi Vanvitelli, School of Geography and the Environment [Oxford] (SoGE), University of Oxford, Risques, Ecosystèmes, Vulnérabilité, Environnement, Résilience (RECOVER), Aix Marseille Université (AMU)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), University of California (UC), Data61 [Canberra] (CSIRO), Australian National University (ANU)-Commonwealth Scientific and Industrial Research Organisation [Canberra] (CSIRO), 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), 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), U.S. Department of Energy Office of Science, Biological and Environmental Research. Grant Number: DE-AC05-00OR22725, Australian Research Council (ARC) Discovery Grant. Grant Number: DP190101823, US National Science Foundation Paleo Perspectives on Clima te Change Program, US Geological Survey Ecosystems Mission Area, NASA: NASA Terrestrial Ecosystems Grant 80NSSC19M 0103 and NASA Terrestrial Ecology Program IDS Award NNH 17AE86I, German Research Foundation’s Emmy Noether Program, Australian Research Council Centre of Excellence for Climate Extremes (CE170100023), VR, KAW and Kempe foundations, Lawrence Fellow award through Lawrence Livermore National Labor atory (LLNL) under contract DE-AC52-07NA27344 with the US Department of Energy and the LLNL-LDRD Program under Project no. 20-ERD-055, US Department of Energy, Office of Science under contract number DE-AC02-05CH11231, USDA National Institute of Food and Agriculture, Agricultural and Food Research Initiative Competitive Programme grant no.2018-67012-31496, University of California Laboratory Fees Research Program Award no. LFR-20-652467, European Project: 647204,H2020,ERC-2014-CoG,QUINCY(2015), European Project: 610028,EC:FP7:ERC,ERC-2013-SyG,IMBALANCE-P(2014), Walker, Anthony P., De Kauwe, Martin G., Bastos, Ana, Belmecheri, Soumaya, Georgiou, Katerina, Keeling, Ralph F., Mcmahon, Sean M., Medlyn, Belinda E., Moore, David J. P., Norby, Richard J., Zaehle, Sönke, Anderson‐teixeira, Kristina J., Battipaglia, Giovanna, Brienen, Roel J. W., Cabugao, Kristine G., Cailleret, Maxime, Campbell, Elliott, Canadell, Josep G., Ciais, Philippe, Craig, Matthew E., Ellsworth, David S., Farquhar, Graham D., Fatichi, Simone, Fisher, Joshua B., Frank, David C., Graven, Heather, Gu, Lianhong, Haverd, Vanessa, Heilman, Kelly, Heimann, Martin, Hungate, Bruce A., Iversen, Colleen M., Joos, Fortunat, Jiang, Mingkai, Keenan, Trevor F., Knauer, Jürgen, Körner, Christian, Leshyk, Victor O., Leuzinger, Sebastian, Liu, Yao, Macbean, Natasha, Malhi, Yadvinder, Mcvicar, Tim R., Penuelas, Josep, Pongratz, Julia, Powell, A. Shafer, Riutta, Terhi, Sabot, Manon E. B., Schleucher, Juergen, Sitch, Stephen, Smith, William K., Sulman, Benjamin, Taylor, Benton, Terrer, César, Torn, Margaret S., Treseder, Kathleen K., Trugman, Anna T., Trumbore, Susan E., Mantgem, Phillip J., Voelker, Steve L., Whelan, Mary E., and Zuidema, Pieter A.

Subjects
0106 biological sciences, CO fertilization, 010504 meteorology & atmospheric sciences, global carbon cycle, Physiology, chemistry.chemical_element, Plant Science, Atmospheric sciences, 01 natural sciences, Carbon cycle, chemistry.chemical_compound, land–atmosphere feedback, free-air CO enrichment (FACE), CO-fertilization hypothesis, CO2-fertilization hypothesis, Bosecologie en Bosbeheer, CO2 fertilization, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Carbon dioxide in Earth's atmosphere, Carbon sink, food and beverages, carbon dioxide, terrestrial ecosystems, Global change, Soil carbon, 15. Life on land, PE&RC, Forest Ecology and Forest Management, chemistry, 13. Climate action, Carbon dioxide, [SDE]Environmental Sciences, Environmental science, Terrestrial ecosystem, beta factor, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Carbon, 010606 plant biology & botany, free-air CO2 enrichment (FACE)
Abstract

International audience; Atmospheric carbon dioxide concentration ([CO 2 ]) is increasing, which increases leaf-scale photosynthesis and intrinsic water-use efficiency. These direct responses have the potential to increase plant growth, vegetation biomass, and soil organic matter; transferring carbon from the atmosphere into terrestrial ecosystems (a carbon sink). A substantial global terrestrial carbon sink would slow the rate of [CO 2] increase and thus climate change. However, ecosystem CO2 responses are complex or confounded by concurrent changes in multiple agents of global change and evidence for a [CO 2]-driven terrestrial carbon sink can appear contradictory. Here we synthesize theory and broad, multidisciplinary evidence for the effects of increasing [CO 2] (iCO 2) on the global terrestrial carbon sink. Evidence suggests a substantial increase in global photosynthesis since pre-industrial times. Established theory, supported by experiments, indicates that iCO 2 is likely responsible for about half of the increase. Global carbon budgeting, atmospheric data, and forest inventories indicate a historical carbon sink, and these apparent iCO 2 responses are high in comparison to experiments and predictions from theory. Plantmortality and soil carbon iCO 2 responses are highly uncertain. In conclusion, a range of evidence supports a positive terrestrial carbon sink in response to iCO2 , albeit with uncertain magnitude and strong suggestion of a role for additional agents of global change.

Published
2021

37. Integrating the evidence for a terrestrial carbon sink caused by increasing atmospheric CO 2 .

Author

Walker AP, De Kauwe MG, Bastos A, Belmecheri S, Georgiou K, Keeling RF, McMahon SM, Medlyn BE, Moore DJP, Norby RJ, Zaehle S, Anderson-Teixeira KJ, Battipaglia G, Brienen RJW, Cabugao KG, Cailleret M, Campbell E, Canadell JG, Ciais P, Craig ME, Ellsworth DS, Farquhar GD, Fatichi S, Fisher JB, Frank DC, Graven H, Gu L, Haverd V, Heilman K, Heimann M, Hungate BA, Iversen CM, Joos F, Jiang M, Keenan TF, Knauer J, Körner C, Leshyk VO, Leuzinger S, Liu Y, MacBean N, Malhi Y, McVicar TR, Penuelas J, Pongratz J, Powell AS, Riutta T, Sabot MEB, Schleucher J, Sitch S, Smith WK, Sulman B, Taylor B, Terrer C, Torn MS, Treseder KK, Trugman AT, Trumbore SE, van Mantgem PJ, Voelker SL, Whelan ME, and Zuidema PA

Subjects
Atmosphere, Carbon Cycle, Carbon Dioxide, Climate Change, Carbon Sequestration, Ecosystem
Abstract

Atmospheric carbon dioxide concentration ([CO 2 ]) is increasing, which increases leaf-scale photosynthesis and intrinsic water-use efficiency. These direct responses have the potential to increase plant growth, vegetation biomass, and soil organic matter; transferring carbon from the atmosphere into terrestrial ecosystems (a carbon sink). A substantial global terrestrial carbon sink would slow the rate of [CO 2 ] increase and thus climate change. However, ecosystem CO 2 responses are complex or confounded by concurrent changes in multiple agents of global change and evidence for a [CO 2 ]-driven terrestrial carbon sink can appear contradictory. Here we synthesize theory and broad, multidisciplinary evidence for the effects of increasing [CO 2 ] (iCO 2 ) on the global terrestrial carbon sink. Evidence suggests a substantial increase in global photosynthesis since pre-industrial times. Established theory, supported by experiments, indicates that iCO 2 is likely responsible for about half of the increase. Global carbon budgeting, atmospheric data, and forest inventories indicate a historical carbon sink, and these apparent iCO 2 responses are high in comparison to experiments and predictions from theory. Plant mortality and soil carbon iCO 2 responses are highly uncertain. In conclusion, a range of evidence supports a positive terrestrial carbon sink in response to iCO 2 , albeit with uncertain magnitude and strong suggestion of a role for additional agents of global change., (© 2020 The Authors New Phytologist Foundation © 2020 New Phytologist.)

Published
2021
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