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Author Mahoui,Sihem ; Moulay, Mohamed Said ; Omrane, Abdennebi doi  openurl
  Title Finite element approach to linear parabolic pointwise control problems of incomplete data Type Journal Article
  Year 2020 Publication International Journal of Systems Science Abbreviated Journal  
  Volume 51 Issue 14 Pages 2597-2609  
  Keywords Optimal control problem ; low-regret control ; pointwise control ; finite element method ; a priori error estimates  
  Abstract In this paper we give a priori error estimates for finite element approximations of linear parabolicproblems with pointwise control and incomplete data. We discretise the optimal control problemby using piecewise linear and continuous finite elements for the space discretisation of the state,and we use the backward Euler scheme for time discretisation. We prove a priori error estimates forthe state, the adjoint-state as well as for the low-regret pointwise optimal control.  
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  Corporate Author Thesis  
  Publisher TAYLOR & FRANCIS LTD Place of Publication Editor  
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  Area Expedition Conference  
  Notes Approved no  
  Call Number (down) EcoFoG @ webmaster @ Serial 935  
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Author Van Langenhove, Leandro ; Verryckt, Lore T. ; Stahl, Clement ; Courtois, Elodie A. ; Urbina, Ifigenia ; Grau, Oriol ; Asensio, Dolores ; Peguero, Guille ; Margalef, Olga ; Freycon, Vincent ; Penuelas, Josep ; Janssens, Ivan A. doi  openurl
  Title Soil nutrient variation along a shallow catena in Paracou, French Guiana Type Journal Article
  Year 2021 Publication Soil Research Abbreviated Journal  
  Volume 59 Issue 2 Pages 130  
  Keywords French Guiana, lowland tropical forest, Paracou, phosphorus, topography, water drainage.  
  Abstract Tropical forests are generally considered to stand upon nutrient-poor soils, but soil nutrient concentrations and availabilities can vary greatly at local scale due to topographic effects on erosion and water drainage. In this study we physically and chemically characterised the soils of 12 study plots situated along a catena with a shallow slope in a tropical rainforest in French Guiana both during the wet and the dry season to evaluate seasonal differences. Soils along the catena were all Acrisols, but differed strongly in their water drainage flux. Over time, this differential drainage has led to differences in soil texture and mineral composition, affecting the adsorption of various nutrients, most importantly phosphorus. The more clayey soils situated on the slope of the catena had higher total concentrations of carbon, nitrogen, phosphorus and several micronutrients, while extractable nutrient concentrations were highest in the sandiest soils situated at the bottom of the catena. We found that carbon, nitrogen and extractable nutrients all varied seasonally, especially in the surface soil layer. These results are interesting because they show that, even at the local scale, small differences in topography can lead to large heterogeneity in nutrient concentrations, which can have large impacts on plant and microbial community organisation at the landscape level.  
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  Corporate Author Thesis  
  Publisher CSIRO Publishing Place of Publication Editor  
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  Area Expedition Conference  
  Notes Approved no  
  Call Number (down) EcoFoG @ webmaster @ Serial 1042  
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Author Mirabel, Ariane ; Marcon, Eric ; Hérault, Bruno doi  openurl
  Title 30 Years of postdisturbance recruitment in a Neotropical forest Type Journal Article
  Year 2021 Publication Ecology and Evolution Abbreviated Journal  
  Volume 11 Issue 21 Pages 14448-14458  
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  Publisher John Wiley & Sons, Ltd (10.1111) Place of Publication Editor  
  Language Summary Language Original Title  
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  Area Expedition Conference  
  Notes Approved no  
  Call Number (down) EcoFoG @ webmaster @ Serial 1043  
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Author Migliavacca, Mirco ; Musavi, Talie ; Mahecha, Miguel D. ; Nelson, Jacob A. ; Knauer, Jurgen ; Baldocchi, Dennis D. ; Perez-Priego, Oscar ; Christiansen, Rune ; Peters, Jonas ; Anderson, Karen ; Bahn, Michael ; Black, T. Andrew ; Blanken, Peter D. ; and all .................. doi  openurl
  Title The three major axes of terrestrial ecosystem function Type Journal Article
  Year 2021 Publication Nature Abbreviated Journal  
  Volume 598 Issue 7881 Pages 468-472  
  Keywords  
  Abstract The leaf economics spectrum1,2 and the global spectrum of plant forms and functions3 revealed fundamental axes of variation in plant traits, which represent different ecological strategies that are shaped by the evolutionary development of plant species2. Ecosystem functions depend on environmental conditions and the traits of species that comprise the ecological communities4. However, the axes of variation of ecosystem functions are largely unknown, which limits our understanding of how ecosystems respond as a whole to anthropogenic drivers, climate and environmental variability4,5. Here we derive a set of ecosystem functions6 from a dataset of surface gas exchange measurements across major terrestrial biomes. We find that most of the variability within ecosystem functions (71.8%) is captured by three key axes. The first axis reflects maximum ecosystem productivity and is mostly explained by vegetation structure. The second axis reflects ecosystem water-use strategies and is jointly explained by variation in vegetation height and climate. The third axis, which represents ecosystem carbon-use efficiency, features a gradient related to aridity, and is explained primarily by variation in vegetation structure. We show that two state-of-the-art land surface models reproduce the first and most important axis of ecosystem functions. However, the models tend to simulate more strongly correlated functions than those observed, which limits their ability to accurately predict the full range o  
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  Publisher Nature Publishing Group Place of Publication Editor  
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  Area Expedition Conference  
  Notes Approved no  
  Call Number (down) EcoFoG @ webmaster @ Serial 1044  
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Author Legeay, J.; Husson, C.; Boudier, B.; Louisanna, E.; Baraloto, C.; Schimann, H.; Marcais, B.; Buée, M. doi  openurl
  Title Surprising low diversity of the plant pathogen Phytophthora in Amazonian forests Type Journal Article
  Year 2020 Publication Environmental Microbiology Abbreviated Journal Environ. Microbiol.  
  Volume 22 Issue 12 Pages 5019-5032  
  Keywords  
  Abstract The genus Phytophthora represents a group of plant pathogens with broad global distribution. The majority of them cause the collar and root-rot of diverse plant species. Little is known about Phytophthora communities in forest ecosystems, especially in the Neotropical forests where natural enemies could maintain the huge plant diversity via negative density dependence. We characterized the diversity of soil-borne Phytophthora communities in the North French Guiana rainforest and investigated how they are structured by host identity and environmental factors. In this little-explored habitat, 250 soil cores were sampled from 10 plots hosting 10 different plant families across three forest environments (Terra Firme, Seasonally Flooded and White Sand). Phytophthora diversity was studied using a baiting approach and metabarcoding (High-Throughput Sequencing) on environmental DNA extracted from both soil samples and baiting-leaves. These three approaches revealed very similar communities, characterized by an unexpected low diversity of Phytophthora species, with the dominance of two cryptic species close to Phytophthora heveae. As expected, the Phytophthora community composition of the French Guiana rainforest was significantly impacted by the host plant family and environment. However, these plant pathogen communities are very small and are dominated by generalist species, questioning their potential roles as drivers of plant diversity in these Amazonian forests. © 2020 Society for Applied Microbiology and John Wiley & Sons Ltd.  
  Address International Center for Tropical Botany, Department of Biological Sciences, Florida International University, Miami, FL 33199, United States  
  Corporate Author Thesis  
  Publisher Blackwell Publishing Ltd Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 14622912 (Issn) ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number (down) EcoFoG @ webmaster @ Serial 940  
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Author Llusia, Joan ; Asensio, Dolores ; Sardans, Jordi ; Filella, Iolanda ; Peguero, Guille ; Grau, Oriol ; Ogaya, Roma ; Gargallo-Garriga, Albert ; Verryckt, Lore T. ; Van Langenhove, Leandro ; Brechet, Laëtitia M. ; Courtois, Elodie A. ; Stahl, Clément ; Janssens, Ivan A. ; Penuelas, Josep doi  openurl
  Title Contrasting nitrogen and phosphorus fertilization effects on soil terpene exchanges in a tropical forest Type Journal Article
  Year 2021 Publication Science of the Total Environment Abbreviated Journal  
  Volume 802 Issue Pages 149769  
  Keywords  
  Abstract Production, emission, and absorption of biogenic volatile organic compounds (BVOCs) in ecosystem soils and associated impacts of nutrient availability are unclear; thus, predictions of effects of global change on source-sink dynamic under increased atmospheric N deposition and nutrition imbalances are limited. Here, we report the dynamics of soil BVOCs under field conditions from two undisturbed tropical rainforests from French Guiana. We analyzed effects of experimental soil applications of nitrogen (N), phosphorus (P), and N + P on soil BVOC exchanges (in particular of total terpenes, monoterpenes, and sesquiterpenes), to determine source and sink dynamics between seasons (dry and wet) and elevations (upper and lower elevations corresponding to top of the hills (30 m high) and bottom of the valley). We identified 45 soil terpenoids compounds emitted to the atmosphere, comprising 26 monoterpenes and 19 sesquiterpenes; of these, it was possible to identify 13 and 7 compounds, respectively. Under ambient conditions, soils acted as sinks of these BVOCs, with greatest soil uptake recorded for sesquiterpenes at upper elevations during the wet season (-282 μg m-2 h-1). Fertilization shifted soils from a sink to source, with greatest levels of terpene emissions recorded at upper elevations during the wet season, following the addition of N (monoterpenes: 406 μg m-2 h-1) and P (sesquiterpenes: 210 μg m-2 h-1). Total soil terpene emission rates were negatively correlated with total atmospheric terpene concentrations. These results indicate likely shifts in tropical soils from sink to source of atmospheric terpenes under projected increases in N deposition under global change, with potential impacts on regional-scale atmospheric chemistry balance and ecosystem function.  
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  Publisher Elsevier Place of Publication Editor  
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  Area Expedition Conference  
  Notes Approved no  
  Call Number (down) EcoFoG @ webmaster @ Serial 1033  
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Author Céréghino, R.; Françoise, L.; Bonhomme, C.; Carrias, J.-F.; Compin, A.; Corbara, B.; Jassey, V.; Leflaive, J.; Rota, T.; Farjalla, V.; Leroy, C. doi  openurl
  Title Desiccation resistance traits predict freshwater invertebrate survival and community response to drought scenarios in a Neotropical ecosystem Type Journal Article
  Year 2020 Publication Ecological Indicators Abbreviated Journal Ecol. Indic.  
  Volume 119 Issue 106839 Pages  
  Keywords Climate change; Functional traits; Lt50; Macroinvertebrates; Rainforests; Biodiversity; Climate change; Driers (materials); Drought; Environmental management; Population statistics; Tanks (containers); Water; Aquatic invertebrates; Climate change adaptation; Controlled conditions; Environmental managers; Freshwater biodiversity; Freshwater invertebrates; Future climate scenarios; Laboratory conditions; Aquatic organisms; aquatic community; biodiversity; climate change; cuticle; desiccation; drought stress; invertebrate; Neotropical Region; population size; survival; French Guiana; Invertebrata  
  Abstract The intensification of dry seasons is a major threat to freshwater biodiversity in Neotropical regions. Little is known about resistance to drying stress and the underpinning traits in Neotropical freshwater species, so we don't know whether desiccation resistance allows to anticipate shifts in biological diversity under future climate scenarios. Here, we used the aquatic invertebrates that live in the rainwater-filled leaves of tank bromeliads, to examine the extent to which desiccation resistance of species measured in the laboratory predicts community response to drought intensification in nature. We measured desiccation resistance in 17 invertebrate species (>90% of the biomass usually found in bromeliads of French Guiana) by recording the median lethal time (LT50) of experimental populations exposed to controlled conditions of residual moisture. In the field, we placed rainshelters above tank bromeliads to emulate drought scenarios ranging from the ambient norm to IPCC scenarios and extreme events, and we recorded the response of functional community structure. LT50 ranged from 4.18 to 19.06 days, and was related to cuticle content and dry body mass. Among other functional indicators that represent strategies to optimize resource use under stressful conditions (e.g., habitat use, trophic specialization), LT50 was the best predictor of community structure responses along a gradient of emulated drought intensities. Therefore, species’ LT50s measured under laboratory conditions can be used to forecast aquatic community response to drying stress in nature. Anticipating how species will cope with drought has never been more important for environmental managers to support climate change adaptation. We show that desiccation resistance in freshwater invertebrates is a key indicator of potential population size and local–global range shifts, and this could be especially true in the Neotropics where species have narrow physiological tolerances for climatic variation. © 2020 Elsevier Ltd  
  Address ECOFOG, AgroParisTech, CIRAD, CNRS, INRA, Université de Guyane, Université des Antilles, Campus Agronomique, Kourou, 97379, France  
  Corporate Author Thesis  
  Publisher Elsevier B.V. Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1470160x (Issn) ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number (down) EcoFoG @ webmaster @ Serial 941  
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Author Poorter, Laurens ; Craven, Dylan ; Jakovac, Catarina C. ; van der Sande, Masha T. ; Amissah, Lucy ; Bongers, Frans ; Chazdon, Robin ; Farrioir, Caroline E. ; Kambach, Stephan ; Meave, Jorge A. ; Munoz, Rodrigo ; Norden, Natalia ; Ruger, Nadja ; van Breugel, Michiel ; et all ...... doi  openurl
  Title Multidimensional tropical forest recovery Type Journal Article
  Year 2021 Publication Science Abbreviated Journal  
  Volume 374 Issue 6573 Pages 1370-1376  
  Keywords  
  Abstract Tropical forests disappear rapidly because of deforestation, yet they have the potential to regrow naturally on abandoned lands. We analyze how 12 forest attributes recover during secondary succession and how their recovery is interrelated using 77 sites across the tropics. Tropical forests are highly resilient to low-intensity land use; after 20 years, forest attributes attain 78% (33 to 100%) of their old-growth values. Recovery to 90% of old-growth values is fastest for soil (<1 decade) and plant functioning (<2.5 decades), intermediate for structure and species diversity (2.5 to 6 decades), and slowest for biomass and species composition (>12 decades). Network analysis shows three independent clusters of attribute recovery, related to structure, species diversity, and species composition. Secondary forests should be embraced as a low-cost, natural solution for ecosystem restoration, climate change mitigation, and biodiversity conservation.  
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  Corporate Author Thesis  
  Publisher American association for the advancement of science Place of Publication Editor  
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  Notes Approved no  
  Call Number (down) EcoFoG @ webmaster @ Serial 1039  
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Author Van Langenhove, Leandro ; Depaepe, Thomas ; Verryckt, Lore T. ; Vallicrosa, Helena ; Fuchslueger, Lucia ; Lugli, Laynara F. ; Bréchet, Laëtitia M. ; Ogaya, Roma ; Llusia, Joan ; Urbina, Ifigenia ; Gargallo-Garriga, Albert ; Grau, Oriol ; Richter, Andreas ; Penuelas, Josep ; Van Der Straeten, Dominique ; August Janssens, Ivan A. doi  openurl
  Title Impact of Nutrient Additions on Free-Living Nitrogen Fixation in Litter and Soil of Two French-Guianese Lowland Tropical Forests Type Journal Article
  Year 2021 Publication JGR Biogeosciences Abbreviated Journal  
  Volume 126 Issue 7 Pages e2020JG006023  
  Keywords  
  Abstract In tropical forests, free-living Biological nitrogen (N) fixation (BNF) in soil and litter tends to decrease when substrate N concentrations increase, whereas increasing phosphorus (P) and molybdenum (Mo) soil and litter concentrations have been shown to stimulate free-living BNF rates. Yet, very few studies explored the effects of adding N, P, and Mo together in a single large-scale fertilization experiment, which would teach us which of these elements constrain or limit BNF activities. At two distinct forest sites in French Guiana, we performed a 3-year in situ nutrient addition study to explore the effects of N, P, and Mo additions on leaf litter and soil BNF. Additionally, we conducted a short-term laboratory study with the same nutrient addition treatments (+N, +N+P, +P, +Mo, and +P+Mo). We found that N additions alone suppressed litter free-living BNF in the field, but not in the short-term laboratory study, while litter free-living BNF remained unchanged in response to N+P additions. Additionally, we found that P and P+Mo additions stimulated BNF in leaf litter, both in the field and in the lab, while Mo alone yielded no changes. Soil BNF increased with P and P+Mo additions in only one of the field sites, while in the other site soil BNF increased with Mo and P+Mo additions. We concluded that increased substrate N concentrations suppress BNF. Moreover, both P and Mo have the potential to limit free-living BNF in these tropical forests, but the balance between P versus Mo limitation is determined by site-specific characteristics of nutrient supply and demand.  
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  Publisher American Geophysical Union Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
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  Notes Approved no  
  Call Number (down) EcoFoG @ webmaster @ Serial 1040  
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Author Svensk, M.; Coste, S.; Gérard, B.; Gril, E.; Julien, F.; Maillard, P.; Stahl, C.; Leroy, C. doi  openurl
  Title Drought effects on resource partition and conservation among leaf ontogenetic stages in epiphytic tank bromeliads Type Journal Article
  Year 2020 Publication Physiologia Plantarum Abbreviated Journal Physiol. Plant.  
  Volume 170 Issue 4 Pages 488-507  
  Keywords chlorophyll; nitrogen; water; Bromeliaceae; drought; metabolism; photosynthesis; plant leaf; Bromeliaceae; Chlorophyll; Droughts; Nitrogen; Photosynthesis; Plant Leaves; Water  
  Abstract Studying the response to drought stress of keystone epiphytes such as tank bromeliads is essential to better understand their resistance capacity to future climate change. The objective was to test whether there is any variation in the carbon, water and nutrient status among different leaf ontogenetic stages in a bromeliad rosette subjected to a gradient of drought stress. We used a semi-controlled experiment consisting in a gradient of water shortage in Aechmea aquilega and Lutheria splendens. For each bromeliad and drought treatment, three leaves were collected based on their position in the rosette and several functional traits related to water and nutrient status, and carbon metabolism were measured. We found that water status traits (relative water content, leaf succulence, osmotic and midday water potentials) and carbon metabolism traits (carbon assimilation, maximum quantum yield of photosystem II, chlorophyll and starch contents) decreased with increasing drought stress, while leaf soluble sugars and carbon, nitrogen and phosphorus contents remained unchanged. The different leaf ontogenetic stages showed only marginal variations when subjected to a gradient of drought. Resources were not reallocated between different leaf ontogenetic stages but we found a reallocation of soluble sugars from leaf starch reserves to the root system. Both species were capable of metabolic and physiological adjustments in response to drought. Overall, this study advances our understanding of the resistance of bromeliads faced with increasing drought stress and paves the way for in-depth reflection on their strategies to cope with water shortage. © 2020 Scandinavian Plant Physiology Society  
  Address Laboratoire Ecologie Fonctionnelle et Environnement, Université de Toulouse, CNRS, Toulouse, 31062, France  
  Corporate Author Thesis  
  Publisher Blackwell Publishing Ltd Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 00319317 (Issn) ISBN Medium  
  Area Expedition Conference  
  Notes PDF trop gros voir la documentaliste – merci Approved no  
  Call Number (down) EcoFoG @ webmaster @ Serial 943  
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