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Maurice, L.; López, F.; Becerra, S.; Jamhoury, H.; Le Menach, K.; Dévier, M.-H.; Budzinski, H.; Prunier, J.; Juteau-Martineau, G.; Ochoa-Herrera, V.; Quiroga, D.; Schreck, E. |
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Title  |
Drinking water quality in areas impacted by oil activities in Ecuador: Associated health risks and social perception of human exposure |
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Journal Article |
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Year |
2019 |
Publication |
Science of the Total Environment |
Abbreviated Journal |
Sci. Total Environ. |
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690 |
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1203-1217 |
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Demineralized waters; Domestic waters; Hydrocarbons; Metal(loid)s; Oil activities; Social risk perception; Benzene refining; Health; Health risks; Hydrocarbons; Petroleum refineries; Petroleum refining; Polycyclic aromatic hydrocarbons; Potable water; Risk assessment; Risk perception; Toluene; Trace elements; Water quality; Water wells; Zinc; Arsenic concentration; Demineralized water; Domestic water; Information sources; Living conditions; Microbiological analysis; Natural backgrounds; Oil activities; Water distribution systems |
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The unregulated oil exploitation in the Northern Ecuadorian Amazon Region (NEAR), mainly from 1964 to the 90's, led to toxic compounds largely released into the environment. A large majority of people living in the Amazon region have no access to drinking water distribution systems and collects water from rain, wells or small streams. The concentrations of major ions, trace elements, PAHs (polycyclic aromatic hydrocarbons) and BTEX (benzene, toluene, ethylbenzene, xylenes) were analyzed in different water sources to evaluate the impacts of oil extraction and refining. Samples were taken from the NEAR and around the main refinery of the country (Esmeraldas Oil Refinery/State Oil Company of Ecuador) and were compared with domestic waters from the Southern region, not affected by petroleum activities. In most of the samples, microbiological analysis revealed a high level of coliforms representing significant health risks. All measured chemical compounds in waters were in line with national and international guidelines, except for manganese, zinc and aluminum. In several deep-water wells, close to oil camps, toluene concentrations were higher than the natural background while PAHs concentrations never exceeded individually 2 ng·L−1. Water ingestion represented 99% of the total exposure pathways for carcinogenic and non-carcinogenic elements (mainly zinc) in adults and children, while 20% to 49% of the Total Cancer Risk was caused by arsenic concentrations. The health index (HI) indicates acceptable chronic effects for domestic use according the US-EPA thresholds. Nevertheless, these limits do not consider the cocktail effects of metallic and organic compounds. Furthermore, they do not include the social determinants of human exposure, such as socio-economic living conditions or vulnerability. Most (72%) of interviewed families knew sanitary risks but a discrepancy was observed between knowledge and action: religious beliefs, cultural patterns, information sources, experience and emotions play an important role front to exposure. © 2019 |
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Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel HillNC 2759, United States |
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Elsevier B.V. |
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00489697 (Issn) |
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EcoFoG @ webmaster @ |
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877 |
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N'Guessan, A.E.; N'dja, J.K.; Yao, O.N.; Amani, B.H.K.; Gouli, R.G.Z.; Piponiot, C.; Zo-Bi, I.C.; Herault, B. |
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Title |
Drivers of biomass recovery in a secondary forested landscape of West Africa |
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Journal Article |
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2019 |
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Forest Ecology and Management |
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433 |
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325-331 |
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Biomass; Cultivation; Ecology; Recovery; Secondary recovery; Agricultural land; Bayesian frameworks; Diameter-at-breast heights; Forested landscapes; Neotropical forests; Old-growth forest; Physical environments; Secondary forests; Forestry; Dioscorea alata |
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The rapidly growing human population in West Africa has generated increasing demand for agricultural land and forest products. Consequently 90% of the original rainforest cover has now disappeared and the remainder is heavily fragmented and highly degraded. Although many studies have focused on carbon stocks and fluxes in intact African forests, little information exists on biomass recovery rates in secondary forests. We studied a chronosequence of 96 secondary and old-growth forest fragments (0.2 ha each) where 32.103 trees with Diameter at Breast Height > 2.5 cm have been censused. We modelled the biomass recovery trajectories in a time-explicit Bayesian framework and tested the effect on recovery rates of a large set of covariates related to the physical environment, plot history, and forest connectivity. Recovery rate trajectory is highly non-linear: recovery rates accelerated from 1 to 37 years, when biomass recovery reached 4.23 Mg /ha /yr, and decelerated afterwards. We predict that, on average, 10%, 25% and 50% of the old-growth forest biomass is respectively recovered 17, 30, and 51 years after abandonment. Recovery rates are strongly shaped by both the number of remnant trees (residuals of the former old-growth forest) and the previous crop cultivated before abandonment. The latter induced large differences in the time needed to recover 50% of an old-growth forest biomass: from 38 years for former Yam fields up to 86 years for former rice fields. Our results emphasize (i) the very slow recovery rates of West African forests, as compared to Neotropical forests (ii) the long-lasting impacts of past human activities and management choices on ecosystem biomass recovery in West African degraded forests. |
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Elsevier B.V. |
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03781127 (Issn) |
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EcoFoG @ webmaster @ |
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838 |
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Svensk, M.; Coste, S.; Gérard, B.; Gril, E.; Julien, F.; Maillard, P.; Stahl, C.; Leroy, C. |
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Title |
Drought effects on resource partition and conservation among leaf ontogenetic stages in epiphytic tank bromeliads |
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Journal Article |
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2020 |
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Physiologia Plantarum |
Abbreviated Journal |
Physiol. Plant. |
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170 |
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4 |
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488-507 |
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chlorophyll; nitrogen; water; Bromeliaceae; drought; metabolism; photosynthesis; plant leaf; Bromeliaceae; Chlorophyll; Droughts; Nitrogen; Photosynthesis; Plant Leaves; Water |
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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 |
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Laboratoire Ecologie Fonctionnelle et Environnement, Université de Toulouse, CNRS, Toulouse, 31062, France |
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Blackwell Publishing Ltd |
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00319317 (Issn) |
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PDF trop gros voir la documentaliste – merci |
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EcoFoG @ webmaster @ |
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943 |
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Phillips, O.L.; Aragao, L.E.O.C.; Lewis, S.L.; Fisher, J.B.; Lloyd, J.; Lopez-Gonzalez, G.; Malhi, Y.; Monteagudo, A.; Peacock, J.; Quesada, C.A.; van der Heijden, G.; Almeida, S.; Amaral, I.; Arroyo, L.; Aymard, G.; Baker, T.R.; Banki, O.; Blanc, L.; Bonal, D.; Brando, P.; Chave, J.; de Oliveira, A.C.A.; Cardozo, N.D.; Czimczik, C.I.; Feldpausch, T.R.; Freitas, M.A.; Gloor, E.; Higuchi, N.; Jimenez, E.; Lloyd, G.; Meir, P.; Mendoza, C.; Morel, A.; Neill, D.A.; Nepstad, D.; Patino, S.; Penuela, M.C.; Prieto, A.; Ramirez, F.; Schwarz, M.; Silva, J.; Silveira, M.; Thomas, A.S.; ter Steege, H.; Stropp, J.; Vasquez, R.; Zelazowski, P.; Davila, E.A.; Andelman, S.; Andrade, A.; Chao, K.J.; Erwin, T.; Di Fiore, A.; Honorio, E.; Keeling, H.; Killeen, T.J.; Laurance, W.F.; Cruz, A.P.; Pitman, N.C.A.; Vargas, P.N.; Ramirez-Angulo, H.; Rudas, A.; Salamao, R.; Silva, N.; Terborgh, J.; Torres-Lezama, A. |
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Title |
Drought Sensitivity of the Amazon Rainforest |
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Journal Article |
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2009 |
Publication |
Science |
Abbreviated Journal |
Science |
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323 |
Issue |
5919 |
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1344-1347 |
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Amazon forests are a key but poorly understood component of the global carbon cycle. If, as anticipated, they dry this century, they might accelerate climate change through carbon losses and changed surface energy balances. We used records from multiple long-term monitoring plots across Amazonia to assess forest responses to the intense 2005 drought, a possible analog of future events. Affected forest lost biomass, reversing a large long-term carbon sink, with the greatest impacts observed where the dry season was unusually intense. Relative to pre-2005 conditions, forest subjected to a 100-millimeter increase in water deficit lost 5.3 megagrams of aboveground biomass of carbon per hectare. The drought had a total biomass carbon impact of 1.2 to 1.6 petagrams (1.2 x 10(15) to 1.6 x 10(15) grams). Amazon forests therefore appear vulnerable to increasing moisture stress, with the potential for large carbon losses to exert feedback on climate change. |
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[Phillips, Oliver L.; Lewis, Simon L.; Lloyd, Jon; Lopez-Gonzalez, Gabriela; Peacock, Julie; Quesada, Carlos A.; van der Heijden, Geertje; Baker, Tim R.; Feldpausch, Ted R.; Gloor, Emanuel; Patino, Sandra; Schwarz, Michael; Chao, Kuo-Jung; Keeling, Helen] Univ Leeds, Sch Geog, Leeds LS2 9JT, W Yorkshire, England, Email: o.phillips@leeds.ac.uk |
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AMER ASSOC ADVANCEMENT SCIENCE |
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0036-8075 |
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ISI:000263876700042 |
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EcoFoG @ eric.marcon @ |
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120 |
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Maréchaux, I.; Bartlett, M.K.; Sack, L.; Baraloto, C.; Engel, J.; Joetzjer, E.; Chave, J. |
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Title |
Drought tolerance as predicted by leaf water potential at turgor loss point varies strongly across species within an Amazonian forest |
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Journal Article |
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Year |
2015 |
Publication |
Functional Ecology |
Abbreviated Journal |
Functional Ecology |
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29 |
Issue |
10 |
Pages |
1268-1277 |
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Keywords |
Climate change; French Guiana; Functional traits; Plant-water relations; Tropical trees; Wilting |
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Amazonian droughts are predicted to become increasingly frequent and intense, and the vulnerability of Amazonian trees has become increasingly documented. However, little is known about the physiological mechanisms and the diversity of drought tolerance of tropical trees due to the lack of quantitative measurements. Leaf water potential at wilting or turgor loss point (π<inf>tlp</inf>) is a determinant of the tolerance of leaves to drought stress and contributes to plant-level physiological drought tolerance. Recently, it has been demonstrated that leaf osmotic water potential at full hydration (π<inf>o</inf>) is tightly correlated with π<inf>tlp</inf>. Estimating π<inf>tlp</inf> from osmometer measurements of π<inf>o</inf> is much faster than the standard pressure-volume curve approach of π<inf>tlp</inf> determination. We used this technique to estimate π<inf>tlp</inf> for 165 trees of 71 species, at three sites within forests in French Guiana. Our data set represents a significant increase in available data for this trait for tropical tree species. Tropical trees showed a wider range of drought tolerance than previously found in the literature, π<inf>tlp</inf> ranging from -1·4 to -3·2 MPa. This range likely corresponds in part to adaptation and acclimation to occasionally extreme droughts during the dry season. Leaf-level drought tolerance varied across species, in agreement with the available published observations of species variation in drought-induced mortality. On average, species with a more negative π<inf>tlp</inf> (i.e. with greater leaf-level drought tolerance) occurred less frequently across the region than drought-sensitive species. Across individuals, π<inf>tlp</inf> correlated positively but weakly with leaf toughness (R2 = 0·22, P = 0·04) and leaf thickness (R2 = 0·03, P = 0·03). No correlation was detected with other functional traits (leaf mass per area, leaf area, nitrogen or carbon concentrations, carbon isotope ratio, sapwood density or bark thickness). The variability in π<inf>tlp</inf> among species indicates a potential for highly diverse species responses to drought within given forest communities. Given the weak correlations between π<inf>tlp</inf> and traditionally measured plant functional traits, vegetation models seeking to predict forest response to drought should integrate improved quantification of comparative drought tolerance among tree species. © 2015 British Ecological Society. |
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CNRM-GAME – URA1357, 42 avenue G. Coriolis, Toulouse, France |
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Cited By :1; Export Date: 12 October 2015 |
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EcoFoG @ webmaster @ |
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629 |
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Phillips, O.L.; van der Heijden, G.; Lewis, S.L.; Lopez-Gonzalez, G.; Aragao, L.E.O.C.; Lloyd, J.; Malhi, Y.; Monteagudo, A.; Almeida, S.; Davila, E.A.; Amaral, I.; Andelman, S.; Andrade, A.; Arroyo, L.; Aymard, G.; Baker, T.R.; Blanc, L.; Bonal, D.; de Oliveira, A.C.A.; Chao, K.J.; Cardozo, N.D.; da Costa, L.; Feldpausch, T.R.; Fisher, J.B.; Fyllas, N.M.; Freitas, M.A.; Galbraith, D.; Gloor, E.; Higuchi, N.; Honorio, E.; Jimenez, E.; Keeling, H.; Killeen, T.J.; Lovett, J.C.; Meir, P.; Mendoza, C.; Morel, A.; Vargas, P.N.; Patino, S.; Peh, K.S.H.; Cruz, A.P.; Prieto, A.; Quesada, C.A.; Ramirez, F.; Ramirez, H.; Rudas, A.; Salamao, R.; Schwarz, M.; Silva, J.; Silveira, M.; Slik, J.W.F.; Sonke, B.; Thomas, A.S.; Stropp, J.; Taplin, J.R.D.; Vasquez, R.; Vilanova, E. |
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Title |
Drought-mortality relationships for tropical forests |
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Journal Article |
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Year |
2010 |
Publication |
New Phytologist |
Abbreviated Journal |
New Phytol. |
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Volume |
187 |
Issue |
3 |
Pages |
631-646 |
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Amazon; Borneo; drought; lags mortality; RAINFOR; trees; tropics |
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The rich ecology of tropical forests is intimately tied to their moisture status. Multi-site syntheses can provide a macro-scale view of these linkages and their susceptibility to changing climates. Here, we report pan-tropical and regional-scale analyses of tree vulnerability to drought. We assembled available data on tropical forest tree stem mortality before, during, and after recent drought events, from 119 monitoring plots in 10 countries concentrated in Amazonia and Borneo. In most sites, larger trees are disproportionately at risk. At least within Amazonia, low wood density trees are also at greater risk of drought-associated mortality, independent of size. For comparable drought intensities, trees in Borneo are more vulnerable than trees in the Amazon. There is some evidence for lagged impacts of drought, with mortality rates remaining elevated 2 yr after the meteorological event is over. These findings indicate that repeated droughts would shift the functional composition of tropical forests toward smaller, denser-wooded trees. At very high drought intensities, the linear relationship between tree mortality and moisture stress apparently breaks down, suggesting the existence of moisture stress thresholds beyond which some tropical forests would suffer catastrophic tree mortality. |
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[Phillips, Oliver L.; van der Heijden, Geertje; Lewis, Simon L.; Lopez-Gonzalez, Gabriela; Lloyd, Jon; Baker, Tim R.; Chao, Kuo-Jung; Feldpausch, Ted R.; Fyllas, Nikolaos M.; Gloor, Emanuel; Honorio, Euridice; Keeling, Helen; Quesada, Carlos A.; Schwarz, Michael] Univ Leeds, Sch Geog, Leeds LS2 9JT, W Yorkshire, England, Email: o.phillips@leeds.ac.uk |
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WILEY-BLACKWELL PUBLISHING, INC |
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0028-646X |
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ISI:000280122500028 |
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EcoFoG @ eric.marcon @ |
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50 |
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Maréchaux, I.; Bonal, D.; Bartlett, M.K.; Burban, B.; Coste, S.; Courtois, E.A.; Dulormne, M.; Goret, J.-Y.; Mira, E.; Mirabel, A.; Sack, L.; Stahl, C.; Chave, J. |
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Title |
Dry-season decline in tree sapflux is correlated with leaf turgor loss point in a tropical rainforest |
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Journal Article |
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Year |
2018 |
Publication |
Functional Ecology |
Abbreviated Journal |
Funct Ecol |
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32 |
Issue |
10 |
Pages |
2285-2297 |
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drought tolerance; hydraulic conductance; sap flow; sapflux density; tropical trees; turgor loss point; water potential; wilting point |
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Water availability is a key determinant of forest ecosystem function and tree species distributions. While droughts are increasing in frequency in many ecosystems, including in the tropics, plant responses to water supply vary with species and drought intensity and are therefore difficult to model. Based on physiological first principles, we hypothesized that trees with a lower turgor loss point (pi-tlp), that is, a more negative leaf water potential at wilting, would maintain water transport for longer into a dry season. We measured sapflux density of 22 mature trees of 10 species during a dry season in an Amazonian rainforest, quantified sapflux decline as soil water content decreased and tested its relationship to tree pi-tlp, size and leaf predawn and midday water potentials measured after the onset of the dry season. The measured trees varied strongly in the response of water use to the seasonal drought, with sapflux at the end of the dry season ranging from 37 to 117% (on average 83 +/- 5 %) of that at the beginning of the dry season. The decline of water transport as soil dried was correlated with tree pi-tlp (Spearman's rho > 0.63), but not with tree size or predawn and midday water potentials. Thus, trees with more drought-tolerant leaves better maintained water transport during the seasonal drought. Our study provides an explicit correlation between a trait, measurable at the leaf level, and whole-plant performance under drying conditions. Physiological traits such as pi-tlp can be used to assess and model higher scale processes in response to drying conditions. |
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Wiley/Blackwell (10.1111) |
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0269-8463 |
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doi: 10.1111/1365-2435.13188 |
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EcoFoG @ webmaster @ |
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830 |
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Blanc, L.; Echard, M.; Herault, B.; Bonal, D.; Marcon, E.; Chave, J.; Baraloto, C. |
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Title |
Dynamics of aboveground carbon stocks in a selectively logged tropical forest |
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Journal Article |
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Year |
2009 |
Publication |
Ecological Applications |
Abbreviated Journal |
Ecol. Appl. |
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19 |
Issue |
6 |
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1397-1404 |
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aboveground biomass; carbon sequestration; deforestation; French Guiana; global change; timber stand improvement; tropical forests |
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The expansion of selective logging in tropical forests may be an important source of global carbon emissions. However, the effects of logging practices on the carbon cycle have never been quantified over long periods of time. We followed the fate of more than 60 000 tropical trees over 23 years to assess changes in aboveground carbon stocks in 48 1.56-ha plots in French Guiana that represent a gradient of timber harvest intensities, with and without intensive timber stand improvement (TSI) treatments to stimulate timber tree growth. Conventional selective logging led to emissions equivalent to more than a third of aboveground carbon stocks in plots without TSI (85 Mg C/ha), while plots with TSI lost more than one-half of aboveground carbon stocks (142 Mg C/ha). Within 20 years of logging, plots without TSI sequestered aboveground carbon equivalent to more than 80% of aboveground carbon lost to logging (-70.7 Mg C/ha), and our simulations predicted an equilibrium aboveground carbon balance within 45 years of logging. In contrast, plots with intensive TSI are predicted to require more than 100 years to sequester aboveground carbon lost to emissions. These results indicate that in some tropical forests aboveground carbon storage can be recovered within half a century after conventional logging at moderate harvest intensities. |
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[Bonal, Damien; Baraloto, Christopher] INRA, UMR Ecol Forets Guyane, Kourou 97379, French Guiana, Email: chris.baraloto@ecofog.gf |
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ECOLOGICAL SOC AMER |
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1051-0761 |
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ISI:000269075200003 |
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EcoFoG @ eric.marcon @ |
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105 |
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Author |
Orivel, J.; Lambs, L.; Male, P.J.G.; Leroy, C.; Grangier, J.; Otto, T.; Quilichini, A.; Dejean, A. |
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Title |
Dynamics of the association between a long-lived understory myrmecophyte and its specific associated ants |
Type |
Journal Article |
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Year |
2011 |
Publication |
Oecologia |
Abbreviated Journal |
Oecologia |
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Volume |
165 |
Issue |
2 |
Pages |
369-376 |
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Keywords |
Allomerus decemarticulatus; Hirtella physophora; Lifespan; Mutualism; Myrmecophyte |
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Abstract |
Myrmecophytic symbioses are widespread in tropical ecosystems and their diversity makes them useful tools for understanding the origin and evolution of mutualisms. Obligate ant-plants, or myrmecophytes, provide a nesting place, and, often, food to a limited number of plant-ant species. In exchange, plant-ants protect their host plants from herbivores, competitors and pathogens, and can provide them with nutrients. Although most studies to date have highlighted a similar global pattern of interactions in these systems, little is known about the temporal structuring and dynamics of most of these associations. In this study we focused on the association between the understory myrmecophyte Hirtella physophora (Chrysobalanaceae) and its obligate ant partner Allomerus decemarticulatus (Myrmicinae). An examination of the life histories and growth rates of both partners demonstrated that this plant species has a much longer lifespan (up to about 350 years) than its associated ant colonies (up to about 21 years). The size of the ant colonies and their reproductive success were strongly limited by the available nesting space provided by the host plants. Moreover, the resident ants positively affected the vegetative growth of their host plant, but had a negative effect on its reproduction by reducing the number of flowers and fruits by more than 50%. Altogether our results are important to understanding the evolutionary dynamics of ant-plant symbioses. The highly specialized interaction between long-lived plants and ants with a shorter lifespan produces an asymmetry in the evolutionary rates of the interaction which, in return, can affect the degree to which the interests of the two partners converge. |
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Address |
[Orivel, Jerome; Leroy, Celine; Quilichini, Angelique; Dejean, Alain] CNRS, UMR Ecol Forets Guyane, F-97379 Kourou, France, Email: jerome.orivel@ecofog.gf |
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Springer |
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ISSN |
0029-8549 |
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Notes |
ISI:000286224900012 |
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no |
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Call Number |
EcoFoG @ webmaster @ |
Serial |
295 |
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Author |
Céréghino, R.; Corbara, B.; Leroy, C.; Carrias, J.-F. |
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Title |
Ecological determinants of community structure across the trophic levels of freshwater food webs: a test using bromeliad phytotelmata |
Type |
Journal Article |
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Year |
2020 |
Publication |
Hydrobiologia |
Abbreviated Journal |
Hydrobiologia |
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Volume |
847 |
Issue |
2 |
Pages |
391-402 |
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Keywords |
Environmental filtering; Functional group; Neotropical; Niche; Trophic interactions; alga; assembly rule; bacterium; community structure; ecological modeling; environmental conditions; food web; freshwater ecosystem; functional group; Neotropic Ecozone; niche; protozoan; taxonomy; trophic interaction; trophic level; algae; Invertebrata; Protozoa |
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Abstract |
Understanding the relative importance of habitat and biotic drivers on community assembly across food web components is an important step towards predicting the consequences of environmental changes. Because documenting entire food webs is often impractical, this question has been only partially investigated. Here, we partitioned variation in species assemblages of the major components of tank bromeliad food webs (bacteria, algae, protozoans, detritivorous and predatory invertebrates) into habitat and biotic determinants and examined the influence of habitat variables and predator or prey abundance on all taxonomic assemblages. Ecological determinism of assemblage structure ranged from weak in bacteria (< 10% of the explained variance) to strong in predatory invertebrates (90%). Habitat features and canopy openness significantly influenced species assemblages; however, prey or predator density had far and away the most significant structuring effects. If biotic forces are at least as important as the abiotic forces while the importance of stochasticity declines towards upper trophic levels, then trophic levels could respond differently to natural or anthropogenic disturbance and to shifts in species distributions. The effects of such differential responses on food web reconfiguration, however, remain to be elucidated. © 2019, Springer Nature Switzerland AG. |
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Address |
UMR EcoFoG (AgroParisTech, CIRAD, CNRS, INRA, Université de Guyane, Université des Antilles), Kourou, 97310, France |
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Springer |
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00188158 (Issn) |
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EcoFoG @ webmaster @ |
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996 |
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