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Stahl, C.; Burban, B.; Goret, J.Y.; Bonal, D. |
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Title |
Seasonal variations in stem CO(2) efflux in the Neotropical rainforest of French Guiana |
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Journal Article |
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Year |
2011 |
Publication |
Annals of Forest Science |
Abbreviated Journal |
Ann. For. Sci. |
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Volume |
68 |
Issue |
4 |
Pages |
771-782 |
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Keywords |
Tropical rainforest; Stem CO(2) efflux; Soil water content; Terra Firme forest; Seasonally flooded forest |
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Abstract |
Introduction Stem CO(2) efflux (E (s)) is a significant component of total ecosystem respiration, but there is only scant information on seasonal variations in E (s) in tropical rainforests and on the main factors explaining these variations. Methods We conducted a comprehensive 18-month study in French Guiana to try to better understand which environmental factors contribute to seasonal variations in E (s) in two habitats differing in soil water conditions. Results In both habitats, large seasonal variations in E (s) were observed for most trees. The main variations occurred during climatic transition periods and were consistent with seasonal variations in soil and total ecosystem respiration. Discussion Seasonal variations in atmospheric conditions, including air temperature, did not explain seasonal variations in E (s). In contrast, seasonal variations in surface soil water content clearly induced seasonal variations in E (s) in each habitat. Both soil drought and flooded conditions induced a decrease in E (s). Conclusion Our results emphasize the need to integrate the influence of soil water content on E (s) into global models that simulate the response of forest ecosystem fluxes to climate changes. |
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[Bonal, D] INRA, UMR INRA UHP Ecol & Ecophysiol Forestiere 1137, F-54280 Champenoux, France, Email: bonal@nancy.inra.fr |
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Springer France |
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1286-4560 |
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WOS:000292553400011 |
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EcoFoG @ webmaster @ |
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327 |
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Author |
Zalamea, P.C.; Munoz, F.; Stevenson, P.R.; Paine, C.E.T.; Sarmiento, C.; Sabatier, D.; Heuret, P. |
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Title |
Continental-scale patterns of Cecropia reproductive phenology: evidence from herbarium specimens |
Type |
Journal Article |
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Year |
2011 |
Publication |
Proceedings Of The Royal Society B-Biological Sciences |
Abbreviated Journal |
Proc. R. Soc. B-Biol. Sci. |
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Volume |
278 |
Issue |
1717 |
Pages |
2437-2445 |
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Keywords |
climate seasonality; reproductive patterns; Fourier spectral and cospectral analyses; herbarium collections; Neotropics; pioneer plants |
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Abstract |
Plant phenology is concerned with the timing of recurring biological events. Though phenology has traditionally been studied using intensive surveys of a local flora, results from such surveys are difficult to generalize to broader spatial scales. In this study, contrastingly, we assembled a continental-scale dataset of herbarium specimens for the emblematic genus of Neotropical pioneer trees, Cecropia, and applied Fourier spectral and cospectral analyses to investigate the reproductive phenology of 35 species. We detected significant annual, sub-annual and continuous patterns, and discuss the variation in patterns within and among climatic regions. Although previous studies have suggested that pioneer species generally produce flowers continually throughout the year, we found that at least one third of Cecropia species are characterized by clear annual flowering behaviour. We further investigated the relationships between phenology and climate seasonality, showing strong associations between phenology and seasonal variations in precipitation and temperature. We also verified our results against field survey data gathered from the literature. Our findings indicate that herbarium material is a reliable resource for use in the investigation of large-scale patterns in plant phenology, offering a promising complement to local intensive field studies. |
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[Zalamea, PC; Sabatier, D] IRD, UMR AMAP, F-34000 Montpellier, France, Email: camilozalamea@gmail.com |
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Royal Soc |
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0962-8452 |
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WOS:000292592000005 |
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EcoFoG @ webmaster @ |
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328 |
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Bremaud, I.; Amusant, N.; Minato, K.; Gril, J.; Thibaut, B. |
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Title |
Effect of extractives on vibrational properties of African Padauk (Pterocarpus soyauxii Taub.) |
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Journal Article |
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Year |
2011 |
Publication |
Wood Science and Technology |
Abbreviated Journal |
Wood Sci. Technol. |
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Volume |
45 |
Issue |
3 |
Pages |
461-472 |
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Abstract |
Extractives can affect the vibrational properties tan delta (damping coefficient) and E'/rho (specific Young's modulus), but this is highly dependent on species, compounds, and cellular locations. This paper investigates such effects for African Padauk (Pterocarpus soyauxii Taub.), a tropical hardwood with high extractives content and a preferred material for xylophones. Five groups of 26 heartwood specimens with large, yet comparable, ranges in vibrational properties were extracted in different solvents. Changes in vibrational properties were set against yields of extracts and evaluation of their cellular location. Methanol (ME) reached most of the compounds (13%), located about half in lumen and half in cell-wall. Water solubility was extremely low. tan delta and E'/rho were very strongly related (R (2) a parts per thousand yen 0.93), but native wood had abnormally low values of tan delta, while extraction shifted this relation towards higher tan delta values. ME extracted heartwood became in agreement with the average of many species, and close to sapwood. Extractions increased tan delta as much as 60%, irrespective of minute moisture changes or initial properties. Apparent E'/rho was barely changed (+2% to -4%) but, after correcting the mass contribution of extracts, it was in fact slightly reduced (down to -10% for high E'/rho), and increasingly so for specimens with low initial values of E'/rho. |
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Address |
[Bremaud, I; Minato, K] Kyoto Prefectural Univ, Lab Forest Resource Circulating Circles, Grad Sch Life & Environm Sci, Kyoto 6068522, Japan, Email: iris_bremaud@hotmail.com |
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Springer |
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0043-7719 |
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WOS:000292550700005 |
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no |
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EcoFoG @ webmaster @ |
Serial |
329 |
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Bonal, D.; Ponton, S.; Le Thiec, D.; Richard, B.; Ningre, N.; Herault, B.; Ogee, J.; Gonzalez, S.; Pignal, M.; Sabatier, D.; Guehl, J.M. |
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Title |
Leaf functional response to increasing atmospheric CO(2) concentrations over the last century in two northern Amazonian tree species: a historical delta(13)C and delta(18)O approach using herbarium samples |
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Journal Article |
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Year |
2011 |
Publication |
Plant Cell and Environment |
Abbreviated Journal |
Plant Cell Environ. |
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Volume |
34 |
Issue |
8 |
Pages |
1332-1344 |
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Keywords |
carbon isotope composition; environmental change; herbarium; oxygen isotope composition; photosynthesis; stomata; tropical rainforests |
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Abstract |
We assessed the extent of recent environmental changes on leaf morphological (stomatal density, stomatal surface, leaf mass per unit area) and physiological traits (carbon isotope composition, delta(13)C(leaf), and discrimination, Delta(13)C(leaf), oxygen isotope composition, delta(18)O(leaf)) of two tropical rainforest species (Dicorynia guianensis; Humiria balsamifera) that are abundant in the Guiana shield (Northern Amazonia). Leaf samples were collected in different international herbariums to cover a 200 year time-period (1790-2004) and the whole Guiana shield. Using models describing carbon and oxygen isotope fractionations during photosynthesis, different scenarios of change in intercellular CO(2) concentrations inside the leaf (C(i)), stomatal conductance (g), and photosynthesis (A) were tested in order to understand leaf physiological response to increasing air CO(2) concentrations (C(a)). Our results confirmed that both species displayed physiological response to changing C(a). For both species, we observed a decrease of about 1.7% in delta(13)C(leaf) since 1950, without significant change in Delta(13)C(leaf) and leaf morphological traits. Furthermore, there was no clear change in delta(18)O(leaf) for Humiria over this period. Our simulation approach revealed that an increase in A, rather than a decrease in g, explained the observed trends for these tropical rainforest species, allowing them to maintain a constant ratio of C(i)/C(a). |
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Address |
[Bonal, D] INRA, UMR Ecofog, F-97387 Kourou, France, Email: bonal@nancy.inra.fr |
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Wiley-Blackwell |
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0140-7791 |
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Notes |
WOS:000292698900010 |
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no |
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EcoFoG @ webmaster @ |
Serial |
330 |
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Author |
Coste, S.; Roggy, J.C.; Schimann, H.; Epron, D.; Dreyer, E. |
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A cost-benefit analysis of acclimation to low irradiance in tropical rainforest tree seedlings: leaf life span and payback time for leaf deployment |
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Journal Article |
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Year |
2011 |
Publication |
Journal of Experimental Botany |
Abbreviated Journal |
J. Exp. Bot. |
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Volume |
62 |
Issue |
11 |
Pages |
3941-3955 |
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Keywords |
Carbon balance; construction cost; functional diversity; leaf life span; payback time; photosynthesis; tropical rainforest |
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Abstract |
The maintenance in the long run of a positive carbon balance under very low irradiance is a prerequisite for survival of tree seedlings below the canopy or in small gaps in a tropical rainforest. To provide a quantitative basis for this assumption, experiments were carried out to determine whether construction cost (CC) and payback time for leaves and support structures, as well as leaf life span (i) differ among species and (ii) display an irradiance-elicited plasticity. Experiments were also conducted to determine whether leaf life span correlates to CC and payback time and is close to the optimal longevity derived from an optimization model. Saplings from 13 tropical tree species were grown under three levels of irradiance. Specific-CC was computed, as well as CC scaled to leaf area at the metamer level. Photosynthesis was recorded over the leaf life span. Payback time was derived from CC and a simple photosynthesis model. Specific-CC displayed only little interspecific variability and irradiance-elicited plasticity, in contrast to CC scaled to leaf area. Leaf life span ranged from 4 months to > 26 months among species, and was longest in seedlings grown under lowest irradiance. It was always much longer than payback time, even under the lowest irradiance. Leaves were shed when their photosynthesis had reached very low values, in contrast to what was predicted by an optimality model. The species ranking for the different traits was stable across irradiance treatments. The two pioneer species always displayed the smallest CC, leaf life span, and payback time. All species displayed a similar large irradiance-elicited plasticity. |
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Address |
[Coste, S; Epron, D; Dreyer, E] INRA, UMR1137, Ctr INRA Nancy, F-54280 Champenoux, France, Email: dreyer@nancy.inra.fr |
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Oxford Univ Press |
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0022-0957 |
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WOS:000292838700021 |
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no |
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EcoFoG @ webmaster @ |
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331 |
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Author |
Masse, P.S.M.; Kenne, M.; Mony, R.; Dejean, A.; Tindo, M. |
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Title |
Initial behavior in colony fragments of an introduced population of the invasive ant Wasmannia auropunctata |
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Journal Article |
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Year |
2011 |
Publication |
Comptes Rendus Biologies |
Abbreviated Journal |
C. R. Biol. |
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Volume |
334 |
Issue |
7 |
Pages |
572-576 |
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Keywords |
Aggregation; Death feigning; Thanatosis; Worker transportation; Biological invasion; Little fire ant |
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Abstract |
We investigated in the laboratory the initial behavior of propagules of the invasive ant Wasmannia auropunctata in Cameroon where it has been introduced. Both workers and queens at first feigned death (thanatosis), and then the workers slowly moved around the experimental arena; the queens did the same about 10 seconds later. Each queen antennated selected workers that then aggregated together by grasping the hind leg of another ant with their mandibles. When encountering the queen again, the lead worker climbed up the queen's hind leg and onto her back, followed by some other individuals. The remaining workers followed the queen to a location in the experimental arena. When brood was present, the workers transferred it to this location. Orphaned workers did not aggregate, but gathered the brood together and took care of it. By permitting propagules to survive, these behaviors likely contribute to the success of W. auropunctata as an invader. (C) 2011 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved. |
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Address |
[Kenne, M; Mony, R; Tindo, M] Univ Douala, Fac Sci, Dept Biol Organismes Anim, Douala, Cameroon, Email: tindodouala@yahoo.com |
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Elsevier France-Editions Scientifiques Medicales Elsevier |
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1631-0691 |
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WOS:000293673300010 |
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no |
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EcoFoG @ webmaster @ |
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332 |
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Barantal, S.; Roy, J.; Fromin, N.; Schimann, H.; Hattenschwiler, S. |
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Title |
Long-term presence of tree species but not chemical diversity affect litter mixture effects on decomposition in a neotropical rainforest |
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Journal Article |
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Year |
2011 |
Publication |
Oecologia |
Abbreviated Journal |
Oecologia |
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Volume |
167 |
Issue |
1 |
Pages |
241-252 |
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Keywords |
Amazonian rainforest; Chemical diversity; Decomposition; Functional diversity indices; Litter traits |
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Abstract |
Plant litter diversity effects on decomposition rates are frequently reported, but with a strong bias towards temperate ecosystems. Altered decomposition and nutrient recycling with changing litter diversity may be particularly important in tree species-rich tropical rainforests on nutrient-poor soils. Using 28 different mixtures of leaf litter from 16 Amazonian rainforest tree species, we tested the hypothesis that litter mixture effects on decomposition increase with increasing functional litter diversity. Litter mixtures and all single litter species were exposed in the field for 9 months using custom-made microcosms with soil fauna access. In order to test the hypothesis that the long-term presence of tree species contributing to the litter mixtures increases mixture effects on decomposition, microcosms were installed in a plantation at sites including the respective tree species composition and in a nearby natural forest where these tree species are absent. We found that mixture decomposition deviated from predictions based on single species, with predominantly synergistic effects. Functional litter diversity, defined as either richness, evenness, or divergence based on a wide range of chemical traits, did not explain the observed litter mixture effects. However, synergistic effects in litter mixtures increased with the long-term presence of tree species contributing to these mixtures as the home field advantage hypothesis assumes. Our data suggest that complementarity effects on mixed litter decomposition may emerge through long-term interactions between aboveground and belowground biota. |
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Address |
[Barantal, S; Roy, J; Fromin, N; Hattenschwiler, S] CEFE CNRS, UMR 5175, F-34293 Montpellier 5, France, Email: sandra.barantal@cefe.cnrs.fr |
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Springer |
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0029-8549 |
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WOS:000293914000024 |
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no |
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EcoFoG @ webmaster @ |
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336 |
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Author |
Wagner, F.; Herault, B.; Stahl, C.; Bonal, D.; Rossi, V. |
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Title |
Modeling water availability for trees in tropical forests |
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Journal Article |
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Year |
2011 |
Publication |
Agricultural and Forest Meteorology |
Abbreviated Journal |
Agric. For. Meteorol. |
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Volume |
151 |
Issue |
9 |
Pages |
1202-1213 |
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Keywords |
Water balance model; Amazonian rainforest; Time domain reflectometer; Bayesian inference; Tree drought stress |
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Abstract |
Modeling soil water availability for tropical trees is a prerequisite to predicting the future impact of climate change on tropical forests. In this paper we develop a discrete-time deterministic water balance model adapted to tropical rainforest climates, and we validate it on a large dataset that includes micrometeorological and soil parameters along a topographic gradient in a lowland forest of French Guiana. The model computes daily water fluxes (rainfall interception, drainage, tree transpiration and soil plus understorey evapotranspiration) and soil water content using three input variables: daily precipitation, potential evapotranspiration and solar radiation. A novel statistical approach is employed that uses Time Domain Reflectometer (TDR) soil moisture data to estimate water content at permanent wilting point and at field capacity, and root distribution. Inaccuracy of the TDR probes and other sources of uncertainty are taken into account by model calibration through a Bayesian framework. Model daily output includes relative extractable water, REW, i.e. the daily available water standardized by potential available water. The model succeeds in capturing temporal variations in REW regardless of topographic context. The low Root Mean Square Error of Predictions suggests that the model captures the most important drivers of soil water dynamics, i.e. water refilling and root water extraction. Our model thus provides a useful tool to explore the response of tropical forests to climate scenarios of changing rainfall regime and intensity. (C) 2011 Elsevier B.V. All rights reserved. |
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Address |
[Wagner, F; Herault, B] Univ Antilles Guyane, UMR Ecol Forets Guyane, F-97387 Kourou, France, Email: fabien.wagner@ecofog.gf |
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Elsevier Science Bv |
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0168-1923 |
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WOS:000294032000005 |
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EcoFoG @ webmaster @ |
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337 |
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Author |
Barabe, D.; Lacroix, C.; Gibernau, M. |
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Title |
Floral development of Urospatha: merosity and phylogeny in the Lasioideae (Araceae) |
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Journal Article |
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Year |
2011 |
Publication |
Plant Systematics and Evolution |
Abbreviated Journal |
Plant Syst. Evol. |
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Volume |
296 |
Issue |
1-2 |
Pages |
41-50 |
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Keywords |
Inflorescence; Homeosis; Angiosperms; Systematic; Morphogenetic constraints |
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Abstract |
In this paper we study merosity in the genus Urospatha within the framework of a resolved phylogeny of the Araceae. We analyse how a transition from dimerous or tetramerous merosity to pentamerous or hexamerous merosity can occur developmentally in the Lasioideae. In Urospatha, initiation of floral primordia along the inflorescence is acropetal, while development of flowers is basipetal. This indicates the presence of two distinct phases in the development of the Urospatha inflorescence. The first phase corresponds to initiation of flowers and establishment of the phyllotactic pattern, and the second phase to differentiation of floral organs. Urospatha is characterized by the presence of trimerous, tetramerous, pentamerous and rarely hexamerous flowers. In all types of flowers, the stamens are closely associated and opposite to the tepals. Pentamerous flowers are formed by addition of a sector comprising a stamen and tepal. Likewise, in the case of hexamerous flowers, two sectors are added. In the Lasioideae, the increase in the number of tepals and stamens is linked with two developmental processes that have appeared independently in the subfamily: (1) addition of one or two stamen-petal sectors (Anaphyllopsis and Urospatha), and (2) independent increase in the number of tepals and stamens on whorls, more or less organized and inserted in alternate position (Dracontium). Tetramerous whorls as they occur in basal Lasioideae would be homologous to two dimerous whorls from an evolutionary point of view. |
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Address |
[Barabe, D; Gibernau, M] CNRS UMR Ecol Forets Guyane 8172, F-97387 Kourou, France, Email: denis.barabe@umontreal.ca |
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Springer Wien |
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0378-2697 |
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WOS:000294201300004 |
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no |
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Call Number |
EcoFoG @ webmaster @ |
Serial |
338 |
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Author |
Rey, O.; Loiseau, A.; Facon, B.; Foucaud, J.; Orivel, J.; Cornuet, J.M.; Robert, S.; Dobigny, G.; Delabie, J.H.C.; Mariano, C.D.F.; Estoup, A. |
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Title |
Meiotic Recombination Dramatically Decreased in Thelytokous Queens of the Little Fire Ant and Their Sexually Produced Workers |
Type |
Journal Article |
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Year |
2011 |
Publication |
Molecular Biology and Evolution |
Abbreviated Journal |
Mol. Biol. Evol. |
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Volume |
28 |
Issue |
9 |
Pages |
2591-2601 |
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Keywords |
parthenogenesis; thelytoky; recombination; inbreeding; biological invasion; Wasmannia auropunctata |
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Abstract |
The little fire ant, Wasmannia auropunctata, displays a peculiar breeding system polymorphism. Classical haplo-diploid sexual reproduction between reproductive individuals occurs in some populations, whereas, in others, queens and males reproduce clonally. Workers are produced sexually and are sterile in both clonal and sexual populations. The evolutionary fate of the clonal lineages depends strongly on the underlying mechanisms allowing reproductive individuals to transmit their genomes to subsequent generations. We used several queen-offspring data sets to estimate the rate of transition from heterozygosity to homozygosity associated with recombination events at 33 microsatellite loci in thelytokous parthenogenetic queen lineages and compared these rates with theoretical expectations under various parthenogenesis mechanisms. We then used sexually produced worker families to define linkage groups for these 33 loci and to compare meiotic recombination rates in sexual and parthenogenetic queens. Our results demonstrate that queens from clonal populations reproduce by automictic parthenogenesis with central fusion. These same parthenogenetic queens produce normally segregating meiotic oocytes for workers, which display much lower rates of recombination (by a factor of 45) than workers produced by sexual queens. These low recombination rates also concern the parthenogenetic production of queen offspring, as indicated by the very low rates of transition from heterozygosity to homozygosity observed (from 0% to 2.8%). We suggest that the combination of automixis with central fusion and a major decrease in recombination rates allows clonal queens to benefit from thelytoky while avoiding the potential inbreeding depression resulting from the loss of heterozygosity during automixis. In sterile workers, the strong decrease of recombination rates may also facilitate the conservation over time of some coadapted allelic interactions within chromosomes that might confer an adaptive advantage in habitats disturbed by human activity, where clonal populations of W. auropunctata are mostly found. |
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[Rey, O; Loiseau, A; Facon, B; Foucaud, J; Cornuet, JM; Robert, S; Dobigny, G] INRA, UMR Ctr Biol Gest Populat INRA IRD CIRAD Montpe, Montferrier Sur Lez, France, Email: olivier.rey@supagro.inra.fr |
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Oxford Univ Press |
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0737-4038 |
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WOS:000294552700019 |
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EcoFoG @ webmaster @ |
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339 |
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