| Records |
| Author |
Herault, B. |
| Title |
Reconciling niche and neutrality through the Emergent Group approach |
Type |
Journal Article |
| Year |
2007 |
Publication |
Perspectives in Plant Ecology Evolution and Systematics |
Abbreviated Journal |
Perspect. Plant Ecol. Evol. Syst. |
| Volume |
9 |
Issue |
2 |
Pages |
71-78 |
| Keywords |
Biodiversity; ecological equivalency; biological traits; neutral theory; niche differentiation; redundancy |
| Abstract |
Both niche and neutral theories have been suggested as potential frameworks for modelling biodiversity. Niche models assume that biological traits represent evolutionary adaptations and define individuals in terms of functional trade-offs. Neutral models assume that all individuals at a single trophic level are functionally equivalent on a per capita basis with respect to their birth, death, dispersal and speciation. The opinion of many researchers is that neutral and niche processes operate simultaneously to generate diversity without knowing how the unification of both models can be achieved. Recently, several theoretical papers have reported evidence on the evolutionary emergence of niche structures shaping the emergence of groups of similar species. In this way, an Emergent Group is defined as a set of species that have a similar functional niche owing to a convergent ecological strategy. Central to the Emergent Group concept are the assumptions of functional equivalence within and of functional divergence between Emergent Groups. Within an Emergent Group, species richness is subject to a zero-sum rule set by the balance between the rate of individual loss and of immigration. Between Emergent Groups, tradeoffs such as seed size/seedling competitivity, investment in reproductive system/investment in vegetative systems or competitive ability/predator invulnerability are cornerstones of the evolutionary divergence. Delineating Emergent Groups amounts to reaching a compromise between maximizing niche differentiation (i.e. maximizing differences in functional tradeoffs) between Emergent Groups and maximizing neutrality within Emergent Groups. Up to now, the Emergent Group concept has been mostly proposed by theoretical scientists but it should be tested by empirical ecologists. The way in which niche and neutral models could be combined provides a profitable opportunity for theoretical and empirical scientists to collaborate fruitfully. (c) 2007 Rubel Foundation, ETH Zurich. Published by Elsevier GmbH. All rights reserved. |
| Address |
[Herault, Bruno] Univ Antilles Guyane, UMR Ecol Forets Guyane, F-97379 Kourou, France, Email: Bruno.Herault@cirad.fr |
| Corporate Author |
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Thesis |
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| Publisher |
ELSEVIER GMBH, URBAN & FISCHER VERLAG |
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Editor |
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Summary Language |
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Original Title |
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Series Editor  |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
1433-8319 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
ISI:000251685100002 |
Approved |
no |
| Call Number |
EcoFoG @ eric.marcon @ |
Serial |
147 |
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| Author |
Jaouen, G.; Almeras, T.; Coutand, C.; Fournier, M. |
| Title |
How to determine sapling buckling risk with only a few measurements |
Type |
Journal Article |
| Year |
2007 |
Publication |
American Journal of Botany |
Abbreviated Journal |
Am. J. Bot. |
| Volume |
94 |
Issue |
10 |
Pages |
1583-1593 |
| Keywords |
biomechanics; critical buckling height; French Guiana; risk factor; sapling; stem form; tropical rain forest; trunk volume |
| Abstract |
Tree buckling risk (actual height/critical buckling height) is an important biomechanical trait of plant growth strategies, and one that contributes to species coexistence. To estimate the diversity of this trait among wide samples, a method that minimizes damage to the plants is necessary. On the basis of the rarely used, complete version of Greenhill's model (1881, Proceedings of the Cambridge Philosophical Society 4(2): 65-73), we precisely measured all the necessary parameters on a sample of 236 saplings of 16 species. Then, using sensitivity (variance) analysis, regressions between successive models for risk factors and species ranks and the use of these models on samples of self- and nonself-supporting saplings, we tested different degrees of simplification up to the most simple and widely used formula that assumes that the tree is a cylindrical homogeneous pole. The size factor had the greatest effect on buckling risk, followed by the form factor and the modulus of elasticity of the wood. Therefore, estimates of buckling risk must consider not only the wood properties but especially the form factor. Finally, we proposed a simple but accurate method of assessing tree buckling risk that is applicable to a wide range of samples and that requires mostly nondestructive measurements. |
| Address |
INRA, UMR Ecol Forets Guyane, Kourou 97379, French Guiana, Email: jaouen-g@kourou.cirad.fr |
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Thesis |
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| Publisher |
BOTANICAL SOC AMER INC |
Place of Publication |
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Original Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0002-9122 |
ISBN |
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Medium |
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Expedition |
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Conference |
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| Notes |
ISI:000251466600001 |
Approved |
no |
| Call Number |
EcoFoG @ eric.marcon @ |
Serial |
148 |
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| Author |
Rockwell, C.A.; Kainer, K.A.; Staudhammer, C.L.; Baraloto, C. |
| Title |
Future crop tree damage in a certified community forest in southwestern Amazonia |
Type |
Journal Article |
| Year |
2007 |
Publication |
Forest Ecology and Management |
Abbreviated Journal |
For. Ecol. Manage. |
| Volume |
242 |
Issue |
2-3 |
Pages |
108-118 |
| Keywords |
bamboo; community forest management; forest certification; Guadua; liana; marking; reduced-impact logging; RIL; timber management; tropical forest |
| Abstract |
Field studies in Acre, Brazil assessed logging impacts of a certified community timber management project. The main objectives of the study were: (1) to determine if damage incidence to future crop trees (FCTs; >= 20 cm diameter at breast height (dbh)) differs between (a) forest with and without bamboo (Guadua spp.), and (b) trees with and without lianas; (2) to what extent harvesting can be conducted more intensely (m(3)ha(-1)), without incurring greater FCT damage; and (3) to what extent marking diminishes FCT damage. Full inventories of FCTs of 50 commercial species complexes were conducted before and after logging in 50 m-radius zones of impact around each designated harvest tree in three 10 ha (200 m x 500 m) logging blocks. We also mapped all forested areas potentially influenced by logging, including skid trails, log landings and felling gaps, throughout the 30 ha logged. More than 28% of the forest area was disturbed by logging, with 12.1% in skid trails and 16.8% in gap clearings, indicating that the forest gap mosaic can be significantly altered even when reduced-impact logging guidelines are followed. Overall, 15% of FCTs inventoried were damaged. Damage rates were not significantly reduced by marking treatment, location in bamboo-dominated forest, or liana load on FCT damage. Harvest intensity did not influence the probability of FCT damage. For future studies, it would be prudent to address impacts of timber extraction on other livelihood activities, such as non-timber forest product collection, particularly in such regions as the Brazilian Amazon, where many communities are attempting to integrate a suite of income-generating activities. (C) 2007 Elsevier B.V. All rights reserved. |
| Address |
Univ Florida, Sch Forest Resources & Conservat, Gainesville, FL 32611 USA, Email: crockwel@ufl.edu |
| Corporate Author |
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Thesis |
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| Publisher |
ELSEVIER SCIENCE BV |
Place of Publication |
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Editor |
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Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0378-1127 |
ISBN |
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Medium |
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Conference |
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| Notes |
ISI:000246268100003 |
Approved |
no |
| Call Number |
EcoFoG @ eric.marcon @ |
Serial |
217 |
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| Author |
Yamamoto, H.; Almeras, T. |
| Title |
A mathematical verification of the reinforced-matrix hypothesis using the Mori-Tanaka theory |
Type |
Journal Article |
| Year |
2007 |
Publication |
Journal of Wood Science |
Abbreviated Journal |
J. Wood Sci. |
| Volume |
53 |
Issue |
6 |
Pages |
505-509 |
| Keywords |
Engineering |
| Abstract |
This article presents a theoretical verification of the reinforced-matrix hypothesis derived from tensor equations, σ W = σ f + σ m and ε W = ε f = ε m (Wood Sci Technol 32:171–182, 1998; Wood Sci Technol 33:311–325, 1999; J Biomech Eng 124:432–440, 2002), using classical Mori-Tanaka theory on the micromechanics of fiber-reinforced materials (Acta Metall 21:571–574, 1973; Micromechanics — dislcation and inclusions (in Japanese), pp 141–147, 1976). The Mori-Tanaka theory was applied to a small fragment of the cell wall undergoing changes in its physical state, such as those arising from sorption of moisture, maturation of wall components, or action of an external force, to obtain ⟨σ A⟩D = ϕ·⟨σ F⟩I + (1−ϕ)·⟨σ M⟩D−I. When the constitutive equation of each constituent material was applied to the equation ⟨σ A⟩D = ϕ·⟨σ F⟩I + (1−ϕ)·⟨σ M⟩D−I, the equations σ W = σ f + σ m and ε W = ε f = ε m were derived to lend support to the concept that two main phases, the reinforcing cellulose microfibril and the lignin-hemicellulose matrix, coexist in the same domain. The constitutive equations for the cell wall fragment were obtained without recourse to additional parameters such as Eshelby’s tensor S and Hill’s averaged concentration tensors AF and AM. In our previous articles, the coexistence of two main phases and σ W = σ f + σ m and ε W = ε f =ε m had been taken as our starting point to formulate the behavior of wood fiber with multilayered cell walls. The present article provides a rational explanation for both concepts. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
Springer Japan |
Place of Publication |
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Editor |
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Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
1435-0211 |
ISBN |
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| Notes |
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Approved |
no |
| Call Number |
EcoFoG @ eric.marcon @ |
Serial |
215 |
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| Author |
Luyssaert, S.; Inglima, I.; Jung, M.; Richardson, A.D.; Reichsteins, M.; Papale, D.; Piao, S.L.; Schulzes, E.D.; Wingate, L.; Matteucci, G.; Aragao, L.; Aubinet, M.; Beers, C.; Bernhoffer, C.; Black, K.G.; Bonal, D.; Bonnefond, J.M.; Chambers, J.; Ciais, P.; Cook, B.; Davis, K.J.; Dolman, A.J.; Gielen, B.; Goulden, M.; Grace, J.; Granier, A.; Grelle, A.; Griffis, T.; Grunwald, T.; Guidolotti, G.; Hanson, P.J.; Harding, R.; Hollinger, D.Y.; Hutyra, L.R.; Kolar, P.; Kruijt, B.; Kutsch, W.; Lagergren, F.; Laurila, T.; Law, B.E.; Le Maire, G.; Lindroth, A.; Loustau, D.; Malhi, Y.; Mateus, J.; Migliavacca, M.; Misson, L.; Montagnani, L.; Moncrieff, J.; Moors, E.; Munger, J.W.; Nikinmaa, E.; Ollinger, S.V.; Pita, G.; Rebmann, C.; Roupsard, O.; Saigusa, N.; Sanz, M.J.; Seufert, G.; Sierra, C.; Smith, M.L.; Tang, J.; Valentini, R.; Vesala, T.; Janssens, I.A. |
| Title |
CO2 balance of boreal, temperate, and tropical forests derived from a global database |
Type |
Journal Article |
| Year |
2007 |
Publication |
Global Change Biology |
Abbreviated Journal |
Glob. Change Biol. |
| Volume |
13 |
Issue |
12 |
Pages |
2509-2537 |
| Keywords |
carbon cycle; CO2; forest ecosystems; global database; gross primary productivity; net ecosystem productivity; net primary productivity |
| Abstract |
Terrestrial ecosystems sequester 2.1 Pg of atmospheric carbon annually. A large amount of the terrestrial sink is realized by forests. However, considerable uncertainties remain regarding the fate of this carbon over both short and long timescales. Relevant data to address these uncertainties are being collected at many sites around the world, but syntheses of these data are still sparse. To facilitate future synthesis activities, we have assembled a comprehensive global database for forest ecosystems, which includes carbon budget variables (fluxes and stocks), ecosystem traits (e.g. leaf area index, age), as well as ancillary site information such as management regime, climate, and soil characteristics. This publicly available database can be used to quantify global, regional or biome-specific carbon budgets; to re-examine established relationships; to test emerging hypotheses about ecosystem functioning [e.g. a constant net ecosystem production (NEP) to gross primary production (GPP) ratio]; and as benchmarks for model evaluations. In this paper, we present the first analysis of this database. We discuss the climatic influences on GPP, net primary production (NPP) and NEP and present the CO2 balances for boreal, temperate, and tropical forest biomes based on micrometeorological, ecophysiological, and biometric flux and inventory estimates. Globally, GPP of forests benefited from higher temperatures and precipitation whereas NPP saturated above either a threshold of 1500 mm precipitation or a mean annual temperature of 10 degrees C. The global pattern in NEP was insensitive to climate and is hypothesized to be mainly determined by nonclimatic conditions such as successional stage, management, site history, and site disturbance. In all biomes, closing the CO2 balance required the introduction of substantial biome-specific closure terms. Nonclosure was taken as an indication that respiratory processes, advection, and non-CO2 carbon fluxes are not presently being adequately accounted for. |
| Address |
Univ Antwerp, Dept Biol, B-2610 Antwerp, Belgium, Email: Sebastiaan.Luyssaert@ua.ac.be |
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Thesis |
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| Publisher |
BLACKWELL PUBLISHING |
Place of Publication |
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Summary Language |
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Series Issue |
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Edition |
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| ISSN |
1354-1013 |
ISBN |
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Conference |
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| Notes |
ISI:000251049000004 |
Approved |
no |
| Call Number |
EcoFoG @ eric.marcon @ |
Serial |
151 |
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| Author |
Almeras, T.; Gril, J. |
| Title |
Mechanical analysis of the strains generated by water tension in plant stems. Part 1: stress transmission from the water to the cell walls |
Type |
Journal Article |
| Year |
2007 |
Publication |
Tree Physiology |
Abbreviated Journal |
Tree Physiol. |
| Volume |
27 |
Issue |
11 |
Pages |
1505-1516 |
| Keywords |
biomechanics; cell mechanics; diurnal strains; mechanical model; multilayer cylinder; stress transtnissionjactor |
| Abstract |
Plant tissues shrink and swell in response to changes in water pressure. These strains can be easily measured, e.g., at the surface of tree stems, to obtain indirect information about plant water status and other physiological parameters. We developed a mechanical model to clarify how water pressure is transmitted to cell walls and causes shrinkage of plant tissues, particularly in the case of thick-walled cells such as wood fibers. Our analysis shows that the stress inside the fiber cell walls is lower than the water tension. The difference is accounted for by a stress transmission factor that depends on two main effects. The first effect is the dilution of the stress through the cell wall, because water acts at the lumen border and is transmitted to the cuter border of the cell, which has a larger circumference. The second effect is the partial conversion of radial stress into tangential stress. Both effects are quantified as functions of parameters of the cell wall structure and its mechanical properties. |
| Address |
INRA, UMR Ecofog, F-97379 Kourou, French Guiana, France, Email: t_almeras@hotmail.com |
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Thesis |
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| Publisher |
HERON PUBLISHING |
Place of Publication |
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Editor |
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Summary Language |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0829-318X |
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| Notes |
ISI:000250847000001 |
Approved |
no |
| Call Number |
EcoFoG @ eric.marcon @ |
Serial |
152 |
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| Author |
LaPierre, L.; Hespenheide, H.; Dejean, A. |
| Title |
Wasps robbing food from ants: a frequent behavior? |
Type |
Journal Article |
| Year |
2007 |
Publication |
Naturwissenschaften |
Abbreviated Journal |
Naturwissenschaften |
| Volume |
94 |
Issue |
12 |
Pages |
997-1001 |
| Keywords |
cleptobiosis; social wasps; charterginus; polybioides; plant-ants |
| Abstract |
Food robbing, or cleptobiosis, has been well documented throughout the animal kingdom. For insects, intrafamilial food robbing is known among ants, but social wasps (Vespidae; Polistinae) taking food from ants has, to the best of our knowledge, never been reported. In this paper, we present two cases involving social wasps robbing food from ants associated with myrmecophytes. (1) Polybioides tabida F. (Ropalidiini) rob pieces of prey from Tetraponera aethiops Smith (Formicidae; Pseudomyrmecinae) specifically associated with Barteria fistulosa Mast. (Passifloraceae). (2) Charterginus spp. (Epiponini) rob food bodies from myrmecophytic Cecropia (Cecropiaceae) exploited by their Azteca mutualists (Formicidae; Dolichoderinae) or by opportunistic ants (that also attack cleptobiotic wasps). We note here that wasps gather food bodies (1) when ants are not yet active; (2) when ants are active, but avoiding any contact with them by flying off when attacked; and (3) through the coordinated efforts of two to five wasps, wherein one of them prevents the ants from leaving their nest, while the other wasps freely gather the food bodies. We suggest that these interactions are more common than previously thought. |
| Address |
CNRS Guyane, UPS2561, UMR5174, F-97300 Cayenne, France, Email: llapierre@lowercolumbia.edu |
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SPRINGER |
Place of Publication |
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Summary Language |
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Original Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0028-1042 |
ISBN |
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| Notes |
ISI:000250980800006 |
Approved |
no |
| Call Number |
EcoFoG @ eric.marcon @ |
Serial |
153 |
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| Author |
Schimann, H.; Joffre, R.; Roggy, J.C.; Lensi, R.; Domenach, A.M. |
| Title |
Evaluation of the recovery of microbial functions during soil restoration using near-infrared spectroscopy |
Type |
Journal Article |
| Year |
2007 |
Publication |
Applied Soil Ecology |
Abbreviated Journal |
Appl. Soil Ecol. |
| Volume |
37 |
Issue |
3 |
Pages |
223-232 |
| Keywords |
NIRS; microbial activities; respiration; denitrification; carbon; nitrogen; soil functioning; restoration |
| Abstract |
Microbial-based indicators, such as C and N contents or microbial functions involved in C and N cycles, are currently used to describe the status of soils in disturbed areas. Microbial functions are more accurate indicators but their measurement for studies at the ecosystem level remains problematical because of the huge spatial variability of these processes and, consequently, of the large number of soil samples which must be analyzed. Our goal was to test the capacity of near-infrared reflectance spectroscopy (NIRS) to predict respiration and denitrification but also carbon and nitrogen contents of soils submitted to various procedures of restoration. To achieve this objective, we took advantage of an experiment conducted on a reforestation system established after open-cast gold mining in French Guiana. In this experimental station, plantations of various ages and various soil textures were at our disposal. Our results showed that both plantations and soil texture had a strong impact on the recovery of soil functioning: carbon and nitrogen contents, respiration and denitrification increased with age of plantation and clay content. Calibrations were performed between spectral data and microbial-based indicators using partial least squares regression (PLS). The results showed that C and N contents were accurately predicted. Microbial functions were less precisely predicted with results more accurate on clayey soils than on sandy soils. In clayey soils, perturbed or restored soils and the year of plantation were discriminated very efficiently through principal component analyses of spectral signatures (over 80% of variance explained on the first two axes). Near-infrared spectroscopy may thus be extended to the prediction of functional soil parameters, but the capacity of this method must be strengthened by expending the databases with other soils in other contexts. The possibility of using NIRS provides many opportunities for understanding both the temporal dynamics and the spatial variability of the recovery of key microbial functions during soil restoration. (c) 2007 Elsevier B.V. All rights reserved. |
| Address |
UMR EcoFoG, Kourou 97387, French Guiana, Email: heidy.schimann@cirad.fr |
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Thesis |
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| Publisher |
ELSEVIER SCIENCE BV |
Place of Publication |
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Summary Language |
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Edition |
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| ISSN |
0929-1393 |
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| Notes |
ISI:000250668000006 |
Approved |
no |
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EcoFoG @ eric.marcon @ |
Serial |
154 |
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| Author |
Fang, C.H.; Clair, B.; Gril, J.; Almeras, T. |
| Title |
Transverse shrinkage in G-fibers as a function of cell wall layering and growth strain |
Type |
Journal Article |
| Year |
2007 |
Publication |
Wood Science and Technology |
Abbreviated Journal |
Wood Sci. Technol. |
| Volume |
41 |
Issue |
8 |
Pages |
659-671 |
| Keywords |
|
| Abstract |
Transverse drying shrinkage was measured at microscopic and mesoscopic levels in poplar wood characterised by an increasing growth strain (GS), from normal to tension wood. Results show that: (a) the drying shrinkage, measured as a relative thickness decrease, was significantly higher for G-layer (GL) than for the other layers (OL), GL shrinkage was not significantly correlated with GS, and OL shrinkage was negatively correlated with GS. (b) In gelatinous fibre (G-fibre), lumen size increased during drying and this increase was positively related with GS, but in normal wood fibre, lumen size decreased during drying. These findings suggest that GL shrank outwards (i.e., its internal perimeter increases), so that its shrinkage weakly affected the total cell shrinkage and the mesoscopic shrinkage was controlled by the OL shrinkage which shrank inwards (i.e., its external perimeter decreases). (c) Measurements done on 7 x 7 mm(2) thin sections evidenced a negative correlation between transverse shrinkage and GS, significant in T direction but weak in R direction. These observations at both levels allow to discuss the contribution of GL to the mesoscopic shrinkage of tension wood. |
| Address |
Univ Montpellier 2, Lab Mech & Gene Civil, F-34095 Montpellier, France, Email: fang1979@gmail.com |
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SPRINGER |
Place of Publication |
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Summary Language |
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Original Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0043-7719 |
ISBN |
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| Notes |
ISI:000250381500003 |
Approved |
no |
| Call Number |
EcoFoG @ eric.marcon @ |
Serial |
155 |
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| Author |
Christensen-Dalsgaard, K.K.; Fournier, M.; Ennos, A.R.; Barfod, A.S. |
| Title |
Changes in vessel anatomy in response to mechanical loading in six species of tropical trees |
Type |
Journal Article |
| Year |
2007 |
Publication |
New Phytologist |
Abbreviated Journal |
New Phytol. |
| Volume |
176 |
Issue |
3 |
Pages |
610-622 |
| Keywords |
hydraulic architecture; hydraulic-mechanical trade-off; mechanical adaptation; rooting morphology; tropical trees; vascular anatomy |
| Abstract |
It is well known that trees adapt their supportive tissues to changes in loading conditions, yet little is known about how the vascular anatomy is modified in this process. We investigated this by comparing more and less mechanically loaded sections in six species of tropical trees with two different rooting morphologies. We measured the strain, vessel size, frequency and area fraction and from this calculated the specific conductivity, then measured the conductivity, modulus of elasticity and yield stress. The smallest vessels and the lowest vessel frequency were found in the parts of the trees subjected to the greatest stresses or strains. The specific conductivity varied up to two orders of magnitude between mechanically loaded and mechanically unimportant parts of the root system. A trade-off between conductivity and stiffness or strength was revealed, which suggests that anatomical alterations occur in response to mechanical strain. By contrast, between-tree comparisons showed that average anatomical features for the whole tree seemed more closely related to their ecological strategy. |
| Address |
Univ Manchester, Fac Life Sci, Manchester M60 1QD, Lancs, England, Email: karen@cd-mail.dk |
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| Publisher |
BLACKWELL PUBLISHING |
Place of Publication |
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Summary Language |
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Original Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0028-646X |
ISBN |
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Expedition |
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Conference |
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| Notes |
ISI:000250275000013 |
Approved |
no |
| Call Number |
EcoFoG @ eric.marcon @ |
Serial |
156 |
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