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Author |
Baraloto, C.; Bonal, D.; Goldberg, D.E. |
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Title |
Differential seedling growth response to soil resource availability among nine neotropical tree species |
Type |
Journal Article |
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Year  |
2006 |
Publication |
Journal of Tropical Ecology |
Abbreviated Journal |
J. Trop. Ecol. |
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Volume |
22 |
Issue |
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Pages |
487-497 |
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Keywords |
biomass allocation; Dicorynia; drought stress; Eperua; French Guiana; Goupia; Jacaranda; plasticity; Qualea; Recordorylon; relative growth rate; Sextonia; soil phosphorus; specific leaf area; Virola |
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Abstract |
Although the potential contribution to tropical tree species coexistence of niche differentiation along light gradients has received much attention, the degree to which species perform differentially along soil resource gradients remains unclear. To examine differential growth response to soil resources, we grew seedlings of nine tropical tree species at 6.0% of full sun for 12 mo in a factorial design of two soil types (clay and white sand), two phosphate fertilization treatments (control and addition of 100 mg P kg(-1)) and two watering treatments (field capacity and water limitation to one-third field capacity). Species differed markedly in biomass growth rate, but this hierarchy was almost completely conserved across all eight treatments. All species grew more slowly in sand than clay soils. and no species grew faster with phosphate additions. Only Eperua grandiflora and E. falcata showed significant growth increases in the absence of water limitation. Faster-growing species were characterized by high specific leaf area, high leaf allocation and high net assimilation rate but not lower root allocation. Slower-growing species exhibited greater plasticity in net assimilation rate. suggesting that tolerance of edaphic stress in these species is related more to stomatal control than to whole-plant carbon allocation. Although relative growth rate for biomass was correlated with both its physiological and morphological components. interspecific differences were best explained by differences in net assimilation rate across six of the eight treatments. A suite of traits including high assimilation and high specific leaf area maintains rapid growth rate of faster-growing species across a wide gradient of soil resources, but the lack of plasticity they exhibit may compromise their survival in the poorest soil environments. |
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Address |
Univ Michigan, Dept Ecol & Evolutionary Biol, Ann Arbor, MI 48109 USA, Email: baraloto.c@kourou.cirad.fr |
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CAMBRIDGE UNIV PRESS |
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0266-4674 |
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ISI:000239975200001 |
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Call Number |
EcoFoG @ eric.marcon @ |
Serial |
178 |
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Author |
Epron, D.; Bosc, A.; Bonal, D.; Freycon, V. |
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Title |
Spatial variation of soil respiration across a topographic gradient in a tropical rain forest in French Guiana |
Type |
Journal Article |
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Year |
2006 |
Publication |
Journal of Tropical Ecology |
Abbreviated Journal |
J. Trop. Ecol. |
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Volume |
22 |
Issue |
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Pages |
565-574 |
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Keywords |
acrisol; carbon balance; carbon flux; gleysol; root biomass |
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Abstract |
The objective of this study was to analyse the factors explaining spatial variation in soil respiration over topographic transects in a tropical rain forest of French Guiana. The soil of 30 plots along six transects was characterized. The appearance of the 'dry to the touch' character at a depth of less than 1.2 m was used to discriminate soils exhibiting vertical drainage from soils exhibiting superficial lateral drainage and along with colour and texture, to define five classes from well-drained to strongly hydromorphic soils. Spatial variation in soil respiration was closely related to topographic position and soil type. Increasing soil water content and bulk density and decreasing root biomass and soil carbon content explained most of the decrease in soil respiration from the plateaux (vertically drained hypoferralic acrisol) to the bottomlands (haplic gleysol). These results will help to stratify further field experiments and to identify the underlying determinants of spatial variation in soil respiration to develop mechanistic models of soil respiration. |
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Address |
Univ Nancy 1, UMR 1137, INRA, UHP Ecol & Ecophysiol Forestieres,Fac Sci, F-54506 Vandoeuvre Les Nancy, France, Email: Daniel.Epron@scbiol.uhp-nancy.fr |
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CAMBRIDGE UNIV PRESS |
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0266-4674 |
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ISI:000239975200008 |
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Call Number |
EcoFoG @ eric.marcon @ |
Serial |
179 |
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Author |
Degen, B.; Blanc, L.; Caron, H.; Maggia, L.; Kremer, A.; Gourlet-Fleury, S. |
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Title |
Impact of selective logging on genetic composition and demographic structure of four tropical tree species |
Type |
Journal Article |
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Year |
2006 |
Publication |
Biological Conservation |
Abbreviated Journal |
Biol. Conserv. |
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Volume |
131 |
Issue |
3 |
Pages |
386-401 |
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Keywords |
demography; genetic diversity; logging; phenology; pollen and seed dispersal; simulation; trees; tropics |
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Abstract |
Over-exploitation and fragmentation are serious problems for tropical forests. Most sustainable forest management practices avoid clear-cuts and apply selective logging systems focused on a few commercial species. We applied a simulation model to estimate the impact of such selective logging scenarios on the genetic diversity and demography of four tropical tree species from French Guiana. The simulations used data on genetic and demographic composition, growth, phenology and pollen and seed dispersal obtained for Dicorynia guianensis, Sextonia rubra, Symphonia globulifera and Vouacapoua americana at the experimental site in Paracou. Whereas Symphonia globulifera serves as a model for a species with low logging pressure, the other three species represent the most exploited tree species in French Guiana. In simulations with moderate logging, typical for French Guiana, with large cutting diameter (> 60 cm diameter) and long cutting cycles (65 years), the two species V. americana and Sextonia rubra were not able to recover their initial stock at the end of the rotation period, with a large decrease in the number of individuals and in basal area. Under a more intensive logging system (cutting diameter > 45 cm diameter, cutting cycles of 30 years) that is common practice in the Brazilian Amazon, only Symphonia globulifera showed no negative impact. Generally, the differences between the genetic parameters in the control scenarios without logging and the logging scenarios were surprisingly small. The main reasons for this were the overlapping of generations and the effective dispersal ability of gene vectors in all species, which guarantee relative homogeneity of the genetic structure in different age classes. Nevertheless, decreasing the population size by logging reduced the number of genotypes and caused higher genetic distances between the original population and the population at the end of the logging cycles. Sensitivity analysis showed that genetic changes in the logging scenarios were principally determined by the growth, densities and cutting diameter of each species, and only to a very small extent by the reproductive system including factors such as pollen and seed dispersal and flowering phenology. (c) 2006 Elsevier Ltd. All rights reserved. |
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Address |
BFH, Inst Forstgenet & Forstpflanzenzuchtung, D-22927 Grosshansdorf, Germany, Email: b.degen@holz.uni-hamburg.de |
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ELSEVIER SCI LTD |
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ISSN |
0006-3207 |
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Notes |
ISI:000239139400004 |
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no |
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Call Number |
EcoFoG @ eric.marcon @ |
Serial |
180 |
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Author |
Maron, P.A.; Schimann, H.; Ranjard, L.; Brothier, E.; Domenach, A.M.; Lensi, R.; Nazaret, S. |
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Title |
Evaluation of quantitative and qualitative recovery of bacterial communities from different soil types by density gradient centrifugation |
Type |
Journal Article |
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Year |
2006 |
Publication |
European Journal of Soil Biology |
Abbreviated Journal |
Eur. J. Soil Biol. |
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Volume |
42 |
Issue |
2 |
Pages |
65-73 |
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Keywords |
bacterial community; soil; density gradient; DNA fingerprint |
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Abstract |
Extracting and purifying a representative fraction of bacteria from soil is necessary for the application of many techniques of microbial ecology. Here the influence of different soil types on the quantitative and qualitative recovery of bacteria by soil grinding and Nycodenz density gradient centrifugation was investigated. Three soils presenting contrasted physicochemical characteristics were used for this study. For each soil, the total (AODC: acridine orange direct count) and culturable (cfa: colony-forming units) bacterial densities were measured in three distinct fractions: (i) the primary soil, (ii) the soil pellet (soil remaining after centrifugation), and (iii) the extracted cells. The automated-ribosomal intergenic spacer analysis (A-RISA) was used to characterize the community structure directly from the DNA extracted from each fraction. The physicochemical characteristics of soils were found to influence both the efficiency of bacterial cell recovery and the representativeness of the extracted cells in term of community structures between the different fractions. Surprisingly, the most representative extracted cells were obtained from the soil exhibiting the lowest efficiency of cell recovery. Our results demonstrated that quantitative and qualitative cell recovery using Nycodenz density gradient centrifugation are not necessarily related and could be differentially biased according to soil type. (c) 2006 Elsevier SAS. All rights reserved. |
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Address |
Univ Lyon 1, CNRS, UMR 5557, Ctr Microbial Ecol, F-69622 Villeurbanne, France, Email: nazaret@biomserv.univ-lyon1.fr |
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ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER |
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ISSN |
1164-5563 |
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Notes |
ISI:000238534500001 |
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no |
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Call Number |
EcoFoG @ eric.marcon @ |
Serial |
181 |
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Author |
Hardy, O.J.; Maggia, L.; Bandou, E.; Breyne, P.; Caron, H.; Chevallier, M.H.; Doligez, A.; Dutech, C.; Kremer, A.; Latouche-Halle, C.; Troispoux, V.; Veron, V.; Degen, B. |
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Title |
Fine-scale genetic structure and gene dispersal inferences in 10 Neotropical tree species |
Type |
Journal Article |
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Year |
2006 |
Publication |
Molecular Ecology |
Abbreviated Journal |
Mol. Ecol. |
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Volume |
15 |
Issue |
2 |
Pages |
559-571 |
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Keywords |
French Guiana; gene dispersal; seed dispersal; spatial genetic structure; tropical trees |
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Abstract |
The extent of gene dispersal is a fundamental factor of the population and evolutionary dynamics of tropical tree species, but directly monitoring seed and pollen movement is a difficult task. However, indirect estimates of historical gene dispersal can be obtained from the fine-scale spatial genetic structure of populations at drift-dispersal equilibrium. Using an approach that is based on the slope of the regression of pairwise kinship coefficients on spatial distance and estimates of the effective population density, we compare indirect gene dispersal estimates of sympatric populations of 10 tropical tree species. We re-analysed 26 data sets consisting of mapped allozyme, SSR (simple sequence repeat), RAPD (random amplified polymorphic DNA) or AFLP (amplified fragment length polymorphism) genotypes from two rainforest sites in French Guiana. Gene dispersal estimates were obtained for at least one marker in each species, although the estimation procedure failed under insufficient marker polymorphism, limited sample size, or inappropriate sampling area. Estimates generally suffered low precision and were affected by assumptions regarding the effective population density. Averaging estimates over data sets, the extent of gene dispersal ranged from 150 m to 1200 m according to species. Smaller gene dispersal estimates were obtained in species with heavy diaspores, which are presumably not well dispersed, and in populations with high local adult density. We suggest that limited seed dispersal could indirectly limit effective pollen dispersal by creating higher local tree densities, thereby increasing the positive correlation between pollen and seed dispersal distances. We discuss the potential and limitations of our indirect estimation procedure and suggest guidelines for future studies. |
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Address |
Univ Libre Bruxelles, Serv Ecoethol Evolut, B-1050 Brussels, Belgium, Email: ohardy@ulb.ac.be |
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Publisher |
BLACKWELL PUBLISHING |
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ISSN |
0962-1083 |
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Notes |
ISI:000235045500021 |
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no |
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Call Number |
EcoFoG @ eric.marcon @ |
Serial |
183 |
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Author |
Almeras, T.; Yoshida, M.; Okuyama, T. |
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Title |
The generation of longitudinal maturation stress in wood is not dependent on diurnal changes in diameter of trunk |
Type |
Journal Article |
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Year |
2006 |
Publication |
Journal of Wood Science |
Abbreviated Journal |
J. Wood Sci. |
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Volume |
52 |
Issue |
5 |
Pages |
452-455 |
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Keywords |
maturation stress; growth stress; cell-wall maturation; continuous lighting; diurnal strains |
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Abstract |
A hypothetical mechanism for the generation of maturation stress in wood was tested experimentally. The hypothesis was that the maturation stress could partly originate in a physical mechanism related to daily changes in water pressure and associated diurnal strains. The matrix of lignin and hemicellulose, deposited in the cell wall during the night, would be put in compression by the effect of water tension during the next day. The cellulose framework, crystallizing during the day, would be put in tension by the decrease in tension at night and subsequent cell-wall swelling. This was tested on young saplings of sugi and beech. Half of the saplings were submitted to continuous lighting, which canceled diurnal strains. Saplings were tilted 40 degrees, and their uprighting movement was measured. The uprighting movement is directly due to the production of reaction wood and the concomitant development of large longitudinal maturation stress. It occurred in the continuously lighted plants at least as much as in control plants. We conclude that the generation of longitudinal maturation stress in tension or compression wood is not directly related to variations in water pressure and diurnal strains. |
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Address |
Nagoya Univ, Grad Sch Bioagr Sci, Lab Biomat Phys, Chikusa Ku, Nagoya, Aichi 4648601, Japan, Email: t_almeras@hotmail.com |
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Publisher |
SPRINGER TOKYO |
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ISSN |
1435-0211 |
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Notes |
ISI:000241010600012 |
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no |
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Call Number |
EcoFoG @ eric.marcon @ |
Serial |
222 |
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Author |
Clair, B.; Almeras, T.; Sugiyama, J. |
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Title |
Compression stress in opposite wood of angiosperms: observations in chestnut, mani and poplar |
Type |
Journal Article |
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Year |
2006 |
Publication |
Annals of Forest Science |
Abbreviated Journal |
Ann. For. Sci. |
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Volume |
63 |
Issue |
5 |
Pages |
507-510 |
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Keywords |
reaction wood; compression wood; tension wood; opposite wood; plant biomechanics; growth stresses; microfibrils angle |
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Abstract |
In order to face environmental constraints, trees are able to re-orient their axes by controlling the stress level in the newly formed wood layers. Angiosperms and gymnosperms evolved into two distinct mechanisms: the former produce a wood with large tension pre-stress on the upper side of the tilted axis, while the latter produce a wood with large compression pre-stress on the lower side. In both cases, the difference between this stress level and that of the opposite side, in light tension, generates the bending of the axis. However, light values of compression were sometimes measured in the opposite side of angiosperms. By analysing old data on chestnut and mani and new data on poplar, this study shows that these values were not measurement artefacts. This reveals that generating light compression stress in opposite wood contributes to improve the performance of the re-orientation mechanism. |
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Address |
Kyoto Univ, Res Inst Sustainable Humanosphere, Lab Biomass Morphogenesis & Informat, Uji, Kyoto 6110011, Japan, Email: clair@lmgc.univ-montp2.fr |
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Publisher |
EDP SCIENCES S A |
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ISSN |
1286-4560 |
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Notes |
ISI:000240514800008 |
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no |
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Call Number |
EcoFoG @ eric.marcon @ |
Serial |
223 |
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Author |
Clair, B.; Almeras, T.; Yamamoto, H.; Okuyama, T.; Sugiyama, J. |
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Title |
Mechanical behavior of cellulose microfibrils in tension wood, in relation with maturation stress generation |
Type |
Journal Article |
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Year |
2006 |
Publication |
Biophysical Journal |
Abbreviated Journal |
Biophys. J. |
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Volume |
91 |
Issue |
3 |
Pages |
1128-1135 |
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Keywords |
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Abstract |
A change in cellulose lattice spacing can be detected during the release of wood maturation stress by synchrotron x-ray diffraction experiment. The lattice strain was found to be the same order of magnitude as the macroscopic strain. The fiber repeat distance, 1.033 nm evaluated for tension wood after the release of maturation stress was equal to the conventional wood values, whereas the value before stress release was larger, corresponding to a fiber repeat of 1.035 nm, nearly equal to that of cotton and ramie. Interestingly, the fiber repeat varied from 1.033 nm for wood to 1.040 nm for algal cellulose, with an increasing order of lateral size of cellulose microfibrils so far reported. These lines of experiments demonstrate that, before the stress release, the cellulose was in a state of tension, which is, to our knowledge, the first experimental evidence supporting the assumption that tension is induced in cellulose microfibrils. |
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Address |
Kyoto Univ, Res Inst Sustainable Humanosphere, Uji, Kyoto, Japan, Email: sugiyama@rish.kyoto-u.ac.jp |
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Publisher |
BIOPHYSICAL SOCIETY |
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ISSN |
0006-3495 |
ISBN |
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Notes |
ISI:000239086800039 |
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no |
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Call Number |
EcoFoG @ eric.marcon @ |
Serial |
224 |
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Author |
Almeras, T.; Yoshida, M.; Okuyama, T. |
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Title |
Strains inside xylem and inner bark of a stem submitted to a change in hydrostatic pressure |
Type |
Journal Article |
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Year |
2006 |
Publication |
Trees-Structure and Function |
Abbreviated Journal |
Trees-Struct. Funct. |
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Volume |
20 |
Issue |
4 |
Pages |
460-467 |
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Keywords |
diurnal strains; hydrostatic pressure; xylem; inner bark; mechanical properties |
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Abstract |
Tangential strains were measured with strain gauges at the surface of xylem and inner bark of saplings of Cryptomeria japonica D. Don. and Fagus silvatica L. during a pressurization test. The test consists in submitting the whole sapling to an artificially imposed hydrostatic pressure of increasing magnitude. The elastic response of the stems was found linear both at the surface of xylem and inner bark. A simple geometric model allows to compute radial strains in each tissue from tangential strain data. Inside inner bark, radial strains are much larger than tangential strains, because tangential strains are restrained by the core of wood. The material compliance of each tissue was computed as the ratio between the radial strain and the pressure that caused it. The material compliance of xylem is much lower than that of inner bark, but, as its thickness is much larger, its contribution to the apparent behavior of the stem is not negligible. Computation of material compliances by this pressurization test provides information about the specific behavior of each tissue in response to hydrostatic pressure. This can be used to estimate and interpret the calibration factor linking the water status of the plant to the apparent strain measured at its surface. |
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Address |
Nagoya Univ, Grad Sch Bioagr Sci, Lab Biomat Phys, Chikusa Ku, Nagoya, Aichi 4648601, Japan, Email: t_almeras@hotmail.com |
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Publisher |
SPRINGER |
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Abbreviated Series Title |
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Edition |
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ISSN |
0931-1890 |
ISBN |
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Notes |
ISI:000237858100007 |
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no |
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Call Number |
EcoFoG @ eric.marcon @ |
Serial |
225 |
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Author |
Ponton, S.; Flanagan, L.B.; Alstad, K.P.; Johnson, B.G.; Morgenstern, K.; Kljun, N.; Black, T.A.; Barr, A.G. |
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Title |
Comparison of ecosystem water-use efficiency among Douglas-fir forest, aspen forest and grassland using eddy covariance and carbon isotope techniques |
Type |
Journal Article |
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Year |
2006 |
Publication |
Global Change Biology |
Abbreviated Journal |
Glob. Change Biol. |
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Volume |
12 |
Issue |
2 |
Pages |
294-310 |
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Keywords |
boreal forest; conifer forest; eddy covariance; grassland; stable isotopes |
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Abstract |
Comparisons were made among Douglas-fir forest, aspen (broad leaf deciduous) forest and wheatgrass (C-3) grassland for ecosystem-level water-use efficiency (WUE). WUE was defined as the ratio of photosynthetic CO2 assimilation rate and evapotranspiration (ET) rate. The ET data measured by eddy covariance were screened so that they overwhelmingly represented transpiration. The three sites used in this comparison spanned a range of vegetation (plant functional) types and environmental conditions within western Canada. When compared in the relative order Douglas-fir (located on Vancouver Island, BC), aspen (northern Saskatchewan), grassland (southern Alberta), the sites demonstrated a progressive decline in precipitation and a general increase in maximum air temperature and atmospheric saturation deficit (D-max) during the mid-summer. The average (+/- SD) WUE at the grassland site was 2.6 +/- 0.7 mmol mol(-1), which was much lower than the average values observed for the two other sites (aspen: 5.4 +/- 2.3, Douglas-fir: 8.1 +/- 2.4). The differences in WUE among sites were primarily because of variation in ET. The highest maximum ET rates were approximately 5, 3.2 and 2.7 mm day(-1) for the grassland, aspen and Douglas-fir sites, respectively. There was a strong negative correlation between WUE and D-max for all sites. We also made seasonal measurements of the carbon isotope ratio of ecosystem respired CO2 (delta(R)) in order to test for the expected correlation between shifts in environmental conditions and changes to the ecosystem-integrated ratio of leaf intercellular to ambient CO2 concentration (c(i)/c(a)). There was a consistent increase in delta(R) values in the grassland, aspen forest and Douglas-fir forest associated with a seasonal reduction in soil moisture. Comparisons were made between WUE measured using eddy covariance with that calculated based on D and delta(R) measurements. There was excellent agreement between WUE values calculated using the two techniques. Our delta(R) measurements indicated that c(i)/c(a) values were quite similar among the Douglas-fir, aspen and grassland sites, despite large variation in environmental conditions among sites. This implied that the shorter-lived grass species had relatively high c(i)/c(a) values for the D of their habitat. By contrast, the longer-lived Douglas-fir trees were more conservative in water-use with lower c(i)/c(a) values relative to their habitat D. This illustrates the interaction between biological and environmental characteristics influencing ecosystem-level WUE. The strong correlation we observed between the two independent measurements of WUE, indicates that the stable isotope composition of respired CO2 is a useful ecosystem-scale tool to help study constraints to photosynthesis and acclimation of ecosystems to environmental stress. |
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Univ Lethbridge, Dept Biol Sci, Lethbridge, AB T1K 3M4, Canada, Email: larry.flanagan@uleth.ca |
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BLACKWELL PUBLISHING |
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1354-1013 |
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ISI:000234974900013 |
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EcoFoG @ eric.marcon @ |
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226 |
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