| Records |
| Author |
Leroy, C.; Jauneau, A.; Quilichini, A.; Dejean, A.; Orivel, J. |
| Title |
Comparison between the anatomical and morphological structure of leaf blades and foliar domatia in the ant-plant Hirtella physophora (Chrysobalanaceae) |
Type |
Journal Article |
| Year |
2008 |
Publication |
Annals of Botany |
Abbreviated Journal |
Ann. Bot. |
| Volume |
101 |
Issue |
4 |
Pages |
501-507 |
| Keywords |
anatomy; ant-plant mutualism; Chrysobalanaceae; extra-floral nectaries; French Guiana; Hirtella physophora; secondary domatia |
| Abstract |
Background and Aims Myrmecophytes, or ant-plants, are characterized by their ability to shelter colonies of some ant species in hollow structures, or ant-domatia, that are often formed by hypertrophy of the internal tissue at specific locations (i.e. trunk, branches, thorns and leaf pouches). In Hirtella physophora (Chrysobalanaceae), the focal species of this study, the ant-domatia consist of leaf pouches formed when the leaf rolls over onto itself to create two spheres at the base of the blade. Methods The morphological and anatomical changes through which foliar ant-domatia developed from the laminas are studied for the first time by using fresh and fixed mature leaves from the same H. physophora individuals. Key results Ant-domatia were characterized by larger extra-floral nectaries, longer stomatal apertures and lower stomatal density. The anatomical structure of the domatia differed in the parenchymatous tissue where palisade and spongy parenchyma were indistinct; chloroplast density was lower and lignified sclerenchymal fibres were more numerous compared with the lamina. In addition, the domatia were thicker than the lamina, largely because the parenchymatous and epidermal cells were enlarged. Conclusion Herein, the morphological and anatomical changes that permit foliar ant-domatia to be defined as a specialized leaf structure are highlighted. Similarities as well as structural modifications in the foliar ant-domatia compared with the lamina are discussed from botanical, functional and mutualistic points of view. These results are also important to understanding the reciprocal evolutionary changes in traits and, thus, the coevolutionary processes occurring in insect-plant mutualisms. |
| Address |
[Leroy, Celine; Quilichini, Angelique; Dejean, Alain; Orivel, Jerome] Univ Toulouse 3, CNRS, UMR 5174, Lab Evolut & Diversite Biol, F-31062 Toulouse 9, France, Email: orivel@cict.fr |
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| Publisher |
OXFORD UNIV PRESS |
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| ISSN |
0305-7364 |
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Notes  |
ISI:000253489700003 |
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no |
| Call Number |
EcoFoG @ eric.marcon @ |
Serial |
212 |
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| Author |
Tindo, M.; Kenne, M.; Dejean, A. |
| Title |
Advantages of multiple foundress colonies in Belonogaster juncea juncea L.: greater survival and increased productivity |
Type |
Journal Article |
| Year |
2008 |
Publication |
Ecological Entomology |
Abbreviated Journal |
Ecol. Entomol. |
| Volume |
33 |
Issue |
2 |
Pages |
293-297 |
| Keywords |
colony development; evolution of eusociality; fitness; Polistinae; productivity |
| Abstract |
1. The ecological hypothesis predicts that multiple foundress colonies of social wasps may have a better survival rate and produce more brood per capita than single foundress colonies. With the aim of verifying if these characteristics exist in the primitively eusocial wasp species Belonogaster juncea juncea (L.), we monitored 49 foundations, including 13 single and 36 multiple foundress colonies, in Cameroon. 2. Multiple foundress colonies were significantly more successful than single foundress colonies in producing at least one adult. 3. The total productivity of the colonies increased significantly with the number of associated foundresses, but the productivity per capita did not. No single foundress colony reached the sexual phase, while eight (21.6%) multiple foundress colonies did. Males were produced in only five colonies, so that the sex ratio was biased in favour of females. 4. These results suggest that because of the strong ecological constraints on solitary nesting, survival and high colony productivity are two advantages of multiple foundress colonies in B. j. juncea. 5. The decreasing per capita productivity concomitant with an increasing number of females noted in this study illustrates once again Michener's paradox. The coefficient of variance of the per capita productivity significantly decreased with group size, as Wenzel and Pickering suggested in the model they created to explain the paradox. 6. Ecological factors may act in conjunction with other factors, such as genetic relatedness between associated foundresses, to promote joining behaviour in B. j. juncea. |
| Address |
[Tindo, Maurice; Kenne, Martin] Univ Douala, Fac Sci, BP Douala, Cameroon, Email: jtindo2000@yahoo.fr |
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| Publisher |
BLACKWELL PUBLISHING |
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Edition |
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| ISSN |
0307-6946 |
ISBN |
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Conference |
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| Notes |
ISI:000253710000017 |
Approved |
no |
| Call Number |
EcoFoG @ eric.marcon @ |
Serial |
142 |
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| Author |
Vendramin, G.G.; Fady, B.; Gonzalez-Martinez, S.C.; Hu, F.S.; Scotti, I.; Sebastiani, F.; Soto, A.; Petit, R.J. |
| Title |
Genetically depauperate but widespread: The case of an emblematic mediterranean pine |
Type |
Journal Article |
| Year |
2008 |
Publication |
Evolution |
Abbreviated Journal |
Evolution |
| Volume |
62 |
Issue |
3 |
Pages |
680-688 |
| Keywords |
chloroplast microsatellites; conservation genetics; diversity depletion; human impact; Pinus pinea |
| Abstract |
Genetic variation is generally considered a prerequisite for adaptation to new environmental conditions. Thus the discovery of genetically depauperate but geographically widespread species is unexpected. We used 12 paternally inherited chloroplast microsatellites to estimate population genetic variation across the full range of an emblematic circum-Mediterranean conifer, stone pine (Pinus pinea L.). The same chloroplast DNA haplotype is fixed in nearly all of the 34 investigated populations. Such a low level of variation is consistent with a previous report of very low levels of diversity at nuclear loci in this species. Stone pine appears to have passed through a severe and prolonged demographic bottleneck, followed by subsequent natural- and human-mediated dispersal across the Mediterranean Basin. No other abundant and widespread plant species has as little genetic diversity as P. pinea at both chloroplast and nuclear markers. However, the species harbors a nonnegligible amount of variation at adaptive traits. Thus a causal relationship between genetic diversity, as measured by marker loci, and the evolutionary precariousness of a species, cannot be taken for granted. |
| Address |
[Vendramin, Giovanni G.] Ist Genet Vegetale, Sez Firenze, Florence, Italy, Email: petit@pierroton.inra.fr |
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| Publisher |
BLACKWELL PUBLISHING |
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Series Issue |
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Edition |
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| ISSN |
0014-3820 |
ISBN |
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| Notes |
ISI:000253758600016 |
Approved |
no |
| Call Number |
EcoFoG @ eric.marcon @ |
Serial |
141 |
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| Author |
Coutand, C.; Dupraz, C.; Jaouen, G.; Ploquin, S.; Adam, B. |
| Title |
Mechanical stimuli regulate the allocation of biomass in trees: Demonstration with young Prunus avium trees |
Type |
Journal Article |
| Year |
2008 |
Publication |
Annals of Botany |
Abbreviated Journal |
Ann. Bot. |
| Volume |
101 |
Issue |
9 |
Pages |
1421-1432 |
| Keywords |
Prunus avium; growth; mechanical stress; bending; biomass; shoot/root ratio; wind; shelter |
| Abstract |
Background and Aims Plastic tree-shelters are increasingly used to protect tree seedlings against browsing animals and herbicide drifts. The biomass allocation in young seedlings of deciduous trees is highly disturbed by common plastic tree-shelters, resulting in poor root systems and reduced diameter growth of the trunk. The shelters have been improved by creating chimney-effect ventilation with holes drilled at the bottom, resulting in stimulated trunk diameter growth, but the root deficit has remained unchanged. An experiment was set up to elucidate the mechanisms behind the poor root growth of sheltered Prunus avium trees. Methods Tree seedlings were grown either in natural windy conditions or in tree-shelters. Mechanical wind stimuli were suppressed in ten unsheltered trees by staking. Mechanical stimuli (bending) of the stem were applied in ten sheltered trees using an original mechanical device. Key Results Sheltered trees suffered from poor root growth, but sheltered bent trees largely recovered, showing that mechano-sensing is an important mechanism governing C allocation and the shoot-root balance. The use of a few artificial mechanical stimuli increased the biomass allocation towards the roots, as did natural wind sway. It was demonstrated that there was an acclimation of plants to the imposed strain. Conclusions This study suggests that if mechanical stimuli are used to control plant growth, they should be applied at low frequency in order to be most effective. The impact on the functional equilibrium hypothesis that is used in many tree growth models is discussed. The consequence of the lack of mechanical stimuli should be incorporated in tree growth models when applied to environments protected from the wind (e.g. greenhouses, dense forests). |
| Address |
[Coutand, Catherine; Jaouen, Gaelle; Ploquin, Stephane; Adam, Boris] Univ Clermont Ferrand, INRA, UMR PIAF, F-63100 Clermont Ferrand, France, Email: coutand@clermont.inra.fr |
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| Publisher |
OXFORD UNIV PRESS |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0305-7364 |
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:000255987500013 |
Approved |
no |
| Call Number |
EcoFoG @ eric.marcon @ |
Serial |
211 |
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| Author |
Hattenschwiler, S.; Aeschlimann, B.; Couteaux, M.M.; Roy, J.; Bonal, D. |
| Title |
High variation in foliage and leaf litter chemistry among 45 tree species of a neotropical rainforest community |
Type |
Journal Article |
| Year |
2008 |
Publication |
New Phytologist |
Abbreviated Journal |
New Phytol. |
| Volume |
179 |
Issue |
1 |
Pages |
165-175 |
| Keywords |
French Guiana; interspecific and intraspecific variation; leaf litter traits; neotropical rainforest; nitrogen; nutrient resorption; phosphorus; stoichiometry |
| Abstract |
Distinct ecosystem level carbon : nitrogen : phosphorus (C : N : P) stoichiometries in forest foliage have been suggested to reflect ecosystem-scale selection for physiological strategies in plant nutrient use. Here, this hypothesis was explored in a nutrient-poor lowland rainforest in French Guiana. Variation in C, N and P concentrations was evaluated in leaf litter and foliage from neighbour trees of 45 different species, and the litter concentrations of major C fractions were also measured. Litter C ranged from 45.3 to 52.4%, litter N varied threefold (0.68-2.01%), and litter P varied seven-fold (0.009-0.062%) among species. Compared with foliage, mean litter N and P concentrations decreased by 30% and 65%, respectively. Accordingly, the range in mass-based N : P shifted from 14 to 55 in foliage to 26 to 105 in litter. Resorption proficiencies indicated maximum P withdrawal in most species, but with a substantial increase in variation in litter P compared with foliage. These data suggest that constrained ecosystem-level C : N : P ratios do not preclude the evolution of highly diversified strategies of nutrient use and conservation among tropical rainforest tree species. The resulting large variation in litter quality will influence stoichiometric constraints within the decomposer food web, with potentially far-ranging consequences on nutrient dynamics and plant-soil feedbacks. |
| Address |
[Haettenschwiler, Stephan; Aeschlimann, Beat; Couteaux, Marie-Madeleine; Roy, Jacques] CEFE, CNRS, F-34293 Montpellier 5, France, Email: stephan.hattenschwiler@cefe.cnrs.fr |
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| Publisher |
BLACKWELL PUBLISHING |
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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 |
0028-646X |
ISBN |
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| Notes |
ISI:000256412500017 |
Approved |
no |
| Call Number |
EcoFoG @ eric.marcon @ |
Serial |
139 |
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| Author |
Dejean, A.; Djieto-Lordon, C.; Cereghino, R.; Leponce, M. |
| Title |
Ontogenetic succession and the ant mosaic: An empirical approach using pioneer trees |
Type |
Journal Article |
| Year |
2008 |
Publication |
Basic and Applied Ecology |
Abbreviated Journal |
Basic Appl. Ecol. |
| Volume |
9 |
Issue |
3 |
Pages |
316-323 |
| Keywords |
ant-plant relationships; dynamics of associations; myrmecophytes; species turnover; tropical rainforests |
| Abstract |
Arboreal ant mosaics have been intensively investigated, but what generates these mosaics remains poorly understood. In this paper, we hypothesize that the dynamics of arboreal ant mosaics could be better understood by examining the ontogenetic succession of ants in tropical trees. We used three African pioneer tree species as biological models. Lophira alata (Ochnaceae) is a long-lived species that does not furnish any reward (i.e., extra-floral nectaries [EFNs], shelter) to ants, Anthocleista vogelii (Gentianaceae) bears extremely well-developed EFNs, and Barteria fistulosa (Passifloraceae) is a long-lived myrmecophyte providing both EFNs and domatia. For both L. alata and A. vogelii, we noted a succession of different associated ants as the plants grew and aged. Ground-nesting, arborealforaging ant species were the first associates, followed by arboreal species that build nests with the leaves of their host trees, together with some species nesting opportunistically in pre-existing cavities. Carton-building Crematogaster species were the last in this succession. The presence of EFNs on A. vogelii slows species turnover, demonstrating that the plant exerts some control over its ant associates. The comparison with B. fistulosa, which generally remains associated with the same plant-ant species during its entire ontogeny, highlights the importance of the selective attractiveness of the trees for their associated ants – or, perhaps, the existence of plant filters that screen arriving ants. (C) 2007 Gesellschaft fur Okologie. Published by Elsevier GmbH. All rights reserved. |
| Address |
[Dejean, Alain] CNRS Guyane, UPS 2561, F-97300 Cayenne, France, Email: alain.dejean@wanadoo.fr |
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| Publisher |
ELSEVIER GMBH, URBAN & FISCHER VERLAG |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
1439-1791 |
ISBN |
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| Notes |
ISI:000256734600013 |
Approved |
no |
| Call Number |
EcoFoG @ eric.marcon @ |
Serial |
138 |
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| Author |
Scotti, I.; Gugerli, F.; Pastorelli, R.; Sebastiani, F.; Vendramin, G.G. |
| Title |
Maternally and paternally inherited molecular markers elucidate population patterns and inferred dispersal processes on a small scale within a subalpine stand of Norway spruce (Picea abies [L.] Karst.) |
Type |
Journal Article |
| Year |
2008 |
Publication |
Forest Ecology and Management |
Abbreviated Journal |
For. Ecol. Manage. |
| Volume |
255 |
Issue |
11 |
Pages |
3806-3812 |
| Keywords |
chloroplast microsatellites; mitochondrial minisatellites; pollen/seed dispersal; demography; spatial autocorrelation |
| Abstract |
The within-population spatial structure of genetic diversity is shaped by demographic processes, including historical accidents such as forest perturbations. Information drawn from the analysis of the spatial distribution of genetic diversity is therefore inherently linked to demographic-historical processes that ultimately determine the fate of populations. All adult trees and saplings in a 1.4-ha plot within a mixed Norway spruce (Picea abies [L.] Karst) stand were characterised by means of chloroplast (paternally inherited) markers, and a large sub-sample of these were genotyped at mitochondrial (maternally inherited) molecular markers. These data were used to analyse the spatial distribution of genetic variation and to compare the patterns corresponding to the two marker types. The plot presented non-homogeneous local stem density in the younger cohorts, and the indirect effect of this source of variation on the spatial genetic structure was investigated. Results suggest that (i) spatially limited seed dispersal induced patchiness in genotype distribution, while pollen flow had a homogenising effect; (ii) deviations from random spatial structure were stronger in the demographically most stable portions of the stand, while they were weaker where sudden bursts of regeneration occurred; (iii) spatially overlapping adult and sapling cohorts displayed the same spatial genetic structure (stronger on stable areas, weaker in portions of the stand undergoing events of intense regeneration), which was substantiated by the influence of local demographic processes. Regeneration dynamics as modulated by demography thus influences the distribution of genetic diversity within the stand both in the younger life stages and in the adult population. (C) 2008 Elsevier B.V. All rights reserved. |
| Address |
[Scotti, I.] INRA, UMR 0745, ECOFOG, F-97387 Kourou, France, Email: ivan.scotti@kourou.cirad.fr |
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| Publisher |
ELSEVIER SCIENCE BV |
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Edition |
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| ISSN |
0378-1127 |
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| Notes |
ISI:000257019100019 |
Approved |
no |
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EcoFoG @ eric.marcon @ |
Serial |
137 |
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| Author |
Christensen-Dalsgaard, K.K.; Ennos, A.R.; Fournier, M. |
| Title |
Are radial changes in vascular anatomy mechanically induced or an ageing process? Evidence from observations on buttressed tree root systems |
Type |
Journal Article |
| Year |
2008 |
Publication |
Trees-Structure and Function |
Abbreviated Journal |
Trees-Struct. Funct. |
| Volume |
22 |
Issue |
4 |
Pages |
543-550 |
| Keywords |
wood; anatomy; mechanical loading; tree development; vessels |
| Abstract |
To investigate the effect of changes in mechanical loading conditions on radial anatomical patterns, we here compare the trunk with the roots in two locations of three species of buttressed trees. The proximal part of the buttress roots is highly mechanically loaded throughout juvenile growth whereas the distal part of the buttresses is though to be mechanically unimportant at formation but become progressively more mechanically loaded during growth. We measured the frequency and diameter of the vessels and the vessel area fraction, and from this calculated the specific conductivity of tissue samples of the core-, intermediate- and outer wood. As in previous studies there was an increase in vessel size, vessel area fraction and specific conductivity from the pith to the bark in the trunk. In the proximal part of the buttress roots, however, there was no increase in vessel size and conductivity from core wood and out in agreement with the high mechanical loading found here throughout growth. There was instead a decrease in vessel size, vessel area fraction and specific conductivity from core- to outer wood in the distal part of the buttress roots in accordance with the increase in mechanical loading. Hence, it appears that the radial anatomical patterns are not a passive function of cambial ageing but may be modified in response to local mechanical loading. |
| Address |
[Christensen-Dalsgaard, Karen K.] Univ Alberta, Edmonton, AB T6G 2E3, Canada, Email: kkchrist@ualberta.ca |
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SPRINGER |
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Edition |
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| ISSN |
0931-1890 |
ISBN |
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| Notes |
ISI:000257385200014 |
Approved |
no |
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EcoFoG @ eric.marcon @ |
Serial |
136 |
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| Author |
Herault, B.; Thoen, D. |
| Title |
Diversity of plant assemblages in isolated depressional wetlands from Central-Western Europe |
Type |
Journal Article |
| Year |
2008 |
Publication |
Biodiversity and Conservation |
Abbreviated Journal |
Biodivers. Conserv. |
| Volume |
17 |
Issue |
9 |
Pages |
2169-2183 |
| Keywords |
closed depressions; connectivity; fens; forest; grassland; habitat area; landscape matrix |
| Abstract |
A closed depression is defined as a geomorphologic element where a sediment depository is encircled by hillslopes. Despite the fact that closed depressions are often the only stagnant water points in many European landscapes, few ecological researches on their plant assemblages have been done. The main goal of this study was to give first results of the environmental factors responsible for the vegetation composition, richness and rarity in the closed depressions of the Lorraine biogeographical district (Belgium, France and grand-duche de Luxembourg). We surveyed for plant presence 85 forest and 77 grassland closed depressions. For each site, wetland area, local environmental factors and regional connectivities registered. For each species, the Ellenberg values were compiled. To investigate the main source of variation in species composition and in species richness (including richness in rare species), Non-metric Multidimensional Scaling analyses and Generalized Linear Models were respectively used. Species pools in forest (forest and preforest species) and in grassland (bog plants, pioneers, helophytes) were quite different. In both landscapes, a gradient from plants typical of basic high-productive soils to plants typical of acid low-productive soils reflects a shared successional gradient. The accumulation of organic matter allowed the establishment of Sphagnum spp., which slowly acidified the soil and thus acted as ecosystem engineers for the arrival of bog plants. Moreover, the species composition was additionally driven by the plant light tolerance in forests and by the plant water requirements in grasslands. Mechanisms of species accumulation (increase in species richness) were different in forests and in grasslands: respectively related to the plant light tolerance and to the wetland area. At the regional level, the averaged soil productivity was negatively related to the richness in rare species. Indeed, perennial highly-competitive plants such as Glyceria spp., Iris pseudacorus or Urtica dioica impeded the establishment of smaller and rarer species. At the habitat level, isolated closed depressions (due to either low connectivity or low grazing pressure) have more habitat rare species, giving evidences of dispersal limitation in plant assemblages of closed depressions. |
| Address |
[Herault, Bruno] Inst Bot, Ctr Ecol Vegetale & Hydrol, F-67083 Strasbourg, France, Email: bruno.herault@cirad.fr |
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SPRINGER |
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Edition |
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| ISSN |
0960-3115 |
ISBN |
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| Notes |
ISI:000257486400008 |
Approved |
no |
| Call Number |
EcoFoG @ eric.marcon @ |
Serial |
135 |
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| Author |
Bonal, D.; Bosc, A.; Ponton, S.; Goret, J.Y.; Burban, B.; Gross, P.; Bonnefond, J.M.; Elbers, J.; Longdoz, B.; Epron, D.; Guehl, J.M.; Granier, A. |
| Title |
Impact of severe dry season on net ecosystem exchange in the Neotropical rainforest of French Guiana |
Type |
Journal Article |
| Year |
2008 |
Publication |
Global Change Biology |
Abbreviated Journal |
Glob. Change Biol. |
| Volume |
14 |
Issue |
8 |
Pages |
1917-1933 |
| Keywords |
dry season; ecosystem respiration; eddy covariance; gross ecosystem productivity; Neotropical rainforest; net ecosystem productivity; soil drought; solar radiation |
| Abstract |
The lack of information on the ways seasonal drought modifies the CO2 exchange between Neotropical rainforest ecosystems and the atmosphere and the resulting carbon balance hinders our ability to precisely predict how these ecosystems will respond as global environmental changes force them to face increasingly contrasting conditions in the future. To address this issue, seasonal variations in daily net ecosystem productivity (NEPd) and two main components of this productivity, daily total ecosystem respiration (R-Ed) and daily gross ecosystem productivity (GEP(d)), were estimated over 2 years at a flux tower site in French Guiana, South America (5 degrees 16'54'N, 52 degrees 54'44'W). We compared seasonal variations between wet and dry periods and between dry periods of contrasting levels of intensity (i.e. mild vs. severe) during equivalent 93-day periods. During the wet periods, the ecosystem was almost in balance with the atmosphere (storage of 9.0 g C m(-2)). Seasonal dry periods, regardless of their severity, are associated with higher incident radiation and lower R-Ed combined with reduced soil respiration associated with low soil water availability. During the mild dry period, as is normally the case in this region, the amount of carbon stored in the ecosystem was 32.7 g C m(-2). Severe drought conditions resulted in even lower R-Ed, whereas the photosynthetic activity was only moderately reduced and no change in canopy structure was observed. Thus, the severe dry period was characterized by greater carbon storage (64.6 g C m(-2)), emphasizing that environmental conditions, such as during a severe drought, modify the CO2 exchange between Neotropical rainforest ecosystems and the atmosphere and potentially the resulting carbon balance. |
| Address |
[Bonal, Damien; Goret, Jean-Yves; Burban, Benoit] INRA, UMR Ecol Forets Guyane, Kourou 97387, French Guiana, Email: damien.bonal@kourou.cirad.fr |
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BLACKWELL PUBLISHING |
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Edition |
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1354-1013 |
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| Notes |
ISI:000257712400015 |
Approved |
no |
| Call Number |
EcoFoG @ eric.marcon @ |
Serial |
133 |
| Permanent link to this record |
