toggle visibility Search & Display Options

Select All    Deselect All
 |   | 
Details
   print
  Records Links
Author Paine, C.E.T.; Harms, K.E.; Schnitzer, S.A.; Carson, W.P. openurl 
  Title Weak competition among tropical tree seedlings: Implications for species coexistence Type Journal Article
  Year 2008 Publication Biotropica Abbreviated Journal Biotropica  
  Volume 40 Issue 4 Pages 432-440  
  Keywords Brosimum alicastrum; competitive irrelevance; maintenance of biodiversity; Matisia cordata; resource competition; Panama; Peru; Pouteria reticulata; zone of influence  
  Abstract The intensity of competition among forest tree seedlings is poorly understood, but has important ramifications for their recruitment and for the maintenance of species diversity. Intense competition among seedlings could allow competitively dominant species to exclude subordinate species. Alternatively, the low density and small stature of forest tree seedlings could preclude intense interseedling competition. In this case, other processes, such as size-asymmetric competition with adults, interactions with consumers, or neutral dynamics would prevail as those structuring the forest understory. We tested the intensity of, and potential for, intraspecific competition among tree seedlings of three species (Brosimum alicastrum, Matisia cordata, and Pouteria reticulata) in two Neotropical rain forests. We reduced stem densities by up to 90 percent and monitored individual growth and survival rates for up to 24 mo. Individual growth and survival rates were generally unrelated to stem density. Contrary to the predicted behavior of intensely competing plant populations, the distribution of individual heights did not become more left-skewed with time for any species, regardless of plot density; i.e., excesses of short, suppressed individuals did not accumulate in high-density plots. We further measured the overlap of zones of influence (ZOIs) to assess the potential for resource competition. Seedling ZOIs overlapped only slightly in extremely dense monodominant plots, and even less in ambient-density plots of mixed composition. Our results thus suggest that interseedling competition was weak. Given the low density of tree seedlings in Neotropical forests, we infer that resource competition among seedlings may be irrelevant to their recruitment.  
  Address [Paine, C. E. Timothy; Harms, Kyle E.] Louisiana State Univ, Dept Biol Sci, Baton Rouge, LA 70803 USA, Email: cetpaine@gmail.com  
  Corporate Author Thesis  
  Publisher BLACKWELL PUBLISHING Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0006-3606 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000257717500006 Approved no  
  Call Number (up) EcoFoG @ eric.marcon @ Serial 134  
Permanent link to this record
 

 
Author Herault, B.; Thoen, D. openurl 
  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  
  Corporate Author Thesis  
  Publisher SPRINGER Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0960-3115 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000257486400008 Approved no  
  Call Number (up) EcoFoG @ eric.marcon @ Serial 135  
Permanent link to this record
 

 
Author Christensen-Dalsgaard, K.K.; Ennos, A.R.; Fournier, M. openurl 
  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  
  Corporate Author Thesis  
  Publisher SPRINGER Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0931-1890 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000257385200014 Approved no  
  Call Number (up) EcoFoG @ eric.marcon @ Serial 136  
Permanent link to this record
 

 
Author Scotti, I.; Gugerli, F.; Pastorelli, R.; Sebastiani, F.; Vendramin, G.G. openurl 
  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  
  Corporate Author Thesis  
  Publisher ELSEVIER SCIENCE BV Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0378-1127 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000257019100019 Approved no  
  Call Number (up) EcoFoG @ eric.marcon @ Serial 137  
Permanent link to this record
 

 
Author Dejean, A.; Djieto-Lordon, C.; Cereghino, R.; Leponce, M. openurl 
  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  
  Corporate Author Thesis  
  Publisher ELSEVIER GMBH, URBAN & FISCHER VERLAG Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1439-1791 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000256734600013 Approved no  
  Call Number (up) EcoFoG @ eric.marcon @ Serial 138  
Permanent link to this record
 

 
Author Hattenschwiler, S.; Aeschlimann, B.; Couteaux, M.M.; Roy, J.; Bonal, D. openurl 
  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  
  Corporate Author Thesis  
  Publisher BLACKWELL PUBLISHING Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0028-646X ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000256412500017 Approved no  
  Call Number (up) EcoFoG @ eric.marcon @ Serial 139  
Permanent link to this record
 

 
Author Grangier, J.; Dejean, A.; Male, P.J.G.; Orivel, J. openurl 
  Title Indirect defense in a highly specific ant-plant mutualism Type Journal Article
  Year 2008 Publication Naturwissenschaften Abbreviated Journal Naturwissenschaften  
  Volume 95 Issue 10 Pages 909-916  
  Keywords Allomerus decemarticulatus; Hirtella physophora; indirect defense; myrmecophytes; optimal defense theory  
  Abstract Although associations between myrmecophytes and their plant ants are recognized as a particularly effective form of protective mutualism, their functioning remains incompletely understood. This field study examined the ant-plant Hirtella physophora and its obligate ant associate Allomerus decemarticulatus. We formulated two hypotheses on the highly specific nature of this association: (1) Ant presence should be correlated with a marked reduction in the amount of herbivory on the plant foliage; (2) ant activity should be consistent with the “optimal defense” theory predicting that the most vulnerable and valuable parts of the plant are the best defended. We validated the first hypothesis by demonstrating that for ant-excluded plants, expanding leaves, but also newly matured ones in the long term, suffered significantly more herbivore damage than ant-inhabited plants. We showed that A. decemarticulatus workers represent both constitutive and inducible defenses for their host, by patrolling its foliage and rapidly recruiting nestmates to foliar wounds. On examining how these activities change according to the leaves' developmental stage, we found that the number of patrolling ants dramatically decreased as the leaves matured, while leaf wounds induced ant recruitment regardless of the leaf's age. The resulting level of these indirect defenses was roughly proportional to leaf vulnerability and value during its development, thus validating our second hypothesis predicting optimal protection. This led us to discuss the factors influencing ant activity on the plant's surface. Our study emphasizes the importance of studying both the constitutive and inducible components of indirect defense when evaluating its efficacy and optimality.  
  Address [Grangier, Julien; Dejean, Alain; Male, Pierre-Jean G.; Orivel, Jerome] Univ Toulouse 3, Lab Evolut & Diversite Biol, CNRS, UMR 5174, F-31062 Toulouse 9, France, Email: grangier@cict.fr  
  Corporate Author Thesis  
  Publisher SPRINGER Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0028-1042 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000259737600002 Approved no  
  Call Number (up) EcoFoG @ eric.marcon @ Serial 207  
Permanent link to this record
 

 
Author Vendramin, G.G.; Fady, B.; Gonzalez-Martinez, S.C.; Hu, F.S.; Scotti, I.; Sebastiani, F.; Soto, A.; Petit, R.J. openurl 
  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  
  Corporate Author Thesis  
  Publisher BLACKWELL PUBLISHING Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0014-3820 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000253758600016 Approved no  
  Call Number (up) EcoFoG @ eric.marcon @ Serial 141  
Permanent link to this record
 

 
Author Tindo, M.; Kenne, M.; Dejean, A. openurl 
  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  
  Corporate Author Thesis  
  Publisher BLACKWELL PUBLISHING Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0307-6946 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000253710000017 Approved no  
  Call Number (up) EcoFoG @ eric.marcon @ Serial 142  
Permanent link to this record
 

 
Author Brendel, O.; Le Thiec, D.; Scotti-Saintagne, C.; Bodenes, C.; Kremer, A.; Guehl, J.M. openurl 
  Title Quantitative trait loci controlling water use efficiency and related traits in Quercus robur L Type Journal Article
  Year 2008 Publication Tree Genetics & Genomes Abbreviated Journal Tree Genet. Genomes  
  Volume 4 Issue 2 Pages 263-278  
  Keywords Quercus robur; carbon isotope composition; delta C-13; water use efficiency; QTL  
  Abstract Genetic variation for intrinsic water use efficiency (W-i) and related traits was estimated in a full-sib family of Quercus robur L. over 3 years. The genetic linkage map available for this F1 family was used to locate quantitative trait loci (QTL) for W-i, as estimated by leaf carbon stable isotope composition (delta C-13) or the ratio of net CO2 assimilation rate (A) to stomatal conductance to water vapour (g(w)) and related leaf traits. Gas exchange measurements were used to standardize estimates of A and g(w) and to model the sensitivity of gw to leaf-to-air vapour pressure deficit (sg(VPD)). delta C-13 varied by more than 3% among the siblings, which is equivalent to 40% variation of W-i. Most of the studied traits exhibited high clonal mean repeat-abilities (> 50%; proportion of clonal mean variability in global variance). Repeatabilities for delta C-13, leaf mass per area (LMA) and leaf nitrogen content were higher than 70%. For delta C-13, ten QTLs were detected, one of which was detected repeatedly for all 3 years and consistently explained more than 20% of measured variance. Four genomic regions were found in which co-localizing traits linked variation in W-i to variations in leaf chlorophyll and nitrogen content, LMA and sg(VPD). A positive correlation using clonal means between delta C-13 and A/g(w), as well as a co-localisation of QTL detected for both traits, can be seen as validation of the theoretical model linking the genetic architecture of these two traits.  
  Address [Brendel, Oliver; Le Thiec, Didier; Guehl, Jean-Marc] Ctr INRA Nancy, UMR INRA UHP 1137, F-54280 Seichamps, France, Email: brendel@nancy.inra.fr  
  Corporate Author Thesis  
  Publisher SPRINGER HEIDELBERG Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1614-2942 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000253091100013 Approved no  
  Call Number (up) EcoFoG @ eric.marcon @ Serial 143  
Permanent link to this record
Select All    Deselect All
 |   | 
Details
   print

Save Citations:
Export Records: