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Baraloto, C.; Herault, B.; Paine, C.E.T.; Massot, H.; Blanc, L.; Bonal, D.; Molino, J.-F.; Nicolini, E.A.; Sabatier, D. |
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Contrasting taxonomic and functional responses of a tropical tree community to selective logging |
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Journal Article |
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2012 |
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Journal of Applied Ecology |
Abbreviated Journal |
J. Appl. Ecol. |
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49 |
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4 |
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861-870 |
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Canopy gap dynamics; Disturbance; French Guiana; Functional diversity; Functional evenness; Functional traits; Light partitioning; Species richness; Tropical rain forest |
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1.Considerable debate surrounds the extent to which tropical forests can be managed for resource extraction while conserving biodiversity and ecosystem properties, which depend on functional composition. Here we evaluate the compatibility of these aims by examining the effects of logging on taxonomic and functional diversity and composition in a tropical forest. 2.Twenty years after selective logging, we inventoried 4140 stems regenerating in logging gaps and adjacent undisturbed areas, and we integrated a database of 13 functional traits describing leaf and wood economics of tropical trees. 3.We found no differences in taxonomic and functional richness among habitats, but logging gaps had significantly higher taxonomic and functional evenness. 4.Logging also effected striking, long-term changes in both species and functional composition. In particular, the xylem density of recruits in logging gaps was 6% less than in unlogged forests, leaves were 11% less tough and had 6-13% greater mineral nutrient concentrations. 5.Synthesis and applications. Our results suggest that managers of tropical forests should limit overall surface area converted to logging gaps by creating fewer, larger gaps during selective logging, to reduce impacts on the taxonomic and functional composition of the regenerating stand. Our results suggest that managers of tropical forests should limit overall surface area converted to logging gaps by creating fewer, larger gaps during selective logging, to reduce impacts on the taxonomic and functional composition of the regenerating stand. © 2012 The Authors. Journal of Applied Ecology © 2012 British Ecological Society. |
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CIRAD-ES, Research Unit 'Biens et Services des Ecosystémes Forestiers tropicaux', Embrapa Amazonia Oriental, Caixa Postal, 48, Belem, Para – CEP 66095-100, Brazil |
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00218901 (Issn) |
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Export Date: 30 July 2012; Source: Scopus; Coden: Japea; doi: 10.1111/j.1365-2664.2012.02164.x; Language of Original Document: English; Correspondence Address: Baraloto, C.; INRA, UMR 'Ecologie des Forêts de Guyane', 97387 Kourou Cedex, French Guiana; email: chris.baraloto@ecofog.gf |
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EcoFoG @ webmaster @ |
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410 |
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Dejean, A.; Corbara, B.; Azémar, F.; Carpenter, J.M. |
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Title |
When attempts at robbing prey turn fatal |
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Journal Article |
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Year |
2012 |
Publication |
Naturwissenschaften |
Abbreviated Journal |
Naturwissenschaften |
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99 |
Issue |
7 |
Pages |
579-582 |
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Ant predation; Azteca andreae; Cleptobiosis; Flies and dung beetles; Myrmecophyte; Reduviidae; Socialwasps; Stinglessbees |
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Because group-hunting arboreal ants spread-eagle insect prey for a long time before retrieving them, these prey can be coveted by predatory flying insects. Yet, attempting to rob these prey is risky if the ant species is also an effective predator. Here, we show that trying to rob prey from Azteca andreae workers is a fatal error as 268 out of 276 potential cleptobionts (97.1 %) were captured in turn. The ant workers hunt in a group and use the “Velcro®” principle to cling firmly to the leaves of their host tree, permitting them to capture very large prey. Exceptions were one social wasp, plus some Trigona spp. workers and flies that landed directly on the prey and were able to take off immediately when attacked. We conclude that in this situation, previously captured prey attract potential cleptobionts that are captured in turn in most of the cases. © Springer-Verlag 2012. |
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Division of Invertebrate Zoology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024, United States |
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00281042 (Issn) |
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Export Date: 30 July 2012; Source: Scopus; Coden: Natwa; doi: 10.1007/s00114-012-0929-x; Language of Original Document: English; Correspondence Address: Dejean, A.; CNRS, Écologie des Forêts de Guyane (UMR-CNRS 8172), Campus agronomique, BP 316, 97379 Kourou cedex, France; email: alain.dejean@wanadoo.fr |
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EcoFoG @ webmaster @ |
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417 |
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Coté, G.G.; Gibernau, M. |
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Distribution of calcium oxalate crystals in floral organs of araceae in relation to pollination strategy |
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Journal Article |
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2012 |
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American Journal of Botany |
Abbreviated Journal |
Am. J. Bot. |
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99 |
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7 |
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1231-1242 |
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Araceae; Beetles; Calcium oxalate; Crystal; Defense; Flowers; Herbivory; Pollination |
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Premise of the study: Many flowers are pollinated by potentially hungry insects, yet flowers also contain gametes and embryos which must be protected from predation. Microscopic calcium oxalate crystals in plant tissues have been proposed to protect against herbivory. Aroids, which have an unusual diversity of such crystals, also exhibit diverse pollination strategies. Many species have pollinators that do not feed while visiting the flowers, while other species, especially those pollinated by beetles, offer sterile staminodia as food rewards. We examined flowers of 21 aroid species with various pollination strategies to test the hypothesis that crystals protect vital gametes and embryos while allowing consumption of food bribes.Methods: Aroid inflorescences collected from the field or from greenhouse material were sectioned, cleared, and examined by bright field and polarization microscopy.Key results: All species examined, regardless of pollination strategy, arrayed crystals around unshed pollen and ovules. Less vital tissues, such as odoriferous appendages, had few crystals. Staminodia offered as food to beetle pollinators, however, differed greatly between species in their crystal contents. Some had minimal crystals; some had crystals in patterns suggesting they limit beetle feeding; still others had abundant crystals in no obvious pattern.Conclusions: The results are consistent with crystals protecting against insect predation of gametes and embryos. However, the role of crystals in food-bribe staminodia is unclear. They may limit and direct feeding by beetles in some species, while in others they might have no protective role. © 2012 Botanical Society of America. |
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CNRS-Ecolog (UMR 8172), Campus Agronomique BP316, Korou cedex 97379, France |
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00029122 (Issn) |
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Export Date: 10 August 2012; Source: Scopus; Coden: Ajboa; doi: 10.3732/ajb.1100499; Language of Original Document: English; Correspondence Address: Coté, G. G.; Biology Department, Radford University, Radford, VA 24142-6931, United States; email: gcote@radford.edu |
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EcoFoG @ webmaster @ |
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420 |
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Barthe, S.; Gugerli, F.; Barkley, N.A.; Maggia, L.; Cardi, C.; Scotti, I. |
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Always look on both sides: Phylogenetic information conveyed by simple sequence repeat allele sequences |
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Journal Article |
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2012 |
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PLoS ONE |
Abbreviated Journal |
PLoS ONE |
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7 |
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7 |
Pages |
e40699 |
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Simple sequence repeat (SSR) markers are widely used tools for inferences about genetic diversity, phylogeography and spatial genetic structure. Their applications assume that variation among alleles is essentially caused by an expansion or contraction of the number of repeats and that, accessorily, mutations in the target sequences follow the stepwise mutation model (SMM). Generally speaking, PCR amplicon sizes are used as direct indicators of the number of SSR repeats composing an allele with the data analysis either ignoring the extent of allele size differences or assuming that there is a direct correlation between differences in amplicon size and evolutionary distance. However, without precisely knowing the kind and distribution of polymorphism within an allele (SSR and the associated flanking region (FR) sequences), it is hard to say what kind of evolutionary message is conveyed by such a synthetic descriptor of polymorphism as DNA amplicon size. In this study, we sequenced several SSR alleles in multiple populations of three divergent tree genera and disentangled the types of polymorphisms contained in each portion of the DNA amplicon containing an SSR. The patterns of diversity provided by amplicon size variation, SSR variation itself, insertions/deletions (indels), and single nucleotide polymorphisms (SNPs) observed in the FRs were compared. Amplicon size variation largely reflected SSR repeat number. The amount of variation was as large in FRs as in the SSR itself. The former contributed significantly to the phylogenetic information and sometimes was the main source of differentiation among individuals and populations contained by FR and SSR regions of SSR markers. The presence of mutations occurring at different rates within a marker's sequence offers the opportunity to analyse evolutionary events occurring on various timescales, but at the same time calls for caution in the interpretation of SSR marker data when the distribution of within-locus polymorphism is not known. |
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Unité Mixte de Recherche Ecologie des forêts de Guyane, Institut National de la Recherche Agronomique, Kourou, French Guiana |
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19326203 (Issn) |
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Export Date: 30 July 2012; Source: Scopus; Art. No.: e40699; doi: 10.1371/journal.pone.0040699; Language of Original Document: English; Correspondence Address: Scotti, I.; Unité Mixte de Recherche Ecologie des forêts de Guyane, Institut National de la Recherche Agronomique, Kourou, French Guiana; email: ivan.scotti@ecofog.gf |
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EcoFoG @ webmaster @ |
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416 |
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Dejean, A.; Carpenter, J.M.; Corbara, B.; Wright, P.; Roux, O.; LaPierre, L.M. |
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The hunter becomes the hunted: When cleptobiotic insects are captured by their target ants |
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Journal Article |
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2012 |
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Naturwissenschaften |
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99 |
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4 |
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265-273 |
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Ant predation; Cleptobiosis; Flies and Reduviidae; Myrmecophyte; Social wasps; Stingless bees |
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Here we show that trying to rob prey (cleptobiosis) from a highly specialized predatory ant species is risky. To capture prey, Allomerus decemarticulatus workers build gallery-shaped traps on the stems of their associated myrmecophyte, Hirtella physophora. We wondered whether the frequent presence of immobilized prey on the trap attracted flying cleptoparasites. Nine social wasp species nest in the H. physophora foliage; of the six species studied, only Angiopolybia pallens rob prey from Allomerus colonies. For those H. physophora not sheltering wasps, we noted cleptobiosis by stingless bees (Trigona), social wasps (A. pallens and five Agelaia species), assassin bugs (Reduviidae), and flies. A relationship between the size of the robbers and their rate of capture by ambushing Allomerus workers was established for social wasps; small wasps were easily captured, while the largest never were. Reduviids, which are slow to extract their rostrum from prey, were always captured, while Trigona and flies often escaped. The balance sheet for the ants was positive vis-à-vis the reduviids and four out of the six social wasp species. For the latter, wasps began by cutting up parts of the prey's abdomen and were captured (or abandoned the prey) before the entire abdomen was retrieved so that the total weight of the captured wasps exceeded that of the prey abdomens. For A. pallens, we show that the number of individuals captured during attempts at cleptobiosis increases with the size of the Allomerus' prey. © Springer-Verlag 2012. |
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Department of Biology, Lower Columbia College, 1600 Maple St., Longview, WA 98632, United States |
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Cited By (since 1996): 1; Export Date: 16 January 2013; Source: Scopus |
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EcoFoG @ webmaster @ |
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458 |
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Salvin, P.; Roos, C.; Robert, F. |
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Tropical mangrove sediments as a natural inoculum for efficient electroactive biofilms |
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2012 |
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Bioresource Technology |
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Bioresour. Technol. |
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120 |
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45-51 |
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Chronoamperometry; Cyclic voltammetry; Electroactive biofilms; Microbial fuel cells; Three-electrode systems |
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Chronoamperometry is known to be an efficient way to form electroactive biofilms (EAB) on conductive electrodes. For the first time, tropical mangrove sediments are analyzed as a potential inoculum to form MFC anodes with the use of acetate as substrate. The performance of the EAB-coated carbon cloth electrodes are evaluated according to the maximal current density, the coulombic efficiency and the cyclic voltammogramms. Working electrodes (WE) polarized at -0.2V/SCE gave better results compared to -0.4V/SCE and 0.0V/SCE. The maximal current density attained was 12A/m 2 with a CE of 24%. Contributions of the EAB in the generation of current were discussed and mechanisms of electronic transfer by the bacteria were discussed. Epifluorescence and SEM images showed the evolution of the biofilms on the electrode surface and the heterogeneity of the structure. © 2012 Elsevier Ltd. |
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Laboratoire des Matériaux et des Molécules en Milieu Amazonien, Université des Antilles et de la Guyane, UAG-UMR ECOFOG, F-97337 Cayenne, French Guiana |
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09608524 (Issn) |
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Export Date: 16 August 2012; Source: Scopus; Coden: Birte; doi: 10.1016/j.biortech.2012.05.131; Language of Original Document: English; Correspondence Address: Robert, F.; Laboratoire des Matériaux et des Molécules en Milieu Amazonien, Université des Antilles et de la Guyane, UAG-UMR ECOFOG, F-97337 Cayenne, French Guiana; email: florent.robert@guyane.univ-ag.fr |
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EcoFoG @ webmaster @ |
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421 |
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Siebicke, L.; Hunner, M.; Foken, T. |
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Aspects of CO 2 advection measurements |
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2012 |
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Theoretical and Applied Climatology |
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Theor. Appl. Climatol. |
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109 |
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1-2 |
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109-131 |
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Observations of vegetation-atmosphere exchange of carbon dioxide (CO 2) by the eddy covariance (EC) technique are limited by difficult conditions such as nighttime and heterogeneous terrain. Thus, advective flux components are included into the net ecosystem exchange (NEE) budget. However, advection measurements are experimentally challenging and do not always help to solve the night flux problem of the EC technique. This study investigates alternative methods for the observation of horizontal advection, in particular horizontal concentration gradients, as well as different approaches to coordinate rotation and vertical advection. Continuous high-frequency measurements of the horizontal CO 2 concentration field are employed and compared to the often used discontinuous sequential sampling. Significant differences were found in the case of 30-min mean concentration values between the conventional discontinuous sampling approach and the complete observation of the time series by continuous sampling. Estimates of vertical advection rely on accurate estimates of vertical wind velocity (W). Therefore, different approaches to the planar fit coordinate rotation have been investigated. Sector-wise rotation was able to eliminate directional dependencies of mean W. Furthermore, the effect of the data set length used for rotation (window length) was investigated and was found to have significant impact on estimates of vertical advection, with larger window lengths yielding about 50% larger vertical advection. A sequential planar fit with controlled window length is proposed to give reproducible results. The different approaches to the measurement and calculation of horizontal and vertical advection presented are applied to data obtained during the exchange processes in mountainous region experiment at the FLUXNET site Waldstein-Weidenbrunnen (DE-Bay). Estimates of NEE including advection are compared to NEE from turbulent and storage flux alone without advection. NEE including vertical advection with sector-wise planar fit rotation and controlled window length and including horizontal advection from continuous gradient measurements, which were comprehensively bias corrected by a new approach, did compare well with the expected night flux error, with meteorological drivers of the fluxes and with soil chamber measurements. Unrealistically large and noisy values of horizontal advection from the conventional discontinuous sampling approach, which lead to unrealistic values of NEE, could be eliminated by the alternative approaches presented. We therefore suggest the further testing of those approaches at other sites in order to improve the accuracy of advection measurements and, subsequently, estimates of NEE. © 2011 Springer-Verlag. |
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Wind Cert Services, TÜV SÜD Industrie Service GmbH, Ludwig-Eckert-Str. 10, 93049 Regensburg, Germany |
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Export Date: 27 June 2012; Source: Scopus; doi: 10.1007/s00704-011-0552-3; Language of Original Document: English; Correspondence Address: Siebicke, L.; Department of Micrometeorology, University of Bayreuth, Universitätsstr. 30, 95440 Bayreuth, Germany; email: lukas.siebicke@uni-bayreuth.de |
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406 |
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Coq, S.; Weigel, J.; Bonal, D.; Hattenschwiler, S. |
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Litter mixture effects on tropical tree seedling growth – a greenhouse experiment |
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2012 |
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Plant Biology |
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Plant Biol. |
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14 |
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4 |
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630-640 |
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Amazonian lowland rain forest; Autotoxicity; Belowground/aboveground interactions; Litter decomposition; Plant nutrition; Plant-soil feedback |
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Decomposing litter provides critical nutrients for plants, particularly in nutrient-poor ecosystems such as tropical forests. We hypothesised that decomposing litter improves the performance of a variety of tropical tree seedlings, and that this litter effect varies depending on the species of litter present in litter mixtures. We addressed these hypotheses with a large pot experiment manipulating a range of different litter mixtures of contrasting quality and using seedlings of four tree species from the Amazonian forest of French Guiana. In contrast to our initial hypothesis, decomposing litter had either neutral or negative impacts on seedling growth, despite strongly different growth rates, biomass allocation patterns and leaf and root traits among tree species. Tree species varied in their responses to litter additions, which were further modified by species identity of the added litter. Our data show litter species-specific effects on growth, biomass allocation and leaf and root traits of tropical tree seedlings. These results suggest that a net nutrient release from decomposing litter does not necessarily improve tree seedling growth, even under nutrient-limiting conditions. In conclusion, litter layer composition may affect seedling establishment and recruitment success beyond litter-derived plant nutrient availability, which may contribute to tree species composition and dynamics in the studied tropical forest. © 2012 German Botanical Society and The Royal Botanical Society of the Netherlands. |
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INRA, UMR, Écologie et Écophysiologie, Champenoux, France |
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14358603 (Issn) |
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Export Date: 27 June 2012; Source: Scopus; Coden: Pbiof; doi: 10.1111/j.1438-8677.2011.00534.x; Language of Original Document: English; Correspondence Address: Coq, S.; Laboratoire d'Ecologie Alpine (LECA), CNRS, Université Joseph Fourier, BP 53, F-38042 Grenoble, Cedex 09, France; email: sylvain.coq@gmail.com |
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EcoFoG @ webmaster @ |
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407 |
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Tritsch, I.; Gond, V.; Oszwald, J.; Davy, D.; Grenand, P. |
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Territorial dynamics in the wayãpi and teko amerindian communities of the middle oyapock, camopi, French Guiana |
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Journal Article |
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2012 |
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Bois et Forets des Tropiques |
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Bois Forets Tropiques |
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66 |
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311 |
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49-61 |
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Amerindian populations; French Guiana; Protected area; Slash-and-burn cultivation; System of natural resource use; Territorial management |
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Amerindian populations have been experiencing major socio-economic changes for several decades, in a context of rapid demographic growth. This article addresses the ways in which the Amerindian populations of French Guiana have adapted their land use and natural resource management systems to cope with the pressures exerted on their lands and lifestyles. The aim was to investigate the resilience of their systems for land and natural resource use. The concentration of Amerindian habitats around the town of Camopi, which is linked to the availability of health and school infrastructure and to efforts to promote a sedentary lifestyle, is a factor of increasing natural resource scarcity and social alienation. The system is adapting by fragmenting the Amerindian habitat into peripheral villages and extending farmlands along rivers to access to more space. These villages replicate patterns of spatial organisation that are similar to those found in traditional Wayãpi and Teko villages, except that habitation is sedentary, as families hope to have their villages equipped with at lEast drinking water and electrification. Habitat fragmentation is spatially limited by the time taken for daily journeys to school, and therefore by school bus services (dugout), which means that land use is effectively conditioned by services and infrasrtucture. Other living quarters are maintained at a distance from the village, so that the habitat is bi-local: families have a main home where services and infrastructure are available, and a secondary itinerant home further away, which is chosen according to the quality of farmland, the hunting yield of hunting resources, the history of the location and family networks. These distant homes are kept up by spending income from social assistance on transport. It's thus shown that these Amerindian systems for land and natural resource uses are highly adaptable, in that their sustainability is guaranteed by the reconstruction of a circular pattern of mobility in accordance with the intensity of resource use. |
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Ird Observatoire Hommes-Milieux Oyapock, Cnrs Guyane, 2, avenue Gustave Charlery, 97300 Cayenne, France |
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Export Date: 17 April 2013; Source: Scopus; Language of Original Document: French; Correspondence Address: Tritsch, I.; Université des Antilles et de la Guyane/Cirad, Umr Écologie des forêts de Guyane, Campus agronomique de Kourou, 97310 Kourou, France |
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McLean, J.P.; Arnould, O.; Beauchene, J.; Clair, B. |
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The effect of the G-layer on the viscoelastic properties of tropical hardwoods |
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2012 |
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Annals of Forest Science |
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Ann. Forest Sci. |
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69 |
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3 |
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399-408 |
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Dma; G-layer; Reaction wood; Tropical wood; Viscoelasticity |
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· Context and aim This study aimed to examine the effect of the tension wood G-layer on the viscoelastic properties of wood. · Methods Tension wood and opposite wood samples were obtained from six French Guianese tropical rainforest species (Sextonia rubra, Ocotea guyanensis, Inga alba, Tachigali melinoni, Iyranthera sagotiana and Virola michelii); the tension wood of the former three of these species had a Glayer, whilst the tension wood from the latter three had no Glayer. Tensile dynamic mechanical analysis (DMA) was performed on green never dried wood samples in the longitudinal direction with samples submerged in a water bath at a temperature (30°C) and frequency (1 Hz) representative of the conditions experienced by wood within a living tree. Then, DMA was repeated with samples conditioned to an air-dried state. Finally, samples were oven-dried to measure longitudinal shrinkage. · Results Tension wood did not always have a higher longitudinal storage (elastic) modulus than opposite wood from the same tree regardless of the presence or absence of a G-layer. For the species containing a G-layer, tension wood had a higher damping coefficient and experienced a greater longitudinal shrinkage upon drying than opposite wood from the same species. No difference was found in damping coefficients between tension wood and opposite wood for the species that had no G-layer. · Conclusion It is proposed that the different molecular composition of the G-layer matrix has an influence on the viscoelasticity of wood, even if a biomechanical gain is not yet clear. This study shows that rheological properties and longitudinal shrinkage can be used to detect the presence of a G-layer in tension wood. © INRA/Springer-Verlag France 2011. |
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UMR Ecologie des Forêts de Guyane (ECOFOG), CIRAD, Kourou, French Guiana |
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Export Date: 20 June 2012; Source: Scopus; Coden: Afosf; doi: 10.1007/s13595-011-0164-1; Language of Original Document: English; Correspondence Address: McLean, J.P.; Forest Products Research Institute, Edinburgh Napier University, Merchiston Campus, Edinburgh EH10 5DT, United Kingdom; email: p.mclean@napier.ac.uk |
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