toggle visibility Search & Display Options

Select All    Deselect All
 |   | 
Details
   print
  Records Links
Author Hérault, B.; Piponiot, C. pdf  url
doi  openurl
  Title Key drivers of ecosystem recovery after disturbance in a neotropical forest: Long-term lessons from the Paracou experiment, French Guiana Type Journal Article
  Year 2018 Publication Forest Ecosystems Abbreviated Journal Forest Ecosystems  
  Volume 5 Issue 2 Pages  
  Keywords Amazonia; Carbon fluxes; Climate change; Ecological resilience; Ecosystem modeling; Tropical forests  
  Abstract Background: Natural disturbance is a fundamental component of the functioning of tropical rainforests let to natural dynamics, with tree mortality the driving force of forest renewal. With ongoing global (i.e. land-use and climate) changes, tropical forests are currently facing deep and rapid modifications in disturbance regimes that may hamper their recovering capacity so that developing robust predictive model able to predict ecosystem resilience and recovery becomes of primary importance for decision-making: (i) Do regenerating forests recover faster than mature forests given the same level of disturbance? (ii) Is the local topography an important predictor of the post-disturbance forest trajectories? (iii) Is the community functional composition, assessed with community weighted-mean functional traits, a good predictor of carbon stock recovery? (iv) How important is the climate stress (seasonal drought and/or soil water saturation) in shaping the recovery trajectory? Methods: Paracou is a large scale forest disturbance experiment set up in 1984 with nine 6.25 ha plots spanning on a large disturbance gradient where 15 to 60% of the initial forest ecosystem biomass were removed. More than 70,000 trees belonging to ca. 700 tree species have then been censused every 2 years up today. Using this unique dataset, we aim at deciphering the endogenous (forest structure and composition) and exogenous (local environment and climate stress) drivers of ecosystem recovery in time. To do so, we disentangle carbon recovery into demographic processes (recruitment, growth, mortality fluxes) and cohorts (recruited trees, survivors). Results: Variations in the pre-disturbance forest structure or in local environment do not shape significantly the ecosystem recovery rates. Variations in the pre-disturbance forest composition and in the post-disturbance climate significantly change the forest recovery trajectory. Pioneer-rich forests have slower recovery rates than assemblages of late-successional species. Soil water saturation during the wet season strongly impedes ecosystem recovery but not seasonal drought. From a sensitivity analysis, we highlight the pre-disturbance forest composition and the post-disturbance climate conditions as the primary factors controlling the recovery trajectory. Conclusions: Highly-disturbed forests and secondary forests because they are composed of a lot of pioneer species will be less able to cope with new disturbance. In the context of increasing tree mortality due to both (i) severe droughts imputable to climate change and (ii) human-induced perturbations, tropical forest management should focus on reducing disturbances by developing Reduced Impact Logging techniques.  
  Address (down) Université de la Guyane, UMR EcoFoG (AgroParistech, Cirad, CNRS, Inra, Université des Antilles), Campus Agronomique, Kourou, French Guiana, 97310, France  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Cited By :1; Export Date: 1 September 2018 Approved no  
  Call Number EcoFoG @ webmaster @ Serial 812  
Permanent link to this record
 

 
Author Dézerald, O.; Leroy, C.; Corbara, B.; Dejean, A.; Talaga, S.; Céréghino, R. url  doi
openurl 
  Title Tank bromeliads sustain high secondary production in neotropical forests Type Journal Article
  Year 2018 Publication Aquatic Sciences Abbreviated Journal  
  Volume 80 Issue 14 Pages  
  Keywords Biomass turnover; Epiphytes; Food webs; Functional traits; Invertebrates; Rainforests  
  Abstract In neotropical landscapes, a substantial fraction of the still waters available is found within tank bromeliads, plants which hold a few milliliters to several litres of rainwater within their leaf axils. The bromeliad ecosystem is integrated into the functioning of rainforest environments, but no study has ever estimated the secondary production, nor the biomass turnover rates of bromeliad macroinvertebrates in relation to other functional traits. We estimated secondary production at invertebrate population to metacommunity level in bromeliads of French Guiana. Coleoptera, Diptera and Crustacea with traits that confer resistance to drought had lower biomass turnover, longer generation times, and slower individual growth than species without particular resistance traits, suggesting convergent life history strategies in phylogenetically distant species. Detritivores and predators accounted for 87% and 13% of the overall annual production, respectively, but had similar production to biomass ratios. An average bromeliad sustained a production of 23.93 g dry mass m−2 year−1, a value which exceeds the medians of 5.0–14.8 g DM m−2 year−1 for lakes and rivers worldwide. Extrapolations to the total water volumes held by bromeliads at our field site yielded secondary production estimates of 226.8 ± 32.5 g DM ha−1 year−1. We conclude that the ecological role of tank bromeliads in neotropical rainforests may be as important as that of other freshwater ecosystems. © 2018, Springer International Publishing AG, part of Springer Nature.  
  Address (down) Université de Guyane, UMR Écologie des Forêts de Guyane (AgroParisTech, CIRAD, CNRS, INRA, Université des Antilles), Campus Agronomique, BP 316, Kourou cedex, France  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Export Date: 29 January 2018 Approved no  
  Call Number EcoFoG @ webmaster @ Serial 790  
Permanent link to this record
 

 
Author Dejean, A.; Céréghino, R.; Leponce, M.; Rossi, V.; Roux, O.; Compin, A.; Delabie, J.H.C.; Corbara, B. url  openurl
  Title The fire ant Solenopsis saevissima and habitat disturbance alter ant communities Type Journal Article
  Year 2015 Publication Biological Conservation Abbreviated Journal Biological Conservation  
  Volume 187 Issue Pages 145-153  
  Keywords Ant community; Fire ants; Invasive species; Species coexistence; Supercoloniality  
  Abstract The fire ant Solenopsis saevissima is a major pest frequent in human-disturbed areas of its native range where it forms 'supercolonies'. We determined that its natural habitat in French Guiana is likely the sporadically flooded riparian forest and aimed to evaluate this ant's impact on the abundance and diversity of other ants by comparing different habitats at two sites. We noted a significant decrease in ant species richness between the rainforest and human-disturbed habitats (but not between the former and the naturally disturbed riparian forest), and between extreme habitats and all others. The number of ant nests per surface unit (i.e., quadrats of equal surface area), a proxy of ant abundance, globally followed this pattern. S. saevissima was absent from pristine rainforest (as expected) and from extreme habitats, showing the limits of its adaptability, whereas some other native ants can develop in these habitats. Ant species richness was significantly lower in the presence of S. saevissima in the riparian forest, forest edges and meadows, illustrating that this ant species has a negative impact on the ant communities in addition to the impact of natural- and man-made disturbances. Only some ant species can develop in its presence, and certain of these can even thrive. Because it has been recorded in Africa, Guadeloupe and the Galápagos Islands, we concluded that, due to the increasing volume of global trade and forest destruction, S. saevissima could become a pantropical invasive species. © 2015 Elsevier Ltd.  
  Address (down) Université Clermont Auvergne, Université Blaise Pascal (LMGE), Clermont-Ferrand, France  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Export Date: 11 June 2015 Approved no  
  Call Number EcoFoG @ webmaster @ Serial 605  
Permanent link to this record
 

 
Author Dejean, A.; Ryder, S.; Bolton, B.; Compin, A.; Leponce, M.; Azémar, F.; Céréghino, R.; Orivel, J.; Corbara, B. url  openurl
  Title How territoriality and host-tree taxa determine the structure of ant mosaics Type Journal Article
  Year 2015 Publication The Science of Nature Abbreviated Journal Sci Nat  
  Volume 102 Issue 33 Pages 1-9  
  Keywords Africa; Arboreal ants; Distribution; Host-tree selection; Rainforest canopies  
  Abstract Very large colonies of territorially dominant arboreal ants (TDAAs), whose territories are distributed in a mosaic pattern in the canopies of many tropical rainforests and tree crop plantations, have a generally positive impact on their host trees. We studied the canopy of an old Gabonese rainforest (ca 4.25 ha sampled, corresponding to 206 Blarge trees) at a stage just preceding forest maturity (the Caesalpinioideae dominated; the Burseraceae were abundant). The tree crowns sheltered colonies from 13 TDAAs plus a codominant species out of the 25 ant species recorded. By mapping the TDAAs' territories and using a null model cooccurrence analysis, we confirmed the existence of an ant mosaic. Thanks to a large sampling set and the use of the self-organizing map algorithm (SOM), we show that the distribution of the trees influences the structure of the ant mosaic, suggesting that each tree taxon attracts certain TDAA species rather than others. The SOMalso improved our knowledge of the TDAAs' ecological niches, showing that these ant species are ecologically distinct from each other based on their relationships with their supporting trees. Therefore, TDAAs should not systematically be placed in the same functional group even when they belong to the same genus.We conclude by reiterating that, in addition to the role played by TDAAs' territorial competition, host trees contribute to structuring ant mosaics through multiple factors, including host-plant selection by TDAAs, the age of the trees, the presence of extrafloral nectaries, and the taxa of the associated hemipterans. © Springer-Verlag Berlin Heidelberg 2015.  
  Address (down) Université Clermont Auvergne, Université Blaise Pascal (LMGE), Clermont-Ferrand, France  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Export Date: 16 October 2015 Approved no  
  Call Number EcoFoG @ webmaster @ Serial 632  
Permanent link to this record
 

 
Author Dejean, A.; Orivel, J.; Azémar, F.; Herault, B.; Corbara, B. pdf  url
doi  openurl
  Title A cuckoo-like parasitic moth leads African weaver ant colonies to their ruin Type Journal Article
  Year 2016 Publication Scientific Reports Abbreviated Journal Sci. Rep.  
  Volume 6 Issue Pages 23778  
  Keywords  
  Abstract In myrmecophilous Lepidoptera, mostly lycaenids and riodinids, caterpillars trick ants into transporting them to the ant nest where they feed on the brood or, in the more derived 'cuckoo strategy', trigger regurgitations (trophallaxis) from the ants and obtain trophic eggs. We show for the first time that the caterpillars of a moth (Eublemma albifascia; Noctuidae; Acontiinae) also use this strategy to obtain regurgitations and trophic eggs from ants (Oecophylla longinoda). Females short-circuit the adoption process by laying eggs directly on the ant nests, and workers carry just-hatched caterpillars inside. Parasitized colonies sheltered 44 to 359 caterpillars, each receiving more trophallaxis and trophic eggs than control queens. The thus-starved queens lose weight, stop laying eggs (which transport the pheromones that induce infertility in the workers) and die. Consequently, the workers lay male-destined eggs before and after the queen's death, allowing the colony to invest its remaining resources in male production before it vanishes.  
  Address (down) Université Clermont Auvergne, Université Blaise Pascal (LMGE), Clermont-Ferrand, France  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Export Date: 22 April 2016 Approved no  
  Call Number EcoFoG @ webmaster @ Serial 674  
Permanent link to this record
 

 
Author Traissac, S.; Pascal, J.-P. url  openurl
  Title Birth and life of tree aggregates in tropical forest: Hypotheses on population dynamics of an aggregated shade-tolerant species Type Journal Article
  Year 2014 Publication Journal of Vegetation Science Abbreviated Journal J. Veg. Sci.  
  Volume 25 Issue 2 Pages 491-502  
  Keywords Clusters; Colonization strategy; Janzen-Connell; Spatial analysis; Spatial pattern; Vouacapoua americana  
  Abstract Questions: Several studies have described aggregated spatial patterns in tropical tree species. This study investigates aggregate dynamics of Vouacapoua americana (Aublet), a climax species whose spatial pattern is not simply related to light and soil conditions or to its short seed dispersal range. Location: Two rain forest sites: Nouragues and Paracou, in the Guiana Shield. Methods: We described the spatial pattern of tree locations and spatial autocorrelation of tree diameters, using statistics derived from Ripley's K. We particularly used methods to define analysis subplots according to local density or local mean diameter. We investigated relationships between spatial distributions of adults and saplings. Results: At both sites, populations of Vouacapoua demonstrated several nested levels of aggregation. Tree diameters were spatially autocorrelated, revealing the existence of clusters with similar diameters. In the largest aggregates, tree diameters declined from the centre to the edge. Regeneration was aggregated and occurred mainly at cluster edges and around rare isolated trees, and sapling densities and basal area of adults were negatively correlated. We show that long-distance dispersal events are rare. Conclusions: Environmental factors and seed dispersal only explain part of the observed spatial patterns. We provide two main hypotheses about Vouacapoua population dynamics. First, the lack of regeneration in aggregate centres results in the ageing of existing aggregates. We suggest that this lack of recruitment close to mature trees is due to a Janzen-Connell effect. However, aggregates can continue to grow along colonization fronts. Second, long-distance dispersal events allow the formation of new clusters and play a crucial role in the colonization process. We investigate aggregate dynamics of Vouacapoua americana (Aublet) whose spatial pattern is not simply related to environmental conditions or to its seed dispersal. Regeneration does not occur in centers of aggregate of adults. We suggest that rare long-distance dispersal events and density-dependence predation of seeds and seedlings play a crucial role in formation of new clusters and structuration of larger aggregates. © 2013 International Association for Vegetation Science.  
  Address (down) Université Claude Bernard Lyon 1, 43 Boulevard 11 Novembre 1918, Villeurbanne, 69100, France  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 11009233 (Issn) ISBN Medium  
  Area Expedition Conference  
  Notes Export Date: 10 March 2014; Source: Scopus; Coden: Jvese; Language of Original Document: English; Correspondence Address: Traissac, S.; AgroParisTech, UMR ECOlogie des Forêts de Guyane, Campus Agronomique, BP 709, Kourou, 97387, France; email: stephane.traissac@ecofog.gf Approved no  
  Call Number EcoFoG @ webmaster @ Serial 532  
Permanent link to this record
 

 
Author Sist, P.; Blanc, L.; Mazzei, L.; Baraloto, C.; Aussenac, R. url  openurl
  Title Current knowledge on overall post-logging biomass dynamics in Northern Amazonian forests Type Journal Article
  Year 2012 Publication Bois et Forets des Tropiques Abbreviated Journal Bois Forets Tropiques  
  Volume 66 Issue 314 Pages 41-49  
  Keywords Above ground-biomass; Amazonian rainforests; Logging impact; Silviculture  
  Abstract This article presents the effects of logging on the dynamics of above-ground biomass from the results of the post-logging study within two forests: Cikel in Eastern Pará, Brazil and Paracou in French Guiana. The main objective is to compare the impact of commercial logging on the regeneration of the aboveground biomass in these forests whose characteristics differ in terms of structure and growth. In both sites, the intensity of exploitation is a key factor in determining the loss of biomass and the time required for its regeneration. In Paracou, the regeneration of biomass lost during conventional logging of 10 trees per hectare takes 45 years and more than 100 years when operating with higher intensity (21 trees/ha ). In Cikel the forest biomass regenerates after 49 years harvesting 6 trees/ha and that takes 87 years after removal of 8 trees/ha. This regeneration needs similar time on both sites but with lower logging intensity at Cikel, in which felled trees are larger with a greater biomass than those of Paracou. This post-logging study has established a direct correlation of the dynamics of the biomass with the initial structure of the forest, as well as with the parameters of forest dynamics: mortality, growth and recruitment. The accumulation of biomass by the tree growth of the two remaining stands is a key parameter for the net carbon storage, while the contribution of recruitment in Paracou becomes significant only after 10 years after felling. Therefore in view to improve the growth of residual trees, it is compulsory to apply adequate silvicultural treatments such as selective thinning or removal of vines. While the two forests are geographically close enough, their regenerative abilities differ and because of the significant difference in size of the trees, the forest could tolerate more intensive harvesting in French Guiana.  
  Address (down) Université Antilles-Guyane Cayenne, Guyane, France  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0006579x (Issn) ISBN Medium  
  Area Expedition Conference  
  Notes Export Date: 5 June 2013; Source: Scopus; Language of Original Document: English; Correspondence Address: Cirad UR B and SEF, Campus international de Baillarguet, 34398 Montpellier Cedex 5, France Approved no  
  Call Number EcoFoG @ webmaster @ Serial 489  
Permanent link to this record
 

 
Author Bastias, C.C.; Fortunel, C.; Valladares, F.; Baraloto, C.; Benavides, R.; Cornwell, W.; Markesteijn, L.; De Oliveira, A.A.; Sansevero, J.B.B.; Vaz, M.C.; Kraft, N.J.B. pdf  url
doi  openurl
  Title Intraspecific leaf trait variability along a boreal-to-tropical community diversity gradient Type Journal Article
  Year 2017 Publication PLoS ONE Abbreviated Journal PLoS ONE  
  Volume 12 Issue 2 Pages e0172495  
  Keywords  
  Abstract Disentangling the mechanisms that shape community assembly across diversity gradients is a central matter in ecology. While many studies have explored community assembly through species average trait values, there is a growing understanding that intraspecific trait variation (ITV) can also play a critical role in species coexistence. Classic biodiversity theory hypothesizes that higher diversity at species-rich sites can arise from narrower niches relative to species-poor sites, which would be reflected in reduced ITV as species richness increases. To explore how ITV in woody plant communities changes with species richness, we compiled leaf trait data (leaf size and specific leaf area) in a total of 521 woody plant species from 21 forest communities that differed dramatically in species richness, ranging from boreal to tropical rainforests. At each forest, we assessed ITV as an estimate of species niche breadth and we quantified the degree of trait overlap among co-occurring species as a measure of species functional similarity. We found ITV was relatively invariant across the species richness gradient. In addition, we found that species functional similarity increased with diversity. Contrary to the expectation from classic biodiversity theory, our results rather suggest that neutral processes or equalizing mechanisms can be acting as potential drivers shaping community assembly in hyperdiverse forests. © This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.  
  Address (down) Universidade Federal Rural do Rio de Janeiro-UFRRJ, Departamento de Ciencias Ambientais-DCA, Instituto de Florestas, Seropédica, Rio de Janeiro, Brazil  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Export Date: 13 March 2017 Approved no  
  Call Number EcoFoG @ webmaster @ Serial 744  
Permanent link to this record
 

 
Author Honorio Coronado, E.N.; Dexter, K.G.; Pennington, R.T.; Chave, J.; Lewis, S.L.; Alexiades, M.N.; Alvarez, E.; Alves de Oliveira, A.; Amaral, I.L.; Araujo-Murakami, A.; Arets, E.J.M.M.; Aymard, G.A.; Baraloto, C.; Bonal, D.; Brienen, R.; Cerón, C.; Cornejo Valverde, F.; Di Fiore, A.; Farfan-Rios, W.; Feldpausch, T.R.; Higuchi, N.; Huamantupa-Chuquimaco, I.; Laurance, S.G.; Laurance, W.F.; López-Gonzalez, G.; Marimon, B.S.; Marimon-Junior, B.H.; Monteagudo Mendoza, A.; Neill, D.; Palacios Cuenca, W.; Peñuela Mora, M.C.; Pitman, N.C.A.; Prieto, A.; Quesada, C.A.; Ramirez Angulo, H.; Rudas, A.; Ruschel, A.R.; Salinas Revilla, N.; Salomão, R.P.; Segalin de Andrade, A.; Silman, M.R.; Spironello, W.; ter Steege, H.; Terborgh, J.; Toledo, M.; Valenzuela Gamarra, L.; Vieira, I.C.G.; Vilanova Torre, E.; Vos, V.; Phillips, O.L. url  openurl
  Title Phylogenetic diversity of Amazonian tree communities Type Journal Article
  Year 2015 Publication Diversity and Distributions Abbreviated Journal Diversity and Distributions  
  Volume 21 Issue 11 Pages 1295-1307  
  Keywords Amazon basin; Eudicots; Magnoliids; Monocots; Phylogenetic diversity; Species richness  
  Abstract Aim: To examine variation in the phylogenetic diversity (PD) of tree communities across geographical and environmental gradients in Amazonia. Location: Two hundred and eighty-three c. 1 ha forest inventory plots from across Amazonia. Methods: We evaluated PD as the total phylogenetic branch length across species in each plot (PDss), the mean pairwise phylogenetic distance between species (MPD), the mean nearest taxon distance (MNTD) and their equivalents standardized for species richness (ses.PDss, ses.MPD, ses.MNTD). We compared PD of tree communities growing (1) on substrates of varying geological age; and (2) in environments with varying ecophysiological barriers to growth and survival. Results: PDss is strongly positively correlated with species richness (SR), whereas MNTD has a negative correlation. Communities on geologically young- and intermediate-aged substrates (western and central Amazonia respectively) have the highest SR, and therefore the highest PDss and the lowest MNTD. We find that the youngest and oldest substrates (the latter on the Brazilian and Guiana Shields) have the highest ses.PDss and ses.MNTD. MPD and ses.MPD are strongly correlated with how evenly taxa are distributed among the three principal angiosperm clades and are both highest in western Amazonia. Meanwhile, seasonally dry tropical forest (SDTF) and forests on white sands have low PD, as evaluated by any metric. Main conclusions: High ses.PDss and ses.MNTD reflect greater lineage diversity in communities. We suggest that high ses.PDss and ses.MNTD in western Amazonia results from its favourable, easy-to-colonize environment, whereas high values in the Brazilian and Guianan Shields may be due to accumulation of lineages over a longer period of time. White-sand forests and SDTF are dominated by close relatives from fewer lineages, perhaps reflecting ecophysiological barriers that are difficult to surmount evolutionarily. Because MPD and ses.MPD do not reflect lineage diversity per se, we suggest that PDss, ses.PDss and ses.MNTD may be the most useful diversity metrics for setting large-scale conservation priorities. © 2015 John Wiley & Sons Ltd.  
  Address (down) Universidad Autónoma del Beni, Av. Ejército Nacional, Riberalta, Riberalta, Bolivia  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Export Date: 22 October 2015 Approved no  
  Call Number EcoFoG @ webmaster @ Serial 634  
Permanent link to this record
 

 
Author Levionnois, S.; Ziegler, C.; Jansen, S.; Calvet, E.; Coste, S.; Stahl, C.; Salmon, C.; Delzon, S.; Guichard, C.; Heuret, P. doi  openurl
  Title Vulnerability and hydraulic segmentations at the stem–leaf transition: coordination across Neotropical trees Type Journal Article
  Year 2020 Publication New Phytologist Abbreviated Journal New Phytol.  
  Volume 228 Issue 2 Pages 512-524  
  Keywords drought-induced embolism resistance; hydraulic segmentation; leaf-specific conductivity; stem–leaf transition; tropical trees; vulnerability segmentation; air bubble; hydraulic conductivity; leaf; Neotropical Region; rainforest; tropical forest; vulnerability; xylem  
  Abstract Hydraulic segmentation at the stem–leaf transition predicts higher hydraulic resistance in leaves than in stems. Vulnerability segmentation, however, predicts lower embolism resistance in leaves. Both mechanisms should theoretically favour runaway embolism in leaves to preserve expensive organs such as stems, and should be tested for any potential coordination. We investigated the theoretical leaf-specific conductivity based on an anatomical approach to quantify the degree of hydraulic segmentation across 21 tropical rainforest tree species. Xylem resistance to embolism in stems (flow-centrifugation technique) and leaves (optical visualization method) was quantified to assess vulnerability segmentation. We found a pervasive hydraulic segmentation across species, but with a strong variability in the degree of segmentation. Despite a clear continuum in the degree of vulnerability segmentation, eight species showed a positive vulnerability segmentation (leaves less resistant to embolism than stems), whereas the remaining species studied exhibited a negative or no vulnerability segmentation. The degree of vulnerability segmentation was positively related to the degree of hydraulic segmentation, such that segmented species promote both mechanisms to hydraulically decouple leaf xylem from stem xylem. To what extent hydraulic and vulnerability segmentation determine drought resistance requires further integration of the leaf–stem transition at the whole-plant level, including both xylem and outer xylem tissue. © 2020 The Authors. New Phytologist © 2020 New Phytologist Trust  
  Address (down) Univ. Bordeaux, INRAE, BIOGECO, Pessac, F-33615, France  
  Corporate Author Thesis  
  Publisher Blackwell Publishing Ltd Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0028646x (Issn) ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number EcoFoG @ webmaster @ Serial 952  
Permanent link to this record
Select All    Deselect All
 |   | 
Details
   print

Save Citations:
Export Records: