| Records |
Author  |
Vincent, G.; Weissenbacher, E.; Sabatier, D.; Blanc, L.; Proisy, C.; Couteron, P. |
| Title |
Detection des variations de structure de peuplements en foret dense tropicale humide par lidar aeroporte |
Type |
Journal Article |
| Year |
2010 |
Publication |
Revue Francaise de Photogrammetrie et de Teledetection |
Abbreviated Journal |
Rev. Fr. Photogramm. Teledetect. |
| Volume |
191 |
Issue |
|
Pages |
42-51 |
| Keywords |
Above-ground biomass estimation; Canopy height model; Stem diameter distribution; Tropical moist forest; Above ground biomass; Above ground level; Airborne LiDAR; Basal area; Canopy Height Models; Carbon stocks; Characterisation; Classical fields; Coefficient of variation; Diameter distributions; Digital terrain model; Flooded areas; Forest ecology; Forest structure; Forest type; High spatial resolution; Individual tree; LIDAR data; Light detection and ranging; Local statistics; Long term; Management issues; Natural forests; Natural variation; Pearson correlation coefficients; Quadratic mean diameter; Soil characteristics; Soil cover; Spatial changes; Spatial resolution; Stem density; Stem diameter; Stem height; Strong correlation; Tree height; Tropical moist forest; Tropical rain forest; Vegetation structure; Vertical accuracy; Water regime; Discriminant analysis; Ecology; Optical radar; Remote sensing; Soils; Statistics; Stem cells; Temperature control; Tropics; Vegetation; Forestry; Biomass; Discriminant Analysis; Ecology; Forest Canopy; Forestry; Radar; Remote Sensing; Stems; Temperature Control; Tropical Atmospheres |
| Abstract |
Characterisation of forest structure is a major stake for forestry, species conservation, carbon stock estimates and many forest ecology and management issues. At large scale natural forest structure tends to vary according to climate and geomorphomology (Paget, 1999; Steege et al., 2006) while soil characteristics (and notably water regime) and syMgenetic stage add some finer scale variation (Oldeman, 1989; Sabatier et al., 1997). Forest structure characterisation traditionally relies on field-based collection of individual tree dimensions such as stem diameter and stem height sampled across tracks of forest (Hall et al., 1998). However, such field intensive methods are costly, and of low accuracy regarding measures of tree heights. Airborne light detection and ranging (LiDAR) technology provides horizontal and vertical Information at high spatial resolutions and vertical accuracies (Lim et al., 2003; Hyyppä et al., 2004). It has the potential for gathering vegetation structure data over large areas rapidly at moderate cost and hence is of particular relevance for poorly sampled, difficult to access and largely unexplored tropical rainforests. In this study we examined the ability of airborne LiDAR to detect spatial changes in the structure of dense tropical rain forest and we probed this remote sensing approach against local statistics derived from stem diameters (i.e. classical field data information) mapped across a large track of forest at a long term experimental site in French Guyana. The large variability in forest structure occurring at the experimental site is du to natural variation of the soil cover (and notably drainage properties) combined with various logging intensities applied 15 years before the LiDAR data were acquired. On this basis ten different forest types were identified at the site (figure 1 and 3). Various stem based statistics were computed for a series of meshes with cells ranging from 30 by 30 m plots to 250 by 250 m plots. These statistics included basal area, stem density, quadratic mean diameter, and diameter distribution percentiles. Similarly local statistics were extracted either from the Canopy Height Model (e.g. median height, mean height, standard height deviation, height coefficient of variation, height percentiles, frequency of hits below 5 m above ground level). Additionally a wetness index (Böhner et al., 2002) was computed at each node of a 5 by 5 m grid from the Digital Terrain Model also extracted from the LiDAR data set. We used both types of cell statistics to discriminate the various forest types. Comparison between the two approaches for a range of spatial resolution is available from in table 1. Results indicate that LiDAR based statistics are essentially as powerful as field based statistics to discriminate forest types at coarse scale. This reflects the very strong correlation between the CHM and the field based stem diameter data. For example (figure 5) the Pearson correlation coefficient between median height and quadratic mean diameter for cells of 125 by 125 m is 0.945 (n=0.72). When a finer resolution is required however as for the detection of seasonally flooded bottomland forest along thalwegs, then LiDAR technology proves more efficient than field based inventories as it combines information from the DTM and the CHM. The wetness index alone correctly retrieves about 2 thirds of the seasonally flooded areas. All in all, discriminant analysis performance of the LiDAR derived information approaches 80% when classifying forests cover at the finest scale of 5 by 5m into 10 different types and reaches 87% when a coarser classification Into 6 forest types is considered (figure 4). |
| Address |
IRD, UMR AMAP, Montpellier, 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 |
17689791 (Issn) |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
Cited By (since 1996): 1; Export Date: 21 October 2011; Source: Scopus; Language of Original Document: French; Correspondence Address: Vincent, G.; IRD, UMR AMAP, Kourou – BP 701 (CIRAD) 97387 Kourou cedex -Guyane, France |
Approved |
no |
| Call Number |
EcoFoG @ webmaster @ |
Serial |
351 |
| Permanent link to this record |
| |
|
| |
| Author |
Vincent, G.; Sabatier, D.; Blanc, L.; Chave, J.; Weissenbacher, E.; Pélissier, R.; Fonty, E.; Molino, J.-F.; Couteron, P. |
| Title |
Accuracy of small footprint airborne LiDAR in its predictions of tropical moist forest stand structure |
Type |
Journal Article |
| Year |
2012 |
Publication |
Remote Sensing of Environment |
Abbreviated Journal |
Remote Sens. Environ. |
| Volume |
125 |
Issue |
|
Pages |
23-33 |
| Keywords |
Basal area; Lidar; Tropical moist forest |
| Abstract |
We predict stand basal area (BA) from small footprint LiDAR data in 129 one-ha tropical forest plots across four sites in French Guiana and encompassing a great diversity of forest structures resulting from natural (soil and geological substrate) and anthropogenic effects (unlogged and logged forests). We use predictors extracted from the Canopy Height Model to compare models of varying complexity: single or multiple regressions and nested models that predict BA by independent estimates of stem density and quadratic mean diameter. Direct multiple regression was the most accurate, giving a 9.6% Root Mean Squared Error of Prediction (RMSEP). The magnitude of the various errors introduced during the data collection stage is evaluated and their contribution to MSEP is analyzed. It was found that these errors accounted for less than 10% of model MSEP, suggesting that there is considerable scope for model improvement. Although site-specific models showed lower MSEP than global models, stratification by site may not be the optimal solution. The key to future improvement would appear to lie in a stratification that captures variations in relations between LiDAR and forest structure. © 2012 Elsevier Inc. |
| Address |
ONF, Direction régionale de la Guyane, Cayenne, 97300 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 |
00344257 (Issn) |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
Export Date: 9 August 2012; Source: Scopus; Article in Press; Coden: Rseea; doi: 10.1016/j.rse.2012.06.019; Language of Original Document: English; Correspondence Address: Vincent, G.; IRD AMAP CIRAD, TA A-51/PS2, 34398 Montpellier cedex 5, Franceemail: gregoire.vincent@ird.fr |
Approved |
no |
| Call Number |
EcoFoG @ webmaster @ |
Serial |
418 |
| Permanent link to this record |
| |
|
| |
| Author |
Vincent, G.; Molino, J.F.; Marescot, L.; Barkaoui, K.; Sabatier, D.; Freycon, V.; Roelens, J.B. |
| Title |
The relative importance of dispersal limitation and habitat preference in shaping spatial distribution of saplings in a tropical moist forest: a case study along a combination of hydromorphic and canopy disturbance gradients |
Type |
Journal Article |
| Year |
2011 |
Publication |
Annals of Forest Science |
Abbreviated Journal |
Ann. For. Sci. |
| Volume |
68 |
Issue |
2 |
Pages |
357-370 |
| Keywords |
Species assemblage; Dispersal limitation; Tropical moist forest; Niche |
| Abstract |
Various processes contribute to shaping the local assemblage of species in hyperdiverse tropical forest. The relative contribution of environmental factors and dispersal limitation in determining the spatial distribution of saplings at local scale is unclear. We examined two types of environmental factors: (a) soil type reflecting drainage regime and (b) past logging damages reflecting light regime in a neotropical moist forest site. We used a logistic model to predict presence or absence of a given species in a network of elementary small plots. The effect of mapped environmental factors and a spatial correlation term were jointly estimated providing a direct measure of the relative role of habitat specialisation and dispersal limitation. At community level, dispersal limitation was the most important determinant of species absence at local scale. The two environmental factors examined played a balanced role. Different species however showed different degrees of dispersal limitation and habitat specialisation. The distribution of a large proportion of species-the majority of the most abundant species-was significantly affected by at least one environmental factor. We provide a ranking of 49 species sensitive to canopy disturbance (from shade specialist to pioneer) and 41 species affected by seasonal flooding (either positively or negatively). |
| Address |
[Vincent, Gregoire; Marescot, Lucile; Barkaoui, Karim] IRD, Unite Mixte Rech AMAP, Kourou 97387, French Guiana, Email: gregoire.vincent@ird.fr |
| Corporate Author |
|
Thesis |
|
| Publisher |
Springer France |
Place of Publication |
|
Editor |
|
| Language |
|
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
1286-4560 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
ISI:000290448000014 |
Approved |
no |
| Call Number |
EcoFoG @ webmaster @ |
Serial |
318 |
| Permanent link to this record |
| |
|
| |
| Author |
Vincent, G.; Caron, F.; Sabatier, D.; Blanc, L. |
| Title |
LiDAR shows that higher forests have more slender trees |
Type |
Journal Article |
| Year |
2012 |
Publication |
Bois et Forets des Tropiques |
Abbreviated Journal |
Bois Forets Tropiques |
| Volume |
66 |
Issue |
314 |
Pages |
51-56 |
| Keywords |
Competition; Fertility; French Guiana; LiDAR; Tree allometry |
| Abstract |
High-density Airborne Laser Scanning was used to derive the Canopy Height Model (CHM) of an experimental forest site in the neotropics (Paracou, French Guiana). Individual tree heights were computed by manually segmenting tree crowns on the CHM and then extracting the local maximum canopy height. Three hundred and ninety-six (396) height estimates were matched from dominant or emergent trees with the corresponding ground records of stem diameters sampled in two plots with different mean canopy heights (28.1 m vs. 31.3 m). Tree slenderness was found to be positively and very significantly correlated with mean canopy height at the plot level. The same correlation was observed at the species population level for the three species adequately sampled. It can therefore be concluded that stratification by canopy height is to be recommended when deriving allometric relationships in order to avoid bias in Above Ground Biomass estimations. |
| Address |
CIRAD, UMR Ecofog, 97300 Kourou, 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: IRD, UMR AMAP, 34000 Montpellier, France |
Approved |
no |
| Call Number |
EcoFoG @ webmaster @ |
Serial |
490 |
| Permanent link to this record |
| |
|
| |
| Author |
Verryckt, L.T.; Van Langenhove, L.; Ciais, P.; Courtois, E.A.; Vicca, S.; Peñuelas, J.; Stahl, C.; Coste, S.; Ellsworth, D.S.; Posada, J.M.; Obersteiner, M.; Chave, J.; Janssens, I.A. |
| Title |
Coping with branch excision when measuring leaf net photosynthetic rates in a lowland tropical forest |
Type |
Journal Article |
| Year |
2020 |
Publication |
Biotropica |
Abbreviated Journal |
Biotropica |
| Volume |
52 |
Issue |
4 |
Pages |
608-615 |
| Keywords |
branch cutting; canopy physiology; French Guiana; gas exchange; photosynthesis; rainforest; stomatal conductance; ecological modeling; environmental conditions; forest canopy; leaf; measurement method; photosynthesis; tree; tropical forest; Gruidae |
| Abstract |
Measuring leaf gas exchange from canopy leaves is fundamental for our understanding of photosynthesis and for a realistic representation of carbon uptake in vegetation models. Since canopy leaves are often difficult to reach, especially in tropical forests with emergent trees up to 60 m at remote places, canopy access techniques such as canopy cranes or towers have facilitated photosynthetic measurements. These structures are expensive and therefore not very common. As an alternative, branches are often cut to enable leaf gas exchange measurements. The effect of branch excision on leaf gas exchange rates should be minimized and quantified to evaluate possible bias. We compared light-saturated leaf net photosynthetic rates measured on excised and intact branches. We selected branches positioned at three canopy positions, estimated relative to the top of the canopy: upper sunlit foliage, middle canopy foliage, and lower canopy foliage. We studied the variation of the effects of branch excision and transport among branches at these different heights in the canopy. After excision and transport, light-saturated leaf net photosynthetic rates were close to zero for most leaves due to stomatal closure. However, when the branch had acclimated to its new environmental conditions—which took on average 20 min—light-saturated leaf net photosynthetic rates did not significantly differ between the excised and intact branches. We therefore conclude that branch excision does not affect the measurement of light-saturated leaf net photosynthesis, provided that the branch is recut under water and is allowed sufficient time to acclimate to its new environmental conditions. © 2020 The Association for Tropical Biology and Conservation |
| Address |
UMR 5174 Laboratoire Evolution et Diversité Biologique, Université Paul Sabatier, CNRS, Toulouse, 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 |
00063606 (Issn) |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
|
Approved |
no |
| Call Number |
EcoFoG @ webmaster @ |
Serial |
960 |
| Permanent link to this record |
| |
|
| |
| Author |
Verryckt, L.T.; Ellsworth, D.S.; Vicca, S.; Van Langenhove, L.; Peñuelas, J.; Ciais, P.; Posada, J.M.; Stahl, C.; Coste, S.; Courtois, E.A.; Obersteiner, M.; Chave, J.; Janssens, I.A. |
| Title |
Can light-saturated photosynthesis in lowland tropical forests be estimated by one light level? |
Type |
Journal Article |
| Year |
2020 |
Publication |
Biotropica |
Abbreviated Journal |
Biotropica |
| Volume |
52 |
Issue |
6 |
Pages |
1183-1193 |
| Keywords |
canopy architecture; interspecific variation; light intensity; lowland environment; parameter estimation; photon flux density; photosynthesis; saturation; tropical forest; French Guiana |
| Abstract |
Leaf-level net photosynthesis (An) estimates and associated photosynthetic parameters are crucial for accurately parameterizing photosynthesis models. For tropical forests, such data are poorly available and collected at variable light conditions. To avoid over- or underestimation of modeled photosynthesis, it is critical to know at which photosynthetic photon flux density (PPFD) photosynthesis becomes light-saturated. We studied the dependence of An on PPFD in two tropical forests in French Guiana. We estimated the light saturation range, including the lowest PPFD level at which Asat (An at light saturation) is reached, as well as the PPFD range at which Asat remained unaltered. The light saturation range was derived from photosynthetic light-response curves, and within-canopy and interspecific differences were studied. We observed wide light saturation ranges of An. Light saturation ranges differed among canopy heights, but a PPFD level of 1,000 µmol m−2 s−1 was common across all heights, except for pioneer trees species that did not reach light saturation below 2,000 µmol m−2 s−1. A light intensity of 1,000 µmol m−2 s−1 sufficed for measuring Asat of climax species at our study sites, independent of the species or the canopy height. Because of the wide light saturation ranges, results from studies measuring Asat at higher PPFD levels (for upper canopy leaves up to 1,600 µmol m−2 s−1) are comparable with studies measuring at 1,000 µmol m−2 s−1. © 2020 The Association for Tropical Biology and Conservation |
| Address |
UMR 5174, Laboratoire Evolution et Diversité Biologique, CNRS, Université Paul Sabatier, Toulouse, 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 |
00063606 (Issn) |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
|
Approved |
no |
| Call Number |
EcoFoG @ webmaster @ |
Serial |
948 |
| Permanent link to this record |
| |
|
| |
| Author |
Veron, V.; Caron, H.; Degen, B. |
| Title |
Gene flow and mating system of the tropical tree Sextonia rubra |
Type |
Journal Article |
| Year |
2005 |
Publication |
Silvae Genetica |
Abbreviated Journal |
Silvae Genet. |
| Volume |
54 |
Issue |
6 |
Pages |
275-280 |
| Keywords |
genetic diversity; gene flow; heterozygosity; microsatellites; mixed mating; tropical tree; twogener |
| Abstract |
In this paper we report a study of the mating system and gene flow of Sextonia rubra, a hermaphroditic, insect pollinated tropical tree species with a geographic distribution in the Guyana Plateau and the Amazon. Using five microsatellites we analysed 428 seeds of 27 open pollinated families at the experimental site “Paracou” in French Guiana. We observed, compared to other tropical tree species, a high level of genetic diversity. We estimated parameters of the mating system and gene flow by using the mixed mating model and the TwoGener approach. The estimated multilocus outcrossing rate, t(m), was 0.992 indicating nearly complete outcrossing. A significant level of biparental inbreeding and a:small proportion. of full-sibs were estimated for the 27 seed arrays. The differentiation of allelic frequencies among the pollen pools was (Phi(FT) = 0.061. We estimated mean pollen dispersal distances between 65 m and 89 m according to the dispersal models used. The joint estimation of pollen dispersal and density of reproductive trees gave an effective density estimate of 2.1-2.2 trees/ha. |
| Address |
INRA, UMR, ECOFOG, Kourou 9738, French Guiana, Email: b.degen@holz.uni-hamburg.de |
| Corporate Author |
|
Thesis |
|
| Publisher |
J D SAUERLANDERS VERLAG |
Place of Publication |
|
Editor |
|
| Language |
|
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0037-5349 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
ISI:000235239400005 |
Approved |
no |
| Call Number |
EcoFoG @ eric.marcon @ |
Serial |
182 |
| Permanent link to this record |
| |
|
| |
| Author |
Verheyen, K.; Vanhellemont, M.; Auge, H.; Baeten, L.; Baraloto, C.; Barsoum, N.; Bilodeau-Gauthier, S.; Bruelheide, H.; Castagneyrol, B.; Godbold, D.; Haase, J.; Hector, A.; Jactel, H.; Koricheva, J.; Loreau, M.; Mereu, S.; Messier, C.; Muys, B.; Nolet, P.; Paquette, A.; Parker, J.; Perring, M.; Ponette, Q.; Potvin, C.; Reich, P.; Smith, A.; Weih, M.; Scherer-Lorenzen, M. |
| Title |
Contributions of a global network of tree diversity experiments to sustainable forest plantations |
Type |
Journal Article |
| Year |
2016 |
Publication |
Ambio |
Abbreviated Journal |
Ambio |
| Volume |
45 |
Issue |
1 |
Pages |
29-41 |
| Keywords |
Biodiversity experiments; Ecological restoration; Functional biodiversity research; Plantation forest; Sustainable forest management |
| Abstract |
The area of forest plantations is increasing worldwide helping to meet timber demand and protect natural forests. However, with global change, monospecific plantations are increasingly vulnerable to abiotic and biotic disturbances. As an adaption measure we need to move to plantations that are more diverse in genotypes, species, and structure, with a design underpinned by science. TreeDivNet, a global network of tree diversity experiments, responds to this need by assessing the advantages and disadvantages of mixed species plantations. The network currently consists of 18 experiments, distributed over 36 sites and five ecoregions. With plantations 1–15 years old, TreeDivNet can already provide relevant data for forest policy and management. In this paper, we highlight some early results on the carbon sequestration and pest resistance potential of more diverse plantations. Finally, suggestions are made for new, innovative experiments in understudied regions to complement the existing network. © 2015, Royal Swedish Academy of Sciences. |
| Address |
Department of Crop Production Ecology, Swedish University of Agricultural Sciences, PO Box 7043, Uppsala, Sweden |
| 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 2016 |
Approved |
no |
| Call Number |
EcoFoG @ webmaster @ |
Serial |
652 |
| Permanent link to this record |
| |
|
| |
| Author |
Vergne, Antoine ; Darbot, Vincent ; Bardot, Corinne ; Enault, François ; Le Jeune, Anne-Hélène ; Carrias, Jean-François ; Corbara, Bruno ; Céréghino, Régis ; Leroy, Celine ; Jeanthon, Christian ; Giraud, Eric ; Mary, Isabelle ; Lehours, Anne-Catherine |
| Title |
Assemblages of anoxygenic phototrophic bacteria in tank bromeliads exhibit a host-specific signatureit |
Type |
Journal Article |
| Year |
2021 |
Publication |
Journal of Ecology |
Abbreviated Journal |
|
| Volume |
109 |
Issue |
7 |
Pages |
2550-2565 |
| Keywords |
|
| Abstract |
Anoxygenic phototrophic bacteria (APB) are a very significant metabolic functional group in the phytotelmata of tank-forming Bromeliaceae plants. Considering the close relationships existing between the bromeliad and its tank microbiota, the dominance of APB raises the question of their role in the ecology and evolution of these plants. Here, using pufM gene sequencing for taxonomic profiling, we investigated the structure of APB communities in the tanks of five bromeliad species exhibiting different habitat characteristics (i.e. physicochemical factors associated with the host), and occurring in different localities of French Guiana.
We found that APB assemblages were specific to plant species and were less dependent on location or on bromeliad habitat characteristics. This convergence suggests that the identity of the bromeliad species per se is more important than habitat filtering or dispersal to control specific assembly rules for APB. The pufM OTUs were affiliated with five orders of Alpha- and Beta-proteobacteria (Rhodobacterales, Sphingomonadales, Rhizobiales, Burkholderiales and Rhodospirillales), and we assume that they may be major components of the core microbiota of plant-held waters. Our findings also revealed that up to 79% of the sequences were affiliated with APB clades possessing nitrogen-fixing genes suggesting that this metabolic capability is widespread within the APB community inhabiting tank bromeliads. We hypothesized that bromeliads may benefit nutritionally from associations with free-living APB capable to fix atmospheric nitrogen. Synthesis. Understanding the dominance of APB in tank bromeliads and determining whether a potential interplay exists between these partners is an intriguing aspect of possible mutualistic and coevolving interactions between the two existing forms of chlorophototrophy (i.e. bacteriochlorophyll-based anoxygenic and chlorophyll-based oxygenic phototrophy). In the present study, we found that bromeliad species was the main factor that explained variance in APB community composition. These findings suggest that APB and tank bromeliads may have a close, mutualistic relationship and we hypothesize according to our genomic analyses that APB may promote the bromeliad growth by provisioning essential nutrients like nitrogen. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
British Ecological Society |
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 |
|
Approved |
no |
| Call Number |
EcoFoG @ webmaster @ |
Serial |
1023 |
| Permanent link to this record |
| |
|
| |
| Author |
Verbeeck, H.; Peylin, P.; Bacour, C.; Bonal, D.; Steppe, K.; Ciais, P. |
| Title |
Seasonal patterns of CO2 fluxes in Amazon forests: Fusion of eddy covariance data and the ORCHIDEE model |
Type |
Journal Article |
| Year |
2011 |
Publication |
Journal Of Geophysical Research-Biogeosciences |
Abbreviated Journal |
J. Geophys. Res.-Biogeosci. |
| Volume |
116 |
Issue |
2 |
Pages |
G02018 |
| Keywords |
|
| Abstract |
[1] In some regions of the Amazon, global biogeophysical models have difficulties in reproducing measured seasonal patterns of net ecosystem exchange (NEE) of carbon dioxide. The global process-based biosphere model Organizing Carbon and Hydrology in Dynamic Ecosystems (ORCHIDEE) used in this study showed that a standard model parameterization produces seasonal NEE patterns that are opposite in phase to the eddy flux data of the tropical evergreen forest at the Tapajos km 67 site (Brazil), like many other global models. However, we optimized several key parameters of ORCHIDEE using eddy covariance data of the Tapajos km 67 site in order to identify the driving factors of the seasonal variations in CO2 flux in this tropical forest ecosystem. The validity of the retrieved parameter values was evaluated for two other flux tower sites in the Amazon. The different tested optimization scenarios showed that only a few parameters substantially improve the fit to NEE and latent heat data. Our results confirm that these forests have the ability to maintain high transpiration and photosynthesis during the dry season in association with a large soil depth (D-soil = 10 m) and a rooting system density that decreases almost linearly with depth (H-root = 0.1). Previous analyses of seasonal variations in eddy covariance fluxes indicated that higher GPP levels were reached in the dry season compared to the wet season. Our optimization analysis suggests that this pattern could be caused by a leaf flush at the start of the dry season increasing the photosynthetic capacity of the canopy. Nevertheless, the current model structure is not yet able to simulate such a leaf flush, and we therefore suggest improving the ORCHIDEE model by including a specific phenology module that is driven by light availability for the tropical evergreen plant functional types. In addition, our results highlight both the potential and the limitations of flux data to improve global terrestrial models. Several parameters were not identifiable, and the risk of overfitting of the model was illustrated. Nevertheless, we conclude that these models can be improved substantially by assimilating site level flux data over the tropics. |
| Address |
[Verbeeck, Hans; Steppe, Kathy] Univ Ghent, Plant Ecol Lab, Dept Appl Ecol & Environm Biol, Fac Biosci Engn, B-9000 Ghent, Belgium, Email: hans.verbeeck@ugent.be |
| Corporate Author |
|
Thesis |
|
| Publisher |
Amer Geophysical Union |
Place of Publication |
|
Editor |
|
| Language |
|
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0148-0227 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
ISI:000290933500002 |
Approved |
no |
| Call Number |
EcoFoG @ webmaster @ |
Serial |
321 |
| Permanent link to this record |
