Original Article

Low functional but large soil-related variations in growth trajectories characterize the widespread Neotropical tree Cecropia obtusa Trécul (Urticaceae)Comment by Seb L.: François Munoz:I would suggest changing the title to better underline the take-home message. For instance, "Growth trajectories better reflect the influence of soil variation than functional traits in a widespread neotropical tree"Comment by Seb L.: We keep it. Thanks!

Growth trajectories better reflect the influence of soil variation than functional traits in a widespread pioneer Neotropical tree

Running title: Soil-related phenotypic variability for a widespread tree species

Sébastien Levionnois1*, Niklas Tysklind2, Eric Nicolini3, Bruno Ferry4, Valérie Troispoux2, Gilles Le Moguedec5, Hélène Morel6, Clément Stahl2, Sabrina Coste7, Henri Caron2, 8, Patrick Heuret2, 5*

1. CNRS, UMR EcoFoG, AgroParisTech, CIRAD, CNRS, INRA, Université des Antilles, Université de Guyane, 97310 Kourou, France.

2. INRA, UMR EcoFoG, AgroParisTech, CIRAD, CNRS, INRA, Université des Antilles, Université de Guyane, 97310 Kourou, France.

3. CIRAD, UMR AMAP, CIRAD, CNRS, INRA, IRD, Université de Montpellier, 34398 Montpellier, France.

4. AgroParisTech, UMR LERFoBSILVA, AgroParisTech, INRA, 54280 Champenoux, France.Comment by Seb L.: Georges Kunstler:“UMR LerFoB” change to “UMR Silva”, no?Comment by Seb L.: Yes, the correction has been added. The writing of our manuscript started before this change.

5. INRA, UMR AMAP, CIRAD, CNRS, INRA, IRD, Université de Montpellier, 34398 Montpellier, France.

6. CIRAD, UMR EcoFoG, AgroParisTech, CIRAD, CNRS, INRA, Université des Antilles, Université de Guyane, 97310 Kourou, France.

7. Université de Guyane, UMR EcoFoG, AgroParisTech, CIRAD, CNRS, INRA, Université des Antilles, Université de Guyane, 97310 Kourou, France.

8. INRA, UMR BIOGECO, INRA, Université de Bordeaux, Cestas, France

*Authors for correspondence:

Sébastien Levionnois, PhD student

Postal adress: UMR EcoFog, Campus Agronomique, Avenue de France

BP709 – 97387 Kourou Cedex

French Guiana

Tel: +33 760 26 73 83

Email: sebastien_levionnois@live.fr

Patrick Heuret, PhD

Postal adress: UMR AMAP, TA- A-51/PS2 Boulevard de la Lironde

34398 Montpellier Cedex 5 (France)

French Guiana

Tel: +33 467 61 55 14

Email: patrick.heuret@inra.fr

Author contributions

PH designed and led the project. PH, SL, EN, VT, HM, NT, CS, SC, BF and HC .measured tree architecture and functional traits. BF and VT described soils characteristics. SL, PH and GL performed data analysis. SL wrote the manuscript with contributions from PH and NT. All authors contributed critically to the drafts and gave final approval for publication.Comment by Seb L.: Georges Kunstler:delete the pointComment by Seb L.: Done

ABSTRACT

1. Trait-environment relationships have been described at the community level across tree species. However, whether interspecific trait-environment relationships are maintained at the intraspecific level is yet unknown.

1. Environment-driven interspecific functional variability has been convincingly described across Amazon lowland tree species. However, functional variability has rarely been addressed at the intraspecific level, especially through one key environmental driver such as soil composition. In this study, we assess whether patterns of soil-dependent interspecific variability are retained at the intraspecific level.

2. We examined phenotypic variability for 16 functional leaf (dimensions, nutrient, chlorophyll) and wood traits (density) across two soil types, Ferralitic Soil (FS) vs. White Sands (WS), and on two sites for 70 adult trees of Cecropia obtusa Trécul (Urticaceae) in French Guiana. Cecropia is a widespread pioneer Neotropical genus that generally dominates forest early successional stages. To understand how soil types impact resource-use through the processes of growth and branching, we examined the architectural development with a retrospective analysis of growth trajectories.We also examined the architectural development through a temporal-scaled retrospective analysis and lifespan-level growth trajectories, in order to evaluate the role of soil phenotypic variability. Cecropia’s unique features, such as simple architecture and growth markers allowed us detailed description of temporal-scaled retrospective analysis of development.Comment by Seb L.: Georges Kunstler:delete “and on” and replace by “over”?Comment by Seb L.: Done

3. Functional trait responses to soil types were weak, as only two traits, namely petiole length and leaf area, -leaf residual water content and K content- exhibited showed significant differences between the twoacross soil types. Soil effects were stronger on growth trajectories and tree architectural development, with WS trees having the slower growth trajectories -mediated through smaller internode length-, smaller trunk heights and diameters for a given age, and less numerous branches across their lifespan.

4. The analysis of growth trajectories based on architectural analysis improved our ability to detect the effects of soil types compared to measured functional traits. Intraspecific variability is higher for growth trajectories than functional traits for C. obtusa, revealing the higher sensitivity of the architectural approach in comparison to the functional approach in the case of C. obtusa. Soil-related response of Cecropia functional traits is not homologous to the community-level environmental filtering, suggesting that the effects of the acting ecological processes are different between the two levels.

4. Soil-related functional traits did not mirror the divergence usually found at the interspecific level. By integrating a dynamic approach based on retrospective analysis of architectural development to the functional approach to understand tree ecology, here, we demonstrate how an improved understanding of environmental effects on tree phenotypic variance can be captured.

Key words: architecture, Cecropia obtusa, ferralitic/white-sand soils, functional traits, growth trajectory, intraspecific variability

INTRODUCTION

Trait-based community ecology seeks to predict the processes of assemblage and maintenance of plant communities over time and space (McGill et al. 2006). The key questions in this field are (i) the identification of ecological processes determining community composition (McGill et al. 2006; Shipley et al. 2016), and (ii) the role of intraspecific variability (ITV) in community assemblages, and to what extent ITV can be ignored by using species-level functional trait means, (Violle et al. 2012; Shipley et al. 2016). Trait-based approaches have improved our understanding of the role of ecological processes in community assemblage. Environmental filtering drives community assemblage through the interaction of individuals with the abiotic environment (Kraft et al. 2015): Physiologically challenged individuals are eliminated, so that the breadth of functional trait values is predicted to be small (i.e. functional trait under-dispersion) within local communities. Another process, niche differentiation is based on the interaction of neighbouring individuals, and incorporates the effects of both resource competition and shared predators (Uriarte et al. 2004). For species co-existence, they cannot share exactly the same niche, such that evenness of functional trait value distribution is predicted to be high, leading to functional trait over-dispersion within local communities. Both ecological processes, environmental filtering and niche differentiation, have been demonstrated for various habitats and landscapes, with environmental filtering tending to be more pervasive (Kraft et al. 2008; Swenson and Enquist 2009; Paine et al. 2011; HilleRisLambers et al. 2012).

ITV has long been ignored, or at least underestimated, in trait-based community ecology (Violle et al. 2012; Shipley et al. 2016). This has been the case for studies investigating ecological processes of community assemblages (Schamp et al. 2008; Kraft et al. 2008; Swenson and Enquist 2009); but see (Paine et al. (2011). ITV may allow a species to thrive in several communities. First, displaying a large ITV would allow a species to fit a large abiotic spectrum, since there is a higher probability that the required functional trait values compatible with the habitat fall into the possible range of functional trait values of the species. In such a case, the success of individuals in terms of environmental filtering is promoted. Second, displaying a large ITV allows different ways to avoid functional trait similarity with neighbours, and contributes to the niche differentiation among habitats. Recent efforts for incorporating ITV into trait-based community ecology have validated these hypotheses (Fridley and Grime 2010; Jung et al. 2010, 2014; Lepš et al. 2011; Kraft et al. 2014). Moreover, studies have demonstrated that incorporating ITV increases the predictive power of models for species interactions, trait-environment relationships, and ecosystem productivity (Jung et al. 2010; Paine et al. 2011).

Generalist species are particularly useful to understand the role of ITV and environmental filtering in the structuring of community composition. Generalist species are defined here as species able to thrive within a larger range of abiotic conditions than most of species, and generally regarding one kind of condition, i.e. topographic, edaphic, light... First, generalist species tend to display large ITV, and by definition they inhabit large ecological spectrums (Sides et al. 2014). Generalist species offer the opportunity to test hypotheses regarding how ecological processes act at the intraspecific level, how functional traits are mediated regarding the ecological processes, and if they do so in the same way than at the interspecific level. Second, better knowledge on how ITV of functional traits is structured should help to better decide if and how ITV must be accounted for in trait-based community ecology, especially for generalist species, which are often regionally widespread and abundant (Holt et al. 2002; Borregaard and Rahbek 2010; Boulangeat et al. 2012).

In the Amazon forest, abiotic factors such as edaphic conditions are habitat filters and strong drivers of species distribution ADDIN ZOTERO_ITEM CSL_CITATION {"citationID":"ajj3e66mrs","properties":{"formattedCitation":"(Alli\\uc0\\u233{} et al., 2015; Baraloto, Morneau, Bonal, Blanc, & Ferry, 2007; Clark, Palmer, & Clark, 1999; Guitet et al., 2016; John et al., 2007; Kanagaraj, Wiegand, Comita, & Huth, 2011; P\\uc0\\u233{}lissier, Dray, & Sabatier, 2002; Sabatier et al., 1997; Stropp, Sleen, Assun\\uc0\\u231{}\\uc0\\u227{}o, Silva, & Steege, 2011; ter Steege, Jetten, Polak, & Werger, 1993; Valencia et al., 2004)","plainCitation":"(Allié et al., 2015; Baraloto, Morneau, Bonal, Blanc, & Ferry, 2007; Clark, Palmer, & Clark, 1999; Guitet et al., 2016; John et al., 2007; Kanagaraj, Wiegand, Comita, & Huth, 2011; Pélissier, Dray, & Sabatier, 2002; Sabatier et al., 1997; Stropp, Sleen, Assunção, Silva, & Steege, 2011; ter Steege, Jetten, Polak, & Werger, 1993; Valencia et al., 2004)","noteIndex":0},"citationItems":[{"id":"fCAS7BvH/MZANwc2D","uris":["http://zotero.org/users/local/9u60twst/items/AWF2KNCQ"],"uri":["http://zotero.org/users/local/9u60twst/items/AWF2KNCQ"],"itemData":{"id":1078,"type":"article-journal","title":"Tropical rain forest types and soil factors in a watershed area in Guyana","container-title":"Journal of Vegetation Science","page":"705-716","volume":"4","issue":"5","source":"Wiley Online Library","abstract":"Abstract. An inventory was made of the vegetation and soils of a watershed area of 480 ha in the tropical rain forest of Guyana. 252 plots of 0.05 ha were sampled. In total 111 tree species > 20 cm were recorded. A TWINSPAN analysis resulted in seven groupings. Correspondence Analysis revealed that the major environmental differentiation underlying the floristic variation is according to soil type. Finally, five main forest communities were described. Most sites in the watershed area are characterized by the dominance of one or a few species. Species distribution patterns are strongly determined by soil type and drainage class.","DOI":"10.2307/3236137","ISSN":"1654-1103","language":"en","author":[{"family":"Steege","given":"Hans","non-dropping-particle":"ter"},{"family":"Jetten","given":"Victor G."},{"family":"Polak","given":"A. Marcel"},{"family":"Werger","given":"Marinus J. A."}],"issued":{"date-parts":[["1993",10,1]]}}},{"id":"fCAS7BvH/3dWgyefj","uris":["http://zotero.org/users/local/9u60twst/items/3NDUDEIV"],"uri":["http://zotero.org/users/local/9u60twst/items/3NDUDEIV"],"itemData":{"id":807,"type":"article-journal","title":"The influence of soil cover organization on the floristic and structural heterogeneity of a Guianan rain forest","container-title":"Plant Ecology","page":"81-108","volume":"131","issue":"1","source":"link.springer.com","abstract":"The impact of soil cover organization on the forest community has been studied in a 19-ha tract at Piste de St Elie station in French Guiana. 195 species each represented by at least 10 individuals we","DOI":"10.1023/A:1009775025850","ISSN":"1385-0237, 1573-5052","journalAbbreviation":"Plant Ecology","language":"en","author":[{"family":"Sabatier","given":"Daniel"},{"family":"Grimaldi","given":"Michel"},{"family":"Prévost","given":"Marie-Françoise"},{"family":"Guillaume","given":"Julie"},{"family":"Godron","given":"Michel"},{"family":"Dosso","given":"Mireille"},{"family":"Curmi","given":"Pierre"}],"issued":{"date-parts":[["1997",7,1]]}}},{"id":"fCAS7BvH/Kk0eevfl","uris":["http://zotero.org/users/local/9u60twst/items/78KUNJX6"],"uri":["http://zotero.org/users/local/9u60twst/items/78KUNJX6"],"itemData":{"id":1080,"type":"article-journal","title":"Edaphic Factors and the Landscape-Scale Distributions of Tropical Rain Forest Trees","container-title":"Ecology","page":"2662-2675","volume":"80","issue":"8","source":"Wiley Online Library","abstract":"Tropical rain forests have the highest tree diversity on earth. Nonrandom spatial distributions of these species in relation to edaphic factors could be one mechanism responsible for maintaining this diversity. We examined the prevalence of nonrandom distributions of trees and palms in relation to soil type and topographic position (“edaphic biases”) over a mesoscale (573 ha) old-growth tropical rain forest (TRF) landscape at the La Selva Biological Station, Costa Rica. All trees and palms ≥10 cm diameter were measured and identified in 1170 circular 0.01-ha plots centered on an existing 50 × 100 m grid. Topographic position was classified for each plot, and slope and aspect were measured. Soil type data were taken from a previous study (Clark et al. 1998). A total of 5127 trees and palms were identified in 267 species. Detrended Correspondence Analysis and Canonical Correspondence Analysis showed that highly significant edaphic gradients were present, with swamp or highly fertile soils separated from the less fertile, well-drained upland soils. Species composition remained significantly related to topographic position when soil type was controlled for. The main floristic gradients were still significant when flooded sites were excluded from the analyses. Randomization tests on a weighted preference index were used to examine the relations of individual species to soil types and, within the dominant soil type, to topographic position. Of the 132 species with N ≥ 5 individuals, 33 showed significant associations with soil type. Within the dominant soil type, 13 of 110 analyzable species were nonrandomly associated with one or more topographic positions. For a variety of reasons, including issues relating to sample size and adequate edaphic characterization of landscapes, we suggest that the ∼30% of species shown to be edaphically biased in this study is an underestimate of the true degree of edaphically related distributional biases. To evaluate this hypothesis will require mesoscale vegetation sampling combined with quantitative soil analyses at the same scale in a range of tropical rain forests. If edaphic distributional biases are shown to be common, this suggests that edaphically linked processes leading to differential recruitment are similarly common.","DOI":"10.1890/0012-9658(1999)080[2662:EFATLS]2.0.CO;2","ISSN":"1939-9170","language":"en","author":[{"family":"Clark","given":"David B."},{"family":"Palmer","given":"Michael W."},{"family":"Clark","given":"Deborah A."}],"issued":{"date-parts":[["1999",12,1]]}}},{"id":"fCAS7BvH/cz3CPtBx","uris":["http://zotero.org/users/local/9u60twst/items/Q68CN6T9"],"uri":["http://zotero.org/users/local/9u60twst/items/Q68CN6T9"],"itemData":{"id":113,"type":"article-journal","title":"Within-Plot Relationships between Tree Species Occurrences and Hydrological Soil Constraints: An Example in French Guiana Investigated through Canonical Correlation Analysis","container-title":"Plant Ecology","page":"143-156","volume":"162","issue":"2","source":"JSTOR","abstract":"Spatial relationships between tree species and hydrological soil constraints are analysed within a 10-ha rainforest plot at Piste de St Elie in French Guiana. We used canonical correlation analysis to cross directly the occurrence-by-species table of 4 992 individuals (d.b.h. ≥ 10 cm) belonging to 120 species with qualitative soil variables and quantitative spatial data. Firstly, the list of species occurrences was confronted to nine soil descriptors characterising a weathering sequence from the initial well-drained ferralitic cover to transformed hydromorphic soil conditions. This analysis revealed that, apart from some specialised species restricted to the swamps that experience prolonged water saturation, the most abundant species can be ordered along two intermingled gradients of tolerance limiting their niche amplitude: a main gradient of tolerance to prolonged water saturation that appears down slope during the weathering sequence; a second gradient of less importance, displaying the species intolerant of prolonged water saturation according to their tolerance to temporary confinement of the uphill transformed soil systems due to the late appearance of a perched water-table. The results support the hypothesis that at Piste de St Elie, the constraining soil conditions imposed by surface water saturation are more important determinants for tree zonation of many tree species than water shortage. Secondly, the list of species occurrences was confronted to a spatial data table built from a trend surface regression of the tree coordinates. This analysis indicated that soil drainage is the main structuring factor of the local multispecies spatial pattern. After partialling out the soil effect, the multispecies pattern revealed a broader scale of heterogeneity that we supposed to be linked to endogenous factors resulting from population dynamics. Implications of the results are then discussed in the perspective of future research on tree zonation, local diversity pattern and community structuring in tropical rainforests.","ISSN":"1385-0237","shortTitle":"Within-Plot Relationships between Tree Species Occurrences and Hydrological Soil Constraints","journalAbbreviation":"Plant Ecology","author":[{"family":"Pélissier","given":"Raphaël"},{"family":"Dray","given":"Stéphane"},{"family":"Sabatier","given":"Daniel"}],"issued":{"date-parts":[["2002"]]}}},{"id":"fCAS7BvH/YUD2DwfQ","uris":["http://zotero.org/users/local/9u60twst/items/ER7FPQHW"],"uri":["http://zotero.org/users/local/9u60twst/items/ER7FPQHW"],"itemData":{"id":1082,"type":"article-journal","title":"Tree species distributions and local habitat variation in the Amazon: large forest plot in eastern Ecuador","container-title":"Journal of Ecology","page":"214-229","volume":"92","issue":"2","source":"Wiley Online Library","abstract":"1 We mapped and identified all trees ≥ 10 mm in diameter in 25 ha of lowland wet forest in Amazonian Ecuador, and found 1104 morphospecies among 152 353 individuals. The largest number of species was mid-sized canopy trees with maximum height 10–20 m and understorey treelets with maximum height of 5–10 m. 2 Several species of understorey treelets in the genera Matisia and Rinorea dominated the forest numerically, while important canopy species were Iriartea deltoidea and Eschweilera coriacea. 3 We examined how species partition local topographic variation into niches, and how much this partitioning contributes to forest diversity. Evidence in favour of topographic niche-partitioning was found: similarity in species composition between ridge and valley quadrats was lower than similarity between two valley (or two ridge) quadrats, and 25% of the species had large abundance differences between valley and ridge-top. On the other hand, 25% of the species were generalists, with similar abundance on both valley and ridges, and half the species had only moderate abundance differences between valley and ridge. 4 Topographic niche-partitioning was not finely grained. There were no more than three distinct vegetation zones: valley, mid-slope, and upper-ridge, and the latter two differed only slightly in species composition. 5 Similarity in species composition declined with distance even within a topographic habitat, to about the same degree as it declined between habitats. This suggests patchiness not related to topographic variation, and possibly due to dispersal limitation. 6 We conclude that partitioning of topographic niches does make a contribution to the α-diversity of Amazonian trees, but only a minor one. It provides no explanation for the co-occurrence of hundreds of topographic generalists, nor for the hundreds of species with similar life-form appearing on a single ridge-top.","DOI":"10.1111/j.0022-0477.2004.00876.x","ISSN":"1365-2745","shortTitle":"Tree species distributions and local habitat variation in the Amazon","language":"en","author":[{"family":"Valencia","given":"Renato"},{"family":"Foster","given":"Robin B."},{"family":"Villa","given":"Gorky"},{"family":"Condit","given":"Richard"},{"family":"Svenning","given":"Jens-Christian"},{"family":"Hernández","given":"Consuelo"},{"family":"Romoleroux","given":"Katya"},{"family":"Losos","given":"Elizabeth"},{"family":"Magård","given":"Else"},{"family":"Balslev","given":"Henrik"}],"issued":{"date-parts":[["2004",4,1]]}}},{"id":"fCAS7BvH/mZi1L7H3","uris":["http://zotero.org/users/local/9u60twst/items/HQ5QCRY4"],"uri":["http://zotero.org/users/local/9u60twst/items/HQ5QCRY4"],"itemData":{"id":1083,"type":"article-journal","title":"Soil nutrients influence spatial distributions of tropical tree species","container-title":"Proceedings of the National Academy of Sciences","page":"864-869","volume":"104","issue":"3","source":"www.pnas.org","abstract":"The importance of niche vs. neutral assembly mechanisms in structuring tropical tree communities remains an important unsettled question in community ecology [Bell G (2005) Ecology 86:1757–1770]. There is ample evidence that species distributions are determined by soils and habitat factors at landscape (<104 km2) and regional scales. At local scales (<1 km2), however, habitat factors and species distributions show comparable spatial aggregation, making it difficult to disentangle the importance of niche and dispersal processes. In this article, we test soil resource-based niche assembly at a local scale, using species and soil nutrient distributions obtained at high spatial resolution in three diverse neotropical forest plots in Colombia (La Planada), Ecuador (Yasuni), and Panama (Barro Colorado Island). Using spatial distribution maps of >0.5 million individual trees of 1,400 species and 10 essential plant nutrients, we used Monte Carlo simulations of species distributions to test plant–soil associations against null expectations based on dispersal assembly. We found that the spatial distributions of 36–51% of tree species at these sites show strong associations to soil nutrient distributions. Neutral dispersal assembly cannot account for these plant–soil associations or the observed niche breadths of these species. These results indicate that belowground resource availability plays an important role in the assembly of tropical tree communities at local scales and provide the basis for future investigations on the mechanisms of resource competition among tropical tree species.","DOI":"10.1073/pnas.0604666104","ISSN":"0027-8424, 1091-6490","note":"PMID: 17215353","journalAbbreviation":"PNAS","language":"en","author":[{"family":"John","given":"Robert"},{"family":"Dalling","given":"James W."},{"family":"Harms","given":"Kyle E."},{"family":"Yavitt","given":"Joseph B."},{"family":"Stallard","given":"Robert F."},{"family":"Mirabello","given":"Matthew"},{"family":"Hubbell","given":"Stephen P."},{"family":"Valencia","given":"Renato"},{"family":"Navarrete","given":"Hugo"},{"family":"Vallejo","given":"Martha"},{"family":"Foster","given":"Robin B."}],"issued":{"date-parts":[["2007",1,16]]}}},{"id":"fCAS7BvH/ypt4aNEY","uris":["http://zotero.org/users/local/9u60twst/items/C6S7RMAE"],"uri":["http://zotero.org/users/local/9u60twst/items/C6S7RMAE"],"itemData":{"id":879,"type":"article-journal","title":"Seasonal water stress tolerance and habitat associations within four neotropical tree genera","container-title":"Ecology","page":"478-489","volume":"88","issue":"2","source":"onlinelibrary.wiley.com","abstract":"We investigated the relationship between habitat association and physiological performance in four congeneric species pairs exhibiting contrasting distributions between seasonally flooded and terra firme...","DOI":"10.1890/0012-9658(2007)88[478:SWSTAH]2.0.CO;2","ISSN":"1939-9170","language":"en","author":[{"family":"Baraloto","given":"Christopher"},{"family":"Morneau","given":"François"},{"family":"Bonal","given":"Damien"},{"family":"Blanc","given":"Lilian"},{"family":"Ferry","given":"Bruno"}],"issued":{"date-parts":[["2007",2,1]]}}},{"id":"fCAS7BvH/EwaGZnxd","uris":["http://zotero.org/users/local/9u60twst/items/PW86RQW8"],"uri":["http://zotero.org/users/local/9u60twst/items/PW86RQW8"],"itemData":{"id":1087,"type":"article-journal","title":"Tree communities of white-sand and terra-firme forests of the upper Rio Negro","container-title":"Acta Amazonica","page":"521-544","volume":"41","issue":"4","source":"SciELO","DOI":"10.1590/S0044-59672011000400010","ISSN":"0044-5967","author":[{"family":"Stropp","given":"Juliana"},{"family":"Sleen","given":"Peter Van","dropping-particle":"der"},{"family":"Assunção","given":"Paulo Apóstolo"},{"family":"Silva","given":"Adeilson Lopes","dropping-particle":"da"},{"family":"Steege","given":"Hans Ter"}],"issued":{"date-parts":[["2011"]]}}},{"id":"fCAS7BvH/z42tj0GF","uris":["http://zotero.org/users/local/9u60twst/items/9Y7KBUUY"],"uri":["http://zotero.org/users/local/9u60twst/items/9Y7KBUUY"],"itemData":{"id":1085,"type":"article-journal","title":"Tropical tree species assemblages in topographical habitats change in time and with life stage","container-title":"Journal of Ecology","page":"1441-1452","volume":"99","issue":"6","source":"Wiley Online Library","abstract":"1. Recent studies have documented shifts in habitat associations of single tropical tree species from one life stage to the next. However, the community-level consequences of such shifts have not been investigated, and it is not clear whether they would amplify, neutralize or completely alter habitat structuring during the transitions to the adult community. 2. We compared habitat-driven species assemblages at three life stages (i.e. recruitment, juvenile and reproductive stages) and six censuses for tree and shrub species in a fully censused 50-ha plot of Panamanian lowland forest. Habitat types were determined using multivariate regression trees that group areas with similar species composition (i.e. species assemblages) according to their topographical characteristics. 3. Three topographical variables (a topographical wetness index, slope and elevation) were major determinants of species assemblages. When analysing individuals of all life stages together, we found a distinct and temporally consistent structuring of the plot into four dominant habitat types (low and high plateaus, slope and swamp) which was consistent with previous classifications. Basically, the same habitat structuring emerged for the juvenile communities of individual censuses. However, recruits showed a weak and temporally inconsistent habitat structuring. 4. A notable homogenization in species assemblages occurred during the transition from juvenile to reproductive, through both a reduction in the number of species assemblages (in 3 censuses, one large reproductive assemblage covered 93% of the plot, and in others, an additional slope habitat emerged) and a reduction in the classification error. Overall, habitat structuring became noisier and weaker over the 25 years of the study. 5.Synthesis. Our results suggest that mortality processes during the transition from recruits to juveniles must enhance the signal of habitat structuring. However, during the transition to the reproductive stage, species may have lost the advantage of being in the habitat with which they had become associated, or the quality of habitat changed during their life span because of larger climatic changes. The homogeneous assemblages of the reproductive stage could be interpreted as support for neutral theories, but further research is required to unravel the mechanisms behind these intriguing observations.","DOI":"10.1111/j.1365-2745.2011.01878.x","ISSN":"1365-2745","language":"en","author":[{"family":"Kanagaraj","given":"Rajapandian"},{"family":"Wiegand","given":"Thorsten"},{"family":"Comita","given":"Liza S."},{"family":"Huth","given":"Andreas"}],"issued":{"date-parts":[["2011",11,1]]}}},{"id":"fCAS7BvH/k4bf7z7I","uris":["http://zotero.org/users/local/9u60twst/items/UBBR8XQF"],"uri":["http://zotero.org/users/local/9u60twst/items/UBBR8XQF"],"itemData":{"id":419,"type":"article-journal","title":"Pervasive Local-Scale Tree-Soil Habitat Association in a Tropical Forest Community","container-title":"PLOS ONE","page":"e0141488","volume":"10","issue":"11","source":"journals.plos.org","abstract":"We examined tree-soil habitat associations in lowland forest communities at Paracou, French Guiana. We analyzed a large dataset assembling six permanent plots totaling 37.5 ha, in which extensive LIDAR-derived topographical data and soil chemical and physical data have been integrated with precise botanical determinations. Map of relative elevation from the nearest stream summarized both soil fertility and hydromorphic characteristics, with seasonally inundated bottomlands having higher soil phosphate content and base saturation, and plateaus having higher soil carbon, nitrogen and aluminum contents. We employed a statistical test of correlations between tree species density and environmental maps, by generating Monte Carlo simulations of random raster images that preserve autocorrelation of the original maps. Nearly three fourths of the 94 taxa with at least one stem per ha showed a significant correlation between tree density and relative elevation, revealing contrasted species-habitat associations in term of abundance, with seasonally inundated bottomlands (24.5% of species) and well-drained plateaus (48.9% of species). We also observed species preferences for environments with or without steep slopes (13.8% and 10.6%, respectively). We observed that closely-related species were frequently associated with different soil habitats in this region (70% of the 14 genera with congeneric species that have a significant association test) suggesting species-habitat associations have arisen multiple times in this tree community. We also tested if species with similar habitat preferences shared functional strategies. We found that seasonally inundated forest specialists tended to have smaller stature (maximum diameter) than species found on plateaus. Our results underline the importance of tree-soil habitat associations in structuring diverse communities at fine spatial scales and suggest that additional studies are needed to disentangle community assembly mechanisms related to dispersal limitation, biotic interactions and environmental filtering from species-habitat associations. Moreover, they provide a framework to generalize across tropical forest sites.","DOI":"10.1371/journal.pone.0141488","ISSN":"1932-6203","journalAbbreviation":"PLOS ONE","author":[{"family":"Allié","given":"Elodie"},{"family":"Pélissier","given":"Raphaël"},{"family":"Engel","given":"Julien"},{"family":"Petronelli","given":"Pascal"},{"family":"Freycon","given":"Vincent"},{"family":"Deblauwe","given":"Vincent"},{"family":"Soucémarianadin","given":"Laure"},{"family":"Weigel","given":"Jean"},{"family":"Baraloto","given":"Christopher"}],"issued":{"date-parts":[["2015",11,4]]}}},{"id":"fCAS7BvH/Yj6U25EW","uris":["http://zotero.org/users/local/9u60twst/items/YMEK5JPM"],"uri":["http://zotero.org/users/local/9u60twst/items/YMEK5JPM"],"itemData":{"id":1095,"type":"article-journal","title":"Geomorphic control of rain-forest floristic composition in French Guiana: more than a soil filtering effect?","container-title":"Journal of Tropical Ecology","page":"22-40","volume":"32","issue":"1","source":"Cambridge Core","abstract":"Abstract:The influence of geomorphological features on rain-forest diversity has been reported in different Amazonian regions. Soil filtering is often assumed to underlie the observed geomorphic control on the floristic composition but other hypotheses related to biogeography or long-term forest dynamics are also possible. We tested relationships between geomorphology, soil properties and forest composition in French Guiana rain forest using a recent geomorphological map and a large dataset comprising 3132 0.2-ha plots and 421 soil cores. Soil properties were characterized by laboratory analyses and by field descriptions indicating drainage capacity and classification according to the World Reference Base (WRB). The influence of soils and geomorphology on beta-diversity was tested using variance partitioning and ANOVA-like tests. Our results confirm the hypothesis of a strong relationship between geomorphological landscapes and soil properties. Soil filtering significantly influenced the abundance of more than 40 species or groups of species. However geomorphic control of forest composition involves much more than the effects of the soil, which only explain a minor part of the broad-scale patterns of forest diversity related to geomorphological landscapes. These results reinforce the alternative hypotheses linking geomorphological landscapes to long-term forest change under the control of historical processes that shaped forest diversity.","DOI":"10.1017/S0266467415000620","ISSN":"0266-4674, 1469-7831","shortTitle":"Geomorphic control of rain-forest floristic composition in French Guiana","language":"en","author":[{"family":"Guitet","given":"Stéphane"},{"family":"Freycon","given":"Vincent"},{"family":"Brunaux","given":"Olivier"},{"family":"Pélissier","given":"Raphaël"},{"family":"Sabatier","given":"Daniel"},{"family":"Couteron","given":"Pierre"}],"issued":{"date-parts":[["2016",1]]}}}],"schema":"https://github.com/citation-style-language/schema/raw/master/csl-citation.json"} (Allié et al., 2015; Baraloto, Morneau, Bonal, Blanc, & Ferry, 2007; Clark, Palmer, & Clark, 1999; Guitet et al., 2016; John et al., 2007; Kanagaraj, Wiegand, Comita, & Huth, 2011; Pélissier, Dray, & Sabatier, 2002; Sabatier et al., 1997; Stropp, Sleen, Assunção, Silva, & Steege, 2011; ter Steege, Jetten, Polak, & Werger, 1993; Valencia et al., 2004). Two contrasts are generally studied as edaphic factors. First, bottomland (or valley) versus hilltop (or plateau) microhabitats is the most used contrast to study species and functional turnover. Such environmental heterogeneity is mainly driven by water availability, as it is explained by topography and soil structure ADDIN ZOTERO_ITEM CSL_CITATION {"citationID":"a1j62kv3i5","properties":{"formattedCitation":"(Alli\\uc0\\u233{} et al., 2015; Sabatier et al., 1997)","plainCitation":"(Allié et al., 2015; Sabatier et al., 1997)","noteIndex":0},"citationItems":[{"id":"fCAS7BvH/3dWgyefj","uris":["http://zotero.org/users/local/9u60twst/items/3NDUDEIV"],"uri":["http://zotero.org/users/local/9u60twst/items/3NDUDEIV"],"itemData":{"id":807,"type":"article-journal","title":"The influence of soil cover organization on the floristic and structural heterogeneity of a Guianan rain forest","container-title":"Plant Ecology","page":"81-108","volume":"131","issue":"1","source":"link.springer.com","abstract":"The impact of soil cover organization on the forest community has been studied in a 19-ha tract at Piste de St Elie station in French Guiana. 195 species each represented by at least 10 individuals we","DOI":"10.1023/A:1009775025850","ISSN":"1385-0237, 1573-5052","journalAbbreviation":"Plant Ecology","language":"en","author":[{"family":"Sabatier","given":"Daniel"},{"family":"Grimaldi","given":"Michel"},{"family":"Prévost","given":"Marie-Françoise"},{"family":"Guillaume","given":"Julie"},{"family":"Godron","given":"Michel"},{"family":"Dosso","given":"Mireille"},{"family":"Curmi","given":"Pierre"}],"issued":{"date-parts":[["1997",7,1]]}}},{"id":"fCAS7BvH/k4bf7z7I","uris":["http://zotero.org/users/local/9u60twst/items/UBBR8XQF"],"uri":["http://zotero.org/users/local/9u60twst/items/UBBR8XQF"],"itemData":{"id":419,"type":"article-journal","title":"Pervasive Local-Scale Tree-Soil Habitat Association in a Tropical Forest Community","container-title":"PLOS ONE","page":"e0141488","volume":"10","issue":"11","source":"journals.plos.org","abstract":"We examined tree-soil habitat associations in lowland forest communities at Paracou, French Guiana. We analyzed a large dataset assembling six permanent plots totaling 37.5 ha, in which extensive LIDAR-derived topographical data and soil chemical and physical data have been integrated with precise botanical determinations. Map of relative elevation from the nearest stream summarized both soil fertility and hydromorphic characteristics, with seasonally inundated bottomlands having higher soil phosphate content and base saturation, and plateaus having higher soil carbon, nitrogen and aluminum contents. We employed a statistical test of correlations between tree species density and environmental maps, by generating Monte Carlo simulations of random raster images that preserve autocorrelation of the original maps. Nearly three fourths of the 94 taxa with at least one stem per ha showed a significant correlation between tree density and relative elevation, revealing contrasted species-habitat associations in term of abundance, with seasonally inundated bottomlands (24.5% of species) and well-drained plateaus (48.9% of species). We also observed species preferences for environments with or without steep slopes (13.8% and 10.6%, respectively). We observed that closely-related species were frequently associated with different soil habitats in this region (70% of the 14 genera with congeneric species that have a significant association test) suggesting species-habitat associations have arisen multiple times in this tree community. We also tested if species with similar habitat preferences shared functional strategies. We found that seasonally inundated forest specialists tended to have smaller stature (maximum diameter) than species found on plateaus. Our results underline the importance of tree-soil habitat associations in structuring diverse communities at fine spatial scales and suggest that additional studies are needed to disentangle community assembly mechanisms related to dispersal limitation, biotic interactions and environmental filtering from species-habitat associations. Moreover, they provide a framework to generalize across tropical forest sites.","DOI":"10.1371/journal.pone.0141488","ISSN":"1932-6203","journalAbbreviation":"PLOS ONE","author":[{"family":"Allié","given":"Elodie"},{"family":"Pélissier","given":"Raphaël"},{"family":"Engel","given":"Julien"},{"family":"Petronelli","given":"Pascal"},{"family":"Freycon","given":"Vincent"},{"family":"Deblauwe","given":"Vincent"},{"family":"Soucémarianadin","given":"Laure"},{"family":"Weigel","given":"Jean"},{"family":"Baraloto","given":"Christopher"}],"issued":{"date-parts":[["2015",11,4]]}}}],"schema":"https://github.com/citation-style-language/schema/raw/master/csl-citation.json"} (Allié et al., 2015; Sabatier et al., 1997). Hilltops experience higher levels of lateral and vertical water drainage due to slopes and deeper soils ADDIN ZOTERO_ITEM CSL_CITATION {"citationID":"agfguakdhb","properties":{"formattedCitation":"(Sabatier et al., 1997)","plainCitation":"(Sabatier et al., 1997)","noteIndex":0},"citationItems":[{"id":"fCAS7BvH/3dWgyefj","uris":["http://zotero.org/users/local/9u60twst/items/3NDUDEIV"],"uri":["http://zotero.org/users/local/9u60twst/items/3NDUDEIV"],"itemData":{"id":807,"type":"article-journal","title":"The influence of soil cover organization on the floristic and structural heterogeneity of a Guianan rain forest","container-title":"Plant Ecology","page":"81-108","volume":"131","issue":"1","source":"link.springer.com","abstract":"The impact of soil cover organization on the forest community has been studied in a 19-ha tract at Piste de St Elie station in French Guiana. 195 species each represented by at least 10 individuals we","DOI":"10.1023/A:1009775025850","ISSN":"1385-0237, 1573-5052","journalAbbreviation":"Plant Ecology","language":"en","author":[{"family":"Sabatier","given":"Daniel"},{"family":"Grimaldi","given":"Michel"},{"family":"Prévost","given":"Marie-Françoise"},{"family":"Guillaume","given":"Julie"},{"family":"Godron","given":"Michel"},{"family":"Dosso","given":"Mireille"},{"family":"Curmi","given":"Pierre"}],"issued":{"date-parts":[["1997",7,1]]}}}],"schema":"https://github.com/citation-style-language/schema/raw/master/csl-citation.json"} (Sabatier et al., 1997). In contrast, bottomlands receive water draining from slopes and are thus, more prone to seasonal flooding. Moreover, topographical and hydrological variations are associated with nutrient differences ADDIN ZOTERO_ITEM CSL_CITATION {"citationID":"a1fac5ji3ku","properties":{"formattedCitation":"(Alli\\uc0\\u233{} et al., 2015; Ferry, Morneau, Bontemps, Blanc, & Freycon, 2010)","plainCitation":"(Allié et al., 2015; Ferry, Morneau, Bontemps, Blanc, & Freycon, 2010)","noteIndex":0},"citationItems":[{"id":"fCAS7BvH/fnAXPCPt","uris":["http://zotero.org/users/local/9u60twst/items/DUQQZTTY"],"uri":["http://zotero.org/users/local/9u60twst/items/DUQQZTTY"],"itemData":{"id":1097,"type":"article-journal","title":"Higher treefall rates on slopes and waterlogged soils result in lower stand biomass and productivity in a tropical rain forest","container-title":"Journal of Ecology","page":"106-116","volume":"98","issue":"1","source":"Wiley Online Library","abstract":"1. Relationships between tropical rain forest biomass and environmental factors have been determined at regional scales, e.g. the Amazon Basin, but the reasons for the high variability in forest biomass at local scales are poorly understood. Interactions between topography, soil properties, tree growth and mortality rates, and treefalls are a likely reason for this variability. 2. We used repeated measurements of permanent plots in lowland rain forest in French Guiana to evaluate these relationships. The plots sampled topographic gradients from hilltops to slopes to bottomlands, with accompanying variation in soil waterlogging along these gradients. Biomass was calculated for >175 tree species in the plots, along with biomass productivity and recruitment rates. Mortality was determined as standing dead and treefalls. 3. Treefall rates were twice as high in bottomlands as on hilltops, and tree recruitment rates, radial growth rates and the abundance of light-demanding tree species were also higher. 4. In the bottomlands, the mean wood density was 10% lower than on hilltops, the basal area 29% lower and the height:diameter ratio of trees was lower, collectively resulting in a total woody biomass that was 43% lower in bottomlands than on hilltops. 5. Biomass productivity was 9% lower in bottomlands than on hilltops, even though soil Olsen P concentrations were higher in bottomlands. 6. Synthesis. Along a topographic gradient from hilltops to bottomlands there were higher rates of treefall, which decreased the stand basal area and favoured lower allocation to height growth and recruitment of light-demanding species with low wood density. The resultant large variation in tree biomass along the gradient shows the importance of determining site characteristics and including these characteristics when scaling up biomass estimates from stand to local or regional scales.","DOI":"10.1111/j.1365-2745.2009.01604.x","ISSN":"1365-2745","language":"en","author":[{"family":"Ferry","given":"Bruno"},{"family":"Morneau","given":"François"},{"family":"Bontemps","given":"Jean-Daniel"},{"family":"Blanc","given":"Lilian"},{"family":"Freycon","given":"Vincent"}],"issued":{"date-parts":[["2010",1,1]]}}},{"id":"fCAS7BvH/k4bf7z7I","uris":["http://zotero.org/users/local/9u60twst/items/UBBR8XQF"],"uri":["http://zotero.org/users/local/9u60twst/items/UBBR8XQF"],"itemData":{"id":419,"type":"article-journal","title":"Pervasive Local-Scale Tree-Soil Habitat Association in a Tropical Forest Community","container-title":"PLOS ONE","page":"e0141488","volume":"10","issue":"11","source":"journals.plos.org","abstract":"We examined tree-soil habitat associations in lowland forest communities at Paracou, French Guiana. We analyzed a large dataset assembling six permanent plots totaling 37.5 ha, in which extensive LIDAR-derived topographical data and soil chemical and physical data have been integrated with precise botanical determinations. Map of relative elevation from the nearest stream summarized both soil fertility and hydromorphic characteristics, with seasonally inundated bottomlands having higher soil phosphate content and base saturation, and plateaus having higher soil carbon, nitrogen and aluminum contents. We employed a statistical test of correlations between tree species density and environmental maps, by generating Monte Carlo simulations of random raster images that preserve autocorrelation of the original maps. Nearly three fourths of the 94 taxa with at least one stem per ha showed a significant correlation between tree density and relative elevation, revealing contrasted species-habitat associations in term of abundance, with seasonally inundated bottomlands (24.5% of species) and well-drained plateaus (48.9% of species). We also observed species preferences for environments with or without steep slopes (13.8% and 10.6%, respectively). We observed that closely-related species were frequently associated with different soil habitats in this region (70% of the 14 genera with congeneric species that have a significant association test) suggesting species-habitat associations have arisen multiple times in this tree community. We also tested if species with similar habitat preferences shared functional strategies. We found that seasonally inundated forest specialists tended to have smaller stature (maximum diameter) than species found on plateaus. Our results underline the importance of tree-soil habitat associations in structuring diverse communities at fine spatial scales and suggest that additional studies are needed to disentangle community assembly mechanisms related to dispersal limitation, biotic interactions and environmental filtering from species-habitat associations. Moreover, they provide a framework to generalize across tropical forest sites.","DOI":"10.1371/journal.pone.0141488","ISSN":"1932-6203","journalAbbreviation":"PLOS ONE","author":[{"family":"Allié","given":"Elodie"},{"family":"Pélissier","given":"Raphaël"},{"family":"Engel","given":"Julien"},{"family":"Petronelli","given":"Pascal"},{"family":"Freycon","given":"Vincent"},{"family":"Deblauwe","given":"Vincent"},{"family":"Soucémarianadin","given":"Laure"},{"family":"Weigel","given":"Jean"},{"family":"Baraloto","given":"Christopher"}],"issued":{"date-parts":[["2015",11,4]]}}}],"schema":"https://github.com/citation-style-language/schema/raw/master/csl-citation.json"} (Allié et al., 2015; Ferry, Morneau, Bontemps, Blanc, & Freycon, 2010). Hilltop-bottomland heterogeneity impacts species distribution ADDIN ZOTERO_ITEM CSL_CITATION {"citationID":"a2mfokbo00l","properties":{"formattedCitation":"(Clark et al., 1999; P\\uc0\\u233{}lissier et al., 2002; Sabatier et al., 1997; ter Steege et al., 1993)","plainCitation":"(Clark et al., 1999; Pélissier et al., 2002; Sabatier et al., 1997; ter Steege et al., 1993)","noteIndex":0},"citationItems":[{"id":"fCAS7BvH/MZANwc2D","uris":["http://zotero.org/users/local/9u60twst/items/AWF2KNCQ"],"uri":["http://zotero.org/users/local/9u60twst/items/AWF2KNCQ"],"itemData":{"id":1078,"type":"article-journal","title":"Tropical rain forest types and soil factors in a watershed area in Guyana","container-title":"Journal of Vegetation Science","page":"705-716","volume":"4","issue":"5","source":"Wiley Online Library","abstract":"Abstract. An inventory was made of the vegetation and soils of a watershed area of 480 ha in the tropical rain forest of Guyana. 252 plots of 0.05 ha were sampled. In total 111 tree species > 20 cm were recorded. A TWINSPAN analysis resulted in seven groupings. Correspondence Analysis revealed that the major environmental differentiation underlying the floristic variation is according to soil type. Finally, five main forest communities were described. Most sites in the watershed area are characterized by the dominance of one or a few species. Species distribution patterns are strongly determined by soil type and drainage class.","DOI":"10.2307/3236137","ISSN":"1654-1103","language":"en","author":[{"family":"Steege","given":"Hans","non-dropping-particle":"ter"},{"family":"Jetten","given":"Victor G."},{"family":"Polak","given":"A. Marcel"},{"family":"Werger","given":"Marinus J. A."}],"issued":{"date-parts":[["1993",10,1]]}}},{"id":"fCAS7BvH/3dWgyefj","uris":["http://zotero.org/users/local/9u60twst/items/3NDUDEIV"],"uri":["http://zotero.org/users/local/9u60twst/items/3NDUDEIV"],"itemData":{"id":807,"type":"article-journal","title":"The influence of soil cover organization on the floristic and structural heterogeneity of a Guianan rain forest","container-title":"Plant Ecology","page":"81-108","volume":"131","issue":"1","source":"link.springer.com","abstract":"The impact of soil cover organization on the forest community has been studied in a 19-ha tract at Piste de St Elie station in French Guiana. 195 species each represented by at least 10 individuals we","DOI":"10.1023/A:1009775025850","ISSN":"1385-0237, 1573-5052","journalAbbreviation":"Plant Ecology","language":"en","author":[{"family":"Sabatier","given":"Daniel"},{"family":"Grimaldi","given":"Michel"},{"family":"Prévost","given":"Marie-Françoise"},{"family":"Guillaume","given":"Julie"},{"family":"Godron","given":"Michel"},{"family":"Dosso","given":"Mireille"},{"family":"Curmi","given":"Pierre"}],"issued":{"date-parts":[["1997",7,1]]}}},{"id":"fCAS7BvH/Kk0eevfl","uris":["http://zotero.org/users/local/9u60twst/items/78KUNJX6"],"uri":["http://zotero.org/users/local/9u60twst/items/78KUNJX6"],"itemData":{"id":1080,"type":"article-journal","title":"Edaphic Factors and the Landscape-Scale Distributions of Tropical Rain Forest Trees","container-title":"Ecology","page":"2662-2675","volume":"80","issue":"8","source":"Wiley Online Library","abstract":"Tropical rain forests have the highest tree diversity on earth. Nonrandom spatial distributions of these species in relation to edaphic factors could be one mechanism responsible for maintaining this diversity. We examined the prevalence of nonrandom distributions of trees and palms in relation to soil type and topographic position (“edaphic biases”) over a mesoscale (573 ha) old-growth tropical rain forest (TRF) landscape at the La Selva Biological Station, Costa Rica. All trees and palms ≥10 cm diameter were measured and identified in 1170 circular 0.01-ha plots centered on an existing 50 × 100 m grid. Topographic position was classified for each plot, and slope and aspect were measured. Soil type data were taken from a previous study (Clark et al. 1998). A total of 5127 trees and palms were identified in 267 species. Detrended Correspondence Analysis and Canonical Correspondence Analysis showed that highly significant edaphic gradients were present, with swamp or highly fertile soils separated from the less fertile, well-drained upland soils. Species composition remained significantly related to topographic position when soil type was controlled for. The main floristic gradients were still significant when flooded sites were excluded from the analyses. Randomization tests on a weighted preference index were used to examine the relations of individual species to soil types and, within the dominant soil type, to topographic position. Of the 132 species with N ≥ 5 individuals, 33 showed significant associations with soil type. Within the dominant soil type, 13 of 110 analyzable species were nonrandomly associated with one or more topographic positions. For a variety of reasons, including issues relating to sample size and adequate edaphic characterization of landscapes, we suggest that the ∼30% of species shown to be edaphically biased in this study is an underestimate of the true degree of edaphically related distributional biases. To evaluate this hypothesis will require mesoscale vegetation sampling combined with quantitative soil analyses at the same scale in a range of tropical rain forests. If edaphic distributional biases are shown to be common, this suggests that edaphically linked processes leading to differential recruitment are similarly common.","DOI":"10.1890/0012-9658(1999)080[2662:EFATLS]2.0.CO;2","ISSN":"1939-9170","language":"en","author":[{"family":"Clark","given":"David B."},{"family":"Palmer","given":"Michael W."},{"family":"Clark","given":"Deborah A."}],"issued":{"date-parts":[["1999",12,1]]}}},{"id":"fCAS7BvH/cz3CPtBx","uris":["http://zotero.org/users/local/9u60twst/items/Q68CN6T9"],"uri":["http://zotero.org/users/local/9u60twst/items/Q68CN6T9"],"itemData":{"id":113,"type":"article-journal","title":"Within-Plot Relationships between Tree Species Occurrences and Hydrological Soil Constraints: An Example in French Guiana Investigated through Canonical Correlation Analysis","container-title":"Plant Ecology","page":"143-156","volume":"162","issue":"2","source":"JSTOR","abstract":"Spatial relationships between tree species and hydrological soil constraints are analysed within a 10-ha rainforest plot at Piste de St Elie in French Guiana. We used canonical correlation analysis to cross directly the occurrence-by-species table of 4 992 individuals (d.b.h. ≥ 10 cm) belonging to 120 species with qualitative soil variables and quantitative spatial data. Firstly, the list of species occurrences was confronted to nine soil descriptors characterising a weathering sequence from the initial well-drained ferralitic cover to transformed hydromorphic soil conditions. This analysis revealed that, apart from some specialised species restricted to the swamps that experience prolonged water saturation, the most abundant species can be ordered along two intermingled gradients of tolerance limiting their niche amplitude: a main gradient of tolerance to prolonged water saturation that appears down slope during the weathering sequence; a second gradient of less importance, displaying the species intolerant of prolonged water saturation according to their tolerance to temporary confinement of the uphill transformed soil systems due to the late appearance of a perched water-table. The results support the hypothesis that at Piste de St Elie, the constraining soil conditions imposed by surface water saturation are more important determinants for tree zonation of many tree species than water shortage. Secondly, the list of species occurrences was confronted to a spatial data table built from a trend surface regression of the tree coordinates. This analysis indicated that soil drainage is the main structuring factor of the local multispecies spatial pattern. After partialling out the soil effect, the multispecies pattern revealed a broader scale of heterogeneity that we supposed to be linked to endogenous factors resulting from population dynamics. Implications of the results are then discussed in the perspective of future research on tree zonation, local diversity pattern and community structuring in tropical rainforests.","ISSN":"1385-0237","shortTitle":"Within-Plot Relationships between Tree Species Occurrences and Hydrological Soil Constraints","journalAbbreviation":"Plant Ecology","author":[{"family":"Pélissier","given":"Raphaël"},{"family":"Dray","given":"Stéphane"},{"family":"Sabatier","given":"Daniel"}],"issued":{"date-parts":[["2002"]]}}}],"schema":"https://github.com/citation-style-language/schema/raw/master/csl-citation.json"} (Clark et al., 1999; Pélissier et al., 2002; Sabatier et al., 1997; ter Steege et al., 1993), for which strong species-specific habitat preferences have been shown ADDIN ZOTERO_ITEM CSL_CITATION {"citationID":"a2glm4br8mi","properties":{"formattedCitation":"(Alli\\uc0\\u233{} et al., 2015)","plainCitation":"(Allié et al., 2015)","noteIndex":0},"citationItems":[{"id":"fCAS7BvH/k4bf7z7I","uris":["http://zotero.org/users/local/9u60twst/items/UBBR8XQF"],"uri":["http://zotero.org/users/local/9u60twst/items/UBBR8XQF"],"itemData":{"id":419,"type":"article-journal","title":"Pervasive Local-Scale Tree-Soil Habitat Association in a Tropical Forest Community","container-title":"PLOS ONE","page":"e0141488","volume":"10","issue":"11","source":"journals.plos.org","abstract":"We examined tree-soil habitat associations in lowland forest communities at Paracou, French Guiana. We analyzed a large dataset assembling six permanent plots totaling 37.5 ha, in which extensive LIDAR-derived topographical data and soil chemical and physical data have been integrated with precise botanical determinations. Map of relative elevation from the nearest stream summarized both soil fertility and hydromorphic characteristics, with seasonally inundated bottomlands having higher soil phosphate content and base saturation, and plateaus having higher soil carbon, nitrogen and aluminum contents. We employed a statistical test of correlations between tree species density and environmental maps, by generating Monte Carlo simulations of random raster images that preserve autocorrelation of the original maps. Nearly three fourths of the 94 taxa with at least one stem per ha showed a significant correlation between tree density and relative elevation, revealing contrasted species-habitat associations in term of abundance, with seasonally inundated bottomlands (24.5% of species) and well-drained plateaus (48.9% of species). We also observed species preferences for environments with or without steep slopes (13.8% and 10.6%, respectively). We observed that closely-related species were frequently associated with different soil habitats in this region (70% of the 14 genera with congeneric species that have a significant association test) suggesting species-habitat associations have arisen multiple times in this tree community. We also tested if species with similar habitat preferences shared functional strategies. We found that seasonally inundated forest specialists tended to have smaller stature (maximum diameter) than species found on plateaus. Our results underline the importance of tree-soil habitat associations in structuring diverse communities at fine spatial scales and suggest that additional studies are needed to disentangle community assembly mechanisms related to dispersal limitation, biotic interactions and environmental filtering from species-habitat associations. Moreover, they provide a framework to generalize across tropical forest sites.","DOI":"10.1371/journal.pone.0141488","ISSN":"1932-6203","journalAbbreviation":"PLOS ONE","author":[{"family":"Allié","given":"Elodie"},{"family":"Pélissier","given":"Raphaël"},{"family":"Engel","given":"Julien"},{"family":"Petronelli","given":"Pascal"},{"family":"Freycon","given":"Vincent"},{"family":"Deblauwe","given":"Vincent"},{"family":"Soucémarianadin","given":"Laure"},{"family":"Weigel","given":"Jean"},{"family":"Baraloto","given":"Christopher"}],"issued":{"date-parts":[["2015",11,4]]}}}],"schema":"https://github.com/citation-style-language/schema/raw/master/csl-citation.json"} (Allié et al., 2015). Evidence for directional across-community differences in functional traits underlying such spatial patterns is also accruing ADDIN ZOTERO_ITEM CSL_CITATION {"citationID":"ab81aftjt5","properties":{"formattedCitation":"(Cosme, Schietti, Costa, & Oliveira, 2017; Engelbrecht et al., 2007; Fortunel, Paine, Fine, Kraft, & Baraloto, 2014; Fortunel, Ruelle, Beauch\\uc0\\u234{}ne, Fine, & Baraloto, 2014; Lopez & Kursar, 2003)","plainCitation":"(Cosme, Schietti, Costa, & Oliveira, 2017; Engelbrecht et al., 2007; Fortunel, Paine, Fine, Kraft, & Baraloto, 2014; Fortunel, Ruelle, Beauchêne, Fine, & Baraloto, 2014; Lopez & Kursar, 2003)","noteIndex":0},"citationItems":[{"id":"fCAS7BvH/gvuH2eFk","uris":["http://zotero.org/users/local/9u60twst/items/G537XD3Z"],"uri":["http://zotero.org/users/local/9u60twst/items/G537XD3Z"],"itemData":{"id":805,"type":"article-journal","title":"Does Flood Tolerance Explain Tree Species Distribution in Tropical Seasonally Flooded Habitats?","container-title":"Oecologia","page":"193-204","volume":"136","issue":"2","source":"JSTOR","abstract":"In the tropics, seasonally flooded forests (SFF) harbor fewer tree species than terra firme (i.e. nonflooded) forests. The low species diversity of tropical flooded forests has been ascribed to the paucity of species with adaptations to tolerate flooding. To test the hypothesis that flooding is the only factor restricting most species from SFF, we compared plant morphological and physiological responses to flooding in 2-month old seedlings of 6 species common to SFF and 12 species common to terra firme forests. Although flooding impaired growth, total biomass, maximum root length and stomatal conductance in most species, responses varied greatly and were species-specific. For example, after 90 days, flooding reduced leaf area growth by 10-50% in all species, except in Tabebuia, a common species from non-flooded habitats. Similarly, flooding had a 5-45% negative effect on total biomass for all species, except in 1 SFF and 1 terra firme species both of which had more biomass under flooding. A principal component analysis, using the above responses to flooding, provided no evidence that SFF and terra firme species differed in their responses to flooding. Flooding also caused reductions in root growth for most species. Rooting depth and root: shoot ratios were significantly less affected by flooding in SFF than in terra firme species. Although flood tolerance is critical for survival in flooded habitats, we hypothesize that responses to post-flooding events such as drought might be equally important in seasonal habitats. Therefore, we suggest that the ability to grow roots under anoxia might be critical in predicting success in inundated habitats that also experience a strong dry season.","ISSN":"0029-8549","author":[{"family":"Lopez","given":"Omar R."},{"family":"Kursar","given":"Thomas A."}],"issued":{"date-parts":[["2003"]]}}},{"id":"fCAS7BvH/WFuAk3kE","uris":["http://zotero.org/users/local/9u60twst/items/WZXJVPCZ"],"uri":["http://zotero.org/users/local/9u60twst/items/WZXJVPCZ"],"itemData":{"id":800,"type":"article-journal","title":"Drought sensitivity shapes species distribution patterns in tropical forests","container-title":"Nature","page":"80-82","volume":"447","issue":"7140","source":"www.nature.com","abstract":"Nature is the international weekly journal of science: a magazine style journal that publishes full-length research papers in all disciplines of science, as well as News and Views, reviews, news, features, commentaries, web focuses and more, covering all branches of science and how science impacts upon all aspects of society and life.","DOI":"10.1038/nature05747","ISSN":"0028-0836","language":"en","author":[{"family":"Engelbrecht","given":"Bettina M. J."},{"family":"Comita","given":"Liza S."},{"family":"Condit","given":"Richard"},{"family":"Kursar","given":"Thomas A."},{"family":"Tyree","given":"Melvin T."},{"family":"Turner","given":"Benjamin L."},{"family":"Hubbell","given":"Stephen P."}],"issued":{"date-parts":[["2007",5,3]]}}},{"id":"fCAS7BvH/vwezMf1Z","uris":["http://zotero.org/users/local/9u60twst/items/E8JP2BIG"],"uri":["http://zotero.org/users/local/9u60twst/items/E8JP2BIG"],"itemData":{"id":1112,"type":"article-journal","title":"Environmental factors predict community functional composition in Amazonian forests","container-title":"Journal of Ecology","page":"145-155","volume":"102","issue":"1","source":"Wiley Online Library","abstract":"* The consequences of biodiversity loss for ecosystem services largely depend on the functional identities of extirpated species. However, poor descriptions of spatial patterns of community functional composition across landscapes hamper accurate predictions, particularly in highly diverse tropical regions. Therefore, understanding how community functional composition varies across environmental gradients remains an important challenge.\n\n\n* We sampled 15 functional traits in 800 Neotropical tree species across 13 forest plots representative of the broad climatic and soil gradients encompassed by three widespread lowland forest habitats (terra firme forests on clay-rich soils, seasonally flooded forests and white-sand forests) at opposite ends of Amazonia (Peru and French Guiana). We combined univariate and multivariate approaches to test the magnitude and predictability of environmental filtering on community leaf and wood functional composition.\n\n\n* Directional shifts in community functional composition correlated with environmental changes across the 13 plots, with denser leaves, stems and roots in forests occurring in environments with limited water and soil-nutrient availability. Critically, these relationships allowed us to accurately predict the functional composition of 61 additional forest plots from environmental data alone.\n\n\n* Synthesis. Environmental filtering consistently shapes the functional composition of highly diverse tropical forests at large scales across the terra firme, seasonally flooded and white-sand forests of lowland Amazonia. Environmental factors drive and allow the prediction of variation in community functional composition among habitat types in Amazonian forests.","DOI":"10.1111/1365-2745.12160","ISSN":"1365-2745","journalAbbreviation":"J Ecol","language":"en","author":[{"family":"Fortunel","given":"Claire"},{"family":"Paine","given":"C. E. Timothy"},{"family":"Fine","given":"Paul V. A."},{"family":"Kraft","given":"Nathan J. B."},{"family":"Baraloto","given":"Christopher"}],"issued":{"date-parts":[["2014",1,1]]}}},{"id":"fCAS7BvH/4NJTfy4g","uris":["http://zotero.org/users/local/9u60twst/items/BH9JZ7GQ"],"uri":["http://zotero.org/users/local/9u60twst/items/BH9JZ7GQ"],"itemData":{"id":163,"type":"article-journal","title":"Wood specific gravity and anatomy of branches and roots in 113 Amazonian rainforest tree species across environmental gradients","container-title":"New Phytologist","page":"79-94","volume":"202","issue":"1","source":"Wiley Online Library","abstract":"* Wood specific gravity (WSG) is a strong predictor of tree performance across environmental gradients. Yet it remains unclear how anatomical elements linked to different wood functions contribute to variation in WSG in branches and roots across tropical forests.\n\n\n* We examined WSG and wood anatomy in white sand, clay terra firme and seasonally flooded forests in French Guiana, spanning broad environmental gradients found throughout Amazonia. We measured 15 traits relating to branches and small woody roots in 113 species representing the 15 most abundant species in each habitat and representative species from seven monophyletic lineages occurring in all habitats.\n\n\n* Fiber traits appear to be major determinants of WSG, independent of vessel traits, in branches and roots. Fiber traits and branch and root WSG increased from seasonally flooded species to clay terra firme species and lastly to white sand species. Branch and root wood traits were strongly phylogenetically constrained. Lineages differed in wood design, but exhibited similar variation in wood structure across habitats.\n\n\n* We conclude that tropical trees can invest differently in support and transport to respond to environmental conditions. Wind disturbance and drought stress represent significant filters driving tree distribution of Amazonian forests; hence we suggest that biophysical explanations should receive more attention.","DOI":"10.1111/nph.12632","ISSN":"1469-8137","journalAbbreviation":"New Phytol","language":"en","author":[{"family":"Fortunel","given":"Claire"},{"family":"Ruelle","given":"Julien"},{"family":"Beauchêne","given":"Jacques"},{"family":"Fine","given":"Paul V. A."},{"family":"Baraloto","given":"Christopher"}],"issued":{"date-parts":[["2014",4,1]]}}},{"id":"fCAS7BvH/8m0mODaU","uris":["http://zotero.org/users/local/9u60twst/items/CHA9MMM3"],"uri":["http://zotero.org/users/local/9u60twst/items/CHA9MMM3"],"itemData":{"id":1100,"type":"article-journal","title":"The importance of hydraulic architecture to the distribution patterns of trees in a central Amazonian forest","container-title":"New Phytologist","page":"113-125","volume":"215","issue":"1","source":"Wiley Online Library","abstract":"* Species distributions and assemblage composition may be the result of trait selection through environmental filters. Here, we ask whether filtering of species at the local scale could be attributed to their hydraulic architectural traits, revealing the basis of hydrological microhabitat partitioning in a Central Amazonian forest.\n\n\n* We analyzed the hydraulic characteristics at tissue (anatomical traits, wood specific gravity (WSG)), organ (leaf area, specific leaf area (SLA), leaf area : sapwood area ratio) and whole-plant (height) levels for 28 pairs of congeneric species from 14 genera restricted to either valleys or plateaus of a terra-firme forest in Central Amazonia.\n\n\n* On plateaus, species had higher WSG, but lower mean vessel area, mean vessel hydraulic diameter, sapwood area and SLA than in valleys; traits commonly associated with hydraulic safety. Mean vessel hydraulic diameter and mean vessel area increased with height for both habitats, but leaf area and leaf area : sapwood area ratio investments with tree height declined in valley vs plateau species. [Correction added after online publication 29 March 2017: the preceding sentence has been reworded.] Two strategies for either efficiency or safety were detected, based on vessel size or allocation to sapwood.\n\n\n* In conclusion, contrasting hydrological conditions act as environmental filters, generating differences in species composition at the local scale. This has important implications for the prediction of species distributions under future climate change scenarios.","DOI":"10.1111/nph.14508","ISSN":"1469-8137","journalAbbreviation":"New Phytol","language":"en","author":[{"family":"Cosme","given":"Luiza H. M."},{"family":"Schietti","given":"Juliana"},{"family":"Costa","given":"Flávia R. C."},{"family":"Oliveira","given":"Rafael S."}],"issued":{"date-parts":[["2017",7,1]]}}}],"schema":"https://github.com/citation-style-language/schema/raw/master/csl-citation.json"} (Cosme, Schietti, Costa, & Oliveira, 2017; Engelbrecht et al., 2007; Fortunel, Paine, Fine, Kraft, & Baraloto, 2014; Fortunel, Ruelle, Beauchêne, Fine, & Baraloto, 2014; Lopez & Kursar, 2003). Comment by Seb L.: Georges Kunstler:Delete “across-community” and replace by interspecificComment by Seb L.: This point has been abandoned for the new version of the manuscript.

The Amazon rainforest has been a rich study field for investigating key questions on trait-based ecology, such as relationships of functional traits with environmental gradients (Kraft et al. 2008). Edaphic gradients have been particularly studied to disentangle drivers of spatial distribution of species and functional traits over the Amazon basin (Sabatier et al. 1997; Clark et al. 1999; Stropp et al. 2011; Allié et al. 2015).Second, tThe contrast between white-sand (WS) versus ferralitic soils (FS) has been repeatedly used for explaining Amazonian spatial species diversity turnover. WS are mainly quartz soils, representing 3% to 5% of soils in the Amazon basin and exist as island-like spots in a matrix of other soils such as FS ADDIN ZOTERO_ITEM CSL_CITATION {"citationID":"a10qukmuuoq","properties":{"formattedCitation":"(Adeney {\\i{}et al.} 2016; Fine and Baraloto 2016a)","plainCitation":"(Adeney et al. 2016; Fine and Baraloto 2016a)","noteIndex":0},"citationItems":[{"id":"fCAS7BvH/yDWwQwwq","uris":["http://zotero.org/users/local/9u60twst/items/Q4MVFSKK"],"uri":["http://zotero.org/users/local/9u60twst/items/Q4MVFSKK"],"itemData":{"id":1106,"type":"article-journal","title":"White-sand Ecosystems in Amazonia","container-title":"Biotropica","page":"7-23","volume":"48","issue":"1","source":"Wiley Online Library","abstract":"Vegetation on sandy soils, ranging from open grasslands and shrublands to closed-canopy, thin-trunked forests, can be found in patches throughout the Amazon. Despite variation in names, appearance, ecological correlates, and suggested origins, these ‘white-sand ecosystems’ (WSE) share distinctive characteristics and biological communities. Here, in the first Amazon-wide review of WSE, we review the variation in WSE and the factors underlying this variation. We present the most comprehensive Amazon-wide map to date of WSE and calculate their total area. We find that WSE are still not completely mapped, and we use biological correlates as a proxy to indicate where white-sand vegetation patches likely occur. Through our synthesis of the literature, we find that key factors, such as geologic origin, soil characteristics, hydrology, and fire regimes, vary widely and have differing impacts in different regions on vegetation structure and on floral, faunal, and fungal species composition. Although studies of WSE have increased dramatically in recent years, WSE in many parts of the Amazon remain understudied, and there is little synthesis of the interaction of factors across different areas. In response, we suggest priorities for future research. Finally, we find that WSE are inadequately protected and, where accessible, are regularly mined for sand, logged, or burned and cleared for agriculture. We argue that due to their island-like distribution patterns and resultant complex metapopulation dynamics, their extremely slow recovery after disturbance, and their important contributions to basin-wide diversity patterns and ecosystem services, WSE should be given special consideration in conservation efforts to ensure their persistence in Amazonia.","DOI":"10.1111/btp.12293","ISSN":"1744-7429","journalAbbreviation":"Biotropica","language":"en","author":[{"family":"Adeney","given":"J. Marion"},{"family":"Christensen","given":"Norman L."},{"family":"Vicentini","given":"Alberto"},{"family":"Cohn-Haft","given":"Mario"}],"issued":{"date-parts":[["2016",1,1]]}}},{"id":"fCAS7BvH/lCsD8OjK","uris":["http://zotero.org/users/local/9u60twst/items/549RPK5X"],"uri":["http://zotero.org/users/local/9u60twst/items/549RPK5X"],"itemData":{"id":1104,"type":"article-journal","title":"Habitat Endemism in White-sand Forests: Insights into the Mechanisms of Lineage Diversification and Community Assembly of the Neotropical Flora","container-title":"Biotropica","page":"24-33","volume":"48","issue":"1","source":"Wiley Online Library","abstract":"White-sand forests represent natural laboratories of evolution over their long history throughout Amazonia and the Guiana Shield and pose significant physiological challenges to the plants and animals they host. The study of diversification in plant lineages comprising species endemic to white-sand forest can therefore give insights into processes of evolution and community assembly in tropical forests. In this article, we synthesize recent studies of white-sand forests to integrate patterns of plant species distribution with processes of lineage diversification and community assembly in the white-sand flora. We contrast lineages that have radiated uniquely in these habitats (e.g., Pagamea, Rubiaceae), with cosmopolitan lineages comprising specialists to white-sand forests and other habitats that may have arisen via ecological speciation across habitat gradients (e.g., Protium, Burseraceae). In both cases, similar suites of functional traits have evolved, including investment in dense, long-lived tissues that are well-defended structurally and chemically. White-sand endemics, therefore, play an important role in biodiversity conservation because they represent unique combinations of functional and phylogenetic diversity. Furthermore, white-sand endemics may respond differently than other tropical forest plant species to contemporary global changes because they comprise resilient functional types that may better withstand increased drought, temperature, and invasions of exotic pests in these regions.","DOI":"10.1111/btp.12301","ISSN":"1744-7429","shortTitle":"Habitat Endemism in White-sand Forests","journalAbbreviation":"Biotropica","language":"en","author":[{"family":"Fine","given":"Paul V. A."},{"family":"Baraloto","given":"Christopher"}],"issued":{"date-parts":[["2016",1,1]]}}}],"schema":"https://github.com/citation-style-language/schema/raw/master/csl-citation.json"} (Adeney et al. 2016; Fine and Baraloto 2016). Generally, WS are poor in mineral nutrients and acidic, with low-usable water reserves and poor nitrogen mineralization, especially in comparison with common FS. Similar to the hilltop-plateau contrast, The environmental filtering ensued by the FS-WS heterogeneity has strong impacts on species distribution patterns at the community level ADDIN ZOTERO_ITEM CSL_CITATION {"citationID":"Tz7kBWOo","properties":{"formattedCitation":"(Stropp {\\i{}et al.} 2011; ter Steege {\\i{}et al.} 2013; Daly {\\i{}et al.} 2016; Fine and Baraloto 2016a)","plainCitation":"(Stropp et al. 2011; ter Steege et al. 2013; Daly et al. 2016; Fine and Baraloto 2016a)","noteIndex":0},"citationItems":[{"id":"fCAS7BvH/EwaGZnxd","uris":["http://zotero.org/users/local/9u60twst/items/PW86RQW8"],"uri":["http://zotero.org/users/local/9u60twst/items/PW86RQW8"],"itemData":{"id":1087,"type":"article-journal","title":"Tree communities of white-sand and terra-firme forests of the upper Rio Negro","container-title":"Acta Amazonica","page":"521-544","volume":"41","issue":"4","source":"SciELO","DOI":"10.1590/S0044-59672011000400010","ISSN":"0044-5967","author":[{"family":"Stropp","given":"Juliana"},{"family":"Sleen","given":"Peter Van","dropping-particle":"der"},{"family":"Assunção","given":"Paulo Apóstolo"},{"family":"Silva","given":"Adeilson Lopes","dropping-particle":"da"},{"family":"Steege","given":"Hans Ter"}],"issued":{"date-parts":[["2011"]]}}},{"id":"fCAS7BvH/zQ8TJ4Eb","uris":["http://zotero.org/users/local/9u60twst/items/R7CZRGUG"],"uri":["http://zotero.org/users/local/9u60twst/items/R7CZRGUG"],"itemData":{"id":94,"type":"article-journal","title":"Hyperdominance in the Amazonian Tree Flora","container-title":"Science","page":"1243092","volume":"342","issue":"6156","source":"www.sciencemag.org","abstract":"Structured Abstract\nIntroduction Recent decades have seen a major international effort to inventory tree communities in the Amazon Basin and Guiana Shield (Amazonia), but the vast extent and record diversity of these forests have hampered an understanding of basinwide patterns. To overcome this obstacle, we compiled and standardized species-level data on more than half a million trees in 1170 plots sampling all major lowland forest types to explore patterns of commonness, rarity, and richness.\nA map of Amazonia showing the location of the 1430 Amazon Tree Diversity Network (ATDN) plots that contributed data to this paper. The white polygon marks our delimitation of the study area and consists of 567 1° grid cells (area = 6.29 million km2). Orange circles indicate plots on terra firme; blue squares, plots on seasonally or permanently flooded terrain (várzea, igapó, swamps); yellow triangles, plots on white-sand podzols; gray circles, plots only used for tree density calculations. Background is from Visible Earth. CA, central Amazonia; EA, eastern Amazonia; GS, Guyana Shield; SA, southern Amazonia; WAN, northern part of western Amazonia; WAS, southern part of western Amazonia. More details are shown in figs. S1 to S3.\nMethods The ~6-million-km2 Amazonian lowlands were divided into 1° cells, and mean tree density was estimated for each cell by using a loess regression model that included no environmental data but had its basis exclusively in the geographic location of tree plots. A similar model, allied with a bootstrapping exercise to quantify sampling error, was used to generate estimated Amazon-wide abundances of the 4962 valid species in the data set. We estimated the total number of tree species in the Amazon by fitting the mean rank-abundance data to Fisher’s log-series distribution.\nResults Our analyses suggest that lowland Amazonia harbors 3.9 × 1011 trees and ~16,000 tree species. We found 227 “hyperdominant” species (1.4% of the total) to be so common that together they account for half of all trees in Amazonia, whereas the rarest 11,000 species account for just 0.12% of trees. Most hyperdominants are habitat specialists that have large geographic ranges but are only dominant in one or two regions of the basin, and a median of 41% of trees in individual plots belong to hyperdominants. A disproportionate number of hyperdominants are palms, Myristicaceae, and Lecythidaceae.\nDiscussion The finding that Amazonia is dominated by just 227 tree species implies that most biogeochemical cycling in the world’s largest tropical forest is performed by a tiny sliver of its diversity. The causes underlying hyperdominance in these species remain unknown. Both competitive superiority and widespread pre-1492 cultivation by humans are compelling hypotheses that deserve testing. Although the data suggest that spatial models can effectively forecast tree community composition and structure of unstudied sites in Amazonia, incorporating environmental data may yield substantial improvements. An appreciation of how thoroughly common species dominate the basin has the potential to simplify research in Amazonian biogeochemistry, ecology, and vegetation mapping. Such advances are urgently needed in light of the >10,000 rare, poorly known, and potentially threatened tree species in the Amazon.\nSeeing the Trees in the Forest\nDespite botanical exploration over two centuries, knowledge of the species composition and quantitative distribution of the trees of the Amazonian forest has remained decidedly patchy. Ter Steege et al. (1243092) report the results from a network of 1170 tree plots arrayed across the Amazon Basin and Guiana Shield, in which the species of all trees with stem diameter >10 centimeters were identified. The tree flora comprised a total of about 16,000 species. However, just 227 very common Amazonian species accounted for half of the trees in the Amazon—the world's most diverse forest.\nThe vast extent of the Amazon Basin has historically restricted the study of its tree communities to the local and regional scales. Here, we provide empirical data on the commonness, rarity, and richness of lowland tree species across the entire Amazon Basin and Guiana Shield (Amazonia), collected in 1170 tree plots in all major forest types. Extrapolations suggest that Amazonia harbors roughly 16,000 tree species, of which just 227 (1.4%) account for half of all trees. Most of these are habitat specialists and only dominant in one or two regions of the basin. We discuss some implications of the finding that a small group of species—less diverse than the North American tree flora—accounts for half of the world’s most diverse tree community.","DOI":"10.1126/science.1243092","ISSN":"0036-8075, 1095-9203","note":"PMID: 24136971","journalAbbreviation":"Science","language":"en","author":[{"family":"Steege","given":"Hans","non-dropping-particle":"ter"},{"family":"Pitman","given":"Nigel C. A."},{"family":"Sabatier","given":"Daniel"},{"family":"Baraloto","given":"Christopher"},{"family":"Salomão","given":"Rafael P."},{"family":"Guevara","given":"Juan Ernesto"},{"family":"Phillips","given":"Oliver L."},{"family":"Castilho","given":"Carolina V."},{"family":"Magnusson","given":"William E."},{"family":"Molino","given":"Jean-François"},{"family":"Monteagudo","given":"Abel"},{"family":"Vargas","given":"Percy Núñez"},{"family":"Montero","given":"Juan Carlos"},{"family":"Feldpausch","given":"Ted R."},{"family":"Coronado","given":"Eurídice N. Honorio"},{"family":"Killeen","given":"Tim J."},{"family":"Mostacedo","given":"Bonifacio"},{"family":"Vasquez","given":"Rodolfo"},{"family":"Assis","given":"Rafael L."},{"family":"Terborgh","given":"John"},{"family":"Wittmann","given":"Florian"},{"family":"Andrade","given":"Ana"},{"family":"Laurance","given":"William F."},{"family":"Laurance","given":"Susan G. W."},{"family":"Marimon","given":"Beatriz S."},{"family":"Marimon","given":"Ben-Hur"},{"family":"Vieira","given":"Ima Célia Guimarães"},{"family":"Amaral","given":"Iêda Leão"},{"family":"Brienen","given":"Roel"},{"family":"Castellanos","given":"Hernán"},{"family":"López","given":"Dairon Cárdenas"},{"family":"Duivenvoorden","given":"Joost F."},{"family":"Mogollón","given":"Hugo F."},{"family":"Matos","given":"Francisca Dionízia de Almeida"},{"family":"Dávila","given":"Nállarett"},{"family":"García-Villacorta","given":"Roosevelt"},{"family":"Diaz","given":"Pablo Roberto Stevenson"},{"family":"Costa","given":"Flávia"},{"family":"Emilio","given":"Thaise"},{"family":"Levis","given":"Carolina"},{"family":"Schietti","given":"Juliana"},{"family":"Souza","given":"Priscila"},{"family":"Alonso","given":"Alfonso"},{"family":"Dallmeier","given":"Francisco"},{"family":"Montoya","given":"Alvaro Javier Duque"},{"family":"Piedade","given":"Maria Teresa Fernandez"},{"family":"Araujo-Murakami","given":"Alejandro"},{"family":"Arroyo","given":"Luzmila"},{"family":"Gribel","given":"Rogerio"},{"family":"Fine","given":"Paul V. A."},{"family":"Peres","given":"Carlos A."},{"family":"Toledo","given":"Marisol"},{"family":"C","given":"Gerardo A. Aymard"},{"family":"Baker","given":"Tim R."},{"family":"Cerón","given":"Carlos"},{"family":"Engel","given":"Julien"},{"family":"Henkel","given":"Terry W."},{"family":"Maas","given":"Paul"},{"family":"Petronelli","given":"Pascal"},{"family":"Stropp","given":"Juliana"},{"family":"Zartman","given":"Charles Eugene"},{"family":"Daly","given":"Doug"},{"family":"Neill","given":"David"},{"family":"Silveira","given":"Marcos"},{"family":"Paredes","given":"Marcos Ríos"},{"family":"Chave","given":"Jerome"},{"family":"Filho","given":"Diógenes de Andrade Lima"},{"family":"Jørgensen","given":"Peter Møller"},{"family":"Fuentes","given":"Alfredo"},{"family":"Schöngart","given":"Jochen"},{"family":"Valverde","given":"Fernando Cornejo"},{"family":"Fiore","given":"Anthony Di"},{"family":"Jimenez","given":"Eliana M."},{"family":"Mora","given":"Maria Cristina Peñuela"},{"family":"Phillips","given":"Juan Fernando"},{"family":"Rivas","given":"Gonzalo"},{"family":"Andel","given":"Tinde R.","dropping-particle":"van"},{"family":"Hildebrand","given":"Patricio","dropping-particle":"von"},{"family":"Hoffman","given":"Bruce"},{"family":"Zent","given":"Eglée L."},{"family":"Malhi","given":"Yadvinder"},{"family":"Prieto","given":"Adriana"},{"family":"Rudas","given":"Agustín"},{"family":"Ruschell","given":"Ademir R."},{"family":"Silva","given":"Natalino"},{"family":"Vos","given":"Vincent"},{"family":"Zent","given":"Stanford"},{"family":"Oliveira","given":"Alexandre A."},{"family":"Schutz","given":"Angela Cano"},{"family":"Gonzales","given":"Therany"},{"family":"Nascimento","given":"Marcelo Trindade"},{"family":"Ramirez-Angulo","given":"Hirma"},{"family":"Sierra","given":"Rodrigo"},{"family":"Tirado","given":"Milton"},{"family":"Medina","given":"María Natalia Umaña"},{"family":"Heijden","given":"Geertje","dropping-particle":"van der"},{"family":"Vela","given":"César I. A."},{"family":"Torre"