Nuevos registros para la flora vascular de Colombia presentes en la Orinoquia y reseña histórica de las expediciones botánicas a la región

18 new records to the vascular flora of Colombia found in the Orinoquia region are recorded: Duguetia riberensis Aristeg. ex Maas & Boon, Trigynaea duckei (R .E. Fr.) R. E. Fr. (Annonaceae); Tassadia medinae (Morillo) Morillo (Apocynaceae); Jaracanda orinocensis Sandw. (Bignoniaceae); Polycarpaea corymbosa (L.) Lam. var. brasiliensis (Cambess.) Chodat & Hassl. (Caryophyllaceae); Murdannia burchellii (C. B. Clarke) M. Pell. y M. aff. triquetra (Wall. ex C. B. Clarke) G.Brückn (Commelinaceae); Enterolobium barinense L. Cárdenas & Rodr.-Carr., Machaerium tovarense Pittier, Muellera crucisrubierae (Pittier) M. Sousa, and Tachigali davidsei Zarucchi & Herend. (Leguminosae); Nectandra bartlettiana Lasser (Lauraceae); Lindernia brachyphylla Pennell ex Steyerm. (Linderniaceae); Campomanesia aromatica (Aubl.) Griseb. (Myrtaceae); Christiana africana DC. (Malvaceae); Dulacia cyanocarpa Sleumer (Olacaceae); Phyllanthus microphyllus Kunth (Phyllanthaceae), and Gouania wurdackii Steyerm. (Rhamnaceae). These species were collected in the states of Arauca and Vichada in Colombia. Aspects related with the taxonomy and nomenclature of these new records, geographical distributions, and affinities with the flora of the Llanos of Venezuela as well as other regions with floristic similarities are discussed, and information about the exploration in the region is documented.Se registran 18 novedades para la flora vascular de Colombia a partir de ejemplares recolectados en la región dela Orinoquia. Los nuevos registros corresponden a: Duguetia riberensis Aristeg. ex Maas & Boon, Trigynaeaduckei (R. E. Fr.) R. E. Fr. (Annonaceae); Tassadia medinae (Morillo) Morillo (Apocynaceae); Jaracandaorinocensis Sandw. (Bignoniaceae); Polycarpaea corymbosa (L.) Lam. var. brasiliensis (Cambess.) Chodat &Hassl. (Caryophyllaceae); Murdannia burchellii (C. B. Clarke) M. Pell. y M. aff. triquetra (Wall. ex C. B. Clarke)G. Brückn (Commelinaceae); Enterolobium barinense L. Cárdenas & Rodr.-Carr., Machaerium tovarense Pittier,Muellera crucisrubierae (Pittier) M. Sousa y Tachigali davidsei Zarucchi & Herend. (Leguminosae), Nectandrabartlettiana Lasser (Lauraceae); Lindernia brachyphylla Pennell ex Steyerm. (Linderniaceae); Campomanesiaaromatica (Aubl.) Griseb. (Myrtaceae); Christiana africana DC. (Malvaceae); Dulacia cyanocarpa Sleumer(Olacaceae); Phyllanthus microphyllus Kunth (Phyllanthaceae) y Gouania wurdackii Steyerm. (Rhamnaceae).Estas especies fueron recolectadas en los departamentos de Arauca y Vichada. Se discuten aspectos relacionadoscon la taxonomía y nomenclatura de estos nuevos registros, su distribución geográfica, sus afinidades con la florapresente en la Orinoquia venezolana y regiones con características florísticas similares. Se agrega una reseñahistórica de las exploraciones en los llanos colombianos

Nuevos registros para la flora vascular de Colombia presentes en la Orinoquia y reseña histórica de las expediciones botánicas a la región

18 new records to the vascular flora of Colombia found in the Orinoquia region are recorded: Duguetia riberensis Aristeg. ex Maas & Boon, Trigynaea duckei (R .E. Fr.) R. E. Fr. (Annonaceae); Tassadia medinae (Morillo) Morillo (Apocynaceae); Jaracanda orinocensis Sandw. (Bignoniaceae); Polycarpaea corymbosa (L.) Lam. var. brasiliensis (Cambess.) Chodat & Hassl. (Caryophyllaceae); Murdannia burchellii (C. B. Clarke) M. Pell. y M. aff. triquetra (Wall. ex C. B. Clarke) G.Brückn (Commelinaceae); Enterolobium barinense L. Cárdenas & Rodr.-Carr., Machaerium tovarense Pittier, Muellera crucisrubierae (Pittier) M. Sousa, and Tachigali davidsei Zarucchi & Herend. (Leguminosae); Nectandra bartlettiana Lasser (Lauraceae); Lindernia brachyphylla Pennell ex Steyerm. (Linderniaceae); Campomanesia aromatica (Aubl.) Griseb. (Myrtaceae); Christiana africana DC. (Malvaceae); Dulacia cyanocarpa Sleumer (Olacaceae); Phyllanthus microphyllus Kunth (Phyllanthaceae), and Gouania wurdackii Steyerm. (Rhamnaceae). These species were collected in the states of Arauca and Vichada in Colombia. Aspects related with the taxonomy and nomenclature of these new records, geographical distributions, and affinities with the flora of the Llanos of Venezuela as well as other regions with floristic similarities are discussed, and information about the exploration in the region is documented.Se registran 18 novedades para la flora vascular de Colombia a partir de ejemplares recolectados en la región dela Orinoquia. Los nuevos registros corresponden a: Duguetia riberensis Aristeg. ex Maas & Boon, Trigynaeaduckei (R. E. Fr.) R. E. Fr. (Annonaceae); Tassadia medinae (Morillo) Morillo (Apocynaceae); Jaracandaorinocensis Sandw. (Bignoniaceae); Polycarpaea corymbosa (L.) Lam. var. brasiliensis (Cambess.) Chodat &Hassl. (Caryophyllaceae); Murdannia burchellii (C. B. Clarke) M. Pell. y M. aff. triquetra (Wall. ex C. B. Clarke)G. Brückn (Commelinaceae); Enterolobium barinense L. Cárdenas & Rodr.-Carr., Machaerium tovarense Pittier,Muellera crucisrubierae (Pittier) M. Sousa y Tachigali davidsei Zarucchi & Herend. (Leguminosae), Nectandrabartlettiana Lasser (Lauraceae); Lindernia brachyphylla Pennell ex Steyerm. (Linderniaceae); Campomanesiaaromatica (Aubl.) Griseb. (Myrtaceae); Christiana africana DC. (Malvaceae); Dulacia cyanocarpa Sleumer(Olacaceae); Phyllanthus microphyllus Kunth (Phyllanthaceae) y Gouania wurdackii Steyerm. (Rhamnaceae).Estas especies fueron recolectadas en los departamentos de Arauca y Vichada. Se discuten aspectos relacionadoscon la taxonomía y nomenclatura de estos nuevos registros, su distribución geográfica, sus afinidades con la florapresente en la Orinoquia venezolana y regiones con características florísticas similares. Se agrega una reseñahistórica de las exploraciones en los llanos colombianos

Rarity of monodominance in hyperdiverse Amazonian forests.

Tropical forests are known for their high diversity. Yet, forest patches do occur in the tropics where a single tree species is dominant. Such "monodominant" forests are known from all of the main tropical regions. For Amazonia, we sampled the occurrence of monodominance in a massive, basin-wide database of forest-inventory plots from the Amazon Tree Diversity Network (ATDN). Utilizing a simple defining metric of at least half of the trees ≥ 10 cm diameter belonging to one species, we found only a few occurrences of monodominance in Amazonia, and the phenomenon was not significantly linked to previously hypothesized life history traits such wood density, seed mass, ectomycorrhizal associations, or Rhizobium nodulation. In our analysis, coppicing (the formation of sprouts at the base of the tree or on roots) was the only trait significantly linked to monodominance. While at specific locales coppicing or ectomycorrhizal associations may confer a considerable advantage to a tree species and lead to its monodominance, very few species have these traits. Mining of the ATDN dataset suggests that monodominance is quite rare in Amazonia, and may be linked primarily to edaphic factors

Phylogenetic diversity of Amazonian tree communities

This is the peer reviewed version of the following article: Honorio Coronado, E. N., Dexter, K. G., Pennington, R. T., Chave, J., Lewis, S. L., Alexiades, M. N., Alvarez, E., Alves de Oliveira, A., Amaral, I. L., Araujo-Murakami, A., Arets, E. J. M. M., Aymard, G. A., Baraloto, C., Bonal, D., Brienen, R., Cerón, C., Cornejo Valverde, F., Di Fiore, A., Farfan-Rios, W., Feldpausch, T. R., Higuchi, N., Huamantupa-Chuquimaco, I., Laurance, S. G., Laurance, W. F., López-Gonzalez, G., Marimon, B. S., Marimon-Junior, B. H., Monteagudo Mendoza, A., Neill, D., Palacios Cuenca, W., Peñuela Mora, M. C., Pitman, N. C. A., Prieto, A., Quesada, C. A., Ramirez Angulo, H., Rudas, A., Ruschel, A. R., Salinas Revilla, N., Salomão, R. P., Segalin de Andrade, A., Silman, M. R., Spironello, W., ter Steege, H., Terborgh, J., Toledo, M., Valenzuela Gamarra, L., Vieira, I. C. G., Vilanova Torre, E., Vos, V., Phillips, O. L. (2015), Phylogenetic diversity of Amazonian tree communities. Diversity and Distributions, 21: 1295–1307. doi: 10.1111/ddi.12357, which has been published in final form at 10.1111/ddi.12357Aim: To examine variation in the phylogenetic diversity (PD) of tree communities across geographical and environmental gradients in Amazonia. Location: Two hundred and eighty-three c. 1 ha forest inventory plots from across Amazonia. Methods: We evaluated PD as the total phylogenetic branch length across species in each plot (PDss), the mean pairwise phylogenetic distance between species (MPD), the mean nearest taxon distance (MNTD) and their equivalents standardized for species richness (ses.PDss, ses.MPD, ses.MNTD). We compared PD of tree communities growing (1) on substrates of varying geological age; and (2) in environments with varying ecophysiological barriers to growth and survival. Results: PDss is strongly positively correlated with species richness (SR), whereas MNTD has a negative correlation. Communities on geologically young- and intermediate-aged substrates (western and central Amazonia respectively) have the highest SR, and therefore the highest PDss and the lowest MNTD. We find that the youngest and oldest substrates (the latter on the Brazilian and Guiana Shields) have the highest ses.PDss and ses.MNTD. MPD and ses.MPD are strongly correlated with how evenly taxa are distributed among the three principal angiosperm clades and are both highest in western Amazonia. Meanwhile, seasonally dry tropical forest (SDTF) and forests on white sands have low PD, as evaluated by any metric. Main conclusions: High ses.PDss and ses.MNTD reflect greater lineage diversity in communities. We suggest that high ses.PDss and ses.MNTD in western Amazonia results from its favourable, easy-to-colonize environment, whereas high values in the Brazilian and Guianan Shields may be due to accumulation of lineages over a longer period of time. White-sand forests and SDTF are dominated by close relatives from fewer lineages, perhaps reflecting ecophysiological barriers that are difficult to surmount evolutionarily. Because MPD and ses.MPD do not reflect lineage diversity per se, we suggest that PDss, ses.PDss and ses.MNTD may be the most useful diversity metrics for setting large-scale conservation priorities.FINCyT - PhD studentshipSchool of Geography of the University of LeedsRoyal Botanic Garden EdinburghNatural Environment Research Council (NERC)Gordon and Betty Moore FoundationEuropean Union's Seventh Framework ProgrammeERCCNPq/PELDNSF - Fellowshi

Phylogenetic diversity of Amazonian tree communities

Aim: To examine variation in the phylogenetic diversity (PD) of tree communities across geographical and environmental gradients in Amazonia. Location: Two hundred and eighty-three c. 1 ha forest inventory plots from across Amazonia. Methods: We evaluated PD as the total phylogenetic branch length across species in each plot (PDss), the mean pairwise phylogenetic distance between species (MPD), the mean nearest taxon distance (MNTD) and their equivalents standardized for species richness (ses.PDss, ses.MPD, ses.MNTD). We compared PD of tree communities growing (1) on substrates of varying geological age; and (2) in environments with varying ecophysiological barriers to growth and survival. Results: PDss is strongly positively correlated with species richness (SR), whereas MNTD has a negative correlation. Communities on geologically young- and intermediate-aged substrates (western and central Amazonia respectively) have the highest SR, and therefore the highest PDss and the lowest MNTD. We find that the youngest and oldest substrates (the latter on the Brazilian and Guiana Shields) have the highest ses.PDss and ses.MNTD. MPD and ses.MPD are strongly correlated with how evenly taxa are distributed among the three principal angiosperm clades and are both highest in western Amazonia. Meanwhile, seasonally dry tropical forest (SDTF) and forests on white sands have low PD, as evaluated by any metric. Main conclusions: High ses.PDss and ses.MNTD reflect greater lineage diversity in communities. We suggest that high ses.PDss and ses.MNTD in western Amazonia results from its favourable, easy-to-colonize environment, whereas high values in the Brazilian and Guianan Shields may be due to accumulation of lineages over a longer period of time. White-sand forests and SDTF are dominated by close relatives from fewer lineages, perhaps reflecting ecophysiological barriers that are difficult to surmount evolutionarily. Because MPD and ses.MPD do not reflect lineage diversity per se, we suggest that PDss, ses.PDss and ses.MNTD may be the most useful diversity metrics for setting large-scale conservation priorities

The number of tree species on Earth

One of the most fundamental questions in ecology is how many species inhabit the Earth. However, due to massive logistical and financial challenges and taxonomic difficulties connected to the species concept definition, the global numbers of species, including those of important and well-studied life forms such as trees, still remain largely unknown. Here, based on global ground sourced data, we estimate the total tree species richness at global, continental, and biome levels. Our results indicate that there are ∼73,000 tree species globally, among which ∼9,000 tree species are yet to be discovered. Roughly 40% of undiscovered tree species are in South America. Moreover, almost one-third of all tree species to be discovered may be rare, with very low populations and limited spatial distribution (likely in remote tropical lowlands and mountains). These findings highlight the vulnerability of global forest biodiversity to anthropogenic changes in land use and climate, which disproportionately threaten rare species and thus, global tree richness. Please note an (erratum/corrigendum) for this article is available via https://www.pnas.org/doi/10.1073/pnas.220278411

Evolutionary Heritage Influences Amazon Tree Ecology

Lineages tend to retain ecological characteristics of their ancestors through time. However, for some traits, selection during evolutionary history may have also played a role in determining trait values. To address the relative importance of these processes requires large-scale quantification of traits and evolutionary relationships among species. The Amazonian tree flora comprises a high diversity of angiosperm lineages and species with widely differing life-history characteristics, providing an excellent system to investigate the combined influences of evolutionary heritage and selection in determining trait variation. We used trait data related to the major axes of life-history variation among tropical trees (e.g. growth and mortality rates) from 577 inventory plots in closed-canopy forest, mapped onto a phylogenetic hypothesis spanning more than 300 genera including all major angiosperm clades to test for evolutionary constraints on traits. We found significant phylogenetic signal (PS) for all traits, consistent with evolutionarily related genera having more similar characteristics than expected by chance. Although there is also evidence for repeated evolution of pioneer and shade tolerant life-history strategies within independent lineages, the existence of significant PS allows clearer predictions of the links between evolutionary diversity, ecosystem function and the response of tropical forests to global change

Evenness mediates the global relationship between forest productivity and richness

1. Biodiversity is an important component of natural ecosystems, with higher species richness often correlating with an increase in ecosystem productivity. Yet, this relationship varies substantially across environments, typically becoming less pronounced at high levels of species richness. However, species richness alone cannot reflect all important properties of a community, including community evenness, which may mediate the relationship between biodiversity and productivity. If the evenness of a community correlates negatively with richness across forests globally, then a greater number of species may not always increase overall diversity and productivity of the system. Theoretical work and local empirical studies have shown that the effect of evenness on ecosystem functioning may be especially strong at high richness levels, yet the consistency of this remains untested at a global scale. 2. Here, we used a dataset of forests from across the globe, which includes composition, biomass accumulation and net primary productivity, to explore whether productivity correlates with community evenness and richness in a way that evenness appears to buffer the effect of richness. Specifically, we evaluated whether low levels of evenness in speciose communities correlate with the attenuation of the richness–productivity relationship. 3. We found that tree species richness and evenness are negatively correlated across forests globally, with highly speciose forests typically comprising a few dominant and many rare species. Furthermore, we found that the correlation between diversity and productivity changes with evenness: at low richness, uneven communities are more productive, while at high richness, even communities are more productive. 4. Synthesis. Collectively, these results demonstrate that evenness is an integral component of the relationship between biodiversity and productivity, and that the attenuating effect of richness on forest productivity might be partly explained by low evenness in speciose communities. Productivity generally increases with species richness, until reduced evenness limits the overall increases in community diversity. Our research suggests that evenness is a fundamental component of biodiversity– ecosystem function relationships, and is of critical importance for guiding conservation and sustainable ecosystem management decisions