Representatividad a escala regional de un inventario florístico detallado de una hectárea en los andes tropicales

Floristic composition of vascular plants and their distribution is reported for growth habits in a low montane rain forest (2600 m and 2500 mm/yr mean annual precipitation) in the northern Andes, based on a plot of 1 ha. The samples collected represented 318 species/morphospecies, 82 families (nine of which were pteridophytes) and 173 genera. 78% of the samples were identified to species. Groups with most species are pteridophytes (sensu lato), Orchidaceae, Asteraceae, Rubiaceae, Melastomataceae and Piperaceae, that represented 44% of all species recorded. The most diverse genera arePeperomia, Elaphoglossum, Mikania, Anthurium, and Miconia. Three species endemic to Antioquia (Brunellia trianae, Meriania antioquiensis and Mikania fragrans) were found. The individuals found in the plot represent 47% of the species, 48% of the genera and 60% of the families found in Arví Park, a reserve of 11400 hectares in which the plot was located. The plot had 108 species, 30 genera and one family not previously reported for Arvi Park. The number of common taxa between the plot and the Arví Park was 144 species, 142 genera and 69 families. Species richness/family in the plot accounts for 89% of the variation of species richness/family in the Arví Park, and 75% of the generic richness. We conclude that detailed floristic inventory of known area plots provide information representative of the regional flora and permit a rapid approximation of its biodiversity.Se reporta la composición florística de plantas vasculares y su distribución por hábitos de crecimiento en un bosque húmedo montano bajo en el norte de los Andes, con base en una parcela de 1 ha. Dentro de la parcela de 1 ha se colectaron muestras botánicas de manera intensiva y se identificaron 318 especies/morfoespecies, 82 familias (9 de las cuales pertenecen a la división Pteridophyta) y 173 géneros. Orchidaceae, Asteraceae, Rubiaceae, Melastomataceae y Piperaceae aportan el 44% del total de especies registradas en la parcela. Los géneros más diversos sonPeperomia, Elaphoglossum, Mikania, Anthurium y Miconia. Se encontraron tres especies endémicas del departamento de Antioquia (Brunellia trianae, Meriania antioquiensis y Mikania fragrans). Las especies encontradas representan el 47%, los géneros el 48% y las familias el 60% del total con respecto al Parque Arví, una reserva de 11 400 ha donde se localizó la parcela. Se encontraron 108 especies, 30 géneros y 1 familia no reportados previamente para el Parque Arví. El número de taxones comunes entre la parcela y el Parque fue de 144 especies, 142 géneros y 69 familias. La riqueza de especies/familia en la parcela explica el 89% de la variación en la riqueza de especies/familia en al Parque Arví, y la riqueza de géneros el 75%. Se concluye que los inventarios florísticos detallados en parcelas de área conocida aportan información representativa de la flora a nivel regional y permiten una aproximación rápida a su biodiversidad

Regional and large-scale patterns in Amazon forest structure and function are mediated by variations in soil physical and chemical properties

Forest structure and dynamics have been noted to vary across the Amazon Basin in an east-west gradient in a pattern which coincides with variations in soil fertility and geology. This has resulted in the hypothesis that soil fertility may play an important role in explaining Basin-wide variations in forest biomass, growth and stem turnover rates. To test this hypothesis and assess the importance of edaphic properties in affect forest structure and dynamics, soil and plant samples were collected in a total of 59 different forest plots across the Amazon Basin. Samples were analysed for exchangeable cations, C, N, pH with various Pfractions also determined. Physical properties were also examined and an index of soil physical quality developed. Overall, forest structure and dynamics were found to be strongly and quantitatively related to edaphic conditions. Tree turnover rates emerged to be mostly influenced by soil physical properties whereas forest growth rates were mainly related to a measure of available soil phosphorus, although also dependent on rainfall amount and distribution. On the other hand, large scale variations in forest biomass could not be explained by any of the edaphic properties measured, nor by variation in climate. A new hypothesis of self-maintaining forest dynamic feedback mechanisms initiated by edaphic conditions is proposed. It is further suggested that this is a major factor determining forest disturbance levels, species composition and forest productivity on a Basin wide scale

Variation in stem mortality rates determines patterns of above-ground biomass in Amazonian forests: implications for dynamic global vegetation models

Understanding the processes that determine above-ground biomass (AGB) in Amazonian forests is important for predicting the sensitivity of these ecosystems to environmental change and for designing and evaluating dynamic global vegetation models (DGVMs). AGB is determined by inputs from woody productivity [woody net primary productivity (NPP)] and the rate at which carbon is lost through tree mortality. Here, we test whether two direct metrics of tree mortality (the absolute rate of woody biomass loss and the rate of stem mortality) and/or woody NPP, control variation in AGB among 167 plots in intact forest across Amazonia. We then compare these relationships and the observed variation in AGB and woody NPP with the predictions of four DGVMs. The observations show that stem mortality rates, rather than absolute rates of woody biomass loss, are the most important predictor of AGB, which is consistent with the importance of stand size structure for determining spatial variation in AGB. The relationship between stem mortality rates and AGB varies among different regions of Amazonia, indicating that variation in wood density and height/diameter relationships also influences AGB. In contrast to previous findings, we find that woody NPP is not correlated with stem mortality rates and is weakly positively correlated with AGB. Across the four models, basin-wide average AGB is similar to the mean of the observations. However, the models consistently overestimate woody NPP and poorly represent the spatial patterns of both AGB and woody NPP estimated using plot data. In marked contrast to the observations, DGVMs typically show strong positive relationships between woody NPP and AGB. Resolving these differences will require incorporating forest size structure, mechanistic models of stem mortality and variation in functional composition in DGVMs

Variation in wood density across South American tropical forests

Wood density is a critical control on tree biomass, so poor understanding of its spatial variation can lead to large and systematic errors in forest biomass estimates and carbon maps. The need to understand how and why wood density varies is especially critical in tropical America where forests have exceptional species diversity and spatial turnover in composition. As tree identity and forest composition are challenging to estimate remotely, ground surveys are essential to know the wood density of trees, whether measured directly or inferred from their identity. Here, we assemble an extensive dataset of variation in wood density across the most forested and tree-diverse continent, examine how it relates to spatial and environmental variables, and use these relationships to predict spatial variation in wood density over tropical and sub-tropical South America. Our analysis refines previously identified east-west Amazon gradients in wood density, improves them by revealing fine-scale variation, and extends predictions into Andean, dry, and Atlantic forests. The results halve biomass prediction errors compared to a naïve scenario with no knowledge of spatial variation in wood density. Our findings will help improve remote sensing-based estimates of aboveground biomass carbon stocks across tropical South America

Variation in stem mortality rates determines patterns of above-ground biomass in Amazonian forests: implications for dynamic global vegetation models

Understanding the processes that determine above-ground biomass (AGB) in Amazonian forests is important for predicting the sensitivity of these ecosystems to environmental change and for designing and evaluating dynamic global vegetation models (DGVMs). AGB is determined by inputs from woody productivity [woody net primary productivity (NPP)] and the rate at which carbon is lost through tree mortality. Here, we test whether two direct metrics of tree mortality (the absolute rate of woody biomass loss and the rate of stem mortality) and/or woody NPP, control variation in AGB among 167 plots in intact forest across Amazonia. We then compare these relationships and the observed variation in AGB and woody NPP with the predictions of four DGVMs. The observations show that stem mortality rates, rather than absolute rates of woody biomass loss, are the most important predictor of AGB, which is consistent with the importance of stand size structure for determining spatial variation in AGB. The relationship between stem mortality rates and AGB varies among different regions of Amazonia, indicating that variation in wood density and height/diameter relationships also influences AGB. In contrast to previous findings, we find that woody NPP is not correlated with stem mortality rates and is weakly positively correlated with AGB. Across the four models, basin-wide average AGB is similar to the mean of the observations. However, the models consistently overestimate woody NPP and poorly represent the spatial patterns of both AGB and woody NPP estimated using plot data. In marked contrast to the observations, DGVMs typically show strong positive relationships between woody NPP and AGB. Resolving these differences will require incorporating forest size structure, mechanistic models of stem mortality and variation in functional composition in DGVMs

Effect of climate on traits of dominant and rare tree species in the world’s forests

Species’ traits and environmental conditions determine the abundance of tree species across the globe. The extent to which traits of dominant and rare tree species differ remains untested across a broad environmental range, limiting our understanding of how species traits and the environment shape forest functional composition. We use a global dataset of tree composition of >22,000 forest plots and 11 traits of 1663 tree species to ask how locally dominant and rare species differ in their trait values, and how these differences are driven by climatic gradients in temperature and water availability in forest biomes across the globe. We find three consistent trait differences between locally dominant and rare species across all biomes; dominant species are taller, have softer wood and higher loading on the multivariate stem strategy axis (related to narrow tracheids and thick bark). The difference between traits of dominant and rare species is more strongly driven by temperature compared to water availability, as temperature might affect a larger number of traits. Therefore, climate change driven global temperature rise may have a strong effect on trait differences between dominant and rare tree species and may lead to changes in species abundances and therefore strong community reassembly

Large range sizes link fast life histories with high species richness across wet tropical tree floras

Additional co-authors: Luzmila Arroyo, Peter Ashton, Suspense A. Averti Ifo, Gerardo A. C. Aymard, Michel Baisie, William Balee, Michael Balinga, Lindsay F. Banin, Olaf Banki, Christopher Baraloto, Jorcely Barroso, Jean-Francois Bastin, Hans Beeckman, Serge Begne, Natacha Nssi Bengone, Nicholas Berry, Wemo Betian, Vincent Bezard, Lilian Blanc, Pascal Boeckx, Damien Bonal, Frans Bongers, Francis Q. Brearley, Roel Brienen, Foster Brown, Musalmah Bt. Nasaradin, Benoit Burban, David F. R. P. Burslem, Plinio Camargo, Jose Luis Camargo, Wendeson Castro, Carlos Ceron, Victor Chama Moscoso, Colin Chapman, Jerome Chave, Eric Chezeaux, Murray Collins, James Comiskey, David Coomes, Fernando Cornejo Valverde, Flavia R. C. Costa, Aida Cuni-Sanchez, Lola da Costa, Douglas C. Daly, Martin Dančák, Armandu Daniels, Greta Dargie, Stuart Davies, Charles De Canniere, Thales de Haulleville, Jhon del Aguila Pasquel, Geraldine Derroire, Kyle G. Dexter, Anthony Di Fiore, Marie-Noel K. Djuikouo, Jean-Louis Doucet, Vincent Droissart, Gerald Eilu, Thaise Emillio, Julien Engel, Bocko Yannick Enock, Fidele Evouna Ondo, Corneille Ewango, Sophie Fauset, Ted R. Feldpausch, Muhammad Fitriadi, Gerardo Flores Llampazo, Ernest G. Foli, Gabriella Fredriksson, David R.Galbraith, Martin Gilpin, Emanuel Gloor, Christelle Gonmadje, Rene Guillen Villaroel, Jefferson Hall, Keith C. Hamer, Alan Hamilton, Olivier Hardy, Terese Hart, Radim Hédl, Rafael Herrera, Niro Higuchi, Claude Marcel Hladik, Eurídice Honorio Coronado, Isau Huamantupa-Chuquimaco, Walter Huaraca Huasco, Wannes Hubau, Muhammad Idhamsyah, Sascha A. Ismail, Eliana Jimenez, Tommaso Jucker, Elizabeth Kearsley, Lip Khoon Kho, Timothy Killeen, Kanehiro Kitayama, William Laurance, Susan Laurance, Miguel Leal, Simon L. Lewis, Stanislav Lhota, Jeremy Lindsell, Gabriela Lopez-Gonzalez, Jon Lovett, Richard Lowe, William E. Magnusson, Jean-Remy Makana, Yadvinder Malhi, Beatriz Marimon, Ben Hur Marimon Junior, Andrew Marshall, Colin Maycock, Faustin Mbayu, Casimiro Mendoza, Irina Mendoza Polo, Faizah Metali, Vianet Mihindou, Abel Monteagudo-Mendoza, Sam Moore, Patrick Mucunguzi, Jacques Mukinzi, Pantaleo Munishi, Laszlo Nagy, Petrus Naisso, David Neill, Adriano Nogueira Lima, Percy Nunez Vargas, Lucas Ojo, Walter Palacios, Nadir Pallqui Camacho, Alexander Parada Gutierrez, Julie Peacock, Kelvin S.-H. Peh, Antonio Pena Cruz, Colin Pendry, Toby Pennington, Maria Cristina Penuela-Mora, Pascal Petronelli, Oliver L. Phillips, Georgia Pickavance, G. John Pipoly, Nigel Pitman, Axel Dalberg Poulsen, Ghillean T. Prance, Adriana Prieto, Richard B. Primack, Lan Qie, Simon A. Queenborough, Terry Sunderland, Carlos Quesada, Freddy Ramirez Arevalo, Hirma Ramirez-Angulo, Jan Reitsma, Maxime Réjou-Méchain, Anand Roopsind, Francesco Rovero, Ervan Rutishauser, Kamariah Abu Salim, Rafael Salomao, Ismayadi Samsoedin, Muhd Shahruney Saparudin, Juliana Schietti, Ricardo A. Segovia, Julio Serrano, Rafizah Serudia, Douglas Sheil, Natalino Silva, Javier Silva Espejo, Marcos Silveira, Murielle Simo-Droissart, James Singh, Bonaventure Sonké, Thaise Emilio Lopes De Sousa, Juliana Stropp, Rahayu Sukri, Terry Sunderland, Martin Svátek, Michael Swaine, Hermann Taedoumg, Joey Talbot, Sylvester Tan, James Taplin, David Taylor, Hans ter Steege, John Terborgh, Armando Torres-Lezama, John Tshibamba Mukendi, Darlington Tuagben, Peter van de Meer, Geertje van der Heijden, Peter van der Hout, Mark van Nieuwstadt, Bert van Ulft, Rodolfo Vasquez Martinez, Ronald Vernimmen, Barbara Vinceti, Simone Vieira, Ima Celia Guimaries Vieira, Emilio Vilanova Torre, Jason Vleminckx, Lee White, SimonWillcock, Mathew Williams, John T. Woods, Tze Leong Yao, Ishak Yassir, Roderick Zagt& Lise Zemagh

The pace of life for forest trees

Tree growth and longevity trade-offs fundamentally shape the terrestrial carbon balance. Yet, we lack a unified understanding of how such trade-offs vary across the world\u27s forests. By mapping life history traits for a wide range of species across the Americas, we reveal considerable variation in life expectancies from 10 centimeters in diameter (ranging from 1.3 to 3195 years) and show that the pace of life for trees can be accurately classified into four demographic functional types. We found emergent patterns in the strength of trade-offs between growth and longevity across a temperature gradient. Furthermore, we show that the diversity of life history traits varies predictably across forest biomes, giving rise to a positive relationship between trait diversity and productivity. Our pan-latitudinal assessment provides new insights into the demographic mechanisms that govern the carbon turnover rate across forest biomes

Dominance and rarity in tree communities across the globe: Patterns, predictors and threats

Aim: Ecological and anthropogenic factors shift the abundances of dominant and rare tree species within local forest communities, thus affecting species composition and ecosystem functioning. To inform forest and conservation management it is important to understand the drivers of dominance and rarity in local tree communities. We answer the following research questions: (1) What are the patterns of dominance and rarity in tree communities? (2) Which ecological and anthropogenic factors predict these patterns? And (3) what is the extinction risk of locally dominant and rare tree species? Location: Global. Time period: 1990–2017. Major taxa studied: Trees.MethodsWe used 1.2 million forest plots and quantified local tree dominance as the relative plot basal area of the single most dominant species and local rarity as the percentage of species that contribute together to the least 10% of plot basal area. We mapped global community dominance and rarity using machine learning models and evaluated the ecological and anthropogenic predictors with linear models. Extinction risk, for example threatened status, of geographically widespread dominant and rare species was evaluated. Results: Community dominance and rarity show contrasting latitudinal trends, with boreal forests having high levels of dominance and tropical forests having high levels of rarity. Increasing annual precipitation reduces community dominance, probably because precipitation is related to an increase in tree density and richness. Additionally, stand age is positively related to community dominance, due to stem diameter increase of the most dominant species. Surprisingly, we find that locally dominant and rare species, which are geographically widespread in our data, have an equally high rate of elevated extinction due to declining populations through large‐scale land degradation. Main conclusions: By linking patterns and predictors of community dominance and rarity to extinction risk, our results suggest that also widespread species should be considered in large‐scale management and conservation practices

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