Phylogenetic classification of the world's tropical forests

Knowledge about the biogeographic affinities of the world’s tropical forests helps to better understand regional differences in forest structure, diversity, composition, and dynamics. Such understanding will enable anticipation of region-specific responses to global environmental change. Modern phylogenies, in combination with broad coverage of species inventory data, now allow for global biogeographic analyses that take species evolutionary distance into account. Here we present a classification of the world’s tropical forests based on their phylogenetic similarity. We identify five principal floristic regions and their floristic relationships: (i) Indo-Pacific, (ii) Subtropical, (iii) African, (iv) American, and (v) Dry forests. Our results do not support the traditional neo- versus paleotropical forest division but instead separate the combined American and African forests from their Indo-Pacific counterparts. We also find indications for the existence of a global dry forest region, with representatives in America, Africa, Madagascar, and India. Additionally, a northern-hemisphere Subtropical forest region was identified with representatives in Asia and America, providing support for a link between Asian and American northern-hemisphere forests.</p

Analog Models of Flanking Structures and a Natural Example in the Quadrilátero Ferrífero, Minas Gerais

ABSTRACT The aim of this study is to present analog models of flanking structures and to analyze the Fábrica Nova synform, Quadrilátero Ferrífero, Minas Gerais, from a geometric point of view. We set up seven models using a linear viscous silicone and produced flanking structures with a shear velocity of 2 cm h-1. At different initial orientations with respect to the shear zone boundary, a rigid cross-cutting element with lubricated boundaries was deformed via sinistral bulk flow at a shear strain of γ = 1.28. The most interesting features of our experiments are the geometries of the different marker lines, which are heterogeneous and resulted from thickening and thinning of the silicone at the cross-cutting element terminations. To compare our analog models and the Fábrica Nova synform, we analyzed the outermost marker line of the analog models and the top surface of the Cauê Formation in the Paleoproterozoic metasediments. The best comparisons between the experiments and the natural example were obtained by our CIS90 model in terms of the flexure shape near the cross-cutting element and the cross-cutting element orientation. Thus, we suggest that the cross-cutting elements in both situations act as obstacles and consequently produce local perturbations in laminar flow

Strong floristic distinctiveness across Neotropical successional forests

Forests that regrow naturally on abandoned fields are important for restoring biodiversity and ecosystem services, but can they also preserve the distinct regional tree floras? Using the floristic composition of 1215 early successional forests (≤20 years) in 75 human-modified landscapes across the Neotropic realm, we identified 14 distinct floristic groups, with a between-group dissimilarity of 0.97. Floristic groups were associated with location, bioregions, soil pH, temperature seasonality, and water availability. Hence, there is large continental-scale variation in the species composition of early successional forests, which is mainly associated with biogeographic and environmental factors but not with human disturbance indicators. This floristic distinctiveness is partially driven by regionally restricted species belonging to widespread genera. Early secondary forests contribute therefore to restoring and conserving the distinctiveness of bioregions across the Neotropical realm, and forest restoration initiatives should use local species to assure that these distinct floras are maintained.Additional co-authors: Alvaro Idárraga, André B. Junqueira, Angelica María Almeyda Zambrano, Ben H. J. de Jong, Bruno Ximenes Pinho, Bryan Finegan, Carolina Castellano-Castro, Daisy Christiane Zambiazi, Daniel Hernán García, Deborah Kennard, Diego Delgado, Eben N. Broadbent, Edgar Ortiz-Malavassi, Eduardo A. Pérez-García, Edwin Lebrija-Trejos, Erika Berenguer, Erika Marín-Spiotta, Esteban Alvarez-Davila, Everardo Valadares de Sá Sampaio, Felipe Melo, Fernando Elias, Filipe França, Florian Oberleitner, Francisco Mora, G. Bruce Williamson, Gabriel Dalla Colletta, George A. L. Cabral, Géraldine Derroire, Geraldo Wilson Fernandes, Hans vanderWal, Heitor Mancini Teixeira, Henricus F. M. Vester, Hernando García, Ima C. G. Vieira, Jaider Jiménez-Montoya, Jarcilene S. deAlmeida-Cortez, Jefferson S. Hall, Jerome Chave, Jess K. Zimmerman, Jhon Edison Nieto, Joice Ferreira, Jorge Rodríguez-Velázquez, Jorge Ruíz, Jos Barlow, José Aguilar-Cano, José Luis Hernández-Stefanoni, Julien Engel, Justin M. Becknell, Kátia Zanini, Madelon Lohbeck, Marcelo Tabarelli, Marco Antonio Romero-Romero, Maria Uriarte, Maria D. M. Veloso, Mário M. Espírito-Santo, Masha T. vander Sande, Michiel van Breugel, Miguel Martínez-Ramos, Naomi B. Schwartz, Natalia Norden, Nathalia Pérez-Cárdenas, Noel González-Valdivia, Pascal Petronelli, Patricia Balvanera, Paulo Massoca, Pedro H. S. Brancalion, Pedro M. Villa, Peter Hietz, Rebecca Ostertag, René López-Camacho, Ricardo G. César, Rita Mesquita, Robin L. Chazdon, Rodrigo Muñoz, Saara J. DeWalt, Sandra C. Müller, Sandra M. Durán, Sebastião Venâncio Martins, Susana Ochoa-Gaona, Susana Rodríguez-Buritica, T. Mitchell Aide, Tony Vizcarra Bentos, Vanessa de S. Moreno, Vanessa Granda, Wayt Thomas, Whendee L. Silver, Yule R. F. Nunes, Lourens Poorte

Dispositivo maciço com extremidade unidimensional para microscopia e espectroscopia óptica de campo próximo

Universidade Federal de Minas GeraisFísicaDepositad

Dispositivo maciço com extremidade unidimensional para microscopia e espectroscopia óptica de campo próximo

Universidade Federal de Minas GeraisFísicaDepositad

Morphogenetic and structural characteristics of andropogon grass submitted to different cutting heights Características morfogênicas e estruturais do capim-andropógon submetido a diferentes alturas de corte

This work was performed aiming to evaluate the morphogenetic and structural characteristics of Andropogon gayanus cv. Planaltina species submitted to three cutting heights (20, 27 and 34 cm). The three cutting heights were allocated in experimental units (12 m²) in a complete randomized block design with three replications. The cuts were done when the light interception by the sward reached 95%. At this moment, the sward height revealed itself constant with values close to 50 cm. The lowest cutting height (20 cm) influenced negatively the final leaf blade length, the number of live leaves, the leaf lifespan, the stem elongation rate and the tiller population density, and it influenced positively the phyllochron and the leaf senescence rate. Probably, cuts at 20 cm height caused a high decapitation and death of the tillers. The worst growth conditions in addition to the blossom of this specie occurred during fall resulted in higher stem elongation rates and number of live leaves, and lower phyllochron, final leaf blade length, and leaf lifespan. The sward height can be used as a practical and efficient criterion in the management of andropogon grass. Under intermittent management conditions, the regrowth of andropogon grass must be interrupted when the sward reaches 50 cm height, and the defoliation must be interrupted when the stubble height is close to 27 cm.<br>Este trabalho foi realizado com o objetivo de avaliar as características morfogênicas e estruturais da espécie Andropogon gayanus cv. Planaltina, submetida a três alturas de corte (20, 27 e 34 cm). As três alturas de corte foram alocadas às unidades experimentais (12 m²) em delineamento de blocos completos casualizados com três repetições. Os cortes foram realizados quando a interceptação luminosa pelo dossel atingiu 95%. A altura do dossel nesse momento mostrou-se constante, com valores próximos a 50 cm. A menor altura de corte (20 cm) influenciou negativamente o comprimento final da lâmina foliar, o número de folhas vivas, a duração de vida da folha, a taxa de alongamento de colmo e a densidade populacional de perfilhos, e positivamente o filocrono e a taxa de senescência de folhas. Provavelmente, cortes a 20 cm de altura causaram elevada decapitação e morte de perfilhos. As piores condições de crescimento junto do florescimento ocorrido durante o outono resultaram em maiores taxas de alongamento de colmos e número de folhas vivas e em menor filocrono, comprimento final da lâmina foliar e duração de vida da folha. A altura do dossel pode ser utilizada como critério prático e eficiente de manejo do capim-andropógon. Em condições de manejo intermitente, a rebrotação deve ser interrompida quando o dossel atingir 50 cm de altura, e a desfolhação, quando a altura de resíduo ficar próxima de 27 cm