Análisis cladístico de la familia Anomodontaceae

The phylogenetic relationships of the species of Anomodon are analyzed along with those of Haplohymenium and Herpetineuron. Anomodon is known only from the northern hemisphere: there are four species in Mexico (several of which extend to Guatemala and/or the Caribbean islands), two in the United States and Canada, on in Europe, and the remaining in south and east Asia. Three species of Haplohymenium, Herpetineuron toccoae, H. acutifolium (Anomodon acutifolius, Granzow- de la Cerda 1989) and Pterogonium gracile are also included. Thirty-one characters for the 17 taxa were analyzed by using the PAUP program, version 3.0, for Macintosh (Swofford 1991). According to the resulting trees, the 11 species of Anomodon are monophyletic as long as it includes the species of Haplohymenium. Anomodon comprises two clads, one equivalent to the subgenus Pseudoanomodon Limpr., including A. longifolius, A. attenuatus, A. giraldii and A. rostratus; the other is equivalent to subgenus Anomodon and includes the species of Haplohymenium. Section Haplohymenium is proposed for the latter genus.Se analizan las relaciones filogenéticas de las especies de Anomodon y sus géneros más afines, Haplohymenium y Herpetineuron. Anomodon está restringido al hemisferio norte: hay cuatro especies en México (algunas de las cuales llegan a Guatemala y/o las islas del Caribe), dos en Estados Unidos y Canadá, una en Europa y el resto en el sur y este asiáticos. Se incluyen tres especies de Haplohymenium, Herpetineuron toccoae, H. acutifolium (=Anomodon acutifolius, Granzow-de la Cerda 1989) y Pterogonium gracile. Los 31 caracteres para los 17 taxa se analizaron con el programa PAUP, versión 3.0, para Macintosh (Swofford 1991). De acuerdo con los árboles resultantes, las 11 especies de Anomodon son monofiléticas, siempre que dicho taxon incluya las especies de Haplohymenium. Anomodon comprende dos clados, uno que coincide con el subgénero Pseudoanomodon constituido por A. longifolius, A. attenuatus, A. giraldii y A. rostratus; el otro coincide con el subgénero Anomodon el cual incluye las especies de Haplohymenium. Se propone la reducción de este último a la categoría de sección Haplohymenium

Multiple Basins Of Attraction In A Tropical Forest: Evidence For Nonequilibrium Community Structure

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/116998/1/ecy2004852575.pd

Successional dynamics in Neotropical forests are as uncertain as they are predictable

Although forest succession has traditionally been approached as a deterministic process, successional trajectories of vegetation change vary widely, even among nearby stands with similar environmental conditions and disturbance histories. Here, we provide the first attempt, to our knowledge, to quantify predictability and uncertainty during succession based on the most extensive long-term datasets ever assembled for Neotropical forests. We develop a novel approach that integrates deterministic and stochastic components into different candidate models describing the dynamical interactions among three widely used and interrelated forest attributes - stem density, basal area, and species density. Within each of the seven study sites, successional trajectories were highly idiosyncratic, even when controlling for prior land use, environment, and initial conditions in these attributes. Plot factors were far more important than stand age in explaining successional trajectories. For each site, the best-fit model was able to capture the complete set of time series in certain attributes only when both the deterministic and stochastic components were set to similar magnitudes. Surprisingly, predictability of stem density, basal area, and species density did not show consistent trends across attributes, study sites, or land use history, and was independent of plot size and time series length. The model developed here represents the best approach, to date, for characterizing autogenic successional dynamics and demonstrates the low predictability of successional trajectories. These high levels of uncertainty suggest that the impacts of allogenic factors on rates of change during tropical forest succession are far more pervasive than previously thought, challenging the way ecologists view and investigate forest regeneration. © 2015, National Academy of Sciences. All rights reserved

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

Estudios cariológicos en cuatro especies de musgos ibéricos

Using the technique of STEERE & al. (1954), Aloina aloides var. ambigua, Anomodon viticulosus, Homalothecium sericeum and Hypnum cupresiforme have been studied karyologically; the chromosome count of each species and some additional comments are presentcd.Siguiendo la técnica de STEERE & al. (1954) se han estudiado cariológicamente Aloina aloides var. ambigua, Anomodon viticulosus, Homalothecium sericeum e Hypnum cupresiforme, aportando además del número cromosomático para cada especie algunos comentarios de interés

Flujo gamético de un musgo acrocárpido dioico: Anomodon viticulosum (Hedw.) Hook. & Tayl., mediante un experimento de trasplante

Se realizaron experimentos de trasplante entre colonias masculinas y femeninas del musgo pleurocárpico dioico Anomodon viticulosus (Hedw.) Hook. & Tayl. en el Prepirineo de Gerona. Con ello se ha pretendido determinar las distancias a que pueden ser transportados, supuestamente por escorrentía, los anterozoides de esta especie. Se dispusieron bloques de 20-30 x 10-15 cm provenientes de colonias con anteridios por encima de colonias con arquegonios exclusivamente y se observó que en éstas últimas se habían desarrollado por primera vez esporófitos al cabo de un año. Al medir las distancias entre dichos esporófitos y los bloques con plantas masculinas situados por encima, se obtuvo que éstas eran de al menos 25 cm