Gretel Geada López

Phylogeny and classification of Pinus

We used chloroplast DNA sequences from matK and rbcL to infer the phylogeny for 101 of the approximately 111 species of Pinus (Pinaceae). At the level of subsection and above, the cpDNA tree is congruent with phylogenies based on nuclear DNA with one notable exception: cpDNA sequences from subsect. Contortae are sister to all other North American hard pines rather than occupying a more derived position in the same clade. We used the cpDNA tree plus evidence from nuclear ribosomal DNA and morphology to propose a new classification for the genus. The molecular phylogenies are symmetrical at the deepest branches of the genus, allowing for the delineation of two subgenera, each with two sections that form sister groups. Within sections, clades were slightly asymmetric and sometimes ambiguously resolved. To accomodate ambiguity in some interrelationships, avoid the creation of new ranks, and retain traditional names, we recognised up to three monophyletic subsections per section. Subgenus Pinus (the diploxylon, or hard pines) is divided into the predominantly Eurasian and Mediterranean section Pinus, composed of subsections Pinus and Pinaster, and the strictly North American section Trifoliae, composed of subsections Australes, Ponderosae, and Contortae. Subgenus Strobus (the haploxylon, or soft pines) is divided into the strictly North American section Parrya, composed of subsections Cembroides, Nelsoniae, and Balfourianae, and the Eurasian and North American section Quinquefoliae, composed of subsections Gerardianae, Krempfianae, and Strobus. Mapping of ten morphological and distributional characters indicates that two were diagnostic for infrageneric taxa: the number of vascular bundles per leaf distinguishes subgenus Pinus from subgenus Strobus, and a terminal-positioned umbo on the ovulate cone scale is diagnostic of subsect. Strobus.

Use of simultaneous analyses to guide fossil-based calibrations of Pinaceae phylogeny

Uncertainties in the age and phylogenetic position of Pinaceae fossils present significant obstacles to our understanding of the timing of diversification in the family. We demonstrate that simultaneous phylogenetic analyses of chloroplast DNA (matK and rbcL) and nonmolecular characters that include both extant genera and a limited number of fossil taxa provide useful hypotheses for calibrating molecular trees. Root placements varied for Pinaceae, with Bayesian analyses recovering mutually monophyletic subfamilies Pinoideae and Abietoideae and parsimony analyses recovering Abietoideae as paraphyletic by placing the root between Cedrus and the remaining genera. The inferred phylogenetic positions of fossil taxa Pityostrobus bernissartensis as the sister group to Pinus and Pseudolarix erensis as the sister group to extant Pseudolarix were used to guide divergence‐time calibrations; these calibrations yielded an Early Cretaceous and an Early Jurassic age for crown‐group Pinaceae, respectively. The older age estimates based on Pseudolarix erensis are supported by weaker evidence from the fossil record but are consistent with recent reports of Early Cretaceous leaf fossils that appear to coincide with extant genera. There remains a great need to characterize the anatomy of extant and fossil species and to code additional nonmolecular characters.

Actions for the Restoration of the Biodiversity of Forest Ecosystems in Cuba

Human will and interests have used landscapes without limits for different purposes, usually for the economic benefit of a minority [1]. Nowadays, the Earth is threatened daily by the degradation of its ecosystems due to fragmentation. One of the main consequences is biodi‐ versity loss. Despite the economic progress and conservation actions carried out in many countries, the planet is losing genuine tropical forest, which is distributed mainly in the “low and middle income countries”. The reasons are diverse: inappropriate use of extractive practices in forestry related to wood and non-wood products, land use change when clearing the forest for agriculture and cattle ranching, tourism development, and others. These reasons have facilitated the introduction of new species that then behave as invasive species [2], which usually produce strong competition with local species, reducing biomass and the forest’s productivity.

Tipos funcionales de plantas según su respuesta a las perturbaciones en un bosque semideciduo micrófilo costero de Cuba Oriental

Como consecuencia de las perturbaciones antropicas producidas en el bosque semideciduo microfilo de la Reserva Ecologica Siboney Jutici se produjeron cambios en la cobertura vegetal de sus ecotopos. Futuras acciones de restauracion de las areas antropizadas exigirian conocer el rol funcional de las especies durante los procesos postperturbacion. En el trabajo se evaluo el nivel de las perturbaciones en diferentes sitios, considerando las fuentes y caracteristicas de estas. Para la determinacion de los tipos funcionales se analizaron la abundancia relativa de las especies en sitios desigualmente perturbados, los rasgos funcionales de estas (demanda de luz o tolerancia a la sombra, tipo de fruto, dispersion de las semillas) y se realizo un analisis de cluster. Se diferenciaron tres tipos funcionales de respuesta a las perturbaciones a los que se les denominaron: cobertoras, colonizadoras y estabilizadoras. Al interior de cada tipo funcional se diferencio un grupo de especies que condicionan la dinamica postperturbacion y propician el avance de la recuperacion (especies dinamogeneticas) mientras que otro grupo (diversificadoras) le confiere diversidad, redundancia y resiliencia al sistema. La redundancia de las especies dentro de los tipos funcionales definidos, aunque con diferencia en la composicion y abundancia de las estas, les permite estar presentes y desempenar su funcion en cualquiera de los niveles de perturbacion, por lo que constituyen una poderosa herramienta para el desarrollo de estrategias de restauracion ecologica en ese bosque