El nombre Salicornietum perennis (sensu lato) e implicaciones nomenclaturales generales

The name Zygophyllo fontanesii-Sarcocornietum perennis is rejected as it is invalid and the new name Halimiono portulacoidis-Salicornietum perennis is proposed with two subassociations: typicum and limonietosum canariensis. The name Salicornietum perennis for Cuban communities is corrected to Salicornietum ambiguaeSe rechaza el nombre Zygophyllo fontanesii-Sarcocornietum perennis por su condición inválida, y se propone el nombre nuevo Halimiono portulacoidis-Salicornietum perennis con dos subasociaciones: typicum y limonietosum canariensis. Se corrige el nombre Salicornietum perennis para las comunidades cubanas a Salicornietum ambiguaeS

Magnetic Nanoparticles of iron oxide as matrices from controlled release

In this paper is carried out preparation of magnetites by different methods, co-precipitation and solvothermal, and its subsequent coating with mesoporous silica. Also, have been characterized using various characterization techniques: XRD, FT-IR, adsorption-desorption of N2 at - 196 ° C, SEM and magnetization curves. The results obtained indicate that the best method is the solvothermal since it allows to obtain uniform nanoparticles, small size with spherical morphology and more magnetism, which makes them suitable to be used as matrice of controlled releaseEn este trabajo se ha llevado a cabo  la preparación de magnetitas  por distintos métodos, coprecipitación y solvotermal,  y su posterior  recubrimiento con sílice mesoporosa. Asimismo, se han caracterizado utilizando diferentes técnicas: DRX, FT-IR, Adsorción-desorción de N2 a -196ºC, curvas de magnetización y SEM. Los resultados obtenidos  indican que es el método solvotermal el que permite obtener nanopartículas homogéneas, de pequeño tamaño, con morfología esférica y mayor magnetismo, propiedades que las hace idóneas para ser utilizadas como matrices de liberación controlad

Temporal and palaeoclimatic context of the evolution of insular woodiness in the Canary Islands

Insular woodiness (IW), referring to the evolutionary transition from herbaceousness toward woodiness on islands, has arisen more than 30 times on the Canary Islands (Atlantic Ocean). One of the IW hypotheses suggests that drought has been a major driver of wood formation, but we do not know in which palaeoclimatic conditions the insular woody lineages originated. Therefore, we provided an updated review on the presence of IW on the Canaries, reviewed the palaeoclimate, and estimated the timing of origin of woodiness of 24 insular woody lineages that represent a large majority of the insular woody species diversity on the Canaries. Our single, broad‐scale dating analysis shows that woodiness in 60%–65% of the insular woody lineages studied originated within the last 3.2 Myr, during which Mediterranean seasonality (yearly summer droughts) became established on the Canaries. Consequently, our results are consistent with palaeoclimatic aridification as a potential driver of woodiness in a considerable proportion of the insular woody Canary Island lineages. However, the observed pattern between insular woodiness and palaeodrought during the last couple of million years could potentially have emerged as a result of the typically young age of the native insular flora, characterized by a high turnover

Insular Woodiness on the Canary Islands: A Remarkable Case of Convergent Evolution

Premise of research. One of the most conspicuous aspects of island floras is the relatively high proportion of woody species. Often, but not always, these woody species have developed wood on the islands and have evolved from herbaceous continental ancestors, a phenomenon known as insular woodiness. Shifts from herbaceousness toward increased woodiness also occur on continents (the broader term “secondary woodiness” is more appropriate here and includes insular woodiness), but comprehensive worldwide knowledge about secondary woodiness within angiosperms remains lacking. We update hypotheses regarding the herbaceous ancestry of woody Canarian lineages in a molecular phylogenetic context and investigate the possible link of secondary woodiness and paedomorphic wood features in the Carlquistian sense. Methodology. We have assembled available literature data from molecular phylogenetic studies, wood anatomical descriptions, floras, and taxonomic revisions to identify the native secondarily woody taxa. Pivotal results. In total, at least 220 native Canary Island species of flowering plants, from 34 genera representing 15 families, are truly insular woody. This represents a significant portion of the native nonmonocot angiosperm species on the Canaries, and all of the insular woody species have paedomorphic wood features in the Carlquistian sense, although this wood anatomical syndrome might be more related to particular life forms. The majority of these insular woody groups typically grow in the markedly dry lowland regions, suggesting a possible link between secondary woodiness and increased drought resistance. Conclusions. The Canary Island flora is characterized by at least 38 independent shifts toward insular woodiness, representing an important portion of the endemic angiosperms on the archipelago. These convergent evolutionary events emphasize the remarkable lability in growth forms between herbaceous and woody lineages, but it remains puzzling which environmental variables trigger these shifts and how these independent shifts are regulated genetically.  NaturalisPlant science

Contribución al estudio fitosociológico del pinar grancanario (Islas Canarias)

Salas, M., Del Arco, M.J. & Pérez de Paz, P.L. Contribución al estudio fitosociológico del pinar grancanario (Islas Canarias). Lazaroa 19:99-117 (1998). Se lleva a cabo una caracterización bioclimática, florística y fitosociológica de Pinetum canariensis, el pinar autóctono de la isla de Gran Canaria, y se describe la nueva subasociación juniperetosum canariensis. Se hacen diversas consideraciones sobre las comunidades arbustivas de sustitución y se describe la nueva asociación Euphorbio regis-jubae-Cistetum monspeliensis

El conejo europeo como ingeniero del paisaje en la alta montaña canaria

Las islas Canarias forman parte de uno de los 25 puntos calientes de biodiversidad del planeta. Los ecosistemas insulares canarios presentan, por lo general, una elevada proporción de especies endémicas terrestres (680 taxones endémicos de plantas vasculares, que representan más del 50% del total de la flora nativa; cf. Reyes-Betancort et al., 2008). Desgraciadamente, los ecosistemas de las islas son muy frágiles y sensibles a cualquier tipo de alteració

Efecto de la inclinación y pedregosidad sobre el reparto del agua de lluvia, su cuantificación y aplicación al estudio de la vegetación en zonas áridas

Para conocer la correcta distribución de la vegeta - ción en un territorio, es fundamental manejar información precisa sobre las variables que la condicionan. Muy probable - mente, el parámetro que condiciona en mayor medida el tipo de vegetación que puede crecer en un lugar es la cantidad de agua de que disponen las plantas. En este sentido, y dejando a un lado las formaciones ligadas a cursos de agua, lagos, etc., el principal origen de este recurso es la lluvia. De esta manera, el estudio de la distribución de la vegetación en cualquier territorio está muy relacionado con el análisis de las precipitaciones que recibe. Para conocer la cantidad de agua de lluvia que recibe una zona se recurre siempre a los datos aportados por las estaciones meteorológicas situadas en la misma. Los datos recogidos por estas estaciones se aplican a una superficie hipotética, homogénea y plana. Esta infor - mación es suficientemente precisa cuando la escala a la que se trabaja es pequeña (1:100.000; 1:50.000), pero cuando se precisa de un mayor detalle, sobre todo en territorios áridos, donde la estructura de la vegetación es abierta y el suelo recibe directamente gran parte de la precipitación, existen condiciones del terreno que condicionan el reparto del agua de lluvia y por tanto el acceso de las plantas a este recurso. Dos de estas variables, quizá las más importantes son la inclinación y la presencia de afloramientos rocosos o de pedregosidad en el suelo. En definitiva, nuestro trabajo consiste en proponer diferentes modelos matemáticos que posibiliten conocer la cantidad real de agua de que disponen las plantas, que denominamos A . Este valor se obtiene a partir de los datos pluviométricos ( P ), relacionándolos con la inclinación del terreno y el porcentaje del mismo ocupado por rocas ( af ). La relación entre la precipitación y la inclinación nos proporciona un valor que denominamos precipitación real ( P ́ ), que es menor cuanto mayor es la inclinación, ya que la cantidad de agua caída debe repartirse en una superficie mayor. La cantidad de afloramiento rocoso aumenta la escorrentía, acumulando agua en las zonas terrosas situadas entre las rocas, por lo que un mayor porcentaje de pedre - gosidad en el suelo conlleva una acumulación de agua en el suelo que lo rodea. De esta manera se proporciona un modelo que permite tanto explicar mejor la distribución de la vegetación en zonas áridas y a escalas grandes (1:25.000 o mayores). Para contrastar el modelo y comprobar su utilidad, se ha realizado un estudio del mismo en diferentes localidades situadas en territorios áridos de la isla de Gran Canaria, una de las Islas Canarias. En esta isla se escogieron 14 lo - calidades situadas en ambientes áridos, con precipitaciones siempre inferiores a 200 mm/m 2 . Entre estas localidades, de condiciones climáticas similares, existe una diversidad vegetal muy importante. La mayor parte están ocupadas por un matorral crasicaule muy abierto dominado por Euphorbia balsamifera , denominado tabaibal de tabaiba dulce, propio de las zonas más desérticas del Archipiélago Canario, y considerado la vegetación potencial de sus zonas áridas e hiperáridas..

Effect of slope and stoniness on the distribution of rainwater, its quantification and application to the study of vegetation in arid zones

For the correct distribution of vegetation in an area, it is essential to manage accurate information on the variables that condition information. Most likely, the parameter that determines further the type of vegetation that can grow in one place is the amount of water available to plants. In this sense, and leaving aside the formations linked to watercourses, lakes, etc., the main source of this resource is the rain. Thus, the study of the distribution of vegetation in any territory is closely related to the analysis of rainfall it receives. To know the amount of rainwater that receives a zone always uses data provided by meteorological stations located in the same. The data collected by these stations are applied to a hypothetical, uniform and flat surface. This information is accurate enough when the scale at which it works is small (1: 100,000, 1: 50,000), but when it requires greater detail, especially in arid areas where the vegetation structure is open and the soil directly receives much of the rainfall, soil conditions exist that determine the distribution of rainwater and therefore access to this resource plants. Two of these variables, perhaps the most important are the inclination and the presence of rocky outcrops or stoniness on the floor. In short, our job is to propose different mathematical models that allow to know the actual amount of water available to plants, we call A. This value is obtained from rainfall data (P), relating to the sloping terrain and the percentage of it occupied by rocks (af). The relationship  between precipitation and tilt gives us a value we call the real precipitation (P'), which is lower the greater the inclination, since the amount of rainfall should be distributed over a larger area. The amount of rocky outcrop increases runoff, accumulating water in the earthy areas between the rocks, so a higher percentage of stoniness in soil involves an accumulation of water in the surrounding soil. Thus a model that allows both better explain the distribution of vegetation in arid areas and on large scales (: 25.000 or higher 1) is provided. To test the model and test its usefulness, it has made a study of it in different localities in arid areas of the island of Gran Canaria, one of the Canary Islands. On this island 14 towns located in arid environments, with precipitation always less than 200 mm/m2 were chosen. Among these locations, with similar climatic conditions, there is a very important plant diversity. Most are occupied by a crasicaule very open scrub dominated by Euphorbia balsamífera, called tabaibal de tabaiba dulce, typical of the most barren areas of the Canary Islands, and considered the potential of its arid and hyper-arid vegetation areas. But other situations are occupied by a lush vegetation: the cardonal, almost totally enclosed high scrub, dominated by Euphorbia canariensis, the cardón; and even formations characterized by the presence of a undertree thicket where different woody species such as Olea cerasiformis, wild olive, Juniperus turbinata subsp. canariensis, the sabina, and even the Canary Island pine, Pinus canariensis. These same plant formations appear as potential in areas with higher rainfall, so its presence in these arid areas should be related to some variable affecting the distribution of water resources. For each of these locations was made calculating the amount of water available to plants, obtaining results that meet the alleged contradiction to find different types of vegetation, with different water requirements in the same climatic zone. Thus it is improving the proposed model provides when it comes to study how vegetation is distributed in arid and territories detail scale is checked. It is clear that as we decrease the scale of the study of the distribution of vegetation in any territory, it is essential to increase the parameters analyzed, especially if it comes to analyzing the situation of vegetation in arid, where the structure of vegetation and seasonality of rainfall make the characteristics of the substrate affect significantly to the presence of vegetation way. Given the scarcity of water resources in these ecosystems, any aspect influencing the availability of water for plants will be of great importance for understanding distribution