Manuel Costa

Vegetación de Doñana (Huelva, España)

Monografia fitosociologica de la vegetacion de la Reserva Biologica y del Parque Nacional de Donana (Huelva, Espana). En base a la publicacion de 461 inventarios y 25 sininventarios se describen 70 asociaciones pertenecientes a 28 clases de vegetacion, asi como se dan a conocer cinco sinasociaciones. De cada asociacion se aportan datos floristicos, ecologicos, estructurales, corologicos y taxonomicos, y en muchos casos sus relaciones con las asociaciones geovicarias. Ademas de numerosos esquemas catenales y dinamicos de la vegetacion, se incluye una lista de los sintaxones y un catalogo alfabetico de las plantas vasculares de Donana y de las comentadas en el texto.

Cissampeloflavone, a chalcone-flavone dimer from Cissampelos pareira

From the aerial parts of Cissampelos pareira L. (Menispermaceae), a chalcone-flavone dimer has been isolated which, mainly from NMR spectroscopic and MS data, was proved to be 2-(4-hydroxy-3-methoxyphenyl)-7-(4-methoxyphenyl)-6-(2-hydroxy-4,6-dimethoxybenzoyl)-furano[3,2-g]benzopyran-4-one. This has been assigned the trivial name cissampeloflavone. The compound has good activity against Trypanosoma cruzi and T. brucei rhodesiense and has a low toxicity to the human KB cell line.

The organismic and the continuous approaches applied to phytosociological relationships in a lowland neotropical forest, Venezuela

Abstract The Organismic and the Continuous theories are traditionally considered as antagonist in ecology studies. In this research, we make the floristic characterization of different forest communities and establish the corresponding classification, taking into account the approaches derived from the theories aforementioned. We used 1 ha plots to evaluate individuals bigger than 10 cm dbh (diameter at breast height). In each one of that plots, four sub-plots of 100 m2 were measured, to study all the spermatophyta in the understory. The data obtained were considered in an Enlarged Importance Index (EII), for each species in each plot. Then, the phytosociological relationships were established, according to the importance and appearance of all the species in all the plots and the results from conglomerate and multivariate analyses. We found a great unit of vegetation where the species Pentaclethra macroloba and Carapa guianensis are characteristic-dominant. In position of summit and hillside, an Alexa imperatricis Forest was identified. A valley type exists where a Catostemma commune Forest is present, and there is another valley with a Mora excelsa Forest. We found that Organismic and Continuous approaches could be complementary to get a better understanding of the tropical forest ecosystems.

An assessment of the floristic composition, structure and possible origin of a liana forest in the Guayana Shield

Liana is a life form that possesses high importance in many Neotropical forests. Density of climbers apparently increases with the intervention rate (e.g. logging). The aim of this work is to characterize the structure, floristic composition and soils of a sector classified as Liana Forest (LF). We identified an LF sector in a not-logged area; three 1 ha square plots were measured (individuals ≥ 10 cm dbh, “diameter at breast height”). In each plot, we evaluate four 100 m2 square understory subplots (all spermatophyta individuals < 10 cm dbh). LF has a low canopy ( < 15 m) and is dominated by Alexa imperatricis and Pentaclethra macroloba. Basal area (20.4 m2ha− 1) and diversity (H′ = 2.6) are lower than other surrounding plots. Understory is dominated by gnarled climbers, and the most important are Cheiloclinium hippocrateoides and Bauhinia scala-simiae. Soil is extremely acidic, with very low fertility but is similar to neighboring places. We conclude that LF was neither originated by edaphic restrictions nor logging; LF probably suffered a hurricane wind that fell down most of the canopy trees, thick individuals of climber species also disappeared, and the current successional stage favors a recovery dominated with thin individuals of this life form.

Flora Matritensis,1 (Pteridophyta)

La flora pteridologica de la provincia de Madrid y comarcas limitrofes consta de 24 generos, 54 especies, siete subespecies, dos formas y doce hibridos. La obra posee claves para determinar ordenes, generos, especies, subespecies y formas. Para cada taxon se indica el biotipo, tamano, ecologia, fitosociologia, pisos bioclimaticos, corologia general y regional, asi como la ploidia y numero de cromosomas.

The Coastal Levantine Area

The Coastal Levantine area is a very diverse territory situated between the Cap de Creus and the Cap de la Nau. The wide variety of environments and ecological conditions that occur in this area determine its great diversity and richness from the vegetation point of view. Forest composition depends mainly on climatic factors, geomorphology and soil features, and are currently dominated by evergreen sclerophyllous (Quercus ilex, Q. rotundifolia, Q. suber), conifer (Pinus halepensis, P. pinaster, P. pinea, P. salzmannii, P. sylvestris), and deciduous (Fagus sylvatica, Quercus petraea) and semi-deciduous (Quercus faginea, Q. canariensis, Q. pubescens, Q. pyrenaica) species in inland areas with heavier rainfall or humidity. As a result of land use and human disturbances, shrubby vegetation, scrub, grasslands, along with thermophilic natural or reforested pine forests, are the most widespread vegetation formations, especially at lower altitudes. Scrub formations spread on both siliceous and calcareous substrates, particularly those that grow on thermophile calcareous ones are species-rich communities with numerous endemic plants. Coastal vegetation, including dunes, marshes, salt-marshes and cliffs, is well represented, with slight variations in some parameters, like salt concentration, water availability, soil features, etc., responsible for the floristic composition of the communities growing in these environments. As in the rest of the Iberian Peninsula, vegetation, especially forests and coastal areas, is affected by a long-standing tradition of human use and transformations (fires, massive urbanisation, grazing, felling, etc.), and well-structured formations currently have become quite scarce.