Hifomicetos acuáticos de Sierra Nevada y Sierra de los Filabres

N: Cincuenta y dos tacones de los denominados "hifomicteos acuáticos" (49 hifomicetos y anamorfos de asco- y basidiomicetos, y 3 zigomicetos) fueron detectados en muestras de espuma procedentes de ríos y arroyos de Sierra Nevada. Se comenta la presencia de algunas especies y la aparición de varias formas desconocidas."Acuatic Hyphomycetes" from Sierra Nevada and Sierra de los Filabres (South Spain).Conidia of fifty-two taxa of "aquatic Hyphomycetes" (49 aquatic Hyphomycetes and anamorphs of Asco- and Basidiomycetes, and 3 Zygomycetes) were found in foam samples from rivers and streams of Sierra Nevada and Sierra de los Filabres (S-Spain). The results are discussed and some unnamed forms are listed and drawn

Hifomicetos acuáticos de Sierra Nevada y Sierra de los Filabres

"Acuatic Hyphomycetes" from Sierra Nevada and Sierra de los Filabres (South Spain). Conidia of fifty-two taxa of "aquatic Hyphomycetes" (49 aquatic Hyphomycetesand anamorphsof Asco-and Basidiomycetes, and 3 Zygomycetes) were found in foam samples from rivers and streams of Sierra Nevada and Sierra de los Filabres (S-Spain). The results are discussed and some unnamed forms are listed and drawn.Cincuenta y dos tacones de los denominados "hifom icteos acuáticos" (49 hifom icetos y anamorfos de asco- y basidiomicetos, y 3 zigomicetos) fueron detectados en muestras de espuma procedentes de ríos y arroyos de Sierra Nevada. Se comenta la presencia de algunas especies y la aparición de varias formas desconocidas

Phytophthora polonica, a new species isolated from declining Alnus glutinosa stands in Poland

In a survey of Phytophthora associated with alder decline in Poland, several isolates of a homothallic Phytophthora spet al, which could not be assigned to other taxa including Phytophthora alni subspecies, were consistently recovered from rhizosphere soil samples. Their morphology and pathogenicity, as well as sequence data for three nuclear regions (internal transcribed spacer rDNA, elongation factor-1α and β-tubulin) and a coding mitochondrial DNA region (nadh1), were examined. The new Phytophthora species is characterized by the moderate to slow growth rate of its colony in carrot agar at 20°C, high optimal (c. 30°C) and maximum (c. 38°C) growth temperatures, formation of catenulate, often lateral, hyphal swellings, large chlamydospores in agar media and in soil extract, persistent, ovoid to ellipsoid nonpapillate sporangia and large oogonia with paragynous and sometimes amphigynous antheridia. Phytophthora polonica was slightly pathogenic to alder twigs and not pathogenic to trunks of several tree species. In a phylogenetic analysis using either Bayesian inference or maximum likelihood methods, P. polonica falls in clade 8 ‘sensu Kroon (2004)' of Phytophthor

Diversity of patterns and processes in rivers of eastern Andalusia

We document the outstanding diversity of fluvial ecosystems in eastern Andalusia, mostly attributable to the high environmental heterogeneity of the region. The area's altitudinal and climatic gradients are among the most pronounced in the Iberian Peninsula, and together with a concomitant high variability in geological characteristics and human impacts, result in a noticeable heterogeneity of the rivers' thermal regime, discharge regime and chemical properties. Fluvial communities respond to this spatial heterogeneity with marked qualitative and quantitative changes among rivers and along the upstream-downstream continuum, generally exhibiting a great decrease in taxonomic and functional diversity as human impacts increase towards the lower reaches. Discharge fluctuations add heterogeneity on the temporal scale and are an additional essential determinant of biological diversity. Climatic, geological and hydrological characteristics profoundly affect the structure of the riparian vegetation, which in turn strongly conditions the community structure of benthic macroinvertebrates and organic matter turnover in fluvial ecosystems.Se ilustra la notable diversidad de ecosistemas fluviales de Andalucía Oriental, atribuible a la gran heterogeneidad ambiental de esta región. Gradientes altitudinales y climáticos de los más pronunciados de la península Ibérica, concomitantes con una gran variedad de condiciones litológicas y de impactos humanos, acentúan en esta región la heterogeneidad térmica, de caudal y calidad química de los ríos. Las comunidades fluviales responden a esta heterogeneidad espacial con profundos cambios cualitativos y cuantitativos, y generalmente con una disminución de la diversidad taxonómica y funcional en respuesta al incremento de impactos humanos hacia los tramos bajos de los ríos. Las fluctuaciones de caudal suman heterogeneidad en la dimensión tiempo, y constituyen un determinante esencial de los patrones de diversidad biológica. La estructura de la vegetación de ribera responde con grandes cambios a las condiciones climáticas, litológicas e hidrológicas, y ésta a su vez condiciona sustancialmente el marco trófico del ecosistema fluvial

El consumidor virtual y su comportamiento: características, variables influyentes y modelización del proceso de compra

El crecimiento de los establecimientos comerciales minoristas y la implantación de las Nuevas Tecnologías de la Información y Comunicación y, en concreto de Internet, han provocado un importante aumento de las opciones de compra disponibles y, en consecuencia, de los hábitos de compra de los individuos. Las características sociodemográficas, cognitivas y motivacionales del consumidor virtual son algunos de los factores que afectan directamente en su proceso de compra. Por tanto, en el presente trabajo se analizan las principales variables que influyen en el comportamiento de compra del consumidor en entornos virtuales, así como los principales modelos de medición que analizan de manera globalizada las relaciones de influencia entre dichas variables.The relevant retailers increase and the establishment of Information and Communication New Technologies, such as the Internet, have caused that shopping options available for consumer also are being amplified. In consequence, consumers’ shopping habits are changing quickly. Sociodemographic, cognitive and motivational online consumer’s characteristics affect to purchase behavior. So, this work analyzes more influential variables on online environments. Moreover, according literature, it is studied major online consumer behavior models

Intraspecific and within-isolate sequence variation in the ITS rRNA gene region of Pythium mercuriale sp. nov. (Pythiaceae)

Sixteen Pythium isolates from diverse hosts and locations, which showed similarities in their morphology and sequences of the internal transcribed spacer (ITS) region of their rRNA gene, were investigated. As opposed to the generally accepted view, within single isolates ITS sequence variations were consistently found mostly as part of a tract of identical bases (A-T) within ITS1, and of GT or GTTT repeats within the ITS2 sequence. Thirty-one different ITS sequences obtained from 39 cloned ITS products from the 16 isolates showed high sequence and length polymorphisms within and between isolates. However, in a phylogenetic analysis, they formed a cluster distinct from those of other Pythium species. Additional sequencing of two nuclear genes (elongation factor 1α and β-tubulin) and one mitochondrial gene (nadh1) revealed high levels of heterozygosity as well as polymorphism within and between isolates, with some isolates possessing two or more alleles for each of the nuclear genes. In contrast to the observed variation in the ITS and other gene areas, all isolates were phenotypically similar. Pythium mercuriale sp. nov. (Pythiaceae) is characterized by forming thin-walled chlamydospores, subglobose to obovoid, papillate sporangia proliferating internally and smooth-walled oogonia surrounded by multiple antheridia. Maximum likelihood phylogenetic analyses based on both ITS and β-tubulin sequence data place P. mercuriale in a clade between Pythium and Phytophthor

Leaf-litter decomposition in headwater stream: a comparation on the process among four climatic regions

The main purpose of our work was to elucidate factors responsible for the geographical differences in leaf-litter decomposition rates in Spanish oligotrophic headwater streams. Decomposition experiments with alder (Alnus glutinosa) leaf litter were carried out in 22 headwater streams in 4 different climatic regions across the Iberian Peninsula (Cornisa Canta´brica, Cordillera Litoral Catalana, Sierra de Guadarrama, and Sierra Nevada). Streams that were similar in size, flowed mainly over siliceous substrate in catchments with scarce human settlements and activities, and fell within a range of low nutrient concentrations were chosen in each region. Breakdown rates were regionally variable and were low (0.109–0.198% ash-free dry mass [AFDM]/degree day [dd]) in the Cornisa Canta´brica, the most mesic and Atlantic region, and high (0.302–0.639% AFDM/dd) in Sierra de Guadarrama, one of the coldest and most inland areas. Temperature was not the determining factor affecting differences in breakdown rates among regions, and breakdown rates were not related to concentrations of dissolved nutrients. However, microbial reproductive activity (sporulation rates) was significantly correlated with dissolved P concentration. Breakdown rates were explained better by presence and feeding activities of detritivores than by decomposer activity. Incorporation of breakdown rates in assessment schemes of stream ecological status will be difficult because leaf processing does not respond unequivocally to environmental factors when climatic regions are considered. Thus, regional adjustments of baseline standards in reference conditions will be required

Leaf litter decomposition of native and introduced tree species of contrasting quality in headwater streams: How does the regional setting matter?

Terrestrial plant litter is important in sustaining stream food webs in forested headwaters. Leaf litter quality often decreases when native species are replaced by introduced species, and a lower quality of leaf litter inputs may alter litter decomposition at sites afforested with non-native species. However, since detritivore composition and resource use plasticity may depend on the prevalent litter inputs, the extent of the alteration in decomposition can vary between streams. We tested 2 hypotheses using 2 native and 3 introduced species of tree differing in quality in 4 Iberian regions with contrasting vegetational traits: 1) decomposition rates of all plant species would be higher in regions where streams normally receive litter inputs of lower rather than higher quality; 2) a higher resource-use plasticity of detritivores in regions vegetated with plants of lower litter quality will cause a greater evenness in decomposition rates among plant species compared to regions where streams normally receive higher-quality plant litter inputs. Results showed a highly consistent interspecific ranking of decomposition rates across regions driven by litter quality, and a significant regional effect. Hypothesis 1 was supported: decomposition rates of the five litter types were generally higher in streams from regions vegetated with species producing leaf litter of low quality, possibly due to the profusion of caddisfly shredders in their communities. Hypothesis 2 was not supported: the relative differences in decomposition rates among leaf litter species remained essentially unaltered across regions. Our results suggest that, even in regions where detritivores can be comparatively efficient using resources of low quality, caution is needed particularly when afforestation programs introduce plant species of lower litter quality than the native species

Utilidad de catálogos para la confección de monografías

Cualquier labor monográfica o revisión taxonómica puede ser grandemente facilitada por la disponibilidad de catálogos de especies, como el que podría iniciar en un próximo futuro la comunidad de micólogos ibéricos. Pero una catalogación solo es útil si se lleva a cabo con unos criterios y metodología cuidadosamente seleccionados. Se analizan aquí los principales problemas y soluciones adoptadas para la confección de una monografía taxonómica sobre los llamados "hifomicetos acuáticos" (hongos imperfectos) y se extraen conclusiones que se espera sean aplicables a otros tipos de hongos. Se define el grupo ecológico estudiado, y se justifica la necesidad de su revisión. Se detallan las circunstancias que facilitaron su desarrollo, así como las actividades de que consta el proyecto: recopilación bibliográfica, trabajo de campo, trabajo de laboratorio, preparación del herbario, revisión de colecciones de cultivo y herbarios ajenos, redacción e ilustración y modo de publicación.The usefulness of catalogues for the preparation of monographs: Monographs and taxonomic revisions can be significantly assisted by the availability of species catalogues, such as the one which Iberian mycologists may initiate in the near future. But a catalogue is only useful if it is conceived with a carefully selected methodology. This contribution analyzes the problems and solutions adopted for the completion of a taxonomic monograph on the so-called "aquatic hyphomycetes" (Fungi Imperfecti) in the hope that they may be applicable to other groups of fungi. The ecological group under study is defined, and the need for a main revision is justified. The circumstances which enabled it and the activities undertaken are detailed, i.e.: bibliographic revision, field, laboratory and herbarium work, the examination of type material and culture collections, writing up and publication

Diversité des champignons Ingoldiens de quelques rivières du Sud-Ouest de la France

An investigation of aquatic fungal communities from the foam of four South-Western French streams was conducted at the end of autumn. Seventy-six species of Ingoldian fungi have been listed. In addition, ten non-Ingoldian species have been observed. Several unidentified forms are illustrated. Three of these streams were characterised by a great species diversity. Including previous studies on the same four streams, the total number of Ingoldian species is now 89