DIALNET OAI Articles
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Dialnet (Difusión de Alertas en la Red) es una plataforma de recursos y servicios documentales, cuyo objetivo fundamental se centra en mejorar la visibilidad y el acceso a la literatura científica hispana a través de Internet.
Ciencias biológicas
Mostrando recursos 1 - 20 de 16.940
1.
Cytogeography of Cenchrus ciliaris (Poaceae) in Tunisia - Kharrat-Souissi, Amina; Siljak-Yakovlev, Sonja; Brown, Spencer C.; Chaieb, Mohamed
Belonging to the genus Cenchrus with 16�22 species, Cenchrus ciliaris L. (syn. Pennisetum ciliare (L.) Link, buffelgrass) is a perennial, common in warmer regions of both hemispheres, growing as a C4 grass in a wide range of habitats. In the present study we determined chromosome number and nuclear DNA content (2C DNA) for 28 natural populations collected from northern to southern Tunisia. Three ploidy levels were found: one tetraploid population (2n?=?4x?=?36), three pentaploid (2n?=?5x?=?45), and 24 hexaploid populations (2n?=?6x?=?54). The hexaploid chromosome number has already been reported for Tunisian populations of C. ciliaris but tetraploid and pentaploid (2n?=?45) are new...
2.
Comparative Population Biology of Critically Endangered Dracocephalum austriacum (Lamiaceae) in Two Distant Regions - Dostálek, Tomás; Münzbergová, Zuzana
Our study aims to compare the population dynamics of critically endangered species, Dracocephalum austriacum, in two distant regions (Czech and Slovak Karst) with similar habitat conditions, and to evaluate if conclusions concerning factors affecting population performance in one region could help in understanding species dynamics in the other region. Transition matrix models were used to examine population dynamics of the species. Results show that populations in the Slovak Karst are performing better than populations in the Czech Karst. The transitions contributing most to the population growth rates were those of stasis in the small and large adult plant stage. These...
3.
Rook Spring Seed Dispersal in the Agricultural Landscape � Frugivory, Granivory or Accidental Transport? - Czarnecka, Joanna; Kitowski, Ignacy
Seed dispersal seems to be extremely important in agrocoenoses where suitable habitats (patches) are surrounded by an unfavourable environment (matrix). The role of the rook Corvus frugilegus, an omnivorous bird, in seed dispersal was studied in the agricultural landscape of Eastern Poland. We analyzed 739 pellets produced by regurgitation, which were collected under breeding colonies in April, May and June. Our goal was to i) assess the structure of the seed pool in pellets; ii) evaluate the temporal variation in the pellet seed pool on two different time scales; iii) compare the species composition of seeds in pellets and vegetation...
4.
Germination and Seedling Responses of Subalpine Plants to Different Soil Substrates - Isselin-Nondedeu, Francis; Bédécarrats, Alain
In this study we explored the regeneration niche of 18 alpine plant species by testing the germination responses and seedling growth to soil mixtures made with gypsum, ophiolite, and quartzite, and a control soil. We analyzed different phases of germination: time of radicle emergence, germination duration, and germination percentage, and thereafter seedling performance measured using seedling biomasses. Species were grouped as acidophilous, basophilous and neutrophilous according to their Ellenberg indicator values. Seeds were germinated on each soil mixture in a greenhouse, and then seedlings were selected and transplanted outdoors to grow for one season at 2,050 m a.s.l. The time...
5.
Functional Plant Traits and Species Assemblage in Pyrenean Snowbeds - Ninot, Josep-María; Grau, Oriol; Carrillo, Empar; Guàrdia, Roser; Lluent, Artur
In mid-latitude mountains, snowbeds often consist of small, scattered alpine belt units that host many plants of high biogeographic interest. Because most snowbed species are weak competitors, it is important to study the dissemination and persistence of their seeds to better understand their population dynamics. This study analyzed the snowbed flora of the Central Pyrenees using 11 morpho-functional traits, mostly related to seed function. The seeds of most plants found in snowbeds are small or very small, they have ovoid to elliptical shapes, and have no attributes related to dispersal. When only snowbed specialists (i.e., with a phytosociological optimum in...
6.
Species Diversity and Life-Form Patterns in Steppe Vegetation along a 3000 m Altitudinal Gradient in the Alborz Mountains, Iran - Mahdavi, Parastoo; Akhani, Hossein; Van der Maarel, Eddy
Biodiversity pattern and life-form spectra were studied along a 3,000 m altitudinal gradient from a semi-desert area to the alpine peak of Tochal Mountain. The gradient is located on the southern slopes of Central Alborz with a Mediterranean continental climate. DCA ordination was applied to 1,069 relevés and 7 quantitative variables to discover the relation of diversity and altitude. A biodiversity pattern was obtained by relating values for species richness and Shannon-Wiener�s index to 100-m altitudinal sections. Altitude was determined as the major ecological gradient. Both diversity indices are negatively correlated with altitude and show a decreasing trend beyond a...
8.
Laboratory simulation experiment on dissolution of limestone under hydrodynamic pressure - Liu, Qi; Lu, Yaoru; Zhang, Feng
To study the dissolution mechanisms of limestone driven by hydrodynamic reservoir pressure during different storage periods, a simulation experiment on the limestone in a hydropower station of Wujiang River in China was performed. Using a set of specially designed pressure corrosion equipment in an open system, the experiment simulated the dissolution process of limestone under hydrodynamic pressure (0-2.0 MPa) and temperature (15-85 °C). Results show that the amount of dissolution and its rate increase with hydrodynamic pressure and rising temperature, as a result the curve of dissolution rate is obviously changed. In addition, dissolution of carbonate rocks includes both chemical...
9.
A Review of Reef Restoration and Coral Propagation Using the Threatened Genus Acropora in the Caribbean and Western Atlantic - Young, C.N.; Schopmeyer, S.A.; Lirman, D.
Coral reef restoration has gained recent popularity in response to the steady decline of corals and the recognition that coral reefs may not be able to recover naturally without human intervention. To synthesize collective knowledge about reef restoration focused particularly on the threatened genus Acropora in the Caribbean and western Atlantic, we conducted a literature review combined with personal communications with restoration practitioners and an online questionnaire to identify the most effective reef restoration methods and the major obstacles hindering restoration success. Most participants (90%) strongly believe that Acropora populations are severely degraded, continue to decline, and may not recover...
10.
Rapid Invasion of Indo-Pacific Lionfishes (Pterois Volitans and Pterois Miles) in the Florida Keys, USA: : Evidence from Multiple Pre- and Post-Invasion Data Sets - Ruttenberg, Benjamin I.; Schofield, Pamela J.; Akins, J. Lad; Acosta, Alejandro; Feeley, Michael W.; Blondeau, Jeremiah; Smith, Steven G.; Ault, Jerald S.
Over the past decade, Indo-Pacific lionfishes, Pterois volitans (Linnaeus, 1758) and Pterois miles (Bennett, 1828), venomous members of the scorpionfish family (Scorpaenidae), have invaded and spread throughout much of the tropical and subtropical northwestern Atlantic Ocean and Caribbean Sea. These species are generalist predators of fishes and invertebrates with the potential to disrupt the ecology of the invaded range. Lionfishes have been present in low numbers along the east coast of Florida since the 1980s, but were not reported in the Florida Keys until 2009. We document the appearance and rapid spread of lionfishes in the Florida Keys using multiple...
11.
Dynamics of an Acute Coral Disease Outbreak Associated with the Macroalgae Dictyota spp. in Dry Tortugas National Park, Florida, USA - Brandt, Marilyn E.; Ruttenberg, Benjamin I.; Waara, Rob; Miller, Jeff; Witcher, Brian; Estep, Andrew J.; Patterson, Matt
Reports of coral disease outbreaks have increased in recent decades, but often few details are known about these outbreaks, such as environmental triggers, associated biological variables, or even the precise temporal span of the outbreak. Here we document an acute outbreak of a rapid tissue loss disease on the highest live coral cover (15%-30%) reefs within Dry Tortugas National Park, Florida, USA. This disease exhibited similar signs to white plague disease with the notable exception that a white film often was observed on the recently denuded skeleton. The temporal span of the disease was short (<2 mo). Partial mortality was...
12.
Notula ad Floram paraquaiensem, 106 - Ramella, Lorenzo; Perret, Patrick
Thirty-fifth installment of a series dedicated to the presentation of taxonomic, nomenclatural or floristic novelties in relation with the project �Flora del Paraguay� as well as complements to already published treatments. Organizational
information and accounts on the advancement of the project are sometimes added by the editors. � Notula 106. Synopsis and typifications of the species of the genus Oxypetalum R. Br. (Asclepiadaceae) in Paraguay, by Jorge Fontella Pereira, Sergio A. Cáceres Moral & Monique Britto de Goes. The authors present a key and a synopsis of the 31 species and 3 infraspecific taxa of the genus Oxypetalum R. Br. in...
13.
alicioid lichens and fungi in the Muota Valley, central Switzerland: high species diversity in a small area - Groner, Urs
An inventory of the calicioid lichens and fungi of the Bödmeren Forest region in the Muota Valley, central Switzerland, produced no less than 51 lichenized and non-lichenized taxa on bark and wood. This mainly subalpine spruce forest in the Prealps hosts the most diverse calicioid flora in Switzerland today and a similarly rich flora from a comparably small are ais unknown from neighbouring countries. Calicium denigratum (Vain.) Tibell and Chaenothecopsis oregano Rikkinen are new to Switzerland. Calicium adaequatum Nyl., Chaenothecopsis tasmanica Tibell and Chaenothecopsis vainioana (Nádv.) Tibell are also reported for the first time from this region. Chaenotheca chrysocephala (Ach.)...
14.
Notes on the flora of Madagascar, 1-5 - Callmander, Martin W.; Phillipson, Peter B.; Gautier, Laurent
Ongoing research on Madagascar's flora is revealing numerous taxonomic novelties and nomenclatural inconsistencies, and providing new data on species distribution. This is the first article in a series that aims to provide the botanical community working on the flora of Madagascar an opportunity to publish short communications on these topics.
- Note 1. Dealingwith Indigofera nivea (Leguminosae) - a new name for Madagascar and a new combination for Africa, by Martin W. Callmander, Jean-Noël Labat & Brian D. Schrire. The authors resolve the application of "Indigofera nivea". Indigofera nivea Spreng. is a valid name for an African species now referred...
15.
The endemic vascular flora of Supramontes (Sardinia), a priority plant conservation area - Fenu, Giuseppe; Mattana, Efisio; Congiu, Angelino; Bacchetta, Gianluigi
The main aim of this work is to present a checklist of the endemic vascular flora of the Supramontes region (Central Eastern Sardinia) in order to classify this area in the Sardinian biogeographic subprovince and to better assess its conservation priorities. It is one of the most interesting regions of the Island and spreads for335 km2from the inland limestone massif to the Orosei gulf. This work was based on bibliographic and herbarium studies, integrated by several field surveys carried out from 2004 to 2009. In this study 138 endemic taxa, belonging to 98 genera and 42 families, have been found,...
16.
Taxonomical revision of the species of the genus Schizachyrium Nees (Poaceae: Andropogoneae) of South America - Peichoto, Myriam C.
These "notes" deal with 102 noteworthy taxa amongst which 12 are new introduced species to the island's flora: Chamaerops humilis, Bothriochloa barbinodis, Anthemis cretica subsp. cretica, Arctotheca calendula, Crepis nicaeensis, Leontodon hispidus subsp. hispidus, Soliva sessilis, Saponaria ocymoides subsp. ocymoides, Silene italica, Euphorbia cyparissias, Anthyllis vulneraria subsp. carpatica and Physalis peruviana. New localities are given on one hand for 39 taxa considered as "very rare" (RR) out of which 9 (Freesia alba, Serapias strictiflora, Elytrigia repens, Hordeum marinum subsp. marinum, Crepis bursifolia, Crepis foetida subsp. rhoedifolia, Gleditsia triacanthos, Fumaria flabellata and Galium minutulum) become "rare" (R). On the other hand...
18.
Notes et contributions à la flore de Corse, XXIII - Jeanmonod, Daniel; Schlüssel, André
These "notes" deal with 102 noteworthy taxa amongst which 12 are new introduced species to the island's flora: Chamaerops humilis, Bothriochloa barbinodis, Anthemis cretica subsp. cretica, Arctotheca calendula, Crepis nicaeensis, Leontodon hispidus subsp. hispidus, Soliva sessilis, Saponaria ocymoides subsp. ocymoides, Silene italica, Euphorbia cyparissias, Anthyllis vulneraria subsp. carpatica and Physalis peruviana. New localities are given on one hand for 39 taxa considered as "very rare" (RR) out of which 9 (Freesia alba, Serapias strictiflora, Elytrigia repens, Hordeum marinum subsp. marinum, Crepis bursifolia, Crepis foetida subsp. rhoedifolia, Gleditsia triacanthos, Fumaria flabellata and Galium minutulum) become "rare" (R). On the other hand...
19.
Taxonomic revision of Sinningia Nees (Gesneriaceae) IV : six new species from Brazil and a long overlooked taxon - Chautems, Alain; Lopes, Thereza Cristina Costa; Peixoto, Mauro; Rossini, Josiene
Six espèces nouvelles du genre Sinningia Nees sont décrites: Sinningia bullata Chautems & M. Peixoto, Sinningia canastrensis Chautems, Sinningia gerdtiana Chautems, Sinningia globulosa Chautems & M. Peixoto, Sinningia helioana Chautems & Rossini et Sinningia muscicola Chautems, T. Lopes & M. Peixoto. Une espèce considérée tout d'abord comme inédite est identifiée comme Sinningia polyantha (DC.)Wiehler. Des commentaires sur les relations phylogénétiques au sein de la tribu des Sinningieae Fritsch, ainsi que sur l'écologie et le statut de conservation, sont également présentés. Chaque espèce est illustrée et sa répartition géographique est donnée.
20.
A taxonomic revision of Timonius subgen. Pseudobobea (Valeton) S. P. Darwin (Rubiaceae) - Darwin, Steven P.
Twenty-one species, distributed from Sulawesi (Indonesia) to Rossel Island (Louisiade Archipelago) through the Moluccas(Indonesia) and Papua New Guinea, are assigned to Timoniussubgen. Pseudobobea (Valeton) S. P. Darwin, a new taxon basedon Timonius sect. Pseudobobea Valeton (Rubiaceae, Guettardeae). Nine new species are described: Timonius akunensisS. P. Darwin, Timonius bracteoides S. P. Darwin, Timonius carrii S. P. Darwin, Timonius clathratus S. P. Darwin, Timonius leptocalyx S. P. Darwin, Timonius moluccanus S. P. Darwin,Timonius reflexus S. P. Darwin, Timonius repertus S. P. Darwin,and Timonius rosselensis S. P. Darwin. Species of the new subgenus are distinctive in having usually vertically oriented fruit pyrenes, reflexed...
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