27 research outputs found
El género Baldellia Parl. (Alismataceae) en la Península Ibérica, Baleares y Marruecos.
The genus Baldellia Parl. (Alismataceae) in the Iberian Peninsula, Balearic Island and MoroccoPalabras clave. Baldellia repens, taxones infraespecíficos, W mediterráneo.Key words. Baldellia repens, infraespecific taxa, W mediterranean
Attract them anyway: benefits of large, showy flowers in a highly autogamous, carnivorous plant species
Reproductive biology of carnivorous plants has largely been studied on species that rely on insects as pollinators and prey, creating potential conflicts. Autogamous pollination, although present in some carnivorous species, has received less attention. In angiosperms, autogamous self-fertilization is expected to lead to a reduction in flower size, thereby reducing resource allocation to structures that attract pollinators. A notable exception is the carnivorous pyrophyte Drosophyllum lusitanicum (Drosophyllaceae), which has been described as an autogamous selfing species but produces large, yellow flowers. Using a flower removal and a pollination experiment, we assessed, respectively, whether large flowers in this species may serve as an attracting device to prey insects or whether previously reported high selfing rates for this species in peripheral populations may be lower in more central, less isolated populations. We found no differences between flower-removed plants and intact, flowering plants in numbers of prey insects trapped. We also found no indication of reduced potential for autogamous reproduction, in terms of either seed set or seed size. However, our results showed significant increases in seed set of bagged, hand-pollinated flowers and unbagged flowers exposed to insect visitation compared with bagged, non-manipulated flowers that could only self-pollinate autonomously. Considering that the key life-history strategy of this pyrophytic species is to maintain a viable seed bank, any increase in seed set through insect pollinator activity would increase plant fitness. This in turn would explain the maintenance of large, conspicuous flowers in a highly autogamous, carnivorous plant
Big thistle eats the little thistle: does unidirectional introgressive hybridization endanger the conservation of Onopordum hinojense?
Hybridization is known to have a creative role in plant evolution. However, it can also have negative effects on parental species. Onopordum is a large genus whose species frequently hybridize. In the Southwest Iberian Peninsula, the rare O. hinojense co-occurs with the widely distributed O. nervosum, and hybrids between these two taxa have been described as O. × onubense.
In this study we determine the extinction risk in a hybrid zone, both for hybrids and parentals, using analyses of morphological and cytogenetic traits as well as genetic markers and demographic models. To investigate the introgression process we used amplified fragment length polymorphism (AFLP) markers, Bayesian analyses and genome scan methods.
Morphology, genome size and molecular markers confirmed homoploid hybridization and also indicated unidirectional backcrossing of F1 hybrids with O. nervosum, which is likely to swamp O. hinojense, the parental with lower pollen size and a very low fruit set (8%). Genome scan methods revealed several loci significantly deviating from neutrality. Finally, our demographic modeling indicated that the higher fitness of O. nervosum threats the survival of O. hinojense by demographic swamping.
Our study provides strong new evidence for a scenario of rapid extinction by unidirectional introgression and demographic swamping. The multifaceted approach used here sheds new light on the role of introgression in plant extinctions
Dos especies nuevas del género Onopordum L. del litoral atlántico (SW de España y NW de Marruecos).
Two new species of genus Onopordum L. from the Atlantic coast (SW Spain and NW Morocco)Palabras clave. Onopordum, Compositae, costa atlántica, W Mediterráneo.Key words. Onopordum, Compositae, Atlantic coast, W Mediterranean
El ciervo en Andalucía
El ciervo o venado —término más cinegético— se asienta principalmente en el arco montañoso, de altitud media y de pendiente suave, que recorre Andalucía de noreste a sureste, desde la provincia de Jaén hasta la de Huelva, pasando por Córdoba y Sevilla. Se denomina Sierra Morena a este accidente orográfico y el nombre, en la eti- mología más común, parece responder a su color característico. La vocación de esta sierra históricamente y, en la actualidad, es agrosilvocinegéti- ca. Los tres elementos de esta palabra compuesta han oscilado en su proporción a lo largo del tiempo, según la coyuntura, y en función de las características edáficas —las climáticas son más uniformes— se reparten los aprovechamientos en un mosaico no excesivamente complejo. El paisaje, a veces, se abre en valles, el más típico y amplio el de Los Pedroches, donde la componente agrícola y ganadera es el aprovechamiento casi exclusivo hasta el día de hoy, en el que la coyuntura comienza a cambiar, y se inicia la reforestación que significará un cambio acaso importante, y el principio del regreso a los orígenes. Si el monte aumenta su densidad, y sobre todo la mancha de matorral se cierra y ocupa áreas significativas, entonces la vocación o especialización prioritaria es la cinegética. El hábitat es, sin duda, idóneo y apropiado para que se asiente y desarrolle el ciervo, junto con otras especies, como puede ser el jabalí, el gamo y la cabra mon- tés y doméstica, o aún el corzo en su nicho natural de la Sierra de Cádiz. Lo dicho es característico en conocidas zonas de Jaén, Córdoba y Sevilla. En otras ocasiones, el hábitat natural ha sido transformado artificialmente por plantaciones de pinos y de eucaliptus, particularmente en Huelva y en áreas puntuales de las otras provincias. El aprovechamiento selvícola artificial e intensivo dificulta el desarrollo de la cubierta vegetal y, por ello, no permite que las especies cinegéticas se asienten de modo permanente si no existen zonas próximas del típico hábitat y monte mediterráneo
Genotypic identification of an undescribed spotted fever group rickettsia in ixodes ricinus from southwestern Spain
An undescribed rickettsia was directly analyzed with specific rickettsial molecular biology tools on Ixodes ricinus L. collected in different localities of the province of Cadiz (southwestern Spain). On the basis of the
results of the citrate synthase (glta) gene, 190 kD-outer membrane protein (rOmpA) gene, and 16S ribosomal RNA (16S rRNA) gene partial sequence data, it was found that this rickettsia is sufficiently genetically distinct from other Rickettsia to be considered a distinct taxonomic entity. The isolation and culture of this organism, as well as comparative antigenic analysis, are required to ensure its conclusive taxonomic placement among spotted fever rickettsiae.
The epidemiologic role of this new rickettsial agent and its possible pathogenicity to wild and domestic animals or humans is still unknown and needs to be investigated
Riverine speciation and long dispersal colonization in the Ibero-African Onopordum dissectum complex (Asteraceae)
In the western Mediterranean, although considerable attention has focused on the role of the Strait of Gibraltar on diversification of biota, relatively few studies have looked at the biogeographical consequences of the large rivers as barriers to gene flow on North African and southern European taxa. To investigate the importance of river basins in phylogeographical patterns, we took the Onopordum dissectum complex (Asteraceae) as a model. This is an Iberian-Moroccan endemic group, which currently includes four taxa: O. hinojense, O. magrebiense, O. murbeckii and O. dissectum. The nrDNA analysis resulted in a poorly resolved phylogenetic tree, but corroborated the monophyly of the O. dissectum complex, which also included O. macracanthum and O. nogalesii. The amplified fragment length polymorphism phylogram and the Bayesian assignment analysis showed that the O. dissectum complex is composed of four distinct genetic lineages. Analysis of molecular variance results supported the idea that Moroccan interfluves have had strong biogeographical impacts on the genetic diversity and structure of the O. dissectum complex. Our analyses suggested that this species complex originated in southern Morocco, and spread and diversified northwards in a stepping stone fashion. Northward migration would have resulted in genetic isolation and loss of genetic diversity, especially detectable in the South Iberian populations. Our findings suggest that the development of the major river systems in the western Mediterranean region shaped the genetic structure of Onopordum populations during the Quaternary and promoted species diversification, as enunciated in the riverine barrier hypothesi
Phylogeography above the species level for perennial species in a composite genus
In phylogeography, DNA sequence and fingerprint data at the population level are used to infer evolutionary histories of species. Phylogeography above the species level is concerned with the genealogical aspects of divergent lineages. Here, we provide a phylogeographic study to examine the evolutionary history of a western Mediterranean composite, focusing on the perennial species of Helminthotheca (Asteraceae, Cichorieae). We used molecular markers (AFLP; ITS and plastid DNA sequences) to infer relationships among populations throughout the distributional range of the group. Interpretation is aided by biogeographic and molecular clock analyses. Four coherent entities are revealed by Bayesian mixture clustering of AFLP data, which correspond to taxa previously recognized at the rank of subspecies. The origin of the group was in western North Africa, from where it expanded across the Strait of Gibraltar to the Iberian Peninsula and across the Strait of Sicily to Sicily. Pleistocene lineage divergence is inferred within western North Africa as well as within the western Iberian region. The existence of the four entities as discrete evolutionary lineages suggests that they should be elevated to the rank of species, yielding H. aculeata, H. comosa, H. maroccana and H. spinosa, whereby the latter two necessitate new combinations