Search results for "Systematics"
showing 10 items of 6702 documents
First records of complete annual cycles in water rails Rallus aquaticus show evidence of itinerant breeding and a complex migration system
2020
Abstract In water rails Rallus aquaticus, northern and eastern populations are migratory while southern and western populations are sedentary. Few details are known about the annual cycle of this elusive species. We studied movements and breeding in water rails from southernmost Norway where the species occurs year-round. Colour-ringed wintering birds occurred only occasionally at the study site in summer, and vice versa. Geolocator tracks revealed that wintering birds (n = 10) migrated eastwards in spring to breed on both sides of the Baltic Sea, whereas a single breeding bird from the study site wintered in north Italy. Ambient light records of geolocator birds further indicated that all …
In silico evaluation of molecular probes for detection and identification of Ralstonia solanacearum and Clavibacter michiganensis subsp. sepedonicus.
2004
Ralstonia solanacerum and Clavibacter michiganensis subsp. sepedonicus are the two most relevant bacterial pathogens of potato for which a large number of molecular diagnostic methods using specific DNA sequences have been developed. About one hundred oligonucleotides have been described and thoroughly tested experimentally. After having compiled and evaluated all these primers and probes in silico to check their specificity, many discrepancies were found. A detailed analysis permitted the recognition of different possible reasons for such discrepancies: sequencing errors in public sequences, wrong supposed specificity (sometimes due to more recent sequences than the oligonucleoticles being…
Hybridization within the Rana ridibunda Complex of North Africa
1980
Abstract Cellogel electrophoretic study of the plasma protein pattern, especially the albumin fractions, and microdensitometric determination of erythrocyte nuclear DNA amount in 25 frogs of the Rana ridibunda complex from different localities in Morocco and Algeria allows the conclusion that two different forms of this complex are hybridizing in North Africa, as it is found in the Rana esculenta complex in Europe or in the East Asian green frogs. These forms can be identified by their albumin alleles, but not yet by their morphology. They produce mainly triploid hybrids.
Determinants of macroinvertebrate diversity in headwater streams: regional and local influences
2003
Summary 1 Multiscale determinants of diversity and the relationship between regional (RSR) and local richness (LSR) have recently attracted increased attention, yet such studies on stream organisms remain scarce. We studied the relationships among RSR, β-diversity, LSR and local environmental variables in 120 headwater streams in Finland. Approximately similar-sized areas of eight drainage systems were defined as regions, and 15 stream riffles (= locality) per region were sampled. 2 RSR showed a strong positive relationship with mean LSR (R2 = 0·686), and there was no sign of curvilinearity within the observed range of RSR. RSR was also positively, although non-significantly, related to β-d…
Invasion genetics of American cherry fruit fly in Europe and signals of hybridization with the European cherry fruit fly
2013
The American cherry fruit fly is an invasive pest species in Europe, of serious concern in tart cherry productionaswellasforthepotentialtohybridizewiththeEuropeancherryfruitfly,Rhagoletiscerasi L. (Diptera: Tephritidae), which might induce new pest dynamics. In the first European reports, the question arose whether only the eastern American cherry fruit fly, Rhagoletis cingulata (Loew) (Diptera: Tephritidae), is present, or also the closely related western American cherry fruit fly, Rhagoletis indifferens Curran. In this study, we investigate the species status of European populations by comparing these with populations of both American species from their native ranges, the invasion dynamic…
On the mend of bryophyte conservation in Spain: preparing a proposal for the inclusion of bryophytes in national species protection catalogues
2018
The Spanish bryoflora contains 1291 taxa, 272 of them included in the Spanish Red List under any threat category. Although bryophytes show a low rate of endemicity compared to vascular flora, Spanish administration’s responsibility for the conservation of these plants is very high, since the country has 63 exclusive or rare species on a European or world scale. However, the representation of this group of plants in the Spanish legislation on species conservation is merely anecdotal. Royal Decree 139/2011 of 4 February develops a list of wild protected species (LESRPE and CEEA, Spanish abbreviations) and includes only 10 species of bryophytes, all of them from the Directive Habitats and the …
A statistical analysis of the three-fold evolution of genomic compression through frame overlaps in prokaryotes
2007
Abstract Background Among microbial genomes, genetic information is frequently compressed, exploiting redundancies in the genetic code in order to store information in overlapping genes. We investigate the length, phase and orientation properties of overlap in 58 prokaryotic species evaluating neutral and selective mechanisms of evolution. Results Using a variety of statistical null models we find patterns of compressive coding that can not be explained purely in terms of the selective processes favoring genome minimization or translational coupling. The distribution of overlap lengths follows a fat-tailed distribution, in which a significant proportion of overlaps are in excess of 100 base…
Holidays? Not for all. Eagles have larger home ranges on holidays as a consequence of human disturbance
2019
Human-wildlife conflicts are the object of raising concern in conservation biology. People living in urban areas are rapidly increasing worldwide and consequently the temporal pattern of occupation of natural areas for recreation is changing as well, resulting in an ever-increasing concentration of people during weekends and holidays. This is particularly evident in affluent societies, where more recreationists visit natural areas on holidays and weekends, causing disturbance to wildlife in the so-called “weekend effect”. Here, we tested the response to disturbance of 30 Bonelli's eagles tracked by high-frequency GPS/GSM telemetry. We analysed daily home-range size, a measure of changing be…
Stable isotope composition and rare earth element content of vertebrate remains from the Late Cretaceous of northern Spain (Laño): did the environmen…
2003
Abstract Oxygen and carbon isotope measurements have been performed on phosphatic remains from faunal associations (dinosaurs, crocodiles, turtles and fish) of the Late Cretaceous continental and marine sediments from northern Spain (Basque Country). The environmental meaning of the oxygen isotope record in fossil reptiles is discussed on the basis of known paleoecology, modern fauna analogs, and apatite chemistry (rare earth elements (REE), CO32− and PO43− contents). Fossil remains in sandstones and argillites from two localities (Urria and Cuezva) have low (down to 16‰) and scattered δ18O(PO4,CO3) and δ13C values with REE patterns characterized by strong middle REE enrichments. These geoc…
Cyclicity of Triassic to Lower Jurassic continental red beds of the Argana Valley, Morocco: implications for palaeoclimate and basin evolution
2000
Abstract Cyclical playa deposits form a prominent part of the continental clastic succession of the Argana Valley, Western High Atlas of Morocco. The red beds formed in Triassic to Lower Jurassic times during rifting of the North American and African plates. Detailed stratigraphic work revealed asymmetrical, metre-scale cycles in mudstone-dominated successions that constitute the intermediate and upper portion of the basin fill. Sedimentary cycles commonly comprise ephemeral lake shales at the base, playa mudflat mudstones in the intermediate part, and both fluvial and aeolian sandstones at the top. Cycles of the Aglegal Member (T4) are mainly characterized by analcime-rich playa mudflat de…