Search results for " Systematics"
showing 10 items of 6576 documents
Range-wide phylogeography and taxonomy of the marine rock pools dweller Tigriopus fulvus (Fischer, 1860) (Copepoda, Harpacticoida)
2021
In the light of the wide distribution and ecological importance of the genus Tigriopus in coastal rock pool habitats, and of its frequent use in aquaculture and as a model organism, we investigated the identity of the Atlantic–Mediterranean Tigriopus populations and elucidated their taxonomy and patterns of morphological and genetic diversity. In order to reach these goals, an “integrative taxonomy” multisource approach was implemented. First, we investigated the constancy and taxonomical value of the morphological characters currently used to distinguish among the Tigriopus species occurring in the Mediterranean and in Eastern Atlantic area north of the Tropic of Cancer, and checked the ac…
Environmental and spatial correlates of community composition, richness and status of boreal lake macrophytes
2013
Abstract We assessed the relative roles of natural covariates, human disturbance (water quality and catchment land use) together with geography in driving variation in aquatic macrophyte community composition, richness and status among 101 lakes in southern and central Finland. In addition to all species together, we studied different growth forms (i.e. emergent and submerged macrophytes and aquatic bryophytes) separately. Partial redundancy analysis (taxonomic composition) and partial least-squares regression (species richness and status index) were employed to display the share of variability in macrophyte assemblages that was attributable to the environmental factors (both natural and hu…
Mid-Holocene forests from Eastern Hungary: New anthracological data
2013
Charcoal remains found in five archaeological sites provided an important source of information about the woody vegetation that developed during the Atlantic period in eastern Hungary. The results are presented jointly since all sites are located in very similar habitats, they reflect Neolithic cultures and present comparable floral compositions. The reconstruction of past forest communities from the Great Hungarian Plain in the Atlantic period is based on pollen analysis and new anthracological data offer significant complementary information to the established pollen sequences. These data were obtained from more than 5000 charcoal fragments in which 28 taxa were identified. The main contr…
The effect of vegetation structure on seasonal density of Sylvia warblers in the eastern Iberian Peninsula
2021
Vegetation characteristics determine seasonal habitat selection by Eurasian Blackcaps Sylvia atricapilla, Dartford Warblers Sylvia undata, and Sardinian Warblers Sylvia melanocephala, and changes i...
New Data on Orthotrichum gigantosporum Lewinsky (Orthotrichaceae, Bryophyta), a Widespread Northern Andean-Patagonian Endemic Moss
2021
The moss family Orthotrichaceae is still poorly known in the southern extreme of South America. This is especially true regarding the morphological variability, geographical distribution, and ecological affinities of the species restricted to the Andean-Patagonian area. These deficiencies are addressed for Orthotrichum gigantosporum Lewinsky, one of the least known and most interesting endemics of the area. After examining the rich collections made by our team in southern Chile and Argentina, we have found numerous new localities for the species. Orthotrichum gigantosporum has proven to be a widespread moss in the forests and scrublands of the northern sector of the Andean-Patagonian area. …
Pre-Migratory Movements of Adult Montagu's HarriersCircus pygargus
2008
Pre-migratory and migratory movements of Montagu's Harrier Circus pygargus, a long-distance migrant, are poorly documented by ring recoveries and observations. In the present study, we tagged 10 adult Montagu's Harriers in NE Spain with satellite transmitters and tracked their movements until their arrival on the wintering grounds. To identify the end of the breeding season and the onset of the migration based on our satellite-telemetry data we developed and applied a statistical approach, defining the time period between these two events as the pre-migratory stage. We then compared habitat preferences during the breeding season and the pre-migratory stage. The duration of the pre-migratory…
The Role of Spatial Exploration and Territoriality in Establishing Gilthead Seabream (Sparus aurata) Hierarchies, and Their Effects upon Underlying S…
2023
Territoriality, spatial exploration and social hierarchy are strictly related behaviors in gregarious fishes, and are often under-appreciated in farms where the individuals are confined within crowded spaces. In this study, we investigated the role of spatial exploration, elucidating the importance of time upon forming the social organization, and the role of the territoriality in gilthead seabream (Sparus aurata), using two experimental approaches. In the first approach, three fish were placed sequentially in the aquarium with an interval of two days (sequential model), while in the second (simultaneous model), two fish were simultaneously placed in an aquarium divided by a barrier which w…
Microbial succession of nitrate-reducing bacteria in the rhizosphere of Poa alpina across a glacier foreland in the Central Alps
2006
International audience; Changes in community structure and activity of the dissimilatory nitrate-reducing community were investigated across a glacier foreland in the Central Alps to gain insight into the successional pattern of this functional group and the driving environmental factors. Bulk soil and rhizosphere soil of Poa alpina was sampled in five replicates in August during the flowering stage and in September after the first snowfalls along a gradient from 25 to 129 years after deglaciation and at a reference site outside the glacier foreland (> 2000 years deglaciated). In a laboratory-based assay, nitrate reductase activity was determined colorimetrically after 24 h of anaerobic inc…
A luminal glycoprotein drives dose-dependent diameter expansion of the Drosophila melanogaster hindgut tube
2012
An important step in epithelial organ development is size maturation of the organ lumen to attain correct dimensions. Here we show that the regulated expression of Tenectin (Tnc) is critical to shape the Drosophila melanogaster hindgut tube. Tnc is a secreted protein that fills the embryonic hindgut lumen during tube diameter expansion. Inside the lumen, Tnc contributes to detectable O-Glycans and forms a dense striated matrix. Loss of tnc causes a narrow hindgut tube, while Tnc over-expression drives tube dilation in a dose-dependent manner. Cellular analyses show that luminal accumulation of Tnc causes an increase in inner and outer tube diameter, and cell flattening within the tube wall,…
Anaerobic Degradation of the Invasive Weed Solidago canadensis L. (goldenrod) and Copper Immobilization by a Community of Sulfate-Reducing and Methan…
2023
The weed Solidago canadensis L. poses a global threat to the environment as it spreads uncontrollably on roadsides, in forests, fields, meadows, and farmland. Goldenrod emits toxic substances that suppress other plants on the site, displacing wild ones. Thus, goldenrod conquers huge areas very quickly. The use of herbicides and mechanical methods does not solve the problem of the spontaneous spread of goldenrod. On the other hand, many scientists consider goldenrod as a valuable source of biologically active substances: flavonoids, phenolic compounds, vitamins, etc. In this study, we consider Solidago plants as a promising, free (cheap), and renewable substrate for the production of methane…