Search results for "rct"
showing 10 items of 1934 documents
Comparative biogeography of echinoids, bivalves and gastropods from the Southern Ocean.
2013
ABSTRACTAim Biogeographical patterns within three classes, the Echinoidea, Bivalvia andGastropoda, were investigated in Antarctic, sub-Antarctic and cold-temperateareas based on species occurrence data. Faunal similarities among regions wereanalysed to: (1) test the robustness of the biogeographical patterns previouslyidentified in bivalves and gastropods; (2) compare them with the biogeographi-cal patterns identified for echinoids; and (3) evaluate the reliability of the bio-geographical provinces previously proposed, depending on the taxa andtaxonomic levels analysed.Location The Southern Ocean, sub-Antarctic islands and cold-temperate areassouth of 45° S latitude at depths of < 1000 m.Meth…
Introduction of Mysis relicta (Mysida) reduces niche segregation between deep-water Arctic charr morphs
2019
This is a post-peer-review, pre-copyedit version of an article published in Hydrobiologia. The final authenticated version is available online at https://doi.org/10.1007/s10750-019-3953-4. Niche diversification of polymorphic Arctic charr can be altered by multiple anthropogenic stressors. The opossum-shrimp (Mysis relicta) was introduced to compensate for reduced food resources for fish following hydropower operations in Lake Limingen, central Norway. Based on habitat use, stomach contents, stable isotopes (δ13C, δ15N) and trophically transmitted parasites, the zooplanktivorous upper water-column dwelling ‘normal’ morph was clearly trophically separated from two sympatric deep-water morphs…
Trophic interactions between introduced lake trout (Salvelinus namaycush) and native Arctic charr (S. alpinus) in a large Fennoscandian subarctic lake
2014
Introduced fishes may have major impacts on community structure and ecosystem function due to competitive and predatory interactions with native species. For example, introduced lake trout (Salvelinus namaycush) has been shown to replace native salmonids and induce major trophic cascades in some North American lakes, but few studies have investigated trophic interactions between lake trout and closely related native Arctic charr (S.alpinus) outside the natural distribution of the former species. We used stomach content and stable isotope analyses to investigate trophic interactions between introduced lake trout and native Arctic charr in large subarctic Lake Inarijarvi in northern Finland. …
Female brown bears use areas with infanticide risk in a spatially confined population
2020
Areas used by female brown bears (Ursus arctos) with cubs-of-the-year (hereafter, FCOY) during the first months after den exit are crucial for offspring survival, primarily because of the risk of infanticide by male bears. Therefore, FCOY may avoid areas frequented by adult males during the mating season. The main aim of this study was to identify landscape features (i.e., structure, composition, and human footprint) that may differentiate the habitat use of FCOY in the small bear population of the Cantabrian Mountains (northwestern Spain; 2001–2016) from (a) areas frequented by females with yearlings, because older cubs are at less risk of infanticide than cubs-of-the-year, and (b) bear ma…
Description of the sexual generation of Dryocosmus destefanii (Hymenoptera: Cynipidae: Cynipini) and disclosure of its life cycle
2020
The sexual generation of Dryocosmus destefanii Cerasa & Melika, 2018 that emerges from galls on Q. suber L. in Italy is described for the first time, establishing its heterogonic life cycle. We provide observations on its distribution, illustration of adults and galls and information on its biology as supported by morphological and molecular data. An illustrated identification key to Western Palaearctic Dryocosmus species is also given.
New and poorly known Holarctic species of Boletina Staeger, 1840 (Diptera, Mycetophilidae)
2016
The genus Boletina is a species rich group of fungus gnats. Members of the genus are mainly known from temperate, boreal and arctic biomes. Phylogeny of the genus is still poorly resolved, dozens of species are insufficiently described and undescribed species are often discovered, especially from samples taken from the boreal zone. Four new species are described. Boletina valteri Salmela sp.n. (Finland), Boletina kullervoi Salmela sp.n. (Finland), B. hyperborea Salmela sp.n. (Finland, Norway, Sweden, Canada) and B. nuortti Salmela sp.n. (Finland). Boletina arctica Holmgren is redescribed and reported for the first time from the Canadian high arctic zone. Boletina borealis Zetterstedt and B.…
Biodiversity change after climate-induced ice-shelf collapse in the Antarctic
2011
Julian Gutt ... et al. -- 10 pages, 5 figures, 1 table, supplementary data https://doi.org/10.1016/j.dsr2.2010.05.024
Biogeochemical cycling and ecological thresholds in a High Arctic lake (Svalbard)
2019
Lakes are a dominant feature of the Arctic landscape and a focal point of regional and global biogeochemical cycling. We collected a sediment core from a High Arctic Lake in southwestern Svalbard for multiproxy paleolimnological analysis. The aim was to find linkages between the terrestrial and aquatic environments in the context of climate change to understand centennial-long Arctic biogeochemical cycling and environmental dynamics. Two significant thresholds in elemental cycling were found based on sediment physical and biogeochemical proxies that were associated with the end of the cold Little Ice Age and the recent warming. We found major shifts in diatom, chironomid and cladoceran comm…
Introgression of mitochondrial DNA among Myodes voles: consequences for energetics?
2011
Abstract Background Introgression of mitochondrial DNA (mtDNA) is among the most frequently described cases of reticulate evolution. The tendency of mtDNA to cross interspecific barriers is somewhat counter-intuitive considering the key function of enzymes that it encodes in the oxidative-phosphorylation process, which could give rise to hybrid dysfunction. How mtDNA reticulation affects the evolution of metabolic functions is, however, uncertain. Here we investigated how morpho-physiological traits vary in natural populations of a common rodent (the bank vole, Myodes glareolus) and whether this variation could be associated with mtDNA introgression. First, we confirmed that M. glareolus ha…
Deep divergence and evidence for translocations between Iranian and European populations of the alfalfa weevil (Coleoptera: Curculionidae) based on m…
2016
AbstractThe alfalfa weevil (Hypera postica(Gyllenhal): Coleoptera: Curculionidae) is an invasive pest of alfalfa (Medicago sativaLinnaeus; Fabaceae) in the Holarctic region. Across the wide geographic distribution of the species different local adaptions have been observed. Further, several distinct mitochondrial lineages have been discovered, which have been treated as western and Egyptian/eastern strains. However, our knowledge of the biogeography ofH. posticais largely limited to North American and Japanese populations. We sampled the species from four locations in Iran and two countries in Europe (Poland and Czech Republic) and sequenced the mitochondrial COI gene to detect patterns of …