Search results for "extinction"
showing 8 items of 458 documents
Catastrophic Population Declines and Extinctions in Neotropical Harlequin Frogs (Bufonidae: Atelopus)1
2005
We surveyed the population status of the Neotropical toad genus Atelopus, and document recent catastrophic declines that are more severe than previously reported for any amphibian genus. Of 113 species that have been described or are candidates for description, data indicate that in 42 species, population sizes have been reduced by at least half and only ten species have stable populations. The status of the remaining taxa is unknown. At least 30 species have been missing from all known localities for at least 8 yr and are feared extinct. Most of these species were last seen between 1984 and 1996. All species restricted to elevations of above 1000 m have declined and 75 percent have disappe…
Adolescent pre-exposure to ethanol and 3,4-methylenedioxymethylamphetamine (MDMA) increases conditioned rewarding effects of MDMA and drug-induced re…
2011
Many adolescents often take ethanol (EtOH) in combination with 3,4-methylenedioxymethylamphetamine (MDMA). In the present work, we used a mouse model to study the effect of repeated pre-exposure during adolescence to EtOH (2 g/kg), MDMA (10 or 20 mg/kg) or EtOH + MDMA on the rewarding and reinstating effects of MDMA in the conditioned place preference (CPP) paradigm. Pre-exposure to EtOH, MDMA or both increased the rewarding effects of a low dose of MDMA (1.25 mg/kg). These pre-treatments did not affect the acquisition of the CPP induced by 5 mg/kg of MDMA. However, the CPP was more persistent in mice pre-exposed to both doses of MDMA or to EtOH + MDMA20. After extinction of the CPP induced…
A new family of Odonatoptera from the continental Upper Permian: The Lapeyriidae (Lodève Basin, France)
1999
Abstract The new family Lapeyriidae of Odonatoptera, based on a new genus and species from the Upper Permian of Lodevois (France) is the sister group of Nodialata. It represents an evolutionary link between the venation type of the Paleozoic Meganisoptera and that of Odonata. Even if the present discovery demonstrates that the fossil record of the Odonatoptera remains imperfectly known, the present state of knowledge shows that this super order survived the mass extinction at the Permo-Triassic boundary.
Data from: Functional structure of European forest beetle communities is enhanced by rare species
2022
From article abstract: https://doi.org/10.1016/j.biocon.2022.109491 ABSTRACT Biodiverse communities have been shown to sustain high levels of multifunctionality and thus a loss of species likely negatively impacts ecosystem functions. For most taxa, however, the roles of individual species are poorly known. Rare species, often the most likely to go extinct, may have unique traits leading to unique functional roles. Alternatively, rare species may be functionally redundant, such that their loss would not disrupt ecosystem functions. We quantified the functional role of rare species by using capture records of wood-living (saproxylic) beetle species, combined with recent databases of their mo…
Data from: Revision of the genus Anasibirites Mojsisovics (Ammonoidea): an iconic and cosmopolitan taxon of the late Smithian (Early Triassic) extinc…
2016
The family Prionitidae Hyatt represents a major component of ammonoid faunas during the Smithian (Early Triassic), and the genus Anasibirites Mojsisovics is the most emblematic taxon of this family. Its stratigraphical range is restricted to the beginning of the late Smithian (Wasatchites distractus Zone). The genus is also characterized by an unusual cosmopolitan distribution, thus contrasting with most earlier Smithian ammonoid distributions that were typically restricted by latitude. Because the late Smithian witnessed an extinction of the nekton (e.g. ammonoids, conodonts) whose amplitude is equal to or larger than that of the end-Permian crisis, the number of valid species that should …
Data from: Wood-inhabiting fungi with tight associations with other species have declined as a response to forest management
2016
Research on mutualistic and antagonistic networks, such as plant–pollinator and host–parasite networks, has shown that species interactions can influence and be influenced by the responses of species to environmental perturbations. Here we examine whether results obtained for directly observable networks generalize to more complex networks in which species interactions cannot be observed directly. As a case study, we consider data on the occurrences of 98 wood-inhabiting fungal species in managed and natural forests. We specifically ask if and how much the positions of wood-inhabiting fungal species within the interaction networks influence their responses to forest management. For this, we…
HAQ survey: red QSO candidates follow-up
2015
Quasi-stellar objects (QSOs) whose spectral energy distributions (SEDs) are reddened by dust either in their host galaxies or in intervening absorber galaxies are to a large degree missed by optical color selection criteria like the ones used by the Sloan Digital Sky Survey (SDSS). To overcome this bias against red QSOs, we employ a combined optical and near-infrared (near-IR) color selection. In this paper, we present a spectroscopic follow-up campaign of a sample of red candidate QSOs which were selected from the SDSS and the UKIRT Infrared Deep Sky Survey (UKIDSS). The spectroscopic data and SDSS/UKIDSS photometry are supplemented by mid-infrared photometry from the Wide-field Infrared S…
Aircraft measurements of aerosol particles and trace gases over the Southern Baltic Sea during the BALTIC'15 campaign in 2015
2019
During the BALTIC'15 campaign, conducted in August 2015 over the Southern Baltic Sea, trace gasses (CO2/O3/NOy/SO2) and aerosol particles (number concentration of total/non-volatile/Aitken mode/ Accumulation mode/Coarse mode/refractory black carbon, aerosol extinction coefficient, mass concentration of refractory black carbon were measured). Observations were performed on board of the Alfred Wegener Institute research aircraft Polar 5 during 4 flights: - Scientific flight 1 (SF1) 26 August 2015 - Scientific flight 2 (SF2) 28 August 2015 - Scientific flight 3 (SF3) 28 August 2015 - Scientific flight 4 (SF4) 30 August 2015