Search results for " extinction"
showing 10 items of 91 documents
Suppression of extinction with TMS in humans: from healthy controls to patients.
2006
We review a series of studies exemplifying some applications of single-pulse and paired-transcranial magnetic stimulation (TMS) in the study of spatial attention and of its deficits. We will focus primarily on sensory extinction, the failure to consciously perceive a contralesional sensory stimulus only during bilateral stimulation of homologous surfaces. TMS studies in healthy controls show that it is possible either to interfere or modulate the excitability of the parietal cortex during sensory (i.e. tactile and visual) attentional tasks, thus reproducing a condition of virtual extinction. TMS studies in patients with unilateral (mainly right) brain damage show that the modulation of the …
Decreasing Phanerozoic extinction intensity as a consequence of Earth surface oxygenation and metazoan ecophysiology
2021
The decline in background extinction rates of marine animals through geologic time is an established but unexplained feature of the Phanerozoic fossil record. There is also growing consensus that the ocean and atmosphere did not become oxygenated to near-modern levels until the mid-Paleozoic, coinciding with the onset of generally lower extinction rates. Physiological theory provides us with a possible causal link between these two observations-predicting that the synergistic impacts of oxygen and temperature on aerobic respiration would have made marine animals more vulnerable to ocean warming events during periods of limited surface oxygenation. Here, we evaluate the hypothesis that chang…
An update of the known distribution and status of Cherax spp. in Italy (Crustacea, Parastacidae)
2022
To date, only two Cherax species have been reported to occur in Italy, i.e., C. destructor Clark, 1936 and C. quadricarinatus (von Martens, 1868), both in the wild and in aquaculture farms. Therefore, we aimed to update their current status and distribution in Italian mainland and Sicily. In addition, we investigated the origin of their known populations, and their possible routes of invasion. In order to genetically characterize the Cherax populations occurring in Italian inland waters and aquaculture facilities, the barcode region of the mtDNA gene cytochrome oxidase subunit I was sequenced in the available specimens originating from an aquaculture facility and a museum collection. The sa…
Genética de la conservación: la aplicación de los conceptos de la evolución a la conservación de la diversidad biológica
2013
La comprensión de las fuerzas de cambio evolutivo que actúan sobre las poblaciones, en conjunción con las técnicas más modernas de análisis genético, lleva aplicándose en los últimos veinte años al servicio de la conservación de la biodiversidad. Esta nueva aplicación de la genética ha recibido el nombre de genética de la conservación.
Risk of Local Extinction of Odonata Freshwater Habitat Generalists and Specialists
2014
Understanding the risk of a local extinction in a single population relative to the habitat requirements of a species is important in both theoretical and applied ecology. Local extinction risk depends on several factors, such as habitat requirements, range size of species, and habitat quality. We studied the local extinctions among 31 dragonfly and damselfly species from 1930 to 1975 and from 1995 to 2003 in Central Finland. We tested whether habitat specialists had a higher local extinction rate than generalist species. Approximately 30% of the local dragonfly and damselfly populations were extirpated during the 2 study periods. The size of the geographical range of the species was negati…
Habitat fragmentation compromises the population dynamic of the globally near-threatened Straight-billed Reedhaunter (Limnoctites rectirostris)
2018
AbstractUnderstanding the consequences of habitat fragmentation to biological populations is crucial to develop sound conservation polices. The Straight-billed Reedhaunter (Limnoctites rectirostris) is a little known and threatened Passeriform that is highly dependent Erygo wetlands patches. Here, we evaluated the effects of habitat fragmentation on populations of the Straight-billed Reedhaunter, during the construction of a water reservoir in southern Brazil. During eight months, we monitored five Eryngo wetlands patches occupied (n=3) and no occupied (n=2) by Straight-billed Reedhaunter individuals, collecting data on their temporal occupancy patterns and registering new fragmentation eve…
Effects of fragmented breeding habitat and resource distribution on behavior and survival of the bank vole ( Myodes glareolus )
2010
Habitat fragmentation causes negative population trends or even local extinction in many species. Understanding the role of fragmentation on behavior and space use of animals is an essential part of revealing the mechanism behind observed population declines. We studied experimentally the effects of small-scale habitat fragmentation on the distribution and movement of bank voles (Myodes glareolus) in seminatural enclosures. We predicted that besides habitat structure, availability of two resources, food for both sexes, and receptive females for males, determine individual distribution. We manipulated female density (either 0, 4, or 12 per enclosure) and followed movements of radio-collared …
Origination and extinction patterns of mammals in three central Western Mediterranean islands from the Late Miocene to Quaternary
2008
Abstract An overview of the population histories of three insular realms (Gargano palaeo-archipelago, Sardinia–Maritime Tuscany palaeo-bioprovince and the Sicilian insular complex) during the Late Miocene and Quaternary are here presented. The complexity of biodiversity changes in the islands is analysed to propose an interpretation of origination and extinction patterns. The study highlighted several important aspects of insular faunas. Evolutionary radiations were found to contribute significantly only to the Gargano faunal diversity, likely because the area was an archipelago at the time. Another interesting result is that large and small mammals do not disperse and become extinct all at…
End-Triassic Extinction in a Carbonate Platform From Western Tethys: A Comparison Between Extinction Trends and Geochemical Variations
2022
The Triassic/Jurassic boundary section cropping out at Mt Sparagio in north-western Sicily (Italy) consists of a thick and continuous peritidal succession typical of a Tethyan carbonate platform. The combined chemostratigraphic and biostratigraphic study of this section allowed us to parallel the environmental variations inferred by the isotopic records and the extinction trends recorded by the benthic organisms. In the studied section, the isotope data of C, O, and S are indicative of serious environmental perturbations related to the Central Atlantic Magmatic Province (CAMP) activity, as recorded worldwide. Two negative excursions in the C-curve (Initial-CIE and Main-CIE) confirm the acid…
Functional structure of European forest beetle communities is enhanced by rare species
2022
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, roles of individual species are poorly known. Rare species, often most likely to go extinct, may have unique traits and 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 captures of wood-living (saproxylic) beetle species, combined with recent databases of morphological and ecological traits, from three regions in central and northern Europe. Using a rarity index based…