Search results for "Extinction"
showing 10 items of 458 documents
Cautionnement. Conditions de la décharge d'une caution. Fait du créancier susceptible de rendre la subrogation impossible. Effet légal de purge des i…
2014
International audience; (Rouen, ch. proximité, 30 mai 2013, n° 12/03264, M. Gilbert Sicsic c/ SA BNP Paribas, JurisData n° 2013-015920)
Climate change reshuffles northern species within their niches
2022
Climate change is a pervasive threat to biodiversity. While range shifts are a known consequence of climate warming contributing to regional community change, less is known about how species' positions shift within their climatic niches. Furthermore, whether the relative importance of different climatic variables prompting such shifts varies with changing climate remains unclear. Here we analysed four decades of data for 1,478 species of birds, mammals, butterflies, moths, plants and phytoplankton along a 1,200 km high latitudinal gradient. The relative importance of climatic drivers varied non-uniformly with progressing climate change. While species turnover among decades was limited, the …
Plant facilitation and phylogenetics
2013
The relationship between facilitation and evolutionary ecology is poorly understood. We review five issues elucidating how the phylogenetic relatedness of species provides insight into the role of facilitation in community assembly: (a) Are the facilitative interactions more common between species that differ in a regeneration niche? (b) Are facilitative interactions more common between distantly related species? (c) Do communities governed by facilitation (rather than competition) have higher phylogenetic diversity? (d) As facilitated juvenile plants mature, do they compete with their nurses more often if they are closely related to them? (e) How does the phylogenetic signature in a commun…
Context specificity of both acquisition and extinction of a Pavlovian conditioned response
2016
It is widely held that the extinction of a conditioned response is more context specific than its initial acquisition. One proposed explanation is that context serves to disambiguate the meaning of a stimulus. Using a procedure that equated the learning histories of the contexts, we show that the memory of an appetitive Pavlovian association can be highly context specific despite being unambiguous. This result is inconsistent with predictions of the Rescorla–Wagner model of learning but in line with configural accounts of contextual control of behavior. We propose an explanatory model in which context serves to modulate the gain of associative strength and which expands upon the configural …
Blocking NMDA-receptors in the pigeon's "prefrontal" caudal nidopallium impairs appetitive extinction learning in a sign-tracking paradigm
2015
Extinction learning provides the ability to flexibly adapt to new contingencies by learning to inhibit previously acquired associations in a context-dependent manner. The neural networks underlying extinction learning were mostly studied in rodents using fear extinction paradigms. To uncover invariant properties of the neural basis of extinction learning, we employ pigeons as a model system. Since the prefrontal cortex of mammals is a key structure for extinction learning, we assessed the role of N-methyl-D-aspartate receptors (NMDARs) in the nidopallium caudolaterale, the avian functional equivalent of mammalian prefrontal cortex. Since NMDARs in prefrontal cortex have been shown to be rel…
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…
Organochlorine Pesticides and Polychlorinated Biphenyl Congeners in LannerFalco biarmicus feldeggiiSchlegel Chicks and Lanner Prey in Sicily, Italy
2008
This paper reports on research conducted to elucidate the risk posed to the Sicilian population of the endangered lanner falcon Falco biarmicus feldeggii Schlegel by organochlorine (OC) pesticides and polychlorinated biphenyls (PCBs), as part of a wider study on contaminant risk to the lanner. Seventeen lanner nest sites were studied in northern and central Sicily. Sampling (in 2005) and analysis were carried out for selected OC pesticides and PCB congeners in lanner chick blood (15 chicks from 6 nest sites) and in two of the main lanner prey species, magpie Pica pica (36 individuals from 6 lanner nest sites) and rock dove Columba livia (10 individuals from 2 lanner nest sites). No OC and P…
Buffer strips can pre-empt extinction debt in boreal streamside habitats
2013
Background Conservation of biological diversity and economical utilization of natural resources form an almost inevitable confrontation between the two. In practice, however, a balance between the two ought to be found, and in managed boreal forests, preservation of woodland key habitats is increasingly used strategy to safeguard biological diversity. According to the Finnish Forests Act, certain Forest Act habitat (FAH) types must be safeguarded, provided they are clearly distinguishable from their surroundings. Furthermore, once the habitat has been identified as a FAH, its special characteristics must not be altered. Both of these aspects contain ambiguities that potentially undermine th…
Predicting the risk of extinction from shared ecological characteristics
2005
Understanding the ultimate causes of population declines and extinction is vital in our quest to stop the currently rampant biodiversity loss. Comparison of ecological characteristics between threatened and nonthreatened species may reveal these ultimate causes. Here, we report an analysis of ecological characteristics of 23 threatened and 72 nonthreatened butterfly species. Our analysis reveals that threatened butterflies are characterized by narrow niche breadth, restricted resource distribution, poor dispersal ability, and short flight period. Based on the characteristics, we constructed an ecological extinction risk rank and predicted which of the currently nonthreatened species are at …
Plasmon de surface de particules métalliques toroïdales
2006
This thesis deals with the optical properties of small metal torii. A method of resolution of the equation of Laplace in toroidal coordinates is introduced and the radiative properties of the metal toric nanoparticules are studied within the electrostatic framework. The study on the eigenmodes spatial distribution suggests that metal nanotorus can carry a non-zero magnetic dipole moment at optical frequencies. Analytical expressions for the extinction and scattering cross sections of the torus are also found and compared with numerical simulations and experimental results obtained with collaborations. The sensitivity of the plasmon frequency to the refraction index of the external medium an…