Literatura académica sobre el tema "Traités – Extinction"
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Artículos de revistas sobre el tema "Traités – Extinction"
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Napoleon, Val. "Extinction by Number: Colonialism Made Easy". Canadian journal of law and society 16, n.º 1 (abril de 2001): 113–45. http://dx.doi.org/10.1017/s0829320100006608.
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RésuméL'existence en tant que nation peut être définie positivement, ce qui amènera un modèle civique de citoyenneté, ou négativement, par un modèle ethnique de citoyenneté. Chaque approche a un effet direct et formatif sur le pouvoir politique de la nation et ses relations nationales et internationales. Le modèle ethnique de définir les Premières Nations, introduit par les gouvernements coloniaux par voie législative et par traités ensuite et qui est adopté par les Premières Nations, rend leur pouvoir politique diffus et dénature leurs enjeux nationaux, en les délimitant essentiellement aux désavantages sociaux et économiques. Un modèle civique inclusif de la nation, par contre, permettra aux Premières Nations de rebâtir et de maintenir leur pouvoir et intégrité politiques en avançant au-delà de l'établissement de leurs frontières et de leur identité interne fondée sur le sang et l'appartenance ethnique. Les débats politiques et juridiques contemporains sur l'autonomie, les droits et titres autochtones et les traités partent surtout de conceptions occidentales de la nation, sur fond d'histoire et de cultures européennes. Les conceptions des Premières Nations demeurent peu articulées ou obscurcies, si elles ne sont pas mises de côté aux tables de négociation sur l'autonomie et les traités, au détriment des Premières Nations. La conséquence de cette approche est de renforcer le déséquilibre structural du pouvoir, plutôt que d'encourager un changement politique, économique et social positif pour les Premières Nations. Une approche différente s'impose. Les conceptions occidentales et autochtones de la nation et de la citoyenneté doivent être analysées et comparées de manière critique. Les Premières Nations doivent commencer à rebâtir des sociétés inclusives, civiques et viables fondées sur des nations plutôt que sur la notion inefficace des bandes empruntée à la Loi sur les Indiens.
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McKinney, Michael L. "Extinction selectivity among lower taxa: gradational patterns and rarefaction error in extinction estimates". Paleobiology 21, n.º 3 (1995): 300–313. http://dx.doi.org/10.1017/s0094837300013312.
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Documenting past environmental disturbances will provide a very incomplete explanation of extinctions until more data on intrinsic (e.g., phylogenetic) responses to disturbances are collected. Taxonomic selectivity can be used to infer phylogenetic inheritance of extinction-biasing traits. Selectivity patterns among higher taxa, such as between mammals and bivalves, are well documented. Selectivity patterns among lower taxa (genus, species) have great potential for understanding the dynamics underlying higher taxic turnover. Two echinoid data sets, of fossil and living taxa, indicate that species extinctions do not occur randomly within genera. Reverse rarefaction estimates of past species extinction rates assume random species extinction within higher taxa, so these widely cited extinction estimates may be inaccurate. Revised estimates based on a simulated curve imply that past species extinctions rates may be 6%–15% lower than previously cited. Possible causes for the observed selectivity patterns are discussed. These include nonrandom phylogenetic nesting of species with traits often cited as enhancing extinction vulnerability, into certain taxa. Such traits include low abundance, large body size, narrow niche breadth, and many others. Phylogenetic nesting of extinction-biasing traits at many taxonomic levels does not predict that a dichotomy of mass-background selectivity based on a few traits will occur. Instead, it predicts patterns of selectivity at many taxonomic levels, and at many spatio-temporal scales.
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Gray, Alan. "The ecology of plant extinction: rates, traits and island comparisons". Oryx 53, n.º 3 (21 de mayo de 2018): 424–28. http://dx.doi.org/10.1017/s0030605318000315.
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AbstractAlthough there is increasing evidence for a sixth mass extinction, relatively few plants have been officially declared extinct (<150 are categorized as Extinct on the IUCN Red List). The Red List, although the data are neither perfect nor comprehensive, is perhaps the most reliable indicator of extinction and extinction threat. Here, data collated from the Red List, of Extinct plant species and of Critically Endangered plant species with populations in decline, are examined to address three questions: (1) How do background, continental, and island plant extinction rates compare? (2) Are biological and physical island parameters associated with plant extinction? (3) Are any plant traits associated with extinction and if so do these differ between islands and continents? The background rate for plant extinction is estimated to be 0.05–0.13 E/MSY (extinctions per million species-years) and the Red List data are above these background rates and also above a higher extinction rate of 0.15 E/MSY. The data indicate that plant extinctions are dominated by insular species. The Red List extinction data are associated with lower competitive ability and lower climate change velocities, and anthropogenic factors. Analyses using only Critically Endangered species whose populations are in decline (arguably the species most at risk of extinction in the near future) largely mirrors this pattern and suggests that drivers of plant extinction may have an inertia that could last well into the future.
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Lyons, S. Kathleen, Joshua H. Miller, Danielle Fraser, Felisa A. Smith, Alison Boyer, Emily Lindsey y Alexis M. Mychajliw. "The changing role of mammal life histories in Late Quaternary extinction vulnerability on continents and islands". Biology Letters 12, n.º 6 (junio de 2016): 20160342. http://dx.doi.org/10.1098/rsbl.2016.0342.
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Understanding extinction drivers in a human-dominated world is necessary to preserve biodiversity. We provide an overview of Quaternary extinctions and compare mammalian extinction events on continents and islands after human arrival in system-specific prehistoric and historic contexts. We highlight the role of body size and life-history traits in these extinctions. We find a significant size-bias except for extinctions on small islands in historic times. Using phylogenetic regression and classification trees, we find that while life-history traits are poor predictors of historic extinctions, those associated with difficulty in responding quickly to perturbations, such as small litter size, are good predictors of prehistoric extinctions. Our results are consistent with the idea that prehistoric and historic extinctions form a single continuing event with the same likely primary driver, humans, but the diversity of impacts and affected faunas is much greater in historic extinctions.
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Green, Walton A., Gene Hunt, Scott L. Wing y William A. DiMichele. "Does extinction wield an axe or pruning shears? How interactions between phylogeny and ecology affect patterns of extinction". Paleobiology 37, n.º 1 (2011): 72–91. http://dx.doi.org/10.1666/09078.1.
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Extinctions are caused by environmental and ecological change but are recognized and measured in the fossil record by the disappearance of clades or lineages. If the ecological preferences of lineages or taxa are weakly congruent with their phylogenetic relationships, even large ecological perturbations are unlikely to drive major clades extinct because the factors that eliminate some species are unlikely to affect close relatives with different ecological preferences. In contrast, if phylogenetic relatedness and ecological preferences are congruent, then ecological perturbations can more easily cause extinctions of large clades. In order to quantify this effect, we used a computer model to simulate the diversification and extinction of clades based on ecological criteria. By varying the parameters of the model, we explored (1) the relationship between the extinction probability for a clade of a given size (number of terminals) and the overall intensity of extinction (the proportion of the terminals that go extinct), and (2) the congruence between ecological traits of the terminals and their phylogenetic relationships. Data from two extinctions (planktonic foraminifera at the Eocene/Oligocene boundary and vascular land plants at the Middle/Late Pennsylvanian boundary) show phylogenetic clustering of both ecological traits and extinction probability and demonstrate the interaction of these factors. The disappearance of large clades is observed in the fossil record, but our model suggests that it is very improbable without both high overall extinction intensities and high congruence between ecology and phylogeny.
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Janevski, G. Alex y Tomasz K. Baumiller. "Evidence for extinction selectivity throughout the marine invertebrate fossil record". Paleobiology 35, n.º 4 (2009): 553–64. http://dx.doi.org/10.1666/0094-8373-35.4.553.
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The fossil record has been used to show that in some geologic intervals certain traits of taxa may increase their survivability, and therefore that the risk of extinction is not randomly distributed among taxa. It has also been suggested that traits that buffer against extinction in background times do not confer the same resistance during mass extinction events. An open question is whether at any time in geologic history extinction probabilities were randomly distributed among taxa. Here we use a method for detecting random extinction to demonstrate that during both background and mass extinction times, extinction of marine invertebrate genera has been nonrandom with respect to species richness categories of genera. A possible cause for this nonrandom extinction is selective clustering of extinctions in genera consisting of species which possess extinction-biasing traits. Other potential causes considered here include geographic selectivity, increased extinction susceptibility for species in species-rich genera, or biases related to taxonomic practice and/or sampling heterogeneity. An important theoretical result is that extinction selectivity at the species level cannot be smoothly extrapolated upward to genera; the appearance of random genus extinction with respect to species richness of genera results when extinction has been highly selective at the species level.
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Smits, Peter D. "Expected time-invariant effects of biological traits on mammal species duration". Proceedings of the National Academy of Sciences 112, n.º 42 (5 de octubre de 2015): 13015–20. http://dx.doi.org/10.1073/pnas.1510482112.
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Determining which biological traits influence differences in extinction risk is vital for understanding the differential diversification of life and for making predictions about species’ vulnerability to anthropogenic impacts. Here I present a hierarchical Bayesian survival model of North American Cenozoic mammal species durations in relation to species-level ecological factors, time of origination, and phylogenetic relationships. I find support for the survival of the unspecialized as a time-invariant generalization of trait-based extinction risk. Furthermore, I find that phylogenetic and temporal effects are both substantial factors associated with differences in species durations. Finally, I find that the estimated effects of these factors are partially incongruous with how these factors are correlated with extinction risk of the extant species. These findings parallel previous observations that background extinction is a poor predictor of mass extinction events and suggest that attention should be focused on mass extinctions to gain insight into modern species loss.
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Collen, Ben, Louise McRae, Stefanie Deinet, Adriana De Palma, Tharsila Carranza, Natalie Cooper, Jonathan Loh y Jonathan E. M. Baillie. "Predicting how populations decline to extinction". Philosophical Transactions of the Royal Society B: Biological Sciences 366, n.º 1577 (12 de septiembre de 2011): 2577–86. http://dx.doi.org/10.1098/rstb.2011.0015.
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Global species extinction typically represents the endpoint in a long sequence of population declines and local extinctions. In comparative studies of extinction risk of contemporary mammalian species, there appear to be some universal traits that may predispose taxa to an elevated risk of extinction. In local population-level studies, there are limited insights into the process of population decline and extinction. Moreover, there is still little appreciation of how local processes scale up to global patterns. Advancing the understanding of factors which predispose populations to rapid declines will benefit proactive conservation and may allow us to target at-risk populations as well as at-risk species. Here, we take mammalian population trend data from the largest repository of population abundance trends, and combine it with the PanTHERIA database on mammal traits to answer the question: what factors can be used to predict decline in mammalian abundance? We find in general that environmental variables are better determinants of cross-species population-level decline than intrinsic biological traits. For effective conservation, we must not only describe which species are at risk and why, but also prescribe ways to counteract this.
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Bascompte, Jordi, María B. García, Raúl Ortega, Enrico L. Rezende y Samuel Pironon. "Mutualistic interactions reshuffle the effects of climate change on plants across the tree of life". Science Advances 5, n.º 5 (mayo de 2019): eaav2539. http://dx.doi.org/10.1126/sciadv.aav2539.
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Climatically induced local species extinctions may trigger coextinction cascades, thus driving many more species to extinction than originally predicted by species distribution models. Using seven pollination networks across Europe that include the phylogeny and life history traits of plants, we show a substantial variability across networks in climatically predicted plant extinction—and particularly the subsequent coextinction—rates, with much higher values in Mediterranean than Eurosiberian networks. While geographic location best predicts the probability of a plant species to be driven to extinction by climate change, subsequent coextinctions are best predicted by the local network of interactions. These coextinctions not only increase the total number of plant species being driven to extinction but also add a bias in the way the major taxonomic and functional groups are pruned.
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Forero-Medina, German, Marcus Vinícius Vieira, Carlos Eduardo de Viveiros Grelle y Paulo Jose Almeida. "Body size and extinction risk in Brazilian carnivores". Biota Neotropica 9, n.º 2 (junio de 2009): 45–49. http://dx.doi.org/10.1590/s1676-06032009000200004.
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Because extinctions are not random across taxa, it is important for conservation biologists to identify the traits that make some species more vulnerable. Factors associated with vulnerability include small geographical ranges, low densities, high trophic level, "slow" life histories, body size, and tolerance to altered habitats. In this study we examined the relationship of body size, reproductive output, longevity, and extinction risk for carnivores occurring in Brazil. We used generalized linear models analyses on phylogenetically independent contrasts to test the effect of body size alone, and the combined effect of body size, litter size and longevity on extinction risk. Body size appeared in the two best models according to the selection criteria (AIC), and it was the most plausible bionomic variable associated with extinction risk. Litter size and longevity, bionomic traits previously associated with threat risk of Brazilian carnivores, were implausible. The higher extinction risk for larger species could result from body size influencing vulnerability to different human activities, such as killing, habitat destruction and fragmentation, and the small size of natural reserves.
Tesis sobre el tema "Traités – Extinction"
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Clarenc, Nathalie. "La suspension des engagements internationaux". Thesis, Paris 2, 2015. http://www.theses.fr/2015PA020057.
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Il s’agit d’une étude de droit des actes juridiques internationaux (engagements conventionnels et unilatéraux), portant sur un mécanisme largement utilisé dans la pratique conventionnelle mais très peu étudié en doctrine, celui de la suspension, distingué des mécanismes, plus radicaux mais finalement moins intéressants peut-être, d’extinction des engagements. Pour la première fois, est proposée une définition de la suspension, préalablement distinguée des notions voisines avec lesquelles elle a souvent été confondue (dispense, exception d’inexécution, force majeure, contre-mesures, réserve, etc… et surtout, dénonciation et retrait). La définition proposée fait état des caractéristiques de la suspension telle qu’elle se donne à voir dans les clauses conventionnelles, la pratique diplomatique et la jurisprudence, et prend appui sur la « théorie de l’engagement ». L’étude vise également à clarifier le régime de la suspension, duquel Fitzmaurice disait qu’il soulevait de « graves difficultés de classification et de plan ». L’examen de la pratique révèle en effet que ce régime n’est pas unique mais dual, originalité qui ne manquera pas de frapper la curiosité du lecteur, et dont la mise à jour permet une meilleure compréhension du phénomène de suspensionThis study focuses on a mechanism frequently used in legal practice, but, surprisingly, often ignored in international doctrine: suspension. The mechanism of suspension is to be distinguished from more radical, but arguably less interesting mechanisms, such as revocation. Suspension will be analysed within the context of both conventional and unilateral international law commitments. For the first time, a general definition of suspension will be proposed, which sets it apart from the many similar notions with which it has been confused, such as dispense, exception of inexecution, force majeure, countermeasures, reservations, …, and last but not least, denunciation and withdrawal. The proposed definition also aims to identify characteristics that are unique to suspension, as shown in treaty clauses, in diplomatic practice and case law, and as supported by « commitment theory ». The study will also clarify the legal regime of suspension, which, according to Fitzmaurice, involves « serious difficulties of classification and content ». Indeed, a closer look at suspension in practical terms reveals that there are not one, but two legal regimes of suspension. This eye-opening conclusion will not fail to engage the reader’s interest and will contribute to our further understanding of the phenomenon of suspension
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Ayman, Randi. "La dénonciation et la renégociation des traités". Electronic Thesis or Diss., Paris 1, 2020. http://www.theses.fr/2020PA01D017.
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La dénonciation et la renégociation sont deux notions qui ne partagent pas de traits caractéristiques communs. L’une est un acte unilatéral qui met fin à la participation d’un Etat à un traité, tandis que l’autre consiste à mener un dialogue entre les Etats parties à un traité en vue de maintenir le lien conventionnel tout en lui apportant des changements substantiels. Cependant, les Etats ont souvent recours à la dénonciation et à la renégociation d’un traité comme solution alternative pour un même motif, à savoir un changement de circonstances. Ce constat a suscité notre intérêt d’étudier l’articulation de la dénonciation et la renégociation lorsqu’elles portent sur un même traité, notamment quand elles sont invoquées simultanément. Cette thèse soutient l’omniprésence d’une possibilité de renégocier le traité dans tous les cas de dénonciation. Toutefois, la renégociation peut ne jamais se manifester, compte tenu notamment du traité en question et des circonstances entourant la dénonciation de celui-ci. Il s’agirait dans un tel cas d’une possibilité dormante. Nous soutenons également que la renégociation n’opère qu’avant la prise d’effet de la dénonciation. L’étude du régime juridique et des effets de ces deux notions démontre que la dénonciation et la renégociation sont en effet procéduralement liées. Elles obéissent ainsi à certaines conditions communes et sont gouvernées par des principes communs. Par ailleurs, bien que leurs effets soient a priori opposés, ceux-ci s’entrelacent à plusieurs égards. Enfin, il ressort de cette étude que la dénonciation et la renégociation des traités jouent un rôle pivot dans l’atténuation de la tension entre les exigences de stabilité juridique et de mutation sociale. Elles sont des outils d’adaptation, et de ce fait, constituent des éléments de flexibilité du traité permettant de gérer les risques liés à l’évolution de la société en offrant un moyen de réaménager le traité ou de s’en libérer, selon les circonstancesDenunciation and renegotiation are two notions that do not share common features. One is a unilateral act that terminates a State’s participation in a treaty, whereas the other is a dialogue between States parties to a treaty aiming to maintain the conventional relationship while making substantial changes to it. Nonetheless, States often resort to the denunciation and the renegotiation of a treaty as an alternative solution for the same reason, namely a change of circumstances. This observation aroused our interest in studying the interaction between denunciation and renegotiation when they relate to the same treaty, in particular when they are invoked simultaneously. This thesis supports the omnipresence of the possibility of renegotiating the treaty in all cases of denunciation. However, a renegotiation may never occur, particularly in view of the treaty in question and the circumstances surrounding its denunciation. In such a case, it would be a dormant possibility. We also argue that renegotiation only takes place before the denunciation takes effect. A study of the legal regime and the effects of these two concepts shows that denunciation and renegotiation are in fact procedurally linked. They thus obey certain common conditions and are governed by common principles. Moreover, although their effects are seemingly divergent, these are intertwined in several respects. Finally, this study shows that denunciation and renegotiation of treaties play a pivotal role in reducing the tension between the requirements of legal stability and social change. They are tools for adaptation, and thus constitute elements of treaty flexibility that allow to manage the risks associated with social change by providing a means of rearranging the treaty or to break away from it, depending on the circumstances
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Kemp, Lindsay. "The Relationship Between Extinction Learning Processes and Callous Unemotional Traits". Thesis, The University of Sydney, 2022. https://hdl.handle.net/2123/28875.
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Callous Unemotional (CU) traits are an informative clinical construct, identifying individuals at risk of conduct disorder and treatment resistance. This thesis examines associative processes that may underlie this resistance. Specifically, extinction learning processes, which allow individuals to maintain expectations that match the outcomes of their behaviour. It is often assumed that there is an established link between CU traits and deficient associative learning of this kind. However, a systematic review of the current literature, described in this thesis, reveals that the evidence for this relationship is not consistent. This finding indicated the need for a study of this correlation using a well powered experimental methodology. As a result, six studies were carried out to develop a computer-based task able to measure extinction learning in large samples from the general population, with CU traits assessed using the Inventory of Callous Unemotional Traits (ICU). Findings from this series included repeated observations of CU trait associated extinction deficits. They also provided unique data on whether CU traits affect the relapse of extinguished behaviour. Furthermore, an unanticipated effect of cultural factors was observed. In consideration of these findings, observed parameters were utilised in the design of a large-scale confirmatory study with over 700 participants. This study also investigated the role of cultural variables in the structure and external validity of the ICU, as well as its association with extinction learning. This thesis therefore provides useful data on the relationship between CU traits and extinction learning, as well as on the cross- cultural validity of the ICU, representing a significant contribution to our understanding of the aetiology and phenotypic characteristics of CU traits.
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White, Rachel Louise. "Global biogeography of traits and extinction risk in birds : an elevational perspective". Thesis, University of Kent, 2013. https://kar.kent.ac.uk/48195/.
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Mountains are hotspots of terrestrial species richness and endemism, but the reasons why are poorly understood. Extensive reviews of the literature, across taxa, reveal that research on trait and extinction risk variation with respect to elevational distribution are outnumbered by studies on latitudinal gradients and geographical range size, and are taxonomically and geographically restricted. The aim of this thesis is to analyse interspecific variation in morphology, life history, ecology, and extinction risk with respect to elevational distribution – at the global scale and across a broad taxonomic range. To achieve this, I use birds as a model system, a global avian trait database and a comparative approach – employing both bivariate and multivariate statistical techniques. Elevational distribution is shown to be positively associated with reproduction and niche breadth, whilst being negatively associated with morphology, growth and survival – even when controlling for body weight, geographical range, and latitude. Birds with larger elevational ranges and higher maximum and midpoint elevations possess traits consistent with a fast life history, and vice versa. Fast life histories at high elevations may result from exposure to more variable/seasonal environments compared to lowland birds. Global avian extinction risk is found to be greatest in lowland species and those with small elevational ranges. Overall, these relationships remained robust at the family level, for species within biogeographic realms, endemic subsets, and across phylogenetically independent contrasts. This research will add to current understanding of large-scale ecology, trait biogeography, and conservation biology – assisting the incorporation of an elevational perspective into biogeography and macroecology theory, and conservation practice. Future work should focus on further identifying the underlying processes for the patterns shown here, and investigating their generality across other vertebrate groups, e.g. mammals.
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Golding, Janice Sarah. "Herbarium-based Trait Studies on Plant Extinction Risk in the Flora Zambesiaca Region, South-Central Africa". Thesis, University of Oxford, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.517144.
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Granberg, Åsa. "Microbotryum violaceum on Silene dioica : understanding traits that influence plant-pathogen interactions". Doctoral thesis, Umeå universitet, Ekologi, miljö och geovetenskap, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-1387.
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The dynamics of a plant-pathogen interaction vary both within and among species. Both spatial structuring and specific genetic and life-history characteristics will affect the interaction and the outcome of a potential co-evolution between the two organisms. In this thesis I have studied the interaction between the wild perennial herb Silene dioica and its automictic, obligate anther smut Microbotryum violaceum MvSd. From the plant perspective, I have examined different aspects of biochemical resistance in S. dioica to M. violaceum MvSd. From the pathogen perspective, I have focused on the breeding system of M. violaceum MvSd and its connection to fitness and distribution of genetic diversity. I have used varying methods; glasshouse trails involving inoculation of plants with the pathogen, classical Mendelian analysis involving controlled crosses between plants, microscopic studies of spores and molecular DNA-analysis. With the results I demonstrate that resistance to M. violaceum MvSd in S. dioica can be specific to the attacking pathogen strain and also spatially highly diverse both within and among populations within a metapopulation. Together, these factors are likely to delay the establishment of the disease within host populations and reduce the spread and amount of disease, once it has been established. The results also suggest that the specific resistance expressed against two different M. violaceum MvSd strains were determined by separate gene systems and that, in both cases, the resistance was simply inherited. This implies a potential for relatively rapid response to M. violaceum-induced selection in S. dioica populations variable for resistance. My results also show that automixis clearly is the predominating breeding system of M. violaceum MvSd, similarly to what earlier has been shown for M. violaceum MvSl. Furthermore, I found lower levels of neutral genetic diversity in M. violaceum MvSd in the northern parts of Sweden, compared to what has been found in populations in more southern Europe. This result is consistent with predictions that populations in the outer regions of a species distribution have lower levels of genetic variation. Moreover, populations were highly differentiated in northern Sweden, which could have been generated by high selfing rates, genetic drift and high population turnover rates, all factors that coincide with life-history and ecology of M. violaceum MvSd. However, despite the general low variability in neutral genetic markers, I did find variation in fitness related traits, both within and among populations, as well as differences in infection ability between strains, suggesting there is a potential for co-evolution between S. dioica and M. violaceum MvSd in the area. To summarize, this thesis reflect a plant-pathogen system that is highly influenced by constant colonisation-extinction dynamics, which is likely to have influenced both the genetics of resistance in the plant and the breeding system of the pathogen and thus also the interaction between the two organisms.
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Burst, Maxime. "Les communautés végétales des interfaces forêt-prairie et leur environnement face aux cas d'afforestation et de déforestation". Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0078/document.
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En Europe tempérée, les paysages sont dominés par une mosaïque de forêts, prairies et cultures depuis plusieurs siècles. Cette longue période de temps a permis la spécialisation d'espèces au sein des habitats et de leurs interfaces grâce à de forts contrastes environnementaux. Cependant, de fréquents changements d'occupation du sol ont eu lieu par le passé, lesquels se sont accélérés dans les dernières décennies, remettant en cause la stabilité des communautés végétales et de leur environnement. L'afforestation d'anciennes prairies et l'extension de prairies par déforestation, le plus souvent issues de la progression et de la régression d'anciennes lisières, n'ont que peu été étudiées. Au sein des interfaces foret-prairie, en plus d'un effet lisière induit au sein de chaque habitat par la proximité de l'habitat adjacent, un effet histoire peut s'ajouter au sein des habitats récents, c'est-à-dire un héritage environnemental et/ou floristique (dette d'extinction, crédit de colonisation). Au sein des lisières d'habitats récents, une interaction entre effet lisière et effet histoire peut également être rencontrée. Dans cette thèse, les objectifs ont été d'évaluer l'influence relative de l'effet lisière et de l'effet histoire le long d'interfaces forêt-prairie stables, issues d'afforestation et issues de déforestation en s'intéressant (i) aux conditions environnementales, (ii) à la richesse et à la composition floristique des communautés végétales, et (iii) aux valeurs de traits au sein des communautés. Nos résultats ont montré des gradients croissants d'intensité lumineuse et de nutriments des sols allant des lisières aux cœurs de prairies. En réponse à ces gradients, un fort effet lisière sur la composition des communautés végétales a été trouvé en prairie. Ces différences floristiques entre lisières et cœurs de prairies s'expliquent par la présence d'un grand nombre d'espèces transgressives parmi les espèces spécialistes de forêt, lesquelles ont des valeurs de traits favorisant leur transgression en prairie. A côté de cela, une dette d'extinction d'espèces spécialistes de prairie a été trouvée au sein des forêts récentes, laquelle est responsable d'une hauteur végétative plus importante par rapport aux forêts anciennes. Ces résultats s'expliquent par une intensité lumineuse restée plus élevée au sein des forêts récentes, même après plusieurs décennies. Une dette d'extinction d'espèces spécialistes de forêt a aussi été mise en évidence en lisière de prairie récente, laquelle est le résultat d'une interaction entre effet lisière et effet histoire. En prairie récente, l'effet lisière favorise le maintien des espèces forestières. D'après nos résultats, les lisières de forêt et de prairie, dont la plupart ont subit un déplacement au cours des deux derniers siècles, hébergent de nombreuses espèces végétales spécialistes des habitats anciens, parfois en dette d'extinction. Une réévaluation de la distribution des espèces au sein des communautés végétales de forêts et prairies semble alors nécessaire en tenant en compte de l'histoire des habitats. Face à l'instabilité croissante des forêts et prairies, l'identification des espèces en dette d'extinction représente une chance pour la conservation et la restauration de la biodiversité végétaleIn temperate Europe, landscapes are dominated by a mosaic of forests, grasslands and crops since several centuries. This long period of time allowed the specialization of species within the habitats and their interfaces thanks to strong environmental contrasts. However, there have been frequent land-use changes in the past, which have accelerated in recent decades, challenging the stability of plant communities and their environment. The afforestation of former grasslands and the extension of grasslands by deforestation, mostly resulting from the progression and regression of the edges, have been poorly studied. In the forest-grassland interfaces, in addition to an edge effect induced in each habitat by the proximity to the adjacent habitat, a history effect can be added in recent habitats, i.e. an environmental and/or floristic legacy (extinction debt, colonization credit). In the recent habitat edges, an interaction between edge effect and history effect can also be encountered. In this thesis, the objectives were to evaluate the relative abundance of the edge effect and the history effect along forest-grassland interfaces stable, from afforestation process and from deforestation process, by studying (i) environmental conditions, (ii) the richness and floristic composition of plant communities, and (iii) trait values within communities. Our results showed increasing gradients of light intensity and soil nutrients ranging from grassland edges to grassland cores. In response to these gradients, a strong edge effect on the composition of plant communities was found in grasslands. These floristic differences between grassland edges and grassland cores are explained by the presence of a large number of transgressive species among the forest specialist species, which have trait values favoring their transgression in grasslands. Besides this, an extinction debt of grassland specialist species has been found in recent forests, which is responsible for a higher vegetative height compared to ancient forests. These results can be explained by the fact that light intensity remained higher in recent forests, even after several decades. An extinction debt of forest specialist species has also been demonstrated in the recent grassland edges, which is the result of an interaction between edge effect and history effect. In recent grasslands, the edge effect favors the maintenance of forest species. According to our findings, forest and grassland edges, most of which have been displaced over the past two centuries, are home to many plant species that are habitat specialists, sometimes in extinction debt. A re-evaluation of the distribution of species within forest and grassland plant communities then seems necessary, taking into account the history of habitats. In a context of increasing forests and grasslands instability, the identification of species in extinction debt represents an opportunity for the conservation and restoration of plant biodiversity
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Comont, Richard Francis. "Modelling the impact of an alien invasion : Harmonia axyridis in Britain". Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:08de972b-1c12-4862-bb7d-95d614a9e011.
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Harmonia axyridis is a ladybird native to Asia, but introduced widely as a biocontrol agent. It is invasive and detrimental to native species in North America, which meant its arrival in Britain was met with concern. Establishment was seen as an opportunity to track the spread of an invasive alien species (IAS) whilst also monitoring impacts on native species. The aims of this thesis were to examine the responses of native British ladybirds to the arrival of H. axyridis, to establish the effect of the IAS on native ladybirds when compared to other drivers, and to investigate the possible facilitation of the H. axyridis invasion by natural enemy release. Modelling ladybird distributions with life-history and resource-use traits found that species predatory on a wide range of prey families had larger range sizes than those which ate fewer prey types. This suggests that the wide diet breadth of the IAS is likely to have played a critical role in the species’ rapid spread. Dietary niche overlap between H. axyridis and native ladybirds showed positive correlation with declines of native ladybirds. This indicates that the IAS is playing an important role, but the significance of urbanisation suggests habitat destruction is also significant. Abundance of H. axyridis was influenced by habitat type and aphid abundance, but not by the native ladybird community, suggesting the spread of the IAS will not be slowed by biotic resistance. Harmonia axyridis is attacked by native parasitoids, but at a much lower rate than is the native Coccinella septempunctata, in line with natural-enemy release theory. There was no evidence of attack rate increasing with time since arrival in an area. Overall, H. axyridis is an extremely successful IAS, with detrimental effects on native ladybirds which are likely to continue.
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SORIA, GONZALEZ DE BUITRAGO CARMEN DIANA. "Projected effect of global change on species' change in extinction risk". Doctoral thesis, 2022. http://hdl.handle.net/11573/1652541.
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Climate change has become one of the major drivers of biodiversity loss, its effects are not only already evident across all levels of biological organization (from genes to ecosystems) but are projected to increase in the coming decades. The probability of a species or population being negatively impacted by climate change (i.e., risk) is determined by the occurrence of adverse climatic events or trends (i.e., hazard), the occurrence of the species or population in areas that could be impacted (i.e., exposure), and their predisposition to be adversely affected, including their sensitivity or susceptibility and lack of capacity to cope or adapt (i.e., vulnerability). Species or populations can adapt to adverse climatic conditions by shifting their geographical distribution or adapting in situ, generally by changing their phenology, morphology or physiology.
Recent efforts to assess the impacts of climate change have predominantly relied on bioclimatic niche modeling, which predicts species’ or populations’ distributions by linking their geographical range and bioclimatic variables. However, these models assume that all species are affected and will respond to climate change similarly, and do not consider differences in vulnerability and exposure. Trait-based assessments have aimed to address this gap, identifying which traits influence risk, allowing assessing multiple species simultaneously in a simple way and serving as a useful tool for prioritizing conservation actions, especially in the absence of distribution data. However, their applicability can be limited as they are not spatially explicit, the relationship between traits and responses is still uncertain, there are gaps in trait data availability and the approach is generally implemented at the species level, ignoring intraspecific differences in exposure, vulnerability and hazard. The objective of this thesis is to overcome some of these limitations for birds and terrestrial non-volant mammals.
To overcome gaps in mammal trait data availability, I compiled in my first chapter COMBINE: A Coalesced Mammal Database of Intrinsic and Extrinsic traits data for 54 traits for 6,234 mammal species, using data from 14 different data sources. These traits covered aspects such as physiology, reproduction, behavior, longevity, diet, and dispersal. I further filled in gaps in the data through a phylogenetic multiple imputation procedure, providing a complete dataset for 21 traits. All data sources and imputed data were flagged, facilitating identifying the origin of the data. This dataset constitutes a useful tool for large-scale ecological and conservation analyses that use traits, including identifying species at risk from climate change. In my second analytical chapter, Relative latitude, temperature increase and breadth of climatic niche influence mammal populations’ response to climate change, I identified current terrestrial non-volant mammal responses to climate change and the intrinsic traits and environmental factors influencing risk. To achieve this, I first performed a literature review on responses to climate change and categorized them into changes in (a) distribution and abundance, (b) phenology, and (c) morphology. I also identified the direction of each type of response: expansion or contraction for distribution and abundance, advance or delay for phenology, increase or decrease for body size, and no change if no response was detected. To model the relationship between risk from climate change and intrinsic and environmental factors, I focused exclusively on distribution and abundance responses due to their direct relationship. I then selected and obtained data for a series of intrinsic traits and environmental factors previously associated with climate change risk. To account for intraspecific variability in environmental factors, I identified populations of the species that experience similar climatic conditions. As these populations were distributed across large geographical areas, I grouped the responses by species and country, reducing the number of instances of opposing or mixed responses (i.e., different studies for the same species and country reporting distribution and abundance contractions and expansions or phenological advances and delays) and allowing the inclusion of the location of the response within the population. I obtained 382 responses belonging to 130 species located in 30 countries. Most of these responses were distribution and abundance responses (80.6%) while phenological and morphological changes constituted 4.5% (17 responses) and 10.2% (39 responses) respectively. The remaining 4.7% did not fit into any of these categories. Regarding distribution and abundance responses, there were more than twice as many contractions (46.43%) as expansions (20.78%), while in 32.79% of cases there was no clear response. The results of our model indicated that contractions were more likely at the warm edge of the population, while expansions were more likely at the cold edge. Small litter size, hibernation, high temperature increase, low climate seasonality and low altitudinal breadth were also linked to an elevated risk of experiencing a negative response.
In my third analytical chapter, Local environmental factors influence bird distribution and phenological responses to climate change, I followed the same approach but focused on bird distribution and abundance and spring phenological responses to climate change. I also gathered data for nine intrinsic bird traits that have been previously hypothesized to be relevant in determining responses to climate change. This allowed me to identify which intrinsic traits and environmental factors influence experiencing distribution contractions or expansions and spring phenological advances, delays or no changes. I obtained 3,012 responses for 918 species located in 32 countries, 60% of them were distribution and abundance responses and the remaining 40% were spring phenology responses. I found that environmental factors played an important role in determining both distribution and abundance and phenological responses to climate change. Maximum temperature, restricted climate seasonality, relative latitudinal position, and maximum longevity influenced the probability of experiencing contractions and a subsequent increase in risk. Similarly, maximum temperature, climate seasonality, relative latitudinal position, and temperature increase influenced the probability of experiencing advances in spring phenology.
The results presented in this thesis constitute an advance in current knowledge on the variables influencing responses to climate change locally and serve as a starting point for future research.
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Krause, Benjamin. "Landscape change and impoverishment in North German grasslands since the 1950s". Doctoral thesis, 2013. http://hdl.handle.net/11858/00-1735-0000-0022-5F67-0.
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Die Kulturlandschaft und ihre Bewirtschaftung haben sich seit dem Beginn der großräumigen Intensivierungsprozesse (z.B. Meliorationen, synthetischer Düngung und Herbizidgebrauch) in den 1950/60er Jahren in Mitteleuropa dramatisch geändert. Viele der ehemaligen artenreichen Grünlandflächen wurden in den letzten Jahrzehnten beseitigt (z.B. durch Umbruch zu Acker). Dies führte zu einem allgemeinen Grünlandrückgang in Deutschland. Heute werden die meisten Ackerflächen und die restlichen Grünlandflächen sehr intensiv bewirtschaftet. Die gegenläufige Entwicklung, die Umwandlung von Äckern zu Grünland, ist eher eine regionale Erscheinung, z.B. im Hügeland oder im Zuge von Kompensationsmaßnahmen. Die Artenzusammensetzung dieser Grünländer unterscheidet sich jedoch häufig von solchen mit längerer Habitatkontinuität. Um die Effekte von solch weiträumigen Meliorationsmaßnahmen auf die Phytodiversität, die Landschaftsstruktur und die hiermit einhergehende Grünlandfragmentierung sowie deren Auswirkungen auf die Pflanzenarten des Grünlandes zu erfassen, ist es nötig, historische Daten aus den 1950er Jahren, bevor die gravierenden, ackerbaulichen Intensivierungen begannen, auszuwerten.
Feucht- sowie artenreiche Frischgrünländer waren in den 1950/60er Jahren ein typischer und weit verbreiteter Habitattyp, gelten jedoch aktuell als sehr bedroht in Mitteleuropa. Wiederholungsstudien mit mehreren Untersuchungsflächen und einem Untersuchungs-zeitraum von 50-60 Jahren, der vor den weiträumigen Intensivierungen beginnt, fehlen bislang und klar verortete historische Vegetationsdaten sind selten. Obwohl der Graslandanteil in einigen Hügelregionen in Deutschland zugenommen hat ist die ökologische Qualität vieler dieser Flächen gering. Zusätzlich sind artenreiche Kalkmagerrasen als ein Relikt früherer Bewirtschaftsformen und typischer Bestandteil des Hügellandes durch Nutzungsaufgabe (Sukzession) und Nährstoffeintrag gefährdet.
Das Ziel dieser Doktorarbeit war es, den Landschaftswandel und die Veränderungen im Grünland in sechs Flussauengebieten (sowie einem durch Naturschutzstatus geschützten Gebiet) und einem typischen Gebiet des Hügellandes in Norddeutschland zu untersuchen. Hierzu wurden sowohl der Grünlandanteil, die Habitatkontinuität, der aktuelle Habitattyp, der Fragmentierungsgrad als auch die Auswirkungen auf die Artenzahlen, Artenzusammensetzung und die funktionelle Diversität untersucht. Die Studien in den Flussauen basieren auf fein aufgelösten historischen Vegetationskarten und dazugehörigen Vegetationsaufnahmen aus demselben Zeitraum. In 2008 wurden diese sechs Gebiete (+1 geschütztes Gebiet) mittels einer Biotoptypenkartierung erneut erfasst. Innerhalb dieser kanpp 2800 ha (2500 + 293 ha) früherer Grünländer wurden randomisierte Punkte gelegt und zusätzlich Vegetationaufnahmen in allen aktuellen Grünländern (inklusive Sukzessionsstadien) angefertigt.
Die Fallstudie (2500 ha) aus dem niedersächsischen Hügelland basiert auf aktuellen Vegetationsaufnahmen, die ebenfalls mittels randomisierter Punkte in den bestehenden Grünländern (394 ha) angefertig wurden. Zusatzdaten über z.B. die aktuelle Bewirtschaftung oder die Habitatkontinuität (Auswertung historischer Karten) wurden ebenfalls erfasst.
Die erste Studie zeigte, dass die ehemaligen artenreichen Feucht- und Frischgrünländer in den ungeschützten Gebieten drastisch, um über 80% der ursprünglichen Fläche, zurückgegangen sind. Sie wurden größtenteils durch Äcker, Intensivgrünländer aber auch Brachestadien ersetzt. Bedingt durch diesen starken Flächenrückgang hat die Fragmentierung der Restflächen stark zugenommen. Die durch ein Naturschutzgebiet geschützte Untersuchungsfläche an der Havel zeigte im Vergleich relative geringe Veränderungen. Daraus lässt sich deuten, dass lokale Effekte wie Düngung oder Drainage und nicht überregionale Effekte wie Klimaerwärmung oder der Eintrag von Stickstoff durch Luft die Hauptursache für den dokumentierten Wandel sind.
Die zweite Studie in den Grünländern der Auen zeigte, dass sich die Artenzusammensetzung in den letzten fünf bis sechs Jahrzehnten in allen Gebieten stark verändert hat, die Artenzahlen der Vegetationsaufnahmen um 30-50% und auch die funktionelle Diversität in ähnlichem Maße zurückgegangen sind. Die Ellenberg-Zeigerwerte (EIV) für Nährstoffverfügbarkeit sind im Vergleich zu den 1950/60er Jahren stark gestiegen und die Unterschiede zwischen den ungeschützen und dem geschützten Gebiet unterstützen ebenfalls die Annahme, dass Veränderungen größtenteils durch lokale Faktoren und nicht durch überregionale Effekte verursacht wurden. Der Trend in den ungeschützten Gebieten geht zu artenamen Grünlandgesellschaften, die von wenigen konkurrenzstarken und mahdtoleranten Arten dominiert werden. Frühblühende und auf Insektenbestäubung angewiesene Pflanzen sind stark zurückgegangen, mit entsprechenden Auswirkungen auf die Tierwelt.
Die dritte Studie verknüpft den dramatischen Grünlandrückgang und die zunehmende Fragmentierung mit der Artenverarmung seit den 1950/60er Jahren. Hierfür wurden mittels definierter Kriterien eine Liste von 78 für das Feucht- und Frischgrünland charakteristischen Grünlandarten definiert, die die Grundlage für die weiteren Analysen bildeten. Die Artenzahlen auf Ebene der Vegetationsaufnahmen nahmen um 30-66% ab. Die getesteten Landschaftsstrukturmaße hatten keinen nachweisbaren Einfluss auf die Artenzahlen auf Landschaftsebene. Die Distanz zum nächstgelegenen und geeigneten Habitat für die charakteristischen Arten hatte einen geringen negativen Effekt auf die Artenzahl der Vegetationsaufnahmen. Die Ellenberg-Zeigerwerte (N, F) und die Diversitätsmaßzahlen an charakteristischen Arten weisen ebenfalls auf den Effekt der lokalen Bewirtschaftung und nicht auf Fragmentierung als treibende Kraft beim Rückgang und dem Wandel der Artengarnitur hin.
Im Gegensatz zu den Untersuchungsgebieten in den Flussauen hat sich der Grünlandanteil in der Fallstudie im niedersächsischen Hügelland seit den 1950er Jahren verdoppelt. Es wurden sechs verschiedene Grünlandtypen mit einer Spanne von unter 15 bis zu deutlich mehr als 27 Arten pro Aufnahme erfasst. Die besonders artenreichen Bestände sind aber mit ca. 6% der Fläche sehr selten. Die Anzahl an insektenbestäubten Pflanzen als auch die absoluten Artenzahlen gehen mit steigender Nutzungsintensität (indiziert durch die Ellenberg-Zeigerwerte Nährstoffe (N) und Mahdtoleranz (M)) wie in den Untersuchungsgebieten in den Flussauen zurück. Artenreiche Grünländer kommen nur auf mit Schafen beweideten Flächen mit einer Habitatkontinuität von mindestens 100 Jahren vor. Grünländer mit mittleren Artenzahlen sind größtenteils auf früheren Äckern mit einer Habitatkontinuität von weniger als 30 Jahren zu finden.
Die dargestellte Untersuchung hat dramatische Verluste in den Grünlandflächen der Flussauen aufgezeigt. Die Restflächen sind fragmentiert und die Artenzahlen sowie die funtionelle Diversität stark zurückgegangen. Die Fallstudie im niedersächsischen Hügelland zeigt, dass selbst in Landschaften mit hohem Grasslandanteil die ökologische Qualität von den meisten Grünländern nur noch gering ist.
Libros sobre el tema "Traités – Extinction"
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pseud, Piper Watty y Lustig Loretta ill, eds. The little engine that could: And the fire rescue. New York: Platt & Munk, 2003.
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Courtney, Richard. Flynn saves the day. New York: Random House, 2011.
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van Dooren, Thom. A World in a Shell. The MIT Press, 2022. http://dx.doi.org/10.7551/mitpress/14579.001.0001.
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Following the trails of Hawai'i's snails to explore the simultaneously biological and cultural significance of extinction. In this time of extinctions, the humble snail rarely gets a mention. And yet snails are disappearing faster than any other species. In A World in a Shell, Thom van Dooren offers a collection of snail stories from Hawai'i—once home to more than 750 species of land snails, almost two-thirds of which are now gone. Following snail trails through forests, laboratories, museums, and even a military training facility, and meeting with scientists and Native Hawaiians, van Dooren explores ongoing processes of ecological and cultural loss as they are woven through with possibilities for hope, care, mourning, and resilience. Van Dooren recounts the fascinating history of snail decline in the Hawaiian Islands: from deforestation for agriculture, timber, and more, through the nineteenth century shell collecting mania of missionary settlers, and on to the contemporary impacts of introduced predators. Along the way he asks how both snail loss and conservation efforts have been tangled up with larger processes of colonization, militarization, and globalization. These snail stories provide a potent window into ongoing global process of environmental and cultural change, including the largely unnoticed disappearance of countless snails, insects, and other less charismatic species. Ultimately, van Dooren seeks to cultivate a sense of wonder and appreciation for our damaged planet, revealing the world of possibilities and relationships that lies coiled within a snail's shell.
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Frankham, Richard, Jonathan D. Ballou, Katherine Ralls, Mark D. B. Eldridge, Michele R. Dudash, Charles B. Fenster, Robert C. Lacy y Paul Sunnucks. Inbreeding reduces reproductive fitness. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780198783398.003.0003.
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The harmful impacts of inbreeding are generally greater in species that naturally outbreed compared to those in inbreeding species, greater in stressful than benign environments, greater for fitness than peripheral traits, and greater for total fitness compared to its individual components. Inbreeding reduces survival and reproduction (i.e., it causes inbreeding depression), and thereby increases the risk of extinction. Inbreeding depression is due to increased homozygosity for harmful alleles and at loci exhibiting heterozygote advantage. Natural selection may remove (purge) the alleles that cause inbreeding depression, especially following inbreeding or population bottlenecks, but it has limited effects in small populations and usually does not completely eliminate inbreeding depression. Inbreeding depression is nearly universal in sexually reproducing organisms that are diploid or have higher ploidies.
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James, Philip. Temporal patterns. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198827238.003.0007.
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Beginning in the Far East over 2000 years ago the discussion in this chapter charts the movement of species found in contemporary urban environments around the globe. A city is dependent on trade for the resources required by the inhabitants to live and work. Some items of trade are plants and animals, and over time, many species have been introduced intentionally, and many others unintentionally (perhaps as a result of hitching a lift in or on items being traded between countries and continents) to become part of the urban flora and fauna. All the time that such global dispersal has been occurring, some floral and faunal species originally present in an urban area have become locally extinct. These processes of invasion and extinction are controlled by filters and process, and there are certain traits, the possession of which is seemingly beneficial to organisms in urban environments.
Capítulos de libros sobre el tema "Traités – Extinction"
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Cavender-Bares, Jeannine, John A. Gamon y Philip A. Townsend. "The Use of Remote Sensing to Enhance Biodiversity Monitoring and Detection: A Critical Challenge for the Twenty-First Century". En Remote Sensing of Plant Biodiversity, 1–12. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-33157-3_1.
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AbstractImproved detection and monitoring of biodiversity is critical at a time when the Earth’s biodiversity loss due to human activities is accelerating at an unprecedented rate. We face the largest loss of biodiversity in human history, a loss which has been called the “sixth mass extinction” (Leakey 1996; Kolbert 2014), given that its magnitude is in proportion to past extinction episodes in Earth history detectable from the fossil record. International efforts to conserve biodiversity (United Nations 2011) and to develop an assessment process to document changes in the status and trends of biodiversity globally through the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (Díaz et al. 2015) have raised awareness about the critical need for continuous monitoring of biodiversity at multiple spatial scales across the globe. Biodiversity itself—the variation in life found among ecosystems and organisms at any level of biological organization—cannot practically be observed everywhere. However, if habitats, functional traits, trait diversity, and the spatial turnover of plant functions can be remotely sensed, the potential exists to globally inventory the diversity of habitats and traits associated with terrestrial biodiversity. To face this challenge, there have been recent calls for a global biodiversity monitoring system (Jetz et al. 2016; Proença et al. 2017; The National Academy of Sciences 2017). A central theme of this volume is that remote sensing (RS) will play a key role in such a system.
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Yamamichi, Masato. "Effects of Rapid Evolution on Population Cycles and Extinction in Predator–Prey Systems". En Diversity of Functional Traits and Interactions, 19–49. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-7953-0_2.
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Preston, Christopher J. "De-extinction and Gene Drives: The Engineering of Anthropocene Organisms". En The International Library of Environmental, Agricultural and Food Ethics, 495–511. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-63523-7_27.
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AbstractAdvances in gene reading, gene synthesis, and genome editing are making possible a number of radical new practices for transforming animal futures in the Anthropocene. De-extinction may make it possible to bring back lost species. Gene drives may enable the sending of desirable traits through wild populations of organisms. The hype accompanying these promises can make each of them look ethically irresistible. This chapter investigates the ‘speculative ethics’ that has arisen around these technologies, asking questions about both their viability and the approach to animals they contain. Reductive and non-relational thinking is identified as one potential problem with the thinking behind these techniques. The neglect of non-human agency is identified as another. After indicating some of the problems these two ways of conceptualizing an animal and its genome can create, a brief suggestion is made about how to better conceptualize animal futures in the Anthropocene.
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Bauer, G. "Plasticity in Life History Traits of the Freshwater Pearl Mussel — Consequences for the Danger of Extinction and for Conservation Measures". En Species Conservation: A Population-Biological Approach, 103–20. Basel: Birkhäuser Basel, 1991. http://dx.doi.org/10.1007/978-3-0348-6426-8_8.
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Matzke, Nicholas J. "Science Without Species: Doing Science with Tree-Thinking". En Speciesism in Biology and Culture, 47–61. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-99031-2_3.
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AbstractThe focus of this volume is speciesism. While the concepts of species and speciation remain the focus of a great deal of research, it is worth exploring how in recent decades evolutionary biology has, in several ways, moved away from species as the key unit of analysis of biological questions. I begin by outlining how phylogenetic comparative methods have become essential methodological tools in statistical analyses of relationships between traits. Species are not statistically independent observations, because the reality is that they are related, genetically and statistically, on a phylogenetic tree. Phylogeny also plays a key role in modern analyses of spatial patterns in biodiversity, and in fact relying on phylogenetic biodiversity measures can avoid a number of problems created by attempting to impose a uniform species rank across different continents and clades. Similarly, a major challenge in modern studies of diversification and extinction concerns the units of analysis and how they are defined and recognized. Both “genus” and “species” are human-defined ranks imposed on the phylogenetic tree. The phylogenetic tree is the more fundamental reality that is produced by the macroevolutionary process, and it could include every level of gradation of genetic and morphological divergence. Once ranks are imposed upon it, a variety of methodological problems are created as scientists attempt to make these ranks standardized and comparable across different datasets and timescales. I outline how phylogenetic thinking might help provide a solution. I conclude with other examples where cutting-edge science is done with phylogenies without much need of the “species” rank—for example, in the battle against Covid-19.
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Arnold, Stevan J. "Speciation and Extinction of Lineages". En Evolutionary Quantitative Genetics, 339–85. Oxford University PressOxford, 2023. http://dx.doi.org/10.1093/oso/9780192859389.003.0020.
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Abstract This chapter focuses on the roles of speciation and extinction, as well as within-lineage evolutionary process (mutation, inheritance, selection, population size), in shaping adaptive radiations. We begin by pointing out that on theoretical grounds trait evolution associated with speciation is likely to make a smaller contribution than within-lineage processes. We then introduce a theoretical framework that allows us to assess the effects of trait evolution on sexual isolation, speciation, and radiation. Using a sequence of models, we show that the efficacy of the Fisher-Lande process depends on relaxing selection on female mating preferences or allowing random movement of natural selection optima. Finally, we turn to traits that influence resource utilization and competition between species. We show that random movement of natural selection optima of such traits can drive ecological radiation, isolation, and speciation.
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Rocha-Ortega, Maya, Rassim Khelifa, Emily L. Sandall, Charl Deacon, Xavier Sánchez-Rivero, Stefan Pinkert y Michael A. Patten. "Linking traits to extinction risk in Odonata". En Dragonflies and Damselflies, 343–58. 2a ed. Oxford University PressOxford, 2022. http://dx.doi.org/10.1093/oso/9780192898623.003.0024.
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Abstract Current species extinction rates are comparable to the five paleontological mass extinction events. To assess risk of species’ extinction, scientists have developed a range of metrics, among them the IUCN threat categorization. Odonates are the most comprehensively assessed insect group (nearly every species) through the IUCN Red List process, yet many species remain categorized as “data deficient.” Species’ ecological and functional traits can help alleviate data deficiencies such as abundance shortfalls in predicting extinction risk. This chapter identifies the commonly studied Odonata traits that may relate to their extinction risk. It summarizes current functional eco-evolutionary perspectives, community resiliency and functional redundancy, and proxies of extinction risk. It proposes a unified framework for predicting Odonata extinction risk from traits that incorporates geographic ranges and environmental data layers, while encouraging the integration of individual abundances, intraspecific variation, biotic interactions, and resolved phylogenies.
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Bond, W. J. "Assessing the risk of plant extinction due to pollinator and disperser failure". En Extinction Rates, 131–46. Oxford University PressOxford, 1995. http://dx.doi.org/10.1093/oso/9780198548294.003.0009.
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Abstract Ecology has contributed two major insights to the biology of extinction: large areas hold more species than smaller areas and larger populations persist longer than smaller ones. No comparable generalization has emerged from studies of ecological interactions. In this chapter I attempt a new approach to predicting extinction which explicitly includes the importance of interactions. The patterns that emerge are not used to make general statements on probable species loss but rather to identify general traits which increase extinction risk. I use the interaction between plants and their pollinators and dispersers as an example of this species-centred view. These reproductive mutualisms epitomize the subtle, complex web of interactions which, if broken by human actions, could cause a cascade of extinctions. Janzen (1974,1987) has eloquently drawn attention to the possible ‘extinction of ecological interactions’ in tropical forests as a result of habitat transformation. Similar concerns, focusing on pollination, have been raised in other parts of the world including pesticide-sprayed north-temperate woodlands (Kevan 1975), alpine meadows (Vogel and Westerkamp 1991), and eroded African range lands (F. W. Gess and S. K. Gess 1993).
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"Community Ecology of Stream Fishes: Concepts, Approaches, and Techniques". En Community Ecology of Stream Fishes: Concepts, Approaches, and Techniques, editado por Emmanuel A. Frimpong y Paul L. Angermeier. American Fisheries Society, 2010. http://dx.doi.org/10.47886/9781934874141.ch6.
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<em>Abstract</em>.—Species traits are used to study the functional organization of fish communities for a range of reasons, from simply reducing data dimensionality to providing mechanistic explanations for observed variation in communities. Ecological and life history traits have been used to understand the basic ecology of fishes and predict (1) species and community responses to habitat and climate alteration, and (2) species extinction, species invasion, and community homogenization. Many approaches in this arena have been developed during the past three decades, but they often have not been integrated with related ecological concepts or subdisciplines, which has led to confusion in terminology. We review 102 studies of species traits and then summarize patterns in traits being used and questions being addressed with trait-based approaches. Overall, studies of fish–habitat relationships that apply habitat templates and hierarchical filters dominate our sample; the most frequently used traits are related to feeding. We define and show the relationships among key terms such as fundamental and realized niches; functional traits, performance, and fitness; tactic, trait-state, syndromes, and strategies; and guilds and functional groups. We propose accelerating research to (1) quantify trait plasticity, (2) identify traits useful for testing ecological hypotheses, (3) model habitat and biotic interactions in communities while explicitly accounting for phylogenetic relationships, (4) explore how traits control community assembly, and (5) document the importance of traits in fish– community responses to anthropogenic change and in delivering ecosystem services. Further synthesis of these topics is still needed to develop concepts, models, and principles that can unify the disparate approaches taken in trait-based analysis of fish communities, link fish community ecology to general community ecology, and inform sustainable management of ecosystems.
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Bennett, Peter M. y Ian P. F. Owens. "Comparative methods". En Evolutionary Ecology of Birds, 6–26. Oxford University PressOxford, 2002. http://dx.doi.org/10.1093/oso/9780198510888.003.0002.
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Abstract Bird species exhibit enormous diversity in morphology, behaviour, and ecology. In this book we attempt to explain why variability in life-history traits, mating systems, and extinction patterns exists across a wide range of bird species. We do this by making comparisons among taxa to test hypotheses about the adaptive significance of variation in these traits. In this section we present the theoretical and methodological basis for our work.
Actas de conferencias sobre el tema "Traités – Extinction"
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Carvalho, Filipe, Aino Juslén y Pedro Cardoso. "Which traits predispose species to extinction? A review". En 5th European Congress of Conservation Biology. Jyväskylä: Jyvaskyla University Open Science Centre, 2018. http://dx.doi.org/10.17011/conference/eccb2018/108095.
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Moor, Helen, Jenni Nordén, Juha Siitonen y Tord Snäll. "Do traits explain colonization-extinction rates of wood-decaying fungi?" En 5th European Congress of Conservation Biology. Jyväskylä: Jyvaskyla University Open Science Centre, 2018. http://dx.doi.org/10.17011/conference/eccb2018/107967.
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Monarrez, Pedro, Noel A. Heim y Jonathan Payne. "ALTERNATING MACROEVOLUTIONARY REGIMES: ARE ORGANISMAL TRAITS PREFERENTIALLY SELECTED OVER EMERGENT TRAITS DURING MASS EXTINCTIONS?" En GSA Connects 2021 in Portland, Oregon. Geological Society of America, 2021. http://dx.doi.org/10.1130/abs/2021am-366393.
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Rojas, Daniel, Bruce Lieberman, Brendan M. Anderson, Jonathan Hendricks y Roger W. Portell. "ESTIMATING THE NET EFFECT OF FUNCTIONAL TRAITS ON EXTINCTION IN PLIOCENE TO MODERN MOLLUSKS". En GSA Connects 2023 Meeting in Pittsburgh, Pennsylvania. Geological Society of America, 2023. http://dx.doi.org/10.1130/abs/2023am-389992.
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Davidovich, Luiz. "Entanglement and Decoherence". En Workshop on Entanglement and Quantum Decoherence. Washington, D.C.: Optica Publishing Group, 2008. http://dx.doi.org/10.1364/weqd.2008.ed1.
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The interaction between entangled multi-particle systems with the environment leads to both local dynamics, associated with single-particle dissipation, diffusion, and decay, and to global dynamics, which may provoke the disappearance of entanglement at a finite time [1-6]. This phenomenon may occur even when single-particle decoherence is asymptotic in time, and constitutes yet another distinct trait of entanglement. It has been recently demonstrated, for two qubits under the action of independent environments, using an all-optical setup [7]. In this talk, some of the peculiarities of the dynamics of two-qubit entangled states undergoing decoherence will be reviewed, new features of the experiment realized at the Federal University of Rio de Janeiro [7] will be described, and the extension of these considerations to multi-particle entangled states will be discussed. Scaling laws for the decay of entanglement and its finite-time extinction in multi-particle systems will be discussed.