Articles de revues : « Traités – Extinction »

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Napoleon, Val. « Extinction by Number : Colonialism Made Easy ». Canadian journal of law and society 16, n^o 1 (avril 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 mai 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 et 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 (juin 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 et 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, et 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 octobre 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 et Jonathan E. M. Baillie. « Predicting how populations decline to extinction ». Philosophical Transactions of the Royal Society B : Biological Sciences 366, n^o 1577 (12 septembre 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 et Samuel Pironon. « Mutualistic interactions reshuffle the effects of climate change on plants across the tree of life ». Science Advances 5, n^o 5 (mai 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 et Paulo Jose Almeida. « Body size and extinction risk in Brazilian carnivores ». Biota Neotropica 9, n^o 2 (juin 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.

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Martins, Maria João Fernandes, Gene Hunt, Carmi Milagros Thompson, Rowan Lockwood, John P. Swaddle et T. Markham Puckett. « Shifts in sexual dimorphism across a mass extinction in ostracods : implications for sexual selection as a factor in extinction risk ». Proceedings of the Royal Society B : Biological Sciences 287, n^o 1933 (19 août 2020) : 20200730. http://dx.doi.org/10.1098/rspb.2020.0730.

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Sexual selection often favours investment in expensive sexual traits that help individuals compete for mates. In a rapidly changing environment, however, allocation of resources to traits related to reproduction at the expense of those related to survival may elevate extinction risk. Empirical testing of this hypothesis in the fossil record, where extinction can be directly documented, is largely lacking. The rich fossil record of cytheroid ostracods offers a unique study system in this context: the male shell is systematically more elongate than that of females, and thus the sexes can be distinguished, even in fossils. Using mixture models to identify sex clusters from size and shape variables derived from the digitized valve outlines of adult ostracods, we estimated sexual dimorphism in ostracod species before and after the Cretaceous/Palaeogene mass extinction in the United States Coastal Plain. Across this boundary, we document a substantial shift in sexual dimorphism, driven largely by a pronounced decline in the taxa with dimorphism indicating both very high and very low male investment. The shift away from high male investment, which arises largely from evolutionary changes within genera that persist through the extinction, parallels extinction selectivity previously documented during the Late Cretaceous under a background extinction regime. Our results suggest that sexual selection and the allocation of resources towards survival versus reproduction may be an important factor for species extinction during both background and mass extinctions.

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Ruta, Marcello, Kenneth D. Angielczyk, Jörg Fröbisch et Michael J. Benton. « Decoupling of morphological disparity and taxic diversity during the adaptive radiation of anomodont therapsids ». Proceedings of the Royal Society B : Biological Sciences 280, n^o 1768 (7 octobre 2013) : 20131071. http://dx.doi.org/10.1098/rspb.2013.1071.

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Adaptive radiations are central to macroevolutionary theory. Whether triggered by acquisition of new traits or ecological opportunities arising from mass extinctions, it is debated whether adaptive radiations are marked by initial expansion of taxic diversity or of morphological disparity (the range of anatomical form). If a group rediversifies following a mass extinction, it is said to have passed through a macroevolutionary bottleneck, and the loss of taxic or phylogenetic diversity may limit the amount of morphological novelty that it can subsequently generate. Anomodont therapsids, a diverse clade of Permian and Triassic herbivorous tetrapods, passed through a bottleneck during the end-Permian mass extinction. Their taxic diversity increased during the Permian, declined significantly at the Permo–Triassic boundary and rebounded during the Middle Triassic before the clade's final extinction at the end of the Triassic. By sharp contrast, disparity declined steadily during most of anomodont history. Our results highlight three main aspects of adaptive radiations: (i) diversity and disparity are generally decoupled; (ii) models of radiations following mass extinctions may differ from those triggered by other causes (e.g. trait acquisition); and (iii) the bottleneck caused by a mass extinction means that a clade can emerge lacking its original potential for generating morphological variety.

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Harnik, Paul G., Paul C. Fitzgerald, Jonathan L. Payne et Sandra J. Carlson. « Phylogenetic signal in extinction selectivity in Devonian terebratulide brachiopods ». Paleobiology 40, n^o 4 (2014) : 675–92. http://dx.doi.org/10.1666/14006.

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Determining which biological traits affect taxonomic durations is critical for explaining macroevolutionary patterns. Two approaches are commonly used to investigate the associations between traits and durations and/or extinction and origination rates: analyses of taxonomic occurrence patterns in the fossil record and comparative phylogenetic analyses, predominantly of extant taxa. By capitalizing upon the empirical record of past extinctions, paleontological data avoid some of the limitations of existing methods for inferring extinction and origination rates from molecular phylogenies. However, most paleontological studies of extinction selectivity have ignored phylogenetic relationships because there is a dearth of phylogenetic hypotheses for diverse non-vertebrate higher taxa in the fossil record. This omission inflates the degrees of freedom in statistical analyses and leaves open the possibility that observed associations are indirect, reflecting shared evolutionary history rather than the direct influence of particular traits on durations. Here we investigate global patterns of extinction selectivity in Devonian terebratulide brachiopods and compare the results of taxonomic vs. phylogenetic approaches. Regression models that assume independence among taxa provide support for a positive association between geographic range size and genus duration but do not indicate an association between body size and genus duration. Brownian motion models of trait evolution identify significant similarities in body size, range size, and duration among closely related terebratulide genera. We use phylogenetic regression to account for shared evolutionary history and find support for a significant positive association between range size and duration among terebratulides that is also phylogenetically structured. The estimated range size–duration relationship is moderately weaker in the phylogenetic analysis due to the down-weighting of closely related genera that were both broadly distributed and long lived; however, this change in slope is not statistically significant. These results provide evidence for the phylogenetic conservatism of organismal and emergent traits, yet also the general phylogenetic independence of the relationship between range size and duration.

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Lima-Ribeiro, Matheus S., Joaquín Hortal, Sara Varela et José Alexandre F. Diniz-Filho. « Constraint envelope analyses of macroecological patterns reveal climatic effects on Pleistocene mammal extinctions ». Quaternary Research 82, n^o 1 (juillet 2014) : 260–69. http://dx.doi.org/10.1016/j.yqres.2014.02.003.

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AbstractQuantitative analysis of macroecological patterns for late Pleistocene assemblages can be useful for disentangling the causes of late Quaternary extinctions (LQE). However, previous analyses have usually assumed linear relationships between macroecological traits, such as body size and range size/range shift, that may have led to erroneous interpretations. Here, we analyzed mammalian datasets to show how macroecological patterns support climate change as an important driver of the LQE, which is contrary to previous analyses that did not account for more complex relationships among traits. We employed quantile regression methods that allow a detailed and fine-tuned quantitative analysis of complex macroecological patterns revealed as polygonal relationships (i.e., constraint envelopes). We showed that these triangular-shaped envelopes that describe the macroecological relationship between body size and geographical range shift reflect nonrandom extinction processes under which the large-bodied species are more prone to extinction during events of severe habitat loss, such as glacial/interglacial transitions. Hence, we provide both a theoretical background and methodological framework to better understand how climate change induces body size-biased species sorting and shapes complex macroecological patterns.

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Jablonski, David, Karl W. Flessa et James W. Valentine. « Biogeography and paleobiology ». Paleobiology 11, n^o 1 (1985) : 75–90. http://dx.doi.org/10.1017/s0094837300011416.

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In the past decade paleobiologists have applied the techniques of both ecological and historical biogeography, although vicariance/cladistic approaches have as yet had minimal impact. The traditional focus of paleobiogeographic study has been the province, a statistical entity defined by clusters of range endpoints of individual taxa. The study of such provinces has been useful in inferring past continental positions (although ambiguities remain that must be resolved using independent geological criteria) and in understanding the role of past global geographies in regulating biotic diversity through changes in the numbers and extent of provinces. This approach can be complemented by the treatment of geographic ranges of taxa as irreducible or emergent traits with far-reaching evolutionary effects upward and downward within a genealogical hierarchy. Temperature tolerances in benthic marine organisms appear to be by-products of selection for enzyme structures imparting favorable activity levels within the normal temperature range rather than direct products of selection for resistance to temperature extremes. Thus geographic range endpoints, which are also influenced by dispersal capability and the resulting scale of gene flow among disjunct populations, are not direct products of selection. However, the magnitudes of geographic ranges of species and clades behave as emergent properties and significantly influence taxonomic survivorship during background and mass extinctions in ways that are not extrapolations of effects at lower hierarchical levels. Biogeography shapes macroevolutionary patterns of origination and extinction during times of normal, background extinction and mass extinction. Preferential extinction among regions or among endemic rather than widespread clades can result in strong biases in the nature of the survivors of mass extinctions, with taxa being lost not because of selection against attributes of individual organisms but because of higher-order patterns of geographic selectivity.

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Juan-Jordá, M. J., I. Mosqueira, J. Freire et N. K. Dulvy. « Population declines of tuna and relatives depend on their speed of life ». Proceedings of the Royal Society B : Biological Sciences 282, n^o 1811 (22 juillet 2015) : 20150322. http://dx.doi.org/10.1098/rspb.2015.0322.

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Larger-bodied species in a wide range of taxonomic groups including mammals, fishes and birds tend to decline more steeply and are at greater risk of extinction. Yet, the diversity in life histories is governed not only by body size, but also by time-related traits. A key question is whether this size-dependency of vulnerability also holds, not just locally, but globally across a wider range of environments. We test the relative importance of size- and time-related life-history traits and fishing mortality in determining population declines and current exploitation status in tunas and their relatives. We use high-quality datasets of half a century of population trajectories combined with population-level fishing mortalities and life-history traits. Time-related traits (e.g. growth rate), rather than size-related traits (e.g. maximum size), better explain the extent and rate of declines and current exploitation status across tuna assemblages, after controlling for fishing mortality. Consequently, there is strong geographical patterning in population declines, such that populations with slower life histories (found at higher cooler latitudes) have declined most and more steeply and have a higher probability of being overfished than populations with faster life histories (found at tropical latitudes). Hence, the strong, temperature-driven, latitudinal gradients in life-history traits may underlie the global patterning of population declines, fisheries collapses and local extinctions.

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Arbuckle, Kevin. « Chemical antipredator defence is linked to higher extinction risk ». Royal Society Open Science 3, n^o 11 (novembre 2016) : 160681. http://dx.doi.org/10.1098/rsos.160681.

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Many attributes of species may be linked to contemporary extinction risk, though some such traits remain untested despite suggestions that they may be important. Here, I test whether a trait associated with higher background extinction rates, chemical antipredator defence, is also associated with current extinction risk, using amphibians as a model system—a group facing global population declines. I find that chemically defended species are approximately 60% more likely to be threatened than species without chemical defence, although the severity of the contemporary extinction risk may not relate to chemical defence. The results confirm that background and contemporary extinction rates can be predicted from the same traits, at least in certain cases. This suggests that associations between extinction risk and phenotypic traits can be temporally stable over long periods. The results also provide novel insights into the relevance of antipredator defences for species subject to conservation concerns.

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Leitão, Rafael P., Jansen Zuanon, Sébastien Villéger, Stephen E. Williams, Christopher Baraloto, Claire Fortunel, Fernando P. Mendonça et David Mouillot. « Rare species contribute disproportionately to the functional structure of species assemblages ». Proceedings of the Royal Society B : Biological Sciences 283, n^o 1828 (13 avril 2016) : 20160084. http://dx.doi.org/10.1098/rspb.2016.0084.

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There is broad consensus that the diversity of functional traits within species assemblages drives several ecological processes. It is also widely recognized that rare species are the first to become extinct following human-induced disturbances. Surprisingly, however, the functional importance of rare species is still poorly understood, particularly in tropical species-rich assemblages where the majority of species are rare, and the rate of species extinction can be high. Here, we investigated the consequences of local and regional extinctions on the functional structure of species assemblages. We used three extensive datasets (stream fish from the Brazilian Amazon, rainforest trees from French Guiana, and birds from the Australian Wet Tropics) and built an integrative measure of species rarity versus commonness, combining local abundance, geographical range, and habitat breadth. Using different scenarios of species loss, we found a disproportionate impact of rare species extinction for the three groups, with significant reductions in levels of functional richness, specialization, and originality of assemblages, which may severely undermine the integrity of ecological processes. The whole breadth of functional abilities within species assemblages, which is disproportionately supported by rare species, is certainly critical in maintaining ecosystems particularly under the ongoing rapid environmental transitions.

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Malanoski, Cooper M., Alex Farnsworth, Daniel J. Lunt, Paul J. Valdes et Erin E. Saupe. « Climate change is an important predictor of extinction risk on macroevolutionary timescales ». Science 383, n^o 6687 (8 mars 2024) : 1130–34. http://dx.doi.org/10.1126/science.adj5763.

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Anthropogenic climate change is increasing rapidly and already impacting biodiversity. Despite its importance in future projections, understanding of the underlying mechanisms by which climate mediates extinction remains limited. We present an integrated approach examining the role of intrinsic traits versus extrinsic climate change in mediating extinction risk for marine invertebrates over the past 485 million years. We found that a combination of physiological traits and the magnitude of climate change is necessary to explain marine invertebrate extinction patterns. Our results suggest that taxa previously identified as extinction resistant may still succumb to extinction if the magnitude of climate change is great enough.

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Stanley, Steven M. « Memoir 4 : An Analysis of the History of Marine Animal Diversity ». Paleobiology 33, S4 (2007) : 1–55. http://dx.doi.org/10.1017/s0094837300019217.

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According to when they attained high diversity, major taxa of marine animals have been clustered into three groups, the Cambrian, Paleozoic, and Modern Faunas. Because the Cambrian Fauna was a relatively minor component of the total fauna after mid-Ordovician time, the Phanerozoic history of marine animal diversity is largely a matter of the fates of the Paleozoic and Modern Faunas. The fact that most late Cenozoic genera belong to taxa that have been radiating for tens of millions of years indicates that the post-Paleozoic increase in diversity indicated by fossil data is real, rather than an artifact of improvement of the fossil record toward the present.Assuming that ecological crowding produced the so-called Paleozoic plateau for family diversity, various workers have used the logistic equation of ecology to model marine animal diversification as damped exponential increase. Several lines of evidence indicate that this procedure is inappropriate. A plot of the diversity of marine animal genera through time provides better resolution than the plot for families and has a more jagged appearance. Generic diversity generally increased rapidly during the Paleozoic, except when set back by pulses of mass extinction. In fact, an analysis of the history of the Paleozoic Fauna during the Paleozoic Era reveals no general correlation between rate of increase for this fauna and total marine animal diversity. Furthermore, realistically scaled logistic simulations do not mimic the empirical pattern. In addition, it is difficult to imagine how some fixed limit for diversity could have persisted throughout the Paleozoic Era, when the ecological structure of the marine ecosystem was constantly changing. More fundamentally, the basic idea that competition can set a limit for marine animal diversity is incompatible with basic tenets of marine ecology: predation, disturbance, and vagaries of recruitment determine local population sizes for most marine species. Sparseness of predators probably played a larger role than weak competition in elevating rates of diversification during the initial (Ordovician) radiation of marine animals and during recoveries from mass extinctions. A plot of diversification against total diversity for these intervals yields a band of points above the one representing background intervals, and yet this band also displays no significant trend (if the two earliest intervals of the initial Ordovician are excluded as times of exceptional evolutionary innovation). Thus, a distinctive structure characterized the marine ecosystem during intervals of evolutionary radiation—one in which rates of diversification were exceptionally high and yet increases in diversity did not depress rates of diversification.Particular marine taxa exhibit background rates of origination and extinction that rank similarly when compared with those of other taxa. Rates are correlated in this way because certain heritable traits influence probability of speciation and probability of extinction in similar ways. Background rates of origination and extinction were depressed during the late Paleozoic ice age for all major marine invertebrate taxa, but remained correlated. Also, taxa with relatively high background rates of extinction experienced exceptionally heavy losses during biotic crises because background rates of extinction were intensified in a multiplicative manner; decimation of a large group of taxa of this kind in the two Permian mass extinctions established their collective identity as the Paleozoic Fauna.Characteristic rates of origination and extinction for major taxa persisted from Paleozoic into post-Paleozoic time. Because of the causal linkage between rates of origination and extinction, pulses of extinction tended to drag down overall rates of origination as well as overall rates of extinction by preferentially eliminating higher taxa having relatively high background rates of extinction. This extinction/origination ratchet depressed turnover rates for the residual Paleozoic Fauna during the Mesozoic Era. A decline of this fauna's extinction rate to approximately that of the Modern Fauna accounts for the nearly equal fractional losses experienced by the two faunas in the terminal Cretaceous mass extinction.Viewed arithmetically, the fossil record indicates slow diversification for the Modern Fauna during Paleozoic time, followed by much more rapid expansion during Mesozoic and Cenozoic time. When viewed more appropriately as depicting geometric—or exponential—increase, however, the empirical pattern exhibits no fundamental secular change: the background rate of increase for the Modern Fauna—the fauna that dominated post-Paleozoic marine diversity—simply persisted, reflecting the intrinsic origination and extinction rates of constituent taxa. Persistence of this overall background rate supports other evidence that the empirical record of diversification for marine animal life since Paleozoic time represents actual exponential increase. This enduring rate makes it unnecessary to invoke environmental change to explain the post-Paleozoic increase of marine diversity.Because of the resilience of intrinsic rates, an empirically based simulation that entails intervals of exponential increase for the Paleozoic and Modern Faunas, punctuated by mass extinctions, yields a pattern that is remarkably similar to the empirical pattern. It follows that marine animal genera and species will continue to diversify exponentially long into the future, barring disruption of the marine ecosystem by human-induced or natural environmental changes.

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Lopatka, Alex. « Climate change drives extinction—and always has ». Physics Today 77, n^o 5 (1 mai 2024) : 15–16. http://dx.doi.org/10.1063/pt.ojbx.srdb.

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Jablonski, David. « Micro- and macroevolution : Scale and hierarchy in evolutionary biology and paleobiology ». Paleobiology 26, S4 (2000) : 15–52. http://dx.doi.org/10.1017/s0094837300026877.

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The study of evolution has increasingly incorporated considerations of history, scale, and hierarchy, in terms of both the origin of variation and the sorting of that variation. Although the macroevolutionary exploration of developmental genetics has just begun, considerable progress has been made in understanding the origin of evolutionary novelty in terms of the potential for coordinated morphological change and the potential for imposing uneven probabilities on different evolutionary directions. Global or whole-organism heterochrony, local heterochrony (affecting single structures, regions, or organ systems) and heterotopies (changes in the location of developmental events), and epigenetic mechanisms (which help to integrate the developing parts of an organism into a functional whole) together contribute to profound nonlinearities between genetic and morphologic change, by permitting the generation and accommodation of evolutionary novelties without pervasive, coordinated genetic changes; the limits of these developmental processes are poorly understood, however. The discordance across hierarchical levels in the production of evolutionary novelties through time, and among latitudes and environments, is an intriguing paleontological pattern whose explanation is controversial, in part because separating effects of genetics and ecology has proven difficult. At finer scales, species in the fossil record tend to be static over geologic time, although this stasis—to which there are gradualistic exceptions—generally appears to be underlain by extensive, nondirectional change rather than absolute invariance. Only a few studies have met the necessary protocols for the analysis of evolutionary tempo and mode at the species level, and so the distribution of evolutionary patterns among clades, environments, and modes of life remains poorly understood. Sorting among taxa is widely accepted in principle as an evolutionary mechanism, but detailed analyses are scarce; if geographic range or population density can be treated as traits above the organismic level, then the paleontological and mac̀roecological literature abounds in potential raw material for such analyses. Even if taxon sorting operates on traits that are not emergent at the species level, the differential speciation and extinction rates can shape large-scale evolutionary patterns in ways that are not simple extrapolations from short-term evolution at the organismal level. Changes in origination and extinction rates can evidently be mediated by interactions with other clades, although such interactions need to be studied in a geographically explicit fashion before the relative roles of biotic and physical factors can be assessed. Incumbency effects are important at many scales, with the most dramatic manifestation being the postextinction diversifications that follow the removal of incumbents. However, mass extinctions are evolutionarily important not only for the removal of dominant taxa, which can occur according to rules that differ from those operating during times of lower extinction intensity, but also for the dramatic diversifications that follow upon the removal or depletion of incumbents. Mass extinctions do not entirely reset the evolutionary clock, so survivors can exhibit unbroken evolutionary continuity, trends that suffer setbacks but then resume, or failure to participate in the recovery.

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Nunn, Charles L., Alexander Q. Vining, Debapriyo Chakraborty, Michael H. Reiskind et Hillary S. Young. « Effects of host extinction and vector preferences on vector-borne disease risk in phylogenetically structured host-hector communities ». PLOS ONE 16, n^o 8 (23 août 2021) : e0256456. http://dx.doi.org/10.1371/journal.pone.0256456.

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Anthropogenic disturbance impacts the phylogenetic composition and diversity of ecological communities. While changes in diversity are known to dramatically change species interactions and alter disease dynamics, the effects of phylogenetic changes in host and vector communities on disease have been relatively poorly studied. Using a theoretical model, we investigated how phylogeny and extinction influence network structural characteristics relevant to disease transmission in disturbed environments. We modelled a multi-host, multi-vector community as a bipartite ecological network, where nodes represent host and vector species and edges represent connections among them through vector feeding, and we simulated vector preferences and threat status on host and parasite phylogenies. We then simulated loss of hosts, including phylogenetically clustered losses, to investigate how extinction influences network structure. We compared effects of phylogeny and extinction to those of host specificity, which we predicted to strongly increase network modularity and reduce disease prevalence. The simulations revealed that extinction often increased modularity, with higher modularity as species loss increased, although not as much as increasing host specificity did. These results suggest that extinction itself, all else being equal, may reduce disease prevalence in disturbed communities. However, in real communities, systematic patterns in species loss (e.g. favoring high competence species) or changes in abundance may counteract these effects. Unexpectedly, we found that effects of phylogenetic signal in host and vector traits were relatively weak, and only important when phylogenetic signal of host and vector traits were similar, or when these traits both varied.

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Rocha-Ortega, Maya, Pilar Rodríguez, Jason Bried, John Abbott et Alex Córdoba-Aguilar. « Why do bugs perish ? Range size and local vulnerability traits as surrogates of Odonata extinction risk ». Proceedings of the Royal Society B : Biological Sciences 287, n^o 1924 (avril 2020) : 20192645. http://dx.doi.org/10.1098/rspb.2019.2645.

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Despite claims of an insect decline worldwide, our understanding of extinction risk in insects is incomplete. Using bionomic data of all odonate (603 dragonflies and damselflies) North American species, we assessed (i) regional extinction risk and whether this is related to local extirpation; (ii) whether these two patterns are similar altitudinally and latitudinally; and (iii) the areas of conservation concern. We used geographic range size as a predictor of regional extinction risk and body size, thermal limits and habitat association as predictors of local extirpation. We found that (i) greater regional extinction risk is related to narrow thermal limits, lotic habitat use and large body size (this in damselflies but not dragonflies); (ii) southern species are more climate tolerant but with more limited geographic range size than northern species; and (iii) two priority areas for odonate conservation are the cold temperate to sub-boreal northeastern USA and the transversal neo-volcanic system. Our approach can be used to estimate insect extinction risk as it compensates for the lack of abundance data.

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Lundgren, Erick J., Daniel Ramp, John Rowan, Owen Middleton, Simon D. Schowanek, Oscar Sanisidro, Scott P. Carroll et al. « Introduced herbivores restore Late Pleistocene ecological functions ». Proceedings of the National Academy of Sciences 117, n^o 14 (23 mars 2020) : 7871–78. http://dx.doi.org/10.1073/pnas.1915769117.

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Large-bodied mammalian herbivores dominated Earth’s terrestrial ecosystems for several million years before undergoing substantial extinctions and declines during the Late Pleistocene (LP) due to prehistoric human impacts. The decline of large herbivores led to widespread ecological changes due to the loss of their ecological functions, as driven by their unique combinations of traits. However, recently, humans have significantly increased herbivore species richness through introductions in many parts of the world, potentially counteracting LP losses. Here, we assessed the extent to which introduced herbivore species restore lost—or contribute novel—functions relative to preextinction LP assemblages. We constructed multidimensional trait spaces using a trait database for all extant and extinct mammalian herbivores ≥10 kg known from the earliest LP (∼130,000 ybp) to the present day. Extinction-driven contractions of LP trait space have been offset through introductions by ∼39% globally. Analysis of trait space overlap reveals that assemblages with introduced species are overall more similar to those of the LP than native-only assemblages. This is because 64% of introduced species are more similar to extinct rather than extant species within their respective continents. Many introduced herbivores restore trait combinations that have the capacity to influence ecosystem processes, such as wildfire and shrub expansion in drylands. Although introduced species have long been a source of contention, our findings indicate that they may, in part, restore ecological functions reflective of the past several million years before widespread human-driven extinctions.

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Miles, Donald B. « Can Morphology Predict the Conservation Status of Iguanian Lizards ? » Integrative and Comparative Biology 60, n^o 2 (19 juin 2020) : 535–48. http://dx.doi.org/10.1093/icb/icaa074.

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Synopsis The integrity of regional and local biological diversity is under siege as a result of multiple anthropogenic threats. The conversion of habitats, such as rain forests, into agricultural ecosystems, reduces the area available to support species populations. Rising temperatures and altered rainfall patterns lead to additional challenges for species. The ability of conservation biologists to ascertain the threats to a species requires data on changes in distribution, abundance, life history, and ecology. The International Union for the Conservation of Nature (IUCN) uses these data to appraise the extinction risk for a species. However, many species remain data deficient (DD) or unassessed. Here, I use 14 morphological traits related to locomotor function, habitat, and feeding to predict the threat status of over 400 species of lizards in the infraorder Iguania. Morphological traits are an ideal proxy for making inferences about a species’ risk of extinction. Patterns of morphological covariation have a known association with habitat use, foraging behavior, and physiological performance across multiple taxa. Results from phylogenetic general linear models revealed that limb lengths as well as head characters predicted extinction risk. In addition, I used an artificial neural network (ANN) technique to generate a classification function based on the morphological traits of species with an assigned IUCN threat status. The network approach identified eight morphological traits as predictors of extinction risk, which included head and limb characters. The best supported model had a classification accuracy of 87.4%. Moreover, the ANN model predicted >18% of DD/not assessed species were at risk of extinction. The predicted assessments were supported by other sources of threat status, for example, Convention on International Trade in Endangered Species appendices. Because of the functional link between morphology, performance, and ecology, an ecomorphological approach may be a useful tool for rapid assessment of DD or poorly known species.

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Leimar, Olof, et Ulf Norberg. « Metapopulation Extinction and Genetic Variation in Dispersal-Related Traits ». Oikos 80, n^o 3 (décembre 1997) : 448. http://dx.doi.org/10.2307/3546617.

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Iwasa, Yoh. « Extinction risk of natural populations and phenotypic traits evolution ». Researches on Population Ecology 40, n^o 3 (décembre 1998) : 257–58. http://dx.doi.org/10.1007/bf02763456.

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Hernández-Yáñez, Haydée, Su Yeon Kim et Judy P. Che-Castaldo. « Demographic and life history traits explain patterns in species vulnerability to extinction ». PLOS ONE 17, n^o 2 (23 février 2022) : e0263504. http://dx.doi.org/10.1371/journal.pone.0263504.

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As ecosystems face disruption of community dynamics and habitat loss, the idea of determining ahead of time which species can become extinct is an important subject in conservation biology. A species’ vulnerability to extinction is dependent upon both intrinsic (life-history strategies, genetics) and extrinsic factors (environment, anthropogenic threats). Studies linking intrinsic traits to extinction risk have shown variable results, and to our knowledge, there has not been a systematic analysis looking at how demographic patterns in stage-specific survival and reproductive rates correlate to extinction risk. We used matrix projection models from the COMPADRE and COMADRE matrix databases and IUCN Red List status as our proxy of extinction risk to investigate if some demographic patterns are more vulnerable to extinction than others. We obtained data on demographic rates, phylogeny, and IUCN status for 159 species of herbaceous plants, trees, mammals, and birds. We calculated 14 demographic metrics related to different aspects of life history and elasticity values and analyzed whether they differ based on IUCN categories using conditional random forest analysis and phylogenetic generalized least square regressions. We mapped all species within the database, both with IUCN assessment and without, and overlaid them with biodiversity hotspots to investigate if there is bias within the assessed species and how many of the non-assessed species could use the demographic information recorded in COMPADRE and COMADRE for future IUCN assessments. We found that herbaceous perennials are more vulnerable when they mature early and have high juvenile survival rates; birds are more vulnerable with high progressive growth and reproduction; mammals are more vulnerable when they have longer generation times. These patterns may be used to assess relative vulnerability across species when lacking abundance or trend data.

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Arbuckle, Kevin, et Michael P. Speed. « Antipredator defenses predict diversification rates ». Proceedings of the National Academy of Sciences 112, n^o 44 (19 octobre 2015) : 13597–602. http://dx.doi.org/10.1073/pnas.1509811112.

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The “escape-and-radiate” hypothesis predicts that antipredator defenses facilitate adaptive radiations by enabling escape from constraints of predation, diversified habitat use, and subsequently speciation. Animals have evolved diverse strategies to reduce the direct costs of predation, including cryptic coloration and behavior, chemical defenses, mimicry, and advertisement of unprofitability (conspicuous warning coloration). Whereas the survival consequences of these alternative defenses for individuals are well-studied, little attention has been given to the macroevolutionary consequences of alternative forms of defense. Here we show, using amphibians as the first, to our knowledge, large-scale empirical test in animals, that there are important macroevolutionary consequences of alternative defenses. However, the escape-and-radiate hypothesis does not adequately describe them, due to its exclusive focus on speciation. We examined how rates of speciation and extinction vary across defensive traits throughout amphibians. Lineages that use chemical defenses show higher rates of speciation as predicted by escape-and-radiate but also show higher rates of extinction compared with those without chemical defense. The effect of chemical defense is a net reduction in diversification compared with lineages without chemical defense. In contrast, acquisition of conspicuous coloration (often used as warning signals or in mimicry) is associated with heightened speciation rates but unchanged extinction rates. We conclude that predictions based on the escape-and-radiate hypothesis must incorporate the effect of traits on both speciation and extinction, which is rarely considered in such studies. Our results also suggest that knowledge of defensive traits could have a bearing on the predictability of extinction, perhaps especially important in globally threatened taxa such as amphibians.

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Kiessling, Wolfgang, et Ádám T. Kocsis. « Adding fossil occupancy trajectories to the assessment of modern extinction risk ». Biology Letters 12, n^o 10 (octobre 2016) : 20150813. http://dx.doi.org/10.1098/rsbl.2015.0813.

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Besides helping to identify species traits that are commonly linked to extinction risk, the fossil record may also be directly relevant for assessing the extinction risk of extant species. Standing geographical distribution or occupancy is a strong predictor of both recent and past extinction risk, but the role of changes in occupancy is less widely assessed. Here we demonstrate, based on the Cenozoic fossil record of marine species, that both occupancy and its temporal trajectory are significant determinants of risk. Based on extinct species we develop a model on the additive and interacting effects of occupancy and its temporal changes on extinction risk. We use this model to predict extinction risk of extant species. The predictions suggest a moderate risk for marine species on average. However, some species seem to be on a long-term decline and potentially at a latent extinction risk, which is not considered in current risk assessments.

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Yamamichi, Masato, et Stephen P. Ellner. « Antagonistic coevolution between quantitative and Mendelian traits ». Proceedings of the Royal Society B : Biological Sciences 283, n^o 1827 (30 mars 2016) : 20152926. http://dx.doi.org/10.1098/rspb.2015.2926.

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Coevolution is relentlessly creating and maintaining biodiversity and therefore has been a central topic in evolutionary biology. Previous theoretical studies have mostly considered coevolution between genetically symmetric traits (i.e. coevolution between two continuous quantitative traits or two discrete Mendelian traits). However, recent empirical evidence indicates that coevolution can occur between genetically asymmetric traits (e.g. between quantitative and Mendelian traits). We examine consequences of antagonistic coevolution mediated by a quantitative predator trait and a Mendelian prey trait, such that predation is more intense with decreased phenotypic distance between their traits (phenotype matching). This antagonistic coevolution produces a complex pattern of bifurcations with bistability (initial state dependence) in a two-dimensional model for trait coevolution. Furthermore, with eco-evolutionary dynamics (so that the trait evolution affects predator–prey population dynamics), we find that coevolution can cause rich dynamics including anti-phase cycles, in-phase cycles, chaotic dynamics and deterministic predator extinction. Predator extinction is more likely to occur when the prey trait exhibits complete dominance rather than semidominance and when the predator trait evolves very rapidly. Our study illustrates how recognizing the genetic architectures of interacting ecological traits can be essential for understanding the population and evolutionary dynamics of coevolving species.

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Bender, M. G., S. R. Floeter, F. P. Mayer, D. A. Vila-Nova, G. O. Longo, N. Hanazaki, A. Carvalho-Filho et C. E. L. Ferreira. « Biological attributes and major threats as predictors of the vulnerability of species : a case study with Brazilian reef fishes ». Oryx 47, n^o 2 (avril 2013) : 259–65. http://dx.doi.org/10.1017/s003060531100144x.

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AbstractGlobal biodiversity declines and increasing rates of extinction necessitate the assessment and prediction of the vulnerability of species to extinction. Here, we examine the relationships between conservation status and ecological traits of reef fish species of the Brazilian biogeographical province. We used binomial tests and a logistic regression to address two questions. Do biological attributes differ between threatened and non-threatened fishes? Which combination of traits and impacts exerts greater influence on species threat status? Of the 559 species, 36 are categorized as threatened (compiled from global, national and local Red Lists). Three species are categorized as Critically Endangered, seven as Endangered and 26 as Vulnerable. Our analyses revealed that Elasmobranchii, sex-changing bony fishes and endemic species are the most vulnerable reef fishes in Brazilian waters. Body size and trophic category were identified as good predictors of the vulnerability of a species to extinction. Small-bodied species that are exploited by the ornamental trade and have complex reproductive strategies are also of concern. Such combinations of attributes could be of value in predicting which reef fish species elsewhere have a high risk of extinction.

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Fattorini, Simone. « Species ecological preferences predict extinction risk in urban tenebrionid beetle guilds ». Animal Biology 63, n^o 1 (2013) : 93–106. http://dx.doi.org/10.1163/15707563-00002396.

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A number of studies have attempted to investigate which species traits influence species proneness to extinction in vertebrates. By contrast, studies involving insects are scarce, because of difficulties in obtaining complex assessments of species extinction risk and measures of species traits. In this paper, a simple (binary) codification based on literature data and field observations was used to determine the importance of various traits (notably ecological preferences) in determining species vulnerability of the tenebrionid beetles inhabiting urban Rome (Italy). Vulnerability scores were calculated from measures of geographical, habitat and population rarity. Vulnerable species were distributed with similar proportions among different tenebrionid guilds, which suggests that conservation programs in urban ecosystems should be more addressed to the development of species-oriented actions than to the identification of priority ‘habitats’. Species traits accurately predicted species assignment to vulnerability classes, with some traits being particularly important in determining species vulnerability. Species associated with ruins and cellars, and which are typically fairly common in Rome, tend to be moderately or middle vulnerable. The identification of important sites for these species and definition of measures for population management would be useful strategies to preserve them.

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DEBABECHE, Kaouther, Abdelaaziz BOUAFIA et Abdelaali BENCHEIKH. « Phenotypic diversity of date palm varieties (Phoenix dactylifera L.) from southwest Algeria estimated by fruit characteristics ». Acta agriculturae Slovenica 119, n^o 1 (28 avril 2023) : 1. http://dx.doi.org/10.14720/aas.2023.119.1.2611.

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This study aimed to identify the genetic diversity of date palm (Phoenix dactylifera L.) in the southwest of Algeria (wilaya of Adrar), as part of the Algerian date palm varieties conservation. The morphological characterization was adopted in terms of quality and quantity of 26 varieties. The main results showed a considerable genetic diversity of date palms in this agricultural territory. 7 cultivars counted in danger of extinction. The cluster analysis brought out significant differences between qualitative and quantitative traits. However, the cultivars of ‘Deglet Talmine’, ‘Maatouk’, and ‘Timidouele’ produced dates of high quantitative traits, however, of different qualitative traits. Also, some relationships were observed within clusters for other varieties. A variety named ‘Khalt’ was able to produce dates better than many cultivars. This work would help to know the focal traits of the plant genetic resources of date palm and preserve that are in extinction.

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DEBABECHE, Kaouther, Abdelaaziz BOUAFIA et Abdelaali BENCHEIKH. « Phenotypic diversity of date palm varieties (Phoenix dactylifera L.) from southwest Algeria estimated by fruit characteristics ». Acta agriculturae Slovenica 119, n^o 1 (28 avril 2023) : 1. http://dx.doi.org/10.14720/aas.2023.119.1.2661.

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This study aimed to identify the genetic diversity of date palm (Phoenix dactylifera L.) in the southwest of Algeria (wilaya of Adrar), as part of the Algerian date palm varieties conservation. The morphological characterization was adopted in terms of quality and quantity of 26 varieties. The main results showed a considerable genetic diversity of date palms in this agricultural territory. 7 cultivars counted in danger of extinction. The cluster analysis brought out significant differences between qualitative and quantitative traits. However, the cultivars of ‘Deglet Talmine’, ‘Maatouk’, and ‘Timidouele’ produced dates of high quantitative traits, however, of different qualitative traits. Also, some relationships were observed within clusters for other varieties. A variety named ‘Khalt’ was able to produce dates better than many cultivars. This work would help to know the focal traits of the plant genetic resources of date palm and preserve that are in extinction.

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Powell, Matthew G., et Johnryan MacGregor. « A geographic test of species selection using planktonic foraminifera during the Cretaceous/Paleogene mass extinction ». Paleobiology 37, n^o 3 (2011) : 426–37. http://dx.doi.org/10.1666/10010.1.

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Species selection has received a great deal of theoretical attention but it has rarely been empirically tested. It is important to determine the level of selection that operated during a particular extinction event because it can help distinguish between traits that were actually responsible for extinction and those that were merely correlated with it. Here, we present a test that can help distinguish between organismal and species-level selection, which we demonstrate using the high-resolution fossil record of planktonic foraminifera species recorded in deep-sea sediment cores. Our test examines the fate of survivors and victims during the Cretaceous/Paleogene (K/Pg) mass extinction within single geographic regions, where all individuals experience the same selection pressures. Selection at the organismal level implies that individual members of surviving species are more fit than those of victimized species, and therefore should be more likely to survive in affected areas; conversely, selection at the species level implies individuals will suffer equally within an affected area. We find that survivors of the mass extinction suffered very high extirpation rates in cores where the overall extinction rate was high, indicating that individual members of the surviving species were generally no more fit than individual members of extinct species. Rather, these species were able to survive because they possessed advantageous species-level traits, such as larger geographic ranges and greater abundances than victimized species. This geographic pattern of extirpation suggests that selection operated at the species, rather than organismal, level during the K/Pg mass extinction of planktonic foraminifera.

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van Zuijlen, Kristel, Irene Bisang, Michael P. Nobis et Ariel Bergamini. « Extinction risk of European bryophytes predicted by bioclimate and traits ». Biological Conservation 293 (mai 2024) : 110584. http://dx.doi.org/10.1016/j.biocon.2024.110584.

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Thompson, Jeffrey R., et William I. Ausich. « Testing for escalation in Lower Mississippian camerate crinoids ». Paleobiology 41, n^o 1 (janvier 2015) : 89–107. http://dx.doi.org/10.1017/pab.2014.6.

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AbstractCrinoids were relatively unaffected by the end-Devonian Hangenberg mass extinction event. Major clades of Devonian durophagous fishes suffered significant extinctions, however, and the dominant surviving clades were biting or nipping predators. In part as a response to the Hangenberg event, early Mississippian crinoids underwent an adaptive radiation, while fish clades with a shell-crushing durophagous strategy diversified. Durophagous predators are inferred to have been more effective predators on camerate crinoids; and it is hypothesized, following the predictions of escalation, that through the early Mississippian, camerate crinoids evolved more effective anti-predatory strategies in response. We test this hypothesis of escalation by examining the changes in spinosity and plate convexity among camerate crinoids throughout this interval. A new method was formulated to test for an increase in convexity of the tegmen plates. Traits inAgaricocrinus,Aorocrinus, andDorycrinus(Family Coelocrinidae) were tested for congruence to the escalation hypothesis, and results were mixed. Convexity of tegmen plates inAgaricocrinus, spine length/calyx diameter inAorocrinus, calyx size inAorocrinus, central spine length inDorycrinus, and spine width inDorycrinusdid not have size increase trends supporting escalation. Rather than an increase in convexity, the variance of convexity inAgaricocrinustegmen plates narrowed, which could reflect an optimum. Alternatively, morphological change consistent with the escalation hypothesis occurred in calyx size ofAgaricocrinusand in lateral spine length and calyx size inDorycrinus. Furthermore, central and lateral spine length, parameters of the spine width, and size trends support escalation whenAorocrinusandDorycrinusare treated as a lineage. Thus, inferred escalation acted on traits differently within a single lineage and was relevant for both speciation and the diversification of a new genus.

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Welch, Jessica, et Jeremy Beaulieu. « Predicting Extinction Risk for Data Deficient Bats ». Diversity 10, n^o 3 (13 juillet 2018) : 63. http://dx.doi.org/10.3390/d10030063.

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Conservation biology aims to identify species most at risk of extinction and to understand factors that forecast species vulnerability. The International Union for Conservation of Nature (IUCN) Red List is a leading source for extinction risk data of species globally, however, many potentially at risk species are not assessed by the IUCN owing to inadequate data. Of the approximately 1150 bat species (Chiroptera) recognized by the IUCN, 17 percent are categorized as Data Deficient. Here, we show that large trait databases in combination with a comprehensive phylogeny can identify which traits are important for assessing extinction risk in bats. Using phylogenetic logistic regressions, we show that geographic range and island endemism are the strongest correlates of binary extinction risk. We also show that simulations using two models that trade-off between data complexity and data coverage provide similar estimates of extinction risk for species that have received a Red List assessment. We then use our model parameters to provide quantitative predictions of extinction risk for 60 species that have not received risk assessments by the IUCN. Our model suggests that at least 20 bat species should be treated as threatened by extinction. In combination with expert knowledge, our results can be used as a quick, first-pass prioritization for conservation action.

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Solé, Ricard V., Bernat Corominas-Murtra et Jordi Fortuny. « Diversity, competition, extinction : the ecophysics of language change ». Journal of The Royal Society Interface 7, n^o 53 (30 juin 2010) : 1647–64. http://dx.doi.org/10.1098/rsif.2010.0110.

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As indicated early by Charles Darwin, languages behave and change very much like living species. They display high diversity, differentiate in space and time, emerge and disappear. A large body of literature has explored the role of information exchanges and communicative constraints in groups of agents under selective scenarios. These models have been very helpful in providing a rationale on how complex forms of communication emerge under evolutionary pressures. However, other patterns of large-scale organization can be described using mathematical methods ignoring communicative traits. These approaches consider shorter time scales and have been developed by exploiting both theoretical ecology and statistical physics methods. The models are reviewed here and include extinction, invasion, origination, spatial organization, coexistence and diversity as key concepts and are very simple in their defining rules. Such simplicity is used in order to catch the most fundamental laws of organization and those universal ingredients responsible for qualitative traits. The similarities between observed and predicted patterns indicate that an ecological theory of language is emerging, supporting (on a quantitative basis) its ecological nature, although key differences are also present. Here, we critically review some recent advances and outline their implications and limitations as well as highlight problems for future research.

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Reif, Jiří, et Klára Štěpánková. « Global analysis of threat status reveals higher extinction risk in tropical than in temperate bird sister species ». European Journal of Ecology 2, n^o 1 (1 juin 2016) : 21–34. http://dx.doi.org/10.1515/eje-2016-0003.

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Abstract Given increasing pressures upon biodiversity, identification of species’ traits related to elevated extinction risk is useful for more efficient allocation of limited resources for nature conservation. Despite its need, such a global analysis was lacking in the case of birds. Therefore, we performed this exercise for avian sister species using information about their global extinction risk from IUCN Red List. We focused on 113 pairs of sister species, each containing a threatened and an unthreatened species to factor out the effects of common evolutionary history on the revealed relationship. We collected data on five traits with expected relationships to species’ extinction risk based on previous studies performed at regional or national levels: breeding habitat (recognizing forest, grassland, wetland and oceanic species), latitudinal range position (temperate and tropics species), migration strategy (migratory and resident species), diet (carnivorous, insectivorous, herbivorous and omnivorous species) and body mass. We related the extinction risk using IUCN threat level categories to species’ traits using generalised linear mixed effects models expecting lower risk for forest, temperate, omnivorous and smaller-bodied species. Our expectation was confirmed only in the case of latitudinal range position, as we revealed higher threat level for tropical than for temperate species. This relationship was robust to different methods of threat level expression and cannot be explained by a simple association of high bird species richness with the tropical zone. Instead, it seems that tropical species are more threatened because of their intrinsic characteristics such as slow life histories, adaptations to stable environments and small geographic ranges. These characteristics are obviously disadvantageous in conditions of current human-induced environmental perturbations. Moreover, given the absence of habitat effects, our study indicates that such perturbations act across different tropical environments. Therefore, disproportionally higher conservation effort in the tropics compared to the temperate zone is urgently needed.

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Dalsgaard, Bo, Jonathan D. Kennedy, Benno I. Simmons, Andrea C. Baquero, Ana M. Martín González, Allan Timmermann, Pietro K. Maruyama et al. « Trait evolution, resource specialization and vulnerability to plant extinctions among Antillean hummingbirds ». Proceedings of the Royal Society B : Biological Sciences 285, n^o 1875 (21 mars 2018) : 20172754. http://dx.doi.org/10.1098/rspb.2017.2754.

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Species traits are thought to predict feeding specialization and the vulnerability of a species to extinctions of interaction partners, but the context in which a species evolved and currently inhabits may also matter. Notably, the predictive power of traits may require that traits evolved to fit interaction partners. Furthermore, local abiotic and biotic conditions may be important. On islands, for instance, specialized and vulnerable species are predicted to be found mainly in mountains, whereas species in lowlands should be generalized and less vulnerable. We evaluated these predictions for hummingbirds and their nectar-food plants on Antillean islands. Our results suggest that the rates of hummingbird trait divergence were higher among ancestral mainland forms before the colonization of the Antilles. In correspondence with the limited trait evolution that occurred within the Antilles, local abiotic and biotic conditions—not species traits—correlate with hummingbird resource specialization and the vulnerability of hummingbirds to extinctions of their floral resources. Specifically, hummingbirds were more specialized and vulnerable in conditions with high topographical complexity, high rainfall, low temperatures and high floral resource richness, which characterize the Antillean Mountains. These findings show that resource specialization and species vulnerability to extinctions of interaction partners are highly context-dependent.

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Chichorro, Filipe, Aino Juslén et Pedro Cardoso. « A review of the relation between species traits and extinction risk ». Biological Conservation 237 (septembre 2019) : 220–29. http://dx.doi.org/10.1016/j.biocon.2019.07.001.

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FISHER, DIANA O., et SIMON P. BLOMBERG. « Inferring Extinction of Mammals from Sighting Records, Threats, and Biological Traits ». Conservation Biology 26, n^o 1 (2 décembre 2011) : 57–67. http://dx.doi.org/10.1111/j.1523-1739.2011.01797.x.

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Tobias, Joseph A., et Alex L. Pigot. « Integrating behaviour and ecology into global biodiversity conservation strategies ». Philosophical Transactions of the Royal Society B : Biological Sciences 374, n^o 1781 (29 juillet 2019) : 20190012. http://dx.doi.org/10.1098/rstb.2019.0012.

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Insights into animal behaviour play an increasingly central role in species-focused conservation practice. However, progress towards incorporating behaviour into regional or global conservation strategies has been more limited, not least because standardized datasets of behavioural traits are generally lacking at wider taxonomic or spatial scales. Here we make use of the recent expansion of global datasets for birds to assess the prospects for including behavioural traits in systematic conservation priority-setting and monitoring programmes. Using International Union for Conservation of Nature Red List classifications for more than 9500 bird species, we show that the incidence of threat can vary substantially across different behavioural categories, and that some types of behaviour—including particular foraging, mating and migration strategies—are significantly more threatened than others. The link between behavioural traits and extinction risk is partly driven by correlations with well-established geographical and ecological factors (e.g. range size, body mass, human population pressure), but our models also reveal that behaviour modifies the effect of these factors, helping to explain broad-scale patterns of extinction risk. Overall, these results suggest that a multi-species approach at the scale of communities, continents and ecosystems can be used to identify and monitor threatened behaviours, and to flag up cases of latent extinction risk, where threatened status may currently be underestimated. Our findings also highlight the importance of comprehensive standardized descriptive data for ecological and behavioural traits, and point the way towards deeper integration of behaviour into quantitative conservation assessments. This article is part of the theme issue ‘Linking behaviour to dynamics of populations and communities: application of novel approaches in behavioural ecology to conservation’.

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Barrett, J., et J. L. Armony. « Influence of trait anxiety on brain activity during the acquisition and extinction of aversive conditioning ». Psychological Medicine 39, n^o 2 (9 mai 2008) : 255–65. http://dx.doi.org/10.1017/s0033291708003516.

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BackgroundWe examined how individual differences in trait anxiety (TA) influence the neural responses associated with the acquisition and extinction of anticipatory anxiety elicited through a context conditioning paradigm, with particular focus on the amygdala and the subgenual anterior cingulate cortex (sgACC).MethodDuring two sessions of echo-planar functional magnetic resonance imaging (fMRI), 18 healthy volunteers completed a decision-making task with two randomly alternating 28-s to 32-s background screen colour blocks. One of the colours was associated with the presentation of an aversive noise (CTX+) and the other colour was ‘safe’ (CTX−). In the first session (Acquisition), 33% of CTX+ colour blocks were paired with noise and in the second session (Extinction) no noise was presented.ResultsThe amygdala displayed an increased response to CTX+ compared to CTX− colour blocks during the Acquisition and Extinction sessions and the ACC displayed an increased response to CTX+ compared to CTX− colour blocks during Extinction only. In addition, a greater conditioned response (CTX+ minus CTX−) was observed in the ACC when comparing the Extinction and Acquisition sessions. Correlation analyses further showed that higher levels of TA were associated with a higher conditioned response in the amygdala during Extinction as well as a greater differential conditioned response (i.e. Extinction>Acquisition) in the ACC.ConclusionsOur results support the idea that individuals with high levels of anxiety-relevant traits and vulnerable to developing an anxiety disorder display a more resilient anxiety response during extinction that is characterized by hyper-responsivity in the amygdala.

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Norris, Richard D., et William A. Berggren. « Recovery from mass extinction in pelagic biotas ». Paleontological Society Special Publications 6 (1992) : 223. http://dx.doi.org/10.1017/s2475262200007838.

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Mass extinctions profoundly affect patterns of diversification and skeletal innovation in the succeeding radiation. For instance, promising adaptations may be removed permitting traits of the few survivors to proliferate. Consequently, patterns of survivorship could control directions of radiation following the extinction event. Alternatively, selection during radiation may be quite different from extinction conditions. The founders may be quickly superseded by taxa with wholely new innovations that are built upon, but are distinct from, the founding morphologies.Planktic foraminifera nearly became extinct at the end of the Cretaceous. Of the two or three lineages that survived, perhaps only one founded the bulk of the Paleocene radiation of Globigerinacea. In addition, there was little habitat diversification within the surviving lineages. Nearly all the morphological and ecological innovations occur in a single clade that diverged rapidly from the ancestral stock.Neither of the best known surviving lineages diversified much after the Cretaceous. Hedbergella monmouthensis is the ancestor of Danian Globanomalina archaeocompressa. The two taxa are nearly identical in both morphology and in isotopic signature. Significantly, the globanomalinids displayed very little diversification, like their Cretaceous ancestors before them. Instead, species were replaced one after another in an anagenetic trend and consistently occupied a moderately deep-water habitat. Similarly, triserial Guembelitria gave rise to only a modest radiation of biserial species in the earliest Danian primarilly within near surface water habitats.Cladistic analysis suggests that the major part of the Cenozoic radiation was founded by one or two Cretaceous taxa. Most Danian trochospiral species abruptly radiated into two main stocks in the earliest Danian. All of them are probably derived from Hedbergella, but they rapidly became morphologically differentiated from this Cretaceous survivor. Alternatively, many of the features of the Danian species may have been inherited from another Cretaceous survivor–possibly a species of Rugoglobigerina–as suggested by comparative studies of early ontogeny. In either case, the group split rapidly into two main lineages. One, rooted in non-spinose ‘Morozovella’ taurica, led to the major diversification of the muricate-walled morozovellids. Isotopic data suggest this lineage spread from a moderately deep water habitat into the near-surface waters where the major diversification occurred. The other lineage developed spinose wall texture and gave rise to the diverse subbotinid radiation. Stable isotopic data suggests the subbotinids grew consistently in the coldest and presumably deepest waters. Their spinose wall texture suggests they were at least partly carnivorous, by analogy with living spinose taxa.These patterns of morphological and ecological diversification suggest that the immediate survivors did not radiate markedly but retained the evolutionary rates and habitats of their Cretaceous ancestors. Most of the radiation occurred in a clade whose innovations evolved during the Danian, rather than simply retooling traits of their founder. Likewise, the radiation occurred principally in surface and deep water habitats, both largely vacated by the extinction event. The intermediate depth habitats were continuously occupied by the persistent hedbergellid-globanomalinid lineage. Their habitat was not invaded by other radiating clades. Evidently, survival alone does not confer the capacity for subsequent diversification upon a founding species. Innovation seems to be the key to dominance rather than mere persistence through an episode of heightened extinction.

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Di Marco, Moreno, Ben Collen, Carlo Rondinini et Georgina M. Mace. « Historical drivers of extinction risk : using past evidence to direct future monitoring ». Proceedings of the Royal Society B : Biological Sciences 282, n^o 1813 (22 août 2015) : 20150928. http://dx.doi.org/10.1098/rspb.2015.0928.

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Global commitments to halt biodiversity decline mean that it is essential to monitor species' extinction risk. However, the work required to assess extinction risk is intensive. We demonstrate an alternative approach to monitoring extinction risk, based on the response of species to external conditions. Using retrospective International Union for Conservation of Nature Red List assessments, we classify transitions in the extinction risk of 497 mammalian carnivores and ungulates between 1975 and 2013. Species that moved to lower Red List categories, or remained Least Concern, were classified as ‘lower risk'; species that stayed in a threatened category, or moved to a higher category of risk, were classified as ‘higher risk'. Twenty-four predictor variables were used to predict transitions, including intrinsic traits (species biology) and external conditions (human pressure, distribution state and conservation interventions). The model correctly classified up to 90% of all transitions and revealed complex interactions between variables, such as protected areas (PAs) versus human impact. The most important predictors were: past extinction risk, PA extent, geographical range size, body size, taxonomic family and human impact. Our results suggest that monitoring a targeted set of metrics would efficiently identify species facing a higher risk, and could guide the allocation of resources between monitoring species' extinction risk and monitoring external conditions.

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Lee, Tien Ming, et Walter Jetz. « Unravelling the structure of species extinction risk for predictive conservation science ». Proceedings of the Royal Society B : Biological Sciences 278, n^o 1710 (13 octobre 2010) : 1329–38. http://dx.doi.org/10.1098/rspb.2010.1877.

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Extinction risk varies across species and space owing to the combined and interactive effects of ecology/life history and geography. For predictive conservation science to be effective, large datasets and integrative models that quantify the relative importance of potential factors and separate rapidly changing from relatively static threat drivers are urgently required. Here, we integrate and map in space the relative and joint effects of key correlates of The International Union for Conservation of Nature-assessed extinction risk for 8700 living birds. Extinction risk varies significantly with species' broad-scale environmental niche, geographical range size, and life-history and ecological traits such as body size, developmental mode, primary diet and foraging height. Even at this broad scale, simple quantifications of past human encroachment across species' ranges emerge as key in predicting extinction risk, supporting the use of land-cover change projections for estimating future threat in an integrative setting. A final joint model explains much of the interspecific variation in extinction risk and provides a remarkably strong prediction of its observed global geography. Our approach unravels the species-level structure underlying geographical gradients in extinction risk and offers a means of disentangling static from changing components of current and future threat. This reconciliation of intrinsic and extrinsic, and of past and future extinction risk factors may offer a critical step towards a more continuous, forward-looking assessment of species' threat status based on geographically explicit environmental change projections, potentially advancing global predictive conservation science.

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