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1.
Greet Van de Vyver 《Dialectical Anthropology》1996,21(3-4):381-398
Conclusion The ethnic Hungarians and the Romanians share a number of myths about their ancestors and about their homeland, Transylvania. I fully agree with Anthony D. Smith, who states that the core of ethnic identity is made up of a myth-symbol complex, consisting of myths, symbols, historical memory and key values. According to Smith, myths and symbols guarantee the preservation and the passing down to future generations of ethnic identity.25 The main problem with the ethnic Hungarians and the Romanians of Transylvania is that their convictions are not compatible, they are even contradictory. In the ethnic Hungarians' view, Transylvania is in fact Hungarian, but it was taken from them by Romania in 1920. According to the Romanians, Transylvania is Romanian but for centuries mistakenly considered as Hungarian by the Hungarians. The historical myths are part of the Hungarian as well as the Romanian collective consciousness. They strengthen cohesion within these groups but, as the convictions are incompatible, they widen the gap between them. In my view, these contradictory views are an additional cause of the current mutual oversensitivity, the mutual suspicion and mutual ignorance which characterize the relation between the two ethnic groups. I think that the success of the Romanian nationalist parties such as the PUNR and România Mare
26 among the Romanian villagers of Transylvania 27is partly due to their exploitation of these contradictory myths.However, the differing oral traditions in the villages do not cause open conflicts. That everyone in his own group passes on his own version helps to explain this. In mixed villages like Dumbrava and Mànàstireni, the sensitive issues are not discussed in ethnically mixed groups. Virtually everything to do with history is suppressed in the day-to-day life of the village. Nevertheless, that does not stop one ethnic group from gossiping about the other. Thus, mutual distrust persists. Such a sense of fear is a dangerous breeding-ground because it can easily be exploited by nationalist parties. When anything occurs in politics which appeals to these feelings of fear and distrust, two fronts are lined up in no time. This actually happened as a result of the controversy about the archaeological excavations in Cluj.Fortunately, there is a sufficiently large number of people who realize that this is pointless and who see through the extremist nationalist party leaders' malice. Bearing in mind the tragic example of the former Yugoslavia, they advocate understanding and peaceful interethnic co-existence.I have touched on only one of several conditions for ethnic survival and revival: the shared historical myths. Research in this field is essential if we are to begin to understand, and, thus, perhaps to alleviate, the many social and political problems in this area.Greet Van de Vyver is Aspirant of the National Foundation for Scientific Research of Belgium and a Ph.D. Candidate in the Department of Social and Cultural Anthropology, Catholic University of Leuven in Belgium. 相似文献
2.
Anthony D. Smith 《Ethnic and racial studies》2013,36(3):340-367
Although the nation, as a named community of history and culture, possessing a common territory, economy, mass education system and common legal rights, is a relatively modern phenomenon, its origins can be traced back to pre‐modern ethnic communities. Such named ethnies with their myths of common descent, common memories, culture and solidarity, and associations with a homeland, are found in both the ancient and the medieval periods in many areas of the world. Two kinds of ethnie are important for the origins and routes of the formation of nations. Territorial, ‘civic’ nations tend to develop from aristocratic ‘lateral’ ethnies through a process of ‘bureaucratic incorporation’ of outlying regions and lower classes into the ethnic culture of the upper classes, as occurred in France, England and Spain. The more numerous ‘ethnic’ nations, on the other hand, have emerged from demotic ‘vertical’ ethnies through processes of cultural mobilization that turn an often religiously defined and passive community into an active, politicized nation. Here the intellectuals and professionals replace the state as agents of popular mobilization, creating new ‘maps’ and ‘moralities’ through the uses of landscape and golden ages of a rediscovered and reconstructed communal past, as in Ireland, Finland and Switzerland. It is from these often ancient ties and sentiments that modern nations draw much of their power and durability today. 相似文献
3.
Virginia Tilley 《Ethnic and racial studies》2013,36(3):497-522
Theoretical debates on ethnicity suffer from a general confusion about the divergent meanings which academics ascribe to key terms. ‘Primordialist’ approaches include biological, psychological and cultural explanations, whose conflation tends to confuse proponents and critics alike. ‘Instrumentalist’ approaches conflate all ethnic movements within a profile of political opportunism, failing to recognize the varying degrees to which underlying social‐institutional incompatibilities may contribute to ethnic conflict. ‘Constructivist’ approaches vacillate between a focus on the influence of intellectual ethnic discourse and an understanding of ethnic identity as developing out of wider bodies of social experience. Greater attention to the varying contribution of ‘deep’ culture to ethnic conflict can clarify why these subschools find such differences among ethnic movements, which can indeed be understood to vary along a spectrum of political functions: at one pole, ethnic movements seek to inflate ethnic sentiment for political purposes; at the other, they seek rather to reconstruct the existing political position of a distinct cultural formation. This distinction can permit more appropriate policy‐making towards the resolution of ethnic conflict, yet raises new challenges to the biases of the researcher. 相似文献
4.
Pedro Abellán Jens‐Christian Svenning 《Biological journal of the Linnean Society. Linnean Society of London》2014,113(1):13-28
In Europe, southern peninsulas served as major refugia during Pleistocene cold periods. However, growing evidence has revealed complex patterns of glacial survival within these southern regions, with multiple glacial refugia within each larger refugial area. We investigated the extent to which patterns of endemism and phylogeographic are concordant across animal species in the Iberian Peninsula, one of the most important unglaciated areas in Europe during the Pleistocene, can be explained in terms of climatic stability. We found that historical climatic stability (notably climate velocity measures integrating macroclimatic shifts with local spatial topoclimate gradients) was often among the most important predictors of endemic species richness for different taxonomic groups using models that also incorporated measures of modern climate. Furthermore, for some taxonomic groups, climatic stability was also correlated with patterns of spatial concordance in interpopulation genetic divergence across multiple taxa, and private haplotypes were more frequently found in relatively stable areas. Overall, our results suggest that both endemism patterns and cross‐taxa concordant phylogeographic patterns across the Iberian Peninsula to some extent are linked to spatial variation in Late Quaternary climate stability, in agreement with the proposed ‘refugia‐within‐refugia’ scenario. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113 , 13–28. 相似文献
5.
A central goal in evolutionary ecology is to characterize and identify selection patterns on the optimal phenotype in different environments. Physiological traits, such as hormonal responses, provide important mechanisms by which individuals can adapt to fluctuating environmental conditions. It is therefore expected that selection shapes hormonal traits, but the strength and the direction of selection on plastic hormonal signals are still under investigation. Here, we determined whether, and in which way, selection is acting on the hormones corticosterone and prolactin by characterizing endocrine phenotypes and their relationship with fitness in free‐living great tits, Parus major. We quantified variation in circulating concentrations of baseline and stress‐induced corticosterone and in prolactin during the prebreeding (March) and the breeding season (May) for two consecutive years, and correlated these with reproductive success (yearly fledgling number) and overwinter survival in female and male individuals. In both years, individuals with high baseline corticosterone concentrations in March had the highest yearly fledgling numbers; while in May, individuals with low baseline corticosterone had the highest yearly reproductive success. Likewise, individuals that displayed strong seasonal plasticity in baseline corticosterone concentrations (high in March and low in May) had the highest reproductive success in each year. Prolactin concentrations were not related to reproductive success, but were positively correlated to the proximity to lay. Between‐year plasticity in stress‐induced corticosterone concentrations of males was related to yearly variation in food abundance, but not to overall reproductive success. These findings suggest that seasonally alternating directional selection is operating on baseline corticosterone concentrations in both sexes. The observed between‐year consistency in selection patterns indicates that a one‐time hormone sample in a given season can allow the prediction of individual fitness. 相似文献
6.
Food availability as a major driver in the evolution of life‐history strategies of sibling species
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Life‐history theory predicts trade‐offs between reproductive and survival traits such that different strategies or environmental constraints may yield comparable lifetime reproductive success among conspecifics. Food availability is one of the most important environmental factors shaping developmental processes. It notably affects key life‐history components such as reproduction and survival prospect. We investigated whether food resource availability could also operate as an ultimate driver of life‐history strategy variation between species. During 13 years, we marked and recaptured young and adult sibling mouse‐eared bats (Myotis myotis and Myotis blythii) at sympatric colonial sites. We tested whether distinct, species‐specific trophic niches and food availability patterns may drive interspecific differences in key life‐history components such as age at first reproduction and survival. We took advantage of a quasi‐experimental setting in which prey availability for the two species varies between years (pulse vs. nonpulse resource years), modeling mark‐recapture data for demographic comparisons. Prey availability dictated both adult survival and age at first reproduction. The bat species facing a more abundant and predictable food supply early in the season started its reproductive life earlier and showed a lower adult survival probability than the species subjected to more limited and less predictable food supply, while lifetime reproductive success was comparable in both species. The observed life‐history trade‐off indicates that temporal patterns in food availability can drive evolutionary divergence in life‐history strategies among sympatric sibling species. 相似文献
7.
Daniel R. Prez Florencia Gonzlez Cristian Ceballos María E. Oneto James Aronson 《Restoration Ecology》2019,27(5):1105-1116
In large areas of the world that are deeply scarred by desertification and hampered by low capacity for natural regeneration, the scaling up of ecological restoration and rehabilitation can be achieved only if it is low in cost with high return on investment, and shows promise of providing long‐lasting social‐economic as well as ecological benefits. In the Monte Austral region of Patagonia Argentina, concerted efforts are underway to facilitate scaling up of ecological restoration and rehabilitation practices. Here, we evaluate financial costs and preliminary results of direct seeding as compared to outplanting of nursery‐grown seedlings of three native species (Atriplex lampa, Senecio subulatus var. subulatus, and Hyalis argentea var. latisquama) considered to be high‐priority dryland framework species. Comparative success is expressed in terms of plant survival and in monetary terms. The three candidate species showed low survival rates, ranging from 4.3 to 22.3%, after the first summer following direct seeding. In contrast, survival rates for planted seedlings of the same three taxa varied between 84 and 91%, after the first summer following reintroduction. However, cost of direct seeding varied between 1,693 and 1,772 US$ less per hectare, that is, 64% less than the cost of outplanting nursery seedlings. Therefore, in the search for ways to scale up ecological restoration and rehabilitation in drylands, direct seeding should receive more attention. We discuss the social and ecological perspectives and the way forward for direct seeding techniques in Patagonia. We also consider how costs could be reduced and effectiveness improved in large‐scale efforts. 相似文献
8.
Rafael Bello‐Bedoy Isaac González‐Santoyo Martín Alejandro Serrano‐Meneses David Vrech Miguel Rivas Roberto Munguía‐Steyer Alex Córdoba‐Aguilar 《Biological journal of the Linnean Society. Linnean Society of London》2015,114(2):327-334
Recent studies have linked static allometry of sexual traits to selective advantages, in terms of sexual selection. An underlying, yet untested, assumption is that the allometry of sexual traits confers higher mating success and/or survival. Here, we investigated whether the allometry of two sexual traits is related to male mating success and survival in two species of damselflies: wing size in Paraphlebia zoe and the red‐pigmented wing spot in Hetaerina americana. We used large field‐based data sets of marked‐recaptured animals, in which we recorded male mating success and survival. Both sexual traits exhibited hyperallometric patterns; however, allometry was not linked to either mating success or survival. These results indicate that, at least during the period of sexual competition, allometry does not seem to be adaptive. Although our results may only apply to our damselfly study subjects (which nevertheless would require further tests in different seasons and/or study sites), our findings should encourage researchers to evaluate at least whether the assumed adaptiveness of sexual trait allometry holds for their study animals. © 2015 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, 114 , 327–334. 相似文献
9.
Winter is becoming warmer and shorter across the northern hemisphere, and reductions in snow depth can decrease tree seedling survival by exposing seedlings to harmful microclimates. Similarly, herbivory by small mammals can also limit the survival and distribution of woody plants, but it is unclear whether winter climate change will alter small‐mammal herbivory. Although small‐scale experiments show that snow removal can either increase or decrease both soil temperatures and herbivory, we currently lack snow‐removal experiments replicated across large spatial scales that are needed to understand the effect of reduced snow. To examine how winter herbivory and snow conditions influence seedling dynamics, we transplanted Acer saccharum and Tsuga canadensis seedlings across a 180 km latitudinal gradient in northern Wisconsin, where snow depth varied seven‐fold among sites. Seedlings were transplanted into one of two herbivory treatments (small‐mammal exclosure, small‐mammal access) and one of two late‐winter snow removal treatments (snow removed, snow unmanipulated). Snow removal increased soil freeze‐thaw frequency and cumulative growing degree‐days (GDD), but the magnitude of these effects depended on forest canopy composition. Acer saccharum survival decreased where snow was removed, but only at sites without conifers. Excluding small mammals increased A. saccharum survival at sites where the small‐mammal herbivore Myodes gapperi was present. Excluding small mammals also increased T. canadensis survival in plots with < 5 cm snow. Because variation in canopy composition and M. gapperi presence were important predictors of seedling survival across the snow‐depth gradient, these results reveal complexity in the ability to accurately predict patterns of winter seedling survival over large spatial scales. Global change scenarios that project future patterns of seedling recruitment may benefit from explicitly considering interactions between snow conditions and small‐mammal winter herbivory. 相似文献
10.
The “value of information” (VOI) is a generic term for the increase in value resulting from better information to guide management, or alternatively, the value foregone under uncertainty about the impacts of management (Yokota and Thompson, Medical Decision Making 2004; 24 : 287). The value of information can be characterized in terms of several metrics, including the expected value of perfect information and the expected value of partial information. We extend the technical framework for the value of information by further developing the relationship between value metrics for partial and perfect information and describing patterns of their performance. We use two different expressions for the expected value of partial information to highlight its relationship to the expected value of perfect information. We also develop the expected value of partial information for hierarchical uncertainties. We highlight patterns in the value of information for the Svalbard population of the pink‐footed goose (Anser brachyrhynchus), a population that is subject to uncertainty in both reproduction and survival functions. The framework for valuing information is seen as having widespread potential in resource decision making, and serves as a motivation for resource monitoring, assessment, and collaboration. 相似文献
11.
《Biodemography and social biology》2013,59(1-2):71-81
Abstract Hierarchical regression analyses and response surfaces were used in an investigation of relationships between sibling variables and adolescents’ perceptions of their family environments, after the impact on the perceptions of earlier family measures was taken into account. The analyses involved Australian adolescents and included 260 Anglo‐Australian, 120 Greek, and 90 Southern Italian families. Regression models included terms to test for possible linear, interaction, and curvilinear associations between the sibling and family environment variables. The analysis suggested the propositions that: (a) parents from different ethnic groups create different learning environments for their children and that there are ethnic‐group variations in how children perceive their family environments, (b) there are ethnic‐group variations in relationships between sibling variables and adolescents’ perceptions of their parents’ support for learning, and (c) within ethnic groups the relationships between sibling variables and perceived parental support for learning differ, depending on whether the support of fathers or mothers is being considered. 相似文献
12.
Josh R. Auld Ryan Houser 《Evolution; international journal of organic evolution》2015,69(10):2793-2798
Reproductive performance is often age‐dependent, showing patterns of improvement and/or senescence as well as trade‐offs with other traits throughout the lifespan. High levels of extrinsic mortality (e.g., from predators) have been shown to sometimes, but not always, select for accelerated actuarial senescence in nature and in the lab. Here, we explore the inductive (i.e., plastic) effects of predation risk (i.e., nonlethal exposure to chemical cues from predators) on the reproductive success of freshwater snails (Physa acuta). Snails were reared either in the presence or absence of chemical cues from predatory crayfish and mated early in life or late in life (a 2 × 2 factorial design); we measured egg hatching and early post‐hatching survival of their offspring. Both age and predation risk reduced reproductive success, illustrating that predation risk can have a cross‐generational effect on the early survival of juveniles. Further, the decline in reproductive success was over three times faster under predation risk compared to the no‐predator treatment, an effect that stemmed from a disproportionate, negative effect of predation risk on the post‐hatching survival instead of hatching rate. We discuss our results in terms of a hypothesized consequence of elevated stress hormone levels. 相似文献
13.
Nicolas Degallier Jacques Servain Paulo Sérgio Lucio Alexis Hannart Bruno Durand Raimundo Nonato de Souza Zolyde Mota Ribeiro 《Journal of vector ecology》2012,37(2):428-441
It is generally assumed that the daily probability of survival of mosquitoes is independent of age. To test this assumption we have conducted a three‐year experimental fieldwork study (2005–2007) at Fortaleza‐CE in Brazil, determining daily survival rates of the dengue vector Aedes aegypti (L.). Survival rates of adult Ae. aegypti may be age‐dependent and the statistical analysis is a sensitive approach for comparing patterns of mosquito survival. The mosquito survival data were better fit by a Weibull survival function than by the more traditionally used Gompertz or logistic survival functions. Gompertz, Weibull, or logistic survival functions often fit the survival, and the tails of the survival curves usually appear to fall between the values predicted by the three functions. We corroborate that the mortality of Ae. aegypti in semi‐natural conditions may no more be considered as a constant phenomenon during the life of adult mosquitoes but varies according to the age and environmental conditions under a tropical climate. This study estimates the variability in the survival rate of Ae. aegypti and environmental factors that are related to such variability. The statistical analysis shows that the fitting ability, concerning the hazard function, was in decreasing order: Seasonal Cox, the three‐parameter Gompertz, and the three‐parameter Weibull, that was similar to the three‐parameter logistic. The advantage of using the Cox model is that it is convenient for exploring the relationship between survival and several explanatory variables. The Cox model has the advantage of preserving the variable in its original quantitative form and of using a maximum of information. The survival analyses indicate that mosquito mortality is both age‐ and environment‐dependent. 相似文献
14.
Although body size can affect individual fitness, ontogenetic and spatial variation in the ecology of an organism may determine the relative advantages of size and growth. During an 8‐year field study in the Bahamas, we examined selective mortality on size and growth throughout the entire reef‐associated life phase of a common coral‐reef fish, Stegastes partitus (the bicolour damselfish). On average, faster‐growing juveniles experienced greater mortality, though as adults, larger individuals had higher survival. Comparing patterns of selection observed at four separate populations revealed that greater population density was associated with stronger selection for larger adult size. Large adults may be favoured because they are superior competitors and less susceptible to gape‐limited predators. Laboratory experiments suggested that selective mortality of fast‐growing juveniles was likely because of risk‐prone foraging behaviour. These patterns suggest that variation in ecological interactions may lead to complex patterns of lifetime selection on body size. 相似文献
15.
Spatially variable coevolution between a haemosporidian parasite and the MHC of a widely distributed passerine
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The environment shapes host–parasite interactions, but how environmental variation affects the diversity and composition of parasite‐defense genes of hosts is unresolved. In vertebrates, the highly variable major histocompatibility complex (MHC) gene family plays an essential role in the adaptive immune system by recognizing pathogen infection and initiating the cellular immune response. Investigating MHC‐parasite associations across heterogeneous landscapes may elucidate the role of spatially fluctuating selection in the maintenance of high levels of genetic variation at the MHC. We studied patterns of association between an avian haemosporidian blood parasite and the MHC of rufous‐collared sparrows (Zonotrichia capensis) that inhabit environments with widely varying haemosporidian infection prevalence in the Peruvian Andes. MHC diversity peaked in populations with high infection prevalence, although intra‐individual MHC diversity was not associated with infection status. MHC nucleotide and protein sequences associated with infection absence tended to be rare, consistent with negative frequency‐dependent selection. We found an MHC variant associated with a ~26% decrease in infection probability at middle elevations (1501–3100 m) where prevalence was highest. Several other variants were associated with a significant increase in infection probability in low haemosporidian prevalence environments, which can be interpreted as susceptibility or quantitative resistance. Our study highlights important challenges in understanding MHC evolution in natural systems, but may point to a role of negative frequency‐dependent selection and fluctuating spatial selection in the evolution of Z. capensis MHC. 相似文献
16.
Objective: This study investigated ethnic and sex differences in the distribution of fat during childhood and adolescence. Design and Methods : A cross‐sectional sample (n = 382), aged 5–18 years, included African American males (n = 84), White males (n = 96), African American females (n = 118), and White females (n = 84). Measures for total body fat (TBF) mass and abdominal adipose tissue (total volume and L4‐L5 cross‐sectional area) for both subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) depots were assessed by dual‐energy X‐ray absorptiometry and magnetic resonance image, respectively. Analyses of covariance (ANCOVAs) were used to determine ethnic and sex differences in TBF (adjusted for age) and ethnic and sex differences in SAT and VAT (adjusted for both age and TBF). Results: Age‐adjusted TBF was greater in African Americans (P = 0.017) and females (P < 0.0001) compared with Whites and males, respectively. In age‐ and TBF‐adjusted ANCOVAs, no differences were found in the SAT. The VAT volume was, however, greater in Whites (P < 0.0001) and males (P < 0.0001) compared with African Americans and females, respectively. Similar patterns were observed in SAT and VAT area at L4‐L5. Conclusions: The demonstrated ethnic and sex differences are important confounders in the prevalence of obesity and in the assignment of disease risk in children and adolescents. 相似文献
17.
Trophic and non-trophic pathways mediate apparent competition through post-dispersal seed predation in a Patagonian mixed forest 总被引:2,自引:0,他引:2
Post‐dispersal predation can be a major source of seed loss in temperate forests. Little is known, however, about how predator‐mediated indirect interactions such as apparent competition alter survival patterns of canopy tree seeds. Understorey plants may enhance tree seed predation by providing sheltered habitat to granivores (non‐trophic pathway). In addition, occurrence of different tree seeds in mixed patches may lead to short‐term apparent competition between seed types, because of the granivores’ foraging response to changes in food patch quality (trophic pathway). We hypothesised that understorey bamboo cover and mixing of seed species in food patches would both increase tree seed predation in a Nothofagus dombeyi?Austrocedrus chilensis forest in northern Patagonia, Argentina. Seed removal experiments were conducted for three consecutive years (2000–2002) differing in overall granivory rates. Seed patch encounter and seed removal rates were consistently higher for the larger and more nutritious Austrocedrus seeds than for the smaller Nothofagus seeds. Seed removal was greater beneath bamboo than in open areas. This apparent competition pathway was stronger in a low‐predation year (2000) than in high‐predation years (2001–2002), suggesting a shift in microhabitat use by rodents. Patch composition had a significant, though weaker, impact on seed survival across study years, whereas seed density per patch enhanced encounter rates but did not influence seed removal. Removal of the less‐preferred Nothofagus seeds increased in the presence of Austrocedrus seeds, but the reciprocal indirect effect was not observed. However, this non‐reciprocal apparent competition between seed species was only significant in the high‐predation years. Our study shows that granivore‐mediated indirect effects can arise through different interaction pathways, affecting seed survival patterns according to the predator's preference for alternative seed types. Moreover, results indicate that the occurrence and relative strength of trophic vs non‐trophic pathways of apparent competition may change under contrasting predation scenarios. 相似文献
18.
Andrés García‐Reina María Juliana Rodríguez‐García Guillermo Ramis José Galián 《Insect Science》2017,24(3):358-370
The rust red flour beetle, Tribolium castaneum (Herbst, 1797) (Coleoptera: Tenebrionidae), is a pest of stored grain and one of the most studied insect model species. Some of the previous studies involved heat response studies in terms of survival and heat shock protein expression, which are regulated to protect other proteins against environmental stress conditions. In the present study, we characterize the impedance profile with the xCELLigence Real‐Time Cell Analyzer and study the effect of increased temperature in cell growth and viability in the cell line BCIRL‐TcA‐CLG1 (TcA) of T. castaneum. This novel system measures cells behavior in real time and is applied for the first time to insect cells. Additionally, cells are exposed to heat shock, increased salinity, acidic pH and UV‐A light with the aim of measuring the expression levels of Hsp27, Hsp68a, and Hsp83 genes. Results show a high thermotolerance of TcA in terms of cell growth and viability. This result is likely related to gene expression results in which a significant up‐regulation of all studied Hsp genes is observed after 1 h of exposure to 40 °C and UV light. All 3 genes show similar expression patterns, but Hsp27 seems to be the most affected. The results of this study validate the RTCA method and reveal the utility of insect cell lines, real‐time analysis and gene expression studies to better understand the physiological response of insect cells, with potential applications in different fields of biology such as conservation biology and pest management. 相似文献
19.
Survival in northern microrefugia in an endemic Carpathian gammarid (Crustacea: Amphipoda)
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Denis Copilaş‐Ciocianu Alina‐Andreea Zimţa Michał Grabowski Adam Petrusek 《Zoologica scripta》2018,47(3):357-372
Gammarus leopoliensis (Crustacea: Amphipoda) is considered a north‐eastern Carpathian endemic species and therefore can be regarded as an appropriate model for testing the hypothesis of Quaternary glacial survival in northern microrefugia. However, 250 km south, the south‐western Carpathians harbour populations that resemble phenotypically both G. leopoliensis and Gammarus kischineffensis, a similar species distributed east of the Carpathians. We used maximum‐likelihood and Bayesian methods to evaluate the phylogenetic relationships of these three taxa based on mitochondrial and nuclear markers, and quantitatively compared diversity patterns, phylogeography and divergence times among north‐eastern and south‐western Carpathian taxa. Results indicate that G. leopoliensis and the south‐western populations form together a strongly supported group (G. leopoliensis s.l.) which, along with G. kischineffensis, belongs to the Gammarus balcanicus clade. This group contains 12 lineages mainly of Pliocene age. G. leopoliensis consists of two widely distributed and recently expanded allopatric sister lineages that diverged from the southern ones ca. 4 Ma, indicating long‐term survival in northern microrefugia. The southern lineages are micro‐endemic and display a scattered distribution, suggesting a more ancient, relict pattern. We conclude that the contrasting diversity patterns between the disjunct distributional areas of G. leopoliensis s.l. reflect differential survival of lineages across the latitudinal gradient, offering a promising system for comparing the evolutionary ecology of lineages persisting in latitudinally disconnected microrefugia. These results fill an important gap in the knowledge of European gammarid biogeography and reveal that all Carpathian Gammarus taxa are ancient and diverse species complexes. 相似文献
20.
Jan Wunder Bjrn Reineking Jean‐Franois Matter Christof Bigler Harald Bugmann 《植被学杂志》2007,18(4):525-534
Question: How well can mortality probabilities of deciduous trees(Fagus sylvatica) and conifers (Abies alba) be predicted using permanent plot data that describe growth patterns, tree species, tree size and site conditions? Location: Fagus forests in the montane belt of the Jura folds (Switzerland). Method: Permanent plot data were used to develop and validate logistic regression models predicting survival probabilities of individual trees. Backward model selection led to a reduced model containing the growth‐related variable ‘relative basal area increment’ (growth‐dependent mortality) and variables not directly reflecting growth such as species, size and site (growth‐independent mortality). Results: The growth‐mortality relationship was the same for both species (growth‐dependent mortality). However, species, site and tree size also influenced mortality probabilities (growth‐independent mortality). The predicted survival probabilities of the final model were well calibrated, and the model showed an excellent discriminatory power (area under the receiver operating characteristic curve = 0.896). Conclusion: Mortality probabilities of Fagus sylvatica and Abies alba can be predicted with high discriminatory power using a well calibrated logistic regression model. Extending this case study to a larger number of tree species and sites could provide species‐ and site‐specific tree mortality models that allow for more realistic projections of forest succession. 相似文献