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1.
The decision of the International Court of Justice in the Australia/Japan Whaling Case marks an advance in the law of the sea and the obligation on states to cooperate in common ocean resource regimes. The Court found substantially for Australia, prohibiting Japan's long-running program to capture large cetaceans in the Southern Ocean around Antarctica for scientific research. The Court's discussion of the criteria for states to design and implement scientific research whaling programs is assessed, as is the obligation for cooperation in such research and ocean research generally. The result for whaling and for the future work of the International Whaling Commission is considered.  相似文献   

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Although many species of marine mega-vertebrates are threatened as a result of human activity, some populations are showing promising signs of recovery following decades of protection. In this study, we report on the status of the South Atlantic’s largest green turtle (Chelonia mydas) nesting aggregation at Ascension Island, 70 years after legal protection and the cessation of commercial turtle harvesting that decimated the population. Using a monitoring dataset spanning 36 years, we modelled long-term trends in nesting activity at both a rookery level and across individual nesting beaches and beach clusters. Since monitoring began in 1977, the average number of green turtle clutches deposited annually at Ascension Island has increased sixfold, from approximately 3,700 to 23,700; a trend that has been accompanied by a significant decrease in the average size of nesting females. Interestingly, however, rates of increase in nesting activity have varied dramatically among nesting beaches, ranging from 0.4 to 6 % growth per annum. More than 97 % of this variation could be explained by distance from the main human settlement of Georgetown—the historic centre of turtle harvesting—with beaches closer to Georgetown experiencing the most rapid growth. More rapid population growth close to human centres seems counterintuitive, but may reflect the more intensive depletion of these accessible, local stocks during the harvesting era. Overall, the Ascension Island green turtle population appears to be recovering strongly, mirroring positive trends for this species across many parts of its geographic range. While not a cause for complacency, these trends are encouraging and demonstrate the capacity of marine megafauna to rebound when anthropogenic pressures are alleviated through conservation action.  相似文献   

4.

This article examines how racial and gendered images of South Asia were played out in performance at the American circus around 1900. These representations reinforced the Anglo‐American construct of a racial hierarchy in which South Asians were depicted to be static, and unable to keep pace with the Anglo‐American “race”. American circus spectacles featuring Indian subjects glorified British imperialism and helped to popularize the common colonialist stereotype that a minority of English officials were needed to rule millions of Indians. The American circus, as the most popular form of American public entertainment in an era before movies and television, helped to form a constellation of racial and sexual stereotypes concerning South Asia which continue to this day.  相似文献   

5.
In the immediate aftermath of global extinctions, organisms were normally much smaller than those prior to these events. This ‘Lilliput Effect’ can be subdivided into two types: 1) a specific type, following the original definition of the effect which targets species-level taxa associated with inhospitable environments, and 2) a more general type, related to the reactions of higher-rank taxa above the species-level. The body sizes of brachiopods from South China through the Ordovician and Silurian transition (Late Katian, Hirnantian, and earliest Rhuddanian) are compared at generic, superfamilial, ordinal, and class levels. The results indicate that the body sizes of the taxa of lower rank (e.g. genus-level) are highly variable within these different intervals. The type of evidence for the Lilliput Effect through the end Ordovician mass extinction is thus quite different from that of the end Permian mass extinction probably reflecting differences in the intensity of these two major bioevents. However, the relationships between the contrasting trends in body-size change of some taxa of higher rank (e.g. at the ordinal-level) and the relative dominance of these taxa in the latest Ordovician and earliest Silurian suggest that the brachiopods of the two major Ordovician groups, the strophomenoids and orthoids, adopted different survival strategies during and immediately after the crisis from those of the pentamerides and rhynchonellides, that were common in Silurian assemblages.  相似文献   

6.
Translocations or other movements of wildlife sometimes accomplish their intended objectives, but unforeseen consequences may arise and disrupt locally adapted ecological communities, restructure or dilute genetic integrity of populations or subspecies of the moved organism, and otherwise negatively influences a species’ long‐term fitness. Two historical populations of Mottled Ducks (Anas fulvigula) exist and are endemic to (1) Mexico and the West‐Gulf Coast (A. f. maculosa) regions of the United States and (2) Florida (A. f. fulvigula). From 1975 to 1983, 1285 Mottled Ducks from Florida, Louisiana, and Texas were released to coastal South Carolina, primarily to ultimately establish a legally harvestable population. This movement stirred mixed reactions amid the conservation community. Contemporary information suggests an increasing Mottled Duck population in South Carolina and possibly dispersing into Georgia. Herein, I objectively discuss the potential consequences of this new population per the birds’ evolution, ecology, and management. Ultimately, I suggest that this translocation is a long‐term benefit to the species.  相似文献   

7.
The US government has simultaneously increased efforts to close its border to unauthorized migrants, and opened the border to increasing flows of tourists from Mexico. In this paper I focus on the experiences of Mexican tourists who are able to freely cross the USA–Mexico border with US visas, given that their unique status as tourists from Mexico is an important element to consider because it organizes their daily lives, their moral understandings, and their experiences across the USA–Mexico border. I show how Global South cosmopolitans from Mexico benefit from class privilege in Mexico, but become legally vulnerable in the USA due to their racialization as Mexicans and lack of citizenship rights. This paper draws on ethnographic data and in-depth interviews collected in the border town of Mexicali, Baja California, Mexico between July 2009 and August 2010.  相似文献   

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Guanay cormorants Phalacrocorax bougainvilli aredistributed mostly on the Pacific coast of Peru and northern Chile. A smallpopulation of around 50 pairs was described on the Patagonian Atlantic coast inthe late 1960s. Further records have revealed a progressive decrease of thispopulation. During 1999 we looked for guanay cormorants at those Atlanticcolonies where the species was recorded in the past. Only four individuals weredetected in one colony (Punta Lobería), and all of them were mated withking cormorants P. albiventer. In addition, we recordedhybrids between guanay and king cormorants mated with pure king and imperialcormorants P. atriceps. Causes of the population declineare unknown. Since guanay cormorants inhabiting the Atlantic coast could be agenetically differentiated population, we emphasize the need for molecularstudies. If genetic polymorphism is detected, the capture of remnant individualsin order to constitute a genetic stock should be considered.  相似文献   

9.
The complete late Campanian–Maastrichtian succession of the South Atlantic reference DSDP Site 525A has been investigated to establish a detailed record of calcareous nannofossil biohorizons. A complete holostratigraphy of the core is presented for this interval and allows for global correlations to other Tethyan and Boreal reference sections for that interval. The new study allows for proposing a new time scale with a tie of Tethyan and Boreal nannofossil zonations. A new subzonation is proposed for the late Campanian UC16 Zone in the Tethyan Realm and the last occurrences of Uniplanarius trifidus and Zeugrhabdotus praesigmoides are demonstrated as markers of the Campanian–Maastrichtian boundary. The difference between cumulative first and last occurrences reflects the turnover dynamics of calcareous nanoplankton in the South Atlantic and highlights 6 major events. Five of them appear well related to major changes in sea-surface temperatures whereas the sixth event is likely the expression of a global decrease in primary productivity in the late Maastrichtian. Surprisingly, the turnover dynamics in calcareous nannoplankton appears completely unrelated to that observed in planktic foraminifera which shows only 4 major events with different timings. The two groups thus seem to have responded either very differently to similar environmental constraints or to different direct environmental constraints in the photic zone, although caused by the same global changes in climate.  相似文献   

10.
The deposition of eggs by this strain of Callosobruchus maculatus (Fab.) (Bruchidae: Coleoptera) departs from randomness in three ways; eggs are uniformly dispersed, oviposition rates drop when beans begin to carry 2 or more eggs, and there are sharp host preferences. Using random egg placement for the unspecialized condition, these traits are evaluated for their effect on a female's contributions of offspring to the next generation (R0, the net reproductive rate). The major increases in R0 result from females dispersing eggs so uniformly that larval competition is either reduced or eliminated. Females reduce their oviposition rate when the larva from an egg added to a bean is almost certain to die in competitive encounters. Host preferences and larval survival in a host are positively associated with the abundance of the host in South India. The three oviposition traits act together to give and R0 that is 25–50% than that of eggs placed at random. These traits are known to be variable and heritable, hence, the conditions necessary for natural selection are statisfied.
Résumé Le taux partiel de reproduction nette (R inf0 sup* ) dépend de l'espèce de la plante sur laquelle les ufs sont pondus et du nombre de larves entrant dans la graine. La survie larvaire est réduite par 1/(le nombre de larves par graine) parce qu'une seule larve se développe dans une graine. La fécondité n'est pas modifiée par la compétition subie par les larves, la mortalité larvaire a l'effet le plus important sur R inf0 sup* . Les femelles éliminent ou réduisent la compétition larvaire en dispersant leurs ufs uniformément et font si peu d'erreurs avec une hyperdispersion que l'évolution d'un comportement plus précis n'accroîtrait R inf0 sup* que de 4% au maximum. Des femelles retournant à une distribution des ufs au hasard provoqueraient une réduction de R inf0 sup* de 25% au moins.Les légumineuses généralement cultivées dans l'Inde du Sud sont des hôtes acceptables quand elles sont présentées seules. Le choix des femelles entre 2 hôtes élève R inf0 sup* de 30% ou plus par rapport à une distribution au hasard. Les préférences les plus nettes concernent des combinaisons présentant la plus grande différence de R inf0 sup* . Les femelles qui hyperdispersent leurs ufs, choisissent leurs hôtes et évitent les pertes par compétition en empêchant que les ufs ne donnent plus de descendants que ne le ferait une ponte au hasard.Les particularités de la ponte sont variables et héritables. Les lignées se sélectionnent bien, en fonction de la dispersion de leurs ufs sur les graines, de la discrimination des plantes hôtes, et de la modulation de leur taux de ponte. La sélection naturelle maintient ces particularités du comportement d'une façon sédentaire.
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11.
The classic Chengjiang Lagerstätte (Lower Cambrian, Atdabanian stage: Yu''anshan Formation) Yunnan, southwestern China, has yielded, besides the exceptional and often controversial soft-bodied fossils, a fauna of primitive/early lingulid brachiopods. Diandongia pista (Rong 1974) is one of the commonest and most strongly mineralized of the phosphatic brachiopods from the Lagerstätte. The shells of this species have been found to commonly serve as a basibiont host. Epibionts comprise the coeval brachiopod Longtancunella chengjiangensis and the cone-shaped cnidarian-related Archotuba conoidalis, as well as rounded smaller-sized epizoans (lesser than 2 mm). A principle morphological analysis demonstrates that the ovoid and rounded organisms that often occur along the commissure of D. pista resemble small juvenile or immature brachiopods. Epibiont-bearing shells of D. pista with soft-tissue preservation demonstrate that the host brachiopods were overgrown while alive, and provide an argument for D. pista having a semi-infaunal life style with only the slim pedicle embedded in sediment. The epibiotic association sheds direct light on the ecology of Cambrian brachiopods in soft-substrate marine environments. The Chengjiang fossils demonstrate that the Early Cambrian brachiopods, as compared with recent lingulids, occupied different and a wider spectrum of ecological niches and tiers of space.  相似文献   

12.
An analysis of pellets regurgitated indicated adult kelp gulls (Larus dominicanus) on the South Shetland Islands consumed predominantly intertidal prey, whereas previous studies at Antarctic Peninsula sites have reported kelp gulls consuming predominantly pelagic species. The pellets collected at Nelson Island during the chick-rearing period indicated that the limpet Nacella concinna was their most frequent prey, followed by carrion, gammariids, snails and krill. Fish were scarcely represented. Also, regurgitated stomach contents of chicks showed that limpets and carrion were the most frequent food items, accounting for 70% of the mass. However, gammariids were particularly important by number. Significant differences were observed in the overall comparison of the diet as reflected by the two sampling methods. In general, the importance of pelagic prey was negligible when compared to intertidal or scavenged prey. Our results differ greatly from those reported for the Antarctic Peninsula, where chicks were almost exclusively fed with the pelagic fish Pleuragramma antarcticum. These differences could be related to the abundance of pelagic resources in southernmost latitudes, and/or to the presence of more extensive intertidal foraging areas at the South Shetland Islands. Received: 7 October 1996 / Accepted: 14 July 1997  相似文献   

13.
The Hantam-Tanqua-Roggeveld subregion is part of the Succulent Karoo hotspot of biodiversity which stretches along the southwestern side of South Africa and Namibia. Forty Whittaker plots were surveyed in the spring of 2005, in eight vegetation associations, to gather diversity data for the Hantam, Tanqua Karoo and Roggeveld areas. Seven plot sizes were used to construct species–area curves using three different models namely: the untransformed linear function, the power function and the exponential function. In general, the power and exponential functions produced a more significant fit to the data than the untransformed linear function. Linear regressions using environmental parameters indicated that altitude, mean annual precipitation and mean annual temperature were significant predictors of species richness at the 1, 10, 100 and 1000 m2 scales. To illustrate the variation in species–area curves and species richness across the landscape, a transect through the study area is discussed. The transect stretches eastwards from the Tanqua Karoo across the escarpment into the Roggeveld and crosses five different vegetation associations. Differences between associations were found in species richness in the 1000 m2 plots. Each association also produced species–area curves with their own characteristics. Slope values for the samples within an association did not differ significantly, although the intercept value often did. Comparisons between associations along the transect revealed significant differences in the slope value between the associations, except for the Dicerothamnus rhinocerotis Mountain Renosterveld which did not differ significantly from the associations bordering it on either side.  相似文献   

14.
This brief essay reflects on the meaning and significance of ‘non-racialism’ in South Africa's recent past and present. I consider the version of non-racialism that shaped the transition from apartheid to a constitutional democracy as having had dual dimensions, ethical and strategic. Ethically, non-racialism has signified a principle of human recognition that exceeds the mere tolerance of difference. Strategically, non-racialism has afforded ways of managing and disciplining the historical realities of racial differences. The politicization of race in recent years has rendered the project of non-racialism more precarious: both its ethical and strategic dimensions merit further scrutiny, if the project is to be revitalized.  相似文献   

15.
We tested the validity of Bergmann’s rule and Rosenzweig’s hypothesis through an analysis of the geographical variation of the skull size of Otaria flavescens along the entire distribution range of the species (except Brazil). We quantified the sizes of 606 adult South American sea lion skulls measured in seven localities of Peru, Chile, Uruguay, Argentina, and the Falkland/Malvinas Islands. Geographical and environmental variables included latitude, longitude, and monthly minimum, maximum, and mean air and ocean temperatures. We also included information on fish landings as a proxy for productivity. Males showed a positive relationship between condylobasal length (CBL) and latitude, and between CBL and the six temperature variables. By contrast, females showed a negative relationship between CBL and the same variables. Finally, female skull size showed a significant and positive correlation with fish landings, while males did not show any relationship with this variable. The body size of males conformed to Bergmann’s rule, with larger individuals found in southern localities of South America. Females followed the converse of Bergmann’s rule at the intraspecific level, but showed a positive relationship with the proxy for productivity, thus supporting Rosenzweig’s hypothesis. Differences in the factors that drive body size in females and males may be explained by their different life-history strategies. Our analyses demonstrate that latitude and temperature are not the only factors that explain spatial variation in body size: others such as food availability are also important for explaining the ecogeographical patterns found in O. flavescens.  相似文献   

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The South African coastline can be divided into at least four temperature-defined marine bioregions, including the tropical north-east coast, the subtropical east coast, the warm-temperate south coast, and the cool-temperate west coast. There are also two biogeographical transition zones, the south-west coast and the south-east coast (or Wild Coast). The former is sometimes considered a distinct marine bioregion, but no such status has yet been suggested for the Wild Coast. Previous data on the distribution of a recently described but very common coastal crab, Hymenosoma longicrure, indicated that this species could be a Wild Coast endemic. If confirmed, this would be a first indication that this region harbours unique fauna, and that additional research is required to determine whether the Wild Coast constitutes a distinct bioregion that needs to be managed separately from other coastal regions. In the present study, we generated novel genetic data for H. longicrure and compared the species’ range with that of its southern African congeners. We found that H. longicrure occurs north of the Wild Coast, where its range overlaps with that of H. projectum. This finding rejects the idea that the Wild Coast harbours endemic fauna and suggests that the ranges of the two species may be linked to the subtropical and tropical bioregions, respectively, with some southward dispersal facilitated by the southward-flowing Agulhas Current. We conclude that there is as yet no compelling evidence that the Wild Coast is a distinct marine bioregion, and concur with previous biogeographical studies which have suggested that the Wild Coast is an area in which species from the subtropical and warm-temperate bioregions have overlapping ranges. Nonetheless, that fact that no biological information is available for the majority of the region’s estuaries highlights the necessity of comprehensively documenting the biodiversity of this understudied region to fully resolve this issue.  相似文献   

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《Palaeoworld》2023,32(3):411-428
In southwestern Mongolia, conodonts from the Indert Formation at its type locality in Shine Jinst were investigated to improve regional and global correlation of the uppermost Devonian–lowermost Carboniferous. The abundance and diversity of the conodont fauna is quite low in general, whereas representatives of Siphonodella, Protognathodus, Pseudopolygnathus, Polygnathus and Bispathodus have been collected from the Indert-Uul section. Five conodont biointervals, from the Bi. costatus-Pr. kockeli Interregnum (ckI) to the Siphonodella sandbergi Zone, could be recognized from the top Heermorit Member and the lower part of the Shombon Member, while the middle and upper parts of the Shombon Member cannot be zoned based on the conodonts. Absence of index fossils Si. sulcata, Pr. kuehni and Pr. kockeli hampered precise recognition of the Devonian–Carboniferous boundary (DCB) at Indert-Uul, but this transition is well delineated by typical uppermost Famennian and Tournaisian conodont assemblages. The DCB is tentatively placed at the base of the Shombon Member, consistent with the lithological boundary and the resuming of carbonate production during the DCB transitional interval.  相似文献   

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《Palaeoworld》2020,29(1):126-136
Permian–Triassic boundary microbialites (PTBMs) are organosedimentary carbonates formed immediately after the end-Permian mass extinction. All those reported PTBMs constrained by convincing conodont biozones are present stratigraphycally not higher than the Hindeodus parvus zone and most of them are dominated by thrombolites. This paper provides the first record of a brief, but spectacular development of stromatolite-dominated PTBMs within the basal Isarcicella isarcica conodont zone of the earliest Triassic from the Xikou section of South Qinling Block that was at the margin of the North China Block during the Permian–Triassic transition and was geographically separated from the major occurrence of post-extinction microbialites in the South China Block. This stromatolite cap overlies a 3.7-m-thick oolitic limestone and is composed of a lower 0.2-m-thick bed and an upper 0.5-m-thick bed, separated by a 0.2-m-thick greyish green siliciclastic mudstone. These two stromatolite beds mainly consist of columnar stromatolites with subordinate domal stromatolites. The intercolumn and interstitial spaces within the stromatolites are filled with oolitic grainstones. At the microscopic scale, laminoid structures in stromatolites comprise wavy, millimetric-domical and tangled laminae. The increased grain and fossil contents and/or bioturbation in the domical and tangled laminae indicate that the formation of these laminae is likely related to an increase in the populations and the disruptions by benthic metazoans, as well as an influx of sediment grains. The δ13Ccarb values fluctuate between 2‰ and 3‰ in the uppermost Permian strata; a distinct negative shift of 1.9‰ occurs at the topmost oolitic grainstone, just below the lower stromatolite bed, and the lowest value of −0.1‰ is located at the base of the upper stromatolite bed. The stratigraphic succession from stromatolites to thrombolites of the PTBMs may represent a transgressive succession and/or a transient ecosystem recovery immediately after the end-Permian mass extinction. The thrombolites-dominated PTBMs mainly developed in near-equator shallow marine geographic locations, and stromatolite-dominated PTBMs mainly developed at higher latitude settings, which probably indicates that a relatively lower diversity and abundance of marine benthic metazoans existed at higher latitudes after the end-Permian mass extinction.  相似文献   

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