首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
The global European eel (Anguilla anguilla) stock is critically endangered according to the IUCN, and the European Commission has urged the development of conservation plans aimed to ensure its viability. However, the complex life cycle of this panmictic species, which reproduces in the open ocean but spends most of its prereproductive life in continental waters (thus embracing a huge geographic range and a variety of habitat types), makes it difficult to assess the long‐term effectiveness of conservation measures. The interplay between local and global stressors raises intriguing cross‐scale conservation challenges that require a comprehensive modelling approach to be addressed. We developed a full life cycle model of the global European eel stock, encompassing both the oceanic and the continental phases of eel's life, and explicitly allowing for spatial heterogeneity in vital rates, availability of suitable habitat and settlement potential via a metapopulation approach. We calibrated the model against a long‐term time series of global European eel catches and used it to hindcast the dynamics of the stock in the past and project it over the 21st century under different management scenarios. Although our analysis relies on a number of inevitable simplifying assumptions and on data that may not embrace the whole range of variation in population dynamics at the small spatiotemporal scale, our hindcast is consistent with the general pattern of decline of the stock over recent decades. The results of our projections suggest that (i) habitat loss played a major role in the European eel decline; (ii) the viability of the global stock is at risk if appropriate protection measures are not implemented; (iii) the recovery of spawner escapement requires that fishing mortality is significantly reduced; and (iv) the recovery of recruitment might not be feasible if reproductive output is not enhanced.  相似文献   

2.
De Silva et al . (2007) present an overview of the distribution and conservation status of the endemic freshwater fish of Asia. Within that review they use data from the IUCN Red List of Threatened Species™ (2006) to conduct an analysis of the conservation status of those endemic fish species. Their analysis is incorrect and provides a very misleading impression of the level of threat to Asian freshwater fish and to freshwater fish at the global scale. The errors stem from a misinterpretation of the data presented on the IUCN Red List. The sources of errors are discussed below and the opportunity is taken to clarify what the information on the IUCN Red List represents.  相似文献   

3.
Under the impact of human activity, global extinction rates have risen a thousand times higher than shown in the fossil record. The resources available for conservation are insufficient to prevent the loss of much of the world's threatened biodiversity during this crisis. Conservation planners have been forced to prioritize their protective activities, in the context of great uncertainty. This has become known as 'the agony of choice'. A range of methods have been proposed for prioritizing species for conservation attention; one of the most strongly supported is prioritizing those species that maximize phylogenetic distinctiveness (PD). We evaluate how a composite measure of extinction risk and phylogenetic isolation (EDGE) has been used to prioritize species according to their degree of unique evolutionary history (evolutionary distinctiveness, ED) weighted by conservation urgency (global endangerment, GE). We review PD-based approaches and provide an updated list of EDGE mammals using the 2010 IUCN Red List. We evaluate how robust this method is to changes in phylogenetic uncertainty, knowledge of taxonomy and extinction risk, and examine how mammalian species that rank highly in EDGE score are representative of the collective from which they are drawn.  相似文献   

4.
Current threats to the planet's biodiversity are unprecedented, and they particularly imperil insular floras. In this investigation, we use the threat factors identified by the Millennium Ecosystem Assessment as the main drivers of biodiversity loss on islands to define and rank 13 current, continuing threats to the plant diversity of nine focal archipelagos where volcanic origin (or in the Seychelles a prolonged isolation after a continental origin) has produced a high degree of endemicity and fragility in the face of habitat alteration. We also conduct a global endangerment assessment based on the numbers of insular endemic plants in the endangered (EN) and critically endangered (CR) IUCN categories for 53 island groups with an estimated 9951 endemic plant species, providing a representative sample of the world's insular systems and their floristic richness. Our analyses indicate that isolation does not significantly influence endangerment, but plant endemics from very small islands are more often critically endangered. We estimate that between 3500 and 6800 of the estimated 70,000 insular endemic plant species worldwide might be highly threatened (CR+EN) and between ca. 2000 and 2800 of them in critical danger of extinction (CR). Based on these analyses, and on a worldwide literature review of the biological threat factors considered, we identify challenging questions for conservation research, asking (i) what are the most urgent priorities for the conservation of insular species and floras, and (ii) with the knowledge and assets available, how can we improve the impact of conservation science and practice on the preservation of island biodiversity? Our analysis indicates that the synergistic action of many threat factors can induce major ecological disturbances, leading to multiple extinctions. We review weaknesses and strengths in conservation research and management in the nine focal archipelagos, and highlight the urgent need for conservation scientists to share knowledge and expertise, identify and discuss common challenges, and formulate multi-disciplinary conservation objectives for insular plant endemics worldwide. To our knowledge, this is the most up-to-date and comprehensive survey yet to review the threat factors to native plants on oceanic islands and define priority research questions.  相似文献   

5.
Habitat loss, climate change, over-exploitation, disease and other factors have been hypothesised in the global decline of amphibian biodiversity. However, the relative importance of and synergies among different drivers are still poorly understood. We present the largest global analysis of roughly 45% of known amphibians (2,583 species) to quantify the influences of life history, climate, human density and habitat loss on declines and extinction risk. Multi-model Bayesian inference reveals that large amphibian species with small geographic range and pronounced seasonality in temperature and precipitation are most likely to be Red-Listed by IUCN. Elevated habitat loss and human densities are also correlated with high threat risk. Range size, habitat loss and more extreme seasonality in precipitation contributed to decline risk in the 2,454 species that declined between 1980 and 2004, compared to species that were stable (n = 1,545) or had increased (n = 28). These empirical results show that amphibian species with restricted ranges should be urgently targeted for conservation.  相似文献   

6.
The number of protected areas (PAs) has steadily increased in the past 20 years, but their effectiveness to meet conservation targets is consistently questioned. Most conservation impact evaluations of protected areas assume that formal designations, like that of IUCN categories, reflect site-specific conservation rules, but this is not always true. In this paper we illustrate how conservation rules could be empirically assessed by use of content analysis combined with optimal scaling. This flexible methodology allows us to quantitatively assess strictness levels for use in conservation impact evaluations. The strictness measures could also indicate whether conservation rules are consistently applied in the different IUCN categories thereby providing guidance for future assignment of PAs to the IUCN protected area management categories. We illustrate how policy indicators based on conservation rules could be developed in two contrasting mountain protected area networks in Norway and in British Columbia (BC), including a total of 48 PAs in Norway and 51 in BC. Conservation rules for recreational use, motorized access and resource use were quantitatively assessed, thus providing a measure of how strictly PAs regulate the different human activities. Our results show that the main differences in strictness are between the two countries, followed by the contrast between national parks and provincial parks in BC. Overall, Norway has a more liberal conservation policy than BC and older national parks in BC have a much stricter conservation policy than most of the other PAs in this study. Overarching conservation objectives did not reflect the level of strictness (the conservation rules) that guide the daily management of individual PAs. This applies to both countries. We recommend to empirically investigate site-specific conservation rules to include de facto management of human activities in conservation policy impact evaluations. The methodology is also useful for monitoring downgrading of the protected area status, which is a result of authorizing human activities that are not consistent with conservation objectives.  相似文献   

7.
Marine biodiversity can be protected by identifying vulnerable species and creating marine protected areas (MPAs) to ensure their survival. A wide variety of methods are employed by environmental managers to determine areas of conservation priority, however which methods should be applied is often a subject of debate for practitioners and scientists. We applied two species vulnerability assessments, the International Union for the Conservation of Nature (IUCN) red list of threatened species and FishBase’s intrinsic vulnerability assessment, to fish communities in three coastal habitats (mangrove, rocky and coral) on the island of San Cristobal, Galapagos. When using the IUCN red list of threatened species, rocky reefs hosted the greatest number of vulnerable species, however when applying the FishBase assessment of intrinsic vulnerability mangroves hosted the greatest abundance of ‘very-highly’ vulnerable species and coral ecosystems hosted the greatest abundance of ‘highly’ vulnerable species. The two methods showed little overlap in determining habitat types that host vulnerable species because they rely on different biological and ecological parameters. Since extensive data is required for IUCN red list assessments, we show that the intrinsic vulnerability assessment from FishBase can be used to complement the IUCN red list especially in data-poor areas. Intrinsic vulnerability assessments are based on less data-intensive methods than the IUCN red list, but nonetheless may bridge information gaps that can arise when using the IUCN red list alone. Vulnerability assessments based on intrinsic factors are not widely applied in marine spatial planning, but their inclusion as a tool for forming conservation strategies can be useful in preventing species loss.  相似文献   

8.
The growing demand for natural resources to sustain human population has increased the loss and modification of natural habitats, enhancing the number of species threatened with extinction. Commonly tools such as Red Lists guide conservation actions and policies. However, Red Lists are based in population parameters, and important aspects of biodiversity such as phylogenetic diversity are not considered. Here we evaluated the amount of economic and traditional uses and evolutionary history of palms captured by the global IUCN Red List and the national Red Lists of Colombia and Madagascar. We estimated palms plant use diversity (PUD) and phylogenetic diversity (PD) for all species in the IUCN Red List and for each threat category at global and national scale. We also investigated if the number of uses, PUD and PD predict palm threat level. Species covered by IUCN Red List have lower PUD and PD than expected by chance. At global scale, palms with higher extinction risk have lower number of uses, PUD and PD. However, whereas in Colombia least concern species had lower PUD and PD, in Madagascar only Data Deficient species had lower PUD than expected by chance. Our findings highlight the need of palm specialists to expand the list of palms they have assessed and submit them for inclusion in Red Lists, enabling Red Lists to capture a more random sample of palm evolutionary history and economic uses. That would improve the success of biodiversity conservation actions by taking into account other aspects of biodiversity rather than taxonomic identity.  相似文献   

9.
关于物种濒危等级标准之探讨--对IUCN物种濒危等级的思考   总被引:10,自引:3,他引:7  
为了保存地球上的生物多样性,我们需要根据物种的种群数量与分布、种群数量波动与分布区下降速率来评定濒危物种的濒危等级,并针对物种的濒危等级提出具体的保护措施。1994年11月,IUCN第40次理事会会议正式通过了经过修订的Mace-Lande物种濒危等级标准作为IUCN物种濒危等级标准。IUCN濒危物种红色名录虽然不是国际法和国家法律,但是对于政府间组织、非政府组织的保护决策以及各国的自然法律法规的制定有着深远的影响,在保护生物学理论研究中也发挥了一定作用。我们在研究制定中国水生野生生物濒危等级标准时发现,如果直接应用IUCN物种濒危等级标准评定水生野生生物濒危等级将存在一些问题。如:(1)如何区别对待那些本来就数量稀少、分布区狭窄的物种和那些由于人类活动而导致其种群数量与生境面积急剧下降的物种?(2)不同的动物类群能否应用同一濒危标准尺度?(3)如何区别对待物种边缘分布区和核心分布区的种群数量与密度的差异?(4)如何处理种群的局部灭绝、局部濒危?(5)一些濒危物种在野生环境中濒危,但是这些物种可以人工繁殖,如何处理可以人工繁殖的濒危物种?(6)如果没有种群与栖息地的精确历史资料和统计数据,怎样应用物种的濒危标准评估其濒危等级?在实践中,我们针对这些问题提出了解决方案。考虑与国际流行的IUCN物种濒危等级标准接轨,我们提出来一个由“无危”、“值得关注”、“受胁”、“濒危”和“灭绝”等5个级构成的濒危等级系统,其中“值得关注”、“受胁”、“濒危”又分为“一般”与“高度”两个亚等级。我们提出应区分“生态濒危物种”、“进化濒危物种”;对于不同生物类群,应区分物种的生活史对策,制定不同生活史物种的濒危标准。对于r-对策物种,引入“经济灭绝”这一等级,将这一等级对应于“受胁”等级,以解决缺少物种数量的统计数据和历史数据这一难题;区别对待特有物种,将其濒危等级提升一等;引进集合种群(metapopulation)概念,将集合种群的局域种群(local population)作为“个体”对待。  相似文献   

10.
朱超  方颖  周可新  穆少杰  蒋金亮 《生态学报》2015,35(9):2826-2836
生物多样性为人类提供了生存所必需的一系列生态系统服务和功能。然而,由于人为活动的加剧,生物多样性不断丧失。传统的生物多样性保护主要关注物种多样性,存在着对生物多样性的代表性不足,不能及时反应生态系统多样性的变化等缺点。近年来,生态系统层次上的多样性保护成为研究热点,一些国家和组织相继开展了大尺度的生态系统评估工作。文章回顾了已有的生态系统评估方案,发现当前生态系统评估多采用IUCN物种红色名录的分级标准体系,主要评估生态系统的濒危程度,评估标准主要是分布范围和功能的变化,不同评估方案采用的指标和阈值有差异,需要建立统一的生态系统分类体系和评价方案。同时,结合国内生态系统评价的现状,提出了在我国开展生态系统红色名录研究的若干可行建议。  相似文献   

11.
Protected areas are critical for the conservation of many threatened species. Despite this, many protected areas are acutely underfunded, which reduces their effectiveness significantly. Tourism is one mechanism to promote and fund conservation in protected areas, but there are few studies analyzing its tangible conservation outcomes for threatened species. This study uses the 415 IUCN critically endangered frog species to evaluate the contribution of protected area tourism revenue to conservation. Contributions were calculated for each species as the proportion of geographic range inside protected areas multiplied by the proportion of protected area revenues derived from tourism. Geographic ranges were determined from IUCN Extent of Occurrence maps. Almost 60% (239) of critically endangered frog species occur in protected areas. Higher proportions of total range are protected in Nearctic, Australasian and Afrotopical regions. Tourism contributions to protected area budgets ranged from 5–100%. These financial contributions are highest for developing countries in the Afrotropical, Indomalayan and Neotropical regions. Data for both geographic range and budget are available for 201 critically endangered frog species with proportional contributions from tourism to species protection ranging from 0.8–99%. Tourism''s financial contributions to critically endangered frog species protection are highest in the Afrotropical region. This study uses a coarse measure but at the global scale it demonstrates that tourism has significant potential to contribute to global frog conservation efforts.  相似文献   

12.
13.
Recent assessments by the International Union for Conservation of Nature (IUCN) indicate the existence of about 612 recognized primate species and subspecies (IUCN RedList, 2012), but close to 50% of these taxa are at risk of extinction as a result of human action. In this article, I call attention to underlying regional and global socioeconomic contexts of primate conservation. Using information from FAO and UN databases and other sources, I examine, for the Neotropics, sub‐Saharan Africa, and Southeast Asia, trends in forest loss and human demographics and social condition, discuss the impact of global market pressures upon primate habitats, and examine land‐use patterns that may favor primate conservation. Between 1990 and 2010, an estimated 149 million ha of forest were lost in the three regions and additional losses are expected in the future. Global human population will increase from 7 billion in 2012 to 9 billion in 2050. Currently, 2 billion people live in the three primate range regions under high levels of poverty. Large‐scale deforestation is related to global market demands, especially from developed and developing nations, for food (e.g., cattle), domestic animal feed (e.g., soybeans), biofuel‐based crops (e.g., oil palm), and industrial round wood. The growth of protected areas in the three regions has been steady for several decades, but it is not enough to ensure long‐term conservation of many primate taxa. Other conservations tools involving sustainable land use and biodiversity conservation corridors are required at the landscape level. The above assessment can easily be applied at the local level by primatologists, giving more precision to conservation initiatives. Am. J. Primatol. 75:30‐45, 2013. © 2012 Wiley Periodicals, Inc.  相似文献   

14.
Table Mountain maintained internationally high global conservation priority with respect to the aquatic Coleoptera. The study site displayed an overall 77% endemism with 65% of species provisionally of high IUCN international conservation status. Reservoirs were shown to have a dramatic negative impact on the endemic and endangered water beetles of Table Mountain. This comprised of an overall species loss of 73%, all endemics, and a 64% loss of high conservation status species in the Hydraenidae, Dryopidae and Elmidae. Further hydrological alteration in the region was not recommended and the necessary inclusion of water beetles in future EIA assessments stipulated. The necessity for bioinventory methodology in addition to standard netting methodology was conclusively illustrated. A Balanced Scorecard approach to conservation decisions based on species level data including appropriate bioinventory survey methodology, recent survey data, IUCN status, and levels of endemism was proposed. The differentiation of species communities with altitude produced a division between upland and lowland communities on Table Mountain. Distinct differences between the reservoir impacted and natural upland water beetle communities were demonstrated.  相似文献   

15.
The IUCN Red List of Threatened Animals is an important conservation tool, but the accuracy of predictions about risks of global extinction within 10 years or three generations is difficult to test objectively. In this study, we compare IUCN predictions with the results of attempts to derive realistic scenarios that could lead to the global extinction of six species of long-lived reptiles. For three species, the IUCN predictions matched real events reasonably well but still overestimated risks of global extinction. For the other species, the predictions did not match real events. Reasons why disparities occur are discussed. Received: February 16, 1999 / Accepted: December 27, 1999  相似文献   

16.
The huge conservation interest that mammals attract and the large datasets that have been collected on them have propelled a diversity of global mammal prioritization schemes, but no comprehensive global mammal conservation strategy. We highlight some of the potential discrepancies between the schemes presented in this theme issue, including: conservation of species or areas, reactive and proactive conservation approaches, conservation knowledge and action, levels of aggregation of indicators of trend and scale issues. We propose that recently collected global mammal data and many of the mammal prioritization schemes now available could be incorporated into a comprehensive global strategy for the conservation of mammals. The task of developing such a strategy should be coordinated by a super-partes, authoritative institution (e.g. the International Union for Conservation of Nature, IUCN). The strategy would facilitate funding agencies, conservation organizations and national institutions to rapidly identify a number of short-term and long-term global conservation priorities, and act complementarily to achieve them.  相似文献   

17.
In the face of accelerating species extinctions, map-based prioritization systems are increasingly useful to decide where to pursue conservation action most effectively. However, a number of seemingly inconsistent schemes have emerged, mostly focussing on endemism. Here we use global vertebrate distributions in terrestrial ecoregions to evaluate how continuous and categorical ranking schemes target and accumulate endangered taxa within the IUCN Red List, Alliance for Zero Extinction (AZE), and EDGE of Existence programme. We employed total, endemic and threatened species richness and an estimator for richness-adjusted endemism as metrics in continuous prioritization, and WWF''s Global200 and Conservation International''s (CI) Hotspots in categorical prioritization. Our results demonstrate that all metrics target endangerment more efficiently than by chance, but each selects unique sets of top-ranking ecoregions, which overlap only partially, and include different sets of threatened species. Using the top 100 ecoregions as defined by continuous prioritization metrics, we develop an inclusive map for global vertebrate conservation that incorporates important areas for endemism, richness, and threat. Finally, we assess human footprint and protection levels within these areas to reveal that endemism sites are more impacted but have more protection, in contrast to high richness and threat ones. Given such contrasts, major efforts to protect global biodiversity must involve complementary conservation approaches in areas of unique species as well as those with highest diversity and threat.  相似文献   

18.
European nature conservation documents, often reflect the charisma of a species rather than its actual degree of threat. The assessment of the threat status of 14 endemic Sardinian butterfly species, underlines that European nature legislation documents are incomplete. Pseudophilotes barbagiae and Lysandra coridon gennargenti (Lycaenidae) are identified as globally Vulnerable and are therefore proposed to be added to the Red Data Book of European butterflies as species of global conservation concern. A threat factor analysis identifies risks towards butterflies in Sardinia arising from increasing human activities. It is shown how the quantitative information used by the IUCN criteria, together with a qualitative assessment of human induced threat factors, could be combined to produce an objective standardised assessment that can be used also when only data on present distribution are available. Threats to Sardinian butterflies are highlighted and conservation measures proposed. The inclusion of Pseudophilotes barbagiae and Lysandra coridon gennargenti in Annex II and IV of the European Habitats Directive, and in Appendix II of the Bern Convention, is strongly recommended.  相似文献   

19.
Land use change alters species' abundance and distributions by affecting habitat availability and quality. The decline of bird populations worldwide is of major concern, and habitat protection and restoration are primary conservation actions. However, conservation decisions largely consider only short-term habitat changes and species’ population dynamics in a given area. Disregarding long term modifications in species’ available habitat, and the role of a given population for a species’ global population may lead to misdirected conservation action. Our goal here was to combine the assessment of conservation responsibility, with that of century-long available habitat dynamics, in order to inform better conservation practice. We compiled available habitat data for 170 bird species in the Carpathian Region from 1860 to 2010 from historic maps and satellite data. We analyzed these species’ range distributions, IUCN extinction risk and population trends, and we identified 29 species of high conservation responsibility, and all of them were forest or and grassland specialists. Furthermore, we found major land use trends including cropland abandonment and increase in forests and grasslands that resulted in increases in potential habitat for the species for which the Carpathians have high conservation responsibility. The loss of row-crop agriculture, on the other hand, reduced habitat for species for which the Carpathians do not have high responsibility, and thus subsidizing agriculture may not be warranted from a conservation perspective. More broadly, many regions worldwide are undergoing rapid land use changes, and we suggest that these should be analyzed relative to a given regions’ conservation responsibility to see if there are opportunities for conservation, i.e., cases similar to the Carpathians, where conservation efforts ‘only’ have to foster current land use trends, and make them permanent, rather than to try to revert the loss of habitat.  相似文献   

20.
The cornerstone of EU nature conservation, the Natura 2000 (N2K) network is far from complete in many EU countries, including Cyprus, particularly where new datasets have become available. Thus, an important question in conservation biology is how new data can be incorporated in an effort to redesign N2K where appropriate. We analyse the efficacy of the N2K network in Cyprus, a global biodiversity hotspot, for protecting threatened vascular plants. We used 252 species for which detailed distributional data were available and added new records for 168 species. Overlaying a 1 km2 grid map for Cyprus we identified distributional hotspots of threatened species (sensu IUCN) and assessed their representation level within the N2K network. Based on new recorded data we propose IUCN status changes for 15 species. There were 60 hotspots identified (cells with more than 5 threatened species) in the central-west, south, southeast and north parts of the island. GIS analysis demonstrated that 145 out of 252 species (57.5%) occur within the N2K network, ranging from 4 to 100% of their occurrences. Τhe conservation gaps identified are related to 107 threatened species (42.5% of Red Data Book plants) which are either completely outside the N2K network or in those areas where EU legislation is not applicable due to the complex political situation on the island. The most important conservation opportunities are found in the northern part of the island, where the acquis communautaire is suspended and the UK Sovereign Base Areas, which are excluded from the Accession Treaty of Cyprus. In the area under the effective control of the Government of the Republic of Cyprus (CYGCA) there are only two important hotspots found outside the N2K network.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号