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1.
Trinidad and Tobago are home to three endemic species in the anuran genus Pristimantis, of which two (Pristimantis charlottevillensis and Pristimantis turpinorum) occur in Tobago alone and the third (Pristimantis urichi) is present on both islands. Earlier, the IUCN assessed the conservation status of these species as: P. urichi, Endangered (EN); P. charlottevillensis, Least Concern (LC); P. turpinorum, Vulnerable (VU). However, these assessments were based on very little field-based evidence. Here, we present survey results which contributed to reassessments as LC, VU and Data Deficient for these three species, respectively. Despite the close proximity of Trinidad to northern Venezuela, the islands do not share any Pristimantis species with the mainland, which holds a rich endemicity of Pristimantis regionally. In this study, we used genetic sequencing from several island populations and compared them to northern Venezuelan endemics to assess genetic divergence for the first time. The time tree analyses found that only the northern Tobago species P. turpinorum is closely related to mainland Pristimantis, with a genetic split dating to the Late Miocene, suggesting a vicariant event of mainland and island species. Pristimantis urichi, although identical between the two islands, remains highly divergent from the mainland species. Similar results were found for P. charlottevillensis. In addition, there was a high level of divergence between P. urichi and P. charlottevillensis. These findings indicate different island colonization events by different lineages. Sequencing other Venezuelan species remains pivotal to unravel the complexity of the colonization episodes in the region, likely influenced by the changing topography and multiple connection and isolation episodes of the islands by eustatic sea-level changes.  相似文献   

2.
江苏珍稀濒危植物的多样性、分布及保护   总被引:1,自引:0,他引:1  
掌握重点保护野生植物的濒危现状及评估濒危等级是制定科学保护策略的关键。根据江苏第二次重点保护野生植物资源调查(2012-2018)以及近年来相关调查资料, 我们采用世界自然保护联盟(IUCN)物种红色名录的濒危等级与评估标准, 对江苏分布的珍稀濒危植物的现状与濒危等级进行了评估与分析。结果表明: (1)江苏41种国家重点保护和濒危野生植物的濒危等级可以分为7个等级。包括地区灭绝(RE) 2种, 占总种数的4.88%; 极危(CR) 10种, 占24.39%; 濒危(EN) 6种, 占14.63%; 易危(VU) 13种, 占31.71%; 近危(NT) 2种, 占4.88%; 无危(LC) 2种, 占4.88%; 数据缺乏(DD) 6种, 占14.63%。其中, 受威胁物种(包括CR、EN和VU)有29种, 占总种数的70.73%。(2)建议的江苏重点保护野生植物有74种, 隶属于40科62属; 它们的受威胁比例较高, 达74.32%。江苏人口众多、环境资源压力较大, 近年来生产经营和土地利用方式的改变以及宣传教育不足很可能是导致这些原生物种濒危的主要原因。因此建议: (1)尽快制定江苏省级重点保护野生植物名录; (2)加强科学研究, 同时对部分濒危植物进行就地保护和迁地保护, 积极开展野外回归、近地保护和动态监测; (3)继续加大对重点保护野生植物的保护管理和宣传力度。  相似文献   

3.
Understanding changes in abundance is crucial for conservation, but population growth rates often vary over space and time. We use 40 years of count data (1979–2019) and Bayesian state‐space models to assess the African penguin Spheniscus demersus population under IUCN Red List Criterion A. We deconstruct the overall decline in time and space to identify where urgent conservation action is needed. The global African penguin population met the threshold for Endangered with a high probability (97%), having declined by almost 65% since 1989. An historical low of ~17,700 pairs bred in 2019. Annual changes were faster in the South African population (?4.2%, highest posterior density interval, HPDI: ?7.8 to ?0.6%) than the Namibian one (?0.3%, HPDI: ?3.3 to +2.6%), and since 1999 were almost ?10% at South African colonies north of Cape Town. Over the 40‐year period, the Eastern Cape colonies went from holding ~25% of the total penguin population to ~40% as numbers decreased more rapidly elsewhere. These changes coincided with an altered abundance and availability of the main prey of African penguins. Our results underline the dynamic nature of population declines in space as well as time and highlight which penguin colonies require urgent conservation attention.  相似文献   

4.
基于标本和分布信息评估中国虾脊兰属 植物的濒危状况   总被引:1,自引:0,他引:1  
兰科植物是生物多样性保护的旗舰类群之一, 但如何客观准确地评估兰科植物的濒危状况, 一直是生物多样性保护中急需解决的问题。本文以中国虾脊兰属(Calanthe)植物为例, 探讨了基于馆藏标本和野外分布信息进行兰科植物红色名录濒危等级评估的利弊。我们的研究表明, 馆藏标本能够比较客观地反映物种地理分布信息和相应的野外居群状况, 但对于物种分布的历史变化和受威胁因素反映不足; 而野外工作对于物种的实际分布状况和受威胁因素等的反映比较客观, 但能发现的物种和居群数量有限, 部分极小种群物种在短时间野外工作中很难发现。我们的研究认为, 有2种虾脊兰属植物应被评估为野外灭绝(EW), 16种应被评估为极度濒危(CR)。可见, 中国虾脊兰属植物濒危的状况远比前人的评估结果要严重得多。  相似文献   

5.
6.
In vertebrates, large body size is often a key diagnostic feature of species threatened with extinction. However, in amphibians the link between body size and extinction risk is highly uncertain, with previous studies suggesting positive, negative, u-shaped, or no relationship. Part of the reason for this uncertainty is ‘researcher degrees of freedom’: the subjectivity and selectivity in choices associated with specifying and fitting models. Here, I clarify the size–threat association in amphibians using Specification Curve Analysis, an analytical approach from the social sciences that attempts to minimize this problem by complete mapping of model space. I find strong support for prevailing negative associations between body size and threat status, the opposite of patterns typical in other vertebrates. This pattern is largely explained by smaller species having smaller geographic ranges, but smaller amphibian species also appear to lack some of the life-history advantages (e.g. higher reproductive output) that are often assumed to ‘protect’ small species in other taxa. These results highlight the need for a renewed conservation focus on the smallest species of the world''s most threatened class of vertebrates, as aquatic habitats become increasingly degraded by human activity.  相似文献   

7.
On oceanic islands, the evolution of plants and animals with particular characteristics is favoured due to their isolation, populations normally comprising a large number of unique, endemic species. The Madeira and Selvagens archipelagos are considered biodiversity hotspots, containing an especially rich bryoflora. Due to its characteristically small size, this taxonomic group does not get much attention in conservation programmes. However, these plants are an important component of terrestrial ecosystems, representing a major part of biodiversity and playing a vital role in the ecosystem's functioning. As such, the development of the first Red List for Madeira and Selvagens Archipelagos has the potential to guide conservation efforts focused on taxa and habitats where threatened species and endemics are better represented. By applying the International Union for Conservation of Nature and Natural Resources (IUCN) criteria, recently revised to apply to small islands, it was possible to obtain the percentage of threatened taxa present in the archipelagos (23.6%), and for each habitat type. It was verified that high mountain habitats and the Laurel forest represent areas that host higher percentages of threatened taxa (29.5% and 22.2%). An important result of the present Red List is the identification of hotspots for bryophyte diversity, supporting the definition of reserves/microreserves. The information obtained can also be linked up with the Red Lists of other taxonomic groups to work towards the definition of a more holistic conservation strategy.  相似文献   

8.
Many organisms migrate between distinct habitats, exploiting variable resources while profoundly affecting ecosystem services, disease spread, and human welfare. However, the very characteristics that make migration captivating and significant also make it difficult to study, and we lack a comprehensive understanding of which species migrate and why. Here we show that, among mammals, migration is concentrated within Cetacea and Artiodactyla but also diffusely spread throughout the class (found in 12 of 27 orders). We synthesize the many ecological drivers of round‐trip migration into three types of movement—between breeding and foraging sites, between breeding and refuge sites, and continuous tracking of forage/prey—each associated with different traits (body mass, diet, locomotion, and conservation status). Our results provide only partial support for the hypothesis that migration occurs without phylogenetic constraint. Furthermore, our findings suggest that categorizing migration into these three types may aid predictions of migrants’ responses to environmental changes.  相似文献   

9.
The aim of this study was to assess trends in captive breeding of threatened and endangered bird species in British zoos. The measures we recorded were: 1) the total number of species held, 2) the percentage of species held that are listed in the IUCN Red List, 3) the percentage of endangered species breeding, and 4) the number of species in managed breeding programs. These data were gathered from the bird inventories of 10 representative British zoos for the years 1988 and 1997. The data for measures 1–3 were compared between the 2 years using a Wilcoxon matched‐pairs test. We found that the zoos maintained the same number of species (W=10.5; n=10; P=0.093; median=87.5 and 78 for 1988 and 1997, respectively). However, there was a significant increase in the number of birds held that fit each of the IUCN's conservation categories (Endangered: W=43.0; n=10; P<0.05, median=1.48 and 6.64 for 1988 and 1997, respectively; Vulnerable: W=53.0; n=10; P<0.05, median=3.33 and 10.05 for 1988 and 1997, respectively; and Rare: W=55.0; n=10; P<0.01, median=0.00 and 8.33 for 1988 and 1997, respectively). Overall, the percentage of threatened species kept in zoos increased from a median of 4.81 in 1988 to 25.02 in 1997. During this period there was an increase in the number of species in each category of the IUCN Red List. No difference was found in the number of threatened species breeding between 1988 and 1997. Zoo Biol 23:85–89, 2004. © 2004 Wiley‐Liss, Inc.  相似文献   

10.
The Sungazer (Smaug giganteus) is a threatened lizard species endemic to the Highveld grasslands of South Africa. The species faces risks from habitat loss and fragmentation, and illegal harvesting for traditional medicine and the pet trade. Despite these threats, the current conservation status of the species was poorly validated. We visited 79 Sungazer populations recorded in 1978 to assess population change since the initial surveys, and surveyed an additional 164 sites to better define the distribution and estimate the current population size. We interrogated all known historical trade data of the species. One-third of Sungazer populations have been extirpated over the past 37 years. The distribution includes two allopatric populations, with the smaller Mpumalanga population experiencing a significantly higher decline. The species has an extent of occurrence (EOO) of 34 500 km2, and an area of occupancy (AOO) of 1149 km2. The interpreted distribution is 17 978 km2, and just under 60% remains untransformed grassland. We estimate a population size of 677 000 mature individuals, down 48% from the estimated historical population, prior to commercial agricultural development. A total of 1194 live Sungazers were exported under permit from South Africa between 1985 and 2014, with a significant increase in numbers exported over the last decade. Without any evidence of captive breeding, we believe that these animals are all wild-caught. Based on the AOO, level of decline, fragmentation within the distribution and suspected level of exploitation, we recommend classification of the species as Vulnerable under IUCN Red List Criteria A2acd and B2ab(ii–v). The establishment of a protected area network, genetic research and further investigations into the pet and traditional medicine trades are urgently needed.  相似文献   

11.
12.
A recent complete assessment of the conservation status of 5487 mammal species demonstrated that at least one-fifth are at risk of extinction in the wild. We retrospectively identified genuine changes in extinction risk for mammals between 1996 and 2008 to calculate changes in the International Union for Conservation of Nature (IUCN) Red List Index (RLI). Species-level trends in the conservation status of mammalian diversity reveal that extinction risk in large-bodied species is increasing, and that the rate of deterioration has been most accelerated in the Indomalayan and Australasian realms. Expanding agriculture and hunting have been the main drivers of increased extinction risk in mammals. Site-based protection and management, legislation, and captive-breeding and reintroduction programmes have led to improvements in 24 species. We contextualize these changes, and explain why both deteriorations and improvements may be under-reported. Although this study highlights where conservation actions are leading to improvements, it fails to account for instances where conservation has prevented further deteriorations in the status of the world's mammals. The continued utility of the RLI is dependent on sustained investment to ensure repeated assessments of mammals over time and to facilitate future calculations of the RLI and measurement against global targets.  相似文献   

13.
A taxonomic revision of the genus Flagenium Baill. is presented. Flagenium is endemic to Madagascar and comprises six species; three new species are described here ( F. farafanganensis , F. petrikensis , and F. pedunculatum ) and one species ( F. arboreum ) is transferred into synonymy. Each species is fully described, and summaries of distribution, habitat and ecology, and phenology are given; conservation assessments are provided for each species. Flagenium is characterized by having ovaries with at least two erect and two pendulous ovules per locule, which, depending on the species, can display an additional two to four horizontal ovules per locule arranged between the uppermost and lowermost ovules. In addition, Flagenium has a longitudinally ten-ribbed fruit. These features are potentially unique within the Octotropideae.  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 155 , 557–570.  相似文献   

14.
Sawfishes are among the most endangered of all elasmobranch species, a factor fostering considerable worldwide interest in the conservation of these animals. However, conservation efforts have been hampered by the confusing taxonomy of the group and the poor state of knowledge about the family's geographical population structure. Based on historical taxonomy, external morphology, and mitochondrial DNA sequences (NADH‐2), we show here that, globally, the sawfish comprise five species in two genera: Pristis pristis (circumtropical), Pristis clavata (east Indo‐West Pacific), Pristis pectinata (Atlantic), Pristis zijsron (Indo‐West Pacific), and Anoxypristis cuspidata (Indo‐West Pacific, except for East Africa and the Red Sea). This improved understanding will have implications for the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), International Union for Conservation of Nature (IUCN) Red List assessments, and endangered species laws and regulations in several countries. Furthermore, based on both or either of NADH‐2 and the number of rostral teeth per side, we show that populations of P. pristis, P. pectinata, P. zijsron, and A. cuspidata exhibit significant geographic structuring across their respective ranges, meaning that regional‐level conservation will be required. Finally, the NADH‐2 gene may serve as a marker for the identification of rostra and fins involved in illegal trade. © 2012 The Linnean Society of London  相似文献   

15.
Conservation status, identification, distribution, abundance, habitat and ecology, threats, conservation actions and recommendations of an endemic catfish, King’s bullhead, Silurus mento were introduced.  相似文献   

16.
17.
Summary

Stipitate hydnoid (‘tooth’) fungi are considered to be threatened throughout much of central and northern Europe. In response to concern about the status of these fungi in the UK, a Biodiversity Action Plan has been developed for 14 species in this group. As a first step towards implementation of this plan, a number of surveys have been initiated, to determine the current status and distribution of hydnoid fungi. An overview of the results of these surveys is described. A series of distribution maps are presented, based on a compilation of early records and the results of a recent field survey in Scottish coniferous forests. The difficulties of interpreting early records are discussed, with particular reference to the taxonomie confusion that has surrounded this group of fungi. Although available data provide little evidence for decline of hydnoid fungi, a number of species display very restricted distributions within Scotland. The recent discovery of several species new to Britain emphasises the need for further field surveys to define the current status of these fungi with greater accuracy.  相似文献   

18.
Decline in the populations of bumble bees and other pollinators stress the need for more knowledge about their conservation status. Only one of the 25 bumble bee species present in Hungary is included in the Hungarian Red List. We estimated the endangerment of the Hungarian bumble bee (Bombus Latr.) species using the available occurrence data from the last 50 years of the 20th century. Four of the 25 species were data deficient or extinct from Hungary. About 60% of species were considered rare or moderately rare. Changes in distribution and occurrence frequency indicated that 10 of the 21 native species showed a declining trend, while only three species increased in frequency of occurrence. According to the IUCN Red List categories, seven species (33% of the native fauna) should be labelled as critically endangered (CR) and 3 (14%) as endangered (EN). Our results stress an urgent need of protection plans for bumble bees in Hungary, and further underlines the validity of concern over bumble bees all over Europe.  相似文献   

19.
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.  相似文献   

20.
The Cape Gannet Morus capensis is one of several seabird species endemic to the Benguela upwelling ecosystem (BUS) but whose population has recently decreased, leading to an unfavourable IUCN Red List assessment. Application of ‘JARA’ (‘Just Another Red-List Assessment,’ a Bayesian state-space tool used for IUCN Red List assessments) to updated information on the areas occupied by Cape Gannets and the nest densities of breeding birds at their six colonies, suggested that the species should be classified as Vulnerable. However, the rate of decrease of Cape Gannets in their most-recent generation exceeded that of the previous generation, primarily as a result of large decreases at Bird Island, Lambert’s Bay, and Malgas Island, off South Africa’s west coast (the western part of their range). Since the 1960s, there has been an ongoing redistribution of the species from northwest to southeast around southern Africa, and ~70% of the population now occurs on the south coast of South Africa, at Bird Island in Algoa Bay, on the eastern border of the BUS. Recruitment rather than adult survival may be limiting the present population; however, information on the seabird’s demographic parameters and mortality in fisheries is lacking for colonies in the northern part of the BUS. Presently, major threats to Cape Gannet include: substantially decreased availability of their preferred prey in the west; heavy mortalities of eggs, chicks and fledglings at and around colonies, inflicted by Cape Fur Seals Arctocephalus pusillus and other seabirds; substantial disturbance at colonies caused by Cape Fur Seals attacking adult gannets ashore; oiling; and disease.  相似文献   

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