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.
Red List Indices provide a method for assessing global trends in species?? conservation status, and for monitoring progress towards achieving conservation targets (for example, commitments under the Convention on Biological Diversity). Red List Indices are based on categorization of taxa in terms of their threat status using information on, for example, current and projected abundances, distributions, and threats. Global assessments have now been undertaken for a suite of well-known vertebrate taxa. However, highly diverse invertebrate taxa are currently very poorly represented in such assessments, and there is a danger that their threats and their utility as biodiversity indicators will be overlooked. Unlike most invertebrates, butterflies are relatively well-known globally. We describe ongoing efforts to incorporate butterflies into the Red List Index process. Because of high species richness (approximately 15,000 Papilionoidea globally) a comprehensive assessment is not feasible. Instead, we apply a ??Sampled Red List Index?? approach which draws on a subset of 1,500 focal taxa. We illustrate the process and the challenges (particularly taxonomic issues and issues of data deficiency) using a variety of case studies. The information provided should be relevant to other researchers seeking to apply the Red List Index approach to invertebrates and other diverse but poorly studied taxa.  相似文献   

2.
Using spatial predictions of future threats to biodiversity, we assessed for the first time the relative potential impacts of future land use and climate change on the threat status of plant species. We thus estimated how many taxa could be affected by future threats that are usually not included in current IUCN Red List assessments. Here, we computed the Red List status including future threats of 227 Proteaceae taxa endemic to the Cape Floristic Region, South Africa, and compared this with their Red List status excluding future threats. We developed eight different land use and climate change scenarios for the year 2020, providing a range of best‐ to worst‐case scenarios. Four scenarios include only the effects of future land use change, while the other four also include the impacts of projected anthropogenic climate change (HadCM2 IS92a GGa), using niche‐based models. Up to a third of the 227 Proteaceae taxa are uplisted (become more threatened) by up to three threat categories if future threats as predicted for 2020 are included, and the proportion of threatened Proteaceae taxa rises on average by 9% (range 2–16%), depending on the scenario. With increasing severity of the scenarios, the proportion of Critically Endangered taxa increases from about 1% to 7% and almost 2% of the 227 Proteaceae taxa become Extinct because of climate change. Overall, climate change has the most severe effects on the Proteaceae, but land use change also severely affects some taxa. Most of the threatened taxa occur in low‐lying coastal areas, but the proportion of threatened taxa changes considerably in inland mountain areas if future threats are included. Our approach gives important insights into how, where and when future threats could affect species persistence and can in a sense be seen as a test of the value of planned interventions for conservation.  相似文献   

3.
Temperate grasslands have suffered disproportionally from conversion to cropland, degradation and fragmentation. A large proportion of the world’s remaining near-natural grassland is situated in Kazakhstan. We aimed to assess current and emerging threats to steppe and semi-desert biodiversity in Kazakhstan and evaluate conservation research priorities. We conducted a horizon-scanning exercise among conservationists from academia and practice. We first compiled a list of 45 potential threats. These were then ranked by the survey participants according to their perceived severity, the need for research on them, and their novelty. The highest-ranked threats were related to changes in land use (leading to habitat loss and deterioration), direct persecution of wildlife, and rapid infrastructure development due to economic and population growth. Research needs were identified largely in the same areas, and the mean scores of threat severity and research need were highly correlated. Novel threats comprised habitat loss by photovoltaic and wind power stations, climate change and changes in agriculture such as the introduction of biofuels. However, novelty was not correlated with threat severity or research priority, suggesting that the most severe threats are the established ones. Important goals towards more effective steppe and semi-desert conservation in Kazakhstan include more cross-sector collaboration (e.g. by involving stakeholders in conservation and agriculture), greater allocation of funds to under-staffed areas (e.g. protected area management), better representativeness and complementarity in the protected area system and enhanced data collection for wildlife monitoring and threat assessments (including the use of citizen-science databases).  相似文献   

4.
5.
Global conservation priorities for marine turtles   总被引:2,自引:0,他引:2  
Where conservation resources are limited and conservation targets are diverse, robust yet flexible priority-setting frameworks are vital. Priority-setting is especially important for geographically widespread species with distinct populations subject to multiple threats that operate on different spatial and temporal scales. Marine turtles are widely distributed and exhibit intra-specific variations in population sizes and trends, as well as reproduction and morphology. However, current global extinction risk assessment frameworks do not assess conservation status of spatially and biologically distinct marine turtle Regional Management Units (RMUs), and thus do not capture variations in population trends, impacts of threats, or necessary conservation actions across individual populations. To address this issue, we developed a new assessment framework that allowed us to evaluate, compare and organize marine turtle RMUs according to status and threats criteria. Because conservation priorities can vary widely (i.e. from avoiding imminent extinction to maintaining long-term monitoring efforts) we developed a “conservation priorities portfolio” system using categories of paired risk and threats scores for all RMUs (n = 58). We performed these assessments and rankings globally, by species, by ocean basin, and by recognized geopolitical bodies to identify patterns in risk, threats, and data gaps at different scales. This process resulted in characterization of risk and threats to all marine turtle RMUs, including identification of the world''s 11 most endangered marine turtle RMUs based on highest risk and threats scores. This system also highlighted important gaps in available information that is crucial for accurate conservation assessments. Overall, this priority-setting framework can provide guidance for research and conservation priorities at multiple relevant scales, and should serve as a model for conservation status assessments and priority-setting for widespread, long-lived taxa.  相似文献   

6.
The paper attempts to describe Italian mammal diversity in an evolutionary context. With 122 species according latest researches, Italy holds the richest mammal assemblage among European countries. Specific taxa are often represented by clearly distinctive lineages and several of them appear restricted to the Italian peninsula. Poor knowledge of taxonomy and uncritical application of IUCN threat categories at the national level could produce a flawed set of conservation priorities, independently from the rigorous application of the proposed guidelines for national Red List assessments. Furthermore, classical conservation assessments and protective legislation only consider traditionally named taxa, often privileging insular taxa of artificial origin but neglecting most of the results of genetic and molecular studies on intraspecific variation. The aim of the present work is to outline the need to incorporate phylogenetic and biogeographic data in the assessment of conservation priorities among mammals in Italy, in order to maximise the national contribution to biodiversity conservation in Europe. To this end, distribution, threat status, intraspecific and supraspecific taxonomy of the native mammal fauna should be analysed in a global context. Phylogeographic patterns emerging from previous studies indicate the general inadequacy of continental European populations serving as sources for re-stocking or re-introductions operations in Italy and the other European peninsulas. Thus the importance of integrating international guidelines on reintroductions with a clear understanding of national biogeographical peculiarities is highlighted.  相似文献   

7.
Refugia have been suggested as priority sites for conservation under climate change because of their ability to facilitate survival of biota under adverse conditions. Here, we review the likely role of refugial habitats in conserving freshwater biota in arid Australian aquatic systems where the major long‐term climatic influence has been aridification. We introduce a conceptual model that characterizes evolutionary refugia and ecological refuges based on our review of the attributes of aquatic habitats and freshwater taxa (fishes and aquatic invertebrates) in arid Australia. We also identify methods of recognizing likely future refugia and approaches to assessing the vulnerability of arid‐adapted freshwater biota to a warming and drying climate. Evolutionary refugia in arid areas are characterized as permanent, groundwater‐dependent habitats (subterranean aquifers and springs) supporting vicariant relicts and short‐range endemics. Ecological refuges can vary across space and time, depending on the dispersal abilities of aquatic taxa and the geographical proximity and hydrological connectivity of aquatic habitats. The most important are the perennial waterbodies (both groundwater and surface water fed) that support obligate aquatic organisms. These species will persist where suitable habitats are available and dispersal pathways are maintained. For very mobile species (invertebrates with an aerial dispersal phase) evolutionary refugia may also act as ecological refuges. Evolutionary refugia are likely future refugia because their water source (groundwater) is decoupled from local precipitation. However, their biota is extremely vulnerable to changes in local conditions because population extinction risks cannot be abated by the dispersal of individuals from other sites. Conservation planning must incorporate a high level of protection for aquifers that support refugial sites. Ecological refuges are vulnerable to changes in regional climate because they have little thermal or hydrological buffering. Accordingly, conservation planning must focus on maintaining meta‐population processes, especially through dynamic connectivity between aquatic habitats at a landscape scale.  相似文献   

8.
The immediacy of conservation decisions for imperiled species often requires rapid assessments of fundamental species-specific data to appropriately guide conservation resources, regulatory actions, and mitigation activities. The goal of this paper was to inform future conservation and management decisions for the imperiled Carson Valley silverspot butterfly (Speyeria nokomis carsonensis), a species that has been subject to conservation attention, yet very little is known about its distribution and habitat. Surveys for S. nokomis carsonensis and its habitat were conducted during 2004–2005. An 88% decline in the number of historic subpopulations was observed, but 30 new subpopulations were discovered. Among the 62 sites that either had populations or were considered potentially suitable habitat, three distinct habitat types were delineated: agricultural seeps, isolated springs, and riparian meadows. Riparian sites comprised 58% of all sites and little variation was observed in the proportion of occupancy across habitat types. Disturbance was substantially greater in unoccupied sites than in sites occupied by S. nokomis carsonensis. Livestock grazing was the primary threat (50% of sites) to habitat, while water diversions were a secondary threat (7 sites). The variability in habitat and threats identifies that even for highly specialized subspecies, all habitats simply cannot be considered equal candidates for inclusion in a conservation strategy for the butterfly. Adopting proactive management policies that conserve suites of sites within each habitat type and reduce grazing intensity within S. nokomis carsonensis habitats should be a priority to reduce threats and circumvent a prospective listing pursuant to the US Endangered Species Act.  相似文献   

9.
We compile a Mexican insular herpetofaunal checklist to estimate endemism, conservation status, island threats, net taxonomic turnover among six biogeographic provinces belonging to the Nearctic and Neotropical regions, and the relationships between island area and mainland distance versus species richness. We compile a checklist of insular herpetofaunal through performing a literature and collection review. We define the conservation status according to conservation Mexican law, the Red List of International Union for Conservation of Nature, and Environmental Vulnerability Scores. We determine threat percentages on islands according to the 11 major classes of threats to biodiversity. We estimate the net taxonomic turnover with beta diversity analysis between the Nearctic and Neotropical provinces. The Mexican insular herpetofauna is composed of 18 amphibian species, 204 species with 101 subspecies of reptiles, and 263 taxa in total. Endemism levels are 11.76% in amphibians, 53.57% in reptiles, and 27.91% being insular endemic taxa. Two conservation status systems classify the species at high extinction risk, while the remaining system suggests less concern. However, all systems indicate species lacking assessment. Human activities and exotic alien species are present on 60% of 131 islands. The taxonomic turnover value is high (0.89), with a clear herpetofaunal differentiation between the two biogeographic regions. The species–area and species–mainland distance relationships are positive. Insular herpetofauna faces a high percentage of threats, with the Neotropical provinces more heavily impacted. It is urgent to explore the remaining islands (3,079 islands) and better incorporate insular populations and species in ecological, evolutionary, and systematic studies. In the face of the biodiversity crisis, islands will play a leading role as a model to apply restoration and conservation strategies.  相似文献   

10.
Approximately 20% of North American minnows are considered imperiled. The factors responsible for imperilment in this group are complex, but the relationship of spawning mode to conservation of North American minnows has not been explored. I provide a summary of the spawning modes of imperiled North American minnows, discuss patterns between these modes and conservation status, and predict the spawning modes for several poorly-known imperiled species. Of the 46 species of North American minnows that are imperiled, spawning modes are known for only 13 species. All spawning modes are represented in the imperiled group of minnows except mound-building and egg-clustering, and with the exception of crevice-spawners and pit-ridge-builders, the percentage of imperiled minnows in each category of spawning mode is roughly proportional to the percentage of minnows in that category overall. Species with complex spawning modes, such as mound-building, pit-building and egg-clustering, are among the most common fishes in North American streams. This pattern suggests that there is a relationship between parental care and success (lack of imperilment) in minnows. Spawning mode is an important consideration in the formulation of recovery plans and proactive conservation efforts.  相似文献   

11.
Threatened species lists continue to grow while the world’s governments fail to meet biodiversity conservation goals. Clearly, we are failing in our attempts to conserve biodiversity. Yet 37 mammal species genuinely improved in status in the 2009 IUCN Red List, suggesting there are ways to successfully conserve biodiversity. Here, I compare the threats and conservation actions (proposed and implemented) by the expert assessors of the Red List of improving species to a further 144 declining mammal species to determine whether specific threats were more easily remedied, and whether certain conservation actions were more successful than others. Declining species were faced with different threatening processes to mammals improving in status suggesting some threats were easier to treat (e.g. hunting) than others (climate change, invasive species). Declining species had different proposed and implemented conservation actions than improving species suggesting some actions are more successful than others. Threatened species were invariably found in conservation areas, suggesting protected area creation alone is not an overly successful strategy for species at risk of extinction. Conservation actions were more frequently implemented for improving than declining species suggesting active conservation is effective in improving the status of biodiversity. There were significant differences between proposed and implemented conservation actions suggesting some actions are easier to implement than others. Reintroduction, captive breeding and hunting restriction were more effective in conserving mammals than site creation and invasive species control. These findings highlight effective conservation actions for mammals worldwide and allow the rationalisation of threat mitigation measures to ensure economically justifiable biodiversity conservation strategies.  相似文献   

12.
Heard M  Smith KF  Ripp K 《PloS one》2011,6(8):e23150
Extinction risks are increasing for amphibians due to rising threats and minimal conservation efforts. Nearly one quarter of all threatened/extinct amphibians in the IUCN Red List is purportedly at risk from the disease chytridiomycosis. However, a closer look at the data reveals that Batrachochytrium dendrobatidis (the causal agent) has been identified and confirmed to cause clinical disease in only 14% of these species. Primary literature surveys confirm these findings; ruling out major discrepancies between Red List assessments and real-time science. Despite widespread interest in chytridiomycosis, little progress has been made between assessment years to acquire evidence for the role of chytridiomycosis in species-specific amphibian declines. Instead, assessment teams invoke the precautionary principle when listing chytridiomycosis as a threat. Precaution is valuable when dealing with the world's most threatened taxa, however scientific research is needed to distinguish between real and predicted threats in order to better prioritize conservation efforts. Fast paced, cost effective, in situ research to confirm or rule out chytridiomycosis in species currently hypothesized to be threatened by the disease would be a step in the right direction. Ultimately, determining the manner in which amphibian conservation resources are utilized is a conversation for the greater conservation community that we hope to stimulate here.  相似文献   

13.
黑叶猴是栖息于喀斯特石山地区的珍稀濒危灵长类动物,由于非法捕杀和栖息地丧失,种群数量急剧减少。2017年10-12月,我们采用样方法调查恩城国家级自然保护区及其周边地区黑叶猴的种群分布、数量及保护现状,分析其致危因素,为制定有效管理行动计划提供理论依据。本次调查共记录到黑叶猴夜宿地89处,其中有43处夜宿地下方有新鲜排泄物。结合本次调查和访问,确定黑叶猴的种群数量为18群100~105只,包括1只全白化黑叶猴成年雌性个体;其中11群分布在保护区内,7群分布在保护区外。猴群由3~12只个体组成。栖息地破碎化和退化是威胁恩城保护区黑叶猴种群生存的主要因素。  相似文献   

14.
We review interactions between extrinsic threats to marine fishes and intrinsic aspects of their biology that determine how populations and species respond to those threats. Information is available on the status of less than 5% of the world's approximately 15500 marine fish species, most of which are of commercial importance. By 2001, based on data from 98 North Atlantic and northeast Pacific populations, marine fishes had declined by a median 65% in breeding biomass from known historic levels; 28 populations had declined by more than 80%. Most of these declines would be sufficient to warrant a status of threatened with extinction under international threat criteria. However, this interpretation is highly controversial, in part because of a perception that marine fishes have a suite of life history characteristics, including high fecundity and large geographical ranges, which might confer greater resilience than that shown by terrestrial vertebrates. We review 15 comparative analyses that have tested for these and other life history correlates of vulnerability in marine fishes. The empirical evidence suggests that large body size and late maturity are the best predictors of vulnerability to fishing, regardless of whether differences among taxa in fishing mortality are controlled; there is no evidence that high fecundity confers increased resilience. The evidence reviewed here is of direct relevance to the diverse criteria used at global and national levels by various bodies to assess threat status of fishes. Simple life history traits can be incorporated directly into quantitative assessment criteria, or used to modify the conclusions of quantitative assessments, or used as preliminary screening criteria for assessment of the approximately 95% of marine fish species whose status has yet to be evaluated either by conservationists or fisheries scientists.  相似文献   

15.
Australia is in the midst of an extinction crisis, having already lost 10% of terrestrial mammal fauna since European settlement and with hundreds of other species at high risk of extinction. The decline of the nation''s biota is a result of an array of threatening processes; however, a comprehensive taxon‐specific understanding of threats and their relative impacts remains undocumented nationally. Using expert consultation, we compile the first complete, validated, and consistent taxon‐specific threat and impact dataset for all nationally listed threatened taxa in Australia. We confined our analysis to 1,795 terrestrial and aquatic taxa listed as threatened (Vulnerable, Endangered, or Critically Endangered) under Australian Commonwealth law. We engaged taxonomic experts to generate taxon‐specific threat and threat impact information to consistently apply the IUCN Threat Classification Scheme and Threat Impact Scoring System, as well as eight broad‐level threats and 51 subcategory threats, for all 1,795 threatened terrestrial and aquatic threatened taxa. This compilation produced 4,877 unique taxon–threat–impact combinations with the most frequently listed threats being Habitat loss, fragmentation, and degradation (n = 1,210 taxa), and Invasive species and disease (n = 966 taxa). Yet when only high‐impact threats or medium‐impact threats are considered, Invasive species and disease become the most prevalent threats. This dataset provides critical information for conservation action planning, national legislation and policy, and prioritizing investments in threatened species management and recovery.  相似文献   

16.
Rates of biodiversity loss are higher in freshwater ecosystems than in most terrestrial or marine ecosystems, making freshwater conservation a priority. However, prioritization methods are impeded by insufficient knowledge on the distribution and conservation status of freshwater taxa, particularly invertebrates. We evaluated the extinction risk of the world''s 590 freshwater crayfish species using the IUCN Categories and Criteria and found 32% of all species are threatened with extinction. The level of extinction risk differed between families, with proportionally more threatened species in the Parastacidae and Astacidae than in the Cambaridae. Four described species were Extinct and 21% were assessed as Data Deficient. There was geographical variation in the dominant threats affecting the main centres of crayfish diversity. The majority of threatened US and Mexican species face threats associated with urban development, pollution, damming and water management. Conversely, the majority of Australian threatened species are affected by climate change, harvesting, agriculture and invasive species. Only a small proportion of crayfish are found within the boundaries of protected areas, suggesting that alternative means of long-term protection will be required. Our study highlights many of the significant challenges yet to come for freshwater biodiversity unless conservation planning shifts from a reactive to proactive approach.  相似文献   

17.
A joint analysis considering the world-wide distribution and threat status of Central European vascular plants was carried out to derive conservation priorities for threatened species. A list of 417 taxa is presented, which are threatened throughout Central Europe and/or show a predominantly Central European distribution. As a first step, all plants mentioned in Central European national Red Lists were included in a synoptic table, resulting in a total of 3255 taxa threatened or rare in at least one country. To select species with a high conservation priority, two parameters were estimated: threat status for Central Europe and a new category termed responsibility for the conservation of a species. As criteria for this second parameter, we used the proportion of Central Europe on the world range of a species, the position of Central Europe within this range, and its world-wide threat status. A simple category system including four responsibility categories is proposed. For all species selected, threat status and a responsibility assessment for the whole of Central Europe is given, as well as position and proportion of Central Europe on their world range. By comparison of threat status and responsibility, this list provides a background for assessing national conservation priorities as well as for making decisions about inclusion in international conventions on species conservation. This was shown by a comparison of the species selected using this approach with those included in the two most important European instruments for species conservation – the Berne Convention and the Habitats Directive.  相似文献   

18.
Zoos have played a pivotal role in the successful reinforcement and reintroduction of species threatened with extinction, but prioritization is required in the face of increasing need and limited capacity. One means of prioritizing between species of equal threat status when establishing new breeding programs is the consideration of evolutionary distinctness (ED). More distinct species have fewer close relatives such that their extinction would result in a greater overall loss to the Tree of Life. Considering global ex situ holdings of birds (a group with a complete and well‐detailed evolutionary tree), we investigate the representation of at‐risk and highly evolutionarily distinct species in global zoo holdings. We identified a total of 2,236 bird species indicated by the Zoological Information Management System as being held in zoological institutions worldwide. As previously reported, imperiled species (defined as those possessing endangered or critically endangered threat status) in this database are less likely to be held in zoos than non‐imperiled species. However, we find that species possessing ED scores within the top 10% of all bird species are more likely to be held in zoos than other species, possibly because they possess unique characteristics that have historically made them popular exhibits. To assist with the selection of high priority ED species for future zoo conservation programs, we provide a list of imperiled species currently not held in zoos, ranked by ED. This list highlights species representing particular priorities for ex situ conservation planners, and represents a practical tool for improving the conservation value of zoological collections.  相似文献   

19.
Islands are generally reported to have much higher extinction rates and levels of threat than continental areas. This perception is based largely on studies of vertebrates. A recent assessment of the biodiversity of the Seychelles islands enables the status of a range of taxonomic groups to be compared. A high proportion of the fauna is found to be threatened, with Dictyoptera being the most threatened insect order (51% of 34 native species) followed by Orthoptera (47% of 68 species). Lower levels of threat are found in Diptera (28% of 562 species), Dermaptera (24% of 21 species) and Lepidoptera (21% of 517 species). Differences between the orders relate mainly to distribution patterns, with the most threatened orders having the highest proportions of endemic and restricted range species. The main threats for most orders are habitat deterioration due to invasion by introduced plant species, sea level rise and climate change. These threat factors are different from those reported to affect vertebrates, which are generally considered to be threatened by introduced predators resulting in critically low population sizes. These findings indicate that conservation sources would be more useful and cost effective for insect conservation if directed to habitat maintenance and restoration rather than to alien predator control.  相似文献   

20.
Some species face greater anthropogenic threats than others, and have increased need for scarce conservation resources. Yet how resources are allocated for conservation remains little known. I examined the distribution of research effort, an index of resource allocation, across Felidae (the cat family), a diverse, widely-distributed, and threatened taxon. I performed complete searches of the published literature for all cat species from 1986 to 2007, collecting a total of 2,462 papers, of which 926 represented in situ studies. Threat status, as ranked by a World Conservation Union report in 1996, was significantly correlated with geographical range size, with narrowly distributed species tending to be more at risk. Unlike in many other taxa, threat status was not correlated with body size. The number of total and in situ publications (“research effort”) per species was significantly and positively related to body size, but not to threat status or geographical range size. Research effort, rather than being distributed according to actual threat status, is highly skewed towards large species. However, the ratio of the number of studies on the 10 smallest cat species to the number on the 10 largest species has increased significantly since 1986. Yet many species remain severely understudied; I identify 14 cat species that are threatened and have <10 in situ publications each. These species critically require a greater share of the conservation research effort.  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