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1.
Although large-scale biodiversity declines are ongoing, certain conservation actions have made a positive difference. Rates of extinction and endangerment of vertebrate species, for instance, have probably been reduced via conservation interventions. Such conservation actions operate at different spatial scales. Habitat preservation and endangered species recovery are examples of conservation successes at microscales. Mesoscale conservation includes regional cooperation among neighboring countries that has arrested population declines of endangered species, such as mountain gorillas. At macroscales, public pressure on multinational corporations has sometimes resulted in their abandoning environmentally damaging practices or suppliers with poor environmental records. Overall, conservation projects such as these need more long-term funding and greater political and popular support, and must also include provisions to evaluate and document their outcomes. As we discuss here, a focus on conservation successes achieved at different scales can help to promote these aims and guide future conservation victories.  相似文献   

2.
The current freshwater fish fauna crisis is such that natural resource managers urgently need to identify priorities and understand the management consequences of actions aimed at maximizing the preservation of biodiversity. Freshwater research is often poorly linked to conservation ecology; and interdisciplinary studies illustrating examples of freshwater ecosystem conservation are scarce. The Iberian Peninsula has a long history of anthropogenic disturbance that has led to the poor conservation status of its ichthyofauna, with 52 % of species now catalogued as critically endangered, endangered or vulnerable, according to UICN criteria. This paper gives an overview of the main threats (habitat degradation, hydrological alterations and exotic species) that have altered the function and connectivity of Iberian rivers. Case-study examples are provided to analyse the repercussions of these threats and the management actions planned or already performed in these systems. The interaction of many threats is responsible for native fish decline. However, freshwater managers and researchers should not let the trees prevent them from seeing the overall wood, when seeking to achieve practical solutions with the best balanced cost benefit and the collaboration of all ecosystem researchers and stakeholders. Conservation efforts should be focused on the preservation of ecological processes, in order to achieve the goals of the Water Framework Directive and guarantee the conservation of Iberian native fish species.  相似文献   

3.
Genetic variation is believed to be a prerequisite for the short-and long-term survival of the plant species in their natural habitat. It depends on many environmental factors which determine the number of alleles on various loci in the genome. Therefore, it is important to understand the genetic composition and structure of the rare and endangered plant species from their natural habitat to develop successful management strategies for their conservation. However, rare and endangered plant species have low genetic diversity due to which their survival rate is decreasing in the wilds. The evaluation of genetic diversity of such species is very important for their conservation and gene manipulation. However, plant species can be conserved by in situ and in vitro methods and each has advantages and disadvantages. DNA banking can be considered as a means of complimentary method for the conservation of plant species by preserving their genomic DNA at low temperatures. Such approach of preservation of biological information provides opportunity for researchers to search novel genes and its products. Therefore, in this review we are describing some potential biotechnological approaches for the conservation and further manipulation of these rare and endangered plant species to enhance their yield and quality traits.  相似文献   

4.
During recent decades, over 40% of Japanese estuarine tidal flats have been lost due to coastal developments. Local populations of the saltmarsh sesarmid crab Clistocoeloma sinense, designated as an endangered species due to the limited suitable saltmarsh habitat available, have decreased accordingly, being now represented as small remnant populations. Several such populations in Tokyo Bay, have been recognised as representing distributional limits of the species. To clarify the genetic diversity and connectivity among local coastal populations of Japanese Clistocoeloma sinense, including those in Tokyo Bay, mitochondrial DNA analyses were conducted in the hope of providing fundamental information for future conservation studies and an understanding of metapopulation dynamics through larval dispersal among local populations. All of the populations sampled indicated low levels of genetic diversity, which may have resulted from recent population bottlenecks or founder events. However, the results also revealed clear genetic differentiation between two enclosed-water populations in Tokyo Bay and Ise-Mikawa Bay, suggesting the existence of a barrier to larval transport between these two water bodies. Since the maintenance of genetic connectivity is a requirement of local population stability, the preservation of extant habitats and restoration of saltmarshes along the coast of Japan may be the most effective measures for conservation of this endangered species.  相似文献   

5.
云南是毒药树(Sladenia celastrifolia)的分布中心,日益严重的人为干扰不可避免地影响毒药树种群的数量特征。基于毒药树年龄与胸径之间的关系,初步分析了受人为干扰程度不同的两个种群的年龄结构、静态生命表和存活曲线,并对这两个种群进行了比较。严重受干扰的种群的幼苗库相对不足,Ⅰ龄级个体数比例为12.7%,Ⅱ、Ⅲ、Ⅳ龄级个体数所占比例为80.3%,种群衰退趋势明显;未受干扰的种群幼苗库相对充足,年龄结构呈现稳定种群的特征。这两个种群的生命表也存在差异,其中最明显的就是严重受干扰的种群的Ⅰ龄级和Ⅱ龄级的死亡率为负,这是幼苗库不足的一个直接反映。两个种群的存活曲线都表现出低龄级个体死亡率高的特征,但未受干扰的种群各龄级个体的死亡率的变化幅度较小。毒药树种群的各项特征与鹅掌楸(Liriodendron chinense)及其它几种濒危植物的相关特征相似。虽然毒药树还未被列为受威胁的物种,但它已具备IUCN所定义的受威胁物种的特点,因此,对它的保护已十分必要,除了在野外建立相应的毒药树保护点之外,在植物园中培植人工种群也是必须的。  相似文献   

6.
红豆树(Ormosia hosiei)为中国特有种,兼具材用、药用、园艺观赏及科学研究等价值,但是日益严重的干扰对红豆树种群造成了极大影响。本文基于红豆树胸径与年龄之间的关系,初步分析了受干扰程度不同的3个红豆树种群的年龄结构、种群静态生命表、存活曲线及死亡率和消失率曲线。结果显示:受严重干扰的种群幼苗严重不足,种群表现出明显的衰退趋势;近年来受中度干扰的种群幼苗个体数占绝对优势,为各级数量的7877%;长期受轻微干扰的种群年龄级结构表现出为稳定的特征。这3个种群生命表最大的差异在于受干扰最严重种群的第Ⅰ龄级和第Ⅱ龄级的死亡率为负,这说明其幼苗库不足。存活曲线都存在波动,长期受轻微干扰的种群死亡率变幅最小。研究认为,红豆树种质资源和分布面积都有所减少,应加强科学研究和保护,进行适度干扰,使种群朝着进展演替的方向发展。  相似文献   

7.
For conservation managers tasked with recovering threatened species, genetic structure can exacerbate the rate of loss of genetic diversity because alleles unique to a sub-population are more likely to be lost by the effects of random genetic drift than if a population is panmictic. Given that intensive management techniques commonly used to recover threatened species frequently involve movement of individuals within and between populations, managers need to be aware not only of pre-existing levels of genetic structure but also of the potential effects that intensive management might have on these patterns. The Mauritius parakeet (Psittacula echo) has been the subject of an intensive conservation programme, involving translocation and reintroduction that has recovered the population from less than 20 individuals in 1987 to approximately 500 in 2010. Analysis of genotype data derived from 18 microsatellite markers developed for this species reveals a clear signal of structure in the population before intensive management began, but which subsequently disappears following management intervention. This study illustrates the impacts that conservation management can have on the genetic structure of an island endemic population and demonstrates how translocations or reintroductions can benefit populations of endangered species by reducing the risk of loss of genetic diversity.  相似文献   

8.
This review considers interactive management of wild and zoo populations as a stratesy to support habitat preservation, help sustain key endangered species, and hasten the evolution of zoos and aquaria as proactive conservation organizations. Interactive management supports key species' subpopulations in an integrated fashion, using their study in nature as a way to understand wildlife habitats, ecological processes and conservation threats. In the face of human increase and habitat destruction, the survival of much wildlife will depend upon the utility of fragments of habitat and the survival of relatively small populations whose habitats are reduced or altered and whose numbers are capped. Under such conditions, interactive wild-captive metapopulation strategies may increase the security of key species.  相似文献   

9.
The World Conservation Union (1987) defines a translocation as a release of animals with the intention of establishing, reestablishing, or augmenting an existing population. Despite frequent use as a tool for the management of threatened and endangered wildlife, the full benefits of translocations often go unrealized. In this article, I demonstrate how translocations can achieve outputs for conservation management, conservation science, and the wider human community, using North Island (NI) Saddleback or Tieke ( Philesturnus rufusater ) as an illustrative example. From a conservation management perspective, NI Saddleback have been salvaged from a relic population of less than 500 birds on 484-ha Hen Island to a metapopulation of approximately 6,000 birds on 13 offshore islands and at two mainland New Zealand sites. These translocations have reduced the risk of global extinction for this species and helped restore the ecosystems involved. All these translocations have occurred in the past 42 years from known source populations and with known numbers of birds released. The resulting replicated serial population bottlenecks provide numerous scientific opportunities for conservation and biological research. Although the first Saddleback translocations were to reserves closed to the public, subsequent translocations have been to open reserves, providing the wider human community with an opportunity to see and be actively involved in the management of a threatened endemic species. This has raised the profile of both NI Saddleback and other species and has provided wider community conservation benefits. These three outputs illustrate the value of translocations for resource management and conservation science and for increasing community interest, participation, and investment in biological conservation.  相似文献   

10.
种群生存力分析:准确性和保护应用   总被引:12,自引:0,他引:12  
李义明 《生物多样性》2003,11(4):340-350
目前已提出了五类估计濒危物种绝灭风险的种群生存力分析模型 ,即 :分析模型、单种群确定性模型、单种群随机模型、异质种群模型和显空间模型。模型的选择取决于物种的生活史特征和可用的数据。与用于保护实践的其他方法相比 ,种群生存力分析 (PVA)是相对准确的量化工具。然而 ,一些濒危物种种群统计学数据质量差和种群动态的有关假说模糊不清可能影响到模型预测的准确性 ,因此 ,要谨慎地使用PVA。在西方国家 ,PVA在濒危物种保护计划和管理中应用越来越广泛。它主要用于 :( 1)预测濒危物种未来的种群大小 ;( 2 )估计一定时间内物种的绝灭风险 ;( 3 )评估一套保护措施 ,确定哪个能使种群的存活时间最长 ;( 4)探索不同假说对小种群动态的影响 ;( 5 )指导濒危动物野外数据的搜集工作。我国的濒危物种很多 ,然而开展PVA研究的濒危物种却很少。应大力发展适合于模拟我国特有濒危物种及其保护问题的PVA模型  相似文献   

11.
Species are the most commonly recognised unit for conservation management, yet significant variation can exist below the level of taxonomic recognition and there is a lack of consensus around how a species might be defined. This definition has particular relevance when species designations are used to apportion conservation effort and when definitions might be made through legislation. Here, we use microsatellite DNA analyses to test the proposition that the last remaining populations of the endangered grassland earless dragon (Tympanocryptis pinguicolla) harbour substantial cryptic genetic variation. Our study provides strong evidence that long historical isolation and the recent impacts of urbanization, have led to genetic differentiation in microsatellite DNA allele frequencies and high numbers of private alleles among three genetic clusters. This differentiation is partially concordant with previous mitochondrial DNA analyses, which show the two regions (Canberra and Monaro) where this species exists, to be reciprocally monophyletic, but differs through the identification of a third genetic cluster that splits a northern Canberra cluster from that of southern Canberra. Our data also identify a stark contrast in population genetic structure between clusters such that high levels of genetic structure are evident in the highly urbanised Canberra region but not in the largely rural Monaro region. We conclude that this species, like many reptiles, harbours considerable cryptic variation and currently comprises three distinct and discrete units. These units could be classified as separate species for the purpose of conservation under the relevant Australian and international Acts drawing management appropriate to that status.  相似文献   

12.
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   

13.
Edge and central populations can show great differences regarding their genetic variation and thereby also in their probability of extinction. This fact might be of great importance for the conservation strategies of endangered species. In this study we examine the level of microsatellite variability within three threatened edge populations of the green lizard subspecies Lacerta viridis viridis (Laur.) in Brandenburg (Germany) and compare the observed variation to other edge and central populations within the northern species range. We demonstrate that the northernmost edge populations contain less genetic variation in comparison to the central population. However, there were no observable significant differences to the other edge population included in this study. Surprisingly, we observed a high genetic differentiation in a small geographical range between the three endangered populations in Brandenburg, which can be explained by processes like fragmentation, isolation, genetic drift and small individual numbers within these populations. We also detected unique genetic variants (alleles), which only occurred in these populations, despite a low overall genetic variation. This study demonstrates the potential of fast evolving markers assessing the genetic status of endangered populations with a high resolution. It also illustrates the need for a comparative analysis of different regions within the species range, achieving a more exact interpretation of the genetic variation in endangered populations. This will aid future management decisions in the conservation of genetic diversity in threatened species.  相似文献   

14.
Long-term monitoring programs are necessary to assess populations for conservation planning and management decisions. Hibernating bats in North America have declined because of numerous natural and human-induced disturbances. White-nose syndrome (WNS) has become the most serious threat to North American cave-dwelling bats, leading to significant population declines in several species. We examined trends in hibernating bat populations at 11 hibernacula in northern Georgia and Alabama, USA, from 2013–2022, beginning when WNS was first detected in the region. Although we observed interannual variation in numbers of the federally endangered gray bat (Myotis grisescens), mean counts remained stable over time. In contrast, the tricolored bat (Perimyotis subflavus) and the federally endangered northern long-eared bat (M. septentrionalis) declined by >90% in the first 5 years after WNS detection in the region. Although no northern long-eared bats have been reported since 2019, tricolored bat counts stabilized following initial declines. Understanding changes in bat populations as WNS continues to spread, and determining the extent of population declines, is necessary for making appropriate management decisions. Our findings elucidate the status of cave-dwelling bat species along the periphery of the white-nose syndrome endemic region and highlight the importance of monitoring bat communities on a regional scale to develop effective conservation strategies.  相似文献   

15.
Effective habitat management is predicted to have positive effects on populations and species of conservation concern. Although studies have shown that ecological processes such as colonization can be promoted after habitat management, we still need more information on the survival and reproductive consequences at the individual level in order to reach positive conservation outcome. Here we assess the effects of reproductive habitat supplementation (host oviposition plant) on survival and mating success of an endangered endemic damselfly, Calopteryx exul, using capture-mark-recapture data. We first determined that the species prefer to oviposit on floating leaves of Potamogeton spp. Based on Cormack-Jolly-Seber modeling, we found that recapture and survival probabilities were positively affected by the number of the host oviposition patches of the host plant. Moreover, we showed a strong positive relationship between adult lifespan and lifetime mating success. Our results suggest that host-plant provisioning for reproduction not only increases the survival of individuals, but also increases the number of matings per lifetime. The procedure of supplying reproductive sites may enhance population growth of threatened odonates and other aquatic insects.  相似文献   

16.
The endangered Shivwits milkvetch, Astragalus ampullarioides, is a perennial, herbaceous plant. This Utah endemic was federally listed as endangered in 2001 because of its high habitat specificity and low numbers of individuals and populations. All habitat currently occupied by A. ampullarioides was designated as critical by the U.S. Fish and Wildlife Service in 2006 as a result of conservation litigation. We used AFLP markers to assess genetic differentiation among the seven extant populations and quantified genetic diversity in each. Six different AFLP markers resulted in 217 unambiguous polymorphic loci. We used multiple methods to examine any changes in population genetic structure in this species over time. Results indicate that A. ampullarioides had much higher gene flow among populations in the past, but has since fragmented into regional genetic units. These regions further fragmented genetically, and extant populations have differentiated through genetic drift. Populations had low levels of gene flow, even between geographically close populations. Rapid urban development reduces gene flow among regions and encroaches on populations of A. ampullarioides and remaining patches of unoccupied habitat. The genetic makeup of each of the extant populations should be carefully considered in management decisions such as population establishment or augmentation.  相似文献   

17.
《中国濒危动物红皮书》依据我国动物所面临的濒危,对我国濒危动物的濒危等级划分,种群现状,致危因素和保护措施等进行了描述说明,首批收录了535种濒危动物。本文以《中国濒危动物红皮书》中所收录的352种濒危脊椎动物(不含鸟类(以下简记为“濒危植物”)为研究对象,整理统计了现有濒危物种的分布资料,在GIS支持下,对中国濒危动物的地理分布进行了研究。结果表明,中国濒危动物物种呈明显的集聚分布,最密集的地区是横断山区,海南岛,西双版纳和云贵高原;而在华北平原,内蒙古东部,黄土高原和东北平原等地区出现大片空白区。影响濒危动物分布的主要因素有热量和水分条件,地形条件等自然条件以及历史开发,人为破坏等人文条件。山地因地形屏障作用而保留了较多的古老物种,其较为复杂的环境因子也有益物种的生存,因而物种丰富度较高。大多数动物对于水分和热量的依赖性较强,因此水热条件对其分布的限制作用十分明显。人为破坏较为严重的地区,濒危物种稀少;污染,开荒等引起的环境问题对于现存动物的威胁很。运用Dobson排除算法得到云南勐腊县等9个县分布有168种濒危动物,占全国总数(海生种类及仅分布于台湾和香港的特有种除外)的51.5%,而其土地面积之和仅为全国陆地总面积的0.9%。而云南勐腊县等94个县市就分布有中国所有的濒危动物。这些地区是我国生物多样性保护应该优先考虑的地方。  相似文献   

18.
Tremendous strides have been made in recent years to broaden our understanding of reproductive processes in nondomestic felid species and further our capacity to use this basic knowledge to control and manipulate reproduction of endangered cats. Much of that progress has culminated from detailed scientific studies conducted in nontraditional laboratory settings, frequently at collaborating zoological parks but also under more primitive conditions, including in the field. A mobile laboratory approach is described, which incorporates a diverse array of disciplines and research techniques. This approach has been extremely useful, especially for conducting gamete characterization and function studies as well as reproductive surveys, and for facilitating the development of assisted reproductive technology. With continuing advances in assisted reproduction in rare felids, more procedures are being conducted primarily as service-related activities, targeted to increase effectiveness of species propagation and population management. It can be a challenge for both investigators and institutional animal care and use committees (IACUCs) to differentiate these service-based procedures from traditional research studies (that require IACUC oversight). For research with rare cat species, multi-institutional collaboration frequently is necessary to gain access to scientifically meaningful numbers of study subjects. Similarly, for service-based efforts, the ability to perform reproductive procedures across institutions under nonstandard laboratory conditions is critical to applying reproductive sciences for managing and preserving threatened cat populations. Reproductive sciences can most effectively assist population management programs (e.g., Species Survival Plans) in addressing conservation priorities if these research and service-related procedures can be conducted "on the road" at distant national and international locales. This mobile laboratory approach has applications beyond endangered species research, notably for other scientific fields (e.g., studies of hereditary disease in domestic cat models) in which bringing the laboratory to the subject is of value.  相似文献   

19.
Hawai''I''s coastal plain wetlands are inhabited by five endangered endemic waterbird species. These include the Hawaiian Coot (''alae ke''oke''o), Hawaiian Duck (koloa maoli), Hawaiian Stilt (ae''o), Hawaiian Gallinule (Moorhen) (''alae ''ula), and Hawaiian Goose (nēnē). All five species are categorized as being “conservation reliant.” The current strategy to recover these endangered birds includes land protection and active management of wetlands. To assess the effectiveness of the current management paradigm, we compared species population trends across the state to those on six actively managed wetland national wildlife refuges (Refuges) thought to be critical for the survival of these endangered species. To perform the evaluation we relied on systematic semiannual population counts that have been conducted across most wetlands in the state and monthly population counts that have occurred on Refuges during the same time period. We found that statewide and Refuge populations of the Hawaiian Coot, Stilt and Gallinule have rebounded from historic lows and over the last 20 years have slowly increased or remained stable. We also documented that Refuges are important to each species year-round and that a disproportionately larger percentage of the population for each species is found on them. Understanding of why Refuges successfully house a disproportionate percentage of these “conservation reliant” species can inform current and future conservation efforts as well as ensure long-term population viability for these species.  相似文献   

20.
Multi-decadal datasets for endangered species that track both populations and performance of management interventions are rare. One such dataset is for the critically endangered Spotted handfish, a species which has been used as a conservation model for the most endangered of the marine bony fish families the Brachionichthyidae. We assessed a 23-year, multi-site, time-series of population density surveys for the spotted handfish as well as a conservation intervention, the planting of ∼ 14,000 artificial spawning habitats (ASH). Data ownership spanned multiple Principal Investigators (PIs) and key data and covariates, such as monitoring and interventions, were often documented within personal files and difficult to access grey literature. We consolidated and curated these data, identifying gaps in the time-series and their causes and isolating confounding factors before we assessed population trends and the effectiveness of ASH planting. Both funding gaps and the 2020 Covid-19 lockdown produced breaks in the time-series. Breeding season observations mostly occurred in the early part of the dataset and there was also a change in method that needed to be considered when interpretating the time-series. There was an overall decline in fish observed between 1997 and 2019 but, at least since 2014, there has been stabilisation of the population. Local populations of spotted handfish can either be highly dynamic or relatively stable but population increases were linked to the long-running, conservation intervention of planting ASH. As local populations can be dynamic, the functional life span of the ASH is limited and threats to the species - chronic, stochastic and climate - are ongoing, spotted handfish may be a ‘conservation reliant’ species that require annual site-specific monitoring, insitu interventions and existu captive husbandry.  相似文献   

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