982 resultados para wildlife conservation


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Ancherythroculter nigrocauda is a cyprinid fish endemic to the upper reaches of the Yangtze River, which has been reported to have 2 or 3 chambers to its air bladder. Morphological studies showed no differences between individuals with different types of air bladder, but did demonstrate geographical differences from different sources. After the completion of the Three Gorges Dam, it was expected that the population of this species would decrease, but artificial breeding and stocking is under consideration to protect this species from extinction. In the present study, mtDNA cytochrome b gene sequences were determined and analyzed for A. nigrocauda samples of different morphotypes and sources to identify their genetic differentiations, and thereby guide plans for the artificial propagation and conservation of this species. Haplotype diversity index values (h) and nucleotide diversity values (pi) for all the populations were found to be high indicating their high level genetic diversity. An analysis of molecular variance identified no differentiation among the studied populations. Therefore, we suggested that the individuals of different morphological types and geographical sources belong to the same species. To maintain its high level genetic diversity, it mill he necessary to use large and diverse sources of parental fish for artificial reproduction.

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The Yangtze finless porpoise, Neophocaena phocaenoides asiaeorientalis, is all endangered small cetacean that occurs only in the middle and lower reaches of the Yangtze River of China. The establishment of a breeding population of the porpoise in Tian-e-Zhou Baiji National Natural Reserve represents the first attempt at ex situ conservation efforts for a cetacean species. With the goal of effective protection, management, and monitoring of this preserved population, we examined its genetic diversity using 930 bp of mtDNA control region sequences and 13 polymorphic microsatellite loci. A very low level of genetic variation (h = 0.6010 +/- 0.0029 s.d.; pi = 0.0007 +/- 0.0000002 s.d.) in the mtDNA control region sequences and a moderate genetic diversity (Ho = 0.5740 +/- 0.2575 s.d.) in the microsatellites were detected in the population. It is necessary to introduce more individuals with representative genetic variations into the reserve ill order to foml a larger and healthier group structure for long-term survival of the population. Successful establishment of the Yangtze finless porpoise population in the Reserve also provides a useful model for an ex situ conservation programme for other rare and endangered species. (c) 2005 International Council for the Exploration ofthe Sea. Published by Elsevier Ltd. All rights reserved.

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Background. As the sole freshwater subspecies of finless porpoise (Neophocaena phocaenoides), the Yangtze finless porpoise (N. p. asiaeorientalis) lives only in the middle and lower reaches of the Yangtze River and its appended Poyang and Dongting Lakes. As a result of human activity on the river, including over and illegal fishing, pollution, transportation and dam construction, the population of Yangtze finless porpoises has been steadily and rapidly decreasing during the past several decades, which leads the animal to be endangered. Methods. For saving this unique animal from extinction, three corresponding measures, in situ conservation, ex situ conservation, and intensifying breeding research in captivity, were proposed and have been implemented since the 1980s. Results. After successfully rearing the animals in captivity for almost nine years, the first Yangtze finless porpoise was successfully born in captivity on July 5, 2005. The calf is male, with a body length of 69 cm. This is the first freshwater cetacean ever born in captivity. Conclusion. The successful birth of this calf confirms that it is possible to breed the Yangtze finless porpoise in captivity. Furthermore, this will greatly benefit the conservation efforts, and also greatly bolster our on-going efforts to study the reproductive biology of these animals. Recommendation. More studies and efforts are expected to establish a sustainable, captive colony of the Yangtze finless porpoise, which will not only greatly expand our knowledge about the reproduction biology of this animal, but also help to redeem the wild population through a careful yearly 'soft releasing' process.

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Understanding the population genetic structure is a prerequisite for conservation of a species. The degree of genetic variability characteristic of the mitochondrial DNA control region has been widely exploited in studies of population genetic structure and can be useful in identifying meaningful population subdivisions. To estimate the genetic profile of the Yangtze finless porpoise (Neophocaena phocaenoides asiaeorientalis), an endangered freshwater population endemic to China, the complete mtDNA control region was examined in 39 individuals belonging to seven different stocks inhabiting the middle and lower reaches of the Yangtze River. Very low genetic diversity was found (nucleotide diversity 0.0011 +/- 0.0002 and haplotypic diversity 0.65 +/- 0.05). The mtDNA genetic pattern of the Yangtze population appears to indicate a founder event in its evolutionary history and to support the marine origin for this population. Analyses by F-st and Phi(st) yielded statistically significant population genetic structure (F-st = 0.44, P < 0.05; phi(st) = 0.36, P < 0.05). These results may have significant implications for the management and conservation of the Yangtze finless porpoise in the future.

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The largest damming project to date, the Three Gorges Dam has been built along the Yangtze River (China), the most species-rich river in the Palearctic region. Among 162 species of fish inhabiting the main channel of the upper Yangtze, 44 are endemic and are therefore under serious threat of global extinction from the dam. Accordingly, it is urgently necessary to develop strategies to minimize the impacts of the drastic environmental changes associated with the dam. We sought to identify potential reserves for the endemic species among the 17 tributaries in the upper Yangtze, based on presence/absence data for the 44 endemic species. Potential reserves for the endemic species were identified by characterizing the distribution patterns of endemic species with an adaptive learning algorithm called a "self-organizing map" (SOM). Using this method, we also predicted occurrence probabilities of species in potential reserves based on the distribution patterns of communities. Considering both SOM model results and actual knowledge of the biology of the considered species, our results suggested that 24 species may survive in the tributaries, 14 have an uncertain future, and 6 have a high probability of becoming extinct after dam filling.

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1. Baiji were sighted 17 times during three recent simultaneous multi-vessel surveys in the Yangtze River, China (November 4-10, 1997; December 4-9, 1998; October 31-November 5, 1999). There were 11 sightings in 1997 (consisting of 17 animals), five in 1998 (seven animals), and two in 1999 (four animals). It was concluded that 13 individuals Could be considered as a minimum number of the baiji currently in the Yangtze River. 2. An annual rate of population decrease was roughly estimated as 10%. From the body sizes observed, the proportions of old, adult and immature individuals were approximately estimated at 57, 26, and 17% respectively. 3. Baiji showed a significant attraction to confluences and sand bars with large eddies. The present distribution range of the baiji is less than 1400 km in length in the Yangtze main river. Distances between the two nearest groups of baiji appear to be increasing. 4. Two typical sightings are described, in which surfacing and movements of baiji were recorded. Baiji were often found swimming together with finless porpoise. In the surveys they occurred in the same group in 63% of occurrences. Interactions between baiji and finless porpoise are described and discussed. 5. Human activities are the main threats to the baiji. Illegal electrical fishing accounted for 40% of known mortalities during the 1990s. Engineering explosions for maintaining navigation channels have become another main cause of baiji deaths. The last hope of saving the species may be to translocate the remaining baiji into a semi-captive reserve. known as the 'Baiji Semi-natural Reserve'. Copyright (C) 2003 John Wiley Sons, Ltd.

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中国拥有92466 Km2的各类高原湿地,具有湿地退化、过度放牧等相似特征,保护与利用矛盾突出。高寒湿地保护区尽管在制度上以核心区、缓冲区来约束当地的放牧等外来干扰行为,但在实际管理中却不能起到应有的作用。 本研究以四川若尔盖湿地国家级自然保护区为例,应用3S技术,建立保护区多功能动态分区工作流模型,通过不同植被类型的识别和空间特征分析、不同动物类群在上述植被生境中的时空分布特征分析、保护区主要干扰因素的时空分布特征分析,突出对保护区主要保护对象(湿地生态系统)的保护,对保护区进行管理分区,依据野生动物利用特征和植被生长特征对核心区进行年周期动态利用,缓解保护与发展的矛盾,促进保护区的优化管理。 应用归一化植被指数(NDVI)与植被盖度的相关性,将归一化植被指数(NDVI)转化为植被盖度指数(MDVI),结合保护区牧场划分和时空利用特征专家经验,结果表明,MDVI值在1-139之间主要代表着水体、裸地、沙地等;MDVI140-256为草地和高山灌丛;MDVI210是当地夏牧场和秋冬牧场的划分区间值。 合理的区划需要资金、技术和政策的支持,为保证保护区多核心动态分区的实施,本研究提出了生态工程、牧业发展方式转变、湿地特色产业发展、湿地政策、社区参与和科技支撑等六大保障措施。 In China, 92466 Km2 highland or frigid wetlands are (were) facing major management problems, such as wetland degradation and overgazing. Conflict between conservation and utilization on those wetlands can be found anywhere today. Although many nature reserves have been setup for protection of frigid wetland, and core and buffer zone has been declared to forbid any kinds of disturbance, local farmers still use these areas for grazing. As an example by Sichuan Roige Wetlands National Nature Reserve(SRWNRR), we set up a 3S flow model to analyze the character of year-round distribution patters of vegetation, wildlife, and grazing. Combined and overlapped these characters together, we select multi-core zone and buffer zone, then define a dynamic management period in different zone to optimize protection wetland in the reserve. Normalized Difference Vegetation Index(NDVI)is highly related with coverage of vegetation. When convert NDVI to MDVI (coverage index, 1-256), index 139 and 210 can be as inflexion to distinguish among water/sand/bared land, summer pasture, and autumn / winter pasture. We use these to select different layers and analyze grazing pattern. To be more realistic, we put forward some strategies to support our multi-core and dynamic management of wetland in Roige, including ecological restoration engineering, changing of stock raising industry, changing of wetland policy, community based management and technology renovation supports.

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大熊猫(Ailuropoda melanoleuca)是我国特有的濒危野生动物之一,迁地保护已经成为大熊猫物种保护的一个重要方面。当前大熊猫圈养种群数量增长很快,但是其“多雄配一雌”的交配(配种方式),以及生产过程中记录遗失等原因,造成圈养种群普遍存在亲子关系不清、谱系混乱等问题。为了加强遗传管理,有必要进行亲子关系鉴定、完善谱系;还需要检测种群的基因多样性水平,并在此基础上提出相应的遗传管理建议。 本研究应用9个具有高度多态性的大熊猫微卫星标记,对来自成都大熊猫繁育研究基地2006和2007年度出生的17只大熊猫幼崽及其全部候选父母共37个样品做了基因型分析;然后应用最大似然法,判断幼崽的父-子关系。同时,还对来自卧龙大熊猫保护研究中心的31只大熊猫个体也做了基因分型。将两个种群的数据进行比较:1)等位基因多样性和杂合度水平;2)通过F统计法,分析两个种群的遗传分化水平;3)通过遗传距离法,对所有个体进行聚类分析。 研究结果表明: 1)在母子关系不清的情况下,9个微卫星标记联合的父亲鉴定排除概率E为0.940090;而在母子关系确实的条件下,E= 0.993933。由于本研究中所有后代的母亲都是清楚的,因此这9个微卫星位点能够有效用于圈养大熊猫的亲子鉴定。似然法分析也表明,本研究所获得的亲子鉴定结果置信度在95%以上。 2)2005年种源交换后,成都大熊猫的等位基因多样性和杂合度水平都略高于卧龙种群(但没有达到显著水平),两个种群间的遗传分化水平也有所降低。但是,与卧龙相比,成都种群面临较大的近交压力。 基于以上研究结果,我们建议:进一步加强种源交换和基因交流,把两个种群当作一个遗传单元(MU)来进行管理。 Giant panda (Ailuropoda melanoleuca) is one of the endangerd wildlife endemic to China, and the ex-situ breeding become more and more important for the conservation of this speices. Although the captive population is expanding rapidly, the uncertainty occurs because the paternities of cubs are not clear due to the breeding pattern of “multiple male to single female,”as well as the records lost, resulting in errors in the studbook. For this reason, the paternity of the cubs and the genetic diversity of the captive giant pandas should be tested carefully to get information for the genetic management in the future. 9 polymorphism microsatellite markers were used to do paternity assignment for the 17 cubs born in 2006 and 2007 from Chengdu Research Base for Giant Panda Breeding (CGB) based on the maximum-likelihood methods. A total of 37 individuals were sampled, including all the candidate dams and sires. These samples were also used for comparing with 31 individuals sampling from Wolong China Research and Conservation Center for the Giant Panda (WCG). The comparing indexes were: 1) Allelic diversity and heterozygosity; 2) Genetic differentiation based on F-statistic; 3) Cluster analysis based on genetic distance. The results show that: 1) If the mother is unkown, the combined exclusion probability using these 9 loci is 0.940090. If the mother is known then the exclusion probability is 0.993933. Since the dam-offspring relationship is known in captive populations, the results could resolve unknown paternities in the study. And the confidence level of the results is 95% based on the likelihood methods. 2) The allelic diversity and the heterozygosity of CGB were higher than WCG (n ot significant), and the genetic differentiation was reduced a little since the genetic exchange between two populations in 2005. However, the population of CGB will be threatening by inbreeding seriously than that of WCG. From above, we suggest to reiforce the genetic exchange and geneflow between CGB and WCG, and these two populations should be regarded as one genetic management unit (MU).