49 resultados para biodiversity conservation

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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The Hainan gibbon (Nomascus hainanus) is one of the most endangered primates in the world, confined to mature natural forest in Hainan Island, China. We assessed changes in habitat condition on the island between 1991 and 2008, using vegetation maps generated by remote-sensing images. We defined forest suitable for gibbons based on composition, tree size and canopy cover. During the 17-year period, the area of suitable gibbon forest decreased by 540 km(2) (35%) across the whole island, and by 6.3 km(2) (7%) in the locality of the sole remaining gibbon population at Bawangling National Nature Reserve. The forest patches large enough (>1 km(2)) to support a gibbon group decreased from 754 km(2) to 316 km(2) in total area, and from 92 to 64 in number. Suitable natural forest was mainly replaced by plantations below 760 m, or degraded by logging, grazing and planting of pines above 760 m. Meanwhile, forests in former confirmed gibbon areas became more fragmented: mean area of patches decreased by 53%. We mapped the patches of natural forest in good condition which could potentially support gibbons. We recommend a freeze on further expansion of plantations between core patches at Bawangling, Jiaxi-Houmiling and Yinggeling Nature Reserves in accordance with forest protection regulations; establishment of nature reserves in currently unprotected natural forest patches elsewhere in line with the local government's nature reserve expansion policy; and active natural-forest restoration between remaining fragments at Bawangling. (C) 2010 Elsevier Ltd. All rights reserved.

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middle and lower reaches of the Yangtze River, China. It is the only freshwater population of porpoises in the world and is currently listed as Endangered by IUCN. In November and December 2006 we used two boats and line transect methods to survey the entire current range of the population, except for two lakes (Poyang and Dongting). Sighting results were similar for both boats, so we pooled all data and analyzed them using two line transect models and a strip transect model. All models produced similar estimates of abundance (1111, 1225 and 1000). We then added independent estimates of the number of porpoises from the two lakes for a total estimate of approximately 1800 porpoises. Our findings indicate that the population continues to decline and that its distribution is becoming more fragmented. Our current estimate in the main river is slightly less than half the estimate from surveys between 1984 and 1991 (which was probably an underestimate). We also found an apparent gap in the distribution of porpoises between Yueyang and Shishou (similar to 150 km), where sightings had previously been common. Continued threats to Yangtze finless porpoises include bycatch in unregulated and unselective fishing, habitat degradation through dredging, pollution and noise, vessel strikes and water development. Immediate protective measures are urgently needed to ensure the persistence of finless porpoises in the Yangtze River. The survey design and analytical methods developed in this study might be appropriate for surveys of cetaceans in other river systems. (c) 2008 Elsevier Ltd. All rights reserved.

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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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植物生态学特性诸如植物的分布特征、与生境的关系、生物学特性、繁殖成功特点及其影响因素等方面的详细资料是研究珍稀植物种群结构和动态以及开展保育生物学研究的基础。 黄龙沟草本植物群落具有较为丰富的植物种类。在所调查样方中(N=662)共有维管植物124种,分属于37科91属,有54个中国特有种。其中兰科植物多达21属33种,中国特有种有12个,新种一个。如此众多的地生兰科植物聚集在面积不到1平方千米的沟内,而且部分兰科植物种类在沟内形成优势草本群落,这在中国地生兰的分布区域中是不多见的。大多数物种,包括兰科植物在内,出现的频率都较小,并且分布不均匀。种间关联分析和相关分析表明黄龙沟优势兰科植物可以分为两组。一组包括无苞杓兰、黄花杓兰、二叶根茎兰、广布小碟兰、少花鹤顶兰和西藏杓兰,主要分布在光线充足但又具有一定遮阴条件的环境中;另一组包括筒距兰、沼兰、珊瑚兰、小斑叶兰、布袋兰、小花舌唇兰和小叶对叶兰,它们主要分布于荫蔽的环境中。这些兰科植物在组内大多呈现显著的正相关关系,组间大多呈现显著的负相关关系,说明黄龙沟兰科植物在资源利用方式上可能产生了分化。 黄龙沟兰科植物主要分布在两种生境中,即钙化滩流地和一小片森林中。在这两种生境中微环境条件以及兰科植物的种类组成、数量特征和分布格局的差异都很大。钙化滩流地的兰科植物种类数目和每个样方中包含的兰科植物种类数目都比森林生境中的高。钙化滩流地中发现有30种兰科植物,六种最为常见的是无苞杓兰、黄花杓兰、西藏杓兰、广布小碟兰、二叶根茎兰和少花鹤顶兰,它们的密度与树木盖度呈负相关关系。森林生境中有21种兰科植物分布,其中筒距兰和斑叶兰出现最多,其密度与树木盖度呈正相关关系。光照强度可能对兰科植物的分布起到重要的决定作用。兰科植物彼此之间对繁殖成功以及植株间建立的相互促进作用以及土壤中高的钙含量很可能是形成黄龙沟兰科植物多样性的重要原因,而钙化滩流地中的溪流对建立和维持兰科植物生存所必须的稳定环境条件起到至关重要的作用,如果随意改变水流的方向或减少水流的流量,将给某些兰科植物带来灾难性的后果。 黄龙沟钙化滩流地中斑块的大小对物种数(含兰科植物)具有强烈的影响,即斑块越大,所包含的物种数量越多。物种-面积关系符合幂函数方程S=cAZ的规律。中等尺度的斑块(1-10 m2)包含的物种数(含兰科植物)的增长速度最快,而在斑块面积大于10 m2时,物种数增长速度最小。 少花鹤顶兰是多年生、多次结实的具有克隆能力的地生兰科植物,是中国特有种。黄龙沟少花鹤顶兰每个花序的平均花朵数为3(1-7)朵。叶和花的形态指标在年季间无显著变异。2005-2007年3年间的开花物候没有明显的差异,花期始于6月中旬,于7月底至8月初结束,持续约6-7周,80-90%的花在7月初的开花高峰期开放,属花集中开放模式。花寿命与是否授粉密切相关,成功授粉的花寿命比没有授粉的花寿命短。少花鹤顶兰是自交亲和的,但其结实完全依赖于两种熊蜂的传粉,不存在自动自花授粉和无融合生殖现象。柱头可授性和花粉活力可维持15天左右。繁殖成功率年季间的变化很大,并表现出逐年下降的趋势,花粉移走率为18-51%,自然结实率为10-36%。繁殖成功与开花物候之间的关系不显著,但与某一特定时刻的开花数量(密度)有关。生境对少花鹤顶兰的形态和繁殖成功率有显著的影响。在荫蔽生境中的个体比开阔地中的个体大,但繁殖成功率却低于开阔地的。花序密度(丛的大小)对少花鹤顶兰繁殖成功的影响比较复杂,不同大小的丛,对花粉移走率的影响格局和方式不同,而对结实率几乎没有影响。花序大小对繁殖成功率没有显著的影响。花位置对繁殖成功的影响在不同大小的丛中具有不同的格局,在最小的丛中,花位置对雄性和雌性繁殖成功的影响都很显著,但在最大丛中都不显著。边缘效应对少花鹤顶兰和广布小碟兰的繁殖成功有显著的影响,花粉移走率和结实率均随离栈道的距离增加而增加。在离栈道10米以内的植株受到的影响最为严重。这种影响可能是由边缘效应和在栈道上的游客共同作用下,对传粉者产生了干扰,导致传粉者的行为改变所引起的。如果这种边缘效应是一个普遍现象的话,那么在进行自然保护区设计时,应该对这种效应加以重视。

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摘要 神农架有着丰富的生物多样性和相对完整的森林生态系统,锐齿槲栎(Quercus aliena var. acuteserrata)是该地区落叶阔叶林重要的建群种之一,是其山地植被垂直带上的一个重要类型,对维持生态系统的稳定和水土保持具有重要意义。本论文主要研究了影响锐齿槲栎种群更新的一些重要因素以及探讨了神农架地区生物多样性的保护对策。 锐齿槲栎种子雨时空分布格局的研究结果表明:不同样地间种子雨的密度差别很大。树木的不同空间方位及种子的不同性状(被昆虫侵害、未发育成熟和有活力)在种子雨密度上的差异都极其显著。但在所研究的距离范围内(2-6m),与母株的距离对种子雨的密度影响不明显。相关性分析显示,样地中的种子雨空间分布与幼苗分布没有直接关系。实验中还发现,被昆虫侵害的种子较早下落,种子雨与落叶时间的不同步性有利于锐齿槲栎幼苗的建成。锐齿槲栎种群的结实存在明显的大小年现象,其结实周期约为2年。 动物对种子的散布与传播是影响锐齿槲栎种群更新的重要因素。在研究小型啮齿目动物对锐齿槲栎种子传播影响的实验中,用样方内布置铁夹的方法共捕获8种小型啮齿目动物,隶属3科、4属。实验结果还证明,不同林型和不同时间段(种子下落高峰期和种子基本落完时期)内小型啮齿目动物的捕食活动规律不同,林下灌木层类型对动物取食橡子和搬运距离也有一定的影响。 光对锐齿槲栎幼苗更新影响的研究结果表明,锐齿槲栎在林窗及林下都有大量的幼苗,而其幼树却很少。坡向对锐齿槲栎种群的更新有重要影响,光照好的东南坡上的更新情况明显比光照较少的西北坡好。光照梯度处理实验证明,光照强度影响锐齿槲栎幼苗的资源分配方式和比例,一定的遮荫环境更有利于锐齿槲栎幼苗的生长。 米心水青冈林(Fagus engleriana)和锐齿槲栎林在神农架地区广泛分布,两者分布的海拔范围比较相近,并形成一定面积的混交林。通过典型样地调查以及对苗木光合作用与资源分配的研究,结果表明:这两个树种具有不同的光利用策略,米心水青冈比较耐荫,林下更新较好,而锐齿槲栎林下更新不良,在光照较好的林窗下及次生裸地上更易更新。 神农架保护区是我国建立较早的以保护森林生态系统为主的自然保护区,是是联合国人与生物圈的保护地区之一,具有重要的生态价值和科研价值。保护区的建立对该地区的生物多样性保护发挥了重要的作用,但仍然面临着种种威胁。通过对神农架自然保护区当地社区的基本情况进行实地调查,分析结果表明,当地社区经济发展与生物多样性保护的矛盾比较突出,人类活动的干扰使景观破碎化呈增加趋势,整个生态系统比较脆弱。针对以上种种问题,建议加快制定有关保护区管理的法律;建立国家生态效益的补偿机制;推动实施社区共管;加强科研与区域生物多样性保护网络的协作;发展特色经济;加强能力建设,促进当地社区社会经济的全面发展。

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P> Widespread hunting throughout Amazonia threatens the persistence of large primates and other vertebrates. Most studies have used models of limited validity and restricted spatial and temporal scales to assess the sustainability. We use human-demographi

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The anadromous Chinese sturgeon (Acipenser sinensis), mainly endemic to the Yangtze River in China, is an endangered fish species. The natural population has declined since the Gezhouba Dam blocked its migratory route to the spawning grounds in 1981. In the near future, the completion of the Three Gorges Dam, the world's largest hydroelectric project, may further impact this species by altering the water flow of the Yangtze River. Little is currently known about the population genetic structure of the Chinese sturgeon. In this study, DNA sequence data were determined from the control region (D-loop) of the mitochondrial genome of adult sturgeons (n = 106) that were collected between 1995-2000. The molecular data were used to investigate genetic variation, effective female population size and population history of the Chinese sturgeon in the Yangtze River. Our results indicate that the reduction in abundance did not change genetic variation of the Chinese sturgeon, and that the population underwent an expansion in the past. AMOVA analysis indicated that 98.7% of the genetic variability occurred within each year's spawning populations, the year of collection had little influence on the diversity of annual temporary samples. The relative large effective female population size (N-ef) indicates that good potential exists for the recovery of this species in the future. Strikingly, the ratio of N-ef to the census female population size (N-f) is unusually high (0.77-0.93). This may be the result of a current bottleneck in the population of the Chinese sturgeon that is likely caused by human intervention.

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A total of 38 Amiota (s. str.) species (about 40% of the world total) are reported from southern China, with descriptions of 23 new species, i.e. sinuata species-group: aculeata Chen and Aotsuka, sp. nov., subsinuata Chen and Aotsuka, sp. nov., xishuangbanna Chen and Aotsuka, sp. nov.; basdeni species-group: brevipartita Chen and Gao, sp. nov., curvispina Chen and Gao, sp. nov., lipingae Chen and Gao, sp. nov., huae Chen and Gao, sp. nov., longispina Chen and Gao, sp. nov.; taurusata species-group: asymmetrica Chen and Takamori, sp. nov.; femorata Chen and Takamori, sp. nov., yixiangensis Chen and Takamori, sp. nov.; alboguttata species-group: ailaoshanensis Chen and Watabe, sp. nov., arcuata Chen and Watabe, sp. nov., dehiscentia Chen and Watabe, sp. nov., jizushanensis Chen and Watabe, sp. nov., latitabula Chen and Watabe, sp. nov., luguhuensis Chen and Watabe, sp. nov., nozawai Chen and Watabe, sp. nov., paraspinata Chen and Watabe, sp. nov., shangrila Chen and Watabe, sp. nov.; and ungrouped: fuscicata Chen and Zhang, sp. nov., wangi Chen and Zhang, sp. nov., wuyishanensis Chen and Zhang, sp. nov. A key to all species from southern China is provided. The Amiota fauna of southern China at the species-group level is compared with that of six geographic regions. The subgenus Amiota is assumed to have originated and produced many species-groups in the Oriental region of East Asia, and then the basdeni, alboguttata and rufescens species-groups might have spread to Europe and North-Central America throughout the Palearctic region of East Asia and both the apodemata, sinuata and nagatai species-groups to tropical regions of South-East Asia.

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Eleven polymorphic microsatellite loci were characterized for the endangered conifer Taxus yunnanensis. Eight loci were isolated through SSR-anchored PCR, one locus was developed by cross-species amplification tests, while the last two loci were obtained

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We find no genetic variation at 550bp of mtDNA control region among 55 Hainan Eld's deer in an island population that has suffered recent population contractions. Congeneric species show high levels of variation at this locus. We use a simulation approach to test the likelihood of various bottleneck scenarios, and show, in the context of what is known about the recent demographic history of this population, that there are credible scenarios for a bottleneck driven by hunting pressure in the 1960s that could account for the lack of variation at this locus.

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Surveys on migratory waterbirds and their habitats at Lashihai Lake, China, were conducted from October 1999 to April 2000. Five fixed points, representing different degrees of habitat disturbance and quality, were selected around the lake. We used counts (n = 30) to compare diversity and abundance of waterbirds at each point and evaluate the effects of habitat disturbance. The distribution of waterbirds was affected by disturbance, with snore than one-third of the total species and nearly half of the total individuals occurring at the least disturbed point. Species richness was weakly and abundance was strongly correlated to habitat disturbance, but not to habitat quality. Habitat destruction and use of canoes were prominent at the lake. Naxi ethnic fishermen (n = 37) were interviewed. They caught 570 waterbirds between October 1999 and March 2000 in fishing nets. An estimation of the total number of waterbirds been trapped on the lake is 6164. Diving species were most susceptible. Conservation measures that should implement immediately include the cessation of habitat destruction, better plan for the development of tourism, a reduction in the number of canoes and zoning of the non-fishing area. (C) 2002 Elsevier Science Ltd. All rights reserved.