185 resultados para eastern China
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Many systematic relationships among Chinese white-toothed shrews of genus Crocidura are presently unresolved. In this paper, a taxonomic revision of Crocidura from Southern China is presented. We studied 338 specimens from Burma, China, Korea, Pakistan, Turkey, Middle and Central Asia, and Russia (Appendix I), 285 of which had complete skulls that were analyzed with principal component and discriminant analyses. Results indicated that 6 species of Crocidura can be recognized in South China. C. fuliginosa occurs in Southwestern and Eastern China, C. attenuata is broadly distributed throughout Southern China, and C. horsfieldii is restricted to the southern part of China. C vorax and C. rapax, usually placed as synonyms of the European C russula, are recognized as 2 valid species whose ranges overlap in Southwestern China. C. shantungensis of Eastern Asia extends to the northern part of Southern China and is distinct from C. suaveolens and C. gmelini of Middle and Central Asia, respectively.
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Bryodrilus fuscistriatus, a new enchytraeid species from Mt. Changbaishan, Jilin Province, north-eastern China, is described. It is characterized by brown epidermal glands, 7 pairs of preclitellar nephridia, poorly-developed clitellar glands, spermatheca with 2 sessile globular diverticula, and a long sperm funnel with a very broad collar. It is similar to the Alaskan B. tunicatus Dozsa-Farkas & Christensen, 2002 in possessing two diverticula in the spermathecal ampulla and the origin of the dorsal vessel, and the Chinese B. longifistulatus and B. macrotheca Xie et al., 2000c in body size, long sperm funnel and undeveloped clitellar glands, but it differs from B. tunicatus by the presence of brown-striped epidermal gland cells in III-V, a poorly-elevated clitellum, the absence of copulatory glands in XIII-XIV, the regular outline of coelomocytes, and 7 pairs of preclitellar nephridia; from B. longifistulatus and B. macrotheca by the shape of spermatheca, the color of epidermal gland cells, the position of the first pair nephridia, and the origin of dorsal vessel.
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Loaches of the genus Niwaella, family Cobitidae, are distributed only in East Asia. At present only in Japan and South Korea have fishes of the genus Niwaella been found. Herein we revise the genus Niwaella in China. Son and He ( 2001) transferred the species Cobitis laterimaculata to the genus Niwaella, but their specimens were not N. laterimaculata, but a new species, N. longibarba sp. n., collected from Cao'ejiang River, Huangzezhen, Chengxian County, Zhejiang Province. The new species is distinguished from N. laterimaculata by its colour pattern of a row of slightly large, and long, scattered dark brown vertical bars on the dorsolateral surface, two or three striations on the caudal fin, and long barbels and undeveloped mental lobes. In this paper we also describe another new species, N. xinjiangensis sp. n., collected from Xinjiang River, Guangfeng County, Jiangxi Province, May 1990, with diagnostic colour pattern of 17 - 20 large and long, dark brown vertical bars on the dorsolateral surface, a dark stripe or rounded black spots along the lateral midline and some blotches below the lateral midline; it is a large-sized species, with shorter barbels, and longer caudal peduncle. Thus five species of the genus Niwaella are known, three are endemic to eastern China and two are endemic to either Japan or South Korea.
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Salt marsh-tidal creek systems as a coastal geomorphological unit represent an important natural resource. The present study on Jiangsu salt marshes, eastern China, shows that variations in tidal current velocities in salt marsh creeks are controlled by the local tidal wave characteristics and the bed slope and elevation of the salt marshes and creeks. Likewise, the tidal currents modify the geomorphology of the salt marsh-tidal creek systems by transporting sediments and causing erosion/deposition. Storm events, which appear to have cyclical changes in their intensity relating to sunspot activities, can affect the geomorphic evolution of such systems. Further, in response to accelerated sea-level rise, accretional rates on salt marshes may increase. The tidal creeks have the function of transporting water and sediment onto the salt marsh surface; further, the energy of tidal currents and waves are dissipated within the salt marsh-tidal creek system. Hence, this coastal system has a potential value for coastal protection.
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Based upon the effect of land-sea interaction on the paleomonsoon variation and the time series of climatic proxy-indicators, the historical Asian monsoon variation over the last 130,000 and 18,000 years has been reconstructed with an emphasis on the basic characteristics of summer monsoon circulation. The monsoon-climatic cycles and associated model of environmental development over the central and eastern China are proposed and the mechanism of paleomonsoon variation of China preliminarily discussed. The variation of East Asian monsoon circulation should be regarded as a regional result of both solar-radiation changes and the global glacial-interglacial cycles. The episodic uplifting of the Qinghai-Xizang Plateau since the late Miocene has to a large extent controlled the forming and evolution of the paleomonsoon circulation of China.
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本论文研究的创新之处是在高分辨率的地层层序上选定3米X3米的工作剖面,逐层采集标本,定量研究山旺中新世古气候的变化过程。主要有以下新的认识和结论: 植物化石的数量和种类在地层层序上的变化很大。第5层、第6层、第7层、第13层、第15层和第16层的标本丰富,可以进行CLAMP分析。 第5层、第6层和第7层的泥岩中保存有丰富的植物化石,运用荧光显微分析技术可以清晰地观察到泥岩中植物的气孔和表皮细胞形态。 山旺地区中新世年均温(MAT)在9.5℃和11.3℃之间。较热月份平均温度(WMMT)在19.9 ℃和22.4 ℃之间。生长季月数(GSL)为5.9--6.9个月。生长季节平均降水量(MGSP)为860--1770 mm。生长季月平均降水量(MMGSP)为152--253mm,生长季三个连续最湿的月份降水量(3-WET)为530--920mm,三个连续最旱的月份的降水量(3-DRY)为286--687mm。相对湿度(Rel. Hum)在73%以上,高达80%。特殊湿度(q-Specific Humidity)在5.9--6.7之间,热熵值(H-Enthalpy)为298.5--304.5。 气候参数在地层层序上存在变化。CLAMP分析的结论与最近亲缘种分析(NLR)的结论相似。CLAMP分析的年均温比现在山旺的年均温12.5℃低,比同层的线性分析结果低3℃。与海底有孔虫氧同位素的研究结论一致。山东山旺中新世古气候的研究可以作为中中新世全球气候变化研究的一个标尺。
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上新世时期是地球环境发展变化过程中由温暖的中新世向冰期-间冰期交替出现的更新世的过渡时期,研究上新世的气候有助于研究现代全球气候变化趋势。我国上新世植物群研究不多,尤其缺乏早上新世植物群的研究。在研究化石植物群的过程中,叶角质层的信息通常被忽视。迄今,我国古气候的定量研究主要集中在山东山旺和云南地区,研究的主要是中新世和晚上新世的古气候,早上新世气候的定量研究国内外都未见报道。 本论文以采自浙江中部嵊州地区硅藻土中的植物叶和果实为材料,通过光学显微镜、荧光显微镜和扫描电镜观察,对提取的化石叶角质层和叶结构进行研究,对比研究现代相关类群植物的叶片,确定了化石植物类群计15科24属(或亚科)34种。同时参照现代植物分布,恢复了早上新世嵊州地区古植被情况,进一步运用共存分析(Co-existence Approch)定量重建了当时的古气候,得到古年均温、古年较差和古年降水量等7个参数。 研究表明,叶结构和叶角质层可以应用于化石植物类群的鉴定。光学显微镜和荧光显微镜下可以获得的信息有:气孔、表皮细胞形状及大小、表皮细胞垂周壁、分泌结构、表皮毛或毛基等。扫描电镜观察的是叶表皮细胞表面的情况,如细胞外壁是否被蜡质以及蜡质的交结情况,气孔外壁是否增厚呈环等。 经化石植物类群鉴定,早上新世(约4Ma)嵊州地区植被属亚热带常绿阔叶林。推测:该地区当时存在一个较大的湖泊,湖泊边缘水中生长有菱角,湖泊周边可能有海拔超过1400m的山地。 常绿阔叶林主要成分是壳斗科植物,其中青冈属植物可能是建群植物。自低海拔到高海拔地区都有分布的是:栎属、栗属、桤木属植物,青杨梅。低海拔地区(<600m)分布的植物有:海南锥,樟。中低海拔地区(300-1000m)分布着:柯属、黄杨属植物,水青冈,海南油丹,江南油杉,福建柏。中高海拔地区(>700m)分布有:高山栎、黄肉楠属植物,米心水青冈,榉树,建始槭,天台鹅耳枥和昌化鹅耳枥。除了上述类群,林中还散布着鼠李属、杜鹃花属和冬青属的植物,豆科崖豆藤属植物则缠绕一些较大乔木生长。另外,在一些土壤、有机质易堆积的洼地生长有竹林,山地贫瘠的地方生长着柏属植物。 嵊州早上新世化石植物群反映的植被同浙江地区现代植被相似。第三纪浙江地区从针叶林或阔叶树为主的针-阔叶混交林过渡到常绿-落叶阔叶林,再发展为常绿阔叶林。 依据23个植物类群分析获得7个古气候参数:年均温17.7-21.4°C,最热月均温22.2-27°C,最冷月均温8.4-13.4°C,年较差12.1-15.3°C,年降水量1136-1869.9mm,最大月降水量211.8-283.3mm,最小月降水量20.3-36.8mm。 对比现代嵊州地区气候参数,早上新世嵊州地区年降水量略高于现代,年均温比现代高1.3-5°C,年较差为12.1-15.3°C。早上新世期嵊州地区四季气温比现代平稳。
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样带是沿全球变化某一驱动因素的主要梯度而设置的由一系列研究站点构成的区域,被认为是研究全球变化与陆地生态系统关系的最有效的途径。而模型研究是全球变化研究中不可或缺的手段。本文即采用模型研究方法研究中国东北温带样带(NECT)区域,试图揭示温带生态系统对于全球变化(尤其是降水)的反应机制。
中国东北温带样带(NECT)位于42°N - 46°N,108°E - 132°E,长约二千多公里,是最早被列入GCTE的四条样带之一,从东到西有明显的湿度梯度,被认为是温带区域研究水分梯度的代表性样带。本文研究主要集中在:
1.NECT中环境数据库的建立,本文采用EIS作为数据管理系统。由于EIS管理空间数据的特点是根据确定的地理坐标来提供空间定位,因而每一环境因子的属性值分布都有确定的地理坐标与其对应,特别适合于样带这种研究区域较大,同时又要求有精确空间定位的区域。NECT环境数据库包括地形、气候、植被、土壤、土地利用、水文、孢粉数据及社会经济等分库、本数据库力图提供各环境因子的各种属性值而代替仅仅提供类型值。
2.NECT中PFTs的划分PFTs的划分被认为是建立DGVM的前提。本文认为PFTs的划分是模型研究中一个尺度上升过程的结果,不同的尺度,不同的研究目标导致不同的PFTs的划分。在NECT区域中,考虑植被对全球变化中降水因子的不同反映机制,采用生活型、高度、耐旱特性、叶子大小、叶子季相、主根深度和木质化程度等指标根据- TWINSPAN和FCLUS进行划分,得到以下9种NECT区域中植被功能类型:常绿针叶树种、落叶针叶树种、落叶阔叶树种、落叶小叶灌木、落叶小叶半灌木、落叶强旱生半灌木、多年生中旱生草本、适应旱生环境的多年生草本和多年生强旱生草本。对NECT区域中PFTs的DCA分析表明降水是控制PFTs在NECT区域中分布的主要环境因子。在代表景观层次的长白山PFTs的划分中,则采用树种有记载的最大寿命、最大胸径、最大树高、各树种生长参数、树种自然分布区内>5℃的有效积温的最小值和最大值、耐阴、耐旱、喜肥特性、树种的扩散更新,就地下种更新和萌条更新能力参数及叶子大小和类型等指标采用上述软件得到的以下PFTs:即不耐荫阔叶树种、耐荫阔叶树种、耐荫针叶树种和不耐荫的阳生针叶树种。
3.NECT中BCM模型的建立和预测 本文认为土壤水是决定SPC系统水分状况的直接指标。而均衡土壤水分剖面代表了土壤水的多年平均状态,因而本文以Watershed模型为基础,模拟NECT区域中任意一点的均衡土壤水分剖面(精度为每经纬网格32×48个点);然后根据这个均衡水分剖面用计算LAI子模型确定该水分剖面所能支持的LAI;进而根据这个LAI由Biome等模型划分出Biome在NECT中的分布。全球变化的结果将改变区域中任意一点的土壤水分状况,从而影响植被的LAI,进而导致Biome的改变。本模型成功的模拟了LAI和Biome在NECT区域中的分布,利用85-90生长季每月平均的NDVI作相关检验表明除5月份以外,相关系数都>0.7,而5月份也达到0,6457,都达到了极显著的程度。尤为重要的是,模型对于不同植被类型的NDVI与LAI的对应关系有良好的模拟,如针叶林的LAI在相同的NDVI值下明显比阔叶林小,因而模型模拟的LAI在NECT东部针叶林分布区LAI值比针阔混交林明显偏小,而与Spanmen等(1990)所提出的针叶林叶面积指数与NDVI关系非常一致。模型的预测显示:(1) T+20C (PET+15%),Precipitation+20%,LAI总体上变化不大,且空间变化呈现复杂性,总体上表现出草原植被LAI减少,而森林的LAI增加;Biome层次表现出针阔混交林和矮草原面积扩大,针叶林和森林草原面积减少,其中对于该情形下变化最为明显的是针叶林和森林草原。NECT东部区域发育在沙性土上的植被的LAI明显增加,而科尔沁沙地植被的LAI则维持不变。(2)T+40C (PET+30%),Precipitation+20%,LAI总体上将减小0.14,但空间分布不均。东部森林区域LA1将维持不变或增加(主要为针叶林),草原植被LAI仍表现出减少趋势;在Biome层次上则表现出草原面积的扩大。对于第一种情形下LAI有增有减的森林革原地区则表现出减小的一致性,总体来说,第二种情形比第一种情形表现出相当的干旱性。从对两种全球变化情形的反应来看,针叶林和森林草原是NECT中对全球变化驱动因子温度和降水的敏感植被类型;丽科尔沁沙地植被表现出相当的稳定性,表明该沙地的敏感性主要是由于人类活动这个因子造成的。
4.NECT中景观层次NPP模型的建立和预测 景观层次之所以成为模型研究中一个独特的层次,是由于地形效应的存在。地形效应对于水、热。营养物质的进行重新分配,从而进一步控制了生态系统的分布。本文选择NECT区域中森林生态系统的代表性分布小流域一二道白河小流域为研究区域。首先,应用Sunlight模型来模拟小流域任意一点所截取的能用于光合作用的太阳辐射能。Sunlight模型充分考虑了由于栅格的坡度、坡向和遮蔽度对可照时间和太阳直射辐射的影响以及坡度和可祝度对太阳散射辐射的影响,并提供了消除大气状况从站点观察数据推测的方法,即太阳直射辐射转换系数Rb和太阳散射辐射转换系数R,结合植被的分布特性,得到IPR在小流域中的分布。结果表明,IPR在小流域中相差不大,与高程呈正相关。进而利用温度修正模型得到温度修正系数,平均为0.446,表明温度对NPP的限制效应比较大;而水分修正系数则通过Topmodel模拟每一栅格的地下水位,由这个地下水位通过前述Waterbalance模型模拟均衡土壤水分剖面,进而求出水分修正系数,平均为0.86,表明该流域水分状况良好,水分状况对NPP的限制性不强。模拟结果显示:海拔
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During a recent soil sample survey in Eastern China, a new entomopathogenic nematode species, collected from the Chongming Islands in the southern-eastern area of Shanghai, was discovered. Morphological characteristics of different developmental stages of the nematode combined with molecular data showed that this nematode is a new genus of Rhabditidae, and described as Heterorhabditidoides chongmingensis gen. nov., sp. nov., for that it shares more morphological characteristics with heterorhabditids than with ste-inernematids. For males, the papillae formula of bursa is 1, 2, 3, 3, with constant papillae number in the terminal group, stoma tubular-shaped and about 1.5 head width; cheilorhabdions cuticularized, esophageal collar present and long, median bulb present. For infective juveniles, EP = 90 (80-105) mu m, ES = 104 (92-120) mu m, tail length = 111 (89-159) mu m, and a = 19.1 (15-21). The percentages of the nucleotides A, T, C and G in the ITS1 regions of the new species are significantly different from those of heterorhabditids and other rhabditids. Molecular phylogenetic trees based on 18S rDNA and the internal transcribed spacer (ITS) sequences data revealed that the new entomopathogenic nematode species forms a monophyletic group, which is a sister group of the clade comprised of some genera of Rhabditidae. (c) 2008 Elsevier Inc. All rights reserved.
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The Yangtze River dolphin or baiji ( Lipotes vexillifer), an obligate freshwater odontocete known only from the middle-lower Yangtze River system and neighbouring Qiantang River in eastern China, has long been recognized as one of the world's rarest and most threatened mammal species. The status of the baiji has not been investigated since the late 1990s, when the surviving population was estimated to be as low as 13 individuals. An intensive six-week multivessel visual and acoustic survey carried out in November-December 2006, covering the entire historical range of the baiji in the main Yangtze channel, failed to find any evidence that the species survives. We are forced to conclude that the baiji is now likely to be extinct, probably due to unsustainable by-catch in local fisheries. This represents the first global extinction of a large vertebrate for over 50 years, only the fourth disappearance of an entire mammal family since AD 1500, and the first cetacean species to be driven to extinction by human activity. Immediate and extreme measures may be necessary to prevent the extinction of other endangered cetaceans, including the sympatric Yangtze finless porpoise ( Neophocaena phocaenoides asiaeorientalis).
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木材腐朽菌是生物多样性的重要组成部分,在森林生态系统中起着关键的降解还原作用;同时,木材腐朽菌还是重要的生物资源,与人类的生产与生活密切相关,具有重要的经济价值。因此,木腐菌一直是真菌研究的重点领域之一,然而过去对华东地区木腐菌的研究还非常薄弱,对华东地区木腐菌的种类和资源还缺乏清晰的认识。本文对华东地区不同森林生态类型中的木腐菌进行了广泛的调查采样,通过形态学、分子系统学和单孢融合交配实验,对华东地区的木腐菌多样性与资源进行了系统的研究,同时对具有重要经济意义和潜在应用价值的种类进行了菌种的分离保藏,并初步分析了华东地区木腐菌的区系特点。通过本论文的研究,提高了对华东地区木腐菌资源与多样性的认识,丰富了我国木材腐朽菌的种类,为控制林木病原菌、开发利用有益真菌资源提供了基本信息和科学依据。本论文的主要研究结论如下: 1.华东地区的木腐菌有3目13科92属270种,其中真菌新种6个,分别是:铁杉集毛孔菌Coltricia tsugicola Y.C. Dai & B.K. Cui,香榧嗜蓝孢孔菌Fomitiporia torreyae Y.C. Dai & B.K. Cui,拟囊状体大孔菌Megasporoporia cystidiolophora B.K. Cui & Y.C. Dai,菌索多年卧孔菌Perenniporia rhizomorpha B.K. Cui, Y.C. Dai & Decock,微小硬孔菌Rigidoporus minutus B.K. Cui & Y.C. Dai,浅黄芮氏孔菌Wrightoporia luteola B.K. Cui & Y.C. Dai;中国新记录种9个,分别是:紫多孢孔菌Abundisporus violaceus (Wakef.) Ryvarden,卡玛蜡孔菌Ceriporia camaresiana (Bourdot & Galzin) Bondartsev & Singer,撕裂蜡孔菌Ceriporia lacerata N. Maek., Suhara & R. Kondo,塔斯马尼亚集毛孔菌Coltriciella tasmanica (Cleland & Rodway) D.A. Reid,瑞克纤孔菌Inonotus rickii (Pat.) D.A. Reid,骨质多年卧孔菌Perenniporia minutissima (Yasuda) T. Hatt. & Ryvarden,灰硬孔菌Rigidoporus cinereus Núñez & Ryvarden,凹形栓孔菌Trametes ectypus (Berk. & M.A. Curtis) Gilb. & Ryvarden,变形干酪菌Tyromyces transformatus Núñez & Ryvarden。 2.利用分子系统学方法,确定了一些通过形态学研究难以鉴定或容易混淆的种类的分类地位,并对嗜蓝孢孔菌属、彩孔菌属和多年卧孔菌属进行了系统发育分析,发现木腐菌新种3个:Fomitiporia sp.、Hapalopilus sp. 和Perenniporia sp.。 3.华东地区的异担子菌为岛生异担子菌,并且存在两个生物种:T生物种和Y生物种。T生物种为腐生菌,Y生物种为兼性腐生菌,华东地区不存在多年异担子菌这一严重的森林病原菌。 4.华东地区的木腐菌种类丰富,组成复杂多样。优势科为多孔菌科,其次为锈革孔菌科,这两科的种类构成了华东地区木腐菌类区系的主体;优势属主要有多年卧孔菌属、多孔菌属、针层孔菌属和泊氏孔菌属。 4.华东地区木腐菌科的地理成分分为3类:热带亚热带成分,北温带成分和世界广布成分,以世界广布成分为主。属的地理成分分为5类:世界广布属,北温带分布属,热带–亚热带分布属,东亚–北美分布属,大洋洲–北温带分布属,以世界广布属和北温带分布属为主。种的地理成分分为8类:世界广布种,北温带分布成分,泛热带分布成分,亚–欧共有成分,东亚–北美共有成分,东亚–澳大利亚共有成分,东亚成分,中国特有种,以北温带分布种和世界广布种为主。 5.华东地区木腐菌的各主要区系成分均有分布,以世界广布成分和北温带成分为主,表现出明显的北温带性质,可能起源于北半球,华东地区木腐菌类的区系地理成分与其所处的地理位置、气候特点与植物区系的组成密切相关。此外,华东地区的中国特有种类也较为丰富,说明了华东地区木腐菌类的区系具有一定的独特性,也在一定程度上反映了华东地区生态环境条件的特殊性,而木腐菌的生长与环境条件和寄主树木种类有很大的关系。 6.华东地区的木腐菌资源非常丰富,林木病原菌有36种,其中新发现的病原菌有3种;野生的食用木腐菌有11种,野生的药用木腐菌64种,工业用木腐菌有28种。对其中的一种重要经济真菌——黄白多年卧孔菌进行了分离培养,找出了最佳生长条件:最适生长温度为25℃左右,相对最适pH值为5.5,相对最好的碳源为可溶性淀粉和葡萄糖,相对最好的氮源为酵母汁。
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依据线粒体上ND2和CO1两个变异较大的基因序列分析了香港地区香港湍蛙7种群、华南湍蛙1种群,以及大陆其他地区华南湍蛙7种群,戴云湍蛙1种群,武夷湍蛙1种群的系统发育关系,进而探讨香港湍蛙的遗传多样性、香港湍蛙特有性、如何确定香港湍蛙最佳保护单元以及这四种湍蛙的物种分类地位。
1. 香港湍蛙保护遗传学研究
香港湍蛙核苷酸传多样性较低,从其遗传多样性信息、单倍型网络分析、中性检验值以及岐点分布结果一致显示香港湍蛙很可能经历了瓶颈后的扩张,种群正在由一个较小的有效种群大小迅速增长, 有足够的时间通过变异用于积累单倍型的多态性, 而对于提高核苷酸多样化而言, 时间尚短(Nei M et al,1975,Avise J C,2000;李明等,2003)。
分子变异分析结果显示香港湍蛙种群间存在较多的基因交流,且系统发育树上各种群间交叉在一起,没有形成与地理单元相关的分支,而从其单倍型网络看,他们源于共同的祖先,是一个单系群,与地理单元间没有形成显著的遗传分化。因此应作为一个进化显著单元(ESU)。结合其与其他湍蛙发育关系及遗传距离以及野外采集信息认为香港湍蛙只在香港地区有分布,属于香港特有种。该物种内遗传多样性较低,又属于世界自然保护联盟红皮书中的近危种,同时也是《野生动物保护条例》中的受保护野生动物,且由于香港城市建设等使得其栖息环境受到威胁,因此在香港特别行政区应该受到重点保护。
从单倍型分布和核苷酸多样性可以看出大榄涌种群和城门种群具有较高的单倍型多样性和核苷酸多样性,应该作为保护的重点区域。
2. 华南湍蛙东、南沿海种群间系统关系
华南湍蛙分布广,各种群存在着丰富的遗传多样性信息且中部种群广西龙胜和湖南张家界种群核苷酸多样性明显高于其他边缘种群华南湍蛙。种群间几乎没有基因交流,且各种群间无共享单倍型,可见已形成了显著的遗传分化。各种群间遗传距离都较远,其中广东南昆山种群以及福建三港种群与其他种群距离最远,因此可以推测其他种群(广东深圳、香港大屿山、广西龙胜和防城以及湖南张家界种群)可能为独立进化的种群。但是否是一新种或一隐存种,还需要结合形态学进行更深入的研究。
本研究中无论从系统关系看还是从遗传距离看,大屿山种群与深圳种群最近,支持陈坚峰等将其定为华南湍蛙,即华南湍蛙新增一个分布点:香港大屿山。
系统树上广西防城种群(支B)与龙胜和湖南种群(支A)形成姐妹群。香港大屿山种群与深圳种群先形成姐妹群(支C),但却没有与其距离很近的广东南岭及南昆山种群(支D)形成姐妹群,可能粤北和粤中的环境及气候较复杂因此与粤南其他种群形成了明显的隔离。同时可以看出华南湍蛙种群遗传分化与地理距离没有显著的相关性。
3. 四种湍蛙间的系统关系
根据线粒体CO1基因建立四种湍蛙间的系统关系及其遗传距离,很清楚地看到,香港湍蛙与戴云湍蛙关系很近,而华南湍蛙则与武夷湍蛙较近。然而,戴云湍蛙同一个种群内部共有两个单倍型DY1和DY2,且两个单倍型间遗传距离大于DY1与香港湍蛙间遗传距离,更远远大于香港湍蛙种群内部的距离,即戴云湍蛙内部两个单倍型间遗传距离达到了种级水平,同样在系统发育树上这两个单倍型与香港湍蛙形成并系。但是,戴云湍蛙种内在形态上差异不显著。因此,其是否属于萌芽物种分化形成(budding speciation)或已经完全分化为两个不同的种值得进一步研究?
与戴云湍蛙香港湍蛙关系类似,从系统树上看华南湍蛙不形成单系,而是分成两个大支,与武夷湍蛙形成并系,且福建和南昆山的华南湍蛙与武夷湍蛙遗传距离远大于武夷湍蛙种内福建种群与浙江种群的遗传距离,达到了种级分化水平。由此,可以推断武夷湍蛙是有效种。系统树上广东深圳、香港大屿山、广西防城和龙胜以及湖南张家界种群与华南湍蛙福建及南昆山各种群间遗传距离已超出了种内各种群间的遗传距离,但是至于这一支是否应为另外一个种,有必要扩大采样,并结合核基因及形态信息进行进一步研究。
MtDNA of ND2 and CO1 gene were used to investigate genetic diversity of Amolops in Hongkong .We collected seven populations of A. hongkongensis,,one population of A.ricketti from Hong Kong and other seven populations of A.ricketti from East and South of Chinese mainland. As well as one population of A. daiyunensis and one population of A.wuyiensis Phylogenetic relationship were analyzed of four species. Discussed whether A.hongkongensis is an endemic species and how can we make the conservation and management decisions.
1. Conservation Genetics of A. hongkongensis
A. hongkongensis has a low nucleotide diversity, the results of genetic diversity, haplotype network, neutrality test and the mismatch distributions indicate that A. hongkongensis experienced a recent expansion after a bottle neck. They had enough time to accumulated haplotype diversity, but it’s too short to have a high nucleotide diversity(Nei M et al,1975,Avise J C,2000;Li et al,2003).
The result of AMOVA reveals that it has much gene exchange among the populations of A. hongkongensis. The clades of the phylogenetic tree were mixed together, no significant genetic differentiation among 8 populations and they share the same ancestor from the network analysis, these indicate that they are monophyly and should be protected as one ESU. Combined with the information of relationships of interspecies, genetic distance and distribution investigate, We conclude that A. hongkongensis is an endemic species of Hong Kong. Considering on the status of low genetic diversity in A.hongkongensis, and this species was listed in the IUCN red list as near threatened, as well as listed in the
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As a large conspicuous intertidal brown alga, individuals of Sargassum horneri can reach a length of more than 7 m with a fresh weight of 3 kg along the coasts of the Eastern China Sea. The biomass of this alga as a vital component in coastal water ecology has been well documented. In recent years, a steady disappearance of the algal biomass along the once densely populated coastal areas of the Eastern China Sea has drawn attention in China. Efforts have been made to reconstruct the subtidal algal flora or even to grow the alga by use of long-lines. As part of the efforts to establish an efficient technique for producing seedlings of S. horneri, in this investigation a series of culture experiments were carried out in indoor raceway and rectangular tanks under reduced solar irradiance at ambient temperature in 2007-2008. The investigation demonstrated that: (1) sexual reproduction of S. horneri could be accelerated in elevated temperature and light climates, at least 3 months earlier than in the wild; (2) eggs of S. horneri had the potential to be fertilized up to 48 h, much longer than that of known related species; (3) suspension and fixed culture methods were both effective in growing the seedlings to the long-line cultivation stage; and (4) the life cycle of S. horneri in culture could be shortened to 4.5 months, thus establishing this alga as an appropriate model for investigating sexual reproduction in dieocious species of this genus.
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Based on the study of palaeo-environmental evolution in the shelves of the Eastern China Seas, the concept of ''shelf desertization'' in the late stage of Upper Pleistocene is defined; the environmental background and evolutionary process of shelf desertization are analysed. Study on the records of subbottom profiling and the data of core samples from shelf areas revealed that during low sea-level stages, the sedimentary environment in the exposed shelf plains was dominated by aeolian depositional process under cold and dry climatic conditions, i.e. under the action of strong winter-monsoon winds. Parts of the exposed marine strata were disintegrated, and aeolian sand dunes were formed on the disintegrated marine deposits, from which the finer sediment grains were blown away by wind and deposited in the downwind areas to form the derivative loess deposits. Thus a desertization environmental system was formed in the exposed shelf plains of the Eastern China Seas.
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海洋锋面既是各种物理过程,如环流、上升流、混合等的结果,也是这些物理过程的指标,还是影响流场结构、海洋热量和动量交换、海气相互作用以及生物化学过程的重要因素。同时,海洋锋面研究还与海洋产业活动,如海洋渔业、环境保护、海洋倾废等密切相关,也是军事海洋学必须考虑的问题。所以,海洋锋面的研究也成为物理海洋学和海洋交叉学科研究中的一个重要内容。 本研究以中国东部近海(渤海、黄海、东海及南海北部)锋面的分布特征、变化规律、动力机制及对相应过程的影响为研究对象,以1985~2002年AVHRR Pathfinder的卫星海表面温度数据为基础,辅以POM模式,通过数据分析、模式验证和动力机制分析相结合的方法,既全面描述了中国东部近海锋面分布和变化的总体特征,又深入研究了三个典型锋面,即南黄海西部沿岸锋面、黄海暖流源区陆架锋面和东海黑潮陆坡锋面的具体特点,结果如下: 1,中国东部近海温度锋面分布状况的季节变化明显。冬季,锋面丰富,形状规则,位置稳定,可以明确区分出14条沿岸流锋面和暖流锋面。春季及夏初,锋区分布范围广,没有规则的锋面形态,也没有固定的发生区域,不能明确分辨出具体锋面,锋区大体按黑潮流域—长江河口沿岸区域—南黄海区域的方向和渤海—北黄海—南黄海的方向转移。夏季在沿岸区域产生潮汐锋,秋季则很少有锋面出现。对于冬季锋面的位置来讲,沿岸锋面的年际变化小,暖流锋面的年际变化大;受地形限制的锋面年际变化小,脱离地形控制的锋面年际变化大。 2,冬季山东半岛南部(即南黄海西部)温度锋面的完整形态为“N”形,东、西两部分平行岸线和等深线,中间部分跨越等深线。表层以下的黄海沿岸流和黄海暖流及分支是此锋面生成和维持的直接原因:南下沿岸流与北上的黄海暖流形成了锋面的东部部分,反气旋性回流的沿岸流与被沿岸流挟入南黄海西部的黄海暖流暖水及进入南黄海西部的黄海暖流分支形成了锋面的中部和西部部分。通过强烈的垂直混合,此锋面形态特征从表层以下传播到表层。沿岸流和暖流的强弱会影响此锋面的位置,锋面的形成会反过来影响上述流态。冬季风是维持相关环流和锋面结构的间接原因。 3,暖舌西移和双暖舌温度结构是冬季南黄海温度分布的主要特征,黄海暖流源区暖舌南北两侧形成的双锋面是南黄海锋面结构的主要特征,这两条锋面有时也可在西端连为一体,形成环绕黄海暖水舌前锋区的弧形锋面。南侧锋面大致沿长江浅滩边缘,北侧锋面大致呈东西走向,横跨黄海海槽入口,在此锋面的阻挡下,黄海暖舌无法沿海槽中央北上,在两锋面之间沿着黄海海槽西侧进入黄海。统计结果表明,北侧锋面的位置、强度变化,是驱使暖舌沿海槽西侧进入黄海、并控制其西移程度的主要因素。当北侧锋面偏南或强度大时,暖舌西移程度大,当两条锋面间隔距离大时,暖舌的西移程度弱,暖舌主体北侵的程度就越大,双暖舌结构越不明显。源区黄海暖流的东西向质量和热量输运,黄海内部的风应力等通过影响锋面的位置和强度而间接影响暖舌西移程度。黄海暖舌甚至黄海暖流的起源值得进一步探讨。 4,东海黑潮锋在台湾岛东北部和九州岛西南部的平均经向位置之间存在着反位相的年际变化规律。长期观测资料和数值试验结果都表明,进入东海的黑潮流量的改变能够导致黑潮锋面位置在两地反位相的变化:当黑潮流量增大时,黑潮在台湾岛东北部的向陆架入侵减小,锋面向南偏移,而同时黑潮在九州岛西南部的向陆架入侵增大,锋面向北偏移;冬季风应力在台湾岛东北部以东北风为主,在九州岛西南部以西北风为主。当风应力增大时,黑潮锋面在台湾岛东北部向西北偏移,在九州岛西南部向西南方向偏移。黑潮流轴位置的改变也可能是导致反位相变化的原因。位涡输运方程中的地形和斜压联合效应项以及风应力项(主要是Ekman输运)在两地的不同表现可能是控制这种变化的机制。