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1.
长江中下游流域是我国淡水贝类多样性最为集中的地区,然而由于人类活动的影响,淡水贝类已成为高度濒危的类群。为有效保护淡水贝类的多样性,我们于 2003 年 6 月-2005 年 5 月对长江中下游流域 13 个水体软体动物的多样性及分布进行了调查。共采集到软体动物 69 种(中国特有种 42 种),隶属于腹足类 9 科 14 属 29 种和瓣鳃类 5 科 17 属 40 种。其中,蚌科和田螺科是种类数最多的两个科,分别占总种类数的 50.7%和 14.5%。不同类型湖泊软体动物种类数的差别较大。通江湖泊所占种类数相对丰富,尤其是适应流水的种类,如河螺属、短沟蜷属及蚌科的种类。大型通江湖泊鄱阳湖和洞庭湖软体动物的种类数和特有种数分别 66 种和 40 种,分别占总种类数和总特有种数的 95.7%和 95.2%。阻隔水体所占种类数相对较少,种类数为 4-19种。与历史资料相比,长江中下游湖泊软体动物的种类数和特有种数均减少 50%左右,且多数种类的分布范围也明显缩小。造成贝类资源衰退的可能原因主要是江湖阻隔所引起的整个江湖复合系统栖息地和水文情势的改变,其他的人为活动如过度捕捞、围垦及废污水的过度排放等也可能是其中的重要原因。  相似文献   

2.
基于1950s以来的长江中下游湖泊鱼类调查数据,分析通江湖泊与阻隔湖泊的鱼类分类多样性差异,以及通江和阻隔湖泊鱼类分类多样性的时间序列变化,探讨江湖阻隔对鱼类多样性的影响。结果显示,阻隔湖泊鱼类物种数、平均分类差异指数(Δ+)和分类差异变异指数(Λ+)平均值分别为48.47±14.64、74.02±3.09和736.89±33.80;通江湖泊为76.22±14.40、78.31±0.98和697.31±25.53。阻隔湖泊物种数和Δ+值显著低于通江湖泊(P<0.001),而阻隔湖泊Λ+值显著高于通江湖泊(P=0.002),表明阻隔湖泊物种间亲缘关系更近,均匀度下降,即物种分类单元减少,且集中分布于某几个分类阶元,稳定性变差。典型通江与阻隔湖泊鱼类群落分类多样性的时间变化分析发现,两种类型湖泊的鱼类物种数和Δ+值均随时间推移整体呈现下降趋势,Λ+值整体呈现升高趋势;并且阻隔湖泊的Λ+值随阻隔时间增加而大幅上升,Δ+和Λ+...  相似文献   

3.
江西阳际峰自然保护区陆生贝类物种多样性   总被引:1,自引:0,他引:1  
2007年11月~2008年5月调查了江西阳际峰自然保护区陆生贝类资源,共采得陆生贝类47种(含2个未定种),隶属13科27属,其中16种为江西省陆生贝类新纪录种.区系分析表明,该保护区陆生贝类以东洋界成分为主,占种类总数的63.83%.其优势种为墙草真管螺和同型巴蜗牛.分析11个采集点生物多样性指数结果表明,Margalef丰富度指数(dMA)范围为0~6.2345;Shannon-Wiener多样性指数( H ′)范围为0~3.5676;Pielou均匀度指数( Jsw )范围为0~1.3610.环境越复杂,种类组成越丰富;物种分布越均匀的地区,陆生贝类多样性指数就越高.  相似文献   

4.
根据1992~1993年洪湖鱼类资源调查,结合1959年和1982年的历史资料,分析了洪湖鱼类物种多样性和群落结构多样性的变化。结果表明,洪湖鱼类从江湖阻隔初期的湖泊定居性鱼类为主、江湖洄游性鱼类和少数河海洄游性鱼类亦有一定的产量、大型和中型鱼类占较大比例,逐渐演变成以鲫占绝大多数的“众小”局面;鱼类群落的营养结构从草食性种类的比例高达23%~35%、肉食性种类比例波动于10%~20%之间,逐渐演变成以鲫为主的杂食性鱼类占绝大多数,草食性种类基本上从湖内消失;种类组成从阻隔前的推测应不下100种演变成50余种,且实际能在洪湖生息的只有30余种;多样性指数、均匀度指数均有不同程度的降低。  相似文献   

5.
采用典型调查与路线调查相结合的方法,对贵州乌江东风水库库区消落带苔藓植物区系的物种组成、生活型、分布区类型和丰富性进行了调查和分析.结果表明:该区域共有苔藓植物18科58属101种,其中,藓类植物有16科56属99种,苔类植物有2科2属2种;优势科为灰藓科(Hypnaceae)、青藓科(Brachytheciaceae)和丛藓科(Pottiaceae),优势属为青藓属(Brahchythecium B.S.G.)、真藓属(Bryum Hedw.)和小曲尾藓属〔Dicranella(Müll.Hal.)Schimp.〕;单属科和单种属所占比例均较高,分别占该区域苔藓植物总科数和总属数的500%和638%.该区域分布的苔藓植物生活型可分为交织型、丛集型、垫状和平铺型4类,以丛集型种数最多(48种),占该区域苔藓植物总种数的475%.该区域分布的苔藓植物可划分为12个分布区类型,其中,温带成分种类最多,所占比例为815%;热带成分所占比例仅为185%;中国特有种所占比例也较高,为207%.该区域苔藓植物的丰富性综合系数(Si)为-03608,低于相邻的六冲河下游流域.综合分析结果表明:该区域的苔藓植物多样性较为丰富,多数种类具有较强的抗逆性,且丛集型苔藓种类最多,与库区消落带的特殊生境相适应;地理成分以东亚成分和北温带成分为主,总体属温带性质,且中国特有种较多,反映出该区域苔藓植物区系的特殊性和复杂性.  相似文献   

6.
江西井冈山自然保护区陆生贝类多样性   总被引:1,自引:0,他引:1       下载免费PDF全文
2011年4~8月调查了江西井冈山自然保护区陆生贝类资源,共采得陆生贝类67种和亚种(含9个未定种),隶属4目19科31属,其中有1新种,即龙潭弯螺(Sinoennea sp.nov.)(另文报道);14种为江西省陆生贝类新纪录种;优势种为长柱倍唇螺(Diplommatina paxillus longipalatalis)、细锥倍唇螺(D.apicina)、灰尖巴蜗牛(Bradybaena ravida ravida)、双线巨蓬蛞蝓(Meghimatium bilineatum)。区系组成以东洋界成分为主,占种类总数的74.14%。阔叶林、灌木丛和农田生境陆生贝类种类较丰富,竹林和苔藓生境种类较少。根据调查数据,分别计算井冈山自然保护区5种不同生境类型中陆生贝类群落的多样性、丰富度和均匀度,结果表明,灌木丛生境陆生贝类的丰富度指数和多样性指数均最高,苔藓生境的均匀度指数最高。与邻近自然保护区比较,井冈山自然保护区陆生贝类物种较丰富,且与江西齐云山陆生贝类物种相似系数较高,与广东南岭物种相似系数较低。  相似文献   

7.
本文采用踏查法对罗霄山脉地区大型真菌资源进行了为期5年的调查, 共采集标本5,100多号。结合形态学与分子生物学方法, 鉴定出大型真菌2门7纲20目72科218属672种, 其中幕阜山脉115种、九岭山脉168种、武功山脉77种、万洋山脉220种、诸广山脉193种; 新增罗霄山脉新记录属37个、新记录种514种。对罗霄山脉大型真菌物种组成分析表明, 含10种以上的优势科有18科, 其物种数占物种总数的73.36%, 为多孔菌科、蘑菇科、粉褶蕈科等; 含5种以上的优势属有34属, 其物种数占物种总数的55.36%, 包括粉褶蕈属(Entoloma)鹅膏属(Amanita)小皮伞属(Marasmius)等; 在该山脉发现中国特有属2个, 中国特有种46个。大型真菌资源利用价值评估表明, 罗霄山脉有食用菌133种、药用菌136种、毒菌87种, 部分种类具有良好的应用前景。本研究为该地区大型真菌资源的保护、利用和管理提供了较重要的科学依据。  相似文献   

8.
2008年7月至2011年11月间先后4次调查了江西婺源森林鸟类自然保护区陆生贝类资源,共采得陆生贝类57种(亚种)(含3个未定种),隶属16科28属,其中1种为江西省新纪录种,优势种为长柱倍唇螺Diplommatina paxillus longipalatalis和细纹灰尖巴蜗牛Bradybaena ravida redfieldi。区系组成以东洋界成分为主,占种类总数的64.9%。分析11个采集点生物多样性指数结果表明,Margalef丰富度指数(dMA)范围为0.423~5.501;Shannon-Wiener多样性指数(H')范围为0.047~2.333;Pielou均匀度指数(Jsw)范围为0.030~0.438。与其他自然保护区相比较,婺源森林鸟类自然保护区陆生贝类物种较丰富,与阳际峰国家级自然保护区物种相似系数较高,与甘肃白水江国家级自然保护区物种相似系数较低,陆生贝类物种多样性有明显区域性特征。  相似文献   

9.
破罡湖通江前后湖滨带夏季水生植物对比研究   总被引:2,自引:0,他引:2  
对破罡湖通江前后相隔一年的湖滨带夏季水生植物种类组成及生物量进行的测量及对比研究表明:(1)通江一年并未造成该湖水生植物物种组成变化,该湖仍然延续了以往11属12种的种群格局,且挺水植物群落几乎不受影响;(2)通江引起了沉水植物群落优势种的变化,马来眼子菜、穗花狐尾藻和菹草出现较大幅度的衰退,玻璃藻赢得了竞争优势;(3)江湖对流打散了浮萍+紫萍群落,金鱼藻生物量得以增加;(4)通江一年后,该湖平均生物量更为接近同类湖泊最佳保有生物量。  相似文献   

10.
南洞庭湖沅江段为我国重要通江湖泊洞庭湖的重要组成部分,为了解其鱼类资源现状,于2013年8月—2015年12月期间对南洞庭湖沅江段鱼类资源进行调查。共采集鱼类标本12 962尾,经鉴定共计66种,隶属于7目13科44属,鲤形目占调查区域鱼类种类的69.70%,鲇形目和鲈形目次之。区系分布主体以地理位置所处的华东区为主,兼有华南区、华西区、北方区和宁蒙区的区系组成部分,华东区特有种占总种数的24.24%。栖息习性以湖泊定居型为主,占总种数的80.30%;食性以杂食性为主;栖息水层以底层为主;鱼类多样性指数(H′)为2.32,均匀度指数(J)为0.55,相较洞庭湖其他湖区处中等水平。调查结果相较历史调查记录出现种类数大幅减少、经济鱼类小型化、洄游型鱼类减少的现象,呈现衰退趋势。  相似文献   

11.
Long-lived lakes are often sites of spectacular endemic radiations. During the Oligocene to recent history of the Paratethys, large, long-lived (more than a million years) lakes with endemic faunas formed three times, in three different basins: the first in the Pannonian basin, the second in the Euxinian (Black Sea) basin, and the third in the Caspian basin. Because the Euxinian lake inherited much of the fauna of Lake Pannon, the three lakes together hosted two endemic radiations of molluscs. The most long-lived lake in the region was Lake Pannon, which persisted approximately seven million years from the late Middle Miocene to the Early Pliocene. Lake Pannon was formed by isolation from the sea. Changes in hydrological regime and/or water chemistry in addition to the relative lowstand which accompanied (or caused) the isolation almost completely exterminated the restricted marine fauna of the basin. A few highly euryhaline and marginal marine cardiids, dreissenids, and hydrobiids survived this environmental change. As in other fossil and extant long-lived lakes, the originally low-diversity fauna radiated into a high number of related endemic species (‘species flocks’) and genera in the expanding and ecologically vacated lake. Many originally freshwater taxa (unionids, sphaeriids, viviparids, valvatids, melanopsids, lymnaeids, planorbids) entered the lake as well, and some of them also gave rise to endemic clades. Evolution in both relict and freshwater immigrant groups led to the appearance of highly unusual shell shapes. Many lineages exhibit gradual morphological changes over one to several million years. More than 900 endemic mollusc species have been described from Lake Pannon, although this number includes junior synonyms, invalid species names, and highly similar chronospecies. Applying a conservative taxonomy, all these species belong to four bivalve and eight gastropod families. The high degree of endemism, however, is reflected by proposals of some authors to establish as many as five new families based on Lake Pannon endemics.  相似文献   

12.
长江流域兽类物种多样性的分布格局   总被引:1,自引:0,他引:1  
共记录了长江流域内兽类280种,隶属于11目36科135属,特有种和受威胁物种分别有14种和154种。根据兽类分布特点,依据山系和水系将长江流域分为19个区域,除了江源区外,物种丰富度、G-F多样性指数和特有种比例,从上游到下游区域总体趋势是随海拔降低逐渐降低,形成以四川盆地和沅江为分界线的3个数量级;利用Jaccard物种相似性系数对长江流域内19个区域进行聚类分析,发现整个流域分成4部分:江源区;横断山区、川西高原、云南高原、四川盆地和秦巴山区;贵州高原、江南丘陵、鄱阳湖平原和长江三角洲;淮阳山地、两湖平原和长江下游平原,基本反映了流域内自然地理环境及我国大陆地势三级台阶变化的特点。  相似文献   

13.
Ciliate community composition was investigated in four subtropical eutrophic lakes with cyanobacterial blooms in three seasons during 2009–2010 using the quantitative protargol staining approach. Among the four lakes, Lake Taihu and Chaohu are situated in the mid-lower Yangtze Plain near sea level, and Lake Dianchi and Xingyunhu are located on the Yunnan–Kweichow Plateau. A total of 102 ciliate species, representing 15 orders and 66 genera, were studied. Ciliate communities in Lake Taihu and Chaohu were characterized by abundant algivorous and mixotrophic oligotrichs and prostomatids, while Lake Dianchi and Xingyunhu ciliate communities were primarily characterized by voracious bacterivorous scuticociliates and peritrichids. Cluster analysis based on the transformed square root of ciliate abundance showed that samples from Lake Taihu and Chaohu composed one group whereas samples from Lake Dianchi and Xingyunhu composed another group in each season. Our results indicated that all dominant ciliate species are ubiquitous and that species dominance is regulated by different factors in different subtropical eutrophic lakes.  相似文献   

14.
Systematic review of the land snails of the Pitcairn Islands   总被引:1,自引:0,他引:1  
The land snails (and semi-terrestrial molluscs) of the four islands that comprise the Pitcairn group are reviewed and the indigenous species illustrated. The strictly terrestrial molluscan faunas from the two atolls (Oeno and Ducie) are poor, like many other atolls in the Pacific. Each supports less than six species with wide geographical ranges. In contrast, the terrestrial molluscan fauna from Henderson Island, an uplifted atoll, is more diverse with at least 16 species belonging to seven families. Over half these taxa appear to be endemic, at least at the level of sub-species. Two species of semi-terrestrial molluscs have also been found on Henderson. Analyses of archaeological deposits in caves near the North Beach have revealed that at least a further six species of land snail formerly occurred on Henderson. The volcanic island of Pitcairn, the only island in the group still inhabited, supports the greatest number of terrestrial molluscs. Twenty-six species of land snail (and one semi-terrestrial pulmonate) were found living there during the recent expedition and a further three taxa were recognized amongst museum material. At least seven of these species are thought to be recent adventives and a further three are likely to have been prehistoric introductions. One Henderson (Georissa hendersoni) and three Pitcairn endemics (Pacificella filica, Sinployea pitcaimensis and Diastole tenuistriata) are formally described as new species. Some of the Pitcairn endemics occur in very restricted areas (less than a hectare) and it is important that measures should be taken to prevent the spread of invasive plants, such as rose-apple, that would threaten their survival.  相似文献   

15.
段菲  李晟 《生物多样性》2020,28(12):1459-774
黄河流域幅员辽阔, 多样的地理气候、植被类型及人类活动塑造了多样化的生物多样性格局。本研究以IUCN与国际鸟盟发布的鸟类分布图层为基础, 同时收集了黄河流域2009-2019年的鸟类实地观测记录, 包括观鸟记录、GBIF数据库、红外相机监测及其他实地调查的鸟类数据, 共得到35,026条鸟类实地观测有效记录。汇总结果显示, 黄河流域记录有鸟类物种662种, 占中国鸟类物种总数的45.81%。这些鸟类分属于23目83科, 其中雀形目物种数最多(384种, 占本目全国鸟种总数的46.83%), 其次为鸻形目(67种, 占50.00%)和雁形目(39种, 占72.22%)。黄河流域受威胁鸟类共计121种, 其中有37种和52种分别在IUCN红色名录和《中国脊椎动物红色名录》中被列为受威胁物种(即评估级别为极危、濒危或易危), 22种和73种被分别列为国家I级和II级重点保护野生动物。这些受威胁鸟种多为地栖性、体型大、营养级高或具有长距离迁徙习性的物种。黄河流域鸟类整体物种多样性由南向北递减, 以黄河上中游四川、甘肃、陕西的高原与山地内鸟种最为丰富, 而受威胁鸟类物种多样性热点区则在黄河中下游, 下游黄河三角洲及邻近平原区为受威胁鸟类最主要集中分布区。黄河流域内48个国家级自然保护区共覆盖鸟种数504种(占黄河流域鸟类总种数的76.13%), 其中受威胁鸟种92种(占黄河流域受威胁鸟种数的76.03%)。区域内国家级自然保护区大多分布在黄河上游, 对黄河下游的受威胁物种覆盖程度较低, 保护空缺较严重。对此, 我们建议着重加强中下游自然保护区建设与能力提升, 增加对中下游受威胁鸟种的保护力度, 在保护策略上应当积极探索高强度土地利用下的多样化保护机制。  相似文献   

16.
The morphologically remarkable endemic fauna within ancient lakes has received much attention in the literature. More inconspicuous taxa, however, often lack detailed molecular and morphometrical examination, although their proportion of the endemic fauna of an ancient lake must not be underestimated. Consequently, a better understanding of evolutionary patterns and processes within these lakes requires more knowledge about the often-neglected inconspicuous taxa. In the present study, we focus on the notoriously cryptic pea clam genus Pisidium (Bivalvia: Sphaeriidae). Though the genus is widely distributed, most endemic species are reported only from ancient lakes, including the European ancient sister lake system of Ohrid and Prespa on the Balkan Peninsula. Here we test for the first time hypotheses on the evolution of the endemic pea clams in this European biodiversity hotspot by molecular means. Combining a broad 16S phylogeny (comprising most European pea clam species), network analyses and morphometrical analyses, we found interesting biogeographical patterns and provide evidence for cryptic species in both lakes. Furthermore, we confirmed the proposed sister-species relationship of the endemics P. edlaueri in Lake Ohrid and P. maasseni in Lake Prespa, and we suggest scenarios of the endemic pea clam evolution within both lakes. The patterns of speciation found in the genus Pisidium are compared to patterns in morphologically distinct molluscan groups in lakes Ohrid und Prespa.  相似文献   

17.
The recent expedition has doubled the number of marine molluscs known from the Pitcairn Islands. Over 80 taxa are recorded from Ducie and Pitcairn (both still poorly known), 240 from Oeno and 320 from Henderson. A total exceeding 400 taxa is now known from the group as a whole. Most of this increase results from a vastly improved knowledge of the small taxa that had been neglected in earlier surveys. Important faunal differences exist between the four islands in the group which are related to the different character of each island. These totals still underestimate the true diversities, but they provide data that are comparable in quality to those from adjacent regions. In this context the molluscan fauna from the Pitcairn Islands is seen to be impoverished when compared to those from islands further west. Most of the fauna is composed of widespread Indo-West Pacific species, but there are several taxa that have more restricted ranges centred on S.E. Polynesia. A few, including some undescribed taxa discovered on the expedition, appear to be endemic. Significantly, many of these are characterized by non-planktotrophic larval development. Comparison of the modern fauna from Henderson with the fossil fauna from the Pleistocene reef on its plateau reveals important differences. About 25% of the fossil molluscs are currently unknown from the group and about 5% appear to be undescribed. These high rates of turnover demonstrate that the faunas are temporally unstable.  相似文献   

18.
Monthly samples were taken in the River Tees below Cow Green dam from four sites differing in flow conditions, by means of trays containing stones from the river, which were immersed for a period of 1 month. Information on the distribution, abundance and biomass of the benthos of the River Tees is given with additional data on the life-histories of some of the more common species, during the period May 1971 to May 1972. Of the seventy-two taxa found, fourteen made up 95% of the total numbers. Hydra, Polycentropodidae, and the molluscs Limnaea peregra and Ancylus fluviatilis were the most abundant animals in the slower-flowing water (10–26 cm s?1) and Simuliidae, Orthocladiinae, and Baetis rhodani dominate the riffle (50–75 cm s?1) fauna numerically. Some organisms, Nais spp., Caenis rivulorum and Baetis scambus favoured intermediate flows of 20–60 cm s?1. The slowest-flowing water contained the largest number of taxa and the site with the fastest flow supported the least. A mean monthly weight per square metre of 14·56 g (95% limits from 7 to 31) was calculated using data from all four sites. The frequency distribution of nymphal size-classes is given for B. scambus, C. rivulorum, Ephemerella ignita, and Brachycentrus subnubilus, and the association of certain nymphal size-classes with a particular site is analysed. The composition and distribution of the fauna is discussed. It is suggested that the relative richness of the fauna in terms of biomass is attributable to the organic enrichment of the river following the building of the Cow Green dam. The regulation of the flow has allowed the dense growth of algae and mosses, and the development of large molluscan populations, and the reservoir itself provides a rich source of food, particularly zooplankton and phytoplankton, for the river benthos.  相似文献   

19.
Results of the study of 11 lakes situated in the mountainous part of the Amur River basin are reported. Six fish species, namely, blunt-snouted lenok Brachymystax tumensis, Baikal-Lena grayling Thymallus baicalolenensis, Siberian stone loach Barbatula toni, Lagowski’s minnow Rhynchocypris lagowskii, Czekanowski’s minnow Rh. czekanowskii, and Amur sculpin Cottus szanaga, were found in five lakes. Four species were found in one lake (Lake Pereval’noe, basin of the Amgun’ River), and two species were found in each of the remaining lakes. Lenok and Amur sculpin were the most common species. The fauna of Lake Okonon (basin of the river Zeya) was the most specific and did not have analogs among the lake faunas; Czekanowski’s minnow and Baikal black grayling were found in this lake. The lenok ecotype that formed in the mountain lakes differed from the river lenok in some regards. The potential pathways of formation and protection of mountain lake ichthyocenoses of the Amur basin are discussed.  相似文献   

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