Are the fish of the upper and lower Mekong interconnected？     

康斌  PERRETT Lisa  李运刚  何大明 《中国海洋湖沼学报》2009,27(2):400-407

The Mekong supports one of the richest inland fisheries in the world, with many of the fish migrating long distance to spawn. Little is known about the fisheries and migration strategies of the Upper Mekong whilst it is supposed that many fish species move between the Lower and Upper Mekong. Most likely, natural fish migration in the river has been altered by dam construction across the mainstream of the Upper Mekong. In this paper, the interconnectivity of fish species between different sections of the Mekong and negative impacts of dams on migratory fish are studied. Of the 162 fish species in the Upper Mekong and the 869 species in the Lower Mekong, 61 species are common. Results show that there is no significant difference at order level between the UM and LM. Similarity coefficients are used to evaluate interconnectivity at species, genus and family levels among four different sections of the Upper Mekong with each other and with the Lower Mekong as a whole. The highest similarity is found between the middle and lower reach of the Upper Mekong at species and genus levels and the middle and upper reach at family level. Of the eight cascade dams, Mengsong Dam in planning is considered as the biggest threat to migratory fish from the Lower Mekong and should be particularly concerned. Supported by National Natural Science Foundation of China (No. 40601096)  相似文献   

WISE EXPLOITATION OF NEWLY GROWING LAND RESOURCES——An Assessment on Land-use Change of Chongming Island Using GIS   总被引：2，自引：0，他引：2  

ZHAO Bin    LI Bo  MA Zhi-jun  CHEN Jia-kuan  NAKAGOSHI Nobukazu 《中国地理科学(英文版)》2003,(2)

1INTRODUCTIONThreewell-documentedmajorglobalchangesaffectinghumanbeingsareincreasingconcentrationofcarbondioxideintheatmosphere,alterationinthebiochemistryoftheglobalnitrogencycle,andon-goinglanduse/coverchange(LUCC)(VITOUSEK,1994).Forcen-turies,humanbeingshavebeenalteringtheearth'ssurfacetoproducetheirfoodandsheltersthroughagri-culturalactivities(REIDetal.,2000).Likeothercountries,Chinaisalsosubjecttolandtransformation,forinstance,abouthalfamillionhectaresofwetlandshavebeenreclaime…  相似文献   

秦皇岛七里海潟湖湿地非繁殖期鸟类多样性          下载免费PDF全文

戴宇飞  吴福星  赵丽媛  雷威  曾千慧  王先艳 《应用海洋学学报》2019,38(4):569-577

2016年9月至2017年4月,采用样线法和可变大小样方法相结合,对七里海潟湖湿地非繁殖期鸟类进行了调查研究。调查共记录到鸟类13目27科60种,其中雀形目鸟类10科14种,占物种总数量的23. 33%;非雀形目鸟类17科46种,占物种总数量的76. 67%。湿地水鸟数量占全部鸟类总数量的95. 11%,水鸟类群主要为鸥类、雁鸭类、鸻鹬类和鹭类。鸟类居留类型主要为旅鸟和夏候鸟,分别占物种总数量的35. 00%和33. 33%。鸟类区系方面,以古北界鸟类和广布种鸟类为主,分别占物种总数量的63. 33%和26. 67%。经统计,鸟类多样性指数、均匀度指数和丰富度指数的平均值分别是1. 86、0. 39和2. 31。七里海潟湖湿地位于东亚—澳大利西亚迁徙路线上,是重要的鸟类迁徙停歇地和觅食地,鸟类尤其是水鸟资源丰富,应当受到关注和保护。  相似文献   

GAP分析：保护生物多样性的地理学方法   总被引：4，自引：0，他引：4  

刘吉平  吕宪国  殷书柏 《地理科学进展》2005,24(1):41-51

GAP分析1988年由Burley首次提出并被Scott在夏威夷项目中首次应用。GAP分析（保护生物多样性的地理学方法）是快速概观生物多样性几种要素的分布和保护状态的一种方法,它集中在生物有机体更高层,基于生境保护和多物种保护的双重目的,已被证明是保护大尺度生物多样性行之有效的方法之一。目前GAP分析主要集中于陆地脊索动物门的研究,而对水生生境和其它动物门研究较少,同时对生物多样性的过程研究不足。本文在对GAP分析的内涵、产生、研究现状综述的基础上,分析GAP分析的优缺点和发展趋势,并对我国GAP分析进行研究。由于中国的GAP计划尚未进行,现阶段中国的GAP分析应首先集中在一些生物多样性典型地区或针对一些濒危和稀有物种进行研究,然后推广到其它地区或普通物种。  相似文献   

Challenges of forest governance in Madagascar     

WILLIAM J MCCONNELL  SEAN P SWEENEY 《The Geographical journal》2005,171(3):223-238

There has been a huge surge in interest in the preservation of Madagascar's forests in the past two decades, but despite the investment of hundreds of millions of dollars, the goal remains elusive. Recent legislation has given the government the authority to enter into contractual arrangements with communities for the management of the country's public forests, so it has become crucial to grapple with the significant challenges involved. This paper explores the enormity of the challenge of forest governance in Madagascar in an era of decentralization. By examining several forests in one part of the country, it reveals a dizzying range of forest types and forms of use and governance within a fairly small portion of the country. These examples make it apparent that the history of forest management in Madagascar constitutes a broad-ranging experiment with forest governance. Simply monitoring the dynamics of the forest canopy is a significant technical challenge. However, this pales in comparison to the difficulties inherent in explaining those dynamics and assessing the sustainability and equity of different management regimes. Of the forests considered in the study, those where the Malagasy state has partnered with international conservation and development organizations seem to stand out, both in terms of stabilized, or even growing, forest cover, as well as a balance of interests among users.  相似文献   

Environmental economics of the Khangchendzonga National Park in the Sikkim Himalaya, India   总被引：4，自引：0，他引：4  

Iyatta Maharana  S.C. Rai  E. Sharma 《GeoJournal》2000,50(4):329-337

A contingent valuation survey was conducted involving local community members, domestic and foreign visitors to estimate the environmental economics of the Khangchendzonga National Park and to elicit their willingness-to-pay (WTP) for its maintenance and conservation. Using a random survey, the average WTP was US$ 8.84 for foreign visitors per visit, followed by US$ 6.20 per household per year by local community members and US$ 1.91 per domestic visitor per visit for improvement in environmental conservation. The WTP was strongly influenced by age, education and income. The present study demonstrated that the contingent valuation method (CVM) is a promising approach, however it lacks inclusion of non-monetary contributions. The WTP for environmental management by the local communities was mostly in kind or time for services. The CVM can be a useful tool for decision-makers regarding investment and policy purposes for management of biodiversity hot spots and protected areas in developing countries. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Combination of ecoprofile and least-cost model for eco-network planning   总被引：1，自引：0，他引：1  

He Xiao  Yunhui Liu  Zhenrong Yu  Qian Zhang  Xin Zhang 《中国地理科学(英文版)》2014,24(1):113-125

The protecting requirements and functional connectivity of species in isolated habitat patches are crucial factors of eco-network planning.This study aimed to improve the method of eco-network planning for species conservation.Ecoprofiling was used to group the species by similar behavior types,namely,choice of ecosystem,area requirement,and short distance dispersal abilities.A least-cost model was used to simulate the optimal corridor location to maintain functional connectivity.A combination of ecoprofile and least-cost model was hired to develop an eco-network that promoted species conservation.A case study was also conducted in Bei-jing,China.In addition to the required ecosystem,habitat area is an important parameter for habitat extraction.Habitat area can remove noise habitat patches because of lacking area.Short-distance dispersal can be used to identify corridor requirements and avoid unneces-sary building requirements.Species with various dispersal abilities exhibit significant differences in terms of corridor length and loca-tion requirement.Habitat isolation is the main threat for weakly mobile species,and habitat loss is the major risk of mobile species pro-tection.Different species groups also exhibit distinct landscape pattern demands for an eco-network,and the eco-network planning based on specific species can not protect other species.We proposed that a combination of ecoprofile and least-cost model improved the efficiency of species conservation by eco-network planning.  相似文献   

Effects of grazing exclusion on plant productivity and soil carbon,nitrogen storage in alpine meadows in northern Tibet,China   总被引：4，自引：1，他引：3  

Dingpeng Xiong  Peili Shi  Yinliang Sun  Jianshuang Wu  Xianzhou Zhang 《中国地理科学(英文版)》2014,24(4):488-498

Grazing exclusion is widely adopted in restoring degraded alpine grasslands on the Qinghai-Tibetan Plateau. However, its effectiveness remains poorly understood. In this study, we investigated the effects of grazing exclusion on plant productivity, species diversity and soil organic carbon （SOC） and soil total nitrogen （STN） storage along a transect spanning from east to west of alpine meadows in northern Tibet, China. After six years of grazing exclusion, plant cover, aboveground biomass （AGB）, belowground biomass （BGB）, SOC and STN were increased, but species diversity indices declined. The enhancement of AGB and SOC caused by grazing exclusion was correlated positively with mean annual precipitation （MAP）. Grazing exclusion led to remarkable biomass increase of sedge species, especially Kobresia pygmaea, whereas decrease of biomass in forbs and no obvious change in grass, leguminous and noxious species. Root biomass was concentrated in the near surface layer （10 cm） after grazing exclusion. The effects of grazing exclusion on SOC storage were confined to shallow soil layer in sites with lower MAP. It is indicated that grazing exclusion is an effective measure to increase forage production and enhance soil carbon sequestration in the studied region. The effect is more efficient in sites with higher precipitation. However, the results revealed a tradeoff between vegetation restoration and ecological biodiversity. Therefore, carbon pools recover more quickly than plant biodiversity in the alpine meadows. We suggest that grazing exclusion should be combined with other measures to reconcile grassland restoration and biodiversitv conservation.  相似文献   

白令海和楚科奇海表层沉积物中多环芳烃降解微生物多样性   总被引：4，自引：0，他引：4  

张荣秋  董纯明  盛华芳  白秀花  矫立萍  刘金禄  汪卫国  周宏伟  邵宗泽 《海洋学报》2014,36(4):52-61

为了研究白令海(海盆及陆架)至楚科奇海陆架表层沉积物中多环芳烃(PAHs)降解菌的多样性,并获得新的PAHs降解菌资源。在GC-MS分析沉积物中PAHs种类和含量的基础上,以萘、菲和芘的混合物为唯一碳源和能源对表层沉积物样品进行富集,通过平板分离鉴定可培养菌株,并验证其降解能力;同时利用变性梯度凝胶电泳(DGGE)和Illumina高通量测序技术分析降解菌群结构。GC-MS测定结果表明,14个表层沉积物中PAHs总干质量介于32.99~276.97ng/g。富集菌群中共分离获得51株可培养细菌,平板纯培养、PCR-DGGE及Illumina测序结果均表明,菌群中优势的降解菌是γ-proteobacteria的Marinobacter,Pseudoalteromonas,Pseudomonas和Actinobacteria门的Dietzia菌。此外,Illumina测序结果还表明14个降解菌群在菌群结构组成上,可分为海盆区和陆架区两种类群;同时检测到一些低丰度的海洋专属PAHs降解菌,如Cycloclasticus,Alteromonas和Neptunomonas等。本文结果将加深对白令海及楚科奇海表层沉积物中PAHs降解菌资源与生物多样性的认识。  相似文献   

Biodiversity and community structural characteristics of macrobenthos in the Chukchi Sea   总被引：1，自引：1，他引：0  

WANG Jianjun  LIN Heshan  HE Xuebao  LIN Junhui  HUANG Yaqin  LI Rongguan  ZHENG Chengxing  ZHENG Fengwu  JIANG Jinxiang 《海洋学报(英文版)》2014,33(6):82-89

Field sampling of the macrobenthos from 23 stations in the Chukchi Sea was conducted during the 4th CHINARE(Chinese National Arctic Research Expeditions, July–August, 2010). We identified a total of 140 species of macrozoobenthos belonging to nine phyla, which were dominated by polychaetes(66), crustaceans(30), and mollusks(25), followed by echinoderms(9) and others(ten others, including four cnidarians, one oligochaete, one sipuncula, one priapulida, two bryozoans, and one urochordata). The dominant species were Aphelochaeta pacifica, Heteromastus filiformis, Nephtys ciliata, Nephtys caeca, Scoletoma fragilis, Golfingia margaritacea, Nuculana pernula, Macoma calcarea, Ennucula tenuis, Macoma inquinata, Musculus discors, Echinarachnius parma, and Ophiura sarsii, so there were more cold-eurythermal boreal immigrants than truly Arctic species(endemics). The average density and biomass(mean ± SD across all stations) of the total macrozoobenthos were(916 ± 907) ind/m2 and(902.9 ± 1 227.7) g/m2(wet weight), respectively. Relatively high density and biomass were observed in the samples from the northeastern and southern Chukchi Sea. The spatial variation of benthic communities in the study sea area was relatively large; this spatial heterogeneity has led to high diversity and a patchy distribution pattern in the community structure. Compared to the 1st CHINARE( July–August, 1999), this investigation revealed different degrees of decreases in the average taxa numbers and the average density, abundance, and biodiversity in the area over the recent decade, which might be associated with global warming, human activities, and sea ice variations.  相似文献