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91.
湖北浮桥河水库底栖动物的群落结构及生物多样性   总被引:9,自引:3,他引:6  
1997年 4月至 1998年 1月 ,在浮桥河水库 14个采样点调查底栖动物 ,共获 4 7种 .其优势种类为霍甫水丝蚓 (Limnodrilushoffmeisteri)、中国长足摇蚊 (Tanypuschinensis)、前突摇蚊属 (Procladiussp .)和摇蚊属 (Chironomussp .) .水库底栖动物的Shannon指数和Margalef指数偏低 ,上游的指数值最高 .从种类相似性来看 ,底栖动物的季节变化不明显 ;在水平分布上 ,上游与库汊的种类相似性最低 ,库汊与下游的种类相似性最高 .浮桥河水库底栖动物的平均密度为5 2 9.1ind/m2 ,平均生物量为 35 34.1mg/m2 ,均以水生昆虫占优 ,其时空变化主要受水生昆虫控制 .能量估算法估算出浮桥河水库底栖动物的渔产潜力为 1.5× 10 4 kg/a .  相似文献   
92.
春季禁渔期间长江下游鱼虾蟹类物种多样性变动(2001-2004年)   总被引:19,自引:3,他引:16  
长江春禁期4-6月间,下游江段渔获中出现鱼、虾、蟹共12目、30科、81种.安徽、江苏江段年间物种多样性指数明显上升并趋于稳定,其中Shannon—Wiener(H’与H”)在1.593—2.563范围内呈上升并趋于稳定、Margalef在0.866—2.755范围内呈明显上升、Pielou、Simpson和McNaughton指数在窄幅波动中趋于稳定,波动范围分别为0.717—0.827;0.120—0.269;0.365—0.616.河口区多样性指数正处于波动中,Simpson和McNaughton指数分别从0.195升至0.315;从0.534升至0.758,并有继续上升的趋势.各江段年间捕捞证发放数与ShannonH’的回归分析表明两者呈负相关线型关系.  相似文献   
93.
水工程建设对长江流域鱼类生物多样性的影响及其对策   总被引:16,自引:2,他引:14  
黄亮 《湖泊科学》2006,18(5):553-556
长江流域鱼类种类丰富、资源量大、特有性高、经济种类多,其生物多样性具有重要的生态价值、经济价值和科学价值.流域内鱼类生物多样性由于面临河流梯级开发引起的洄游阻隔、生境破碎和水文情势等改变的严重威胁,种群下降趋势明显.为保护长江流域鱼类生物多样性,有必要更新水工程规划理念和设计技术,修建鱼道等必要过鱼设施,进行水库生态调度,建立鱼类自然保护区和建立生态补偿机制等.  相似文献   
94.
罗海  李杰  邹亚菲  徐会明 《地学前缘》2020,27(6):289-299
湖泊是全球生态系统的重要组成部分。尽管湖泊初级生产力的生物多样性在湖泊生态系统中发挥着非常重要的作用,但对其如何在千年时间尺度上对气候变化做出响应却知之甚少,而千年时间尺度与预测未来变化最为相关。本文以云南云龙天池湖泊为研究对象,以湖泊重要的初级生产力硅藻为研究手段,分析了末次冰消期期间硅藻生物多样性对千年尺度上气候变化的响应。云龙天池硅藻生物多样性表现为暖期高、冷期低。随着全球温度的快速变化,硅藻生物多样性亦对应的快速响应:在转暖时(Bolling/Allerod暖期)快速增加,在转冷时(Herinrich 1和Younger Dryas)快速降低。这些变化主要与温度变化驱动的湖泊环境条件的变化(比如冰封期长短、边岸带水生植被的变化等)有关。研究结果还表明,在末次冰消期期间,云龙天池湖泊硅藻生物多样性与千年尺度的气候变化同步,而且在长时间尺度上,气候变暖对高山湖泊生物多样性可能是有利的。  相似文献   
95.
The Mediterranean mussel Mytilus galloprovincialis is the most significant invasive alien marine species in South Africa and, although not normally found subtidally, has recently been observed colonising heads and stipes of the kelp species Ecklonia maxima in False Bay. We quantified this invasion and explored its ecological implications. Transects laid across kelp beds revealed that 10.34% of kelp individuals surveyed bore canopy mussels, with kelp heads (10.07%) being far more commonly infected than stipes (0.27%). Twenty kelp individuals with infected heads and 20 with infected stipes were separately collected for more-detailed examination. Wet mass of mussels on these kelp heads ranged from 2.5 to 2 462 g (median 86.4 g, interquartile range 14.8–353.8 g) and that of mussels on the stipes from 7.6 to 3 492 g (median 595.5 g, interquartile range 194.0–955.0 g). Mussel clumps consisted mostly of individuals <40 mm in length. Mussel clumps supported a rich biota of 80 invertebrate and 13 algal species. Larger clumps supported more epibiotic species, and those on stipes more species than those of comparable mass on kelp heads. The mussels and their associated epibiotic species negatively affected kelp buoyancy, but rarely enough to overcome natural buoyancy. Some kelp individuals that had been toppled by the weight of mussels and their epibiotic species, however, were encountered in situ. Implications of this invasion include large increases in animal biomass and species richness in the kelp canopy, plus reductions in kelp buoyancy and increased hydrodynamic drag on infected kelps, increasing their probability of being uprooted. Uprooted kelp individuals can raft long distances, potentially transporting both native and alien species to distant sites.  相似文献   
96.
Ecological quality is defined as the stability, adaptability and resilience of an ecosystem. Monitoring and assessing ecological quality are important bases for China's ecological civilization construction. The national key research and development program “Technologies and guidelines for monitoring ecological quality of terrestrial ecosystems in China”, launched in July 2017, includes plans to study the observation technologies and provide guidelines on the ecological in-situ observation, the regional biodiversity and ecosystem function monitoring and its applications, all of which contribute to national ecological quality assessment. A year after its implementation, some important progress has been achieved, such as building the indicator system for comprehensive monitoring of ecological quality and improvement of the methods, mass data transmission, infrared camera-based monitoring of biodiversity, multi-angle automatic spectral observation systems, and unmanned aerial vehicle (UAV) based desert monitoring. We have organized this special issue and attempted to introduce the monitoring techniques and assessment methods on ecological quality from different perspectives in order to further promote the development of ecology and its observation methods.  相似文献   
97.
Sawfishes are coastally distributed rays that grow to very large sizes. All five species are assessed as Endangered or Critically Endangered as a result of population declines caused mainly by entanglements in fishing gear and by habitat degradation. Three species occur in the western Indian Ocean, but their populations are believed to have declined drastically in many areas and little is known about their presence in Tanzania. Fisher interviews were conducted to provide an overview of the status of sawfishes in Tanzania and to highlight where conservation actions should be focused to conserve sawfishes nationally. In total, 386 interviews were conducted: 296 at 31 villages in four regions on Tanzania’s mainland, and 90 interviews at 12 villages in four regions of Pemba Island. Less than half (46%) of the fishers were familiar with sawfishes and could identify one from a photograph. A precipitous decline in sawfish abundance in Tanzania could be inferred from the age-related decline in local knowledge of their existence; all fishers aged between 70 and 80 years were familiar with sawfishes, whereas only 10% of fishers younger than age 20 had ever heard of them. A total of 29 sawfish records were compiled, comprising 16 rostra and 14 catches that occurred between 2002 and 2014 (one record included both a catch and a rostrum). All rostra examined were from the largetooth sawfish Pristis pristis. Since 2002, the sawfish catches occurred in three locations, all on the mainland coast: in the southern Mtwara region, in the vicinity of the Rufiji Delta, and at Bagamoyo on the Zanzibar Channel. Interview data and rostra evidence suggest that the Rufiji Delta may be a largetooth sawfish nursery area, and confirmation of this should be a priority.  相似文献   
98.
In a world facing rapid environmental changes, anticipating their impacts on biodiversity is of utmost relevance. Remotely-sensed Ecosystem Functional Attributes (EFAs) are promising predictors for Species Distribution Models (SDMs) by offering an early and integrative response of vegetation performance to environmental drivers. Species of high conservation concern would benefit the most from a better ability to anticipate changes in habitat suitability. Here we illustrate how yearly projections from SDMs based on EFAs could reveal short-term changes in potential habitat suitability, anticipating mid-term shifts predicted by climate-change-scenario models. We fitted two sets of SDMs for 41 plant species of conservation concern in the Iberian Peninsula: one calibrated with climate variables for baseline conditions and projected under two climate-change-scenarios (future conditions); and the other calibrated with EFAs for 2001 and projected annually from 2001 to 2013. Range shifts predicted by climate-based models for future conditions were compared to the 2001–2013 trends from EFAs-based models. Projections of EFAs-based models estimated changes (mostly contractions) in habitat suitability that anticipated, for the majority (up to 64%) of species, the mid-term shifts projected by traditional climate-change-scenario forecasting, and showed greater agreement with the business-as-usual scenario than with the sustainable-development one. This study shows how satellite-derived EFAs can be used as meaningful essential biodiversity variables in SDMs to provide early-warnings of range shifts and predictions of short-term fluctuations in suitable conditions for multiple species.  相似文献   
99.
The aim of this paper is to identify the general trend of changes and the basic requirements of the most important lagoon system of the Black Sea, on the basis of critical analysis of existing data. A more coherent set of data sampled after 1988 on the basis of some intensive and extensive study and research programmes, including the main trophic parameters and the most representative structural and functional features of this complex of ecotonal lakes, is comparatively analysed together with more fragmentary data previously existing. The structural and functional changes within this complex of lakes were analysed based on 31 most representative variables belonging to the main abiotic and biological compartments of the two main lakes, Razim and Sinoe: dissolved organic carbon, dissolved oxygen, trophic state index TSI, nutrient content and ratio, salinity, chlorophyll, phytoplankton, zooplankton, submerged macrophytes, zoobenthos, fish and birds. Two stages were distinguised in the main structural changes, including morphometric connections with the Danube River and the Black Sea and hydrochemistry and its effects on communities. These transitions were associated with two main driving forces, water desalinisation and rapid eutrophication, and with other two kinds of man-induced changes, local hydrotechnical buildings and long-distance variables operating over the entire Danube River watershed. The information support system for sustainable management of the Razim-Sinoe Lagoon Complex as a part of the Danube Delta Biosphere Reserve, integrating existing data from research programmes and an integrated monitoring system for new data is a final conclusion on further needs.  相似文献   
100.
冯喆  许学工  周建  高阳 《地理科学进展》2016,35(9):1100-1108
“土地分离和共享框架”是协调物质生产和生态保护、促进土地可持续利用的重要理论。本文梳理了“土地分离与共享框架”和生态系统服务间关联,剖析生态系统服务应用于该框架的理论基础,结合美国典型土地共享案例,分析了土地利用策略选择对粮食生产、生物多样性、直接和间接生态系统服务的影响,并探讨了该框架对中国生态系统工程的启示。结果表明:随着人类对土地功能认知的不断深入,“土地分离与共享框架”的拓展表现为从单一的粮食供给服务需求演进到粮食供给服务和其他生态系统服务的综合需求。当粮食供给服务与其他服务处于权衡状态时,在生态脆弱、恢复力差的地区,不同生态系统服务间多处于凸权衡关系,一般适宜采用分离策略;在生态系统稳定、恢复力强的地区,不同生态系统服务多处于凹权衡关系,一般适宜采用共享策略。结合美国典型土地共享案例发现,其土地利用实践中选择土地功能共享策略是比较适宜的;生态系统服务作为政策评估工具,可在策略选择和评估实施效果中发挥一定作用。研究结果可为可持续土地利用提供理论与方法支撑,并为中国制定土地利用策略提供参考。  相似文献   
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