淡水贝类生物多样性保育

生物多样性是地球上生命经过几十亿年发展进化的结果,是人类赖以生存的最重要的物质基础。然而,随着世界人口的迅猛增加及人类经济活动的不断加剧,物种灭绝的速度不断加快,现在地球上物种灭绝速度达到自然灭绝速度的近1000倍,无法再现的基因、物种正以人类历史上前所未有的速度消失。全球生物多样性的研究与保护正成为当今世界所关注的热点问题。     

中国淡水藻类生物多样性研究进展

概述了中国淡水灌类物种多样性和遗传多样性研究的现状,讨论了生境的多样性和及其与藻类物种多样性的关系。同时探讨了藻类多样性所面临的问题,提出了关于保护和利用措施方面的建议。     

生物多样性保护与自然保护区

1 自然保护区是生物多样性保护的重要基地 生物多样性是人类社会赖以生存和发展的基础。生物多样性保护已是当今人们最为关注的热点问题,越来越多的人认识到,生物资源是有限度的,发展依赖于保护生物多样性。破坏生物多样性的因素错综复杂,保护生物多样性需要社会有关方面采取广泛对策。实践表明,为保护物     

黄河兰州段鱼类多样性与保护

兰州市是黄河唯一穿城而过的省会城市, 是黄河流域综合治理与高质量发展的重要区域, 了解其鱼类多样性现状及变化趋势对黄河流域水生态保护尤为重要。本文于2020年7-10月对黄河干流兰州段及其4条支流(庄浪河、大通河、湟水河和宛川河)开展了鱼类多样性、分布及影响因素调查, 以Shannon-Wiener多样性指数、Pielou均匀度指数、Simpson优势度指数、Cody和Routledge指数、Bray-Curtis相异性系数对黄河兰州段5条河流鱼类群落进行评估, 同时通过相对多度(relative abundance, RA)判定优势种, 利用非度量多维标度排序(non-metric multidimensional scaling, NMDS)展示物种空间分布格局。本次调查获得鱼类20种, 隶属于4目6科15属。其中, 国家II级重点保护野生动物1种, 受威胁鱼类4种, 中国特有鱼类7种, 黄河特有鱼类4种。区系组成属青藏高原区高原西北亚区, 其中鲤形目种类占绝对优势, 优势种为东方高原鳅(Triplophysa orientalis)、粗壮高原鳅(T. robusta)、鲫(Carassius auratus)和麦穗鱼(Pseudorasbora parva)。庄浪河和黄河干流的α多样性较高。β多样性分析结果表明, 黄河干流与庄浪河、大通河、湟水河和宛川河间的鱼类物种明显不相似; 大通河与湟水河之间以及黄河干流与宛川河之间的鱼类物种组成相似性较高。NMDS分析表明, 黄河兰州段鱼类被划分为地理空间上相近的4个地理群。水利设施建设、外来物种和水体污染可能影响了黄河兰州段鱼类多样性和分布。本研究为黄河兰州段鱼类多样性保护和科学管理以及黄河流域生态保护和高质量发展提供了基础调查数据。     

海南岛淡水蟹类分布格局与多样性保护

热带岛屿生物多样性是全球生物多样性保护研究的热点之一。海南岛是中国面积最大的热带岛屿, 丰富独特的淡水蟹类是维持岛内淡水生态系统功能完整性的关键类群。本文通过多年野外调查, 综合历史及最新文献资料, 对海南岛淡水蟹类物种多样性及其现状进行调查和评估, 并对淡水蟹类物种多样性保护现状进行了分析讨论。研究发现, 海南岛淡水蟹类物种多样性分布中心位于中南部山地, 主要集中于中部的霸王岭、鹦哥岭和猕猴岭, 南部的五指山和吊罗山, 以及西南部的尖峰岭一带。其物种多样性整体上呈现中南部山地高、平原台地低的特点。根据《IUCN物种红色名录濒危等级和标准》对海南岛淡水蟹类物种现状的评估结果显示, 全岛受威胁淡水蟹类物种的占比为16.7%。基于分布区预测, 以海南热带雨林国家公园为主体的保护地对淡水蟹类潜在适宜分布区的覆盖度明显优于此前碎片化的各级保护区。本文研究结果显示, 海南岛淡水蟹类的总体生存状况良好, 但一部分山地或平原种类处于受胁状态。国家公园体制的建立有望为岛内淡水蟹类物种多样性保护提供前所未有的机遇。基于物种多样性分布格局开展淡水蟹类等淡水生物多样性监测, 有助于促进海南岛淡水生态系统完整性的长效保护与可持续发展。     

《长江重要鱼类生物多样性和保护研究》介绍

《长江重要鱼类生物多样性和保护研究》（上海科学技术出版社2001年12月出版）是我国首卷系统阐述有关长江重要经济鱼类生物多样性及其面临问题和保护对策的专著。该书共分 13章,约 20万字。作者从长江生物多样性入手,渐次深入到主要经济和珍稀鱼类的遗传变异,逐层讨论了就地保护、异地保护和开发利用等问题。该书从群体、个体、细胞及分子水平,以及渔业生物学、群体遗传学和保护生物学相结合,深入介绍和探讨了长江重要经济鱼类的遗传多样性与保护利用,具有较高的学术价值和实用参考价值。     

长江生物多样性变迁—鱼类

<正>长江流域内共记录鱼类378种,其中纯淡水鱼类339种,占我国淡水鱼总数的1/3。长江中还栖息着149种珍稀的特有鱼类。长江流域渔产量约占全国淡水渔业产量的2/3。长江流域自然资源捕捞量1954年曾达到45万吨,到八十年代初下降到20余万吨,近几年捕捞量维持在6万吨左右;六十年代长江主要经济鱼类的产量约占总产量的28%,     

自然杂交与生物多样性保护

物种之间的杂交事件在自然界中时常发生,虽然大部分自然杂交会成为进化的盲端而被淘汰,但仍有一部分自然杂交在物种形成过程中起到很重要的作用。随着对自然杂交认识的深入,人们对其是否具有保护价值存在着较大的争议。本文从遗传多样性、物种多样性和生态系统多样性三个方面综述了自然杂交在物种进化和生态系统中的作用,认为并不是所有杂交都存在着物种逆转的危险,一些杂交事件可以增加生物多样性,提高物种的环境适应性。同时,我们结合近年来自然杂交的研究案例,提出自然杂交的保护原则:对父母本没有威胁,同时有助于提高生物多样性和环境适应性的自然杂交应该予以保护。希望该建议为国家制定物种保护法律法规和编制红色名录提供参考。     

中国古籍与生物多样性保护

本文提出一种借助古代文献恢复自然生态系统的方法,而中国古籍在这方面可以发挥巨大的作用。生物多样性保护的技术性关键在于找到合适的生态系统,而自然生态系统就是其中之一。中国古籍,特别是中国医书、中国农书和中国方志的有关记载为寻找这种生态系统提供了大量的信息。因此我们可以参考中国古籍,使现存的复合生态系统逐步地接近自然生态系统,从而达到生物多样性保护的目的。     

景观生态学与生物多样性保护

景观生态学的发展为生物多样性保护提供了新理论,方法和技术手段,从景观多样性与遗传多样性,物种多样性,生态系统多样性各层次生物多样性之间的相互关系及生物多样性保护的景观规划等方面评述近年来景观生态学应用于生物多样性保护的主要内容及研究进展,阐述了生物多样性动态及反馈,生物多样性保护的地理途径（ＧＡＰ分析）,景观生态安全格局,区域和大陆尺度的生态网络等一些新的概念和方法。     

Identifying priority sites for the conservation of freshwater fish biodiversity in a Mediterranean basin with a high degree of threatened endemics

The Guadiana River basin’s freshwater fish species richness, endemicity and threatened status (92% of native species are threatened) highlight the need for a large-scale study to identify priority areas for their conservation. One of the most common problems in conservation planning is the assessment of a site’s relative value for the conservation of regional biodiversity. Here we used a two-tiered approach, which integrates an assessment of biodiversity loss and the evaluation of conservation value through site-specific measures. These measures based on the reference condition approach introduce the ability to make objective comparisons throughout the Guadiana River basin, thus avoiding a priori target areas. We identified a set of biodiversity priority areas of special conservation significance—which contain rare taxa as well as intact fish communities—because of their outstanding contribution to the basin’s biodiversity. The inclusion of complete sub-basins in these priority areas might guarantee an optimal solution in terms of spatial aggregation and connectivity. However, the high spatial fragmentation to which the Guadiana River basin is submitted due to river regulation highlights the necessity of a systematic approach to evaluate the capability of the identified priority areas to maintain the Guadiana’s freshwater fish biodiversity. Handling editor: R. H. Norris     

Dragonfly Assemblages in Arid Tropical Environments: A Case Study from Western Namibia

Dragonflies have been proposed as indicators for the ecosystem health of freshwater wetlands. For their useful functioning as indicators it is, however, necessary to identify species compositions in specific habitats and species-habitat associations, particularly in the tropics, where such knowledge is still weak. We examined the dragonfly species composition of 133 localities in the arid environment of western Namibia. An analysis of nestedness indicated that distinct, and predictable patterns of species associations can be expected. Discriminant analyses revealed that most of the nine habitat types separated by structural and hydrological parameters are well discriminated by their dragonfly assemblages. Spring brooks in particular host a specific assemblage, which is threatened due to the habitat restriction of several species, as well as by recent habitat loss and degradation. Using a hierarchical method of several criteria we demonstrated the selection of a set of potential indicator species from the species set, most of these being useful indicators for spring brook assemblages. The conservation status of certain habitats and species is discussed. We propose that dragonflies will have a high indicator potential for threatened freshwater wetlands in such areas and may also serve as an indication of the sustainable use of water resources including evaluating measures to rehabilitate environments.     

Conservation of freshwater fish resources of India: new approaches, assessment and challenges

The freshwater resources of India are currently experiencing an alarming decline in fish biodiversity due to several factors and as a result, a sizeable portion of fresh water fishes have been categorized as threatened. This emphasizes an immediate need for initiating research and actions for alternative management techniques to protect these aquatic systems. One such option that has potential to protect freshwater ecosystem from numerous threats is the creation of freshwater aquatic sanctuary (FAS) within protected area network. Though similar conservation practices are well established in the terrestrial and marine ecosystem, however, the work on freshwater systems has been very slow and negligible. In the present communication we conceptualized the need and approach for developing FAS within the protected area network based on our observations in the water bodies of the selected wildlife sanctuaries in Northern India as well as success stories of some other countries. In this study we assessed the fish diversity in the selected protected areas of Northern India. The assessment indicated that these sanctuaries harbor 28.26–31.13% of freshwater fishes, which are threatened in other areas. Apart from Indian Major Carps, Tor putitora, Chitala chitala, Pangasius pangasius, Clupisoma gerua, Ailia coila, Aorichthys aor, Wallago attu, Rhinomugil corsula, Ompok pabda, Ombok pabo etc. were the important species encountered in the protected waters. The various issues related to FAS including objectives, approach, potential tools, implementation and management are discussed towards saving endangered fish germplasm resources. Approaches, tools and modus operandi proposed in this communication could be utilized by other developing countries in the region.     

Conservation of Freshwater Biodiversity: a Comparison of Different Area Selection Methods

The biodiversity of freshwater systems is endangered, especially in Mediterranean semiarid areas such as the south east of the Iberian Peninsula, whose rich and endemic biota is threatened by the development of surrounding land-crop irrigation. For this reason, the prioritization of areas for biodiversity conservation is an urgent target. In this study we used data records of water beetles from a province of the southeast of Spain for assessing priority areas for freshwater biodiversity conservation. We compare the performance of various area-selection methods, ranging from scoring procedures to complementarity-based algorithms, which are based on different criteria such as richness, rarity and vulnerability. The complementarity approaches were more efficient than methods using scoring or richness and rarity hotspots for representing conservation targets in a given number of areas and for identifying the minimum set of areas containing all species at least once. Within these, the richness-based algorithm was more efficient than rarity-based algorithm. Crucial target habitats for aquatic biodiversity conservation in the area studied are streams at medium altitude, hypersaline streams, and endorreic and karstic complexes.     

Can host body size explain the parasite species richness in tropical freshwater fishes?

Summary The variability of monogenean gill ectoparasite species richness in 19 West African cyprinid species was analyzed using the following seven predictor variables: host size, number of drainage basins, number of sympatric cyprinid species, host diversity, association with mainland forest, host ecology, and monogenean biological labelling. The size of the host species accounted for 77% of the variation in the number of parasite species per host, and host ecology an additional 8%. Together the effects of host size and host ecology accounted for 85% of the variation in monogenean species richness. This study shows that the deciding factors for explaining monogenean species richness in West African cyprinid fishes are host species size and host ecology. These results were compared with main factors responsible for parasite species richness in fish communities. Other possible explanations of monogenean community structure in west African cyprinids are discussed.     

A comparative measure of biodiversity based on species composition

In conservation planning, species richness and species endemism are the most often used metrics for describing the biodiversity importance of areas. However, when it comes to prioritizing regions for conservation actions these measures alone are insufficient because they do not reveal how similar or different the actual composition of species may be from one area to another. For comparative analysis an additional useful metric would be one that indicates the degree to which the species assemblage in one area is also represented in—or is distinct from—species assemblages of other areas. Here we describe a method for quantifying the compositional representativeness of species assemblages among geographic regions. The method generates asymmetric pairwise similarity coefficients that are then used to calculate separate measures for the representativeness and the distinctiveness of species assemblages in the regions being compared. We demonstrate the method by comparing fish communities among freshwater ecoregions of the Mississippi Basin, and then among smaller hydrological units within two individual freshwater ecoregions. At both scales of analysis, our measures of representativeness and distinctiveness reveal patterns of fish species composition that differ from patterns of species richness. This information can enhance conservation planning processes by ensuring that priority-setting explicitly consider the most representative and distinctive species assemblages.     

The influence of environmental factors and management methods on the vegetation of mesic grasslands in a central European mountain range

We examined how environmental factors combined with the diverse ways of the extensive management of mesic mountain grasslands affect species composition and diversity in the Polish part of Central Sudetes Mts. Based on the data from 100 research plots altitude, organic matter content and exchangeable magnesium in the soil, as well as the maximum soil water capacity and amount of sand fraction significantly affected species composition. Among the management methods, a significant effect on the differentiation of species composition was observed following the cessation of usage and mowing. Mown meadows had the highest share of forbs in the biomass, whereas those abandoned ones were dominated by tall and expansive grasses, mainly Calamagrostis epigejos. The species richest grasslands occurred in areas with soils of high water capacity, containing high concentrations of calcium and low amounts of total nitrogen. No significant effect of management methods on the total number of species as well as on the number of forb species was observed. Mown pastures had the highest mean value of the Shannon–Wiener diversity index.