天津海域自由生活线虫分类学多样性

在我国海域进行了很多自由生活线虫的研究,但是线虫分类学多样性的报道极少。2007年春季在天津海域的15个站位进行了底栖生物调查,对自由生活线虫样品进行了分类学多样性的分析。共鉴定出自由生活线虫87种,隶属于2纲2亚纲5目7亚目14科39属。以色矛纲(Chromadorea)线虫居多,有74种,占总种数的85%。线虫平均分类学差异性指数(Δ+)的理论平均值为60.5,分类学差异性变异(Λ+)的理论平均值约为420。平均分类学差异性指数值随站位而变,变化幅度为49.8~63.0;各站位分类学差异性变异的波动范围较大,从233到514不等。这些结果表明,线虫在一些站位的分类学信息有较大的不同。漏斗图显示,西南部近岸海域的线虫群落组成的分类学多样性较差,预示着环境受到干扰。线虫在西南部近岸4个站位的分类学差异性受到了化学因素的影响,多个化学指标具有较高值;同时也与沉积物的粒径和叶绿素含量有一定关系。与一些传统多样性指数比较,分类学差异性指数在反应环境差异方面有较好的灵敏性。     

不同采样时期渤海自由生活海洋线虫种类组成的比较

在渤海的3个典型站位B1、E5和E1,以3个不同采样时期的沉积物样品（1997年6月、1998年9-10月份和1999年4-5月份）,研究了渤海自由生活海洋线虫的种类组成变化。结果表明：自由生活海洋线虫的摄食类型比例在同一个站位3次不同采样均有变化,其中B1站和E5站3个采样时期表现为3种不同的摄食类型分布;将线虫分为3个时期所进行的年龄结构和雌雄比研究表明,在线虫群落中幼龄个体一般占到线虫群落总数的一半以上;对3个站位线虫群落的多样性研究表明,离黄河口最近的B1站,出现种类数量最少,位于渤海中部的E5站,出现种类数量较多;3个不同采样时期的比较,以1997年6月份群落中出现的种类数最多,1999年4-5月份出现的最少。对其群落结构的分析表明,同一个站位不同采样时期,优势种的类型基本相同,变化主要表现在优势种丰度大小的差异,其群落组成结构相对稳定。     

大亚湾表层沉积物和底栖生物中重金属的污染特征与生物积累

通过分析2015 年5 月大亚湾海域34 个采样站位表层沉积物和底栖生物生物体中5 种重金属(铜、铅、锌、镉、汞)的综合污染程度因子、潜在生态风险因子和生物-沉积物积累因子, 评估了大亚湾海域表层沉积物重金属的污染现状、潜在生态风险水平和生物-沉积物积累程度。结果表明: 大亚湾海域表层沉积物中重金属含量上呈现锌>铅>铜>镉>汞的规律; 空间上呈带梯度带分布: 北部沿岸海域含量较高, 南部口门附近海域最低。重金属污染属于中等-比较严重污染水平, 其中锌、镉、汞是大亚湾沉积物污染的主要因子, 潜在生态风险属于中等-较高风险水平, 汞、镉是较大的潜在风险因子。底栖生物生物体重金属含量上呈现锌>铜>铅>镉>汞。铜、铅、锌、汞四种重金属除铜、锌在棒锥螺(Turritella terebra)生物体轻度积累外, 其它均无明显积累表现, 而重金属镉呈现较强的积累现象。     

深圳湾表层沉积物中甲藻孢囊的垂直分布

采集了深圳湾3个采样点约20cm的表层沉积物样品,研究了甲藻孢囊的垂直分布。共分析鉴定出孢囊类型37种,其中5种为我国沿海未报道的新记录类型,原多甲藻类孢囊是该海域种类最丰富的孢囊类型。除上表层沉积物外,深圳湾甲藻孢囊密度较低,孢囊密度大多在500cysts／gDWt以下,总孢囊密度变化范围为83～4036cysts／gDWt之间。锥状斯氏藻是深圳湾甲藻孢囊的优势种类,上表层沉积物中该孢囊密度的急剧上升证实了2000年附近海域所发生的该藻赤潮。而裸甲藻类孢囊含量明显比南海其他海域高。孢囊的香农-威弗种类多样性指数为1．50～3．96之间,并且在非养殖区、离岸海域及较深层次沉积物中较高,而孢囊密度则呈相反的变化趋势。种类多样性的下降及孢囊密度的上升在一定程度上说明深圳湾污染的变化趋势,富营养化程度非养殖区大于养殖区,近岸海域大于离岸海域,并且近年来污染逐渐加剧。     

渤海线虫群落的多样性及中性模型分析

对渤海的黄河口水下三角洲、莱州湾和渤海中部共9个站位的海洋线虫群落的多样性进行了研究.用于比较的海域和站位还包括1995年胶州湾的95B2站和1988年湄州湾的A01站.以上11个站位共鉴定出自由生活海洋线虫154种,分属于107属29个科.使用种丰度(SR),香农-维弗指数(H′)和均衡度(J)用来比较不同生境的生物多样性.不同生境和站位的生物多样性水平由高到低依次为渤海中部(9761、DA18、DA19和DA20,SR=8.60±0.84,H′=4.94±0.23)、莱州湾(9762、DA2和DA4,SR=6.48士0.40,H′=3.95±3.0)和黄河口水下三角洲(E9和E11,SR=4.18±0.56,H′=3.60±0.24).线虫生物多样性与海水的盐度和沉积物的异质性指数(h)呈显著的负相关(P≤0.01).Caswell 中性模型分析指明,大部分研究站位的"V"值为"-2～+2",说明未受到显著外界因子的扰动.渤海中部的9761站的"V"值为2.054,暗示环境稳定性的增强,而莱州湾的DA4站"V"值为-2.624指明受到外界环境因子的显著影响,可能与黄河口输送大量的物质有关.     

藏东南急尖长苞冷杉林林隙土壤线虫群落特征

为了解西藏东南部急尖长苞冷杉林林隙土壤线虫群落特征,对林隙、非林隙土壤0~30 cm范围内不同深度土层的线虫群落进行调查,并用线虫个体密度、生物多样性指数和营养类群指数等特征值分析了土壤线虫群落的结构及多样性特点.结果表明： 采用浅盘法分离得到土壤线虫26801 条,隶属于2纲5目40科64属;线虫个体密度平均为3552 条·100 g-1干土,表聚性极强.垫咽属、丝垫刃属为林隙土壤线虫优势属;食细菌性线虫为主要营养类群.土壤有机质的分解兼有真菌分解和细菌分解两种途径.线虫的生物多样性及丰富度与林隙面积有关.土壤线虫群落特征表明,林隙具有异于郁闭林分和林间空地的特性,在环境指示方面具有应用潜力.     

苍南海洋倾倒区沉积物中酸可挥发性硫化物与重金属的研究

为了更清楚认识倾倒区海域沉积物的污染状况,测定了苍南海洋倾倒区海域表层沉积物中酸可挥发性硫化物(AVS)、酸可提取重金属(SEM)的含量,并对AVS、SEM、及ΣSEM-AVS的平面分布进行分析.结果表明,该倾倒区表层沉积物中AVS含量为0.19-1.88μmol·g^-1,倾倒区附近海域AVS含量高于周边海域;SEM平均含量为2.4μmol·g^-1,SEM含量往倾倒区方向有增加趋势.从单个重金属对ΣSEM的贡献率来看,Zn>Cr>Cu>Pb>Cd,SEMZn基本在50%以上,而SEMCd均在1%以下,其分布形态主要受Zn的控制.ΣSEM-AVS差值均大于0,且在倾倒区及附近海域其ΣSEM-AVS值高于沿岸各站,说明倾倒区海域沉积物中重金属对生物可能有一定毒性,具有潜在重金属生态风险.     

海洋微型底栖生物的多样性与地理分布

海洋微型底栖生物是指生活于海洋沉积物中及表面的所有单细胞原核和真核微型生物,包括原核微生物、真核微藻及原生动物等光合自养和异养的类群.与水体相比,海洋底栖生境孕育了形态和功能多样性更高的微型生物,在陆架浅海单位体积沉积物中其丰度较之水体中同类生物高一至几个数量级,而深海则孕育着特殊进化环境下新奇多样且数量庞大的微型底栖生物,是维持海洋生物多样性、海洋生态系统结构和功能不可或缺的部分.迄今对于微型生物是全球性还是限定性分布一直存在争议,对其解答受到分类研究欠缺及采样不足的制约.分子生物学从正反两方面提供了理论依据,但无法得出一个普遍接受的观点.海洋微型底栖生物的多样性研究侧重于物种多样性及群落结构与分子多样性,较为显著的进展体现在原核微生物的分子多样性及底栖真核微藻的物种多样性研究,对于海洋底栖原生动物的多样性研究则相较滞后.本文综述了国内外对海洋微型底栖生物各主要类群的分类学和多样性研究进展,探讨了各类群在全球的潜在物种多样性,并就我国未来加强海洋微型底栖生物多样性构成、分布与变动及驱动变化的因子以及底栖微食物网的研究提出了建议.     

长江口及毗邻海域沉积物生态环境质量评价

采用地质累积指数法、潜在生态危害指数法和生物效应浓度法3种方法,考虑河口的水动力过程、沉积物分布和盐度影响,把长江口及毗邻海域划分为7个区域进行沉积物生态环境质量评价.结果表明,3种方法评价结果基本一致,长江口及毗邻海域的底质生态环境均受到重金属不同程度的污染,属于中低度污染,口外区和舟山海区的沉积物质量较好,口门、最大浑浊带和杭州湾的沉积物质量较差.用同期的底栖动物群落结构参数进行验证,生态响应明显.     

深圳湾福田红树林湿地小型底栖动物群落结构及海洋线虫新纪录种

于2018年冬季在福田红树林湿地设置4个采样断面进行沉积物样品采集,对小型底栖动物的类群组成、丰度及自由生活海洋线虫的优势属等进行分析。结果表明:共鉴定出4个以上的小型底栖动物类群,分别为海洋线虫、桡足类、多毛类、寡毛类和其他未鉴定类群,海洋线虫为最优势类群,占小型底栖动物丰度的97.28%;小型底栖动物平均丰度为(490.73±465.09) ind·10 cm-2;共鉴定出海洋线虫隶属于30属17科,其优势属(优势度≥5%) Paracanthonchus、Megadesmolaimus、Subsphaerolaimus、Terschellingia、Spinonema、Pseudochromadora和Pseudolella;发现新纪录种—大亚囊咽线虫Subsphaerolaimus major NguyenGagarin,2009,并对其进行了测量及描述,并比较了其与模式种的主要差异。     

天津海域底栖线虫群落结构的多元统计分析

应用多元统计分析方法(等级聚类分析和非度量多维标度)研究了天津近岸海域的底栖线虫群落结构情况.结果表明,等级聚类分析和非度量多维标度分析的结果具有很好的一致性.15个取样站位的线虫群落存在差异,根据线虫种类组成和丰度不同,调查站位可以分为4组.中南部近岸海域多数站位的线虫种类组成相似,深水区域的底栖线虫种类变化最大,而北部湾顶海域的线虫组成近似,但与其他站位相差较大.     

Biodiversity loss decreases parasite diversity: theory and patterns

Past models have suggested host-parasite coextinction could lead to linear, or concave down relationships between free-living species richness and parasite richness. I explored several models for the relationship between parasite richness and biodiversity loss. Life cycle complexity, low generality of parasites and sensitivity of hosts reduced the robustness of parasite species to the loss of free-living species diversity. Food-web complexity and the ordering of extinctions altered these relationships in unpredictable ways. Each disassembly of a food web resulted in a unique relationship between parasite richness and the richness of free-living species, because the extinction trajectory of parasites was sensitive to the order of extinctions of free-living species. However, the average of many disassemblies tended to approximate an analytical model. Parasites of specialist hosts and hosts higher on food chains were more likely to go extinct in food-web models. Furthermore, correlated extinctions between hosts and parasites (e.g. if parasites share a host with a specialist predator) led to steeper declines in parasite richness with biodiversity loss. In empirical food webs with random removals of free-living species, the relationship between free-living species richness and parasite richness was, on average, quasi-linear, suggesting biodiversity loss reduces parasite diversity more than previously thought.     

Free-living marine nematodes from San Julián Bay (Santa Cruz,Argentina)

The free-living marine nematodes of San Julián Bay dataset is based on sediment samples collected in January 2009 during the project PICT AGENCIA-FONCYT 2/33345-2005. A total of 36 samples have been taken at three locations in the San Julián Bay, Santa Cruz Province, Argentina on the coastal littoral at three tidal levels. This presents a unique and important collection for the nematode benthic biodiversity assessment as this area remains one of the least known regions in Patagonia. In total 10,030 specimens of free-living marine nematodes belonging to 2 classes, 9 orders, 35 families, 78 genera and 125 species were collected. The San Julián city site presented a very high species richness.     

基于优势种的生物多样性保护价值空间异质性研究——以长白山生态功能区为例

生物多样性保护是生态系统的主导功能之一,对生物多样性空间异质性的研究有助于准确认识区域的保护价值及重要性,但目前可借鉴的生物多样性价值空间异质性评价方法和经验偏少。以长白山生态功能区核心区为研究区域,基于生物多样性丰富区域优势物种的分布及其环境因子,通过Maxent评估生物多样性保护价值,将研究区域分为生物多样性保护高价值区、中价值区和一般价值区,并开展景观分析与评估。研究结果表明:研究区域内生物多样性保护高价值区域占总面积的42.9%、主要分布于长白山保护区内,保护区内的高价值斑块也较保护区外完整、面积大;研究区域内生物多样性高价值斑块的平均面积和最大斑块面积远高于中价值区和一般价值区,其斑块景观较完整、破碎化水平相对较低,是研究区域生物多样性保护价值和生态系统稳定性的重要基础。植被是对研究区域生物多样性影响最大的环境因子,其次是土层厚度和海拔。从生态系统完整性和过程连续性保护的需要,保护区南部缓冲区可考虑调整为核心区,保护区外还有较大面积的生物多样性高价值和中价值区域也应纳入保护区进行保护;长白山西坡是生物多样性高价值斑块最破碎的区域,应在未来的保护工作中予以特别关注。本研究表明关联优势种空间分布及环境因子是认识生物多样性价值及空间异质性的有效手段,本研究方法可为生态红线划定和国家公园设计提供参考。     

Invasion of a Habitat-Forming Seaweed: Effects on Associated Biota

Fucus evanescens is a brown alga of arctic origin that has invaded European coasts. The epiphytic community of F. evanescens in southern Sweden was compared with that of the native Fucus vesiculosus, to examine to what extent an invading seaweed can modify local biodiversity. F. evanescens was much less fouled than F. vesiculosus, supporting both less biomass and fewer species of epiphytes. Multivariate analysis of the most common epiphyte taxa showed that the epiphytic community composition of F. evanescens was not entirely separated from that of F. vesiculosus, but host species contributed significantly to explain the variation in community composition. The biomass of free-living invertebrates was also lower on F. evanescens, although the pattern differed between taxonomic groups. While the biomass of amphipods was lower on F. evanescens, there was no significant difference in biomass of isopods or gastropods between the Fucus species. The good correlation between biomass of epiphytes and free-living animals suggests that the epiphytes play an important role in providing a suitable habitat for many species of free-living epifauna. The study shows that the invasion of F. evanescens affects the environmental conditions for many species associated with the Fucus community but that the direct effect on biodiversity is probably low.     

陕西汉中天坑群维管植物多样性及区系分析

对陕西汉中典型天坑生物多样性进行调查，并在系统收集天坑周边生物多样性研究成果与资料的基础上，对该区维管植物多样性区系进行初步研究。结果表明，汉中天坑群区域有被子植物940种，裸子植物20种，蕨类植物73种。该区植物区系以温带成分为主，兼具热带成分，展示了明显的由暖温带向亚热带过渡的特点，且区系具有一定的古老性。天坑群已发现30种珍稀濒危植物，是现存珍稀濒危植物的“避难所”。该研究对探究天坑群地区生态资源可持续发展利用、天坑生物多样性的保育以及恢复重建等方面具有重要意义。     

南黄海冬季小型底栖生物丰度和生物量

分别于2003年1月和2004年1月在南黄海广大陆架浅海水域进行小型底栖生物调查.结果表明,两个航次的小型底栖生物平均丰度分别为 (954.20±269.47) ind·10 cm^-2和(1 186.12±486.07) ind·10 cm^-2;平均生物量分别为(954.38±403.93)μg·10 cm^-2和(1 120.72±487.21) μg·10 cm^-2.两个航次小型底栖生物丰度值、生物量和生产力均无显著变化(P>0.05).共鉴定出20个小型底栖生物类群,按丰度,自由生活海洋线虫为最优势类群,两个航次的优势度分别为87%和90%,其他优势类群依次为桡足类、多毛类和动吻类;按生物量依次为线虫34%～38%,多毛类25%～33%,介形类9%～22%,桡足类8%.96.64%的小型生物分布在0～5 cm的表层沉积物内,线虫和桡足类分布在0～2 cm的比例分别为72.48%和89.46%.小型底栖生物的生物量与沉积物砂含量(%)、粉砂含量(%)和叶绿素a含量呈显著相关.代表性站位的种类组成和多样性分析显示了沿岸、黄海冷水团和东、黄海交汇区3个不同的底栖生物群落.     

菲律宾海脊索动物多样性评估: 基于OBIS数据库

菲律宾海邻近全球生物多样性和进化的中心, 分布着多种重要生物资源。了解本区生物多样性及受威胁物种的分布特征可对掌握其生物多样性现状, 以及未来实施有效的生物多样性保护管理策略提供重要依据。本文利用海洋生物地理信息系统(Ocean Biogeographic Information System, OBIS)数据库, 并参考世界自然保护联盟濒危物种红色名录(IUCN Redlist)的物种濒危程度评估结果, 构建了菲律宾海脊索动物生物多样性和受威胁物种数据库, 结合海洋生态因子特征对该海区脊索动物的物种多样性和不同等级受威胁物种的数量空间分布格局进行了初步分析, 并对脊索动物不同分类阶元生物多样性与生态因子的关系进行了相关性分析。结果表明, 本区海洋脊索动物门已报道11纲56目320科1,171属2,876种。其中在菲律宾海的边缘区域, 特别是菲律宾群岛、台湾岛、日本群岛、马里亚纳群岛及中央的九州-帕劳海脊附近海域, 生物多样性水平相对较高, 而中央海盆区的生物多样性较低。本海域鱼类生物多样性尤其丰富, 共计4纲45目292科1,105属2,768种, 在物种水平上占本区脊索动物物种数的96%。各分类阶元水平的多样性与初级生产力呈显著正相关, 而与水深呈显著负相关。本区脊索动物门受威胁物种共计54种, 其中极危3种、濒危5种、易危22种、近危24种, 分别约占全区脊索动物总种数的0.10%、0.17%、0.76%、0.83%。与本区生物多样性分布格局相似, 受威胁物种多分布于菲律宾海边缘区域, 在中央海脊和深水盆地区域分布较少。本研究表明, 对菲律宾海脊索动物特别是受威胁物种的保护应当以边缘区域优先; 但考虑到当前菲律宾海深海区域生物多样性数据的不足, 也应加强对中央海脊和深水盆地等区域的生物多样性普查。     

Biodiversity of marine nematodes in Australian sandy beaches from tropical and temperate regions

The universal occurrence and abundance of nematodes provides opportunities to investigate ecological factors that may influence biodiversity. Clarke and Warwick (2001) have proposed diversity indices average taxonomic distance(AvTD), variation in taxonomic distinctness (VarTD) for computing marine nematode biodiversity based on classification trees. Faith [Biological Conservation 61 (1992) 1] had previously proposed a diversity index based on phylogenetic trees, though not applied to nematodes. Clarke and Warwick (2001) also considered an index AvPD analogous to AvTD. These indices have been applied to five very large collections of free-living nematodes from three exposed sandy beaches in Australia. Two were from a beach close to Darwin in northern Australia, two from the temperate southeast coast of Australia and one from the south of the Australian mainland. The collections extend over a considerable range of latitude, from 12°26S to 38°33S and the controversial hypothesis that latitudinal gradients per se influence the biodiversity of marine nematode assemblages is examined. AvTD did not vary among collections and its value for any collection was indistinguishable from that of random samples of the same size drawn from the total species pool. VarTD showed no variation for three of the collections, but was slightly higher than expected for the mid-latitude beach, attributed to unevenness in the classification trees. AvTD and VarTD were not greatly affected by differences in sampling intensity. PD varied directly with the number of species found but observed PD did not differ from the PD of random samples of the same number of species taken from the total species pool. Thus, the observed variation in PD is wholly accounted for by variations in species richness. The number of species found increased with decreasing latitude. It appears that species richness by itself is an adequate index of biodiversity for the free-living nematodes of these sandy beaches, and more complex indices such as AvTD, VarTD and PD are unnecessary.     

Biodiversity of Jinggangshan Mountain: The Importance of Topography and Geographical Location in Supporting Higher Biodiversity

Diversity is mainly determined by climate and environment. In addition, topography is a complex factor, and the relationship between topography and biodiversity is still poorly understood. To understand the role of topography, i.e., altitude and slope, in biodiversity, we selected Jinggangshan Mountain (JGM), an area with unique topography, as the study area. We surveyed plant and animal species richness of JGM and compared the biodiversity and the main geographic characteristics of JGM with the adjacent 4 mountains. Gleason’s richness index was calculated to assess the diversity of species. In total, 2958 spermatophyte species, 418 bryophyte species, 355 pteridophyte species and 493 species of vertebrate animals were recorded in this survey. In general, the JGM biodiversity was higher than that of the adjacent mountains. Regarding topographic characteristics, 77% of JGM’s area was in the mid-altitude region and approximately 40% of JGM’s area was in the 10°–20° slope range, which may support more vegetation types in JGM area and make it a biodiversity hotspot. It should be noted that although the impact of topography on biodiversity was substantial, climate is still a more general factor driving the formation and maintenance of higher biodiversity. Topographic conditions can create microclimates, and both climatic and topographic conditions contribute to the formation of high biodiversity in JGM.