Marine ecology: different measures of biodiversity

In their analysis of global trends of diversity in marine plankton, Irigoien et al. find that taxonomic diversity of zooplankton (consumer) is a unimodal function of community biomass that is unrelated to phytoplankton (producer) diversity. Their results are unexpected because in terrestrial organisms primary-producer diversity is a good predictor of consumer diversity. I contend that this apparent uncoupling of producer and consumer diversity in marine plankton is likely to be an artefact due to the authors' use of different measures of diversity for producers and for consumers.     

Changes in plant community diversity and aboveground biomass along with altitude within an alpine meadow on the Three-River source region

The grassland is an important component of terrestrial ecosystems and plays a significant role in biodiversity and ecosystem functions.In the present study,the changes of plant species diversity and aboveground biomass productivity were examined along with the altitude in natural alpine grassland in the source region of three rivers on the Qinghai-Tibetan Plateau.Eleven experimental locations were selected with altitudes ranging from 3862 to 4450 m above sea level(a.s.l.).The results indicated that Kobresia pygmaea meadow,Kobresia humilis meadow and Salix cupularis shrub meadow had higher indices of diversity and aboveground biomass.The distribution of species diversity,richness and aboveground biomass showed similarly unimodal patterns across the altitude gradient with the highest indices appeared at mid-altitudes locations.The changing trend of species diversity,richness and evenness also showed significant unimodal patterns with total aboveground biomass,and the highest species diversity occurred at intermediate level of productivities.This research would provide a valuable reference for the protection of grassland biodiversity and maintaining of the grazing ecosystem function in the source region of the Three Rivers.     

钦州湾近岸海域水质污染状况评价

【目的】调查及评价钦州湾近岸海域水质污染程度。【方法】2010年3月(春季)及2010年9月(秋季)在钦州湾近岸海域布设9个站位进行水质、浮游植物及浮游动物调查。采用水质综合污染指数及生物多样性指数对调查结果进行评价。【结果】钦州湾近岸海域春季、秋季水质综合污染指数平均值分别为3.20、3.68;浮游植物多样性指数分别为3.37、3.35;浮游动物多样性指数分别为2.33、2.89。【结论】以水质综合污染指数评价,2010年钦州湾近岸海域污染等级为轻污染;以浮游植物多样性指数评价,污染等级为轻度污染至无污染;以浮游动物多样性指数进行评价,污染等级为轻中污染。相对于浮游动物多样性指数,浮游植物多样性指数能更灵敏地指示和评价海洋环境的污染形势,但其评价标准和方法有待更多的调查和研究来进行验证和修正。单一利用生物多样性指数进行海域污染评价,具有一定的局限性,但仍可在一定程度上反映出海洋环境的污染程度。     

上海城区小型河道生物组成特征及食物链结构分析

2007年11月-2008年10月对上海市城区4条小型河道(曹杨环浜、午潮港、横港和朝阳河)中的生物组成进行了调查分析.结果共鉴得浮游植物268种,浮游动物157种,大型底栖动物21种,高等植物10种,鱼类13种.浮游植物包括绿、裸、硅、蓝、黄、隐、甲和金藻8个类群,其中以绿、裸、硅和蓝藻数量最多;浮游动物中原生动物、轮虫、枝角类和桡足类分别为94种(不含植鞭毛虫)、44种、13种和6种;底栖动物中软体动物14种,环节动物3种,甲壳动物和水生昆虫幼体各2种;鱼类包括7科,分别为鲤科、鳉科、塘鳢科、斗鱼科、(?)虎鱼科、鳢科和合鳃鱼科,其中鲤科最为丰富,占全部鱼种的53.8%;高等植物包括沉水植物4种、挺水植物4种及浮叶植物2种.曹杨环浜的浮游植物、浮游动物、底栖动物、鱼类和高等植物的种类均最为丰富,且浮游植物和鱼类的组成较均一,无明显优势种,高等植被密度大,以沉水植物为主;横港浮游生物种类最少,脊椎动物仅见外来小型鱼类食蚊鱼,高等植物则以挺水植物为主,分布区域较为集中;午潮港和朝阳河的浮游植物以蓝绿藻为优势种,高等植物分别仅1和2种,且密度小、覆盖率低.4条河道的生物食物链结构都趋于简单化,且能量输出方式较为单一.鉴于上述情况,建议在今后的生态修复中要因河道而异,适当改善底栖动物、鱼类和水生高等植物的组成结构,增加物种丰富度,促进食物链结构复杂化.     

生物多样性指数在生态评价中的实用性分析——以北部湾为例

为了探讨生物多样性指数(H′)在综合评价近岸海域的实用性,本研究利用水质综合污染指数和浮游植物、浮游动物及底栖生物的多样性指数分别对北部湾近岸海域调查的数据进行污染程度评价,并讨论利用多样性指数评价的合理性。结果表明:用水质综合污染指数评价2014年平水期北部湾近岸海域的水质结果为轻污染;用浮游植物和浮游动物的多样性指数评价结果均为轻中污染;用底栖生物的多样性指数进行污染评价结果则为重中污染。可见,生物多样性指数适用于污染程度较重的水域,而对于像北部湾近岸海域这样较洁净的水域,其与水质评价则存在较大的差异。结合我国近岸海域环境监测的实际情况,当前利用浮游植物来评价最具实用性。生物数据需建立在常年观测的基础上,并与理化监测结果结合起来开展综合性指标评价,才能正确地发挥其作用,从而得到符合实际的结论。     

A highly unsaturated fatty acid predicts carbon transfer between primary producers and consumers

The factors that regulate energy transfer between primary producers and consumers in aquatic ecosystems have been investigated for more than 50 years. Among all levels of the food web (plants, herbivores, carnivores), the plant-animal interface is the most variable and least predictable link. In hypereutrophic lakes, for example, biomass and energy transfer is often inhibited at the phytoplankton-zooplankton link, resulting in an accumulation of phytoplankton biomass instead of sustaining production at higher trophic levels, such as fish. Accumulation of phytoplankton (especially cyanobacteria) results in severe deterioration of water quality, with detrimental effects on the health of humans and domestic animals, and diminished recreational value of water bodies. We show here that low transfer efficiencies between primary producers and consumers during cyanobacteria bloom conditions are related to low relative eicosapentaenoic acid (20:5omega3) content of the primary producer community. Zooplankton growth and egg production were strongly related to the primary producer 20:5omega3 to carbon ratio. This indicates that limitation of zooplankton production by this essential fatty acid is of central importance at the pelagic producer-consumer interface.     

Predator diversity dampens trophic cascades

Food web complexity is thought to weaken the strength of terrestrial trophic cascades in which strong impacts of natural enemies on herbivores cascade to influence primary production indirectly. Predator diversity can enhance food web complexity because predators may feed on each other and on shared prey. In such cases, theory suggests that the impact of predation on herbivores relaxes and cascading effects on basal resources are dampened. Despite this view, no empirical studies have explicitly investigated the role of predator diversity in mediating primary productivity in a natural terrestrial system. Here we compare, in a coastal marsh community, impacts of arthropod predators on herbivores and plant productivity between a simple food web with a single predator species and a complex food web with a diverse predator assemblage. We show that enhancing predator diversity dampens enemy effects on herbivores and weakens trophic cascades. Consequently, changes in diversity at higher trophic levels can significantly alter ecosystem function in natural systems.     

胶州湾海岸湿地的生物多样性特征

通过实地调查并结合相关文献资料分析了胶州湾海岸湿地的生物多样性特征.对胶州湾海岸湿地生态系统结构和功能起重要作用的湿地生物有浮游植物、浮游动物、底栖动物、水禽和湿地维管束植物5大类.以硅藻和甲藻为主的浮游植物中广布种和暧温带种种类最多,以节肢动物和腔肠动物为主的浮游动物中近岸低盐种最多,底栖动物中温带种和广温广布种最多.以2003、2004年的调查结果与20世纪80年代的调查结果相比,胶州湾海岸湿地中的浮游植物、浮游动物和游泳生物种类都有明显地减少.胶州湾海岸湿地水禽包括游禽和涉禽2类,水禽区系的地理分布成分以古北界种类为主,季节型成分以旅鸟和候鸟为主.胶州湾海岸湿地维管束植物区系的生活型成分以地下芽植物和一年生植物为主,生态类群成分以水生植物和盐生植物为主,种子植物属的地理分布成分以世界分布属和温带分布属为主.     

渤海兴城-觉华岛海域海草床典型生物群落特征及其关键环境因子识别

海草床是近海重要、高产的生态系统，发挥着净化水质、维持生物多样性等多种生态功能．本文以渤海辽东湾觉华岛海域海草床为研究对象，分别于2020年8月和10月开展了海草床夏、秋两季的典型生物群落调查，阐明了该区域海草（鳗草（Zostera marina L.））、浮游植物、浮游动物、底栖生物等群落结构特征及时空差异，揭示了海草床典型生物群落特征与环境因子的响应关系．研究结果显示:觉华岛海域鳗草在夏季的茎枝长度、茎枝密度、生物量均显著高于秋季(P<0.05)；海草床内典型生物群落夏秋两季的Shannon-Wiener指数（H′）、Margalef丰富度指数（D′）、Pielou均匀度指数（J）分别在1.09~1.77、0.46~1.17、0.65~0.88间波动；其中浮游植物的H'在夏季低于秋季，而浮游动物和底栖动物均呈现相反趋势．RDA分析表明:沉积物沙含量、水体无机氮和pH是该区域海草生态学指标变化的主要环境因子；而水体总磷、无机氮和溶解氧是海草床内浮游生物和底栖生物群落特征变化的主要环境因子．      

Global environmental controls of diversity in large herbivores

Large mammalian herbivores occupy half of the earth's land surface and are important both ecologically and economically, but their diversity is threatened by human activities. We investigated how the diversity of large herbivores changes across gradients of global precipitation and soil fertility. Here we show that more plant-available moisture reduces the nutrient content of plants but increases productivity, whereas more plant-available nutrients increase both of these factors. Because larger herbivore species tolerate lower plant nutrient content but require greater plant abundance, the highest potential herbivore diversity should occur in locations with intermediate moisture and high nutrients. These areas are dry enough to yield high quality plants and support smaller herbivores, but productive enough to support larger herbivores. These predictions fit with observed patterns of body size and diversity for large mammalian herbivores in North America, Africa and Australia, and yield a global map of regions with potentially high herbivore diversity. Thus, gradients of precipitation, temperature and soil fertility might explain the global distribution of large herbivore diversity and help to identify crucial areas for conservation and restoration.     

海洋硅藻多样性与生态作用研究

硅藻是海洋浮游植物的主要类群,也是海洋生态系统中的主要初级生产者,在海洋生态系统的物质循环和能量流动中起着极其重要的作用,但人们对海洋硅藻多样性和生态作用的认识还很有限.在叙述海洋硅藻多样性、生态作用及硅藻分类学与系统学的国内外研究动态和最新进展的基础上,概述了厦门大学硅藻课题组近年来在海洋硅藻分类学与系统学、多样性与生态分布、硅藻数据库与计算机自动识别、微型硅藻与硅藻隐形种、硅藻遗传地理差异、硅藻对环境和气候变化的响应机制、硅藻细胞硅吸收与硅质壁形成机制等方面的主要研究进展和取得的主要成果.     

海洋浮游动物学研究

中国的海洋浮游生物学由我们已故科学家郑重、金德祥教授创建于本世纪40年代。近10年来,该领域继续取得一批研究成果,促进了我国海洋浮游生物学的发展。在浮游动物生物学方面,揭示了台湾海域及其邻近海域浮游动物多样性,发现水母类39个新种,桡足类2个新种,并对浮游动物生态类群、群落结构、微小型浮游动物在生态系统中的地位和作用等基础生态学取得了系列成果。同时,开展了实验生理生态学及个体生物学研究。其中,浮游动物生化组成与生理生态功能、浮游桡足类卵型与滞育、浮游动物能学、主要浮游动物染色体、生活周期与世代,摄食生态,经济贝类幼体附着与变态等研究。     

The discovery of Jurassic plants in Shenzhen of Guangdong,southern China and related significance

Investigations of major marine and non-marine geologic and biotic events across the Triassic-Jurassic transition rely predominantly on detailed stratigraphic frameworks and biodiversity analyses. The alternating sequences of marine and terrestrial Triassic-Jurassic for- mations in Guangdong Province represent one of the most remarkable coal-bearing series in southern China. The Lower Jurassic Jinji Formation is widely distributed in Guangdong, with continuously outcropped sections and rich marine and non-marine fossil fauna. However, as little research has been conducted on fossil plant remains in the Jinji Formation, it is difficult to understand the systematics, diversity, and floral aspects of the Jurassic. Here we report on the recent collection of rich fossil plants from the Jinji Formation in the Dapeng area of Shenzhen, southern Guangdong Province. Our studies demonstrate taxonomical affiliations, preservation status, and diversity features of these plant fossils, which are marked by the close associ- ation of densely preserved, pinnae and rachis connected leaves, and the bennettitalean reproductive organs of Wil- liamsoniella, which may represent an Early Jurassic plant community dominated by Otozamites of the bennettitales. This work not only represents the first discovery of fossil plants in the Shenzhen area, but is also the first docu- mentation of Jurassic plants in Guangdong and the Pearl River Delta regions. Research related to these plant fossils will be helpful in the correlation of the Early Mesozoiccoal-bearing strata in Guangdong, and will provide a dee- per understanding of variations in plant diversity of the Triassic and Jurassic transition in southern China. Addi- tionally, it will provide terrestrial plant evidence for explorations in Jurassic palaeoecology, palaeoclimatology, and palaeogeography of southern China.     

条子泥围垦工程对近海生态环境的影响

以条子泥一期围垦为研究对象,通过对工程前后近海浮游植物、浮游动物、大型底栖动物及潮间带底栖生物进行取样调查,分析围垦前后的生态特性差异。结果表明:围垦后浮游植物群落种类及生物密度有所增加,且种类组成发生变化;垦区附近浮游动物种类增多,优势种发生变化;底栖生物种类数减少,仍以甲壳动物为主,相对于围垦前的均匀分布,围垦后仅在部分站位监测到;潮间带底栖生物种类减少,但仍以四角蛤蜊等经济贝类为主,生物密度和生物量变化较小。围垦改变生态环境中水动力、悬浮物、沉积物特性等多种环境因子,造成水生生物群落结构及多样性的变化。     

Copepod hatching success in marine ecosystems with high diatom concentrations

Diatoms dominate spring bloom phytoplankton assemblages in temperate waters and coastal upwelling regions of the global ocean. Copepods usually dominate the zooplankton in these regions and are the prey of many larval fish species. Recent laboratory studies suggest that diatoms may have a deleterious effect on the success of copepod egg hatching. These findings challenge the classical view of marine food-web energy flow from diatoms to fish by means of copepods. Egg mortality is an important factor in copepod population dynamics, thus, if diatoms have a deleterious in situ effect, paradoxically, high diatom abundance could limit secondary production. Therefore, the current understanding of energy transfer from primary production to fisheries in some of the most productive and economically important marine ecosystems may be seriously flawed. Here we present in situ estimates of copepod egg hatching success from twelve globally distributed areas, where diatoms dominate the phytoplankton assemblage. We did not observe a negative relationship between copepod egg hatching success and either diatom biomass or dominance in the microplankton in any of these regions. The classical model for diatom-dominated system remains valid.     

北麂列岛附近海域海洋生态环境现状

2013年11月对北麂列岛附近进行水质、沉积物和海域生态环境现状(浮游植物、浮游动物和底栖生物)进行了调查研究,结果表明:按照一类海洋功能标准,水质中无机氮和磷酸盐严重超标,锌部分站位超标。浮游植物45种,以硅藻类为主,占88.4%。大型浮游动物26种,以桡足类为主,占34.6%。大型底栖生物11种,以软体动物和多毛类为主,各占45.5%。浮游植物、浮游动物和底栖生物的生物多样性指数偏低。     

Global tests of biodiversity concordance and the importance of endemism

Understanding patterns of biodiversity distribution is essential to conservation strategies, but severe data constraints make surrogate measures necessary. For this reason, many studies have tested the performance of terrestrial vertebrates as surrogates for overall species diversity, but these tests have typically been limited to a single taxon or region. Here we show that global patterns of richness are highly correlated among amphibians, reptiles, birds and mammals, as are endemism patterns. Furthermore, we demonstrate that although the correlation between global richness and endemism is low, aggregate regions selected for high levels of endemism capture significantly more species than expected by chance. Although areas high in endemism have long been targeted for the protection of narrow-ranging species, our findings provide evidence that endemism is also a useful surrogate for the conservation of all terrestrial vertebrates.     

Macroecological patterns of phytoplankton in the northwestern North Atlantic Ocean

Many issues in biological oceanography are regional or global in scope; however, there are not many data sets of extensive areal coverage for marine plankton. In microbial ecology, a fruitful approach to large-scale questions is comparative analysis wherein statistical data patterns are sought from different ecosystems, frequently assembled from unrelated studies. A more recent approach termed macroecology characterizes phenomena emerging from large numbers of biological units by emphasizing the shapes and boundaries of statistical distributions, because these reflect the constraints on variation. Here, I use a set of flow cytometric measurements to provide macroecological perspectives on North Atlantic phytoplankton communities. Distinct trends of abundance in picophytoplankton and both small and large nanophytoplankton underlaid two patterns. First, total abundance of the three groups was related to assemblage mean-cell size according to the 3/4 power law of allometric scaling in biology. Second, cytometric diversity (an ataxonomic measure of assemblage entropy) was maximal at intermediate levels of water column stratification. Here, intermediate disturbance shapes diversity through an equitable distribution of cells in size classes, from which arises a high overall biomass. By subsuming local fluctuations, macroecology reveals meaningful patterns of phytoplankton at large scales.     

Consistent patterns and the idiosyncratic effects of biodiversity in marine ecosystems

Revealing the consequences of species extinctions for ecosystem function has been a chief research goal and has been accompanied by enthusiastic debate. Studies carried out predominantly in terrestrial grassland and soil ecosystems have demonstrated that as the number of species in assembled communities increases, so too do certain ecosystem processes, such as productivity, whereas others such as decomposition can remain unaffected. Diversity can influence aspects of ecosystem function, but questions remain as to how generic the patterns observed are, and whether they are the product of diversity, as such, or of the functional roles and traits that characterize species in ecological systems. Here we demonstrate variable diversity effects for species representative of marine coastal systems at both global and regional scales. We provide evidence for an increase in complementary resource use as diversity increases and show strong evidence for diversity effects in naturally assembled communities at a regional scale. The variability among individual species responses is consistent with a positive but idiosyncratic pattern of ecosystem function with increased diversity.     

Low host specificity of herbivorous insects in a tropical forest

Two decades of research have not established whether tropical insect herbivores are dominated by specialists or generalists. This impedes our understanding of species coexistence in diverse rainforest communities. Host specificity and species richness of tropical insects are also key parameters in mapping global patterns of biodiversity. Here we analyse data for over 900 herbivorous species feeding on 51 plant species in New Guinea and show that most herbivorous species feed on several closely related plant species. Because species-rich genera are dominant in tropical floras, monophagous herbivores are probably rare in tropical forests. Furthermore, even between phylogenetically distant hosts, herbivore communities typically shared a third of their species. These results do not support the classical view that the coexistence of herbivorous species in the tropics is a consequence of finely divided plant resources; non-equilibrium models of tropical diversity should instead be considered. Low host specificity of tropical herbivores reduces global estimates of arthropod diversity from 31 million (ref. 1) to 4 6 million species. This finding agrees with estimates based on taxonomic collections, reconciling an order of magnitude discrepancy between extrapolations of global diversity based on ecological samples of tropical communities with those based on sampling regional faunas.