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1.
The EC Water Framework Directive (WFD) suggests using abundance and species composition of intertidal seaweed communities for ecological quality classification of rocky seashores. There are two difficulties with this. According to WFD all sensitive species should be present on a shore. There is no accepted list of sensitive seaweed species and those which may be sensitive in one location may not be so in another. Second, natural successions can result in very large abundance changes of common species, e.g. from almost completely fucoid-dominated shores to almost totally barnacle-dominated shores, without any change in ecological quality. Studies have shown that numerical species richness, not the list of actual species present, is broadly constant in the absence of disturbance. The ephemeral species, possibly the sensitive members of the community, change regularly in such a way as to conserve species richness. It is proposed that species richness on a defined length of shore be used as a criterion of ecological quality. A database of species found on over 300 shores in the British Isles, under strictly controlled sampling conditions, has given ranges of values of species richness to be expected and has allowed for variations in these values due to sub-habitat variability, wave exposure and turbidity to be factored in. A major problem in applying such a tool is the lack of expertise of many workers in critical identification of seaweed species. A reduced species list has been extracted from the database using species commonly present and identifiable with reasonable certainty. A numerical index of ecological quality is proposed based on scores for various aspects of the physical nature of the habitat combined with a score for species richness which may be based on the reduced species list. The scoring system also uses further aspects of community structure, such as ecological status groups and the proportions of rhodophyta, chlorophyta and opportunist species. For this system to be effective there has to be close control of the way in which sampling is carried out to ensure a uniform level of thoroughness. 相似文献
2.
氮、磷供给比例对实验微藻群落结构的影响 总被引：1，自引：1，他引：0
生态理论预测,生境筛选和物种竞争可能会联合影响生物群落结构.然而,通过实验手段检测两者对群落结构的影响作用,特别是两者的作用效果是否会随时间推移而发生改变的研究还十分有限.本研究构建了实验微藻群落系统,通过改变微藻生长发育所必须的2种限制性因子氮素和磷素的供给比例,对微藻的结构特征及各微藻组分的种群动态变化进行持续跟踪,并通过对各微藻进行单一培养的方式来获取相关的性状指数,用以反映各微藻的耐低氮或耐低磷能力,进而检验生境筛选和物种竞争对微藻群落的影响作用,以及两者作用效果随时间推移而发生的改变.结果表明,生境筛选和物种竞争对微藻群落结构的影响会随着时间的推移而发生变化:实验初期生境筛选和物种竞争的影响作用均较弱;实验中期生境筛选发挥着较为重要的作用,具体表现在水体中氮素和磷素的供给比例直接影响了具有不同耐低氮或耐低磷能力的微藻种群数量分布;而实验末期物种竞争发挥着较为关键的作用,其中纤细角星鼓藻成为绝对优势种,而部分微藻因为竞争排斥作用而从系统中消失.未来的研究应全面考虑不同的时序变化和空间结构下生境筛选和物种竞争对群落结构的综合影响作用. 相似文献
3.
Zoosporic aquatic fungi growing on dead specimens of 29 freshwater crustacean species 总被引：1，自引：0，他引：1
The authors investigated aquatic fungi growing on the carapaces of 29 species of dead crustaceans (13 species of Copepoda, 13 species of Cladocera and 3 species of Ostracoda) in the water from six limnological and trophical different water bodies (two springs, one river, one lake and two ponds). All of these waterbodies are strongly loaded. 146 species of aquatic fungi were found on the carapaces: 40 Chytridiomycetes, 1 Hyphochytriomycete and 105 Oomycetes. The most common fungus species were Karlingia chitinophila, Myzocytium microsporum, Myzocytium zoophthorum, Pythium acanthicum, Pythium butleri and Pythium myriotylum. Most zoosporic fungus species were observed on the specimens of Daphnia pulex (50 fungus species), Daphnia magna (48) and Cyclocypris laevis (44), fewest on Cyclops fuscus and Cyclops vicinus (each 10).The most fungi were growing in the water from River Supraśl (86), the fewest in the water from Pond Fosa (53). Cluster analysis of the investigated parameters carried out in water bodies during the experiment on zoosporic fungus species has revealed that in the water from springs and Pond Fosa the number of fungus species is closely associated with the concentration of sulphates, in water from River Supraśl and Lake Komosa with calcium and in the water from Pond Dojlidy with chlorides. Out of these 146 species, 21 are known as parasites or necrotrophs of fish. Some dead specimens of crustacean species are a new substrate for some fungus species. 相似文献
4.
三峡水库童庄河浮游植物及其与水质的关系 总被引：6，自引：1，他引：5
通过对三峡水库支流童庄河库区的浮游植物进行调查,共检出浮游植物132种,其中蓝藻门23种,隐藻门2种,甲藻门3种,硅藻门55种,裸藻门3种,绿藻门46种.其中硅藻门的种类居首位,甲藻和隐藻则在数量上占优势.主要优势种为飞燕角甲藻(Ceratium hirundinella)和隐藻一种(Cryptomonas sp.).浮游植物的种类和数量随季节和水域不同而呈现差异.应用水质理化指标、污染指示种和污染指示群落评价童庄河水质,显示其水质为Ⅴ类,为β-中污型水体. 相似文献
5.
Mobility of lowland stream Trichoptera under experimental habitat and flow conditions 总被引：1，自引：0，他引：1
Piet F.M. Verdonschot Anna A. Besse-LototskayaDorine B.M. Dekkers Ralf C.M. Verdonschot 《Limnologica》2012,42(3):227-234
The species-specific mobility of six species of lowland stream Trichoptera was studied in flume experiments with different habitats and current flows. The test species were selected according to their occurrence along the environmental gradient from more natural towards highly disturbed sandy, lowland streams of the North-West European plain. Two groups of species were distinguished, three species occurring more frequently towards the natural end versus three occurring more frequently towards the disturbed end of the stream disturbance gradient. Experiments were conducted in a temperature and light controlled environment in indoor, re-circulating, man-made stream channels with four replicate gutters each. The bottom of each gutter held ten trays filled with five selected habitat materials (two trays each), which provided refugia and food. Three flow treatments with constant current velocities of 10, 30, or 50 cm/s were applied. Movements were scored based on visual observations of the position of each individual at fixed time points. The first day after release, individuals moved around very actively; this ‘release effect’ was removed from further analyses. The trichopteran species occurring near the more natural end of the disturbance gradient exhibited significantly less mobility (on average 10-15% of individuals actively moved around) than the species from the more disturbed end of the gradient (on average 30-40% of individuals actively moved around). The first group of trichopteran species also spent significantly longer times in the leaves habitat compared to the other three species, which moved more or less independent of habitat. With increasing current velocity, all test species moved more frequently, particularly the species from the more disturbed end of the gradient. This could indicate behavior to avoid dislodgement. The mobility of all species exceeded the mobility needed to use habitat resources of food and shelter, both present in excess. Therefore, short-term movement could also be (partly) a random behavior. Overall, the more tolerant species from the disturbed end of the gradient showed more mobility and flexibility than the species occurring under more or less natural stream conditions. This was consistent with the hypothesis that mobility is an adaptation of tolerant, ubiquitous species. Mobility is an adaptation of r-strategists. 相似文献
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Jørgen Kristiansen 《Aquatic Sciences - Research Across Boundaries》1978,40(2):310-319
In the Synuraceae, the silica scales which cover the cell surface are of great taxonomic importance, although their delicate structure requires use of electron microscopy. Many species have been incompletely described by means of light microscopy, and there are serious difficulties in correlating them with species based on electron microscopy of the silica scales. The different types of variation in scale structure are described, and the variation range to be accepted within a species is discussed. However, as sexual reproduction is of rare occurrence in this family, the species concept must be highly arbitrary. It is reassuring then that many species based on scale ultrastructure also exhibit morphological and ecological characteristics. The advantages of scanning and transmission electron microscopy are emphasized for species identification and for detection of small forms with especially delicate scales. 相似文献
8.
SHI Yukun & YANG Xiangning Department of Earth Sciences Nanjing University Nanjing China 《中国科学D辑(英文版)》2005,48(7)
Regional stratigraphic data of major fossil groups in the critical geologic periods could provide reliable materials not only for the studies of diversity changes in different biogeographic provinces,but also for the comparison of regional patterns in the major biotic events accumulated in a long history of investigation,the paleontologic and stratigraphic data of South China have made indispensable contributions to re-vealing the pattern of end-Permian extinction[1―3],analyzing the differenc… 相似文献
9.
The pelagic ciliate communities from 58 north German lakes differing in their origin (natural lakes and artificial ponds), morphology (from shallow ponds with a maximum depth of below 0.5 m to relatively deep lakes with a maximum depth of more than 10 m, surface areas from below 10 ha to more than 100 ha), trophic state (from mesotrophic to hypertrophic) and salinity (freshwater lakes and brackish water lakes) are described and compared at species level. Each lake was comprehensively sampled quarterly in the years 1996 and 1997, respectively. Applying a quantitative protargol stain, about 140 ciliate species could be identified and quantified in all investigated lakes. 35 species, mainly members of the Prostomatida and Oligotrichida, were found commonly in all types of lakes at all seasons and dominated the pelagic ciliate communities. 3 species were common in freshwaters, but never occurred in brackish lakes. In the brackish waters a mixture of common freshwater species and marine species was found with 13 species exclusively occurring in brackish waters. Lowest ciliate cell numbers were observed for deep freshwater lakes, highest cell numbers were determined for brackish waters. Highest species richness was found in artificial peat ponds with an average of 24 pelagic ciliate species in spring samples. The range of occurrence for the identified species was wide for most common species. However, the influence of some environmental factors could be enlightened. 相似文献
10.
东营凹陷古近系古湖盆演化与水化学场响应 总被引：12，自引：2，他引：10
采用人工配制污水为实验用水进行室内水培实验,研究10种人工湿地中常见水生植物对氨氮和总磷的同化吸收能力,筛选出净化效果好的植物,构建植物组合,以单一植物为对照,研究植物组合对于提高氨氮、总磷净化效果的作用．结果表明：不同植物对氨氮、总磷的去除能力差别较大千屈菜（Lythrum salicaria）、菖蒲（Acorus calamus）、美人蕉（Cannindica）、达香蒲（Typha davidiana）对氨氮净化效果较好,初始浓度2969mg／L、15d后,去除率966％、98．6％、877％、95．1％美人蕉、凤眼莲（Eichhornia crssipes）、干屈菜、石菖蒲（Acorus tartarinowii）对TP净化效果较好,初始浓度4．44mg／L、15d后,去除率99．0％、546％、69．9％、36．7％千屈菜与石菖蒲的组合能同时提高氨氮与总磷的净化效果;美人蕉与干屈菜的组合、菖蒲与美人蕉的组合、菖蒲与千屈菜的组合、美人蕉与石菖蒲的组合能提高总磷的净化效果组合实验结果表明,适当的水生植物组合能提高氨氮与总磷的净化效果。 相似文献
11.
山西晋阳湖浮游藻类分布的时空格局及水质分析 总被引：6，自引：2，他引：4
对山西晋阳湖的浮游藻类进行了研究,共发现156种及11变种,隶属于5门,25科,67属.其中以绿藻门种类最多,达29属57种4变种;硅藻门次之,17属34种6变种;蓝藻门和裸藻门分别为15属32种1变种和5属31种,黄藻门最少,只有1属2种.秋季浮游藻类种类最多,冬季最少.浮游藻类细胞密度变化范围为2.84×10~6-2.30×10~9 cells/L,平均细胞密度为4.86×10~8 cells/L.每个季节水体的浮游植物细胞密度均已达到富营养化水平.多样性指数、均匀度指数均较低,而优势度很高,说明水体处于富营养状态,污染严重. 相似文献
12.
Species diversity and distribution for phytoplankton of the Pearl River estuary during rainy and dry seasons 总被引：11，自引：0，他引：11
Huang L Jian W Song X Huang X Liu S Qian P Yin K Wu M 《Marine pollution bulletin》2004,49(7-8):588-596
Based on data collected at 31 stations and 1 continuous station in the Pearl River estuary during cruises of July 1999 (rainy season) and January 2001 (dry season), this study examined taxonomic composition, abundance, and spatial distribution of phytoplankton. Results indicated 130 species of phytoplankton in the samples from the rainy season, and 132 species in the dry season. Among them, in the rainy season, 82 species of diatom, 39 fresh-water and half-fresh-water species and 41 species of red tide organisms were found. Within these, there were 54 tropical and sub-tropical species, 47 cosmopolitan species and 17 temperate species. The abundance of phytoplankton in the rainy season was higher than that of the dry season, with an average of 6.3 x 10(5) cells x L(-1) and 1.4 x 10(5) cells x L(-1), respectively. Diversity index (H') and evenness (J) were 2.47 and 0.57 in the rainy season, and 2.01 and 0.54 in the dry season. The dominant phytoplankton species in the rainy season was Skeletonema costatum with an average of 2.8 x 10(5) cells x L(-1) and 45.0% of the total phytoplankton abundance. In the dry season, Eucampia zoodiacus became the key dominant species (5.9 x 10(4) cells x L(-1)) when it was 43.47% of the total phytoplankton abundance. Distribution of the dominant species varied with salinity of sea-water, and their amounts correlated negatively with nutrients and zooplankton. 相似文献
13.
2003年6月至2004年6月,对汉江流域上游支流--黑竹冲河的大型底栖动物群落结构与生物多样性进行了深入研究,结果表明:河流生物群落结构和生物多样性比较复杂,河流功能状况良好.在采集到的85种大型底栖动物中,昆虫占71种;群落表现出明显的时空特点,具边缘效应的第4采样点物种最丰富,2月份物种最多,达50种;生物多样性指数周年动态显示,第1采样点的物种多样性变动最为平稳,第5采样点变动最大,其它各点居中;各微生境中共有种占据优势,物种相似性均大于60%;群落春季的多样性高于夏季,夏季高于秋季;功能摄食群则以收集者占优,共计达68种.群落密度在1月份达到最大,为1843 ind/m2;而生物量则在10月份达到最大,为228.7393 g/m2. 相似文献
14.
广东省水库枝角类组成特征的初步研究 总被引：4，自引：2，他引：2
于2000年丰水期和枯水期调查了广东省19座典型大中型水库枝角类,随后对其中3座代表性水库进行了4年的枝角类种类定性调查.在鉴定出的枝角类16属24种中有13个广温种、7个嗜暖种、3个嗜寒种和1个特有种;每个水库的平均种类数5-6种.从个体大小来看,水库枝角类以小个体种类为主,有14种的体长小、于1 mm,它们分布广且数量多,其中优势种主要为长额象鼻溞、秀体溞、微型裸腹溞、颈沟基合溞和角突网纹溞等.透明溞和透明薄皮溞是主要的大个体种类,出现在4座贫、中营养水库的水样中.水库枝角类的丰度较低,在丰水期,平均丰度小于10 ind./L和10-20 ind./L的水库分别为14座和5座,在枯水期,为12座和5座,而高州水库和河溪水库中的平均丰度达67ind./L.主要优势种在不同营养类型水库中分布差别不大.枝角类的丰度受水力滞留时间影响,直流型水库的枝角类种群丰度的分布明显受到水流速度的影响,湖泊区枝角类个体及其食物均随水库放水输出而减少.由于采样点主要位于大坝附近,枝角类以敞水区的种类为主.从种类组成和数量来看,广东省水库枝角类具有明显的热带特点,枝角类的生物量小,以个体较小的种类优势种,大型种类的个体数量极低且身体透明. 相似文献
15.
The quantitative and qualitative relationships within phyto- and zooplanktonic communities were examined for a period of one year in a small eutrophic lake in Udaipur, through the application of diversity indices. The results revealed that a higher plankton diversity needs not necessarily lead to a greater community diversity or evenness of species diversity. The phytoplankton species diversity was related to nutrients and ambient environmental factors. Within zooplankton groups, the diversity index was found influenced by the evenness and richness of the species. On the other hand, the strong correlation between individual species density and community diversity in the cladocera was influenced by food availability. The total zooplankton diversity was also strongly correlated (P < 0.01) with the number of species and equality. There was no spatial variation in species composition because of smaller spread of the water body. It is felt that the diversity indices could get influenced by the dominance or scarcity of one or more species or communities giving a deceptive picture of planktonic panorama. 相似文献
16.
The photosynthetic rates of five phytoplankton species were inhibited following treatment with the water-soluble fractions (WSF) of used lubricating oil. Exhaust oil from an outboard motor inhibited photosynthesis in three out of the five species tested which indicates a species specific response in the case of this form of oil pollution. Water-soluble fractions from Qatar crude had no inhibitory effect on any of the species tested but had a stimulatory effect on the photosynthetic rate of one species. Both oxygen evolution and carbon assimilation were inhibited by the water-soluble fraction of used lubricating oil. In four out of five species, used lubricating oil WSF caused a net oxygen consumption during the light phase rather than a net oxygen release. These data indicate that used lubricating oil water-soluble fractions are especially toxic to phytoplankton. 相似文献
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由于自然和人为因素的影响,三峡水库鱼类资源一直在发生变化,为掌握三峡水库蓄水后典型支流香溪河鱼类群落的现状及历史变化,于2020年7月—2021年4月使用多网目复合刺网和地笼对香溪河鱼类群落进行实地采样,并结合历史数据进行比较分析。研究期间共采集到鱼类55种,隶属于7目14科,鲤科鱼类种类数最多,以杂食性鱼类和湖泊定居性鱼类为主,优势种为贝氏?(Hemiculter bleekeri)、短颌鲚(Coilia bratchygnahus)、似鳊(Pseudobrama simoni)和翘嘴鲌(Culter alburnus),其相对重要性指数(IRI)分别为5502、3828、2567和1109。鱼类物种多样性指数在春季最高,夏季最低。刺网单位捕捞努力量渔获个体数和单位捕捞努力量渔获量在夏季最高,冬季最低。与三峡水库蓄水前相比,香溪河鱼类中长江上游特有鱼类减少4种,外来鱼类增加3种。湖泊定居性种类持续增加,喜流水性种类减少,鱼类优势种发生较大变动。2020—2021年香溪河鱼类组成与1987年的相似性指数为0.29,与2012—2013年的相似性指数为0.53,反映三峡水库蓄水前后香溪河... 相似文献
19.
The distribution of aquatic Heteroptera (Corixidae and Gerromorpha) in three backwater systems of the Austrian Alluvial Forest National Park differing in connectivity to the Danube River was examined at 44 locations between 1999 and 2003. The most common species were Aquarius paludum and Gerris lacustris (Gerridae).Various statistical analyses were used to define the relationship between species occurrence and 15 environmental variables and to test their influences on species distribution. Canonical correspondence analysis suggested that the main environmental gradients were the transitions from water surface richly covered with branches and Lemna and vegetated shoreline, which most species preferred, to open habitats with little shoreline vegetation, which only a few species preferred.This study shows the potential significance of heteropterans as indicator groups for paleopotamic conditions and aquatic habitats with strong terrestrialisation processes. 相似文献
20.
四种浮游植物生物量计算方法的比较分析 总被引：4，自引：2，他引：2
浮游植物是水生生态系统中重要的初级生产者,其生物量是反映其现存量的关键指标.本文利用具有3个处理组的围隔实验中的浮游植物数据,对文献中常见的计算浮游植物种群生物量和群落生物量的4种方法:标准法、细分法、粗分法和资料法进行比较,并分析采用这4种不同方法得到的浮游植物生物量与叶绿素a浓度的相关性.结果表明:粗分法是计算浮游植物生物量的高效方法,能够保证准确度和节省时间;提高浮游植物生物量计算准确度不是影响浮游植物生物量与叶绿素a浓度相关性显著程度的关键.通过比较剔除稀有种(生物量不超过群落生物量5%的种类)前后浮游植物生物量的差异,发现忽略稀有种会导致种类均匀度较高的浮游植物群落生物量严重偏低,建议浮游植物生物量的计算不能一概忽略稀有种. 相似文献