Rotifer Community Structure Research Articles

流溪河水库敞水区轮虫多样性与群落的动态特征

PDF HTML阅读 XML下载 导出引用 引用提醒 流溪河水库敞水区轮虫多样性与群落的动态特征 DOI: 10.5846/stxb201605060873 作者: 作者单位: 暨南大学生态学系,暨南大学生态学系,暨南大学生态学系,暨南大学生态学系 作者简介: 通讯作者: 中图分类号: 基金项目: 广东省水利科技创新资助项目（2012-10）；国家自然科学基金资助项目（41573062） Rotifer species diversity and community structure in the pelagic zone of the Liuxihe Reservoir Author: Affiliation: Department of Ecology, Jinan University,Department of Ecology, Jinan University,Department of Ecology, Jinan University,Department of Ecology, Jinan University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:流溪河水库是位于北回归线上的大型峡谷型供水水库，于2013-2014年对该水库敞水区轮虫群落及其环境因子进行观测，分析敞水区轮虫多样性与群落动态特征。流溪河水库介于贫营养到中营养水平之间，丰水期（5月-9月）的总磷、透明度均高于枯水期（10月-4月），两年的总磷的平均值为0.019mg/L，透明度为2.55m。两年共检出轮虫40种，单月检出物种数波动范围为8-19种，月均检出轮虫13种。螺形龟甲轮虫、真翅多肢轮虫、沟痕泡轮虫和胶鞘轮虫是主要优势轮虫。2013、2014年轮虫年均总丰度分别为68.9、66.9个/L，两年物种丰富度在丰水期大于枯水期，但枯水期轮虫群落Simpson多样性指数均大于丰水期。采用Bray-Curtis距离测度群落之间的相异性，计算表明两年的枯水期轮虫群落之间的平均距离均大于丰水期，即丰水期时轮虫群落相似性较高，枯水期时轮虫群落变异较大。丰水期的水温和水质参数的变化相对稳定，种类的优势度更为明显，导致丰水期群落之间更为相似。主成分分析表明，无柄轮属、胶鞘轮属、多肢轮属、异尾轮属、泡轮属、晶囊轮属和皱甲轮属的主要种类的全年分布有较大的差异，而其余多数轮虫种类全年分布差异较小，反映了我国南亚热带地区水温全年变幅小，可维持较多的全年性种类共存。群落的方差解析与RDA分析表明，相对于生物与化学变量，物理环境变量主导了流溪河水库敞水区轮虫群落的变异，就单个变量而言，水温和食物是影响流溪河水库敞水区轮虫群落结构的重要因素，降雨则是影响轮虫群落结构变异的宏观因素。绝大多数轮虫为滤食性的，处于食物链底端，个体小、生活史短，轮虫群落在对环境因子变化的响应上与浮游植物具有相似性。 Abstract:The Liuxihe Reservoir is a large canyon reservoir located on the Tropic of Cancer in Guangdong Province, and is used as a source of drinking water. The diversity and dynamics of rotifer species as an indicator group of water quality and ecosystem health, and environmental variables were investigated monthly in the pelagic zone of the reservoir from 2013 to 2014. We used the R language program (MASS, vegan, and packfor packages) to analyze the species diversity and community structure of rotifers in the pelagic zone of Liuxihe Reservoir. The rotifer community structure was analyzed using principal component analysis (PCA), redundancy analysis (RDA), nonmetric multidimensional scaling (NMDS), and variation partitioning. In the present study, Liuxihe Reservoir is an oligotrophic or mesotrophic water body, with annual averages of total phosphorus of 0.019 mg/L and water transparency of 2.55 m. Both total phosphorus and water transparency were slightly higher in the wet seasons from May to September than dry seasons (October to April). In total, 40 species were observed during the two-year investigation. The observed species richness ranged from 8 to 19 monthly, with a monthly average of 13. Keratella cochlearis, Polyarthra euryptera, Pompholyx sulcata, and Collotheca sp. were the dominant species. The average total abundance was 68.9 and 66.9 individuals/L in 2013 and 2014, respectively. The species richness was higher in wet than in dry seasons, whereas the Simpson index showed the opposite pattern. The average community distance, which was measured by the Bray-Curtis distance, was higher in dry than wet seasons, indicating that the rotifer community similarity was higher in wet than dry seasons. Water temperature and other variables of water quality were more stable in wet seasons. As a result, species dominance became stronger and rotifer communities were more similar. PCA indicated that Ascomorpha, Collotheca, Polyarthra, Trichocerca, Pompholyx, Asplanchna, and Ploesoma species showed significant temporal variation. This rotifer community structure is representative of tropical and subtropical China, where there is less water temperature fluctuation, allowing more species to occur throughout the year. Variation partitioning and RDA of the rotifer community with environment variables demonstrated that physical environment variables including temperature, dissolved oxygen, Secchi disk depth, precipitation, and water retention time explained the variance of the rotifer community, and among all the measured variables, water temperature and food availability were the two key factors explaining community structure variation, and precipitation was a macroscopic indirect factor affecting the variation of rotifer community. Most rotifer species are filters at low tropic levels in the pelagic zone of the Liuxihe Reservoir, with a small body size and short life span, and their communities responded to the variation of environmental factors similarly to phytoplankton communities. 参考文献 相似文献 引证文献

Spatial and temporal variation in rotifer community structure and the response to environmental factors among different water bodies in Guangzhou City

轮虫是水体中重要的浮游生物类群，对环境变化敏感，是水生态系统中食物链及微型食物网的关键环节.于2015年夏季（7月）和冬季（12月）对养殖池塘、水库、广州城市湖泊、珠江河口及珠江河段水域的轮虫和理化环境指标进行了调查分析，共发现轮虫26属、76种，其中裂痕龟纹轮虫（Anuraeopsis fissa）在7月河流水体占绝对优势，但12月数量明显减少.冬季珠江河段和河口水体群落多样性指数与均匀度指数较夏季高，群落结构较夏季稳定.调查水体轮虫丰度范围为33~2625 ind./L，城市湖泊夏季丰度较高，冬季有所下降，而养殖池塘轮虫丰度在冬季有所上升.群落结构相似性分析（ANOSIM）分析表明，不同类型水体之间差异显著，尤以湖泊与河流差异性最大，广布多肢轮虫（Polyarthra vulgaris）在湖泊贡献率最高，暗小异尾轮虫（Trichocerca pusilla）其次；裂痕龟纹轮虫在河流贡献率最高，优势种丰度差异是造成湖泊与河流群落结构差异的主要原因.统计分析表明，轮虫丰度与叶绿素a浓度呈正相关.冗余分析与ANOSIM分析发现广布多肢轮虫在流花湖等叶绿素a浓度较高的静态水体中易形成优势；裂痕龟纹轮虫和角突臂尾轮虫（Brachionus angularis）在珠江河段等总氮和总磷浓度高的富营养化流动水体中易形成优势.综合轮虫群落结构和水质特征，广州市水体富营养化严重，耐污性轮虫种类多，应加强城市水生态系统保护和管理.;Rotifers, a kind of essential plankton in aquatic ecosystem, is sensitive to environmental changes and playes an important role in food chain and microbial foodweb. Environmental factors and rotifer samples were collected from five type of water bodies (lake, pond, river, reservoir and estuary) in July and December, 2015, Guangzhou City. A total of 76 specie was identified, which belonging to 26 genera. The dominant species were Anuraeopsis fissa, in river in July and decreasing in December. The evenness index and the diversity index of river and estuary in winter were much higher than those in summer. Rotifer abundance ranged from 33 to 2625 ind./L. The abundances of rotifer in city lakes in summer were higher than those in winter, while opposite situation for the ponds. Analysis of similarities(ANOSIM) determined that the community structure was significant different among the different water bodies. These differences came from the abundance of dominant species, especially the river and lakes. Owing to the largest contribution rate of lakes made by Polyarthra vulgaris and that of river made by Trichocerca pusilla and A. fissa, the community structure of rotifers was significantly different. Statistical analysis showed that there was a positive correlation between chlorophyll-a concentrations and rotifer abundance. Redundancy analysis and ANOSIM analysis represented that P. vulgaris was more likely to dominated in lentic water, such as Lake Liuhua which contented of high chlorophyll-a concentration. A. fissa and Brachionus angularis were dominant in the Guangzhou segment of the Pearl River, the lotic waters with high total nitrogen and total phosphorus concentrations. In summary, the waters in Guangzhou City were eutrophic and measures should be taken to protect urban aquatic ecosystem.

汀棠湖轮虫主要食性功能群及其优势种群的周年动态对水环境变化的响应

PDF HTML阅读 XML下载 导出引用 引用提醒 汀棠湖轮虫主要食性功能群及其优势种群的周年动态对水环境变化的响应 DOI: 10.5846/stxb201610232158 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金（31470015）；安徽省高校自然科学研究重点项目（KJ2017A320）；重要生物资源的保护与利用安徽省重点实验室专项基金 Reponses of the annual dynamics of functional feeding groups and dominant populations of rotifers to environmental factors in Lake Tingtang Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为探讨轻度富营养湖泊中轮虫主要食性功能群及其优势种群的动态对水环境响应的生态机理，于2011年7月至2012年6月每月4次采集了芜湖市汀棠湖水体中的浮游动物样品，同步测定了水温、水体透明度、pH值、水体叶绿素a含量和氮磷含量，利用相关分析和多元线性回归分析方法分析了轮虫主要食性功能群及其优势种群的密度与非生物因子（如水温等）、食物资源（以粒径大小不同的藻类中的叶绿素a含量作为指标）及生物因子（枝角类、桡足类和晶囊轮虫等轮虫潜在竞争者和捕食者的密度）间的关系。结果显示：（1）汀棠湖中，掠食性轮虫的优势轮虫为针簇多肢轮虫（Polyarthra trigla）；滤食性轮虫的优势种包括裂足臂尾轮虫（Brachionus diversicornis）、长三肢轮虫（Filinia longiseta）和裂痕龟纹轮虫（Anuraeopsis fissa）；（2）主成分分析表明，水温、叶绿素a含量、枝角类、桡足类及其无节幼体和晶囊轮虫的密度是影响与汀塘湖轮虫群落结构有关的变动最大的水环境因子。水温和藻类叶绿素a总含量分别对滤食性轮虫和掠食性轮虫总密度的周年变动的影响最大，而轮虫的潜在竞争者和捕食者对它们的负面影响均不大；（3）轮虫的潜在竞争者和捕食者对于轮虫优势种群密度动态的负面影响也不大。水温、藻类叶绿素a总含量及小型藻类叶绿素a含量（经孔径为25 μm的筛绢过滤后水样中的叶绿素a含量（Chl-a < 25 μm））均与滤食性裂足臂尾轮虫和长三肢轮虫的密度间呈现显著或极显著的正相关关系。仅小型藻类的叶绿素a含量对裂足臂尾轮虫和长三肢轮虫密度的周年变动的影响最大。水温是影响滤食性裂痕龟纹轮虫密度动态的主要因子；（4）两食性功能群中的优势轮虫种群的卵率均未与其潜在竞争者和捕食者密度间呈现显著的负相关性。裂足臂尾轮虫、长三肢轮虫和针簇多肢轮虫种群卵率的变动受水温的影响最大，且它们之间均分别呈现显著的负相关性。研究结果表明，水温和食物资源可能是影响汀塘湖中滤食性轮虫和掠食性轮虫密度变动的重要的生态因子。 Abstract:To study the ecological mechanisms underlying the responses of the functional feeding groups and dominant populations of rotifers to environmental factors in a slightly eutrophic lake, zooplankton samples were collected once weekly during July 2011 and June 2012 from Lake Tingtang, located in Wuhu City, Anhui Province, China. We also identified and analyzed annual variations in the density of each functional feeding group, the dominant populations, and the egg ratios of the dominant populations of rotifers. Simultaneously, physicochemical variables of water samples collected from Lake Tingtang, including water temperature, chlorophyll a (Chl-a) concentration, transparency, pH value, TN, NO3--N, NH4+-N, TP, and PO43- were measured. The Chl-a concentration in each water sample was measured in two fractions:one filtered through a 25 μm plankton net (Chl-a < 25 μm) and another unfiltered (Chl-a), which were used as biomass indicators of the algae with a smaller volume and all phytoplankton, respectively. On the basis of Pearson correlation and multiple linear regression analyses, the relationships between the densities of each rotifer functional group and dominant population and each of the environmental factors (abiotic factors, such as water temperature, food resources measured by the Chl-a concentrations of the algae with different cell volumes, and biotic variables of potential competitors, such as cladocerans and predators, including copepods and carnivorous Asplanchna rotifers) were analyzed. The main results were as follows. (1) Among the four dominant rotifer species occurring in Lake Tingtang, Polyarthra trigla was considered as a raptorial species, whereas Brachionus diversicornis, Anuraeopsis fissa, and Filinia longiseta were classed together as filter-feeding species. Suckers such as Trichocerca spp. were not considered in the present study because of their extremely low density. (2) Principal component analysis (PCA) showed that water temperature, Chl-a concentration, the densities of cladocerans, copepods and their nauplii, and Asplanchna were crucial for determining the dynamics of rotifer community structure in Lake Tingtang. Water temperature and Chl-a concentration of all phytoplankton was the most important factor shaping the annual dynamics of the filter-feeding and raptorial rotifers in Lake Tingtang, respectively. However, interspecific competition and predation pressure were not the key factors controlling the seasonal dynamics of any functional feeding groups. (3) Interspecific competition and predation pressure were also not the key factors affecting the annual dynamics of dominant populations of filter-feeders. Water temperature and the Chl-a concentration of algae with a smaller volume (Chl-a < 25 μm) were positively correlated with the densities of B. diversicornis and F. longiseta, classified as filter-feeders. Furthermore, the seasonal dynamics of B. diversicornis and F. longiseta were principally controlled by Chl-a < 25 μm. In comparison, the density of A. fissa was only affected by water temperature. (4) The egg ratios of filter-feeding rotifers, including B. diversicornis and F. longiseta, and the raptorial species P. trigla were mostly influenced by water temperature. Additionally, the egg ratios of three rotifers decreased with a decrease in water temperature. Taken together, the results indicate that water temperature and food resources are more likely to be the key factors affecting the annual dynamics of filter-feeding and raptorial rotifers than are the other examined variables, such as interspecific competition and predation pressure. 参考文献 相似文献 引证文献

Seasonal variability in the structure and functional diversity of psammic rotifer communities: role of environmental parameters

Data on the variability in structure and functioning of interstitial rotifer assemblages are rare; however, this knowledge is essential for understanding their role in the interstitial food web. In the present study, we characterized psammic rotifer communities in terms of dominance structure, trophic traits, taxonomic and functional diversity at a seasonal scale in freshwater lakes across Estonia and coastal beaches of the Baltic Sea. A total of 42 rotifer species were found from the coastal beaches and 66 species from the lakes. Functional indices did not exhibit smaller seasonal variability and neither did they respond better to changes in the environment compared to taxonomic indices. However, there were differences how environmental variables affected these two broad groups of response variables. The taxonomy-based indices of rotifer communities were primarily driven by seasonal temperature regime, sediment characteristics and anthropogenic stressors, whereas the trait-based indices were a function of ecosystem types (freshwater or brackish water). The functional indices of the psammic rotifer communities strongly distinguished between freshwater and brackish habitats indicating that rotifers have different functional roles in food webs in fresh and brackish water environments.

Determinants of community structure of zooplankton in heavily polluted river ecosystems.

River ecosystems are among the most affected habitats globally by human activities, such as the release of chemical pollutants. However, it remains largely unknown how and to what extent many communities such as zooplankton are affected by these environmental stressors in river ecosystems. Here, we aim to determine major factors responsible for shaping community structure of zooplankton in heavily polluted river ecosystems. Specially, we use rotifers in the Haihe River Basin (HRB) in North China as a case study to test the hypothesis that species sorting (i.e. species are “filtered” by environmental factors and occur at environmental suitable sites) plays a key role in determining community structure at the basin level. Based on an analysis of 94 sites across the plain region of HRB, we found evidence that both local and regional factors could affect rotifer community structure. Interestingly, further analyses indicated that local factors played a more important role in determining community structure. Thus, our results support the species sorting hypothesis in highly polluted rivers, suggesting that local environmental constraints, such as environmental pollution caused by human activities, can be stronger than dispersal limitation caused by regional factors to shape local community structure of zooplankton at the basin level.

Temporal and spatial variations in rotifer correlations with environmental factors in Shengjin Lake, China.

Shengjin Lake is an important wintering and stopover habitat for migratory birds en route from East Asia to Australia. The authors investigated the rotifer community structure and environmental factors in upper Shengjin Lake from February to July of 2014. A total of 17 genera and 31 species of rotifers were identified, the dominant species being Brachionus angularis, Brachionus calyciflorus, Asplanchna priodonta, and Schizocerca diversicornis. Rotifer density and the nutrient salt content were higher in the areas inhabited by migratory birds. The highest density (176.0ind./L) was recorded in June, the lowest (14.0ind./L) in April. Canonical correspondence analysis (CCA) and correlation analysis showed that some environmental factors, such as temperature, pH, water depth, Secchi depth (SD), and chlorophyll a concentration, had a considerable effect on the lake's rotifer community structure.

&lt;b&gt;Rotifer community structure along a stretch under the influence of dams in the Upper Paraná River floodplain

The construction of reservoirs imposes substantial impact on freshwater ecosystems and changes the ecological aspects of the lotic system downstream of dams. We hypothesized an increasing dissimilarity between communities in the sampling sites according to increasing distance from the Porto Primavera Dam. In addition, we expect that the rotifer community in the last sampling site will be influenced more by environmental variables related to trophic status. Samplings were conducted under the water surface of ten sites on the Parana River in August 2013. Environmental variables were also determined. The highest number of taxa belonged to families Brachionidae, Lecanidae and Trichocercidae. The most abundant species was observed to Synchaeta oblonga, Keratella cochlearis, Brachionus calyciflorus. The species dissimilarity between sampling sites, tested using the Sorensen index, showed high dissimilarity between sampling sites. Redundancy analysis indicated a significant relationship between environmental variables (total phosphorus and ammonia) and abundance of Brachionus calyciflorus and Keratella cochlearis, in the last sampling site. Our results suggest a greater dissimilarity between the rotifer communities according to increasing distance from the Porto Primavera Dam. In addition, a higher influence of the environmental variables related to trophic conditions was observed in the last sampling site, and influenced indirectly the occurrence and abundance of some rotifer species, due to increased availability of food resources, confirming the predicted hypothesis.

Response of rotifer community to environmental changes in five shallow lakes in the middle reach of Changjiang River, China

We evaluated the response of a rotifer community to environmental changes in five shallow lakes in the middle reach of the Changjiang (Yangtze) River in summer and autumn 2010. These five lakes differed in trophic status and rotifer community structure. Twenty-nine rotifer species were collected, of which Keratella cochlearis, Polyarthra dolichoptera, and Trichocerca elongate were dominant. The mean density, Shannon-Wiener diversity, and equitability among the five lakes differed significantly (P < 0.05). The mean rotifer density was positively correlated with trophic state. The diversity was higher in lakes with high macrophyte coverage. The composition of rotifer species was closely associated with the trophic gradient. Five environmental variables, Secchi depth, conductivity, TN, NH4-N, and TP, significantly affected the composition of rotifer species. Keratella quadrata, Brachionus calyciflorus, and B. forficula were more common in eutrophic conditions. Our results suggest that eutrophication has a significant influence on the rotifer community structure and highlight the potential for using rotifer community structure as an indicator of trophic status in subtropical lakes.

Distinct difference of littoral rotifer community structure in two mangrove wetlands of Qi'ao Island, Pearl River estuary, China

Less study was focused on the ecological community of littoral rotifers than on pelagic area worldwide. Moreover, rotifers were overlooked mostly due to the improper sampling methods and lack of experienced taxonomists for ecological researches, and the diversity and role of estuarine rotifers in ecological systems were underestimated severely. A long-term investigation of the littoral rotifer in a shallow mangrove swamp (MS) and a tidal creek (TC) of Qi'ao Island, the Pearl River estuary of southern China, revealed significant differences of the community structure at different sites and in different seasons. Ninety-four monogonont rotifers were detected in total. The average abundance of rotifer at MS (97.0 individuals/L) was lower than that at TC (140.8 individuals/L), but all average diversity indexes at MS were higher than those at TC. The main species at MS were Colurella sp.1, Encentrum marinum, Colurella adriatica, Synchaeta cf. kitina, Synchaeta sp., and Cephalodella cf. innersi, whereas they were Synchaeta cf. kitina and Brachionus angularis at TC. The rotifer community was correlated with the salinity and total nitrogen group most at MS, while temperature contributed most at TC. This study revealed higher diversity and abundance of littoral rotifers at the two close mangrove wetlands of Qi'ao Island compared to other studies. Different kinds of biotopes at the two sites displayed significant difference of the community structure, which was mainly due to the abundance of different main species present at the two sites. The peculiar environment of MS created an unusual rotifer community which had more marine species with higher abundance mostly in winter.

The trophic status of Suwałki Landscape Park lakes based on selected parameters (NE Poland)

This study describes changes in the trophic status of 12 lakes within Suwałki Landscape Park (SLP). All of the trophic classifications of the lakes were based on the trophic continuum division. Trophic status was determined by means of multiparameter indices using several diverse criteria. In this study, the assessment of the trophic status of lakes included water quality; abundance and biomass of bacterioplankton, phytoplankton, and zooplankton; and primary production of phytoplankton. The Carlson trophic state index (TSI) describes the level of water fertility and indicated the dominance of moderately eutrophic waters. Lakes Perty, Jeglówek, and Hańcza have a trophic status that indicates mesotrophy (TSI <50). The trophic status of the studied lakes was determined based on the bacterial abundance and clearly showed a lack of oligotrophic lakes in SLP. Based on the number of bacteria, only Lake Szurpiły can be classified as β-mesotrophic, whereas Lake Linówek can be characterized as hypertrophic with some features typical for humic waters. The greatest value of gross primary production was observed in Lake Linówek (126.4 mg C/m3/h). The phytoplankton trophy index varied from 1.59 to 2.28, and its highest value, which indicated eutrophy, was determined for Lake Udziejek. In the case of Lakes Hańcza, Szurpiły, Perty, Jeglówek, and Kojle, the index ranged from 1.25 to 1.74, which indicated mesotrophy. The majority of the lakes were classified as mesoeutrophic (1.75–2.24). The highest trophic status was assessed for lakes with a marked dominance of cyanobacteria (Lake Przechodnie, Lake Krajwelek, Lake Udziejek, and Lake Pogorzałek), which is commonly recognized as an indicator of high trophic status. Considering all of the indices of trophic status, the analysis of rotifer community structure indicates that the studied group of lakes is mesoeutrophic or eutrophic. The values of crustacean zooplankton indices indicated that the trophic status of the studied lakes was close to that determined using a TSI. The parameters of zooplankton abundance and species structure allowed for the observance of changes in the tropic levels of lakes, which are difficult to detect by a chemical assay alone.

The structure of psammic rotifer communities in two boreal lakes with different trophic conditions: Lake Võrtsjärv and Lake Saadjärv (Estonia)

Abstract Psammon communities are still poorly studied worldwide. The aim of the present study was to establish the structure of psammic rotifer communities including their diversity and quantitative parameters. A total of 41 rotifer taxa were found in hydro-, hygro-, and euarenal zones of eutrophic Lake Võrtsjärv and mesotrophic Lake Saadjärv during the study carried out in Estonia in 2008, including 11 rotifer species new to Estonia. In L. Võrtsjärv, the predominant rotifer taxa were Bdelloidea and Lecane psammophila. L. psammophila dominated in July and August and bdelloids prevailed in the rest of the year. In L. Saadjärv, the most abundant taxa were Lepadella ovalis, Keratella hiemalis, and Cephalodella megalocephala. The psammic rotifer community of L. Saadjärv proved to be more diverse than that of L. Võrtsjärv. Microphagous rotifers were dominant in L. Võrtsjärv. Raptorial feeders dominated in L. Saadjärv in summer and autumn and were more abundant at sites with coarser sand and low plant density.

Molecular phylogenies as a tool to understand diversity in rotifers

Over the past decade, the availability of DNA sequence data from rotifers and the development of statistical and analytical tools linked to phylogenetic reconstructions allowed researchers to deepen our knowledge of patterns and processes in rotifer diversity. Here, I review the recent rotifer literature regarding: (i) the position of rotifers in the animal kingdom, with the wide consensus being within Spiralia, in a clade called Platyzoa together with Acanthocephalans, Gastrotricha, Gnathostomulida, Micrognathozoa, and Platyhelminthes; (ii) the still unresolved phylogenetic relationships within rotifers and the disputed position of Acanthocephala; (iii) the discovery of extensive hidden diversity through DNA taxonomy; (iv) phylogeography; and (v) the phylogenetic structure of rotifer communities. In order to facilitate the further discovery of hidden diversity in rotifers, I provide a simple tutorial on the currently available methods in DNA taxonomy from single locus data using a previously published rotifer dataset as an example. Moreover, I outline a brief perspective on the potentiality of the use of phylogenetic approaches in future rotifer studies.

The rotifer community and its functional role in lakes of a neotropical floodplain

Aquatic communities vary depending on local factors, such as environmental conditions and biological interactions and regional factors, such as the hydrological regime in floodplains. This study analyzed the community structure of rotifers and their secondary production in two lakes of an Upper Paraná River floodplain (Brazil) differing in their hydrology: one connected to the river and the other isolated. Integrated samples of the water column were collected daily during 15 days in the low and high water periods. Three statistical methods, ANOVA, MRT, and IndVal were applied to distinguish the structure, biomass, and secondary production of their rotifer communities. The rotifer fauna was rich (91 species). Temperature, an indicator of seasonal change, and hydrological connection to river were major factors structuring rotifer communities. The community presented differences between periods in the isolated lake, but had a higher stability in the connected lake. We identified 34 indicator species of the groups formed by the MRT analysis. Production was low and consistent in the connected lake (∼1.5 µg DW m−3 day−1), being higher and more variable in the isolated lake (peaking at ca. 60–90 µg DW m−3 day−1). Results also showed that changing environmental conditions verified in the low water period and in the isolated lake were determinant for both the community structure and the secondary production of rotifers. We demonstrate that not only flooding but also the levels of isolation from the river during low water period are the driving forces for the structure and dynamics of organisms in floodplains. Thus, the isolated lakes represent important areas for rotifer biodiversity.

Habitat as the most important influencing factor for the rotifer community structure at landscape level

This study investigated the impact of several environmental parameters that structured the rotifer communities of 55 ponds within the Wielkopolska district of Poland, a rural landscape of ca. 30 000 km2. Habitat type was the strongest predictor of rotifer distribution, regardless of any other factors that we examined. Most rotifer species were associated with waterbodies dominated by macrophytes, thereby illustrating the value of examining vegetated zones, even in small ecosystems. Oxbow lakes were an important source of rotifer diversity and were found to be distinct from other small water bodies in the region. Two types of rotifer communities were distinguished based on origin of the water body. (1) Naturally occurring, post‐glacial, ponds that had been anthropogenically modified were characterized by relatively more pelagic species, greater total abundance, and higher numbers of eutrophic species. (2) Oxbows lakes and artificial ponds had greater species diversity and greater abundant occurrence of littoral rotifers.

Community structure of rotifers in relation to environmental factors in Lake Hongze

The spatial-temporal changes in rotifer species composition and community structure and their relationship with key environmental factors were investigated seasonally from May 2010( spring) to February 2011( winter) in a shallow freshwater lake,Lake Hongze,China.Totally 34 species of rotifer,belonging to 17 genera,were identified during the seasonal sampling.Keratella cochlearis,Asplanchna priodonta,Polyarthra dolichoptera,Brachionus calyciflorus and Keratella valga were the dominant species.Lake Hongze has three main areas that are Chengzihu,southwest and east area.The rotifer distribution in the three main areas was significantly different.There were 27,26 and 19 species in Chengzihu,southwest,east area,respectively.Meanwhile,the maximum density and biomass of rotifers was found in the southwest area of Lake Hongze while the minimum was found in the east area.In terms of seasonal variation,the density and biomass of rotifer was highest in spring,with higher values in autumn.The density and biomass in summer was lowest in the four seasons.Their relationship with environmental factors was analyzed using canonical correspondence analysis( CCA).From the result of CCA,environmental factors such as water temperature,dissolved oxygen and chlorophyll-a that representing seasonal variations of water quality were significantly correlated with the Axis 1 and affected the composition and the density of rotifer community.Moreover,environmental factors related to nutrient concentrations such as total phosphorus,total nitrogen and dissolved inorganic nitrogen were also important nutrient factors which influenced the community structure of rotifer of Lake Hongze.

Impact of river current on the uniformity of littoral communities of Rotifera

AbstractStudies were carried out in September 2007 at a set of stations called RIVERS located on two tributaries of the Narew River, and six stations on the tributaries of the Supraśl River. Concurrently, rotifers were sampled at nine stations of the River Rudnia (called RUDNIA). The aim of the research was the verification of the hypothesis on the uniforming effect of the river drift on rotifer communities inhabiting aquatic vegetation. The total numbers of all monogonont species inhabiting aquatic vegetation of RUDNIA and RIVERS were 83 and 107, respectively. The percentage similarity of rotifer communities from aquatic vegetation and river current at the same stations was relatively low and only slightly higher in RIVERS (21.7%) than RUDNIA (17.1%), which suggests that species composition of communities of epiphytic rotifer fauna has a rather low impact on species structure of rotifer communities in water drift. The set of individuals of different species carried with the water current was random and various at different stations. Although the percentage similarity of rotifer communities in the river drift calculated for all possible pairs of the stations was relatively lower in RIVERS than in RUDNIA, it was not reflected in the similarity of epiphytic rotifer communities, which were similar in both sets of stations. Thus, the hypothesis cannot be confirmed by the results of this research.

Relationship between environmental factors of the water and rotifer community structure in West Lake,Hangzhou

2007年1月-2010年10月,对杭州西湖进行调查研究,利用综合营养状态指数对西湖的营养状况进行评价,通过种类组成、优势种、多样性指数等指标探讨西湖轮虫的群落结构与水体营养状况之间的关系.结果表明,西湖总体处于中-富营养状态.调查期间共检出轮虫29种,以角突臂尾轮虫(Brachionus angularis)、螺形龟甲轮虫(Keratella cochlearis)等最为常见;总数量处于较低的水平,多样性水平不高;各采样点在不同年份表现出不同的季节变化规律.相关性分析结果表明,西湖轮虫密度与水温、TLI指数、总氮、高锰酸盐指数、透明度和pH值的相关性高度显著;Margalef多样性指数和Shan-non-Wiener多样性指数与水体环境因子表现出不同的相关性.研究发现,西湖轮虫结构不仅与水体的营养状况关系密切,还受引水过程引起的水动力学的影响,从引水入湖口到出水口存在一个以水动力学过程为主导的生态梯度.;In the present study we evaluated the trophic status of West Lake on basis of investigations from January of 2007 to October of 2010.According to the data associated with species composition,dominant species,density and diversity of rotifers,the relationships between rotifer community structure and eutrophication were evaluated.The result indicated that the water in West Lake had been in a state of eutrophication.The dominant rotifer species were Brachionus angularis and Keratella cochlearis in all 29 species.The amount and diversity of rotifer species are all low.Structures of rotifer community were different in seasons,years and locations.The correlation analysis showed that rotifer density was significantly correlated with water temperature,status of eutrophication, total nitrogen,SD,COD_Mn and pH,respectively.There were significant correlations between Shannon-Wiener diversity index and environmental factors,but only total-nitrogen had obvious correlation with Margalef diversity index.The study showed that there existed an ecological gradient of the community structure of rotifers between intake and outlet,which were influenced by hydrodynamics of water diversion system.

Spring rotifer community structure in the Alcantara River (Sicily, Italy), using different mesh size nets: relation to environmental factors

The present study focus on some aspects of zooplankton structure in the Alcantara River (Sicily, Italy), in relation to environmental factors. Zooplankton samplings were performed in spring in four sites, located from up- to downstream along the river course. Four low-flow velocity station points were chosen along a transversal river section in each site. Samples were taken from all station points in the four sites by two different mesh sizes (55 and 100 μm) rectangular nets. Rotifer abundances were an order of magnitude higher in 55 μm mesh size samples than in 100 μm mesh size ones. The two communities also resulted significantly different (ANOSIM test, ρ=0.212; P=0.1%). Generally, low abundances (from 3470±5133 to 422±474 ind.m−3) were explained by low chlorophyll a concentration and the high-flow regime of this river. Rotifer dominated the zooplankton community. Cladocerans, copepods and nauplii occurred with considerably lower abundances than rotifers. However, the relative contributions of these taxa to total abundances depended on the mesh sizes used. Euchlanis and Adineta genera exhibited the highest abundances in the rotifer assemblage. Conductivity alone or in association with temperature and dissolved oxygen was the most important environmental factor affecting rotifer community distribution. Cephalodella sp., Lepadella sp. and Trichotria pocillum showed a high positive relation to pico-plankton, showing this fraction as a possible rotifer food item. This paper demonstrated a higher efficiency of the finest net to characterize riverine zooplankton community that increases from up to downstream in terms of abundances and diversity.

Rotifer community structure and assessment of water quality in Yangcheng Lake

Rotifer community structure was investigated in Yangcheng Lake in 2008. Dominant species and species diversity indices were determined and QB/T was used to assess water quality. The annual average density and biomass of the rotifers in Yangcheng Lake was 2 894 ± 1 006 ind./L and 12.47 ± 10.28 mg/L, respectively. The highest densities were observed in the western portion of the lake in March, but the highest biomass occurred in inflowing creeks in September. Within a year of monitoring in Yangcheng Lake, 93 species were identified and the dominant species were found to be Polyarthra trigla, Brachionus angularis, Keratella cochlearis, Keratella valga, Brachionus calyciflorus, and Filinia major. Of the species recorded, 75 were pollution indicator species. Density and biomass exhibited significant positive correlations with water temperature (R = 0.209, P = 0.003; R = 0.446, P = 0.000), but the peak density showed two lags in response to chl a. According to the Jaccard similarity index (SJ), the greatest similarity among dominant species occurred between creeks and the eastern part of the lake. The annual average Shannon-Wiener diversity index H′, Margalef richness index D and Pielou evenness index J were 1.96 ± 0.34, 1.61 ± 0.50 and 0.77 ± 0.10, respectively. In all four areas of Yangcheng Lake, β-mesosaprobic species comprised the largest share of pollution indicator species. These data suggest that Yangcheng Lake is mesosaprobic.

Environmental Predictors of Rotifer Community Structure in Two Types of Small Water Bodies

AbstractThe species diversity and distribution of rotifers between different habitats (elodeids, helophytes and open water) of 34 field and 31 forest ponds, differing in regard to origin, size, depth, macrophyte cover, overshading and the presence of fish were examined (N = 381).197 taxa were found in both types of ponds with 32 species being rare, endangered or new to Polish fauna. The species composition and Shannon‐Wiener index distribution reflected heterogeinity of the habitats, while rotifer mean densities revealed a reverse pattern in both types of water bodies. The great variability of limnological features contributed to a lack of significant differences in rotifer abundance between both types of water bodies. Although some rotifers preferred one specific type of water body (forest vs. field), the type of habitat was a much stronger predictor of their distribution, which reflects a necessity to examine ponds in relation to their microhabitats created by various macrophytes. Rotifers revealed a strict division into two groups – of pelagic origin (e.g., Polyarthra vulgaris), which were attributed to the open water and helophytes, and of littoral origin (e.g., Lepadella patella), which were associated with elodeids, biomass of a plant habitat and a lack of fish. The selective choice of the most complex habitat (elodeids) by only littoral species suggests the weak impact of fish in the studied ponds and the most advantageous conditions for littoral rotifers among such a habitat. The first group comprised species characteristic of field ponds, while the second was characteristic of forest ponds. (© 2011 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)