Species richness and composition patterns of clitellate (Annelida) assemblages in the treeless spring fens: the effect of water chemistry and substrate

Spring fens are isolated treeless wetlands of a high conservation value. Their environmental conditions are strongly related to their groundwater chemistry, which controls species distribution within various groups of organisms. Clitellates, a dominant group of non-insect aquatic fauna, however, have never been studied in these habitats. It is unclear from previous studies to what extent the distribution of aquatic non-insect taxa reflects water chemistry rather than the substrate structure. We studied 34 spring fens sampled in 17 isolated sites in the Western Carpathian Mountains to determine mainly the effects of water chemistry and substrate structure on variation in species richness and composition of clitellate assemblages as examples of the non-insect fauna. A total of 34 taxa were found, with 3–15 taxa collected per sample. Species richness was negatively correlated with water mineral concentration measured as water electric conductivity (r = −0.57, P < 0.001) and positively with TOC (r = 0.60, P < 0.001). Surprisingly, the lowest number of taxa was found in calcareous fens and richness increased towards Sphagnum-fens. There was a species turnover related to changes in mineral richness and substrate characters. The main change of species composition was promoted by changes in substrate structure. The second gradient of species composition was linked with the amount of nutrients, moisture, and dominance of sphagna, and was associated with an increase of eurytopic species in fens with high nutrient availability. It was difficult to separate the effects of water chemistry and substrate on clitellate species distributions owing to the fact that variation in tufa precipitation and vegetation was driven by water chemistry changes. This study presented the first quantitative data on fen clitellate assemblages, which appear to have an unusual pattern of species richness. In contrast to plants and molluscs, calcareous fens appeared to be a harsh environment for clitellate species. Only few specialized species, mainly Trichodrilus strandi, were able to establish viable populations. The significant effect of water chemistry on clitellate distribution patterns raises questions about the direct influence of water chemistry on non-insect aquatic taxa, which have previously been considered to be mostly determined by substrate characteristics.     

The distribution of aquatic oligochaetes in brackish inland waters in the SW Netherlands

Macrobenthic fauna was sampled in inland waters with unstable environmental parameters in the SW Netherlands. The distribution of 23 species of aquatic oligochaetes was related to chlorinity. Oligochaetes and other macrofaunal taxa were grouped by cluster analysis. Brackish-marine oligochaetes appeared to have a similarly large tolerance for chlorinity variations, as is known for the better researched euryhaline macrofauna.Communication no. 221.     

18S rDNA phylogeny of Clitellata (Annelida)

The phylogeny of Clitellata was analysed using 18S rDNA sequences of a selection of species representing Hirudinida, Acanthobdellida, Branchiobdellida and 10 oligochaetous families. Eleven new 18S sequences of Capilloventridae (one), Haplotaxidae (one), Propappidae (one), Enchytraeidae (two), Lumbricidae (one), Almidae (one), Megascolecidae (two), Lumbriculidae (one), and Phreodrilidae (one) are reported and aligned together with corresponding sequences of 28 previously studied clitellate taxa. Twelve polychaete species were used as an outgroup. The analysis supports an earlier hypothesis based on morphological features that Capilloventridae represents a basal clade of Clitellata; in the 18S tree it shows a sister-group relationship to all other clitellates. The remaining clitellate taxa form a basal dichotomy, one clade containing Tubificidae (including the former 'Naididae'), Phreodrilidae, Haplotaxidae, and Propappidae, the other clade with two subgroups: (1) Lumbriculidae together with all leech-like taxa (Acanthobdellida, Branchiobdellida and Hirudinida), and (2) Enchytraeidae together with a monophyletic group of all earthworms included in the study (Lumbricidae, Almidae and Megascolecidae). These earthworms are members of the taxon Crassiclitellata, the monophyly of which is thus supported by the data. The tree also shows support for the hypothesis that the first clitellates were aquatic. The position of the single species representing Haplotaxidae is not as basal as could have been expected from earlier morphology-based conclusions about the ancestral status of this family. However, if Haplotaxidae is indeed a paraphyletic assemblage of relict taxa, a higher number of representatives will be needed to resolve its exact relationships with the other clitellates.     

Successional phases and species replacements in freshwater rock pools: towards a biological definition of ephemeral systems

1. In temporary aquatic habitats, time is probably the dominant environmental factor affecting community composition, mainly by setting constraints on colonization success and the replacement of taxa over time. The mechanism and effect of a decreasing inundation period on community development, mostly in terms of truncation, are still poorly documented. The permanent and ephemeral components of temporary communities are expected to be differently influenced by the degree of persistence of the habitat. 2. To study the effect of time on invertebrate community assembly and dynamics in a short duration type of temporary aquatic habitat, we monitored 16 ephemeral rock pools which persisted from less than a week to about 1 month at two rock pool sites in semi‐arid south‐eastern Botswana. Data were collected every 2 days during a full inundation cycle. 3. All communities were initially assembled by permanent residents recolonizing the habitat from egg banks and were later joined by actively dispersing ephemeral taxa. Species replacements only occurred in two pools. Concurrent with a decrease in the densities of Branchipodopsis wolfi, population sizes of Leberis sp. and Culicidae (Aedes sp. and Anopheles sp.) increased in these pools. Although it was possible to distinguish two successive phases at one rock pool site, community assembly was generally a gradual process determined by dispersal strategies of the inhabitants. Additional rains after initial filling triggered dispersal by ephemeral taxa, mainly Micronecta youngiana and Hydroglyphus infirmus, and positively influenced colonization success. 4. Decreasing persistence shortens community development down to a critical point below which lack of time eliminates the possibility of species replacement. Based on these findings, we define ephemeral waters as aquatic habitats lacking species replacements. Other temporary water types have a relatively longer persistence, permitting successional replacement of species.     

Perspectives for the use of diatom assemblages in the water management policy of Overijssel (The Netherlands)

Diatoms have been sampled in several types of water bodies in the province of Overijssel for a period of five years. Samples from 333 sites were examined both in spring and autumn. Extensive analysis of physico-chemical variables was carried out.Data were processed by multivariate analysis for detecting correlations between species and environmental factors. Both ordination and clustering techniques were used. Statistical tests were performed to evaluate environmental relationships.The main factors in this study appear to be pH, nutrient pollution (saprobity and trophic degree) and alkalinity. Within the group of waters which is not influenced by extreme conditions of pH or pollution, there is a discrepancy between waters with low and high alkalinity.The present study confirms that diatoms are useful indicators of pollution and pH, as well documented by several authors. Diatoms are also suitable as biological indicators for alkalinity at least on a regional scale. This offers possibilities for the use of diatoms in monitoring studies, especially in waters that are still under relatively low environmental stress. It also offers opportunities for setting ecological standards, based on the characteristics of non-polluted water bodies. This aspect will be of interest to the water management policy in the province of Overijssel.     

不同类型景观水体浮游动物群落差异及其影响因素

探明不同类型景观水体中环境敏感型浮游动物群落特征差异及影响因素对景观水体生物多样性维持和水生生态系统保护十分重要。于2014年5月在上海选取具代表性的8个景观水体共设置35个采样点进行浮游动物采样调查,并同步测定水体环境指标。本次调查采集并鉴定浮游动物40种,其中轮虫29种,枝角类7种,桡足类4种。基于浮游动物群落组成进行聚类分析,所有采样点聚为四种景观类型:天然湖泊(淀山湖)、人工湖泊(滴水湖)、AAAA级公园水体(共青森林公园和古猗园)和普通综合性公园水体(世纪公园、和平公园、长风公园和车镜公园)。两种公园水体浮游动物种类较为丰富,多样性较高,各自约有40%的种为生境特有种,而淀山湖特有种仅1种(为猛水蚤),滴水湖3种均为蛭态类。物种相似性方面,大型天然淀山湖与人工滴水湖相似性最高(37.5%),普通公园水体次之(33.3%),与AAAA公园水体相似度最低(20%)。后两者间的相似性较高(27.8%),且两者与滴水湖的相似度均较低(18.5%和12.0%)。四类水体仅有3个共有种/类群:角突臂尾轮虫(Brachionus angularis)、螺形龟甲轮虫(Keratella co...     

Tropical acid streams – the chironomid (Diptera) response in northern Australia

1. Chironomidae, sampled by interception of drifting cast pupal exuviae, responded to inputs of acid, heavy metal-rich waters in a seasonally flowing tropical stream in northern Australia.
2. Responses included gain of distinctive (indicative) taxa, loss of some species typical of pristine conditions, and increase in species richness.
3. Experimental manipulation (upstream diversion) of a mine adit entry showed that these responses were the result of change in water quality.
4. The higher species richness at low pH, which is contrary to temperate studies, may be explained by the large tropical (Australian and south-east Asian) pool of species tolerant of naturally occurring acidic aquatic habitats.
5. The structure and responses of the exuvial-assessed chironomid community matched long-term larval data.     

Tropical acid streams – the chironomid (Diptera) response in northern Australia

1. Chironomidae, sampled by interception of drifting cast pupal exuviae, responded to inputs of acid, heavy metal-rich waters in a seasonally flowing tropical stream in northern Australia.
2. Responses included gain of distinctive (indicative) taxa, loss of some species typical of pristine conditions, and increase in species richness.
3. Experimental manipulation (upstream diversion) of a mine adit entry showed that these responses were the result of change in water quality.
4. The higher species richness at low pH, which is contrary to temperate studies, may be explained by the large tropical (Australian and south-east Asian) pool of species tolerant of naturally occurring acidic aquatic habitats.
5. The structure and responses of the exuvial-assessed chironomid community matched long-term larval data.     

Response of stream macroinvertebrate assemblages to erosion control structures in a wastewater dominated urban stream in the southwestern U.S.

Effects of stream erosion control structures on aquatic macroinvertebrates were studied (2000–2009) in a wastewater dominated drainage (Wash) in Las Vegas, Nevada. Mainstem sites with and without structures, wastewater treatment plant outfalls, a reference site above treatment plant inputs, and tributary sites were sampled. Ordination suggested hydrology and channel characteristics (current velocity, stream depth, and width), and water quality (conductivity) were primary factors in organizing macroinvertebrate communities, with some variables altered at structures. Treatment plant inputs changed hydrology (increased flows), water chemistry (conductivity decreased below treatment plants), and temperature. Assemblages differed between site types, with midges and damselflies important at tributary sites and Fallceon mayflies and Smicridea caddisflies common at erosion control structures. Locally unique communities developed at structures which also may have facilitated exotic species invasions. Analyses showed that taxa richness increased over time at these sites and differed significantly from richness at sites without structures. Structures appeared important in retaining organic matter and, among mainstem sites, coarse particulate organic matter was highest, but variable, at structures and at wetlands above the structures. Erosion control structures, coupled with warm effluent, high baseflows, and altered water quality resulted in development of a macroinvertebrate community that did not trend towards reference or tributary sites. In this case, ecological communities at structures used for river restoration were not on a continuum between disturbed and reference sites. Goal setting of community responses at these structures would have required insight beyond the simple use of reference site attributes.     

微生物在水环境污染物降解中的应用

每年有大量来自工业、农业、养殖业和城市污水处理厂的废水被排入到水环境中, 因此, 地球上的水环境面临大量来自生活废水、工农业废水、非法排放的废水及其它废水的污染物质(如抗生素、杀虫剂、除草剂、烃等)的严重挑战, 特别是近年来随着集约化养殖的发展, 废水污染问题日益突出, 并且随着分析手段的进步, 能够检测到被排入水环境中的化学污染物质也越来越多, 这些化学污染物对水环境中的生物产生有害影响。但是, 微生物在污染控制上具有许多重要的作用。因此, 本文对微生物在水环境污染物降解中的应用进行了评论。结果表明微生物主要是应用在水产养殖水中, 而在其它的水体系(如河、湖、海)的应用较少。     

微生物在水环境污染物降解中的应用

每年有大量来自工业、农业、养殖业和城市污水处理厂的废水被排入到水环境中,因此,地球上的水环境面临大量来自生活废水、工农业废水、非法排放的废水及其它废水的污染物质(如抗生素、杀虫剂,除草剂、烃等)的严重挑战,特别是近年来随着集约化养殖的发展,废水污染问题日益突出,并且随着分析手段的进步,能够检测到被排入水环境中的化学污染物质也越来越多,这些化学污染物对水环境中的生物产生有害影响.但是,微生物在污染控制上具有许多重要的作用.因此,本文对微生物在水环境污染物降解中的应用进行了评论.结果表明微生物主要是应用在水产养殖水中,而在其它的水体系(如河、湖、海)的应用较少.     

微生物在水环境污染物降解中的应用（英文稿）

每年有大量来自工业、农业、养殖业和城市污水处理厂的废水被排入到水环境中, 因此, 地球上的水环境面临大量来自生活废水、工农业废水、非法排放的废水及其它废水的污染物质(如抗生素、杀虫剂、除草剂、烃等)的严重挑战, 特别是近年来随着集约化养殖的发展, 废水污染问题日益突出, 并且随着分析手段的进步, 能够检测到被排入水环境中的化学污染物质也越来越多, 这些化学污染物对水环境中的生物产生有害影响。但是, 微生物在污染控制上具有许多重要的作用。因此, 本文对微生物在水环境污染物降解中的应用进行了评论。结果表明微生物主要是应用在水产养殖水中, 而在其它的水体系(如河、湖、海)的应用较少。     

Development and Application of a Predictive Model of Freshwater Fish Assemblage Composition to Evaluate River Health in Eastern Australia

Multivariate predictive models are widely used tools for assessment of aquatic ecosystem health and models have been successfully developed for the prediction and assessment of aquatic macroinvertebrates, diatoms, local stream habitat features and fish. We evaluated the ability of a modelling method based on the River InVertebrate Prediction and Classification System (RIVPACS) to accurately predict freshwater fish assemblage composition and assess aquatic ecosystem health in rivers and streams of south-eastern Queensland, Australia. The predictive model was developed, validated and tested in a region of comparatively high environmental variability due to the unpredictable nature of rainfall and river discharge. The model was concluded to provide sufficiently accurate and precise predictions of species composition and was sensitive enough to distinguish test sites impacted by several common types of human disturbance (particularly impacts associated with catchment land use and associated local riparian, in-stream habitat and water quality degradation). The total number of fish species available for prediction was low in comparison to similar applications of multivariate predictive models based on other indicator groups, yet the accuracy and precision of our model was comparable to outcomes from such studies. In addition, our model developed for sites sampled on one occasion and in one season only (winter), was able to accurately predict fish assemblage composition at sites sampled during other seasons and years, provided that they were not subject to unusually extreme environmental conditions (e.g. extended periods of low flow that restricted fish movement or resulted in habitat desiccation and local fish extinctions).     

Short-term effect of oxic to anoxic transition on benthic microbial activity and solute fluxes in organic-rich phytotreatment ponds

Macroinvertebrates are one of the key components of lake ecosystems and are required to be monitored alongside other biological groups to define ecological status according to European Union legislation. Macroinvertebrate communities are highly variable and complex and respond to a diverse series of environmental conditions. The purpose of this study was to examine the relative importance of environmental variables in explaining macroinvertebrate abundance. A total of 45 sub-alpine lakes were sampled for macroinvertebrates in the shallow sublittoral. Environmental variables were grouped into four types: (1) aquatic physical and chemical parameters, (2) littoral and riparian habitat, (3) lake morphometric parameters and (4) sediment chemical characteristics. Nonparametric multiplicative regression (NPMR) was used to model the abundance of individual macroinvertebrate taxa. Significant models were produced for nine out of the 24 taxa examined. Sediment characteristics were the group most frequently included in models and also the factors to which taxa abundance was the most sensitive. Aquatic physical and chemical variables were the next group most frequently included in models although chlorophyll a was not included in any of the models and total phosphorus in only one. This indicates that many taxa may not show a direct easily interpretable response to eutrophication pressure. Lake morphometric factors were included in several of the models although the sensitivity of macroinvertebrate abundance tended to be lower than for sediment and aquatic physical and chemical factors. Habitat factors were only included in three models although riparian vegetation was found to have a significant influence on the abundance of Ephemera danica indicating that ecotone integrity is likely to play a role in its ecology. Overall, the models tended to be specific for species with limited commonality across taxa. Models produced by NPMR indicate that the response of macroinvertebrates to environmental variables can be successfully described but further research is required focussing in more detail on the response of key taxa to relevant environmental parameters and anthropogenic pressures.     

Large-scale multi-trophic co-response models and environmental control of pelagic food webs in Québec lakes

Environmental heterogeneity plays a fundamental role in driving species distributions by, for one, fostering niche dimensionality. Within lake ecosystems, species distributions and concordance patterns are driven by both local and regional heterogeneity, though their relative importance across trophic levels has rarely been explored. We developed a statistical framework to compare responses of taxa from different trophic levels to abiotic factors and determine how this affected multi-trophic network structures. In particular, we used multi-species concordance modelling (concordance analysis and RV coefficient) to determine species associations and correlations within and among three trophic levels (phytoplankton, zooplankton and fish communities sampled across 49 southern Québec lakes, covering eight hydrological regions). We then used multiple factor analysis, latent variable modelling and local contributions of sites to beta diversity to assess the relative importance of major environmental gradients in structuring species co-responses and species interaction turnover across the landscape. Our analyses confirmed that concordant species within each trophic level varied jointly or segregated into different pelagic food webs in Québec lakes where important acidification and eutrophication took place. Some keynote species were indicators of different food web compartments and distinguished groups of lakes along multiple environmental niche dimensions. Among the three trophic levels examined, zooplankton depicted the highest proportion of species concordance and appeared to act as a trophic linkage between phytoplankton and fish. Ultimately, the losses or gains in species richness and species interactions were strongly driven by environmental gradients. This study provides for the first time a combined analysis of the effects of environmental heterogeneity on ecological communities belonging to three trophic levels sampled near simultaneously across an 800 km broad lacustrine landscape. The new framework developed in this study has a great potential to better understand the complex response of aquatic ecosystems in a world increasingly affected by multiple, cumulative stressors.     

Comparative biodiversity of crustaceans and aquatic insects from various water body types in coastal Mediterranean wetlands

Coastal wetlands are characterized by a high biodiversity. At the same time, biodiversity is one of the main criteria used to establish protection policy priorities, or to propose management actions. In this study, crustacean and aquatic insect species richness in the Empordà wetlands was investigated. These two groups contribute in an important way to the total biodiversity, and still they are seldom taken into account in the management of natural areas. Representative samples (38 points) of all aquatic water body types in the Empordà wetlands were taken monthly (dip net with 250 μm mesh). Sampling was carried out between 1996 and 2000, but until present, only qualitative data have been extracted. A rich fauna of 125 crustacean taxa and 295 aquatic insect taxa were found. Some environments were characterized by low richness and high singularity (isolated artesian freshwater springs), some by high richness and high singularity (estuarine waters, brackish and meso-eutrophic freshwater wetlands), and others by low richness and low singularity (hypertrophic freshwater wetlands and hyperhaline wetlands). Factors determining singularity and richness are discussed. Comparison with crustacean richness of other western Mediterranean wetlands showed a similar high species richness in our study sites, probably due to high spatial heterogeneity of these areas.     

Ordination of deep river invertebrate communities in relation to environmental variables

A deep Main river was examined to determine the effects of selected environmental variables on benthic invertebrate community structure. Thirty-three sites were sampled by divers using artificial substrates. The Bray-Curtis ordination was used to establish community types based upon combinations of current velocity, siltation, and organic detritus. While some invertebrates were tightly clustered within particular communities, most taxa tended to concentrate in one community type but were not excluded from others. The results tended to support the individualistic hypothesis of species distribution.     

贵州省环境中汞污染现状与分布特征

贵州是我国汞矿的主要产地,其储量和产量均居全国首位,因此造成了该区域环境受到广泛的汞污染。从大的区域尺度上研究汞的污染分布特征对于了解该区域汞的污染现状有很好的指导作用。通过对贵州省汞污染源及各环境介质中汞污染情况的调查,首先阐释了万山、务川、滥木厂等几个主要汞矿区及燃煤和有机化工等行业的汞污染现状;并从大气、土壤和水体等环境介质方面综合分析了贵州地区汞的暴露水平与分布特征;采用ArcGIS 10.0描绘了各环境介质中总汞及甲基汞的分布特征。结果表明贵州省东北部与西南部汞矿区汞污染程度较高,大气、土壤和水体中的总汞分布呈明显的区域性,汞矿毗邻区域明显高于其他区域,矿区和城镇水体中甲基汞浓度较高,表明汞矿区和人为活动等因素影响水体中的甲基汞的分布。     

Effects of organic and heavy metal pollution on chironomids within a pristine upland catchment

Several studies, particularly in the Northern Hemisphere, have demonstrated that chironomids are responsive to pollution (e.g., heavy metals, organic). In Australia, there is limited evidence that chironomid species have differential sensitivities to water pollution, with several studies reporting high tolerance of heavy metal pollution. We investigated the impact of both zinc-rich mine waste and organic effluent on chironomids within an effectively pristine background using the Chironomid Pupal Exuviae Technique (CPET). Chironomid species assemblages were strongly influenced by both mine drainage and organic pollution. Community composition differed between unpolluted streams and locations downstream of the pollution sources, and between the two different sources of pollution. Thirty seven of the most abundant species exhibited strong responses to water pollution varying from greatly increased abundance to complete absence. Ten species had higher abundance at one of the polluted sites compared to unpolluted sites; six in the presence of zinc pollution and five in the presence of organic pollution. One species responded positively to both pollution types. Our results indicate that contrary to the mixed reports of Australian chironomids for being insensitive to pollution, we found that they displayed a strong pollution response to both organic and heavy metal contamination.     

Colonization,variability, and the use of substratum-filled trays for biomonitoring benthic communities

Sampling variability and colonization rate of introduced substrates (plastic trays filled with pebble and cobble) in two southwestern Virginia streams are described. Substrates were rapidly colonized by aquatic macroinvertebrates, but colonization rates differed between years, possibly due to annual variability in macroinvertebrate abundance. To examine the applicability of using these substrates for biomonitoring benthic communities, trays were placed at several locations in a river receiving power plant discharges. Only six samples were necessary to detect a 15%reduction in macroinvertebrate density and a 12% reduction in number of taxa at effluent sites. Benthic communities established on rock-filled trays and multiplate samplers collected from the same stations during the same period were compared. Although multiplate samplers were more variable than rock trays and were selective for different taxa, both substrate types showed significant differences in community parameters among locations. Rock trays at all sites were dominated by Cheumatopsyche sp., whereas chironomids were more abundant on multiplate samplers. The relative abundance of mayflies was reduced at the effluent site on both substrate types.