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Sample records for macroinvertebrate assemblage measures

  1. Benthic macroinvertebrate assemblages in mangroves and open ...

    African Journals Online (AJOL)

    Benthic macroinvertebrate assemblages in mangroves and open intertidal areas on the Dar es Salaam coast, Tanzania. ... it is recommended that conservation efforts along the Tanzanian coast should focus here. Keywords: benthic macrofauna, community structure, littoral zone, Tanganyika, Western Indian Ocean ...

  2. The Colonization of Newly Built Fishponds by the Macroinvertebrate Assemblages

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    Pavla Řezníčková

    2016-01-01

    Full Text Available The succession of standing waters by aquatic macroinvertebrates is a present and insufficiently surveyed topic. This study is addressed to the issue of colonisation of newly created small standing waters. Two fishponds situated in the north of Moravia (Czech Republic were studied. The aim of this study was to determine the character and colonisation rate of these ponds by macroinvertebrates, to evaluate the abundance, taxonomic composition and changes in composition of freshwater assemblages as a result of the fish stock influence. Basic abiotic parameters were also measured within the sampling occasions (e.g. water temperature, dissolved oxygen, conductivity, pH, total nitrogen and phosphorus concentrations. Samples of aquatic macroinvertebrates were taken monthly during the years 2012 and 2013, by kick sampling method using the hand net. The character of sampled fishponds was very similar, environmental parameters (e.g. area, substrate, depth etc. were comparable. The colonisation of both fishponds was very fast. The pioneer colonists were mainly insect larvae (e.g. chironomids. Very low numbers of macroinvertebrates as a result of fish stock influence were recorded on both sites during the observation with the highest abundances in summer season.

  3. Effects of oil pollution on aquatic macroinvertebrate assemblages in ...

    African Journals Online (AJOL)

    Macroinvertebrate assemblages from uncontaminated and contaminated sites in the Gamba Complex (Gabon) were compared, the latter sites having been subjected to ongoing oil spills since the 1970s. Vegetation communities surrounding the sites included savannah, shrub–scrub, palm forest, gallery forest and thick ...

  4. Fish stomach contents in benthic macroinvertebrate assemblage assessments

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    TH. Tupinambás

    Full Text Available The choice of sampling gears to assess benthic macroinvertebrate communities depends on environmental characteristics, study objectives, and cost effectiveness. Because of the high foraging capacity and diverse habitats and behaviors of benthophagous fishes, their stomach contents may offer a useful sampling tool in studies of benthic macroinvertebrates, especially in large, deep, fast rivers that are difficult to sample with traditional sediment sampling gear. Our objective was to compare the benthic macroinvertebrate communities sampled from sediments with those sampled from fish stomachs. We collected benthic macroinvertebrates and fish from three different habitat types (backwater, beach, riffle in the wet season, drying season, and dry season along a single reach of the Grande River (Paraná River Basin, southeast Brazil. We sampled sediments through use of a Petersen dredge (total of 216 grabs and used gill nets to sample fish (total of 36 samples. We analyzed the stomach contents of three commonly occurring benthophagous fish species (Eigenmannia virescens, Iheringichthys labrosus, Leporinus amblyrhynchus. Chironomids dominated in both sampling methods. Macroinvertebrate taxonomic composition and abundances from fish stomachs differed from those from sediment samples, but less so from riffles than from backwater and beach habitats. Macroinvertebrate taxa from E. virescens stomachs were more strongly correlated with sediment samples from all three habitats than were those from the other two species. The species accumulation curves and higher mean dispersion values, compared with with sediment samples suggest that E. virescens is more efficient than sediment samples and the other fish studied at collecting benthic taxa. We conclude that by analyzing the stomach contents of benthophagous fishes it is possible to assess important characteristics of benthic communities (dispersion, taxonomic composition and diversity. This is especially true

  5. Downstream effects of hydropower production on aquatic macroinvertebrate assemblages in two rivers in Costa Rica.

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    Chaves-Ulloa, Ramsa; Umaña-Villalobos, Gerardo; Springer, Monika

    2014-04-01

    Despite the fact that little is known about the consequences of hydropower production in tropical areas, many large dams (> 15 m high) are currently under construction or consideration in the tropics. We researched the effects of large hydroelectric dams on aquatic macroinvertebrate assemblages in two Costa Rican rivers. We measured physicochemical characteristics and sampled aquatic macroinvertebrates from March 2003 to March 2004 in two dammed rivers, Peñas Blancas and San Lorenzo, as well as in the undammed Chachagua River. Sites above and below the dam had differences in their physicochemical variables, with wide variation and extreme values in variables measured below the dam in the San Lorenzo River. Sites below the dams had reduced water discharges, velocities, and depths when compared with sites above the dams, as well as higher temperatures and conductivity. Sites above dams were dominated by collector-gatherer-scrapers and habitat groups dominated by swimmer-clingers, while sites below dams had a more even representation of groups. In contrast, a comparison between two sites at different elevation in the undammed river maintained a similar assemblage composition. Tributaries might facilitate macroinvertebrate recovery above the turbine house, but the assemblage below the turbine house resembled the one below the dam. A massive sediment release event from the dam decreased the abundance per sample and macroinvertebrate taxa below the dam in the Peñas Blancas River. Our study illustrates the effects of hydropower production on neotropical rivers, highlighting the importance of using multiple measures of macroinvertebrate assemblage structure for assessing this type of environmental impact.

  6. Benthic Macroinvertebrate Assemblages in the Near Coastal Zone of Lake Erie

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    Benthic macroinvertebrate assemblages have been used as indicators of ecological condition because their responses integrate localized environmental conditions of the sediments and overlying water. Assemblages of benthic invertebrates in the near coastal region are of particular...

  7. Effects of Management Legacies on Stream Fish and Aquatic Benthic Macroinvertebrate Assemblages

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    Quist, Michael C.; Schultz, Randall D.

    2014-09-01

    Fish and benthic macroinvertebrate assemblages often provide insight on ecological conditions for guiding management actions. Unfortunately, land use and management legacies can constrain the structure of biotic communities such that they fail to reflect habitat quality. The purpose of this study was to describe patterns in fish and benthic macroinvertebrate assemblage structure, and evaluate relationships between biota and habitat characteristics in the Chariton River system of south-central Iowa, a system likely influenced by various potential management legacies (e.g., dams, chemical removal of fishes). We sampled fishes, benthic macroinvertebrates, and physical habitat from a total of 38 stream reaches in the Chariton River watershed during 2002-2005. Fish and benthic macroinvertebrate assemblages were dominated by generalist species tolerant of poor habitat quality; assemblages failed to show any apparent patterns with regard to stream size or longitudinal location within the watershed. Metrics used to summarize fish assemblages and populations [e.g., presence-absence, relative abundance, Index of Biotic Integrity for fish (IBIF)] were not related to habitat characteristics, except that catch rates of piscivores were positively related to the depth and the amount of large wood. In contrast, family richness of benthic macroinvertebrates, richness of Ephemeroptera, Trichoptera, and Plecoptera taxa, and IBI values for benthic macroinvertebrates (IBIBM) were positively correlated with the amount of overhanging vegetation and inversely related to the percentage of fine substrate. A long history of habitat alteration by row-crop agriculture and management legacies associated with reservoir construction has likely resulted in a fish assemblage dominated by tolerant species. Intolerant and sensitive fish species have not recolonized streams due to downstream movement barriers (i.e., dams). In contrast, aquatic insect assemblages reflected aquatic habitat, particularly

  8. Seasonal comparison of aquatic macroinvertebrate assemblages in a flooded coastal freshwater marsh

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    Kang, Sung-Ryong; King, Sammy L.

    2013-01-01

    Marsh flooding and drying may be important factors affecting aquatic macroinvertebrate density and distribution in coastal freshwater marshes. Limited availability of water as a result of drying in emergent marsh may decrease density, taxonomic diversity, and taxa richness. The principal objectives of this study are to characterize the seasonal aquatic macroinvertebrate assemblage in a freshwater emergent marsh and compare aquatic macroinvertebrate species composition, density, and taxonomic diversity to that of freshwater marsh ponds. We hypothesize that 1) freshwater emergent marsh has lower seasonal density and taxonomic diversity compared to that of freshwater marsh ponds; and 2) freshwater emergent marsh has lower taxa richness than freshwater marsh ponds. Seasonal aquatic macroinvertebrate density in freshwater emergent marsh ranged from 0 organisms/m2 (summer 2009) to 91.1 ± 20.53 organisms/m2 (mean ± SE; spring 2009). Density in spring was higher than in all other seasons. Taxonomic diversity did not differ and there were no unique species in the freshwater emergent marsh. Our data only partially support our first hypothesis as aquatic macroinvertebrate density and taxonomic diversity between freshwater emergent marsh and ponds did not differ in spring, fall, and winter but ponds supported higher macroinvertebrate densities than freshwater emergent marsh during summer. However, our data did not support our second hypothesis as taxa richness between freshwater emergent marsh and ponds did not statistically differ.

  9. Effects of anthropogenic impacts on benthic macroinvertebrates assemblages in subtropical mountain streams

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    Leticia M. Mesa

    2013-12-01

    Full Text Available The nature of the riparian and surrounding landscape has been modified by anthropogenic activities, which may subsequently alter the composition and functional structure of macroinvertebrate assemblages. The effect of these changes on function of benthic fauna is difficult to assess due to the scarce knowledge on functional structures in tropical streams. In this study we evaluate whether sites impacted and unimpacted by anthropogenic alterations differed in assemblage composition and density, richness and diversity of each functional feeding group. The selection of the sites was related to their distinct riparian characteristics, following the QBRy riparian quality index. Collector-gatherer was the dominant functional feeding group, comprising 91% of total density, whereas the proportion of shredders was very low, representing less of 0.5% of total density. Asemblage composition of macroinvertebrates differed between impacted and unimpacted sites. Predators were dominant in taxa number, representing about 60% of total taxa richness. In addition, the diversity and richness of collector-gatherers differed significantly between degraded and unimpacted sites, reflecting the sensitivity of this group to environmental changes and the utility to be used in the assessment of anthropogenic modifications. The results of this study reinforce the idea that riparian corridor management is critical for the distribution of macroinvertebrate assemblages as well as functional organization of lotic streams.

  10. Macroinvertebrate assemblages in agricultural, mining, and urban tropical streams: implications for conservation and management.

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    Mwedzi, Tongayi; Bere, Taurai; Mangadze, Tinotenda

    2016-06-01

    The study evaluated the response of macroinvertebrate assemblages to changes in water quality in different land-use settings in Manyame catchment, Zimbabwe. Four land-use categories were identified: forested commercial farming, communal farming, Great Dyke mining (GDM) and urban areas. Macroinvertebrate community structure and physicochemical variables data were collected in two seasons from 41 sites following standard methods. Although not environmentally threatening, urban and GDM areas were characterised by higher conductivity, total dissolved solids, salinity, magnesium and hardness. Chlorides, total phosphates, total nitrogen, calcium, potassium and sodium were significantly highest in urban sites whilst dissolved oxygen (DO) was significantly higher in the forested commercial faming and GDM sites. Macroinvertebrate communities followed the observed changes in water quality. Macroinvertebrates in urban sites indicated severe pollution (e.g. Chironomidae) whilst those in forested commercial farming sites and GDM sites indicated relatively clean water (e.g. Notonemouridae). Forested watersheds together with good farm management practices are important in mitigating impacts of urbanisation and agriculture. Strategies that reduce oxygen-depleting substances must be devised to protect the health of Zimbabwean streams. The study affirms the wider applicability of the South African Scoring System in different land uses.

  11. Assessing disruption of longitudinal connectivity on macroinvertebrate assemblages in a semiarid lowland river

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    Marta Leiva

    2017-12-01

    Full Text Available Abstract Aim: Our aim in this study was evaluate the effects of flow regulation for irrigation on the macroinvertebrate assemblages in a semiarid river. Methods We sampled two reaches in Dulce River; one placed upstream a weir that diverts flow into a network of irrigation channels and the other downstream that weir, in the assessment of the fluvial discontinuity. We assess the differences among reaches and sites, environmental variables, invertebrate density, richness and Shannon-Wiener index applying non-parametric analyses of variance Kruskal Wallis. The similarity percentage analysis (SIMPER was used to identify which species contributed to the dissimilarities on macroinvertebrate assemblage structure. Canonical Correspondence Analysis (CCA was performed with the total set of samples to explore macroinvertebrate distribution in reaches and associations of the assemblages with habitat variables. Results The density, richness and Shannon index values did not show differences between the reaches located upstream and downstream. Beta diversity (Whittaker was 0.72 among upstream sites, 0.56 among downstream sites and higher species turnover (0.73 was obtained between both reaches. The Canonical Correspondence Analysis explained 46.71% of the variance differentiating upstream sites explained by higher values of organic matter of bottom sediments and discharge, high density of Nais communis, Bothrioneurum americanum, Pelomus, Stephensoniana trivandrana, Pristina menoni, P. jenkinae, P.longidentata, P. americana, Dero obtusa, Endotribelos, Heleobia and Turbellaria. The downstream sites were associated to coarser substratum and higher density of Lopescladius, Polypedilum, Cricotopus, Thienamaniella, Cryptochironomus, Baetidae, Nematoda and Corbicula fluminea. Conclusions The low-flow disturbance had effects on the composition of the benthic invertebrate assemblages, but attributes (such as density and richness showed a lower variability probably

  12. The impact of sediment removal on the aquatic macroinvertebrate assemblage in a fishpond littoral zone

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    Zdeněk ADÁMEK

    2011-02-01

    Full Text Available Bottom sediment removal, a widely used technique in restoration management of standing water bodies, has a strong influence on communities of aquatic organisms. As most information on the impact of sediment removal on the aquatic environment comes from studies on lakes, the aim of this study was to describe macroinvertebrate assemblage succession in a fishpond (Štěpánek fishpond, Bohemian-Moravian highlands, Czech Republic littoral zone following restoration by sediment removal during the winter of 2003/2004. Semi-quantitative hand net sampling was undertaken one year before (2003 and in each of the following five years (2004–2008 after sediment removal. A significant decrease in both abundance (approx. 90% of individuals and diversity (approx. 30% of taxa of macroinvertebrates was detected immediately after pond restoration. The values gradually increased over subsequent years, reaching comparable abundance and diversity three years after sediment removal. A significant shift was recorded in the taxonomic and functional composition of the macroinvertebrate assemblage after sediment removal. Mayfly larvae were the dominant invertebrates before restoration, while chironomid larvae and oligochaetes dominated after sediment removal. Phytophilous taxa, grazers and scrapers, and swimming or diving invertebrates were common in 2003, whilst open-water taxa preferring mud and other mostly inorganic microhabitats, gatherers/collectors, and burrowing/boring invertebrates were relatively common after sediment removal. In 2008, the assemblage reverted towards the situation before sediment removal, probably connected with a lower water level and accelerated macrophyte bed succession. Principal Component Analysis on the species data confirmed the differences in invertebrate taxonomic structure among sampling years. Succession of the fishpond invertebrate assemblage in the years following sediment removal was mainly influenced by fish farming practice and

  13. The value of enduring environmental surrogates as predictors of estuarine benthic macroinvertebrate assemblages

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    Wildsmith, Michelle D.; Valesini, Fiona J.; Robinson, Samuel F.

    2017-10-01

    This study tested the extent to which spatial differences in the benthic macroinvertebrate assemblages of a temperate microtidal estuary were 'explained' by the enduring (biophysical) vs non-enduring (water and sediment quality) environmental attributes of a diverse range of habitats, and thus the potential of those environmental surrogates to support faunal prediction. Species composition differed significantly among habitats in each season, with the greatest differences occurring in winter and spring and the least in summer. The pattern of habitat differences, as defined by their enduring environmental characteristics, was significantly and well matched with that in the fauna in each season. In contrast, significant matches between the non-enduring environmental and faunal data were only detected in winter and/or spring, and to a lesser extent. Field validation of the faunal prediction capacity of the biophysical surrogate framework at various 'test' sites throughout the estuary showed good agreement between the actual vs predicted key species. These findings demonstrate that enduring environmental criteria, which can be readily measured from mapped data, provide a better and more cost-effective surrogate for explaining spatial differences in the invertebrate fauna of this system than non-enduring criteria, and are thus a promising basis for faunal prediction. The approaches developed in this study are also readily adapted to any estuary worldwide.

  14. Non-indigenous macroinvertebrate species in Lithuanian fresh waters, Part 2: Macroinvertebrate assemblage deviation from naturalness in lotic systems and the consequent potential impacts on ecological quality assessment

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    Arbačiauskas K.

    2011-12-01

    Full Text Available The biological pressure represented by non-indigenous macroinvertebrate species (NIMS should be addressed in the implementation of EU Water Framework Directive as this can have a direct impact on the ’naturalness’ of the invaded macroinvertebrate assemblage. The biocontamination concept allows assessment of this deviation from naturalness, by evaluation of abundance and disparity contamination of an assemblage. This study aimed to assess the biocontamination of macroinvertebrate assemblages in Lithuanian rivers, thereby revealing the most high-impact non-indigenous species, and to explore the relationship between biocontamination and conventional metrics of ecological quality. Most of the studied rivers appeared to be impacted by NIMS. The amphipods Pontogammarus robustoides, Chelicorophium curvispinum and snail Litoglyphus naticoides were revealed as high-impact NIMS for Lithuanian lotic systems. Metrics of ecological quality which largely depend upon the richness of indicator taxa, such as the biological monitoring working party (BMWP score and Ephemeroptera/Plecoptera/Trichoptera (EPT taxa number, were negatively correlated with biocontamination, implying they could provide unreliable ecological quality estimates when NIMS are present. Routine macroinvertebrate water quality monitoring data are sufficient for generation of the biocontamination assessment and thus can provide supplementary information, with minimal extra expense or effort. We therefore recommend that biocontamination assessment is included alongside established methods for gauging biological and chemical water quality.

  15. Relationships of sedimentation and benthic macroinvertebrate assemblages in headwater streams using systematic longitudinal sampling at the reach scale.

    Science.gov (United States)

    Longing, S D; Voshell, J R; Dolloff, C A; Roghair, C N

    2010-02-01

    Investigating relationships of benthic invertebrates and sedimentation is challenging because fine sediments act as both natural habitat and potential pollutant at excessive levels. Determining benthic invertebrate sensitivity to sedimentation in forested headwater streams comprised of extreme spatial heterogeneity is even more challenging, especially when associated with a background of historical and intense watershed disturbances that contributed unknown amounts of fine sediments to stream channels. This scenario exists in the Chattahoochee National Forest where such historical timber harvests and contemporary land-uses associated with recreation have potentially affected the biological integrity of headwater streams. In this study, we investigated relationships of sedimentation and the macroinvertebrate assemblages among 14 headwater streams in the forest by assigning 30, 100-m reaches to low, medium, or high sedimentation categories. Only one of 17 assemblage metrics (percent clingers) varied significantly across these categories. This finding has important implications for biological assessments by showing streams impaired physically by sedimentation may not be impaired biologically, at least using traditional approaches. A subsequent multivariate cluster analysis and indicator species analysis were used to further investigate biological patterns independent of sedimentation categories. Evaluating the distribution of sedimentation categories among biological reach clusters showed both within-stream variability in reach-scale sedimentation and sedimentation categories generally variable within clusters, reflecting the overall physical heterogeneity of these headwater environments. Furthermore, relationships of individual sedimentation variables and metrics across the biological cluster groups were weak, suggesting these measures of sedimentation are poor predictors of macroinvertebrate assemblage structure when using a systematic longitudinal sampling design

  16. Effects of local land-use on riparian vegetation, water quality, and the functional organization of macroinvertebrate assemblages.

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    Fierro, Pablo; Bertrán, Carlos; Tapia, Jaime; Hauenstein, Enrique; Peña-Cortés, Fernando; Vergara, Carolina; Cerna, Cindy; Vargas-Chacoff, Luis

    2017-12-31

    Land-use change is a principal factor affecting riparian vegetation and river biodiversity. In Chile, land-use change has drastically intensified over the last decade, with native forests converted to exotic forest plantations and agricultural land. However, the effects thereof on aquatic ecosystems are not well understood. Closing this knowledge gap first requires understanding how human perturbations affect riparian and stream biota. Identified biological indicators could then be applied to determine the health of fluvial ecosystems. Therefore, this study investigated the effects of land-use change on the health of riparian and aquatic ecosystems by assessing riparian vegetation, water quality, benthic macroinvertebrate assemblages, and functional feeding groups. Twenty-one sites in catchment areas with different land-uses (i.e. pristine forests, native forests, exotic forest plantations, and agricultural land) were selected and sampled during the 2010 to 2012 dry seasons. Riparian vegetation quality was highest in pristine forests. Per the modified Macroinvertebrate Family Biotic Index for Chilean species, the best conditions existed in native forests and the worst in agricultural catchments. Water quality and macroinvertebrate assemblages significantly varied across land-use areas, with forest plantations and agricultural land having high nutrient concentrations, conductivity, suspended solids, and apparent color. Macroinvertebrate assemblage diversity was lowest for agricultural and exotic forest plantation catchments, with notable non-insect representation. Collector-gatherers were the most abundant functional feeding group, suggesting importance independent of land-use. Land-use areas showed no significant differences in functional feeding groups. In conclusion, anthropogenic land-use changes were detectable through riparian quality, water quality, and macroinvertebrate assemblages, but not through functional feeding groups. These data, particularly the

  17. Effects of sea lamprey substrate modification and carcass nutrients on macroinvertebrate assemblages in a small Atlantic coastal stream

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    Weaver, Daniel M.; Coghlan, Stephen M.; Zydlewski, Joseph D.

    2018-01-01

    Aquatic macroinvertebrates respond to patch dynamics arising from interactions of physical and chemical disturbances across space and time. Anadromous fish, such as sea lamprey, Petromyzon marinus, migrate from the ocean and alter physical and chemical properties of recipient spawning streams. Sea lamprey disturb stream benthos physically through nest construction and spawning, and enrich food webs through nutrient deposition from decomposing carcasses. Sea lamprey spawning nests support greater macroinvertebrate abundance than adjacent reference areas, but concurrent effects of stream bed modification and nutrient supplementation have not been examined sequentially. We added carcasses and cleared substrate experimentally to mimic the physical disturbance and nutrient enrichment associated with lamprey spawning, and characterized effects on macroinvertebrate assemblage structure. We found that areas receiving cleared substrate and carcass nutrients were colonized largely by Simuliidae compared to upstream and downstream control areas that were colonized largely by Hydropsychidae, Philopotamidae, and Chironomidae. Environmental factors such as stream flow likely shape assemblages by physically constraining macroinvertebrate establishment and feeding. Our results indicate potential changes in macroinvertebrate assemblages from the physical and chemical changes to streams brought by spawning populations of sea lamprey.

  18. Environmental stressors as a driver of the trait composition of benthic macroinvertebrate assemblages in polluted Iberian rivers.

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    Kuzmanovic, Maja; Dolédec, Sylvain; de Castro-Catala, Nuria; Ginebreda, Antoni; Sabater, Sergi; Muñoz, Isabel; Barceló, Damià

    2017-07-01

    We used the trait composition of macroinvertebrate communities to identify the effects of pesticides and multiple stressors associated with urban land use at different sites of four rivers in Spain. Several physical and chemical stressors (high metal pollution, nutrients, elevated temperature and flow alterations) affected the urban sites. The occurrence of multiple stressors influenced aquatic assemblages at 50% of the sites. We hypothesized that the trait composition of macroinvertebrate assemblages would reflect the strategies that the assemblages used to cope with the respective environmental stressors. We used RLQ and fourth corner analysis to address the relationship between stressors and the trait composition of benthic macroinvertebrates. We found a statistically significant relationship between the trait composition and the exposure of assemblages to environmental stressors. The first RLQ dimension, which explained most of the variability, clearly separated sites according to the stressors. Urban-related stressors selected taxa that were mainly plurivoltine and fed on deposits. In contrast, pesticide impacted sites selected taxa with high levels of egg protection (better egg survival), indicating a potentially higher risk for egg mortality. Moreover, the trait diversity of assemblages at urban sites was low compared to that observed in pesticide impacted sites, suggesting the homogenization of assemblages in urban areas. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  19. Effects of extreme floods on macroinvertebrate assemblages in tributaries to the Mohawk River, New York, USA

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    Calderon, Mirian R.; Baldigo, Barry P.; Smith, Alexander J.; Endreny, Theodore A.

    2017-01-01

    Climate change is forecast to bring more frequent and intense precipitation to New York which has motivated research into the effects of floods on stream ecosystems. Macroinvertebrate assemblages were sampled at 13 sites in the Mohawk River basin during August 2011, and again in October 2011, following historic floods caused by remnants of Hurricane Irene and Tropical Storm Lee. The annual exceedance probabilities of floods at regional flow-monitoring sites ranged from 0.5 to 0.001. Data from the first 2 surveys, and from additional surveys done during July and October 2014, were assessed to characterize the severity of flood impacts, effect of seasonality, and recovery. Indices of total taxa richness; Ephemeroptera, Plecoptera, and Trichoptera (EPT) richness; Hilsenhoff's biotic index; per cent model affinity; and nutrient biotic index-phosphorus were combined to calculate New York State Biological Assessment Profile scores. Analysis of variance tests were used to determine if the Biological Assessment Profile, its component metrics, relative abundance, and diversity differed significantly (p ≤ .05) among the four surveys. Only total taxa richness and Shannon–Wiener diversity increased significantly, and abundance decreased significantly, following the floods. No metrics differed significantly between the July and August 2014 surveys which indicates that the differences denoted between the August and October 2011 surveys were caused by the floods. Changes in taxa richness, EPT richness, and diversity were significantly correlated with flood annual exceedance probabilities. This study increased our understanding of the resistance and resilience of benthic macroinvertebrate communities by showing that their assemblages were relatively impervious to extreme floods across the region.

  20. Influence of agricultural land-use and pesticides on benthic macroinvertebrate assemblages in an agricultural river basin in southeast Brazil

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    M Egler

    Full Text Available Land-use alterations and pesticide run-offs are among the main causes for impairment in agricultural areas. We evaluated the influence of different land-uses (forest, pasture and intensive agriculture on the water quality and on benthic macroinvertebrate assemblages on three occasions: in the dry season, wet season and at the end of the wet season. Macroinvertebrates responded to this gradient of impairment: agricultural sites had significantly lower richness numbers than forested and pasture sites, and all major invertebrate groups were significantly affected. Most taxa found in forested sites were found in pasture sites, but often with lower densities. In this case, the loss of habitats due to sedimentation and the lower complexity of substrates seem to be the disruptive force for the macroinvertebrate fauna.

  1. Macroinvertebrate assemblages and biodiversity levels: ecological role of constructed wetlands and artificial ponds in a natural park

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    Laura Sartori

    2014-02-01

    Full Text Available Normal 0 14 false false false MicrosoftInternetExplorer4 Constructed wetlands play an important role in water supply, floodwater retention and nutrient removal, at the same time allowing the restoration of lost habitat and the preservation of biodiversity. There is little knowledge about the biodiversity that can be found in these artificial environments along time, especially at the invertebrate community level. Macroinvertebrate assemblages, water chemistry, morphology, and environmental characteristics of natural ponds, artificial pools and constructed wetlands in Parco Pineta (Northern Italy were studied to evaluate the effects of local factors on macroinvertebrate communities. The objective was to verify if each ecosystem could equally contribute to local biodiversity, regardless of its natural or artificial origin. Principal Components Analysis showed that ponds were divided into clusters, based on their morphology and their water quality, independently from their origin. The composition of macroinvertebrate communities was similar among natural wetlands and ponds artificially created to provide new habitats in the park, while it was different among natural wetlands and constructed wetlands created for wastewater treatment purposes. Biodiversity of natural ponds and constructed wetlands, evaluated using taxa richness, Shannon index, and Pielou index, was comparable. Canonical Correspondence Analysis highlighted differences in macroinvertebrate community composition and pointed out the relationships among macroinvertebrates and various environmental variables: habitat heterogeneity resulted as the most relevant factor that influences taxa richness. Water quality also affects the macroinvertebrate community structure. We determined that constructed wetlands with higher pollutant concentrations show different assemblage compositions but comparable overall macroinvertebrate biodiversity. Constructed wetlands became valuable ecological elements

  2. Nestedness and successional trajectories of macroinvertebrate assemblages in man-made wetlands.

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    Ruhí, Albert; Boix, Dani; Gascón, Stéphanie; Sala, Jordi; Quintana, Xavier D

    2013-02-01

    Current successional models, primarily those based on floral succession, propose several distinct trajectories based on the integration of two key hypotheses from succession theory: convergence versus divergence in species composition among successional sites, and progression towards versus deviation from a desired reference state. We applied this framework to faunal succession, including differential colonization between active and passive dispersers, and the nested patterns generated as a consequence of this peculiarity. Nine man-made wetlands located in three different areas, from 0-3 years from wetland creation, were assessed. In addition, 91 wetlands distributed throughout the region were used as references for natural macroinvertebrate communities. We predicted the following: (1) highly nested structures in pioneering assemblages will decrease to lower mid-term values due to a shift from active pioneering taxa to passive disperser ones; (2) passive idiosyncratic taxa will elicit divergent successional trajectories among areas; (3) the divergent trajectories will provoke lower local and higher regional diversity values in the mid-term assemblages than in pioneer assemblages. Our results were largely congruent with hypotheses (1) and (2), diverging from the anticipated patterns only in the case of the temporary wetlands area. However, overall diversity trends based on hypothesis (3) did not follow the expected pattern. The divergent successional trajectories did not compensate for regional biodiversity losses that occurred as a consequence of pioneering colonizer decline over time. Consequently, we suggest reconsidering wetland construction for mitigation purposes within mid-term time frames (≤ 3 years). Wetlands may not offset, within this temporal scenario, regional biodiversity loss because the ecosystem may not support idiosyncratic taxa from natural wetlands.

  3. Compliance of secondary production and eco-exergy as indicators of benthic macroinvertebrates assemblages' response to canopy cover conditions in Neotropical headwater streams.

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    Linares, Marden Seabra; Callisto, Marcos; Marques, João Carlos

    2018-02-01

    Riparian vegetation cover influences benthic assemblages structure and functioning in headwater streams, as it regulates light availability and autochthonous primary production in these ecosystems.Secondary production, diversity, and exergy-based indicators were applied in capturing how riparian cover influences the structure and functioning of benthic macroinvertebrate assemblages in tropical headwater streams. Four hypotheses were tested: (1) open canopy will determine the occurrence of higher diversity in benthic macroinvertebrate assemblages; (2) streams with open canopy will exhibit more complex benthic macroinvertebrate communities (in terms of information embedded in the organisms' biomass); (3) in streams with open canopy benthic macroinvertebrate assemblages will be more efficient in using the available resources to build structure, which will be reflected by higher eco-exergy values; (4) benthic assemblages in streams with open canopy will exhibit more secondary productivity. We selected eight non-impacted headwater streams, four shaded and four with open canopy, all located in the Neotropical savannah (Cerrado) of southeastern Brazil. Open canopy streams consistently exhibited significantly higher eco-exergy and instant secondary production values, exemplifying that these streams may support more complex and productive benthic macroinvertebrate assemblages. Nevertheless, diversity indices and specific eco-exergy were not significantly different in shaded and open canopy streams. Since all the studied streams were selected for being considered as non-impacted, this suggests that the potential represented by more available food resources was not used to build a more complex dissipative structure. These results illustrate the role and importance of the canopy cover characteristics on the structure and functioning of benthic macroinvertebrate assemblages in tropical headwater streams, while autochthonous production appears to play a crucial role as food

  4. Using macroinvertebrate assemblages and multiple stressors to infer urban stream system condition: A case study in the central US

    Science.gov (United States)

    Nichols, John W.; Hubbart, Jason A.; Poulton, Barry C.

    2016-01-01

    Characterizing the impacts of hydrologic alterations, pollutants, and habitat degradation on macroinvertebrate species assemblages is of critical value for managers wishing to categorize stream ecosystem condition. A combination of approaches including trait-based metrics and traditional bioassessments provides greater information, particularly in anthropogenic stream ecosystems where traditional approaches can be confounded by variously interacting land use impacts. Macroinvertebrates were collected from two rural and three urban nested study sites in central Missouri, USA during the spring and fall seasons of 2011. Land use responses of conventional taxonomic and trait-based metrics were compared to streamflow indices, physical habitat metrics, and water quality indices. Results show that biotic index was significantly different (p habitats in urban reaches contained 21 % more (p = 0.03) multivoltine organisms, which was positively correlated to the magnitude of peak flows (r2 = 0.91, p = 0.012) suggesting that high flow events may serve as a disturbance in those areas. Results support the use of macroinvertebrate assemblages and multiple stressors to characterize urban stream system condition and highlight the need to better understand the complex interactions of trait-based metrics and anthropogenic aquatic ecosystem stressors.

  5. Combined effects of water stress and pollution on macroinvertebrate and fish assemblages in a Mediterranean intermittent river.

    Science.gov (United States)

    Kalogianni, Eleni; Vourka, Aikaterini; Karaouzas, Ioannis; Vardakas, Leonidas; Laschou, Sofia; Skoulikidis, Nikolaos Th

    2017-12-15

    Water stress is a key stressor in Mediterranean intermittent rivers exacerbating the negative effects of other stressors, such as pollutants, with multiple effects on different river biota. The current study aimed to determine the response of macroinvertebrate and fish assemblages to instream habitat and water chemistry, at the microhabitat scale and at different levels of water stress and pollution, in an intermittent Mediterranean river. Sampling was conducted at high and low summer discharge, at two consecutive years, and included four reaches that were targeted for their different levels of water stress and pollution. Overall, the macroinvertebrate fauna of Evrotas River indicated high resilience to intermittency, however, variation in community structure and composition occurred under acute water stress, due to habitat alteration and change in water physico-chemistry, i.e. water temperature increase. The combined effects of pollution and high water stress had, however, pronounced effects on species richness, abundance and community structure in the pollution impacted reach, where pollution sensitive taxa were almost extirpated. Fish response to drought, in reaches free of pollution, consisted of an increase in the abundance of the two small limnophilic species, coupled with their shift to faster flowing riffle habitats, and a reduction in the abundance of the larger, rheophilic species. In the pollution impacted reach, however, the combination of pollution and high water stress led to hypoxic conditions assumed to be the leading cause of the almost complete elimination of the fish assemblage. In contrast, the perennial Evrotas reaches with relatively stable physicochemical conditions, though affected hydrologically by drought, appear to function as refugia for fish during high water stress. When comparing the response of the two biotic groups to combined acute water stress and pollution, it is evident that macroinvertebrates were negatively impacted, but fish

  6. [Effects of cascading hydropower dams operation on the structure and distribution pattern of benthic macroinvertebrate assemblages in Manwan Reservoir, Southwest China].

    Science.gov (United States)

    Li, Jin Peng; Dong, Shi Kui; Peng, Ming Chun; Wu, Xuan; Zhou, Fang; Yu, Yin

    2017-12-01

    Benthic macroinvertebrate assemblages are one of the biological groups in aquatic ecosystem most sensitive to the habitat change and degradation, and can be a biological indicator for the aquatic ecosystem change and succession in cascading hydropower dam reservoir. The middle and lower reaches of the Lancang River are key spot for international biodiversity conservation and ecological studies on the effects of cascading hydropower dam exploitation. In this study, the reservoir of Manwan hydropower dam, the first dam in Lancang-Mekong river main stream, was selected as the study site. The benthic macroinvertebrate assemblages were sampled in 2011 and 2016 respectively. Meanwhile, the survey data before impounding (natural river, 1996) and early stage of single dam (1997) were collected to conduct the overall analysis for structure, distribution pattern and evolution of benthic macroinvertebrate assemblages. The results showed that the dominant biological group was gradually changed from the Oligochaeta and Insecta to the Mollusca. Along the longitudinal gradient, the density and biomass of the benthic macroinvertebrate assemblages were remarkably increased in reservoir, especially in the lacustrine zone. As for the functional feeding group, the predator and gatherer-collector changed into filter-collector predominantly in lacustrine zone. With the cascading dams operation, the biotic index indicated that the water quality of reservoir in 2016 was better than in 2011. The evolution of benthic macroinvertebrate assemblages in the Manwan Reservoir was related to the operation of Xiaowan dam in the upper reach, the hydrological regime and siltation in the reservoir, and would continue with dynamic changes with the operation of the cascading hydropower dam.

  7. Terrestrial and Aquatic Macroinvertebrate Assemblages as a Function of Wetland Type across a Mountain Landscape

    OpenAIRE

    Holmquist, Jeffrey G; Jones, Jennifer R; Schmidt-Gengenbach, Jutta; Pierotti, Lyra F; Love, Jason P

    2011-01-01

    Fens and wet meadows are important mountain wetland types, but influences onassemblage structure of associated invertebrates are poorly understood compared with other aspects of the ecology of these habitats. We sought to determine the relative contributions of terrestrial and aquatic invertebrates to diversity and abundance in these wetlands, the extent to which terrestrial and aquatic invertebrate assemblages differ with wetland type, and to what degree the aquatic assemblages vary as a fun...

  8. Benthic macroinvertebrate assemblages and sediment toxicity testing in the Ely Creek watershed restoration project

    International Nuclear Information System (INIS)

    Soucek, D.J.; Currie, R.J.; Cherry, D.S.; Latimer, H.A.

    1998-01-01

    The Ely Creek watershed in Lee County, Virginia, contains an abundance of abandoned mined land (AML) seeps that contaminate the majority of the creek and its confluence into Big Stone Creek. Contaminated sediments had high concentrations of iron (∼10,000 mg/kg), aluminum (∼1,500 mg/kg), magnesium (∼400 mg/kg) and manganese (∼150 mg/kg). Copper and zinc generally ranged from 3 to 20 mg/kg. Benthic macroinvertebrates surveys at six of 20 sites sampled in the watershed yielded no macroinvertebrates, while eight others had total abundances of 1 to 9 organisms. Four reference sites contained ≥100 organisms and at least 14 different taxa. Laboratory, 10-day survival/impairment sediments tests with Daphnia magna did not support the field data. Mortality of 92 to 100% for D. magna occurred in samples collected from six cities. Daphnid reproduction was more sensitive than laboratory test organism survivorship; however, neither daphnid survivorship nor reproduction were good predictors of taxa richness. Laboratory test concerns included the use of a reference diluent water rather than site specific diluent water

  9. Effects of agricultural and urban impacts on macroinvertebrates assemblages in streams (Rio Grande do Sul, Brazil

    Directory of Open Access Journals (Sweden)

    Luiz Ubiratan Hepp

    2010-02-01

    Full Text Available This study evaluates the effects of agricultural and urban activities on the structure and composition of benthic communities of streams in the state of Rio Grande do Sul, Brazil. Benthic macroinvertebrates were collected in streams influenced by urbanization and agriculture and in streams with no anthropogenic disturbances (reference streams. Organism density was superior in urban streams when compared with streams in the other two areas. The taxonomic richness and Shannon diversity index were higher in reference streams. The benthic fauna composition was significantly different among land uses. The classification and ordination analyses corroborated the results of variance analyses demonstrating the formation of clusters corresponding to streams with similar land use. Seasonality was also found to influence the benthic community, though in a lesser degree than land use.

  10. Distribution and diversity of aquatic macroinvertebrate assemblages in a semi-arid region earmarked for shale gas exploration (Eastern Cape Karoo, South Africa.

    Directory of Open Access Journals (Sweden)

    Annah Mabidi

    Full Text Available This study aims to investigate macroinvertebrate assemblage structure and composition across the three major waterbody types (temporary rivers, depression wetlands and semi-permanent dams of the Eastern Cape Karoo, and to identify important environmental and spatial correlates of macroinvertebrate assemblage composition in the region. A total of 33 waterbodies (9 dams, 13 depression wetlands and 11 rivers were sampled. Altogether, 91 taxa were recorded in November 2014 and 82 in April 2015. Twenty-seven taxa were common to all three waterbody types (across both sampling occasions, with 17 of these observed in November and 19 in April. The ANOSIM tests revealed significant differences in assemblage composition between the depression wetlands and rivers for both sampling occasions, but dams did not differ from the other waterbody types. SIMPER analyses indicated that the notonectid Anisops varia and the corixid Micronecta scutellaris were abundant across all three waterbody types during both sampling occasions. The mayfly Cloeon africanum and the damselfly Pseudagrion sp. were abundant in river habitats during both sampling occasions, while the gastropod mollusc Bulinus tropicus and the copepod Lovenula falcifera best characterised depression wetlands on both occasions. Non-metric multidimensional scaling ordination highlighted a clear separation of assemblages between November and April, while distance-based Redundancy Analysis revealed that conductivity, altitude, turbidity and pH were the most important variables explaining the variation in macroinvertebrate assemblage patterns. These results provide baseline information which is important for future biological monitoring of impacts associated with hydraulic fracturing activities and climatic changes in the region.

  11. The role of the hydrological cycle on the temporal patterns of macroinvertebrate assemblages in an Andean foothill stream in Colombia

    Directory of Open Access Journals (Sweden)

    María I. Ríos-Pulgarín

    2016-03-01

    Full Text Available The seasonal and interannual changes in the structure, composition and functional feeding groups of the macroinvertebrate assemblage of the Guarinó River, a torrential system located in the Colombian Andean foothills, were examined in relation to the physical and chemical environmental changes associated with the hydrological cycle and the El Niño-Niña/Southern Oscillation (ENSO between 2007 and 2010. Benthic samples were collected at three sites in the lower sections of the river. A total of 127 taxa were collected in the study, with the total taxonomic richness per site ranging from 82 to 96 taxa and benthos density averaging 5.41 ind. m-2. The density showed a tendency to decrease in periods of maximum river level and flow, particularly during La Niña phenomena, and to increase in dry periods, especially in the third year (2009-2010 during El Niño phenomena. The presence and abundance of taxa, functional feeding groups and life habits were regulated by environmental parameters associated with hydrological variability, derived of ENSO phenomena, especially flow rate values. The assemblage showed high taxonomic and functional diversity, which is characteristic of ecosystems affected by recurrent hydrological disturbances, exhibiting differentiated responses based on adaptive strategies against the local hydrologic regime that allow fast recovery under conditions like ENSO phenomena. Such responses include composition changes according to adaptations to different hydrological scenarios, the predominance of generalist trophic guilds and taxa with plasticity in their habits and range of environmental tolerance.

  12. SPATIO-TEMPORAL VARIATIONS IN MACROINVERTEBRATE ASSEMBLAGES OF NEW CALEDONIAN STREAMS.

    Directory of Open Access Journals (Sweden)

    MARY N. J.

    2002-01-01

    Full Text Available Forty-one sites located on 14 New Caledonian streams were surveyed four times between October 1996 and October 1997 in order to examine the spatial and temporal changes in the structure of the benthic macroinvertebrate communities. About 250 000 invertebrates representing 167 taxa were collected in the streams. Seventy-five percent of identified taxa and 67% of individuals were insects. Major spatial and temporal changes in the composition of the fauna were detected by multivariate analyses (ordination and classification. Overall, the number of individuals was significantly higher in the dry season (October than in the wetter seasons (January and June. However, a low temporal variability was detected in the structure of benthic communities during the sampling period. A cluster analysis based on taxonomic composition separated five groups of sites in relation with rock type, land use, and geographic characteristics. Several metrics (total invertebrate density, taxon richness, relative abundance of major invertebrate groups, diversity indices were used to characterize each group of sites. Forested streams, where the highest specific diversity occurred, represented the most speciose habitat for benthic fauna. A less rich and abundant fauna occurred in streams draining ultramafic rocks probably because of their low content in food resources and organic matter.

  13. Response of benthic macroinvertebrate assemblages to round (Neogobius melanostomus, Pallas 1814) and tubenose (Proterorhinus semilunaris, Heckel 1837) goby predation pressure

    Czech Academy of Sciences Publication Activity Database

    Mikl, Libor; Adámek, Zdeněk; Všetičková, Lucie; Janáč, Michal; Roche, Kevin Francis; Šlapanský, Luděk; Jurajda, Pavel

    2017-01-01

    Roč. 785, č. 1 (2017), s. 219-232 ISSN 0018-8158 R&D Projects: GA ČR(CZ) GAP505/11/1768 Institutional support: RVO:68081766 Keywords : Invasive species * Gobies * Macroinvertebrates * Impact * European rivers * Diet Subject RIV: EH - Ecology, Behaviour OBOR OECD: Marine biology, freshwater biology, limnology Impact factor: 2.056, year: 2016

  14. Investigating the influence of heavy metals on macro-invertebrate assemblages using Partial Cononical Correspondence Analysis (pCCA)

    Science.gov (United States)

    Beasley, Gary; Kneale, Pauline E.

    This paper defines the spectrum of impairment to stream macroinvertebrates arising from urban runoff. Field sampling of stream sediments at 62 sites across Yorkshire, UK was used to investigate the influence of heavy metals and habitat on macroinvertebrate family distribution using partial Canonical Correspondence Analysis (pCCA). Increasing urbanization and trafficking was associated with increasing levels of metal pollution but, even when traffic is light, family numbers can be reduced by 50%. Industrial areas and motorway runoff depress macroinvertebrate numbers but drainage from streets with no off-road parking in residential areas can have similar impacts. The heavy metals in the sediment accounted for approximately 24% of the variation in macroinvertebrate community composition while the physical habitat variables used in RIVPACS (River InVertebrate Prediction And Classification System) (Wright, 2000) accounted for an additional 30%. Zinc and nickel were the main metal influences regardless of the time of sampling; at these sites copper is less than critical. Results agree with those reported in other studies in which families mainly from the orders Ephemeroptera (mayfly), Plecoptera (stonefly) and Tricoptera (caddisfly) displayed metal sensitivity in that they were absent from metal polluted streams. However, within each of these orders, a continuum of sensitivity is evident: this highlights the risks of generalising on orders rather than using family or indeed species data.

  15. Biological assessment of aquaculture effects on effluent-receiving streams in Ghana using structural and functional composition of fish and macroinvertebrate assemblages.

    Science.gov (United States)

    Ansah, Yaw Boamah; Frimpong, Emmanuel A; Amisah, Stephen

    2012-07-01

    Biological assessment of aquatic ecosystems is widely employed as an alternative or complement to chemical and toxicity testing due to numerous advantages of using biota to determine ecosystem condition. These advantages, especially to developing countries, include the relatively low cost and technical requirements. This study was conducted to determine the biological impacts of aquaculture operations on effluent-receiving streams in the Ashanti Region of Ghana. We collected water, fish and benthic macroinvertebrate samples from 12 aquaculture effluent-receiving streams upstream and downstream of fish farms and 12 reference streams between May and August of 2009, and then calculated structural and functional metrics for biotic assemblages. Fish species with non-guarding mode of reproduction were more abundant in reference streams than downstream (P = 0.0214) and upstream (P = 0.0251), and sand-detritus spawning fish were less predominant in reference stream than upstream (P = 0.0222) and marginally less in downstream locations (P = 0.0539). A possible subsidy-stress response of macroinvertebrate family richness and abundance was also observed, with nutrient (nitrogen) augmentation from aquaculture and other farming activities likely. Generally, there were no, or only marginal differences among locations downstream and upstream of fish farms and in reference streams in terms of several other biotic metrics considered. Therefore, the scale of impact in the future will depend not only on the management of nutrient augmentation from pond effluents, but also on the consideration of nutrient discharges from other industries like fruit and vegetable farming within the study area.

  16. L-Lake macroinvertebrate community

    Energy Technology Data Exchange (ETDEWEB)

    Specht, W.L.

    1996-06-01

    To characterize the present benthic macroinvertebrate community of L-Lake, Regions 5 and 7 of the reservoir were sampled in September 1995 at the same locations sampled in 1988 and 1989 during the L-Lake monitoring program. The macroinvertebrate community of 1995 is compared to that of 1988 and 1989. The species composition of L-Lake`s macroinvertebrate community has changed considerably since 1988-1989, due primarily to maturation of the reservoir ecosystem. L-Lake contains a reasonably diverse macroinvertebrate community that is capable of supporting higher trophic levels, including a diverse assemblage of fish species. The L-Lake macroinvertebrate community is similar to those of many other southeastern reservoirs, and there is no indication that the macroinvertebrate community is perturbed by chemical or physical stressors.

  17. L-Lake macroinvertebrate community

    International Nuclear Information System (INIS)

    Specht, W.L.

    1996-06-01

    To characterize the present benthic macroinvertebrate community of L-Lake, Regions 5 and 7 of the reservoir were sampled in September 1995 at the same locations sampled in 1988 and 1989 during the L-Lake monitoring program. The macroinvertebrate community of 1995 is compared to that of 1988 and 1989. The species composition of L-Lake's macroinvertebrate community has changed considerably since 1988-1989, due primarily to maturation of the reservoir ecosystem. L-Lake contains a reasonably diverse macroinvertebrate community that is capable of supporting higher trophic levels, including a diverse assemblage of fish species. The L-Lake macroinvertebrate community is similar to those of many other southeastern reservoirs, and there is no indication that the macroinvertebrate community is perturbed by chemical or physical stressors

  18. Effects of nutrient enrichment derived from fish farming activities on macroinvertebrate assemblages in a subtropical region of Hong Kong.

    Science.gov (United States)

    Gao, Qin-Feng; Cheung, Kwok-Leung; Cheung, Siu-Gin; Shin, Paul K S

    2005-01-01

    To study the correlation between nutrient enrichment derived from fish farming activities and changes in macrobenthic assemblages, a one-year field study was conducted in Kau Sai Bay marine fish culture zone of Hong Kong. Bimonthly sediment samples were collected at six stations: two at the fish cages, two near the boundary of the fish culture area, and two reference sites further away from the culture area. Sediment physico-chemical characteristics in terms of silt/clay fraction, moisture content, total organic carbon (TOC), total Kjeldahl nitrogen (TKN) and total phosphorus (TP) were analyzed. The macrobenthos (>0.5 mm) present in the sediment were sorted, identified and enumerated. On average, TOC, TKN and TP levels at the fish cage stations were 82.8%, 128.5% and 1315.7% higher than those at the reference stations, respectively. As a result, the N:P molar ratio was greatly reduced from 8.75 at the reference stations to 1.83 at the fish cage stations. Univariate and multivariate analyses revealed that diversity of macrofauna was significantly reduced and community structure differed at the fish cage stations relative to the reference sites. The intermediary stations near the fish culture area showed a transitional state of disturbance. Faunal diversity was negatively correlated with nutrient level, reflecting the adverse impacts of nutrient enrichment derived from fish farming activities on the benthic assemblages. Whilst in subtropical Asia-Pacific trash fish is the major feed for fish culture resulting in a higher nutrient loading and nutrient ratio accumulated in the sediment beneath the fish rafts, the effects of nutrient enrichment on macrobenthic assemblages are comparable to that in temperate waters owing to relatively high sediment metabolism rate and smaller fish culture scale in Hong Kong.

  19. Diversity patterns of temporary wetland macroinvertebrate ...

    African Journals Online (AJOL)

    Although macroinvertebrates are potentially useful for assessing the condition of temporary wetlands, little is yet known about them. Macroinvertebrate assemblages were assessed in 138 temporary wetlands in the south-western Cape, recording 126 taxa. However, predicted richness estimates were all higher than the ...

  20. Macroinvertebrate variation in endorheic depression wetlands in ...

    African Journals Online (AJOL)

    Aquatic macroinvertebrates are rarely used in wetland assessments due to their variation. However, in terms of biodiversity, these invertebrates form an important component of wetland fauna. Spatial and temporal variation of macroinvertebrate assemblages in endorheic depressions (locally referred to as 'pans') in ...

  1. Macroinvertebrate distribution and aquatic ecology in the Ruoergai (Zoige) Wetland, the Yellow River source region

    Science.gov (United States)

    Zhao, Na; Xu, Mengzhen; Li, Zhiwei; Wang, Zhaoyin; Zhou, Hanmi

    2017-09-01

    The Ruoergai (Zoige) Wetland, the largest plateau peatland in the world, is located in the Yellow River source region. The discharge of the Yellow River increases greatly after flowing through the Ruoergai Wetland. The aquatic ecosystem of the Ruoergai Wetland is crucial to the whole Yellow River basin. The Ruoergai wetland has three main kinds of water bodies: rivers, oxbow lakes, and marsh wetlands. In this study, macroinvertebrates were used as indicators to assess the aquatic ecological status because their assemblage structures indicate long-term changes in environments with high sensitivity. Field investigations were conducted in July, 2012 and in July, 2013. A total of 72 taxa of macroinvertebrates belonging to 35 families and 67 genera were sampled and identified. Insecta was the dominant group in the Ruoergai Basin. The alpha diversity of macroinvertebrates at any single sampling site was low, while the alpha diversity on a basin-wide scale was much higher. Macroinvertebrate assemblages in rivers, oxbow lakes, and marsh wetlands differ markedly. Hydrological connectivity was a primary factor causing the variance of the bio-community. The river channels had the highest alpha diversity of macroinvertebrates, followed by marsh wetlands and oxbow lakes. The density and biomass of Gastropoda, collector filterers, and scrapers increased from rivers to oxbow lakes and then to marsh wetlands. The river ecology was particular in the Ruoergai Wetland with the high beta diversity of macroinvertebrates, the low alpha diversity of macroinvertebrates, and the low taxa richness, density, and biomass of EPT (Ephemeroptera, Plecoptera, Trichoptera). To maintain high alpha diversity of macroinvertebrates macroinvertebrates in the Ruoergai Wetland, moderate connectivity of oxbow lakes and marsh wetlands with rivers and measures to control headwater erosion are both crucial.

  2. Evaluating the Response of Biological Assemblages as Potential Indicators for Restoration Measures in an Intermittent Mediterranean River

    Science.gov (United States)

    Hughes, Samantha Jane; Santos, Jose; Ferreira, Teresa; Mendes, Ana

    2010-08-01

    Bioindicators are essential for detecting environmental degradation and for assessing the success of river restoration initiatives. River restoration projects require the identification of environmental and pressure gradients that affect the river system under study and the selection of suitable indicators to assess habitat quality before, during and after restoration. We assessed the response of benthic macroinvertebrates, fish, bird and macrophyte assemblages to environmental and pressure gradients from sites situated upstream and downstream of a cofferdam on the River Odelouca, an intermittent Mediterranean river in southwest Portugal. The Odelouca will be permanently dammed in 2010. Principal Component Analyses (PCA) of environmental and pressure variables revealed that most variance was explained by environmental factors that clearly separated sites upstream and downstream of the partially built cofferdam. The pressure gradient describing physical impacts to the banks and channel as a result of land use change was less distinct. Redundancy Analysis revealed significant levels of explained variance to species distribution patterns in relation to environmental and pressure variables for all 4 biological assemblages. Partial Redundancy analyses revealed high levels of redundancy for pH between groups and that the avifauna was best associated with pressures acting upon the system. Patterns in invertebrates and fish were associated with descriptors of habitat quality, although fish distribution patterns were affected by reduced connectivity. Procrustean and RELATE (Mantel test) analyses gave broadly similar results and supported these findings. We give suggestions on the suitability of key indicator groups such as benthic macroinvertebrates and endemic fish species to assess in stream habitat quality and appropriate restoration measures, such as the release of peak flow patterns that mimic intermittent Mediterranean systems to combat habitat fragmentation and

  3. Spray drift of pesticides and stream macroinvertebrates: Experimental evidence of impacts and effectiveness of mitigation measures

    Energy Technology Data Exchange (ETDEWEB)

    Maltby, Lorraine [Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN (United Kingdom)], E-mail: l.maltby@sheffield.ac.uk; Hills, Louise [Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN (United Kingdom)

    2008-12-15

    Impoverished stream communities in agricultural landscapes have been associated with pesticide contamination, but conclusive evidence of causality is rare. We address this deficiency by adopting an experimental approach to investigate the effects of the insecticides cypermethrin and chlorpyrifos on benthic macroinvertebrates. Three treatments were established and a combination of biomarker, bioassay and biomonitoring approaches was employed to investigate, individual, population and community-level effects. Animals deployed during pesticide application had altered enzyme activity, depressed feeding rate and reduced survival, but these effects were only observed where pesticide was sprayed to the stream edge. There were no clear pesticide-related effects on macroinvertebrate community structure or on the population densities of individual species. Hence, short-term pesticide exposure did cause individual-level effects in stream macroinvertebrates, but these were not translated to effects at the population or community-level and were effectively mitigated by the adoption of a no-spray buffer zone. - Pulsed pesticide exposures via spray drift adversely affected stream invertebrates but did not cause population or community-level effects and were mitigated by no-spray buffer zones.

  4. Environmental variables measured at multiple spatial scales exert uneven influence on fish assemblages of floodplain lakes

    Science.gov (United States)

    Dembkowski, Daniel J.; Miranda, Leandro E.

    2014-01-01

    We examined the interaction between environmental variables measured at three different scales (i.e., landscape, lake, and in-lake) and fish assemblage descriptors across a range of over 50 floodplain lakes in the Mississippi Alluvial Valley of Mississippi and Arkansas. Our goal was to identify important local- and landscape-level determinants of fish assemblage structure. Relationships between fish assemblage structure and variables measured at broader scales (i.e., landscape-level and lake-level) were hypothesized to be stronger than relationships with variables measured at finer scales (i.e., in-lake variables). Results suggest that fish assemblage structure in floodplain lakes was influenced by variables operating on three different scales. However, and contrary to expectations, canonical correlations between in-lake environmental characteristics and fish assemblage structure were generally stronger than correlations between landscape-level and lake-level variables and fish assemblage structure, suggesting a hierarchy of influence. From a resource management perspective, our study suggests that landscape-level and lake-level variables may be manipulated for conservation or restoration purposes, and in-lake variables and fish assemblage structure may be used to monitor the success of such efforts.

  5. Evaluation of benthic macroinvertebrate assemblage for disturbance ...

    Indian Academy of Sciences (India)

    The Ganga River System Biotic Score (GRSbios) index was applied to determine the ecological ... plemented and today the organic river pollution is gradually ... ing the chemical status of all the surface water in Europe .... 2.2 Sampling sites and approach. In total ...... an Integration of Engineering, Design and Management.

  6. Predicted macroinvertebrate response to water diversion from a montane stream using two-dimensional hydrodynamic models and zero flow approximation

    Science.gov (United States)

    Holmquist, Jeffrey G.; Waddle, Terry J.

    2013-01-01

    We used two-dimensional hydrodynamic models for the assessment of water diversion effects on benthic macroinvertebrates and associated habitat in a montane stream in Yosemite National Park, Sierra Nevada Mountains, CA, USA. We sampled the macroinvertebrate assemblage via Surber sampling, recorded detailed measurements of bed topography and flow, and coupled a two-dimensional hydrodynamic model with macroinvertebrate indicators to assess habitat across a range of low flows in 2010 and representative past years. We also made zero flow approximations to assess response of fauna to extreme conditions. The fauna of this montane reach had a higher percentage of Ephemeroptera, Plecoptera, and Trichoptera (%EPT) than might be expected given the relatively low faunal diversity of the study reach. The modeled responses of wetted area and area-weighted macroinvertebrate metrics to decreasing discharge indicated precipitous declines in metrics as flows approached zero. Changes in area-weighted metrics closely approximated patterns observed for wetted area, i.e., area-weighted invertebrate metrics contributed relatively little additional information above that yielded by wetted area alone. Loss of habitat area in this montane stream appears to be a greater threat than reductions in velocity and depth or changes in substrate, and the modeled patterns observed across years support this conclusion. Our models suggest that step function losses of wetted area may begin when discharge in the Merced falls to 0.02 m3/s; proportionally reducing diversions when this threshold is reached will likely reduce impacts in low flow years.

  7. JMorph: Software for performing rapid morphometric measurements on digital images of fossil assemblages

    Science.gov (United States)

    Lelièvre, Peter G.; Grey, Melissa

    2017-08-01

    Quantitative morphometric analyses of form are widely used in palaeontology, especially for taxonomic and evolutionary research. These analyses can involve several measurements performed on hundreds or even thousands of samples. Performing measurements of size and shape on large assemblages of macro- or microfossil samples is generally infeasible or impossible with traditional instruments such as vernier calipers. Instead, digital image processing software is required to perform measurements via suitable digital images of samples. Many software packages exist for morphometric analyses but there is not much available for the integral stage of data collection, particularly for the measurement of the outlines of samples. Some software exists to automatically detect the outline of a fossil sample from a digital image. However, automatic outline detection methods may perform inadequately when samples have incomplete outlines or images contain poor contrast between the sample and staging background. Hence, a manual digitization approach may be the only option. We are not aware of any software packages that are designed specifically for efficient digital measurement of fossil assemblages with numerous samples, especially for the purposes of manual outline analysis. Throughout several previous studies, we have developed a new software tool, JMorph, that is custom-built for that task. JMorph provides the means to perform many different types of measurements, which we describe in this manuscript. We focus on JMorph's ability to rapidly and accurately digitize the outlines of fossils. JMorph is freely available from the authors.

  8. The Relative Influence of Catchment and Site Variabbles on Fish and Macroinvertebrate Richness in Cerrado Biome Streams

    Science.gov (United States)

    Landscape and site-scale data aid the interpretation of biological data and management alternatives. We evaluated how three classes of environmental variables (natural landscape, anthropogenic pressures, and local physical habitat), influence fish and macroinvertebrate assemblage...

  9. Assessment tools for urban catchments: developing biological indicators based on benthic macroinvertebrates

    Science.gov (United States)

    Purcell, A.H.; Bressler, D.W.; Paul, M.J.; Barbour, M.T.; Rankin, E.T.; Carter, J.L.; Resh, V.H.

    2009-01-01

    Biological indicators, particularly benthic macroinvertebrates, are widely used and effective measures of the impact of urbanization on stream ecosystems. A multimetric biological index of urbanization was developed using a large benthic macroinvertebrate dataset (n = 1,835) from the Baltimore, Maryland, metropolitan area and then validated with datasets from Cleveland, Ohio (n = 79); San Jose, California (n = 85); and a different subset of the Baltimore data (n = 85). The biological metrics used to develop the multimetric index were selected using several criteria and were required to represent ecological attributes of macroinvertebrate assemblages including taxonomic composition and richness (number of taxa in the insect orders of Ephemeroptera, Plecoptera, and Trichoptera), functional feeding group (number of taxa designated as filterers), and habit (percent of individuals which cling to the substrate). Quantile regression was used to select metrics and characterize the relationship between the final biological index and an urban gradient (composed of population density, road density, and urban land use). Although more complex biological indices exist, this simplified multimetric index showed a consistent relationship between biological indicators and urban conditions (as measured by quantile regression) in three climatic regions of the United States and can serve as an assessment tool for environmental managers to prioritize urban stream sites for restoration and protection.

  10. A Benthic Macroinvertebrate Multimetric Index for Assessment of the Ecological Integrity of Northeast Streams, Thailand

    Directory of Open Access Journals (Sweden)

    Nantiya Rattanachan

    2016-07-01

    Full Text Available This study aims to develop a benthic macroinvertebrate multimetric index for assessing the ecological quality of streams in Northeastern Thailand. ANOSIM indicated that the benthic macroinvertebrate assemblage in both of each basin and each season were not significantly different (R = 0.09, p = 0.24 and R = 0.07, p = 0.35, respectively. The efficacy metrics of each basin consisting of the Mekong II, the Chi, and the Mun basins were integrated and calibrated. A total of 255 data sets of water physico-chemical and benthic macroinvertebrates during the dry period (cool and hot seasons were obtained. The stream classification could be divided into three groups: the reference group (48 stations, the stressed group (42 stations, and the intermediate group (165 stations. Twelve out of 56 metrics have been considered as a core metric for the development of a biological index for quality streams in the Northeast, including Total taxa, EPT taxa, Ephemeroptera taxa, Coleoptera taxa, % EPT, % Chironomidae, % Tolerant individuals, % Intolerant individuals, Beck's index, HBI, Predator taxa, and Clinger taxa. Moreover, this metric set covered the structure and function of organisms including the diversity of species, community structure, tolerance/intolerance measures, functional feeding group, and habit. From the efficacy validation of the biological index, the results of stream assessment corresponded to the classification sites with the physico-chemical characteristics.

  11. Water quality in Danube Delta Lakes: An assessment using benthic macroinvertebrates community

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    IBRAM Orhan

    2016-12-01

    Full Text Available An assessment of the ecological status of selected lakes in the Danube Delta Biosphere Reserve was done based on temporal and spatial variation of macroinvertebrate communities during 2012 and 2013. Macroinvertebrate communities and measures of these communities were evaluated and a baseline characterization of assemblages was determined for the analyzed sites. Each year, three sampling campaigns, one for each ice-free season were organized for data collection. Macroinvertebrate samples have been collected in every lake from three different stations with the use of an Ekmann dredge. The highest taxa richness are recorded in Fortuna and Isac lakes in 2013. Total abundance followed a pattern similar to taxa number with Fortuna and Isac lakes having the highest yearly values (maximum number of individuals – 225 - per sample has been recorded in September 2013, in Isac Lake.Using saprobic index as an indicator of ecological status Isac lake was classifies as moderate and other three lakes, Merhei, Furtuna and Rosu as good ecological status. Lack of correlation between diversity indices and the saprobic values suggests that other assessment methods could be more effective and provide better information than saprobic index does at least for Danube Delta.

  12. Assessing the performance of macroinvertebrate metrics in the Challhuaco-Ñireco System (Northern Patagonia, Argentina

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    Melina Mauad

    2015-09-01

    Full Text Available ABSTRACT Seven sites were examined in the Challhuaco-Ñireco system, located in the reserve of the Nahuel Huapi National Park, however part of the catchment is urbanized, being San Carlos de Bariloche (150,000 inhabitants placed in the lower part of the basin. Physico-chemical variables were measured and benthic macroinvertebrates were collected during three consecutive years at seven sites from the headwater to the river outlet. Sites near the source of the river were characterised by Plecoptera, Ephemeroptera, Trichoptera and Diptera, whereas sites close to the river mouth were dominated by Diptera, Oligochaeta and Mollusca. Regarding functional feeding groups, collector-gatherers were dominant at all sites and this pattern was consistent among years. Ordination Analysis (RDA revealed that species assemblages distribution responded to the climatic and topographic gradient (temperature and elevation, but also were associated with variables related to human impact (conductivity, nitrate and phosphate contents. Species assemblages at headwaters were mostly represented by sensitive insects, whereas tolerant taxa such as Tubificidae, Lumbriculidae, Chironomidae and crustacean Aegla sp. were dominant at urbanised sites. Regarding macroinvertebrate metrics employed, total richness, EPT taxa, Shannon diversity index and Biotic Monitoring Patagonian Stream index resulted fairly consistent and evidenced different levels of disturbances at the stream, meaning that this measures are suitable for evaluation of the status of Patagonian mountain streams.

  13. Functional diversity of macrobenthic assemblages decreases in response to sewage discharges

    NARCIS (Netherlands)

    Gusmao, Joao B.; Brauko, Kalina M.; Eriksson, Britas K.; Lana, Paulo C.

    We analyzed the effects of sewage discharge on a subtropical estuary by comparing the functional diversity of intertidal macroinvertebrate assemblages in contaminated with non-contaminated reference areas. Functional structure was assessed using biological traits analysis (BTA) and four multivariate

  14. Congruence in demersal fish, macroinvertebrate, and macroalgal community turnover on shallow temperate reefs.

    Science.gov (United States)

    Thomson, Russell J; Hill, Nicole A; Leaper, Rebecca; Ellis, Nick; Pitcher, C Roland; Barrett, Neville S; Edgar, Graham J

    2014-03-01

    To support coastal planning through improved understanding of patterns of biotic and abiotic surrogacy at broad scales, we used gradient forest modeling (GFM) to analyze and predict spatial patterns of compositional turnover of demersal fishes, macroinvertebrates, and macroalgae on shallow, temperate Australian reefs. Predictive models were first developed using environmental surrogates with estimates of prediction uncertainty, and then the efficacy of the three assemblages as biosurrogates for each other was assessed. Data from underwater visual surveys of subtidal rocky reefs were collected from the southeastern coastline of continental Australia (including South Australia and Victoria) and the northern coastline of Tasmania. These data were combined with 0.01 degree-resolution gridded environmental variables to develop statistical models of compositional turnover (beta diversity) using GFM. GFM extends the machine learning, ensemble tree-based method of random forests (RF), to allow the simultaneous modeling of multiple taxa. The models were used to generate predictions of compositional turnover for each of the three assemblages within unsurveyed areas across the 6600 km of coastline in the region of interest. The most important predictor for all three assemblages was variability in sea surface temperature (measured as standard deviation from measures taken interannually). Spatial predictions of compositional turnover within unsurveyed areas across the region of interest were remarkably congruent across the three taxa. However, the greatest uncertainty in these predictions varied in location among the different assemblages. Pairwise congruency comparisons of observed and predicted turnover among the three assemblages showed that invertebrate and macroalgal biodiversity were most similar, followed by fishes and macroalgae, and lastly fishes and invertebrate biodiversity, suggesting that of the three assemblages, macroalgae would make the best biosurrogate for

  15. Seagrass epiphytic assemblages are strong indicators of agricultural discharge but weak indicators of host features

    Science.gov (United States)

    Prado, Patricia

    2018-05-01

    Wastewater pulses from rice agriculture are persistently discharged into the northern shore of the Alfacs Bay (Ebro Delta, NW Mediterranean) from April to November. The bay also receives water from coastal lagoons which are subjected to freshwater inputs from the Ebro River mixed to an unknown extent with agricultural wastewater during the same period. This paper compares epiphyte assemblages growing on leaves of Cymodocea nodosa in sites exposed to agricultural drainage channels, lagoon connection channels, and control sites in the Ebro Delta Natural Park (southern shore of the bay). Leaf epiphytic assemblages of Zostera noltii patches in the northern shore of the bay were also compared with those of adjacent beds of C. nodosa. Drainage channel sites had consistently distinctive assemblages (higher species richness, biomass load, and taxa composition) than control sites. Assemblages from lagoon channel sites were more variable, with three sites showing particularly high covers of epiphytic algae and two sites more similar to controls. Epiphyte patterns clearly matched in situ measures of nutrient availability, and were consistent with decreased shoot densities in discharge sites. In contrast, differences in epiphyte assemblages between seagrass species were minor, and mostly a result of higher epiphytic loads on C. nodosa than on Z. noltii, which features thinner leaves. Further research is needed to investigate the consequences of these plant and epiphyte alterations in important ecosystem processes such as decomposition and export rates, as well as overall effects of nutrients and salinity in secondary producers such as associated macroinvertebrate assemblages supporting locally important marine fisheries.

  16. Quantification of environment-driven changes in epiphytic macroinvertebrate communities associated to Phragmites australis

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    Miguel CAÑEDO-ARGÜELLES

    2009-08-01

    Full Text Available The epiphytic macroinvertebrate communities associated with the Common Reed, Phragmites australis (Cav. Trin. ex Steudel, were examined seasonally from summer 2004 to spring 2005 in eleven coastal lagoons of the Llobregat Delta (NE Spain following the method proposed by Kornijów & Kairesalo (1994. The aims of the study were to: 1 characterise and quantify changes in epiphytic macroinvertebrate communities along environmental gradients; 2 assess the contribution of elements of the epiphytic compartment to structuring the community; 3 define the optima and tolerances of selected epiphytic macroinvertebrate taxa for the most relevant ecological factors responsible for assemblage composition; and 4 identify possible epiphytic species assemblages that would allow a lagoon’s typology to be established, as well as their representative indicator species. Communities showed statistically significant seasonal variation, with two faunal peaks: one in summer, with high chironomid densities, and the other in winter, with high naidid densities. These peaks showed a clear response to the influence of environmental factors. Salinity explained the highest percentage of total variance (36%, while trophic variables (nutrients, phytoplanktonic chlorophyll-a, and total organic carbon and epiphyton biomass (19.2 and 4% of total variance explained, respectively were secondary. Three different epiphytic macroinvertebrate species assemblages could be defined. These assemblages were directly linked to conductivity conditions, which determined the rate of survival of certain taxa, and to the existence of a direct connection with the sea, which permitted the establishment of "brackish-water" species. In spite of the existence of these species assemblages, the species composition and biomass of epiphytic macroinvertebrates and epiphyton differed substantially between lagoons; both elements were subject to changes in the environment, which finally determined the site

  17. Patrones de distribución espacial de ensambles de macroinvertebrados bentónicos de un sistema fluvial Andino Patagónico Spatial distribution patterns of benthic macroinvertebrates assemblages in an Andean Patagonian fluvial system

    Directory of Open Access Journals (Sweden)

    CAROLINA MOYA

    2009-01-01

    Full Text Available En enero de 2006 se estudiaron los patrones espaciales de distribución de comunidades de macroinvertebrados bentónicos de la cuenca hidrográfica del río Baker (45°50' O y 47°55' S y los principales factores controladores, intentando cubrir la mayor variedad de ecosistemas lóticos. Para llevar a cabo el estudio se seleccionaron 27 estaciones de muestreo ubicadas en las diferentes subcuencas del río. En cada estación se realizó una caracterización fisicoquímica del agua (conductividad, oxígeno disuelto, pH, temperatura y turbidez, y se documentaron las características del tramo de río (e.g. ancho del cauce y tipo de sedimento e información cartográfica utilizando un sistema de información geográfica (SIG. Se identificaron un total de 51 taxa que correspondieron en su mayoría a larvas de insectos (80 %. Los grupos con mayor riqueza fueron los órdenes Ephemeroptera (15 taxa, Plecoptera (8 taxa y Trichoptera (8 taxa. Los análisis de clasificación y ordenación realizados con los datos de abundancia, permitieron reconocer siete grupos de estaciones diferentes (A-F que fueron estadísticamente significativos (P In January of 2006 we studied the distributional patterns of benthic macroinvertebrate communities of the Baker river basin (45°50' O and 47°55' S and their main controlling factors trying to cover the greater variety of the lotic ecosystems. To carry out the study, 27 sampling stations were located in the different sub basins of the river. In each station, physical-chemical parameters of the column of water were quantified (conductivity, dissolved oxygen, pH, temperature and turbidity, and documented characteristics of the segment (e.g. wide of the channel and sediment type and cartographic information using a geographic information system (GIS and complemented with cartographic information using GIS. Identified a total of 51 taxa, are mostly insect larvae (80 %. The groups most richness were orders Ephemeroptera (15

  18. Influence of peak flow changes on the macroinvertebrate drift downstream of a Brazilian hydroelectric dam.

    Science.gov (United States)

    Castro, D M P; Hughes, R M; Callisto, M

    2013-11-01

    Successive daily peak flows from hydropower plants can disrupt aquatic ecosystems and alter the composition and structure of macroinvertebrates downstream. We evaluated the influence of peak flow changes on macroinvertebrate drift downstream of a hydroelectric plant as a basis for determining ecological flows that might reduce the disturbance of aquatic biota. The aim of this study was to assess the influence of flow fluctuations on the seasonal and daily drift patterns of macroinvertebrates. We collected macroinvertebrates during fixed flow rates (323 m3.s-1 in the wet season and 111 m3.s-1 in the dry season) and when peak flows fluctuated (378 to 481 m3.s-1 in the wet season, and 109 to 173 m3.s-1 in the dry season) in 2010. We collected 31,924 organisms belonging to 46 taxa in the four sampling periods. Taxonomic composition and densities of drifting invertebrates differed between fixed and fluctuating flows, in both wet and dry seasons, but family richness varied insignificantly. We conclude that macroinvertebrate assemblages downstream of dams are influenced by daily peak flow fluctuations. When making environmental flow decisions for dams, it would be wise to consider drifting macroinvertebrates because they reflect ecological changes in downstream biological assemblages.

  19. Towards stressor-specific macroinvertebrate indices: Which traits and taxonomic groups are associated with vulnerable and tolerant taxa?

    Science.gov (United States)

    Berger, Elisabeth; Haase, Peter; Schäfer, Ralf B; Sundermann, Andrea

    2018-04-01

    Monitoring of macroinvertebrate communities is frequently used to define the ecological health status of rivers. Ideally, biomonitoring should also give an indication on the major stressors acting on the macroinvertebrate communities supporting the selection of appropriate management measures. However, most indices are affected by more than one stressor. Biological traits (e.g. size, generation time, reproduction) could potentially lead to more stressor-specific indices. However, such an approach has rarely been tested. In this study we classify 324 macroinvertebrate taxa as vulnerable (decreasing abundances) or tolerant (increasing abundances) along 21 environmental gradients (i.e. nutrients, major ions, oxygen and micropollutants) from 422 monitoring sites in Germany using Threshold Indicator Taxa Analysis (TITAN). Subsequently, we investigate which biological traits and taxonomic groups are associated with taxa classified as vulnerable or tolerant with regard to specific gradients. The response of most taxa towards different gradients was similar and especially high for correlated gradients. Traits associated with vulnerable taxa across most gradients included: larval aquatic life stages, isolated cemented eggs, reproductive cycle per year macrophytes, microphytes, silt or mud and a body size >2-4cm. Our results question whether stressor-specific indices based on macroinvertebrate assemblages can be achieved using single traits, because we observed that similar taxa responded to different gradients and also similar traits were associated with vulnerable and tolerant taxa across a variety of water quality gradients. Future studies should examine whether combinations of traits focusing on specific taxonomic groups achieve higher stressor specificity. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Macroinvertebrate communities evaluated prior to and following a channel restoration project in Silver Creek, Blaine County, Idaho, 2001-16

    Science.gov (United States)

    MacCoy, Dorene E.; Short, Terry M.

    2017-11-22

    The U.S. Geological Survey, in cooperation with Blaine County and The Nature Conservancy, evaluated the status of macroinvertebrate communities prior to and following a channel restoration project in Silver Creek, Blaine County, Idaho. The objective of the evaluation was to determine whether 2014 remediation efforts to restore natural channel conditions in an impounded area of Silver Creek caused declines in local macroinvertebrate communities. Starting in 2001 and ending in 2016, macroinvertebrates were sampled every 3 years at two long-term trend sites and sampled seasonally (spring, summer, and autumn) in 2013, 2015, and 2016 at seven synoptic sites. Trend-site communities were collected from natural stream-bottom substrates to represent locally established macroinvertebrate assemblages. Synoptic site communities were sampled using artificial (multi-plate) substrates to represent recently colonized (4–6 weeks) assemblages. Statistical summaries of spatial and temporal patterns in macroinvertebrate taxonomic composition at both trend and synoptic sites were completed.The potential effect of the restoration project on resident macroinvertebrate populations was determined by comparing the following community assemblage metrics:Total taxonomic richness (taxa richness);Total macroinvertebrate abundance (total abundance);Ephemeroptera, Plecoptera, Trichoptera (EPT) richness;EPT abundance;Simpson’s diversity; andSimpson’s evenness for periods prior to and following restoration.A significant decrease in one or more metric values in the period following stream channel restoration was the basis for determining impairment to the macroinvertebrate communities in Silver Creek.Comparison of pre-restoration (2001–13) and post‑restoration (2016) macroinvertebrate community composition at trend sites determined that no significant decreases occurred in any metric parameter for communities sampled in 2016. Taxa and EPT richness of colonized assemblages at synoptic sites

  1. Are macroinvertebrates in high altitude streams affected by oxygen deficiency?

    DEFF Research Database (Denmark)

    Jacobsen, Dean; Rostgaard, S.; Vásconez, J. J.

    2003-01-01

    1. The solubility of oxygen in water increases with decreasing temperature. This has led to a general perception of cold, high mountain streams as more oxygen rich than warmer lowland streams, and that macroinvertebrates inhabiting high altitude streams have had no need to adapt to critical oxygen...... conditions. However, this fails to take into account that oxygen solubility declines with decreasing atmospheric pressure, which may be of importance at high altitudes. 2. Based on samples of macroinvertebrate benthos and in situ measurements of respiratory oxygen demand of macroinvertebrates in small...... the mean weight-specific respiratory rate of macroinvertebrates declined by only 50%, from 400 to 3800 m. We suggest that this disproportionately large gap between availability and demand of oxygen at high altitudes may imply a potential oxygen deficiency for the fauna, and we discuss how oxygen deficiency...

  2. Hydrologic controls on basin-scale distribution of benthic macroinvertebrates

    Science.gov (United States)

    Bertuzzo, E.; Ceola, S.; Singer, G. A.; Battin, T. J.; Montanari, A.; Rinaldo, A.

    2013-12-01

    The presentation deals with the role of streamflow variability on basin-scale distributions of benthic macroinvertebrates. Specifically, we present a probabilistic analysis of the impacts of the variability along the river network of relevant hydraulic variables on the density of benthic macroinvertebrate species. The relevance of this work is based on the implications of the predictability of macroinvertebrate patterns within a catchment on fluvial ecosystem health, being macroinvertebrates commonly used as sensitive indicators, and on the effects of anthropogenic activity. The analytical tools presented here outline a novel procedure of general nature aiming at a spatially-explicit quantitative assessment of how near-bed flow variability affects benthic macroinvertebrate abundance. Moving from the analytical characterization of the at-a-site probability distribution functions (pdfs) of streamflow and bottom shear stress, a spatial extension to a whole river network is performed aiming at the definition of spatial maps of streamflow and bottom shear stress. Then, bottom shear stress pdf, coupled with habitat suitability curves (e.g., empirical relations between species density and bottom shear stress) derived from field studies are used to produce maps of macroinvertebrate suitability to shear stress conditions. Thus, moving from measured hydrologic conditions, possible effects of river streamflow alterations on macroinvertebrate densities may be fairly assessed. We apply this framework to an Austrian river network, used as benchmark for the analysis, for which rainfall and streamflow time-series and river network hydraulic properties and macroinvertebrate density data are available. A comparison between observed vs "modeled" species' density in three locations along the examined river network is also presented. Although the proposed approach focuses on a single controlling factor, it shows important implications with water resources management and fluvial

  3. Land Use Influences Niche Size and the Assimilation of Resources by Benthic Macroinvertebrates in Tropical Headwater Streams.

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    Diego Marcel Parreira de Castro

    Full Text Available It is well recognized that assemblage structure of stream macroinvertebrates changes with alterations in catchment or local land use. Our objective was to understand how the trophic ecology of benthic macroinvertebrate assemblages responds to land use changes in tropical streams. We used the isotope methodology to assess how energy flow and trophic relations among macroinvertebrates were affected in environments affected by different land uses (natural cover, pasture, sugar cane plantation. Macroinvertebrates were sampled and categorized into functional feeding groups, and available trophic resources were sampled and evaluated for the isotopic composition of 13C and 15N along streams located in the Cerrado (neotropical savanna. Streams altered by pasture or sugar cane had wider and more overlapped trophic niches, which corresponded to more generalist feeding habits. In contrast, trophic groups in streams with native vegetation had narrower trophic niches with smaller overlaps, suggesting greater specialization. Pasture sites had greater ranges of resources exploited, indicating higher trophic diversity than sites with natural cover and sugar cane plantation. We conclude that agricultural land uses appears to alter the food base and shift macroinvertebrate assemblages towards more generalist feeding behaviors and greater overlap of the trophic niches.

  4. Spatial and temporal distribution of benthic macroinvertebrates in a Southeastern Brazilian river.

    Science.gov (United States)

    Silveira, M P; Buss, D F; Nessimian, J L; Baptista, D F

    2006-05-01

    Benthic macroinvertebrate assemblages are structured according to physical and chemical parameters that define microhabitats, including food supply, shelter to escape predators, and other biological parameters that influence reproductive success. The aim of this study is to investigate spatial and temporal distribution of macroinvertebrate assemblages at the Macaé river basin, in Rio de Janeiro state, Southeastern Brazil. According to the "Habitat Assessment Field Data Sheet--High Gradient Streams" (Barbour et al., 1999), the five sampling sites are considered as a reference condition. Despite the differences in hydrological parameters (mean width, depth and discharge) among sites, the physicochemical parameters and functional feeding groups' general structure were similar, except for the less impacted area, which showed more shredders. According to the Detrended Correspondence Analysis based on substrates, there is a clear distinction between pool and riffle assemblages. In fact, the riffle litter substrate had higher taxa in terms of richness and abundance, but the pool litter substrate had the greatest number of exclusive taxa. A Cluster Analysis based on sampling sites data showed that temporal variation was the main factor in structuring macroinvertebrate assemblages in the studied habitats.

  5. Evaluation of Environmental Factors to Determine the Distribution of Functional Feeding Groups of Benthic Macroinvertebrates Using an Artificial Neural Network

    NARCIS (Netherlands)

    Verdonschot, P.F.M.

    2008-01-01

    Functional feeding groups (FFGs) of benthic macroinvertebrates are guilds of invertebrate taxa that obtain food in similar ways, regardless of their taxonomic affinities. They can represent a heterogeneous assemblage of benthic fauna and may indicate disturbances of their habitats. The proportion of

  6. Aquatic macroinvertebrates and water quality in Sandia Canyon

    International Nuclear Information System (INIS)

    Bennett, K.

    1994-05-01

    In 1990, field studies of water quality and stream macroinvertebrate communities were initiated in Sandia Canyon at Los Alamos National Laboratory. The studies were designed to establish baseline data and to determine the effects of routine discharges of industrial and sanitary waste. Water quality measurements were taken and aquatic macroinvertebrates sampled at three permanent stations within the canyon. Two of the three sample stations are located where the stream regularly receives industrial and sanitary waste effluents. These stations exhibited a low diversity of macroinvertebrates and slightly degraded water quality. The last sample station, located approximately 0.4 km (0.25 mi) downstream from the nearest wastewater outfall, appears to be in a zone of recovery where water quality parameters more closely resemble those found in natural streams in the Los Alamos area. A large increase in macroinvertebrate diversity was also observed at the third station. These results indicate that effluents discharged into Sandia Canyon have a marked effect on water quality and aquatic macroinvertebrate communities

  7. Effects of Student-Induced Trampling on Aquatic Macroinvertebrates in Agricultural Headwater Streams

    Directory of Open Access Journals (Sweden)

    Jon P. Bossley

    2018-01-01

    Full Text Available Outdoor education (OE stream classes provide students with an opportunity to gain hands-on experience with sampling methods for evaluating stream water quality. Trampling by students as a result of stream classes may disrupt the substrate and negatively impact aquatic macroinvertebrates. The impact of student-induced trampling in headwaters as a result of stream classes on aquatic macroinvertebrates has not been evaluated. Our aim was to document the short-term macroinvertebrate responses to an experimental disturbance that simulated the impacts of trampling by students in riffles within small headwater streams. We measured hydrologic variables, visually estimated substrate composition and sampled aquatic macroinvertebrates within control and experimental riffles in three agricultural headwater streams in central Ohio one day prior to experimental disturbance, immediately after disturbance and one day after disturbance. Hydrologic variables and substrate type did not differ daily or between riffle types. Macroinvertebrate abundance, percentage of Ephemeroptera Plecoptera Trichoptera and percentage of Leuctridae increased after experimental disturbance, while diversity, evenness, percentage of clingers and non-metric multidimensional scaling (NMS axis 1 site scores declined after disturbance. Macroinvertebrate diversity, percent clingers and NMS axis 1 site scores were lower in experimental riffles than control riffles. None of the macroinvertebrate response variables exhibited a significant interaction effect of day × riffle type that is indicative of an effect of the experimental disturbance. Our results suggest the one-time use of an undisturbed riffle within an agricultural headwater stream for an OE stream class is not likely to impact aquatic macroinvertebrates.

  8. Fish assemblages

    Science.gov (United States)

    McGarvey, Daniel J.; Falke, Jeffrey A.; Li, Hiram W.; Li, Judith; Hauer, F. Richard; Lamberti, G.A.

    2017-01-01

    Methods to sample fishes in stream ecosystems and to analyze the raw data, focusing primarily on assemblage-level (all fish species combined) analyses, are presented in this chapter. We begin with guidance on sample site selection, permitting for fish collection, and information-gathering steps to be completed prior to conducting fieldwork. Basic sampling methods (visual surveying, electrofishing, and seining) are presented with specific instructions for estimating population sizes via visual, capture-recapture, and depletion surveys, in addition to new guidance on environmental DNA (eDNA) methods. Steps to process fish specimens in the field including the use of anesthesia and preservation of whole specimens or tissue samples (for genetic or stable isotope analysis) are also presented. Data analysis methods include characterization of size-structure within populations, estimation of species richness and diversity, and application of fish functional traits. We conclude with three advanced topics in assemblage-level analysis: multidimensional scaling (MDS), ecological networks, and loop analysis.

  9. Are the effects of an invasive crayfish on lake littoral macroinvertebrate communities consistent over time?

    Directory of Open Access Journals (Sweden)

    Ruokonen T. J.

    2016-01-01

    Full Text Available Management of invasive species requires assessment of their effects on recipient ecosystems. However, impact assessment of invasive species commonly lacks a long-term perspective which can potentially lead to false conclusions. We examined the effects of the invasive signal crayfish (Pacifastacus leniusculus Dana on the stony littoral macroinvertebrate communities of a large boreal lake and assessed the extent to which the patterns observed in previous short-term studies were stable over time. We used temporal macroinvertebrate data collected in five consecutive years from a site with a well-established crayfish population, a site with no crayfish and a site where crayfish had been recently introduced. Our results revealed that signal crayfish had temporally rather consistent negative effects on the benthic macroinvertebrate assemblages but that the effects might be limited to certain taxa, in particular Gastropoda and Coleoptera. We also observed increases in Gastropoda density and taxa richness following a decline in crayfish density, indicating that the recovery of invertebrate assemblages might be fast. Hence, negative effects on benthic macroinvertebrates can likely be minimized by effective control of the signal crayfish population.

  10. Change does not happen overnight: a case study on stream macroinvertebrates

    Directory of Open Access Journals (Sweden)

    Guareschi S.

    2016-01-01

    Full Text Available The influence of day/night conditions on individual animal/plant species has been widely studied, but diel cycle studies of the entire stream macroinvertebrate community are extremely rare. This study explored potential dissimilarities between daytime and nighttime macroinvertebrate assemblages by extensive fieldwork conducted in the Lemme stream, a natural water course of NW Italy. Here numerous structural and functional metrics (richness, abundance, biomass, indicator taxa, composition, biomonitoring values and feeding groups were evaluated at the family level. Small-scale environmental variables were investigated to understand possible differences between macroinvertebrate assemblages in the daytime/nighttime. After collecting and identifying 21 459 organisms of 50 taxa, Chironomidae (Diptera was the most abundant under both day and night conditions. Our findings stressed that similar results and biological information on daytime/nighttime data were obtained. No marked differences could be related to various factors: heterotrophic condition of small-order streams, presence of aquatic predators under night and day conditions, absence of taxa with a specific phototaxis. Of all the environmental variables, velocity was always the most important in both situations, with some differences detected in the importance of the second variable (riverbed substrate diameter. This research, and future studies on different conditions and geographic areas, will contribute knowledge on stream macroinvertebrate diel activity, and provide useful information about efficient sampling strategies.

  11. Depauperate macroinvertebrates in a mine affected stream: Clean water may be the key to recovery

    International Nuclear Information System (INIS)

    Battaglia, M.; Hose, G.C.; Turak, E.; Warden, B.

    2005-01-01

    Acid mine drainage (AMD) is frequently linked with changes in macroinvertebrate assemblages, but the relative contribution of water and sediment to toxicity is equivocal. We have shown that the macroinvertebrate fauna of Neubecks Ck, a mine impacted stream in New South Wales, Australia, was much poorer than in two reference streams. Multivariate RELATE analyses indicated that the patterns in the biological data were more strongly correlated with the concentrations of common metals in the surface water than the pore water of these streams. From this we hypothesised that the water was more toxic to the biota than the sediment and we tested this hypothesis with a sediment transplant experiment. Sediment from Neubecks Ck that was placed in reference streams retained high concentrations of metals throughout the experiment, yet supported a macroinvertebrate assemblage similar to that in the reference streams. Sediment from the reference streams that was placed in Neubecks Ck supported few, if any, animals. This indicates that water in Neubecks Ck is toxic to biota, but that sediment is able to support aquatic biota in clean water. Therefore, remediation should focus on improving water quality rather than sediment quality. - Macroinvertebrates colonise contaminated sediment in clean water

  12. Strange Assemblage

    Directory of Open Access Journals (Sweden)

    David Robert Cole

    2014-08-01

    Full Text Available This paper contends that the power of Deleuze & Guattari’s (1988 notion of assemblage as theorised in 1000 Plateaus can be normalised and reductive with reference to its application to any social-cultural context where an open system of dynamic and fluid elements are located. Rather than determining the assemblage in this way, this paper argues for an alternative conception of ‘strange assemblage’ that must be deliberately and consciously created through rigorous and focused intellectual, creative and philosophical work around what makes assemblages singular. The paper will proceed with examples of ‘strange assemblage’ taken from a film by Peter Greenaway (A Zed and 2 Noughts; the film ‘Performance’; educational research with Sudanese families in Australia; the book, Bomb Culture by Jeff Nuttall (1970; and the band Hawkwind. Fittingly, these elements are themselves chosen to demonstrate the concept of ‘strange assemblage’, and how it can be presented. How exactly the elements of a ‘strange assemblage’ come together and work in the world is unknown until they are specifically elaborated and created ‘in the moment’. Such spontaneous methodology reminds us of the 1960s ‘Happenings’, the Situationist International and Dada/Surrealism. The difference that will be opened up by this paper is that all elements of this ‘strange assemblage’ cohere in terms of a rendering of ‘the unacceptable.'

  13. Post-Disturbance Stability of Fish Assemblages Measured at Coarse Taxonomic Resolution Masks Change at Finer Scales.

    Science.gov (United States)

    Ceccarelli, Daniela M; Emslie, Michael J; Richards, Zoe T

    2016-01-01

    Quantifying changes to coral reef fish assemblages in the wake of cyclonic disturbances is challenging due to spatial variability of damage inherent in such events. Often, fish abundance appears stable at one spatial scale (e.g. reef-wide), but exhibits substantial change at finer scales (e.g. site-specific decline or increase). Taxonomic resolution also plays a role; overall stability at coarse taxonomic levels (e.g. family) may mask species-level turnover. Here we document changes to reef fish communities after severe Tropical Cyclone Ita crossed Lizard Island, Great Barrier Reef. Coral and reef fish surveys were conducted concurrently before and after the cyclone at four levels of exposure to the prevailing weather. Coral cover declined across all exposures except sheltered sites, with the largest decline at exposed sites. There was no significant overall reduction in the total density, biomass and species richness of reef fishes between 2011 and 2015, but individual fish taxa (families and species) changed in complex and unpredictable ways. For example, more families increased in density and biomass than decreased following Cyclone Ita, particularly at exposed sites whilst more fish families declined at lagoon sites even though coral cover did not decline. All sites lost biomass of several damselfish species, and at most sites there was an increase in macroinvertivores and grazers. Overall, these results suggest that the degree of change measured at coarse taxonomic levels masked high species-level turnover, although other potential explanations include that there was no impact of the storm, fish assemblages were impacted but underwent rapid recovery or that there is a time lag before the full impacts become apparent. This study confirms that in high-complexity, high diversity ecosystems such as coral reefs, species level analyses are essential to adequately capture the consequences of disturbance events.

  14. [Effects of different soil and water loss control measures on the dung beetle assemblages in Huangfuchuan watershed, Inner Mongolia of North China].

    Science.gov (United States)

    Liu, Wei; Wang, Run-Run; Liu, Xin-Min

    2013-03-01

    By using pitfall trap method, and taking the croplands and natural grasslands under different soil and water loss control measures as sampling plots, an investigation was conducted on the dung beetle assemblages in the Huangfuchuan watershed of Inner Mongolia from September 2007 to September 2008, aimed to understand the effects of different soil and water loss control measures on the dung beetle assemblages in the watershed. A total of 6169 dung beetles were captured, belonging to 15 species, 5 genus, and 2 families. The dominant species were Aphodius rectus and Onthophagus gibbulus, accounting for 66. 54% and 13. 26% of the total captured beetles, respectively. A lack of the species suitable for living in woodland habitats was the basic feature of the dung beetle assemblages. As compared with the control, all test soil and water loss control measures did not cause an obvious increase of species richness, biomass, and abundance of the dung beetle assemblages. The biomass and species richness of the assemblages as well as the abundance of the functional groups II and III had a significant negative correlation with the average tree (grass) height. Under the effects of long-term agricultural cultivation and the lack of large herbivores, the species richness and abundance of the functional group I (larger paracoprids and telocoprids) were lower than those of the functional groups II (relatively smaller paracoprids) and II (endocoprids), the main components of the dung beetle assemblages in the watershed. The faeces of the residents and livestock in the study region provided abundant foods for the dung beetle assemblages, inducing the relatively high abundance and spices richness of the assemblages occurred in the croplands nearby the villages. Our results suggested that natural grasslands were the suitable habitats for the dung beetles in Huangfuchuan watershed. At regional scale, to popularize the successful experiences of comprehensive soil and water loss control

  15. Spatial variation in lake benthic macroinvertebrate ecological assessment: a synthesis of European case studies

    DEFF Research Database (Denmark)

    Sandin, Leif Leonard; Solimini, Angelo G.

    2012-01-01

    macroinvertebrate community composition and natural and human induced environmental variables (eutrophication, catchment land-use, and hydromorphological pressures) were studied. This was done in different lake habitats (the profundal, sublittoral, and littoral) in five regions of Europe (Alpine, Northern, Central...... local invertebrate assemblages. In this issue we provide a contribution towards the understanding of basic sources of spatial variation of invertebrate assemblages in different European lake habitat types and their relationship with major human pressures. All papers have an obvious applied objective...... and our aim is to provide useful information for designing monitoring programs and invertebrate based ecological classification tools with the ultimate aim to improve a sound management of European lake ecosystems....

  16. Assessing condition of macroinvertebrate communities and sediment toxicity in the St. Lawrence River at Massena Area-of-Concern

    Science.gov (United States)

    Duffy, Brian T.; Baldigo, Barry P.; Smith, Alexander J.; George, Scott D.; David, Anthony M.

    2016-01-01

    In 1972, the USA and Canada agreed to restore the chemical, physical, and biological integrity of the Great Lakes ecosystem under the first Great Lakes Water Quality Agreement. In subsequent amendments, part of the St. Lawrence River at Massena, New York and segments of three tributaries, were designated as an Area of Concern (AOC) due to the effects of polychlorinated biphenyls (PCBs), lead and copper contamination, and habitat degradation and resulting impairment to several beneficial uses. Because sediments have been largely remediated, the present study was initiated to evaluate the current status of the benthic macroinvertebrate (benthos) beneficial use impairment (BUI). Benthic macroinvertebrate communities and sediment toxicity tests using Chironomus dilutus were used to test the hypotheses that community condition and sediment toxicity at AOC sites were not significantly different from those of adjacent reference sites. Grain size was found to be the main driver of community composition and macroinvertebrate assemblages, and bioassessment metrics did not differ significantly between AOC and reference sites of the same sediment class. Median growth of C. dilutus and its survival in three of the four river systems did not differ significantly in sediments from AOC and reference sites. Comparable macroinvertebrate assemblages and general lack of toxicity across most AOC and reference sites suggest that the quality of sediments should not significantly impair benthic macroinvertebrate communities in most sites in the St. Lawrence River AOC.

  17. Relationships among rotational and conventional grazing systems, stream channels, and macroinvertebrates

    Science.gov (United States)

    Raymond, K.L.; Vondracek, B.

    2011-01-01

    Cattle grazing in riparian areas can reduce water quality, alter stream channel characteristics, and alter fish and macroinvertebrate assemblage structure. The U.S. Department of Agriculture, Natural Resources Conservation Services has recommended Rotational Grazing (RG) as an alternative management method on livestock and dairy operations to protect riparian areas and water quality. We evaluated 13 stream channel characteristics, benthic macroinvertebrate larvae (BML), and chironomid pupal exuviae (CPE) from 18 sites in the Upper Midwest of the United States in relation to RG and conventional grazing (CG). A Biotic Composite Score comprised of several macroinvertebrate metrics was developed for both the BML assemblage and the CPE assemblage. Multi-Response Permutation Procedures (MRPP) indicated a significant difference in stream channel characteristics between RG and CG. Nonmetric Multidimensional Scaling indicated that RG sites were associated with more stable stream banks, higher quality aquatic habitat, lower soil compaction, and larger particles in the streambed. However, neither MRPP nor Mann-Whitney U tests demonstrated a difference in Biotic Composite Scores for BML or CPE along RG and CG sites. The BML and CPE metrics were significantly correlated, indicating that they were likely responding to similar variables among the study sites. Although stream channel characteristics appeared to respond to grazing management, BML and CPE may have responded to land use throughout the watershed, as well as local land use. ?? 2011 Springer Science+Business Media B.V. (outside the USA).

  18. Abundance and diversity of aquatic macroinvertebrate communities in lakes exposed to Chernobyl-derived ionising radiation

    International Nuclear Information System (INIS)

    Murphy, J.F.; Nagorskaya, L.L.; Smith, J.T.

    2011-01-01

    Littoral (lake shore) macroinvertebrate communities were studied in eight natural lakes affected by fallout from the Chernobyl accident. The lakes spanned a range in 137 Cs contamination from 100 to 15500 kBq m -2 and estimated external dose rates ranged from 0.13 to 30.7 μGy h -1 . General linear models were used to assess whether abundance of individuals, taxon richness, Berger-Parker dominance and Shannon-Wiener diversity varied across the lakes. Step-wise multiple regressions were used to relate variation in total abundance, taxon richness, Berger-Parker dominance, Shannon-Wiener diversity, taxon richness within major groups of macroinvertebrates and abundance of the more common individual taxa to the measured environmental characteristics (conductivity, pH, total hardness and phosphate; lake area, lake maximum depth and total external dose) of the lakes. No evidence was found in this study that the ecological status of lake communities has been influenced by radioactive contamination from the Chernobyl accident. Indeed, the most contaminated lake, Glubokoye, contained the highest richness of aquatic invertebrates. Taxon richness in the eight study lakes varied from 22 (Svyatskoe no. 7) to 42 (Glubokoye) which spans a range typical for uncontaminated lakes in the region. Since 90 Sr is readily-absorbed by Mollusca, estimated dose rates to this group exceeded those for other invertebrate groups in two lakes (Perstok and Glubokoye). However this study found no association between mollusc diversity or abundance of individual snail species and variation between lakes in the external radiation dose. Indeed Glubokoye, the lake most contaminated by 90 Sr, had the highest richness of freshwater snails per sample (an average of 8.9 taxa per sample). - Highlights: → We studied the effect of radiation on macroinvertebrates in Chernobyl affected lakes. → Abundance, taxon richness, Berger-Parker dominance, Shannon-Wiener diversity evaluated. → No relationship between

  19. Thermal and hydrologic responses to climate change predict marked alterations in boreal stream invertebrate assemblages.

    Science.gov (United States)

    Mustonen, Kaisa-Riikka; Mykrä, Heikki; Marttila, Hannu; Sarremejane, Romain; Veijalainen, Noora; Sippel, Kalle; Muotka, Timo; Hawkins, Charles P

    2018-06-01

    Air temperature at the northernmost latitudes is predicted to increase steeply and precipitation to become more variable by the end of the 21st century, resulting in altered thermal and hydrological regimes. We applied five climate scenarios to predict the future (2070-2100) benthic macroinvertebrate assemblages at 239 near-pristine sites across Finland (ca. 1200 km latitudinal span). We used a multitaxon distribution model with air temperature and modeled daily flow as predictors. As expected, projected air temperature increased the most in northernmost Finland. Predicted taxonomic richness also increased the most in northern Finland, congruent with the predicted northwards shift of many species' distributions. Compositional changes were predicted to be high even without changes in richness, suggesting that species replacement may be the main mechanism causing climate-induced changes in macroinvertebrate assemblages. Northern streams were predicted to lose much of the seasonality of their flow regimes, causing potentially marked changes in stream benthic assemblages. Sites with the highest loss of seasonality were predicted to support future assemblages that deviate most in compositional similarity from the present-day assemblages. Macroinvertebrate assemblages were also predicted to change more in headwaters than in larger streams, as headwaters were particularly sensitive to changes in flow patterns. Our results emphasize the importance of focusing protection and mitigation on headwater streams with high-flow seasonality because of their vulnerability to climate change. © 2018 John Wiley & Sons Ltd.

  20. The Role of Regional Factors in Structuring Ouachita Mountain Stream Assemblages

    Science.gov (United States)

    Lance R. Williams; Christopher M. Taylor; Melvin L. Warren; J. Alan Clingenpeel

    2004-01-01

    Abstract - We used Basin Area Stream Survey data from the USDA Forest Service, Ouachita National Forest to evaluate the relationship between regional fish and macroinvertebrate assemblages and environmental variability (both natural and anthropogenic). Data were collected for three years (1990-1992) from six hydrologically variable stream systems in...

  1. Macroinvetebrate Assemblages as Indicators of Water Quality of the West Seti River, Bajhang, Nepal

    Directory of Open Access Journals (Sweden)

    Mohana Matangulu

    2017-08-01

    Full Text Available Water quality of the West Seti River, a tributary of the Karnali in West Nepal was assessed using macroinvertebrates as bioindicators. The main objective of the study was to assess the ecological water quality of the West Seti River and to generate a baseline data on macroinvertebrate assemblages. The sampling was conducted during December 2015 and a total of 11 sampling sites were selected from the West Seti River and its tributaries. Qualitative samples of macroinvertebrates were collected from different habitats. Selected physico-chemical parameters such as pH and temperature were estimated on-site. Dissolved oxygen (DO was estimated by Winkler’s method. The macroinvertebrate samples were enumerated and identified up to Family level following standard literature. Chi-square test was performed to see whether macroinvertebrate taxa varied significantly along the altitudinal gradient and between the West Seti River and its tributaries. An ecological assessment tool Nepalese Biotic Score/ Average Score Per Taxon (NEPBIOS/ASPT was applied to assess the water quality of the sampling sites. The pH value ranged from 7.9 to 8.7 indicating the alkaline nature of the river. A total of 1666 individuals belonging to 34 Families and 7 Orders of macro-invertebrates were observed. The highest diversity of the macroinvertebrate taxa was observed at site T5 with nineteen Families whereas the lowest taxa diversity was observed at R3 with only five Families. The variation in macroinvertebrate assemblages between the sub-tropical and temperate zones; and the West Seti River and its tributaries were not significant. NEPBIOS/ASPT revealed a score of Water Quality Class of III-IV at Site R3 indicating that the site was polluted. This site was characterized by the abundance of red Chironomids which are considered as the indicators of organic pollution.International Journal of EnvironmentVolume-6, Issue-3, Jun-Aug 2017, page: 25-45

  2. Bioassessment of Choghakhor Wetland using Benthic Macroinvertebrates

    Directory of Open Access Journals (Sweden)

    P. Fathi

    2016-05-01

    Full Text Available In present study, besides investigating benthic communities and their demographics in Choghakhor wetland, the water quality has been evaluated and classified. Then, 10 stations were selected and sampling of benthos was done every 45 days since April 2010 to March 2011, with 3 replications at each station. Samples were obtained by Ekman grab Sampler (surface 400 cm2. The collected samples were separated and fixed by formalin (4%. The Macroinvertebrates samples were identified and counted in laboratory. Generally 25 families of benthic macroinvertebrates belonging to 5 classes and 12 orders were identified. The results were calculated as community measures, including total richness, Shannon - Wiener diversity index and Hilsenhoff Biological index at family level. The results obtained from temporal and spatial changes of data (Statgeraphics software and water qualitative classification using Shannon diversity index conformed to biological Hilsenhoff index. And finally, water quality of wetland was assessed to be polluted in average to high level. According to this study findings, it seems that, these indicators could be used as useful tools for evaluating water supplies quality.

  3. Macroinvertebrates associated with two submerged macrophytes ...

    African Journals Online (AJOL)

    Macroinvertebrates associated with two submerged macrophytes, Lagarosiphon ilicifolius and Vallisneria aethiopica , in the Sanyati Basin, Lake Kariba, Zimbabwe: effect of plant morphological complexity.

  4. [Effect of environmental factors on macroinvertebrate community structure in the Huntai River basin in the Huntai River basin].

    Science.gov (United States)

    Li, Yan-li; Li, Yan-fen; Xu, Zong-xue

    2015-01-01

    In May-June 2012, macroinvertebrates were investigated at 66 sampling sites in the Huntai River basin in Northeast of China. A total of 72 macrobenthos species were collected, of which, 51 species (70.83%) were aquatic insects, 10 species (13.89%) were mollusks, 7 species (9.72%) were annelids, and 4 species (5.56%) were arthropods. First, 13 candidate metrics (EPT taxa, Dominant taxon%, Ephemeroptera%, Trichoptera%, mollusks%, Heptageniidae/Ephemeroptera; Hydropsychidae/ Trichoptera, Oligochaeta%, intolerant taxon% , tolerant taxon%, Collector%, Clingers%, Shannon-wiener index.) which belonged to six types were chosen to represent macroinvertebrate community structure by correlation analysis. Then, relationships between anthropogenic and physiography pressures and macroinvertebrate community structure variables were measured using redundancy analysis. Then, this study compared the relative influences of anthropogenic and physiographic pressures on macroinvertebrate community structure and the relative influences of anthropogenic pressures at reach, riparian and catchment scales by pRDA. The results showed all environmental factors explained 72.23% of the variation of macroinvertebrate community structure. In addition, a large proportion of the explained variability in macroinvertebrate community structure was related to anthropogenic pressures (48.9%) and to physiographic variables (11.8%), anthropogenic pressures at reach scale influenced most significantly macroinvertebrate community structure which explained 35.3% of the variation of macroinvertebrate community structure. pH, habitat, TN, CODMn, hardness, conductivity, total dissolved particle and ammonia influenced respectively explained 4%, 3.6%, 1.8%, 1.7%, 1.7%, 0.9%, 0.9% and 0.9% of the variation of macroinvertebrate community structure. The land use at riparian and catchment scale respectively explained 10% and 7% of the variation of macroinvertebrate community structure. Finally, the relationships of

  5. Performance comparison of biotic indices measuring the ecological status base on soft-bottom macroinvertebrates: a study along the shallow Gomishan lagoon (Southeast Caspian Sea

    Directory of Open Access Journals (Sweden)

    Nabee Basatnia

    2015-12-01

    Full Text Available Abstract This paper aims to test the suitability of some biotic indices for their application in Southeast Caspian Sea. For this purpose, the ecological quality of the Gomishan lagoon was assessed using three biotic indices (AMBI, BENTIX, BOPA during summer and autumn 2010. The results from the application of the biotic indices do not highlight a clear distinction between the stations. The results show that two of the indices (AMBI and BENTIX are very close in terms of diagnosis (good and high and seem to generally perform better than BOPA. In addition, Principal Component Analysis (PCA based on abiotic parameters showed clear spatial and temporal differences in environmental variables. However, at this shallow sites with low human pressure and high water residence times, such benthic community composition can be associated with physical stress due to salinity increase and to changes in environmental characteristics, triggered by conventional seasonal variations. Natural variability of transitional waters is a crucial factor for a correct evaluation of the ecological condition of macroinvertebrate communities across the lagoonal system.

  6. Concordance between macrophytes and macroinvertebrates in a Mediterranean river of central Apennine region.

    Science.gov (United States)

    Traversetti, Lorenzo; Scalici, Massimiliano; Ginepri, Valeria; Manfrin, Alessandro; Ceschin, Simona

    2014-05-01

    The main aim of this study was to improve the knowledge about the concordance among macrophytes and macroinvertebrates to provide complementary information and facilitate the procedures for quality assessment of river ecosystems. Macrophytes and macroinvertebrates were collected in 11 sampling sites along a central Apennine calcareous river in October 2008 and June 2009. The concordance between the two biomonitoring groups was tested according to several environmental parameters. The comparison of data matrix similarities by Mantel test showed differences in the assemblage of macrophytes and macroinvertebrates along the river since correlation values were 0.04, p > 0.05 in October 2008 and 0.39, p > 0.05 in June 2009. The study revealed lack of concordance between the two groups, emphasizing that the information provided by macrophytes and macroinvertebrates does not overlap in terms of response to environmental parameters. Indeed, the two different biological groups resulted useful descriptors of different parameters. Together, they could represent a complementary tool to reflect the river environmental quality.

  7. Composition and dynamic of benthic macroinvertebrates community ...

    African Journals Online (AJOL)

    the purpose to analyze the taxonomic composition, the structure of benthic macroinvertebrates community and the composite ... differences relative to the spatial and temporal variation in the taxonomic composition. ... changes in the structure of macroinvertebrates community ... 2007) with an annual growth rate of 2.4% rely.

  8. Assessing combined impacts of agrochemicals: Aquatic macroinvertebrate population responses in outdoor mesocosms.

    Science.gov (United States)

    Barmentlo, S Henrik; Schrama, Maarten; Hunting, Ellard R; Heutink, Roel; van Bodegom, Peter M; de Snoo, Geert R; Vijver, Martina G

    2018-08-01

    Agricultural ditches host a diverse community of species. These species often are unwarrantedly exposed to fertilizers and a wide-array of pesticides (hereafter: agrochemicals). Standardized ecotoxicological research provides valuable information to predict whether these pesticides possibly pose a threat to the organisms living within these ditches, in particular macro-invertebrates. However, knowledge on how mixtures of these agrochemicals affect macro-invertebrates under realistic abiotic conditions and with population and community complexity is mostly lacking. Therefore we examined here, using a full factorial design, the population responses of macroinvertebrate species assemblages exposed to environmentally relevant concentrations of three commonly used agrochemicals (for 35days) in an outdoor experiment. The agrochemicals selected were an insecticide (imidacloprid), herbicide (terbuthylazine) and nutrients (NPK), all having a widespread usage and often detected together in watersheds. Effects on species abundance and body length caused by binary mixture combinations could be described from single substance exposure. However, when agrochemicals were applied as tertiary mixtures, as they are commonly found in agricultural waters, species' abundance often deviated from expectations made based on the three single treatments. This indicates that pesticide-mixture induced toxicity to population relevant endpoints are difficult to extrapolate to field conditions. As in agricultural ditches often a multitude (approx. up to 7) of agrochemicals residues are detected, we call other scientist to verify the ecological complexity of non-additive induced shifts in natural aquatic invertebrate populations and aquatic species assemblages. Copyright © 2018 Elsevier B.V. All rights reserved.

  9. Effect of copper on multiple successional stages of a marine fouling assemblage.

    Science.gov (United States)

    McElroy, David J; Hochuli, Dieter F; Doblin, Martina A; Murphy, Richard J; Blackburn, Robert J; Coleman, Ross A

    2017-11-01

    Copper based paints are used to prevent fouling on the hulls of ships. The widely documented effect of copper on hull assemblages may be primarily due to direct effects on the invertebrates themselves or indirect effects from copper absorbed into the microbial biofilm before settlement has commenced. Artificial units of habitat were exposed to varied regimes of copper to examine (1) the photosynthetic efficiency and pigments of early-colonising biofilms, and (2) subsequent macroinvertebrate assemblage change in response to the different regimes of copper. Macroinvertebrate assemblages were found to be less sensitive to the direct effects of copper than indirect effects as delivered through biofilms that have been historically exposed to copper, with some species more tolerant than others. This raises further concern for the efficacy of copper as a universal antifoulant on the hulls of ships, which may continue to assist the invasion of copper-tolerant invertebrate species.

  10. Macroinvertebrate community change associated with the severity of streamflow alteration

    Science.gov (United States)

    Carlisle, Daren M.; Eng, Kenny; Nelson, S.M.

    2014-01-01

    Natural streamflows play a critical role in stream ecosystems, yet quantitative relations between streamflow alteration and stream health have been elusive. One reason for this difficulty is that neither streamflow alteration nor ecological responses are measured relative to their natural expectations. We assessed macroinvertebrate community condition in 25 mountain streams representing a large gradient of streamflow alteration, which we quantified as the departure of observed flows from natural expectations. Observed flows were obtained from US Geological Survey streamgaging stations and discharge records from dams and diversion structures. During low-flow conditions in September, samples of macroinvertebrate communities were collected at each site, in addition to measures of physical habitat, water chemistry and organic matter. In general, streamflows were artificially high during summer and artificially low throughout the rest of the year. Biological condition, as measured by richness of sensitive taxa (Ephemeroptera, Plecoptera and Trichoptera) and taxonomic completeness (O/E), was strongly and negatively related to the severity of depleted flows in winter. Analyses of macroinvertebrate traits suggest that taxa losses may have been caused by thermal modification associated with streamflow alteration. Our study yielded quantitative relations between the severity of streamflow alteration and the degree of biological impairment and suggests that water management that reduces streamflows during winter months is likely to have negative effects on downstream benthic communities in Utah mountain streams. 

  11. Responses of epibenthic and nektonic macroinvertebrate communities to a gradient of fish size in ponds

    Directory of Open Access Journals (Sweden)

    Marek Nieoczym

    2014-07-01

    Full Text Available Size relationships between fish and organisms from adjacent trophic levels are crucial for predicting the structure and dynamics of aquatic ecosystems. We compared macroinvertebrate communities along a fish-size gradient created by separate stocking of three age cohorts of common carp Cyprinus carpio in semi-natural ponds. The specific size range of fish (small, medium and large corresponding to fish age in ponds was the factor most strongly associated with macroinvertebrate composition. The other significant habitat variables were dissolved oxygen concentration in the water and submerged vegetation abundance in the open-water zone. Among the most numerous taxa in the ponds, relative abundances of Hirudinea, Gastropoda, Odonata and Coleoptera were larger in the presence of small-sized than of larger-sized carp. However, fish size effect was not linear, in that macroinvertebrate assemblages were less similar between ponds containing medium- vs large-sized fish than between ponds with small- vs large-sized fish. The dissimilarity patterns were mainly determined by disparities in abundance of Corixidae, which unlike other taxa common in the ponds occurred in the greatest numbers in the presence of large-sized carp. Macroinvertebrate diversity was greatest in ponds with small-sized fish and was positively related to emergent macrophyte cover. Enhancement of emergent vegetation is recommended as the most effective management strategy to buffer adverse impacts of fish on macroinvertebrates. If fish are present in the system, assessment of the size structure of fish populations can be advantageous in unravelling the essential processes driving the variation in pond communities.

  12. Stream habitat structure influences macroinvertebrate response to pesticides

    DEFF Research Database (Denmark)

    Rasmussen, Jes; Wiberg-Larsen, Peter; Baattrup-Pedersen, Annette

    2012-01-01

    Agricultural pesticide contamination in surface waters is increasingly threatening to impair the surface water ecosystems. Agricultural streams are furthermore often heavily maintained to optimise the transport of water away from fields. The physical habitat degradation that result from heavy...... stream maintenance probably introduce additional stress that may act in concert with pesticide stress. We surveyed pesticide contamination and macroinvertebrate community structure in 14 streams along a gradient of expected pesticide exposure. A paired-reach approach was applied to differentiate...... the effects of pesticides between sites with degraded and more undisturbed physical properties. The effect of pesticides on macroinvertebrate communities (measured as the relative abundance of SPEcies At Risk) was increased at stream sites with degraded physical habitats primarily due to the absence...

  13. Macroinvertebrate community responses to gravel augmentation in a high-gradient, Southeastern regulated river

    Energy Technology Data Exchange (ETDEWEB)

    McManamay, Ryan A [ORNL; Orth, Dr. Donald J [Virginia Polytechnic Institute and State University; Dolloff, Dr. Charles A [United States Department of Agriculture (USDA), United States Forest Service (USFS) and Virginia Pol

    2013-01-01

    Sediment transport, one of the key processes of river systems, is altered or stopped by dams, leaving lower river reaches barren of sand and gravel, both of which are essential habitat for fish and macroinvertebrates. One way to compensate for losses in sediment is to supplement gravel to river reaches below impoundments. Because gravel addition has become a widespread practice, it is essential to evaluate the biotic response to restoration projects in order to improve the efficacy of future applications. The purpose of our study was to evaluate the response of the macroinvertebrate community to gravel addition in a high-gradient, regulated river in western North Carolina. We collected benthic macroinvertebrate samples from gravel-enhanced areas and unenhanced areas for 1 season before gravel addition, and for 4 seasons afterwards. Repeated measures multivariate analysis of variance indicated that the responses of macroinvertebrates to gravel addition were generally specific to individual taxa or particular functional feeding groups and did not lead to consistent patterns in overall family richness, diversity, density, or evenness. Non-metric multi-dimensional scaling showed that shifts in macroinvertebrate community composition were temporary and dependent upon site conditions and season. Correlations between macroinvertebrate response variables and substrate microhabitat variables existed with or without the inclusion of data from enhanced areas, which suggests that substrate-biotic relationships were present before gravel addition. A review of the current literature suggests that the responses of benthic macroinvertebrates to substrate restoration are inconsistent and dependent upon site conditions and the degree habitat improvement of pre-restoration site conditions.

  14. Ecological impact assessment of sediment remediation in a metal-contaminated lowland river using translocated zebra mussels and resident macroinvertebrates.

    Science.gov (United States)

    De Jonge, M; Belpaire, C; Geeraerts, C; De Cooman, W; Blust, R; Bervoets, L

    2012-12-01

    The present study investigated to what extent accumulated metal levels in aquatic invertebrates can reflect environmental contamination and how these tissue levels can be related to alterations in macroinvertebrate communities in the dredged River Dommel. Metal accumulation was measured in translocated zebra mussels (Dreissena polymorpha) and resident Chironomidae. Furthermore, macroinvertebrate community composition was assessed. Our results indicated that trends of total metal concentrations in surface water of the Dommel in time are reflected well by metal levels in tissue of D. polymorpha. In contrast, sediment-bound metals were the most dominant exposure route for Chironomidae. Alterations in macroinvertebrate community composition were observed during dredging and significant relations between metal levels in invertebrate tissues and ecological responses were found. Our results demonstrated that metal accumulation in both zebra mussels and Chironomidae can be used as an integrated measure of metal bioavailability and to predict ecological effects of metal toxicity on macroinvertebrate communities. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. The influence of connectivity in forest patches, and riparian vegetation width on stream macroinvertebrate fauna

    Directory of Open Access Journals (Sweden)

    IC Valle

    Full Text Available We assessed two dimensions of stream connectivity: longitudinal (between forest patches along the stream and lateral (riparian vegetation, using macroinvertebrate assemblages as bioindicators. Sites representing different land-uses were sampled in a lowland basin that holds a mosaic of protected areas. Land-use analysis, forest successional stages and riparian zone widths were calculated by the GIS analysis. Macroinvertebrate fauna was strongly affected by land-use. We observed a continuous decrease in the number of sensitive species, %Shredders and IBE-IOC biotic index from the upstream protected area to highly deforested sites, increasing again where the stream crosses a Biological Reserve. When analysing buffer strips, we found aquatic fauna responding to land-use alterations beyond the 30 m riparian corridor (60 m and 100 m wide. We discussed the longitudinal connectivity between forest patches and the riparian vegetation buffer strips necessary to hold high macroinvertebrate diversity. We recommend actions for the increase/maintenance of biodiversity in this and other lowland basins.

  16. Beyond classic ecological assessment: The use of functional indices to indicate fish assemblages sensitivity to human disturbance in estuaries.

    Science.gov (United States)

    Teichert, Nils; Lepage, Mario; Lobry, Jérémy

    2018-05-22

    Assessing ecological health of aquatic ecosystems is crucial in the current context of biodiversity loss to guide and prioritize management actions. Although several fish-based indices were developed to assess the ecological status of estuarine ecosystems, they do not provide guidance on the causal responses of communities to disturbances. The functional trait-based approach provides an understanding of how human disturbance affects the composition of biological and ecological traits in assemblages, as well as their consequences for ecosystem functioning. Here, we evaluate the responses of fish assemblages to human disturbance in 30 French estuaries using several taxonomic and functional indices (e.g. diversity, evenness or redundancy). We tested whether these indices can provide additional information on the human impacts and health of assemblages that are not reflected by the ecological indicator (fish-based index ELFI). Results indicated that high values of local human disturbances were associated to a decrease in fish abundance, decrease in species richness and reduced functional redundancy, whereas taxonomic and functional evenness increased. In contrast, the functional richness remained stable suggesting that the functional traits of species removed by stressors were maintained by more tolerant species. Indeed, we found that the local disturbances mainly resulted in a decrease in the proportions of small benthic species feeding on macro-invertebrates, which were dominant in the studied estuaries. Some functional alterations were detected by the fish-based index, but the decline of functional redundancy was not reflected, highlighting a serious concern for management. Indeed, the abrupt collapse of functional redundancy in response to local disturbances can decrease the ability of assemblages to maintain certain species traits in the face of future environmental disturbance, including climate change. From a management perspective, the application of such

  17. Modeling Aquatic Macroinvertebrate Richness Using Landscape Attributes

    Directory of Open Access Journals (Sweden)

    Marcia S. Meixler

    2015-01-01

    Full Text Available We used a rapid, repeatable, and inexpensive geographic information system (GIS approach to predict aquatic macroinvertebrate family richness using the landscape attributes stream gradient, riparian forest cover, and water quality. Stream segments in the Allegheny River basin were classified into eight habitat classes using these three landscape attributes. Biological databases linking macroinvertebrate families with habitat classes were developed using life habits, feeding guilds, and water quality preferences and tolerances for each family. The biological databases provided a link between fauna and habitat enabling estimation of family composition in each habitat class and hence richness predictions for each stream segment. No difference was detected between field collected and modeled predictions of macroinvertebrate families in a paired t-test. Further, predicted stream gradient, riparian forest cover, and total phosphorus, total nitrogen, and suspended sediment classifications matched observed classifications much more often than by chance alone. High gradient streams with forested riparian zones and good water quality were predicted to have the greatest macroinvertebrate family richness and changes in water quality were predicted to have the greatest impact on richness. Our findings indicate that our model can provide meaningful landscape scale macroinvertebrate family richness predictions from widely available data for use in focusing conservation planning efforts.

  18. Reach-scale stream restoration in agricultural streams of southern Minnesota alters structural and functional responses of macroinvertebrates

    Science.gov (United States)

    Dolph, Christine L.; Eggert, Susan L.; Magner, Joe; Ferrington, Leonard C.; Vondracek, Bruce C.

    2015-01-01

    Recent studies suggest that stream restoration at the reach scale may not increase stream biodiversity, raising concerns about the utility of this conservation practice. We examined whether reach-scale restoration in disturbed agricultural streams was associated with changes in macroinvertebrate community structure (total macroinvertebrate taxon richness, total macroinvertebrate density, Ephemeroptera, Plecoptera, Trichoptera [EPT] taxon richness, % abundance of EPT taxa) or secondary production (macroinvertebrate biomass over time). We collected macroinvertebrate samples over the course of 1 y from restored and unrestored reaches of 3 streams in southern Minnesota and used generalized least-square (GLS) models to assess whether measures of community structure were related to reach type, stream site, or sampling month. After accounting for effects of stream site and time, we found no significant difference in total taxon richness or % abundance of EPT taxa between restored and unrestored reaches. However, the number of EPT taxa and macroinvertebrate density were significantly higher in restored than in unrestored reaches. We compared secondary production estimates among study reaches based on 95th-percentile confidence intervals generated via bootstrapping. In each study stream, secondary production was significantly (2–3×) higher in the restored than in the unrestored reach. Higher productivity in the restored reaches was largely a result of the disproportionate success of a few dominant, tolerant taxa. Our findings suggest that reach-scale restoration may have ecological effects that are not detected by measures of total taxon richness alone.

  19. Effects of watershed and in-stream liming on macroinvertebrate communities in acidified tributaries to an Adirondack lake

    Science.gov (United States)

    George, Scott D.; Baldigo, Barry P.; Lawrence, Gregory B.; Fuller, Randall L.

    2018-01-01

    Liming techniques are being explored as a means to accelerate the recovery of aquatic biota from decades of acid deposition in many regions. The preservation or restoration of native sportfish populations has typically been the impetus for liming programs, and as such, less attention has been given to its effects on other biological assemblages such as macroinvertebrates. Furthermore, the differing effects of various lime application strategies such as in-stream and watershed applications are not well understood. In 2012, a program was initiated using in-stream and aerial (whole-watershed) liming to improve water quality and Brook Trout (Salvelinus fontinalis) recruitment in three acidified tributaries of a high-elevation Adirondack lake in New York State. Concurrently, macroinvertebrates were sampled annually between 2013 and 2016 at 3 treated sites and 3 untreated reference sites to assess the effects of each liming technique on this community. Despite improvements in water chemistry in all three limed streams, our results generally suggest that neither liming technique succeeded in improving the condition of macroinvertebrate communities. The watershed application caused an immediate and unsustained decrease in the density of macroinvertebrates and increase in the proportion of sensitive taxa. These changes were driven primarily by a one-year 71 percent reduction of the acid-tolerant Leuctra stoneflies and likely represent an initial chemistry shock from the lime application rather than a recovery response. The in-stream applications appeared to reduce the density of macroinvertebrates, particularly in one stream where undissolved lime covered the natural substrate. The close proximity of our study sites to the in-stream application points (50 and 1230 m) may partly explain these negative effects. Our results are consistent with prior studies of in-stream liming which indicate that this technique often fails to restore macroinvertebrate communities to a pre

  20. Effects of acid mine drainage on water, sediment and associated benthic macroinvertebrate communities

    International Nuclear Information System (INIS)

    Rutherford, L.G.; Cherry, D.S.; Dobbs, M.G.; Cairns, J. Jr.; Zipper, C.E.

    1995-01-01

    The toxic constituents of abandoned mined land (AML) discharges (acidic pH, heavy metals, total suspended solids) are extremely toxic to aquatic life . Studies were undertaken to ascertain environmental impacts to the upper Powell River, Lee and Wise Counties, Va. These impacts included disruptions in physical water quality, sediment quality, altered benthic macroinvertebrate assemblages, and toxicity of the water column and sediments from short-term impairment bioassays, and the potential to bioaccumulate selected metals (Al, Fe, Mn, P, Zn, Cu, Mg, S, Ni, Cd) by periphyton and resident bivalves. Water chemistry and macroinvertebrate assemblages were collected at upstream control, just below acid mine drainage and other downstream sites. Selected trace metal concentrations (Al, Fe, Mn, P, Zn, Cu, Mg, S, Ni, Cd) were determined for water, sediment and resident bivalves using ICP-AES. Acidic pH ranged from 2.15--3.3 at three AML-influenced seeps and varied from 6.4--8.0 at reference stations. At one AML-influenced creek, acidic pH conditions worsened from summer to fall and eradicated aquatic life throughout a 1.5 km stretch of that creek as it flowed into another creek. An additional dilution of 3.4 km in the second creek was needed to nearly neutralize the acidic pH problem. Conductivity (umhos/cm) ranged from 32--278 at reference sites and from 245--4,180 at AML-impact sites. Benthic macroinvertebrate abundance and taxon richness were essentially eliminated in the seeps or reached numbers of 1 -3 taxa totaling < 10 organisms relative to reference areas where richness values were 12--17 and comprised 300--977 organisms. Concentrations of Fe, Al, Mg and Cu and Zn were highest in the environmentally stressed stations of low pH and high conductivity relative to the reference stations. Iron was, by far, the element in highest concentration followed by Al and Mg

  1. Benthic macroinvertebrates along the soil/water interface of the HUMEX lake 1989-1991

    Energy Technology Data Exchange (ETDEWEB)

    Hargeby, A.; Petersen, R.C. Jr.; Kullberg, A.; Svensson, M. (Univ. of Lund (Sweden))

    1992-01-01

    The taxonomic composition, abundance, and size distribution of benthic macroinvertebrates were studied at the soil/water interface two years before and the first year after the start of artificial acidification of a small catchment and its humic lake. The macroinvertebrate assemblage consisted mainly of predators; dragonflies (Odonata), damselflies (Zygoptera), net-building caddisflies (Polycentropodidae), diving beetles (Dytiscidae), and water bugs (Hemiptera). It is suggested that benthic and planktonic microcrustaceans are important prey for damselflies and that intraguild predation is important for the structure of the community. The typical bog tarn assemblage did not include snails, mussels, or macrocrustaceans, which are algae and detritus feeders known to be affected by low pH. The only potential herbivores on filaments algae and shredders of coarse detritus were case building caddisflies and the ephemeropteran Leptophlebia vespertina, which were all found in low numbers. If the artificial acidification will eliminate these macroinvertebrates, it will have little impact on attached filaments algae, and on processing of coarse detritus. Although there was a general similarity in taxonomic structure on the two sides, significantly higher numbers of dytiscids (Acilius sulcatus and Ilybius spp.) were consistently found on the experimental side than on the control side through the three years of study. The first year after acidification, the number of Zygoptera was lower on the experimental side than on the control side. The abundance on the control side in this year was, however, also higher than in the previous two years. The size distribution of Coenagrion hastulatum, the dominating zygopteran, showed no difference between lake sides. Significant difference between years indicate, however, that size distribution could be used to detect altered growth conditions. 20 refs., 5 figs., 4 tabs.

  2. Temporal changes in taxonomic and functional diversity of fish assemblages downstream from mountaintop mining

    Science.gov (United States)

    Hitt, Nathaniel P.; Chambers, Douglas B.

    2014-01-01

    Mountaintop mining (MTM) affects chemical, physical, and hydrological properties of receiving streams, but the long-term consequences for fish-assemblage structure and function are poorly understood. We sampled stream fish assemblages using electrofishing techniques in MTM exposure sites and reference sites within the Guyandotte River basin, USA, during 2010–2011. We calculated indices of taxonomic diversity (species richness, abundance, Shannon diversity) and functional diversity (functional richness, functional evenness, functional divergence) to compare exposure and reference assemblages between seasons (spring and autumn) and across years (1999–2011). We based temporal comparisons on 2 sites that were sampled during 1999–2001 by Stauffer and Ferreri (2002). Exposure assemblages had lower taxonomic and functional diversity than reference assemblages or simulated assemblages that accounted for random variation. Differences in taxonomic composition between reference and exposure assemblages were associated with conductivity and aqueous Se concentrations. Exposure assemblages had fewer species, lower abundances, and less biomass than reference assemblages across years and seasons. Green Sunfish (Lepomis cyanellus) and Creek Chub (Semotilus atromaculatus) became numerically dominant in exposure assemblages over time because of their persistence and losses of other taxa. In contrast, species richness increased over time in reference assemblages, a result that may indicate recovery from drought. Mean individual biomass increased as fish density decreased and most obligate invertivores were apparently extirpated at MTM exposure sites. Effects of MTM were not related to physical-habitat conditions but were associated with water-quality variables, which may limit quality and availability of benthic macroinvertebrate prey. Simulations revealed effects of MTM that could not be attributed to random variation in fish assemblage structure.

  3. The role of benthic microhabitats in determining the effects of hydromorphological river restoration on macroinvertebrates

    NARCIS (Netherlands)

    Verdonschot, R.C.M.; Kail, Jochem; McKie, Brendan G.; Verdonschot, P.F.M.

    2016-01-01

    Despite the large number of river restoration projects carried out worldwide, evidence for strong and long-term positive ecological effects of hydromorphological restoration on macroinvertebrates is scarce. To improve the understanding of the success and failure of restoration measures, a

  4. Microplastic effect thresholds for freshwater benthic macroinvertebrates

    NARCIS (Netherlands)

    Redondo Hasselerharm, P.E.; Dede Falahudin, Dede; Peeters, E.T.H.M.; Koelmans, A.A.

    2018-01-01

    Now that microplastics have been detected in lakes, rivers and estuaries all over the globe, evaluating their effects on biota has become an urgent research priority. This is the first study that aims at determining the effect thresholds for a battery of six freshwater benthic macroinvertebrates

  5. Ecological impact assessment of sediment remediation in a metal-contaminated lowland river using translocated zebra mussels and resident macroinvertebrates

    International Nuclear Information System (INIS)

    De Jonge, M.; Belpaire, C.; Geeraerts, C.; De Cooman, W.; Blust, R.; Bervoets, L.

    2012-01-01

    The present study investigated to what extent accumulated metal levels in aquatic invertebrates can reflect environmental contamination and how these tissue levels can be related to alterations in macroinvertebrate communities in the dredged River Dommel. Metal accumulation was measured in translocated zebra mussels (Dreissena polymorpha) and resident Chironomidae. Furthermore, macroinvertebrate community composition was assessed. Our results indicated that trends of total metal concentrations in surface water of the Dommel in time are reflected well by metal levels in tissue of D. polymorpha. In contrast, sediment-bound metals were the most dominant exposure route for Chironomidae. Alterations in macroinvertebrate community composition were observed during dredging and significant relations between metal levels in invertebrate tissues and ecological responses were found. Our results demonstrated that metal accumulation in both zebra mussels and Chironomidae can be used as an integrated measure of metal bioavailability and to predict ecological effects of metal toxicity on macroinvertebrate communities. - Highlights: ► The use of tissue concentrations to assess environmental metal pollution was studied. ► Metal accumulation was measured in caged zebra mussels and resident Chironomidae. ► Shell condition of mussels and macroinvertebrate taxa distribution was assessed. ► Different accumulation between biota and relations with community level were found. ► Bioaccumulation is an integrated measure of metal toxicity in aquatic communities. - Metal accumulation in selected aquatic invertebrates can be used as an integrated measure of metal bioavailability and to predict ecological effects of metal toxicity.

  6. Evaluation of alternative macroinvertebrate sampling techniques for use in a new tropical freshwater bioassessment scheme

    Directory of Open Access Journals (Sweden)

    Isabel Eleanor Moore

    2015-06-01

    Full Text Available Aim: The study aimed to determine the effectiveness of benthic macroinvertebrate dredge net sampling procedures as an alternative method to kick net sampling in tropical freshwater systems, specifically as an evaluation of sampling methods used in the Zambian Invertebrate Scoring System (ZISS river bioassessment scheme. Tropical freshwater ecosystems are sometimes dangerous or inaccessible to sampling teams using traditional kick-sampling methods, so identifying an alternative procedure that produces similar results is necessary in order to collect data from a wide variety of habitats.MethodsBoth kick and dredge nets were used to collect macroinvertebrate samples at 16 riverine sites in Zambia, ranging from backwaters and floodplain lagoons to fast flowing streams and rivers. The data were used to calculate ZISS, diversity (S: number of taxa present, and Average Score Per Taxon (ASPT scores per site, using the two sampling methods to compare their sampling effectiveness. Environmental parameters, namely pH, conductivity, underwater photosynthetically active radiation (PAR, temperature, alkalinity, flow, and altitude, were also recorded and used in statistical analysis. Invertebrate communities present at the sample sites were determined using multivariate procedures.ResultsAnalysis of the invertebrate community and environmental data suggested that the testing exercise was undertaken in four distinct macroinvertebrate community types, supporting at least two quite different macroinvertebrate assemblages, and showing significant differences in habitat conditions. Significant correlations were found for all three bioassessment score variables between results acquired using the two methods, with dredge-sampling normally producing lower scores than did the kick net procedures. Linear regression models were produced in order to correct each biological variable score collected by a dredge net to a score similar to that of one collected by kick net

  7. Coal-tar based pavement sealant toxicity to freshwater macroinvertebrates

    International Nuclear Information System (INIS)

    Bryer, Pamela J.; Scoggins, Mateo; McClintock, Nancy L.

    2010-01-01

    Non-point-source pollution is a major source of ecological impairment in urban stream systems. Recent work suggests that coal-tar pavement sealants, used extensively to protect parking areas, may be contributing a large portion of the polycyclic aromatic hydrocarbon (PAH) loading seen in urban stream sediments. The hypothesis that dried coal-tar pavement sealant flake could alter the macroinvertebrate communities native to streams in Austin, TX was tested using a controlled outdoor laboratory type approach. The treatment groups were: control, low, medium, and high with total PAH concentrations (TPAH = sum of 16 EPA priority pollutant PAHs) of 0.1, 7.5, 18.4, and 300 mg/kg respectively. The low, medium, and high treatments were created via the addition of dried coal-tar pavement sealant to a sterile soil. At the start of the 24-day exposure, sediment from a minimally impacted local reference site containing a community of live sediment-dwelling benthic macroinvertebrates was added to each replicate. An exposure-dependent response was found for several stream health measures and for several individual taxa. There were community differences in abundance (P = 0.0004) and richness (P < 0.0001) between treatments in addition to specific taxa responses, displaying a clear negative relationship with the amount of coal-tar sealant flake. These results support the hypothesis that coal-tar pavement sealants contain bioavailable PAHs that may harm aquatic environments. - Coal-tar pavement sealants degrade stream invertebrate communities.

  8. Coal-tar based pavement sealant toxicity to freshwater macroinvertebrates.

    Science.gov (United States)

    Bryer, Pamela J; Scoggins, Mateo; McClintock, Nancy L

    2010-05-01

    Non-point-source pollution is a major source of ecological impairment in urban stream systems. Recent work suggests that coal-tar pavement sealants, used extensively to protect parking areas, may be contributing a large portion of the polycyclic aromatic hydrocarbon (PAH) loading seen in urban stream sediments. The hypothesis that dried coal-tar pavement sealant flake could alter the macroinvertebrate communities native to streams in Austin, TX was tested using a controlled outdoor laboratory type approach. The treatment groups were: control, low, medium, and high with total PAH concentrations (TPAH = sum of 16 EPA priority pollutant PAHs) of 0.1, 7.5, 18.4, & 300 mg/kg respectively. The low, medium, and high treatments were created via the addition of dried coal-tar pavement sealant to a sterile soil. At the start of the 24-day exposure, sediment from a minimally impacted local reference site containing a community of live sediment-dwelling benthic macroinvertebrates was added to each replicate. An exposure-dependent response was found for several stream health measures and for several individual taxa. There were community differences in abundance (P = 0.0004) and richness (P pavement sealants contain bioavailable PAHs that may harm aquatic environments. Copyright 2009 Elsevier Ltd. All rights reserved.

  9. Coal-tar based pavement sealant toxicity to freshwater macroinvertebrates

    Energy Technology Data Exchange (ETDEWEB)

    Bryer, P.J.; Scoggins, M.; McClintock, N.L. [Lamar University, Beaumont, TX (United States). Dept. of Biology

    2010-05-15

    Non-point-source pollution is a major source of ecological impairment in urban stream systems. Recent work suggests that coal-tar pavement sealants, used extensively to protect parking areas, may be contributing a large portion of the polycyclic aromatic hydrocarbon (PAH) loading seen in urban stream sediments. The hypothesis that dried coal-tar pavement sealant flake could alter the macroinvertebrate communities native to streams in Austin, TX was tested using a controlled outdoor laboratory type approach. The treatment groups were: control, low, medium, and high with total PAH concentrations (TPAH = sum of 16 EPA priority pollutant PAHs) of 0.1, 7.5, 18.4, & 300 mg/kg respectively. The low, medium, and high treatments were created via the addition of dried coal-tar pavement sealant to a sterile soil. At the start of the 24-day exposure, sediment from a minimally impacted local reference site containing a community of live sediment-dwelling benthic macroinvertebrates was added to each replicate. An exposure-dependent response was found for several stream health measures and for several individual taxa. There were community differences in abundance (P = 0.0004) and richness (P < 0.0001) between treatments in addition to specific taxa responses, displaying a clear negative relationship with the amount of coal-tar sealant flake. These results support the hypothesis that coal-tar pavement sealants contain bioavailable PAHs that may harm aquatic environments.

  10. Aquatic macroinvertebrates and water quality of Sandia Canyon, Los Alamos National Laboratory, November 1993--October 1994

    Energy Technology Data Exchange (ETDEWEB)

    Cross, S.

    1995-08-01

    The Ecological Studies Team (EST) of ESH-20 at Los Alamos National Laboratory (LANL) has collected samples from the stream within Sandia Canyon since the summer of 1990. These field studies gather water quality measurements and collect aquatic macroinvertebrates from permanent sampling sites. Reports by Bennett (1994) and Cross (1994) discuss previous EST aquatic studies in Sandia Canyon. This report updates and expands those findings. EST collected water quality data and aquatic macroinvertebrates at five permanent stations within the canyon from November 1993 through October 1994. The two upstream stations are located below outfalls that discharge industrial and sanitary waste effluent into the stream, thereby maintaining year-round flow. Some water quality parameters are different at the first three stations from those expected of natural streams in the area, indicating degraded water quality due to effluent discharges. The aquatic habitat at the upper stations has also been degraded by sedimentation and channelization. The macroinvertebrate communities at these stations are characterized by low diversities and unstable communities. In contrast, the two downstream stations appear to be in a zone of recovery, where water quality parameters more closely resemble those found in natural streams of the area. The two lower stations have increased macroinvertebrate diversity and stable communities, further indications of downstream water quality improvement.

  11. Risk assessment of imidacloprid use in forest settings on the aquatic macroinvertebrate community.

    Science.gov (United States)

    Benton, Elizabeth P; Grant, Jerome F; Nichols, Rebecca J; Webster, R Jesse; Schwartz, John S; Bailey, Joseph K

    2017-11-01

    The isolated effects of a single insecticide can be difficult to assess in natural settings because of the presence of numerous pollutants in many watersheds. Imidacloprid use for suppressing hemlock woolly adelgid, Adelges tsugae (Annand) (Hemiptera: Adelgidae), in forests offers a rare opportunity to assess potential impacts on aquatic macroinvertebrates in relatively pristine landscapes. Aquatic macroinvertebrate communities were assessed in 9 streams in Great Smoky Mountains National Park (southern Appalachian Mountains, USA). The streams flow through hemlock conservation areas where imidacloprid soil drench treatments were applied for hemlock woolly adelgid suppression. Sites were located upstream and downstream of the imidacloprid treatments. Baseline species presence data (pre-imidacloprid treatment) were available from previous sample collections at downstream sites. Downstream and upstream sites did not vary in numerous community measures. Although comparisons of paired upstream and downstream sites showed differences in diversity in 7 streams, higher diversity was found more often in downstream sites. Macroinvertebrate functional feeding groups and life habits were similar between downstream and upstream sites. Downstream and baseline stream samples were similar. While some functional feeding group and life habit species richness categories varied, variations did not indicate poorer quality downstream communities. Imidacloprid treatments applied according to US Environmental Protection Agency federal restrictions did not result in negative effects to aquatic macroinvertebrate communities, which indicates that risks of imidacloprid use in forest settings are low. Environ Toxicol Chem 2017;36:3108-3119. © 2017 SETAC. © 2017 SETAC.

  12. The taphonomy of a remarkable leaf bed assemblage from the Late Oligocene-Early Miocene Gore Lignite Measures, southern New Zealand

    Energy Technology Data Exchange (ETDEWEB)

    Ferguson, David K.; Zetter, Reinhard; Vavra, Norbert [Department of Paleontology, University of Vienna, Althanstrasse 14, A-1090 Vienna (Austria); Lee, Daphne E. [Department of Geology, University of Otago, PO Box 56, Dunedin (New Zealand); Bannister, Jennifer M. [Department of Botany, University of Otago, PO Box 56, Dunedin (New Zealand); Jordan, Gregory J. [School of Plant Sciences, University of Tasmania, Private Bag 55, Hobart, Tasmania 7001 (Australia); Mildenhall, Dallas C. [GNS Science, PO Box 30-368, Lower Hutt (New Zealand)

    2010-08-01

    A diverse assemblage of fossil leaves showing cellular detail is reported from the Late Oligocene-Early Miocene Gore Lignite Measures, southern New Zealand. The leaf-remains include at least five conifers, such as the genera Agathis, Dacrycarpus, Phyllocladus and Dacrydium, as well as a number of angiosperms including Gymnostoma, Nothofagus Subgenus Brassospora, Phormium, Proteaceae, Sapindaceae and Ericaceae. A parallel palynological study has identified a number of the same elements. The leaf layers represent litter horizons laid down in pools on the surface of a subtropical ombrotrophic forest mire that formed on an extensive low-lying coastal plain. Highly acidic water ponded in tree-fall depressions prevented microbial decay of the foliage. Taxa represented by both leaves and pollen are considered to have been components of the autochthonous swamp forest. Some other pollen grains are thought to represent local elements, based on the pollination biology of their nearest living relatives. Other taxa whose extant representatives are wind-pollinated may have grown further away. (author)

  13. Altitudinal distribution limits of aquatic macroinvertebrates

    DEFF Research Database (Denmark)

    Madsen, Philip B.; Morabowen, Andrés; Andino, Patricio

    2015-01-01

    1. Temperature and oxygen are recognised as the main drivers of altitudinal limits of species distributions. However, the two factors are linked, and both decrease with altitude, why their effects are difficult to disentangle. 2. This was experimentally addressed using aquatic macroinvertebrates...... relatively small differences in temperature and oxygen may produce effects explaining ecological patterns, and depending on the taxon, either water temperature or oxygen saturation, without clear interacting effects, are important drivers of altitudinal limits....

  14. Sediment Burial Intolerance of Marine Macroinvertebrates.

    Directory of Open Access Journals (Sweden)

    Vicki J Hendrick

    Full Text Available The marine environment contains suspended particulate matter which originates from natural and anthropogenic sources. Settlement of this material can leave benthic organisms susceptible to smothering, especially if burial is sudden i.e. following storms or activities such as dredging. Their survival will depend on their tolerance to, and their ability to escape from burial. Here we present data from a multi-factorial experiment measuring burial responses incorporating duration, sediment fraction and depth. Six macroinvertebrates commonly found in sediment rich environments were selected for their commercial and/or conservation importance. Assessments revealed that the brittle star (Ophiura ophiura, the queen scallop (Aequipecten opercularis and the sea squirt (Ciona intestinalis were all highly intolerant to burial whilst the green urchin (Psammichinus miliaris and the anemone (Sagartiogeton laceratus, showed intermediate and low intolerance respectively, to burial. The least intolerant, with very high survival was the Ross worm (Sabellaria spinulosa. With the exception of C. intestinalis, increasing duration and depth of burial with finer sediment fractions resulted in increased mortality for all species assessed. For C. intestinalis depth of burial and sediment fraction were found to be inconsequential since there was complete mortality of all specimens buried for more than one day. When burial emergence was assessed O. ophiura emerged most frequently, followed by P. miliaris. The former emerged most frequently from the medium and fine sediments whereas P. miliaris emerged more frequently from coarse sediment. Both A. opercularis and S. laceratus showed similar emergence responses over time, with A. opercularis emerging more frequently under coarse sediments. The frequency of emergence of S. laceratus increased with progressively finer sediment and C. intestinalis did not emerge from burial irrespective of sediment fraction or depth. Finally

  15. Spatial and temporal effects of olive mill wastewaters to stream macroinvertebrates and aquatic ecosystems status.

    Science.gov (United States)

    Karaouzas, Ioannis; Skoulikidis, Nikolaos T; Giannakou, Urania; Albanis, Triantafyllos A

    2011-12-01

    Olive mill wastewater (OMW) is one of the major and most challenging organic pollutants in olive oil production countries. However, the knowledge about the in-situ effects of olive mill wastewaters to lotic ecosystems and their benthic organisms is very limited. To resolve this, eight sampling sites were selected upstream and downstream the outflow of several olive mills to assess the spatial and temporal effects of OMW to stream macroinvertebrates and to ecological status of stream ecosystems. Biotic (macroinvertebrates) and abiotic (physicochemical, hydromorphological) data were monitored for two years thus following the biennial cycle of olive growth and production and hydrological variation (drought-wet years). The results of this study revealed the spatial and temporal structural deterioration of the aquatic community due to OMW pollution with consequent reduction of the river capacity for reducing the effects of polluting substances through internal mechanisms of self-purification. OMW, even highly diluted, had dramatic impacts on the aquatic fauna and to the ecological status of the receiving stream ecosystems. The organic load of the wastewater expressed as BOD(5), COD and TSS, substrate contamination (sewage bacteria) and distance from the mill outlet, were the most important factors affecting macroinvertebrate assemblages while the typology (i.e. slope, altitude) and hydrology of the stream site (i.e. mountainous-lowland) and the intensity and volume of the wastewater were the most important determinants of self-purification processes. As OMW are usually being discharged in small size streams that are not considered in the Water Framework Directive 2000/60/EC, there is a need for including such systems into monitoring and assessment schemes as they may significantly contribute to the pollution load of the river basin. Furthermore, guidelines to manage these wastes through technologies that minimise their environmental impact and lead to a sustainable use

  16. Invasive alien species water hyacinth Eichhornia crassipes as abode for macroinvertebrates in hypertrophic Ramsar Site, Lake Xochimilco, Mexico.

    Science.gov (United States)

    Rocha-Ramirez, A; Robles-Valderrama, E; Ramirez-Flores, E

    2014-11-01

    This paper presents information on the density, diversity and functional feeding groups of macroinvertebrate assemblages associated with water hyacinth in Antiguo Canal Cuemanco, part of Lake Xochimilco in Mexico City. Rare (low frequency and density) and dominant (high frequency and density) taxa prevailed in the assemblages, with the most predominant being Hyalella azteca, Chironomus plumosus and Ischnura denticollis. Nonmetric Multidimensional Scaling confirmed two climatic seasons: warm-rainy and cold-dry; the former with the highest diversity and density of taxa. Canonical Correspondence Analysis showed that conductivity, nitrates and turbidity explained the density variations of taxa. Antiguo Canal Cuemanco waters are spatially homogeneous with the characteristics of hypertrophic shallow lakes, inhabited by scrapers and gathering-collectors. The species found were tolerant to organic pollution.

  17. Affects and assemblages

    DEFF Research Database (Denmark)

    Samson, Kristine

    the paper raises the questions where to locate aesthetics when planners and architects wishes to design for aesthetical experiences and sensations rather than formal objects. The paper will proceed through a brief outline of the recent notion of assemblage and affect in urban studies, planning theory...... happens to aesthetics and how does it change the existing social and geographical understanding of urban space? The paper sets out to reintroduce aesthetical aspects of affects and assemblages in relation to urban space and urban planning. It presupposes urban space as a continuous state of becoming where...

  18. Assessing the Effects of Hydromorphological Degradation on Macroinvertebrate Indicators in Rivers: Examples, Constraints and Outlook

    DEFF Research Database (Denmark)

    Friberg, N.; Sandin, L.; Pedersen, Morten Lauge

    2009-01-01

    data of 28 Swedish streams, whereas moderate (R2 0.43) relationships with more detailed measurements of morphology were found in 2 Danish studies (39 and 6 streams, respectively). Although evidence exists in the literature on the importance of physical features for in-stream biota in general......) scaling issues (spatial and temporal) when relating habitat surveys to macroinvertebrate assessments, and 3) the scope of commonly used macroinvertebrate assessment systems (mainly focusing on water chemistry perturbation, such as eutrophication and acidification). The need is urgent to develop refined......An extensive amount of literature on linkages between the in-stream physical environment and river benthic macroinvertebrates reports a number of relationships across multiple spatial scales. We analyzed data on different spatial scales to elucidate the linkages between different measurements...

  19. Functional diversity measures revealed impacts of non-native species and habitat degradation on species-poor freshwater fish assemblages.

    Science.gov (United States)

    Colin, Nicole; Villéger, Sébastien; Wilkes, Martin; de Sostoa, Adolfo; Maceda-Veiga, Alberto

    2018-06-01

    Trait-based ecology has been developed for decades to infer ecosystem responses to stressors based on the functional structure of communities, yet its value in species-poor systems is largely unknown. Here, we used an extensive dataset in a Spanish region highly prone to non-native fish invasions (15 catchments, N=389 sites) to assess for the first time how species-poor communities respond to large-scale environmental gradients using a taxonomic and functional trait-based approach in riverine fish. We examined total species richness and three functional trait-based indices available when many sites have ≤3 species (specialization, FSpe; originality, FOri and entropy, FEnt). We assessed the responses of these taxonomic and functional indices along gradients of altitude, water pollution, physical habitat degradation and non-native fish biomass. Whilst species richness was relatively sensitive to spatial effects, functional diversity indices were responsive across natural and anthropogenic gradients. All four diversity measures declined with altitude but this decline was modulated by physical habitat degradation (richness, FSpe and FEnt) and the non-native:total fish biomass ratio (FSpe and FOri) in ways that varied between indices. Furthermore, FSpe and FOri were significantly correlated with Total Nitrogen. Non-native fish were a major component of the taxonomic and functional structure of fish communities, raising concerns about potential misdiagnosis between invaded and environmentally-degraded river reaches. Such misdiagnosis was evident in a regional fish index widely used in official monitoring programs. We recommend the application of FSpe and FOri to extensive datasets from monitoring programs in order to generate valuable cross-system information about the impacts of non-native species and habitat degradation, even in species-poor systems. Scoring non-native species apart from habitat degradation in the indices used to determine ecosystem health is

  20. Aquatic macroinvertebrates associated with roots of Eichhornia azuera (Swarts Kunth (Pontederiaceae in an oxbow lake in Pantanal, MS

    Directory of Open Access Journals (Sweden)

    Hugo Henrique L. Saulino

    2014-09-01

    Full Text Available Macrophytes play an important role in the community structure of aquatic systems. In this study, we examined the macroinvertebrate communities within 20 Eichhornia azurea roots in an oxbow lake in Pantanal (MS during dry season. Species abundance and richness were compared via linear regression, and the mean relative proportion of macroinvertebrates among root samples was determined. Macroinvertebrates were identified to the lowest practical taxonomic level, and root volume was measured using the volume displacement method. We identified 371 specimens, belonging to 31 families and 21 taxonomic groups. Chironomus sp. (Chironomidae, Slavinia sp. and Dero sp. (Naididae, all detritivores, were most the represented taxon. Regression analysis indicated a positive correlation between root volume and the abundance and richness of the macroinvertebrate community. Analysis of variance showed no statistically significant differences between species abundance and richness among different E. azuera root volumes, however we did observe a trend toward a positive correlation of both variables with increasing root volume. We suspect that greater root volumes should increase microhabitat availability, which could explain this observed trend. Our results indicate that E. azurea roots may play an important ecologic role (e.g., by providing shelter, food stock in lake macroinvertebrate communities.

  1. Temporally variable macroinvertebrate-stone relationships in streams

    DEFF Research Database (Denmark)

    Jacobsen, D.

    2005-01-01

    of fauna parameter and stone variable from different sampling dates (n=9-11) were rarely correlated to any of the measures of stream stability, this study has demonstrated high temporal variability in fauna-stone relationships (CV's of regression slopes). Consequently, temporally un-replicated studies......Stones were used to sample macroinvertebrates and characterise microhabitats at monthly or bimonthly intervals in six Ecuadorian streams covering a gradient in four different stability measures and other stream characteristics. The physical variables current velocity, water depth, horizontal...... of families vs. individuals) were related to the physical characteristics of individual stone habitats. My second objective was to quantify temporal variability in fauna-stone relationships and to analyse if such variability was related to overall stability of stream reaches. Partial Least Squares (PLS...

  2. Macroinvertebrate community assembly in pools created during peatland restoration.

    Science.gov (United States)

    Brown, Lee E; Ramchunder, Sorain J; Beadle, Jeannie M; Holden, Joseph

    2016-11-01

    Many degraded ecosystems are subject to restoration attempts, providing new opportunities to unravel the processes of ecological community assembly. Restoration of previously drained northern peatlands, primarily to promote peat and carbon accumulation, has created hundreds of thousands of new open water pools. We assessed the potential benefits of this wetland restoration for aquatic biodiversity, and how communities reassemble, by comparing pool ecosystems in regions of the UK Pennines on intact (never drained) versus restored (blocked drainage-ditches) peatland. We also evaluated the conceptual idea that comparing reference ecosystems in terms of their compositional similarity to null assemblages (and thus the relative importance of stochastic versus deterministic assembly) can guide evaluations of restoration success better than analyses of community composition or diversity. Community composition data highlighted some differences in the macroinvertebrate composition of restored pools compared to undisturbed peatland pools, which could be used to suggest that alternative end-points to restoration were influenced by stochastic processes. However, widely used diversity metrics indicated no differences between undisturbed and restored pools. Novel evaluations of restoration using null models confirmed the similarity of deterministic assembly processes from the national species pool across all pools. Stochastic elements were important drivers of between-pool differences at the regional-scale but the scale of these effects was also similar across most of the pools studied. The amalgamation of assembly theory into ecosystem restoration monitoring allows us to conclude with more certainty that restoration has been successful from an ecological perspective in these systems. Evaluation of these UK findings compared to those from peatlands across Europe and North America further suggests that restoring peatland pools delivers significant benefits for aquatic fauna by

  3. A Rapid Assessment of Macroinvertebrates Associated with Salvinia ...

    African Journals Online (AJOL)

    Salvinia molesta is an invasive species in the Okavango Delta. The plant forms monotypic covers in places where it occurs and thus affects macroinvertebrates diversity within them. Three habitats with low, moderate and heavy infestation by the weed were selected inside Moremi Game Reserve to study macroinvertebrates ...

  4. Effect of sewage oxidation pond effluent on macroinvertebrate ...

    African Journals Online (AJOL)

    The influence on aquatic macroinvertebrates of sewage oxidation pond effluent discharge was investigated in a tropical forest stream in Ile-Ife, Nigeria. A total of 858 individual macroinvertebrates were collected. They belong to 8 taxa which represent 5 orders. The number of taxa was low when compared to the findings in ...

  5. Turnover patterns in fish versus macroinvertebrates — implications ...

    African Journals Online (AJOL)

    Spatial patterns in taxonomic richness and turnover for fish and aquatic macroinvertebrates are compared to assess the relative usefulness of each taxonomic group in mapping biodiversity patterns. Fish and aquatic macroinvertebrate species data for sites down the longitudinal axes of nine rivers in four provinces along the ...

  6. Assemblages of Patient Safety

    DEFF Research Database (Denmark)

    Balatsas Lekkas, Angelos

    2016-01-01

    This thesis identifies how design processes emerge during the use of devices in healthcare, by attending to assemblages where contingencies of risk and harm co-exist with the contribution of healthcare professionals to the safe care of patients. With support from the field of Science and Technology...... practices of interdisciplinary care....

  7. Translanguaging and Semiotic Assemblages

    Science.gov (United States)

    Pennycook, Alastair

    2017-01-01

    This paper asks what translanguaging could start to look like if it incorporated an expanded version of language and questioned not only to the borders between languages but also the borders between semiotic modes. Developing the idea of spatial repertoires and assemblages, and looking at data from a Bangladeshi-owned corner shop, this paper…

  8. Assessment of Ecological Quality of the Tajan River in Iran Using a Multimetric Macroinvertebrate Index and Species Traits

    Science.gov (United States)

    Aazami, Jaber; Esmaili Sari, Abbas; Abdoli, Asghar; Sohrabi, Hormoz; Van den Brink, Paul J.

    2015-07-01

    The objectives of this study were to assess the biological water of the Iranian Tajan River using different metrics, i.e., a Multimetric Macroinvertebrate Index (MMI) and a traits-based method. Twenty-eight physico-chemical parameters, 10 habitat factors, and abundance of macroinvertebrates were obtained for 17 sites. The Shahid-Rajaie dam divides the Tajan River into an up- and downstream part, with different land uses. Eighteen metrics were used to represent four components of ecosystem quality, including tolerance (Hilsenhoff, SIGNAL), diversity (Margalef, Shannon-Wiener, Simpson, and Evenness), abundance (total number of taxa, individuals, Ephemeroptera, Plecoptera, Trichoptera, EPT, and Insects), and composition of assemblages (% Ephemeroptera, % Plecoptera, % Trichoptera, and % EPT Taxa). The integrated MMI was calculated by averaging the obtained scores of all indices. In the next step, we gathered information on 22 biological traits of macroinvertebrates to evaluate whether (group of) traits could be identified that are indicative for specific or general stress. Result showed a decrease in MMI from upstream (very good water quality) to downstream (bad) due to human activities. Industrial activities like pulping and papermaking operations or sand mining in the downstream part had more effects than agriculture and fish ponds in the upstream part. A redundancy analysis biplot showed the variation between the modalities of trait of macroinvertebrates and their correlation with physico-chemical parameters in Tajan River. The findings show that traits can be indicative for different kind of stress but that more effort has to be put in gathering data sets to disentangle the effect of habitat quality, pollution, and the physico-chemical properties of high- versus lowland rivers.

  9. Benthic macroinvertebrates in Italian rice fields

    Directory of Open Access Journals (Sweden)

    Daniela Lupi

    2013-02-01

    Full Text Available Rice fields can be considered man-managed temporary wetlands. Five rice fields handled with different management strategies, their adjacent channels, and a spring were analysed by their benthic macroinvertebrate community to i evaluate the role of rice agroe- cosystem in biodiversity conservation; ii find indicator species which can be used to compare the ecological status of natural wetlands with rice agroecosystems; and iii find the influence of environmental variables on biodiversity. Different methods of data analysis with increasing degree of complexity – from diversity index up to sophisticated multivariate analysis – were used. The investigation provided a picture of benthic macroinvertebrates inhabiting rice agroecosystems where 173 taxa were identified, 89 of which detected in rice paddies. Among them, 4 phyla (Mollusca, Annelida, Nematomorpha, and Arthropoda, 8 classes (Bivalvia, Gastropoda, Oligochaeta, Hirudinea, Gordioida, Insecta, Branchiopoda, and Malacostraca, 24 orders, 68 families, 127 genera and 159 species have been found. Ten threatened and 3 invasive species were detected in the habitats examined. The information obtained by the different methods of data analysis allowed a more comprehensive view on the value of the components of rice agroecosystems. Data analyses highlighted significant differences between habitats (feeding channel and rice field, with higher diversity observed in channels, and emphasised the role of the water chemical-physical parameters. The period of water permanence in rice fields resulted to be only one of the factors influencing the community of benthic macroinvertebrates. The presence of rare/endangered species allowed characterising some stations, but it was less informative about management strategies in rice paddies because most of these species were absent in rice fields.

  10. Aquatic macroinvertebrates of the Jablanica river, Serbia

    Directory of Open Access Journals (Sweden)

    Stefanović Katarina S.

    2009-01-01

    Full Text Available Research on the community of aquatic macroinvertebrates was carried out during 2005 and 2006 at four sampling sites along the Jablanica River, a right-hand tributary of the Kolubara River. Fifty-seven taxa were recorded in the course of the investigation. The most diverse group was Ephemeroptera, followed by Trichoptera and Plecoptera. Members of the Rhitrogena semicolorata group were the most abundant. Our results could be the basis for evaluation of the influence of damming of the Jablanica River on the status of its water and can serve as a model for studying the influ­ence of hydromorphological degradation of aquatic ecosystems.

  11. Demersal and larval fish assemblages in the Chukchi Sea

    Science.gov (United States)

    Norcross, Brenda L.; Holladay, Brenda A.; Busby, Morgan S.; Mier, Kathryn L.

    2010-01-01

    A multidisciplinary research cruise was conducted in the Chukchi Sea in summer 2004 during which we investigated assemblages of small demersal fishes and ichthyoplankton and the water masses associated with these assemblages. This study establishes a baseline of 30 demersal fish and 25 ichthyoplankton taxa in US and Russian waters of the Chukchi Sea. Presence/absence of small demersal fish clustered into four assemblages: Coastal Fishes, Western Chukchi Fishes, South Central Chukchi Fishes, and North Central Chukchi Fishes. Habitats occupied by small demersal fishes were characterized by sediment type, bottom salinity, and bottom temperature. Abundance of ichthyoplankton grouped into three assemblages with geographical extent similar to that of the bottom assemblages, except that there was a single assemblage for Central Chukchi Fishes. Water-column temperature and salinity characterized ichthyoplankton habitats. Three water masses, Alaska Coastal Water, Bering Sea Water, and Winter Water, were identified from both bottom and depth-averaged water-column temperature and salinity. A fourth water mass, Resident Chukchi Water, was identified only in the bottom water. The water mass and habitat characteristics with which demersal and larval fish assemblages were associated create a baseline to measure anticipated effects of climate change that are expected to be most severe at high latitudes. Monitoring fish assemblages could be a tool for assessing the effects of climate change. Climate-induced changes in distributions of species would result in a restructuring of fish assemblages in the Chukchi Sea.

  12. Variance in water chemistry parameters in isolated wetlands of Florida, USA, and relationships with macroinvertebrate and diatom community structure

    Science.gov (United States)

    Eighty small isolated wetlands throughout Florida were sampled in 2005 to explore within-site variability of water chemistry parameters and relate water chemistry to macroinvertebrate and diatom community structure. Three samples or measures of water were collected within each si...

  13. Macroinvertebrate diversity in the karst Jadro River (Croatia

    Directory of Open Access Journals (Sweden)

    Rađa Biljana

    2008-01-01

    Full Text Available This paper presents the results of 10 years of investigation of the aquatic macroinvertebrate fauna along the karst Jadro River. The Jadro is a typical karst river. Benthic macroinvertebrates were collected along the river at 15 sites by standard methods of sampling, in addition to which several physicochemical parameters were also determined. Based on qualitative and quantitative composition of the macroinvertebrate fauna, correspondence analysis divided the river course into three sections: upstream, midcourse, and downstream. Forty-three taxa were recorded. Results of saprobiological analysis based on macrozoobenthos indicate that water of the Jadro River belongs to quality classes I and II.

  14. Downstream effects of hydropower production on aquatic macroinvertebrate assemblages in two rivers in Costa Rica

    Directory of Open Access Journals (Sweden)

    Ramsa Chaves-Ulloa

    2014-04-01

    Full Text Available Existe poca información publicada sobre el efecto de grandes represas hidroeléctricas (>15m alto en ríos tropicales. Investigamos los efectos de estas represas en las comunidades de macroinvertebrados acuáticos en dos ríos de Costa Rica. Medimos características físico-químicas y recolectamos macroinvertebrados a lo largo del año en dos ríos represados, Peñas Blancas y San Lorenzo, así como en el río Chachagua, el cual no era utilizado para la producción hidroeléctrica. Los sitios arriba y debajo de las represas presentaron diferencias físico-químicas, con amplia variación y valores extremos en las variables medidas debajo de la represa en el Río San Lorenzo. Los sitios arriba de las represas estaban dominados por colectores-recolectores-raspadores y nadadores-colgadores, mientras que debajo de las represas hubo una representación más equitativa de grupos funcionales. En contraste, las comunidades fueron semejantes en dos sitios a diferente elevación en el río sin represa. La presencia de afluentes podría haber facilitado la recuperación de macroinvertebrados arriba de la casa de máquinas, pero las comunidades fueron similares bajo la casa y abajo de la represa. Una liberación masiva de sedimentos disminuyó la abundancia y el número de táxones bajo la represa en el Río Peñas Blancas.

  15. Spatial variability in macroinvertebrate assemblages along and among neighbouring equatorial glacier-fed streams

    DEFF Research Database (Denmark)

    Kuhn, J.; Andino, P.; Calvez, R.

    2011-01-01

    , the three sites were placed at comparable distances from the glacier and were grouped as ‘upper’ (50–200 m), ‘middle’ (1.5 km) and ‘lower’ sites (3.5–5.6 km). 3. In total, 2200 individuals (64% chironomids) were collected and 47 taxa (30 dipterans, 18 of these Chironomidae) identified. Density ranged from...

  16. Temporal variability in discharge and benthic macroinvertebrate assemblages in a tropical glacier-fed stream

    DEFF Research Database (Denmark)

    Jacobsen, Dean; Andino, Patricio; Calvez, Roger

    2014-01-01

    discharge parameters 3, 6, 9, 21, and 45 d before sampling. The effect of flow (slopes of regressions of faunal metrics vs flow) did not differ among sites, but the amount of variation explained by flow was significant only at the 2 downstream sites. Little synchrony was found in variability among sites......-fed stream, a prerequisite for subsequent predictions of consequences of tropical glacier melting on diversity, composition, and stability of stream communities....

  17. Long-term variations in benthic macroinvertebrate assemblages off Bombay, India

    Digital Repository Service at National Institute of Oceanography (India)

    Parulekar, A.H.; Ansari, Z.A.; Harkantra, S.N.; Rodrigues, C.L.

    Changes in composition, number, and biomass of macrobenthic infauna in relation to environmental deterioration in the coastal zone of Bombay, India were followed between 1974 and 1983. A time-dependent impoverishment in population density and faunal...

  18. La Popala creek: quality analysis of water from some physical - chemical, microbiological variables and aquatic macroinvertebrates

    International Nuclear Information System (INIS)

    Milan Valoyes, Wandy Yohanna; Caicedo Quintero, Orlando; Aguirre Ramirez, Nestor Jaime

    2011-01-01

    The Popala creek supplies water to the people of Bolombolo in Venecia municipality in Antioquia, Colombia. In November 14th and 28th of 2009, four sampling station were located along the creek, to measure five sets of variables: physico- chemical, microbiological, aquatic macroinvertebrate, biological indicators and biotic index BMWP.Physico- chemical variables, aquatic macroinvertebrates and index BMWP indicate good environmental conditions in station 2, located about 150 m from the headwaters (station 1). On the other hand, Station 4, located near to the Cauca River, exhibits deterioration in water quality. Stations 3 and 4 displayed high levels of fecal coliforms. However, the samples taken from Bolombolo's water supply network indicate the water of the aqueduct is adequate for human consumption.

  19. Evaluation of Macroinvertebrate Data Based on Autoecological Information

    Directory of Open Access Journals (Sweden)

    Juhász I.

    2016-12-01

    Full Text Available Various data (biological, chemical, hydrological and morphological have been gathered within the frame of the monitoring of the Water Framework Directive from 2007 in Hungary. This data only used a status assessment of certain water bodies in Hungary. The macroinvertebrates indicate many environmental factors well; therefore, they are very useful in detecting changes in the status of an environment. The main aim in this research was to investigate changes in environmental variables and decide how these variables cause big changes in the macroinvertebrate fauna. The macroinvertebrate data was processed using the ASTERICS 4.0.4 program. The program calculated some important metrics (i.e., microhabitat distributions, longitudinal zonation, functional feeding guilds, etc.. These metrics were compared with the chemical and hydrological data. The main conclusion is that if we have enough of a frequency and quality of macroinvertebrate data, we can understand changes in the environment of an ecosystem.

  20. Effects of dredged sediment disposal on the coastal marine macrobenthic assemblage in Southern Brazil

    Directory of Open Access Journals (Sweden)

    L. G. Angonesi

    Full Text Available The aim of this study was to evaluate the deposition impact of dredged material from Patos lagoon estuary on a benthic macroinvertebrate assemblage structure in an adjacent coastal marine area. Nine sampling stations were chosen at random in the disposal area, and nine others in the same way in an adjacent control area. Samples were collected at a 19 m depth before sediment disposal (11 July 2000, during dredging and disposal operations (25 Oct. 2000, and three months thereafter (24 Aug. 2001. Statistical analysis indicated that sampling periods presented similar characteristics in both the control and disposal sites. Disposal of dredged sediment from Patos lagoon had no detectable detrimental effects upon macrobenthic faunal assemblage at the dumping site. This result is attributed both to adaptation of resident biota to dynamic sedimentary conditions and to the fine estuarine sediment dredged, the dispersion of which in the water column might have minimized sediment deposition and consequent damage to the benthic fauna.

  1. The macroinvertebrates of Magela Creek, Northern Territory

    International Nuclear Information System (INIS)

    Marchant, R.

    1982-04-01

    The littoral zones of five permanent billabongs in Magela Creek were sampled monthly for macroinvertebrates. Greatest numbers of taxa and individuals were caught in the late wet season and early dry season in the shallow billabongs; in the deep billabongs, seasonal variations were not so marked. These changes appeared to be associated with the development of macrophytes, which offered food and shelter to the invertebrate fauna. The dominant groups were the Chironomidae, Oligochaetae and Ephemeroptera. The seasonal patterns of the catches were sufficiently consistent for future samples to be able to be compared with these initial ones with some confidence that any changes are real. This work is part of a larger study into the biota and water quality of Magela Creek designed to provide data on aquatic communities before mining of the Ranger uranium deposit starts

  2. Macroinvertebrate community assembly in pools created during peatland restoration

    International Nuclear Information System (INIS)

    Brown, Lee E.; Ramchunder, Sorain J.; Beadle, Jeannie M.; Holden, Joseph

    2016-01-01

    Many degraded ecosystems are subject to restoration attempts, providing new opportunities to unravel the processes of ecological community assembly. Restoration of previously drained northern peatlands, primarily to promote peat and carbon accumulation, has created hundreds of thousands of new open water pools. We assessed the potential benefits of this wetland restoration for aquatic biodiversity, and how communities reassemble, by comparing pool ecosystems in regions of the UK Pennines on intact (never drained) versus restored (blocked drainage-ditches) peatland. We also evaluated the conceptual idea that comparing reference ecosystems in terms of their compositional similarity to null assemblages (and thus the relative importance of stochastic versus deterministic assembly) can guide evaluations of restoration success better than analyses of community composition or diversity. Community composition data highlighted some differences in the macroinvertebrate composition of restored pools compared to undisturbed peatland pools, which could be used to suggest that alternative end-points to restoration were influenced by stochastic processes. However, widely used diversity metrics indicated no differences between undisturbed and restored pools. Novel evaluations of restoration using null models confirmed the similarity of deterministic assembly processes from the national species pool across all pools. Stochastic elements were important drivers of between-pool differences at the regional-scale but the scale of these effects was also similar across most of the pools studied. The amalgamation of assembly theory into ecosystem restoration monitoring allows us to conclude with more certainty that restoration has been successful from an ecological perspective in these systems. Evaluation of these UK findings compared to those from peatlands across Europe and North America further suggests that restoring peatland pools delivers significant benefits for aquatic fauna by

  3. Macroinvertebrate community assembly in pools created during peatland restoration

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Lee E., E-mail: l.brown@leeds.ac.uk; Ramchunder, Sorain J.; Beadle, Jeannie M.; Holden, Joseph

    2016-11-01

    Many degraded ecosystems are subject to restoration attempts, providing new opportunities to unravel the processes of ecological community assembly. Restoration of previously drained northern peatlands, primarily to promote peat and carbon accumulation, has created hundreds of thousands of new open water pools. We assessed the potential benefits of this wetland restoration for aquatic biodiversity, and how communities reassemble, by comparing pool ecosystems in regions of the UK Pennines on intact (never drained) versus restored (blocked drainage-ditches) peatland. We also evaluated the conceptual idea that comparing reference ecosystems in terms of their compositional similarity to null assemblages (and thus the relative importance of stochastic versus deterministic assembly) can guide evaluations of restoration success better than analyses of community composition or diversity. Community composition data highlighted some differences in the macroinvertebrate composition of restored pools compared to undisturbed peatland pools, which could be used to suggest that alternative end-points to restoration were influenced by stochastic processes. However, widely used diversity metrics indicated no differences between undisturbed and restored pools. Novel evaluations of restoration using null models confirmed the similarity of deterministic assembly processes from the national species pool across all pools. Stochastic elements were important drivers of between-pool differences at the regional-scale but the scale of these effects was also similar across most of the pools studied. The amalgamation of assembly theory into ecosystem restoration monitoring allows us to conclude with more certainty that restoration has been successful from an ecological perspective in these systems. Evaluation of these UK findings compared to those from peatlands across Europe and North America further suggests that restoring peatland pools delivers significant benefits for aquatic fauna by

  4. The endemic Patagonian vespertilionid assemblage is a depauperate ecomorphological vicariant of species-rich neotropical assemblages

    Institute of Scientific and Technical Information of China (English)

    Analía L.GIM(E)NEZ; Norberto P. GIANNINI

    2017-01-01

    Vespertilionidae is the most diverse chiropteran family,and its diversity is concentrated in warm regions of the World;however,due to physiological and behavioral adaptations,these bats also dominate bat faunas in temperate regions.Here we performed a comparative study of vespertilionid assemblages from two broad regions of the New World,the cold and harsh Patagonia,versus the remaining temperate-to-subtropical,extra-Patagonian eco-regions of the South American Southern Cone.We took an ecomorphological approach and analyzed the craniodental morphological structure of these assemblages within a phylogenetic framework.We measured 17 craniodental linear variables from 447 specimens of 22 currently recognized vespertilionid species of the study regions.We performed a multivariate analysis to define the morphofunctional space,and calculated the pattern and degree of species packing for each assemblage.We assessed the importance of phylogeny and biogeography,and their impact on depauperate (Patagonian) versus rich (extra-Patagonian) vespertilionid assemblages as determinants of morphospace structuring.We implemented a sensitivity analysis associated to small samples of rare species.The morphological patterns were determined chiefly by the evolutionary history of the family.The Patagonian assemblage can be described as a structurally similar but comparatively depauperate ecomorphological version of those assemblages from neighboring extra-Patagonian eco-regions.The Patagonian assemblage seems to have formed by successively adding populations from Northern regions that eventually speciated in the region,leaving corresponding sisters (vicariants) in extraPatagonian eco-regions that continued to be characteristically richer.Despite being structurally akin,degree of species packing in Patagonia was comparatively very low,which may reflect the effect of limited dispersal success into a harsh region for bat survival.

  5. Responses of aquatic organisms to metal pollution in a lowland river in Flanders: A comparison of diatoms and macroinvertebrates

    Energy Technology Data Exchange (ETDEWEB)

    Jonge, Maarten de [Department of Biology, Ecophysiology, Biochemistry and Toxicology Group, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium)], E-mail: maarten.dejonge@ua.ac.be; Vijver, Bart van de [Department of Bryophytes and Thallophytes, National Botanic Garden of Belgium, Domein van Bouchout, 1860 Meise (Belgium); Blust, Ronny; Bervoets, Lieven [Department of Biology, Ecophysiology, Biochemistry and Toxicology Group, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium)

    2008-12-15

    The role of macroinvertebrates and diatoms as indicator for metal pollution was investigated by assessing both biota along a metal gradient in the Belgian river the Dommel. Macroinvertebrates and diatoms were sampled in summer and winter and physical-chemical characteristics of the water were measured at four different sample periods and related to sediment characteristics. Although metal concentrations, except cadmium, in the water nowhere exceeded water quality standards, high metal concentrations were measured in the sediment, indicating historical contamination of the Dommel. At the sites that were situated downstream of the pollution source, high levels of conductivity and chloride were measured in the water. Redundancy Analysis (RDA) indicated pH, phosphate and zinc as the significant environmental variables explaining each respectively 7.7%, 11.6% and 22.6% of the macroinvertebrate community composition. Two clusters could be separated, with Gammarus pulex, Leptocerus interruptus, Baetis rhodani and Cloeon dipterum associated with low zinc concentrations and Tubificidae, Asellus aquaticus, Erpobdella sp. and Chironomus thummi-plumosus associated with higher zinc concentrations. Ammonium (10.6%), conductivity (16.5%), chloride (11.4%) and zinc (5.9%) turned out to be significant variables explaining the diatom community structure. Based on physical-chemical differences and species composition, three different groups could be separated. With this Tabellaria flocculosa and Fragilaria capucina var. rumpens were associated with low metal concentrations, Gomphonema parvulum and Nitzschia palea with elevated concentrations and Eolimna minima and Sellaphora seminulum with high zinc concentrations. In conclusion, the diatom community best reflected the metal gradient. With regard to water quality indices, those based on macroinvertebrates best followed the metal pollution gradient and were most strongly correlated with physical-chemical variables of water and

  6. Responses of aquatic organisms to metal pollution in a lowland river in Flanders: A comparison of diatoms and macroinvertebrates

    International Nuclear Information System (INIS)

    Jonge, Maarten de; Vijver, Bart van de; Blust, Ronny; Bervoets, Lieven

    2008-01-01

    The role of macroinvertebrates and diatoms as indicator for metal pollution was investigated by assessing both biota along a metal gradient in the Belgian river the Dommel. Macroinvertebrates and diatoms were sampled in summer and winter and physical-chemical characteristics of the water were measured at four different sample periods and related to sediment characteristics. Although metal concentrations, except cadmium, in the water nowhere exceeded water quality standards, high metal concentrations were measured in the sediment, indicating historical contamination of the Dommel. At the sites that were situated downstream of the pollution source, high levels of conductivity and chloride were measured in the water. Redundancy Analysis (RDA) indicated pH, phosphate and zinc as the significant environmental variables explaining each respectively 7.7%, 11.6% and 22.6% of the macroinvertebrate community composition. Two clusters could be separated, with Gammarus pulex, Leptocerus interruptus, Baetis rhodani and Cloeon dipterum associated with low zinc concentrations and Tubificidae, Asellus aquaticus, Erpobdella sp. and Chironomus thummi-plumosus associated with higher zinc concentrations. Ammonium (10.6%), conductivity (16.5%), chloride (11.4%) and zinc (5.9%) turned out to be significant variables explaining the diatom community structure. Based on physical-chemical differences and species composition, three different groups could be separated. With this Tabellaria flocculosa and Fragilaria capucina var. rumpens were associated with low metal concentrations, Gomphonema parvulum and Nitzschia palea with elevated concentrations and Eolimna minima and Sellaphora seminulum with high zinc concentrations. In conclusion, the diatom community best reflected the metal gradient. With regard to water quality indices, those based on macroinvertebrates best followed the metal pollution gradient and were most strongly correlated with physical-chemical variables of water and

  7. Effects of anthropogenic silt on aquatic macroinvertebrates and abiotic variables in streams in the Brazilian Amazon

    Energy Technology Data Exchange (ETDEWEB)

    Couceiro, Sheyla Regina Marques; Hamada, Neusa [Inst. Nacional de Pesquisas da Amazonia, Coordenacao de Pesquisas em Entomologia, Manaus, AM (Brazil); Forsberg, Bruce Rider [Inst. Nacional de Pesquisas da Amazonia, Coordenacao de Pesquisas em Entomologia, Manaus, AM (Brazil); Inst. Nacional de Pesquisas da Amazonia, Coordenacao de Pesquisas em Ecologia, Manaus, AM (Brazil); Padovesi-Fonseca, Claudia [Univ. de Brasilia, Dept. de Ecologia, Brasilia, DF (Brazil)

    2010-01-15

    Purpose: While environmental risks associated with petroleum extraction such as oil spills or leaks are relatively well known, little attention has been given to the impacts of silt. The increase in petroleum exploitation in Amazonia has resulted in sediment input to aquatic systems, with impacts on their biodiversity. Here we use a combination of field measurements and statistical analyses to evaluate the impacts of anthropogenic silt derived from the construction of roads, borrow pits, and wells during the terrestrial development of gas and oil, on macroinvertebrate communities in streams of the Urucu Petroleum Province in the Central Brazilian Amazon. Material and methods: Ten impacted and nine non-impacted streams were sampled in January, April, and November of 2007. Macroinvertebrates were sampled along a 100-m continuous reach in each stream at 10-m intervals using a dip net. Abiotic variables including, a siltation index (SI), suspended inorganic sediment (SIS), sediment color index (SCI), suspend organic sediment (SOS), pH, electrical conductivity, dissolved oxygen, temperature, water velocity, channel width, and depth, were measured at three equidistant points in each stream ({proportional_to}30-m intervals). Results and discussion: SI did not differ between impacted and undisturbed streams. SIS was higher and SCI lower (more reddish) in impacted than in non-impacted streams. SCI had a positive and SIS a negative effect on both macroinvertebrate richness and density. SIS and SCI also influenced macrophyte taxonomic composition. In impacted streams, taxonomic richness and density were 1.5 times lower than in non-impacted streams. No taxon was significantly associated with impacted streams. SIS was positively correlated with SOS and electrical conductivity while SCI was negatively correlated with SOS, electrical conductivity, and pH. The lack of difference in SI between impacted and nonimpacted streams suggests that anthropogenic sediment does not accumulate

  8. Long-Term Changes in the Water Quality and Macroinvertebrate Communities of a Subtropical River in South China

    Directory of Open Access Journals (Sweden)

    Kun Li

    2014-12-01

    Full Text Available Subtropical rivers support a highly diverse array of benthic macroinvertebrates. In this study, by combining historical data and new data, we identified specific changes in the Guanlan River, in South China, from 1981 to 2011, and evaluated the effectiveness of an ecological restoration project under highly polluted conditions. From 1981 to 2011, the water quality in the Guanlan River underwent three major stages. With the deterioration of water quality, there was an overall decrease in the species number of macroinvertebrates in the Guanlan River, an increase in macroinvertebrate density, and a reduction of the biodiversity, and a reduction of functional feeding groups. In 2011, after five years of comprehensive remediation, the Guanlan River was somewhat improved. Macroinvertebrate biodiversity in the middle reach of the Guanlan River, where a key ecological restoration engineering project was implemented, did not differ significantly from other sites. This finding indicates that the effectiveness of ecological restoration measures in highly polluted rivers, particularly at the reach-scale, is very limited and even ineffective.

  9. Richness of littoral macroinvertebrate communities in mountain ponds from NW Spain: what factors does it depend on?

    Directory of Open Access Journals (Sweden)

    Francisco Garcia-Criado

    2012-01-01

    Full Text Available Recent researches have started to provide useful information on the littoral macroinvertebrates living in European mountain ponds. However, there is still uncertainty on the factors really shaping their communities. Understanding patterns of biodiversity in these systems is essential for conservation and management purposes. In this paper, we sampled littoral macroinvertebrates at 51 mountain ponds from a wide Spanish region (Castilla y León in order to define which of a set of environmental variables were responsible for differences in richness (genus level or above. One macroinvertebrate sample was collected at each pond (in late June or early July between 2004 and 2008 by kicking and sweeping following a multihabitat time-limited sampling. Twenty-four variables measured at 39 ponds were used to generate a predictive model by multiple linear regression. This model revealed number of habitats and fish stocking as the only significant variables, showing their relative importance against variables traditionally considered to influence richness in mountain ponds and lakes (for example, altitude and pond size. Furthermore, this model accurately predicted richness when tested on a new set of twelve ponds. Additional data analyses proved that neither altitude nor habitat type significantly influenced macroinvertebrate richness, while water permanence had a slight effect (the number of taxa was slightly lower in temporary than in permanent ponds.

  10. Cryptic biodiversity in streams: a comparison of macroinvertebrate communities based on morphological and DNA barcode identifications

    Science.gov (United States)

    Species-level identifications are difficult or impossible for many larval aquatic macroinvertebrates. We described the taxonomic composition of macroinvertebrate communities from 5 coastal streams in 3 neighboring catchments in southern California. We compared taxonomic identific...

  11. Cryptic biodiversity in streams - a comparison of macroinvertebrate communities based on morphological and DNA barcode identifications

    Science.gov (United States)

    Aquatic ecologists and entomologists have long known that species-level identifications were difficult, if not impossible, for many larval macroinvertebrates collected in streams. This study describes macroinvertebrate (primarily insect) communities from five coastal streams dist...

  12. Guam Community Coral Reef Monitoring Program, Macroinvertebrate Training Surveys in Guam in 2012

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Guam community members gathered macroinvertebrate within a 25-meter x 2-meter belt transect. Members identified macroinvertebrates to species (when possible),...

  13. Ecological assessment of the Tajan river using feeding groups of benthic macroinvertebrates and biotic indices

    Directory of Open Access Journals (Sweden)

    M Sharifinia

    2012-06-01

    Full Text Available One of the best practical methods to understand ecological status of a water body and determine impacts of human intervention in reducing water quality is using benthic macroinvertebrates as assessment tools for monitoring their biological integrity and health. The Tajan River is one of the rivers of Caspian Southernsub-basin that drains the Caspian Sea. Macroinvertebrate samples were taken using Surber’s sampler (40 x 40 cm and 100µ mesh size in 45 day intervals with 3 replicates in each sampling site for a period of one year (May 2010 to May 2011. The collected organisms were preserved in 4% formalin solution and transferred to the laboratory for identification and counting. Six different functional feeding groups of macroinvertebrate e.g. Collector-gathering, Collector-filtering, Predator, Collector-gathering /Scraper, Predator/Collector-gathering and Scraper were determined. Feeding groups of Collector-gathering, Collector-filtering and Collector-gathering /Scraper were relatively dominant in comparison to other groups. Groups of Collector-filtering and Collector-gathering were dominant in slightly and heavily polluted stations, respectively. In this study population structure measures including abundance, EPT percent and the EPT and EPT/CHIR indics were mearsured. Species diversity, species richness were also determined using Shannon- Weiner, Margalef and Jacardindics. The minimum and maximum values of Hilsenhoff biotic index were observedin stations 1 (4.29 and 5 (5.57, respectively. Moreover, the highest and lowest values of BMWP/ASPT were observed in station 1 (4.51 and 5 (3.25, respectively. Evaluation of indicators revealed less water quality at stations 2, 3 and 5 which located at the lowermost of fish farms and effluent of factory. This reduction might be implicated to the effluents of water damps from fish farms running into the stream as diversity and total abundance (% of sociable macroinvertebrates decreased and that of

  14. Trace-fossil assemblages with a new ichnogenus in "spotted"

    Science.gov (United States)

    Šimo, Vladimír; Tomašových, Adam

    2013-10-01

    Highly-bioturbated "spotted" limestones and marls (Fleckenmergel-Fleckenkalk facies) of the Early Jurassic, which were deposited in broad and recurrent deep-shelf habitats of the Northern Tethys, are characterized by rare benthic carbonate-producing macroinvertebrates. To address this paradox, we analyse trace-fossil assemblages in a ~85 m-thick succession of Pliensbachian spotted deposits (Zliechov Basin, Western Carpathians). They are dominated by infaunal and semi-infaunal deposit-feeders, with 9 ichnogenera and pyritized tubes of the semi-infaunal foraminifer Bathysiphon, being dominated by Chondrites, Lamellaeichnus (new ichnogenus), and Teichichnus. Lamellaeichnus, represented by a horizontal basal cylindrical burrow and an upper row of stacked convex-up gutters, was produced by a mobile deposit-feeder inhabiting shallow tiers because it is crossed by most other trace fossils. We show that the spotty appearance of the deposits is generated by a mixture of (1) dark, organic-rich shallow- and deep-tier traces (TOC = 0.16-0.36), and (2) light grey, organic-poor mottled or structurless sediment (TOC = 0.09-0.22). The higher TOC in shallow-tier burrows of Lamellaeichnus demonstrates that uppermost sediment layers were affected by poor redox cycling. Such conditions imply a limited mixed-layer depth and inefficient nutrient recycling conditioned by hypoxic bottom-waters, allowed by poor circulation and high sedimentation rates in depocenters of the Zliechov Basin. Hypoxic conditions are further supported by (1) dominance of trace-fossils produced by infaunal deposit feeders, (2) high abundance of hypoxiatolerant agglutinated foraminifer Bathysiphon, and (3) high abundance of Chondrites with ~0.5 mm-sized branches. Oxygen-deficient bottom-conditions can thus simultaneously explain the rarity of benthic carbonate-producing macroinvertebrates and high standing abundance of tolerant soft-shell and agglutinated organisms in spotted deposits.

  15. Microplastic Effect Thresholds for Freshwater Benthic Macroinvertebrates

    Science.gov (United States)

    2018-01-01

    Now that microplastics have been detected in lakes, rivers, and estuaries all over the globe, evaluating their effects on biota has become an urgent research priority. This is the first study that aims at determining the effect thresholds for a battery of six freshwater benthic macroinvertebrates with different species traits, using a wide range of microplastic concentrations. Standardized 28 days single species bioassays were performed under environmentally relevant exposure conditions using polystyrene microplastics (20–500 μm) mixed with sediment at concentrations ranging from 0 to 40% sediment dry weight (dw). Microplastics caused no effects on the survival of Gammarus pulex, Hyalella azteca, Asellus aquaticus, Sphaerium corneum, and Tubifex spp. and no effects were found on the reproduction of Lumbriculus variegatus. No significant differences in growth were found for H. azteca, A. aquaticus, S. corneum, L. variegatus, and Tubifex spp. However, G. pulex showed a significant reduction in growth (EC10 = 1.07% sediment dw) and microplastic uptake was proportional with microplastic concentrations in sediment. These results indicate that although the risks of environmentally realistic concentrations of microplastics may be low, they still may affect the biodiversity and the functioning of aquatic communities which after all also depend on the sensitive species. PMID:29337537

  16. paleoenvironmental settings and assemblage changes

    African Journals Online (AJOL)

    Kasanzu

    shallow borehole drilled in the southern coastal basin of Tanzania with the aim of characterizing foraminifera and palynomorphs assemblage changes aiming at reconstructing ..... decline in temperature at EOT which caused the extinction of ...

  17. Effects of the “Run-of-River” Hydro Scheme on Macroinvertebrate Communities and Habitat Conditions in a Mountain River of Northeastern China

    Directory of Open Access Journals (Sweden)

    Haoran Wang

    2016-01-01

    Full Text Available The main objective of this study was to quantify the impacts of the run of river (ROR scheme on the instream habitat and macroinvertebrate community. We sampled the macroinvertebrate assemblages and collected the habitat variables above and below an ROR hydropower plant: Aotou plant in the Hailang River, China. The effects of the ROR scheme on habitat conditions were examined using regulation-related variables, most of which, particularly the hydrological variables and substrate composition, presented spatial variations along the downstream direction, contributing to heterogeneous conditions between reaches. The macroinvertebrate richness, the density and the diversity metrics showed significant decreases in the “depleted” reach compared with the upper and lower reaches. Approximately 75% of reach-averaged densities and 50% of taxa richness suffered decreases in the “depleted” reach compared with the upper reach. Furthermore, functional feeding groups also showed distinct site differences along the channel. The relative abundance of both collector-gatherers and the scrapers reduced considerably at the “depleted” sites, particularly at the site immediately downstream of the weir. The total variance in the the functional feeding group (FFG data explained by Canonical correlation analysis (CCA was more than 81.4% and the high-loadings factors were depth, flow velocity, DO and substrate composition. We demonstrated that flow diversion at the 75% level and an in-channel barrier, due to the ROR scheme, are likely to lead to poor habitat conditions and decrease both the abundance and the diversity of macroinvertebrates in reaches influenced by water diversion.

  18. Development of a local-scale urban stream assessment method using benthic macroinvertebrates: An example from the Santa Clara Basin, California

    Science.gov (United States)

    Carter, J.L.; Purcell, A.H.; Fend, S.V.; Resh, V.H.

    2009-01-01

    Research that explores the biological response to urbanization on a site-specific scale is necessary for management of urban basins. Recent studies have proposed a method to characterize the biological response of benthic macroinvertebrates along an urban gradient for several climatic regions in the USA. Our study demonstrates how this general framework can be refined and applied on a smaller scale to an urbanized basin, the Santa Clara Basin (surrounding San Jose, California, USA). Eighty-four sampling sites on 14 streams in the Santa Clara Basin were used for assessing local stream conditions. First, an urban index composed of human population density, road density, and urban land cover was used to determine the extent of urbanization upstream from each sampling site. Second, a multimetric biological index was developed to characterize the response of macroinvertebrate assemblages along the urban gradient. The resulting biological index included metrics from 3 ecological categories: taxonomic composition ( Ephemeroptera, Plecoptera, and Trichoptera), functional feeding group (shredder richness), and habit ( clingers). The 90th-quantile regression line was used to define the best available biological conditions along the urban gradient, which we define as the predicted biological potential. This descriptor was then used to determine the relative condition of sites throughout the basin. Hierarchical partitioning of variance revealed that several site-specific variables (dissolved O2 and temperature) were significantly related to a site's deviation from its predicted biological potential. Spatial analysis of each site's deviation from its biological potential indicated geographic heterogeneity in the distribution of impaired sites. The presence and operation of local dams optimize water use, but modify natural flow regimes, which in turn influence stream habitat, dissolved O2, and temperature. Current dissolved O2 and temperature regimes deviate from natural

  19. The role of macroinvertebrates for conservation of freshwater systems.

    Science.gov (United States)

    Nieto, Carolina; Ovando, Ximena M C; Loyola, Rafael; Izquierdo, Andrea; Romero, Fátima; Molineri, Carlos; Rodríguez, José; Rueda Martín, Paola; Fernández, Hugo; Manzo, Verónica; Miranda, María José

    2017-07-01

    Freshwater ecosystems are the most threatened ecosystems worldwide. Argentinian-protected areas have been established mainly to protect vertebrates and plants in terrestrial ecosystems. In order to create a comprehensive biodiverse conservation plan, it is crucial to integrate both aquatic and terrestrial systems and to include macroinvertebrates. Here, we address this topic by proposing priority areas of conservation including invertebrates, aquatic ecosystems, and their connectivity and land uses. Northwest of Argentina. We modeled the ecological niches of different taxa of macroinvertebrates such as Coleoptera, Ephemeroptera, Hemiptera, Megaloptera, Lepidoptera, Odonata, Plecoptera, Trichoptera, Acari, and Mollusca. Based on these models, we analyzed the contribution of currently established protected areas in the conservation of the aquatic biodiversity and we propose a spatial prioritization taking into account possible conflict regarding different land uses. Our analysis units were the real watersheds, to which were added longitudinal connectivity up and down the rivers. A total of 132 species were modeled in the priority area analyses. The analysis 1 showed that only an insignificant percentage of the macroinvertebrates distribution is within the protected areas in the North West of Argentina. The analyses 2 and 3 recovered similar values of protection for the macroinvertebrate species. The upper part of Bermejo, Salí-Dulce, San Francisco, and the Upper part of Juramento basins were identified as priority areas of conservation. The aquatic ecosystems need special protection and 10% or even as much as 17% of land conservation is insufficient for species of macroinvertebrates. In turn the protected areas need to combine the aquatic and terrestrial systems and need to include macroinvertebrates as a key group to sustain the biodiversity. In many cases, the land uses are in conflict with the conservation of biodiversity; however, it is possible to apply the

  20. Individual variation in habitat use in two stream fish assemblages

    Directory of Open Access Journals (Sweden)

    Luisa Resende Manna

    2015-12-01

    Full Text Available The habitat use is an individual choice that is influenced by physical conditions such as substrate type, food resources availability and adequate depth. However, habitat use is often measured only through interspecific variability because intraspecific variability is supposed to be low. Here, the differences in habitat use by two stream fish assemblages in two different environments (Brazilian rainforest and semiarid were investigated at both interspecific and intraspecific levels. We performed 55 hours of underwater observation in a 200 meters long stretch in each stream and quantified the following habitat descriptors: (i water velocity, (ii distance from the stream bank, (iii substratum, (iv water column depth, (v aquatic cover, and (vi canopy percentage. To compare intra and interspecific variability we summarized the multivariate habitat use databases using Principal Components Analysis (PCA on Euclidean distance. An Analysis of Similarity (ANOSIM was performed to test the differences in habitat use by the two assemblages. Besides, in each fish community we did an Analysis of Variance (ANOVA to test within vs between species variability for individual position on each PCA axes. To go further than these univariate tests, the differences among the species and assemblages were tested with Permutational Multivariate Analysis of Variance (PERMANOVA. The habitat use between assemblages was significantly different (ANOSIM – R=0.14; p<0.001. PERMANOVA revealed significant differences among species in both assemblages (Rainforest - F=7.25; p<0.001; semiarid - F=4.84; p<0.001. Lower F values in the semiarid assemblage revealed a higher level of intraspecific variability for this assemblage. Our findings showed high intra and interspecific variability in both stream fish assemblages and highlight the importance of measuring individual’s differences for this feature of fish biodiversity. Additionally, the versatility described for tropical

  1. Stream Macroinvertebrate Occurrence along Gradients in Organic Pollution and Eutrophication

    DEFF Research Database (Denmark)

    Friberg, Nikolai; Skriver, Jens; Larsen, Søren Erik

    2010-01-01

    We analysed a large number of concurrent samples of macroinvertebrate communities and chemical indicators of eutrophication and organic pollution [total-P, total-N, NH4-N, biological oxygen demand (BOD5)] from 594 Danish stream sites. Samples were taken over an 11-year time span as part of the Da......We analysed a large number of concurrent samples of macroinvertebrate communities and chemical indicators of eutrophication and organic pollution [total-P, total-N, NH4-N, biological oxygen demand (BOD5)] from 594 Danish stream sites. Samples were taken over an 11-year time span as part...

  2. Recovery of lotic macroinvertebrate communities from disturbance

    Science.gov (United States)

    Wallace, J. Bruce

    1990-09-01

    Ecosystem disturbances produce changes in macrobenthic community structure (abundances, biomass, and production) that persist for a few weeks to many decades. Examples of disturbances with extremely long-term effects on benthic communities include contamination by persistent toxic agents, physical changes in habitats, and altered energy inputs. Stream size, retention, and local geomorphology may ameliorate the influence of disturbances on invertebrates. Disturbances can alter food webs and may select for favorable genotypes (e.g., insecticidal resistance). Introductions of pesticides into lotic ecosystems, which do not result in major physical changes within habitats, illustrate several factors that influence invertebrate recovery time from disturbance. These include: (1) magnitude of original contamination, toxicity, and extent of continued use; (2) spatial scale of the disturbance; (3) persistence of the pesticide; (4) timing of the contamination in relation to the life history stages of the organisms; (5) vagility of populations influenced by pesticides; and (6) position within the drainage network. The ability of macroinvertebrates to recolonize denuded stream habitats may vary greatly depending on regional life histories, dispersal abilities, and position within the stream network (e.g., headwaters vs larger rivers). Although downstream drift is the most frequently cited mechanism of invertebrate recolonization following disturbance in middle- and larger-order streams, evidence is presented that shows aerial recolonization to be potentially important in headwater streams. There is an apparent stochastic element operating for aerial recolonization, depending on the timing of disturbance and flight periods of various taxa. Available evidence indicates that recolonization of invertebrate taxa without an aerial adult stage requires longer periods of time than for those that possess winged, terrestrial adult stages (i.e., most insects). Innovative, manipulative

  3. Assessment of water chemistry, habitat, and benthic macroinvertebrates at selected stream-quality monitoring sites in Chester County, Pennsylvania, 1998-2000

    Science.gov (United States)

    Reif, Andrew G.

    2004-01-01

    Biological, chemical, and habitat data have been collected from a network of sites in Chester County, Pa., from 1970 to 2003 to assess stream quality. Forty sites in 6 major stream basins were sampled between 1998 and 2000. Biological data were used to determine levels of impairment in the benthic-macroinvertebrate community in Chester County streams and relate the impairment, in conjunction with chemical and habitat data, to overall stream quality. Biological data consisted of benthic-macroinvertebrate samples that were collected annually in the fall. Water-chemistry samples were collected and instream habitat was assessed in support of the biological sampling.Most sites in the network were designated as nonimpacted or slightly impacted by human activities or extreme climatic conditions on the basis of biological-metric analysis of benthic-macroinvertebrate data. Impacted sites were affected by factors, such as nutrient enrichment, erosion and sedimentation, point discharges, and droughts and floods. Streams in the Schuylkill River, Delaware River, and East Branch Brandywine Creek Basins in Chester County generally had low nutrient concentrations, except in areas affected by wastewater-treatment discharges, and stream habitat that was affected by erosion. Streams in the West Branch Brandywine, Christina, Big Elk, and Octoraro Creek Basins in Chester County generally had elevated nutrient concentrations and streambottom habitat that was affected by sediment deposition.Macroinvertebrate communities identified in samples from French Creek, Pigeon Creek (Schuylkill River Basin), and East Branch Brandywine Creek at Glenmoore consistently indicate good stream conditions and were the best conditions measured in the network. Macroinvertebrate communities identified in samples from Trout Creek (site 61), West Branch Red Clay Creek (site 55) (Christina River Basin), and Valley Creek near Atglen (site 34) (Octoraro Creek Basin) indicated fair to poor stream conditions and

  4. Study of aquatic macroinvertebrate communities exposed to buckeye reclamation landfill drainage wastes

    International Nuclear Information System (INIS)

    Klemm, D.J.; Thoeny, W.T.; McCarthy, H.W.

    1995-01-01

    The Buckeye Reclamation Landfill (BRL), a Superfund site, incorporates approximately 50 acres of a 658 acre tract of land. The BRL consists of past underground mining voids, including some surface-mined lands, and mine refuse piles from processed bituminous coal. The area was subsequently used as a nonhazardous public and municipal solid waste landfill, and industrial sludge and liquid wastes were also deposited in an impoundment in the northern section of the landfill. The entire landfill area was completely covered with soil and revegetated in the late 1980's and early 1990's. The BRL produces acidic and highly mineralized drainage causing a widespread problem of serious mine drainage pollution in the watershed. A study was undertaken to assess the exposure of pollutants to the macroinvertebrate assemblages and to determine the extent of pollution of the BRL watershed. Samples were collected from ten sites in 1995. Nine systematic and spatial transect samples were taken at each collection site for macroinverbrates with a 595 microm mesh, modified kick net from riffle/run and glide/pool habitats of streams above and below the BRL watershed. All macroinverbrates were identified to the lowest taxonomic level possible. The levels for total Zn ranged from 22--604 microg/L; pH ranged from 4.4 to 8.1. The data distinguished the exposed sites receiving landfill leachates and sedimentation runoff from the less impacted sites

  5. Macroinvertebrate abundance, water chemistry, and wetland characteristics affect use of wetlands by avian species in Maine

    Science.gov (United States)

    Longcore, J.R.; McAuley, D.G.; Pendelton, G.W.; Bennatti, C.R.; Mingo, T.M.; Stromborg, K.L.

    2006-01-01

    Our objective was to determine use by avian species (e.g., piscivores, marsh birds, waterfowl, selected passerines) of 29 wetlands in areas with low (chemistry, basin characteristics, and avian use of different wetland types. Shallow, beaver (Castor canadensis)-created wetlands with the highest phosphorus levels and abundant and varied macrophyte assemblages supported greater densities of macroinvertebrates and numbers of duck broods (88.3% of all broods) in contrast to deep, glacial type wetlands with sparse vegetation and lower invertebrate densities that supported fewer broods (11.7%). Low pH may have affected some acid-intolerant invertebrate taxa (i.e., Ephemeroptera), but high mean numbers of Insecta per wetland were recorded from wetlands with a pH of 5.51. Other Classes and Orders of invertebrates were more abundant on wetlands with pH > 5.51. All years combined use of wetlands by broods was greater on wetlands with pH ≤ 5.51 (77.4%) in contract to wetlands with pH > 5.51 that supported 21.8% of the broods. High mean brood density was associated with mean number of Insecta per wetland. For lentic wetlands created by beaver, those habitats contained vegetative structure and nutrients necessary to provide cover to support invertebrate populations that are prey of omnivore and insectivore species. The fishless status of a few wetlands may have affected use by some waterfowl species and obligate piscivores.

  6. Influence of benthic macro-invertebrate bioturbation on the biogeochemical behaviour of uranium within freshwater sediments

    International Nuclear Information System (INIS)

    Lagauzere, S.

    2008-06-01

    In freshwater ecosystems, sediments act as an accumulation compartment for metallic pollutants as uranium. Secondary, there can also represent endogenous sources of contamination by resuspension (e.g. flood, bioturbation) or changes of metal speciation that acts upon their bioavailability. Indeed, metallic compounds can be transformed in more or less toxic or inert compounds through physico-chemical (e.g. pH, redox conditions, ionic force) and microbiological variations. These conditions are themselves under the effects of benthic macro-invertebrate activities via bioturbation processes. The main objective of this PhD was to determinate the influence of two benthic macro-invertebrate species (Chironomus riparius and Tubifex tubifex) on the distribution and the transfers of uranium within freshwater sediments. To reach this goal, laboratory experiments were performed in order to (i) assess the effects of uranium on benthic macro-invertebrates, more particularly on their bioturbation activity, (ii) determine the influence of these organisms on uranium behaviour through high resolution physico-chemical measurements (e.g. oxygen optodes, DET gel probes), and (iii) estimate the consequences of these interactions on pelagic organisms via genotoxicity measurements (micronuclei assay and molecular bio-markers analysis on Xenopus laevis). The results demonstrate that bioturbation intensity of macro-invertebrates can be affected in uranium-contaminated sediments, but the two species studied in this work show a relative tolerance. For high uranium concentrations (>100 times the geochemical background level), corresponding however to realistic concentrations in highly contaminated sites, T. tubifex worms are able to maintain a sufficient bioturbation activity that induces a high remobilization of uranium initially associated with sediments to the overlying water (factor 2 to 10). That represents therefore a potential risk for the remaining aquatic biocenose. However, by

  7. Soil macroinvertebrates along a successional gradient in central Florida

    Czech Academy of Sciences Publication Activity Database

    Frouz, Jan; Ali, A.

    2004-01-01

    Roč. 87, č. 3 (2004), s. 386-390 ISSN 0015-4040 Institutional research plan: CEZ:AV0Z6066911 Keywords : soil macroinvertebrates * successional gradient * central Florida Subject RIV: EH - Ecology, Behaviour Impact factor: 0.786, year: 2004

  8. Qualitative Macroinvertebrate Assessment of Crouch Branch, June 1999

    International Nuclear Information System (INIS)

    Specht, W.L.

    1999-01-01

    An assessment of the macroinvertebrate community of Crouch Branch was performed in June 1999 to determine if effluent from the H-02 outfall is impairing the quality of the stream. Concurrent samples were collected for metals analyses (copper and zinc). The results of the study indicate that the stream is most impaired just downstream from the H-02 outfall and that the quality of the stream biota improves with increasing distance from the outfall. Conversely, macroinvertebrate habitat quality is best just downstream from the H-02 outfall. The midreaches of the stream contain very poor habitat quality, and the lower reaches of the stream, contain habitat of intermediate quality. Although much of the stream has degraded habitat due to channel erosion and scouring, there is strong evidence to suggest that the impairment is due to elevated concentrations of copper and zinc that are present in the H-02 effluent. A comparison of macroinvertebrate data collected in 1997 to the data collected in this study indicates that the macroinvertebrate community of Crouch Branch has improved markedly in the last two years

  9. Benthic macroinvertebrate community of a fourth order stream in ...

    African Journals Online (AJOL)

    cinthia

    Full Length Research Paper. Benthic macroinvertebrate community of a fourth order stream in Kashmir Himalaya, India. Shazia Habib1* and A.R. Yousuf2. 1Department of Environmental Science, University of Kashmir, Srinagar, India. 2National Green Tribunal, Government of India, India. Received 31 December, 2013; ...

  10. Patterning and predicting aquatic macroinvertebrate diversities using artificial neural network

    NARCIS (Netherlands)

    Park, Y.S.; Verdonschot, P.F.M.; Chon, T.S.; Lek, S.

    2003-01-01

    A counterpropagation neural network (CPN) was applied to predict species richness (SR) and Shannon diversity index (SH) of benthic macroinvertebrate communities using 34 environmental variables. The data were collected at 664 sites at 23 different water types such as springs, streams, rivers,

  11. The effect of plant density on epiphytic macroinvertebrates ...

    African Journals Online (AJOL)

    The effect of variations in the density of a submerged macrophyte,Lagarosiphon ilicifolius, on epiphytic macroinvertebrate community structure in the shallow waters of a sheltered bay of Lake Kariba were investigated. The body size class distributions of a mayfly, Cloeon (Ephemeroptera: Baetidae), and the damselfly family, ...

  12. Physico-chemical conditions and macroinvertebrate fauna in the ...

    African Journals Online (AJOL)

    This paper examines the distribution of benthic macroinvertebrates in relation to physico-chemical conditions along 1 035km of the River Nile from Aswan High Dam to Al Kanater Barrage, Cairo. Total Dissolved Salts and several individual chemical variables showed positive linear regression with distance from Aswan.

  13. Ecology of benthic macroinvertebrates in the depositional biotope of ...

    African Journals Online (AJOL)

    The ecology of benthic macroinvertebrates was studied in the depositional biotope of a river in southern Nigeria in two contrasting tidally influenced fresh and brackish water stations. Forty five taxa in nineteen families representing seven major groups of benthos were recorded. The molluscan families, dominated by ...

  14. Impacts of trout on aquatic macroinvertebrates in three Drakensberg ...

    African Journals Online (AJOL)

    Further studies are recommended in order to provide additional information on seasonal variation in these patterns, as well as on density-dependent effects of trout on aquatic macroinvertebrate communities. Keywords: management, Oncorhynchus mykiss, Salmo trutta, Ukhahlamba-Drakensberg Park, waterfalls

  15. Are sugarcane leaf-detritus well colonized by aquatic macroinvertebrates?

    Directory of Open Access Journals (Sweden)

    Luciene Aparecida Leite-Rossi

    Full Text Available AIM: The aim was to compare the kinetics of decomposition and the colonization of leaf litter of two plant species, the native Talauma ovata (pinha-do-brejo and the exotic Saccharum officinarum (sugarcane, by aquatic macroinvertebrates; METHODS: From each substrate, three recipients of colonization were taken from a stream, and the specimens identified to the lowest taxonomic level on days 7, 15, 34, 44, 61 and 75. The debris was weighed at the beginning and end of the experiment and determined their cell wall fractions; RESULTS: The coefficients of mineralization indicated higher velocity decay of organic matter refractory in T. ovata. There was no difference in taxonomic structure of macroinvertebrates, between the two substrates, but the community exhibited distinct functional feeding groups in the peak of colonization, with a greater number of shredders in T. ovata. The successive states of decomposition of the two plant detritus showed distinct macroinvertebrate densities; CONCLUSIONS: The amount and state of the plant biomass were important factors influencing the density and diversity of the macroinvertebrate fauna throughout the process of organic decomposition.

  16. Analytical approaches used in stream benthic macroinvertebrate biomonitoring programs of State agencies in the United States

    Science.gov (United States)

    Carter, James L.; Resh, Vincent H.

    2013-01-01

    Biomonitoring programs based on benthic macroinvertebrates are well-established worldwide. Their value, however, depends on the appropriateness of the analytical techniques used. All United States State, benthic macroinvertebrate biomonitoring programs were surveyed regarding the purposes of their programs, quality-assurance and quality-control procedures used, habitat and water-chemistry data collected, treatment of macroinvertebrate data prior to analysis, statistical methods used, and data-storage considerations. State regulatory mandates (59 percent of programs), biotic index development (17 percent), and Federal requirements (15 percent) were the most frequently reported purposes of State programs, with the specific tasks of satisfying the requirements for 305b/303d reports (89 percent), establishment and monitoring of total maximum daily loads, and developing biocriteria being the purposes most often mentioned. Most states establish reference sites (81 percent), but classify them using State-specific methods. The most often used technique for determining the appropriateness of a reference site was Best Professional Judgment (86 percent of these states). Macroinvertebrate samples are almost always collected by using a D-frame net, and duplicate samples are collected from approximately 10 percent of sites for quality assurance and quality control purposes. Most programs have macroinvertebrate samples processed by contractors (53 percent) and have identifications confirmed by a second taxonomist (85 percent). All States collect habitat data, with most using the Rapid Bioassessment Protocol visual-assessment approach, which requires ~1 h/site. Dissolved oxygen, pH, and conductivity are measured in more than 90 percent of programs. Wide variation exists in which taxa are excluded from analyses and the level of taxonomic resolution used. Species traits, such as functional feeding groups, are commonly used (96 percent), as are tolerance values for organic pollution

  17. Experimental acidification of two biogeochemically-distinct neotropical streams: Buffering mechanisms and macroinvertebrate drift

    International Nuclear Information System (INIS)

    Ardón, Marcelo; Duff, John H.; Ramírez, Alonso; Small, Gaston E.; Jackman, Alan P.; Triska, Frank J.; Pringle, Catherine M.

    2013-01-01

    Research into the buffering mechanisms and ecological consequences of acidification in tropical streams is lacking. We have documented seasonal and episodic acidification events in streams draining La Selva Biological Station, Costa Rica. Across this forested landscape, the severity in seasonal and episodic acidification events varies due to interbasin groundwater flow (IGF). Streams that receive IGF have higher concentrations of solutes and more stable pH (∼ 6) than streams that do not receive IGF (pH ∼ 5). To examine the buffering capacity and vulnerability of macroinvertebrates to short-term acidification events, we added hydrochloric acid to acidify a low-solute, poorly buffered (without IGF) and a high-solute, well buffered stream (with IGF). We hypothesized that: 1) protonation of bicarbonate (HCO 3 − ) would neutralize most of the acid added in the high-solute stream, while base cation release from the sediments would be the most important buffering mechanism in the low-solute stream; 2) pH declines would mobilize inorganic aluminum (Ali) from sediments in both streams; and 3) pH declines would increase macroinvertebrate drift in both streams. We found that the high-solute stream neutralized 745 μeq/L (96% of the acid added), while the solute poor stream only neutralized 27.4 μeq/L (40%). Protonation of HCO 3 − was an important buffering mechanism in both streams. Base cation, Fe 2+ , and Ali release from sediments and protonation of organic acids also provided buffering in the low-solute stream. We measured low concentrations of Ali release in both streams (2-9 μeq/L) in response to acidification, but the low-solute stream released double the amount Ali per 100 μeq of acid added than the high solute stream. Macroinvertebrate drift increased in both streams in response to acidification and was dominated by Ephemeroptera and Chironomidae. Our results elucidate the different buffering mechanisms in tropical streams and suggest that low

  18. Experimental acidification of two biogeochemically-distinct neotropical streams: Buffering mechanisms and macroinvertebrate drift

    Energy Technology Data Exchange (ETDEWEB)

    Ardón, Marcelo, E-mail: ardonsayaom@ecu.edu [Department of Biology and North Carolina Center for Biodiversity, East Carolina University, Greenville, NC 27858 (United States); Duff, John H. [U.S. Geological Survey, Menlo Park, CA 94025 (United States); Ramírez, Alonso [Department of Environmental Sciences, University of Puerto Rico, San Juan, PR 00931 (Puerto Rico); Small, Gaston E. [Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, MN 55108 (United States); Jackman, Alan P. [University of California, Davis, CA 95616 (United States); Triska, Frank J. [U.S. Geological Survey, Menlo Park, CA 94025 (United States); Pringle, Catherine M. [Odum School of Ecology, University of Georgia, Athens, GA 30602 (United States)

    2013-01-15

    Research into the buffering mechanisms and ecological consequences of acidification in tropical streams is lacking. We have documented seasonal and episodic acidification events in streams draining La Selva Biological Station, Costa Rica. Across this forested landscape, the severity in seasonal and episodic acidification events varies due to interbasin groundwater flow (IGF). Streams that receive IGF have higher concentrations of solutes and more stable pH (∼ 6) than streams that do not receive IGF (pH ∼ 5). To examine the buffering capacity and vulnerability of macroinvertebrates to short-term acidification events, we added hydrochloric acid to acidify a low-solute, poorly buffered (without IGF) and a high-solute, well buffered stream (with IGF). We hypothesized that: 1) protonation of bicarbonate (HCO{sub 3}{sup −}) would neutralize most of the acid added in the high-solute stream, while base cation release from the sediments would be the most important buffering mechanism in the low-solute stream; 2) pH declines would mobilize inorganic aluminum (Ali) from sediments in both streams; and 3) pH declines would increase macroinvertebrate drift in both streams. We found that the high-solute stream neutralized 745 μeq/L (96% of the acid added), while the solute poor stream only neutralized 27.4 μeq/L (40%). Protonation of HCO{sub 3}{sup −} was an important buffering mechanism in both streams. Base cation, Fe{sup 2+}, and Ali release from sediments and protonation of organic acids also provided buffering in the low-solute stream. We measured low concentrations of Ali release in both streams (2-9 μeq/L) in response to acidification, but the low-solute stream released double the amount Ali per 100 μeq of acid added than the high solute stream. Macroinvertebrate drift increased in both streams in response to acidification and was dominated by Ephemeroptera and Chironomidae. Our results elucidate the different buffering mechanisms in tropical streams and

  19. Identifying primary stressors impacting macroinvertebrates in the Salinas River (California, USA): Relative effects of pesticides and suspended particles

    International Nuclear Information System (INIS)

    Anderson, B.S.; Phillips, B.M.; Hunt, J.W.; Connor, V.; Richard, N.; Tjeerdema, R.S.

    2006-01-01

    Laboratory dose-response experiments with organophosphate and pyrethroid pesticides, and dose-response experiments with increasing particle loads were used to determine which of these stressors were likely responsible for the toxicity and macroinvertebrate impacts previously observed in the Salinas River. Experiments were conducted with the amphipod Hyalella azteca, the baetid mayfly Procloeon sp., and the midge Chironomus dilutus (Shobanov, formerly Chironomus tentans). The results indicate the primary stressor impacting H. azteca was pesticides, including chlorpyrifos and permethrin. The mayfly Procloeon sp. was sensitive to chlorpyrifos and permethrin within the range of concentrations of these pesticides measured in the river. Chironomus dilutus were sensitive to chlorpyrifos within the ranges of concentrations measured in the river. None of the species tested were affected by turbidity as high as 1000 NTUs. The current study shows that pesticides are more important acute stressors of macroinvertebrates than suspended sediments in the Salinas River. - Pesticides are the primary stressor impacting macroinvertebrates in sections of the lower Salinas River

  20. Identifying primary stressors impacting macroinvertebrates in the Salinas River (California, USA): Relative effects of pesticides and suspended particles

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, B.S. [Department of Environmental Toxicology, University of California, Davis, CA 95616 (United States)]. E-mail: anderson@ucdavis.edu; Phillips, B.M. [Department of Environmental Toxicology, University of California, Davis, CA 95616 (United States); Hunt, J.W. [Department of Environmental Toxicology, University of California, Davis, CA 95616 (United States); Connor, V. [Division of Water Quality, State Water Resources Control Board, 1001 I. Street, Sacramento, CA 95814 (United States); Richard, N. [Division of Water Quality, State Water Resources Control Board, 1001 I. Street, Sacramento, CA 95814 (United States); Tjeerdema, R.S. [Department of Environmental Toxicology, University of California, Davis, CA 95616 (United States)

    2006-06-15

    Laboratory dose-response experiments with organophosphate and pyrethroid pesticides, and dose-response experiments with increasing particle loads were used to determine which of these stressors were likely responsible for the toxicity and macroinvertebrate impacts previously observed in the Salinas River. Experiments were conducted with the amphipod Hyalella azteca, the baetid mayfly Procloeon sp., and the midge Chironomus dilutus (Shobanov, formerly Chironomus tentans). The results indicate the primary stressor impacting H. azteca was pesticides, including chlorpyrifos and permethrin. The mayfly Procloeon sp. was sensitive to chlorpyrifos and permethrin within the range of concentrations of these pesticides measured in the river. Chironomus dilutus were sensitive to chlorpyrifos within the ranges of concentrations measured in the river. None of the species tested were affected by turbidity as high as 1000 NTUs. The current study shows that pesticides are more important acute stressors of macroinvertebrates than suspended sediments in the Salinas River. - Pesticides are the primary stressor impacting macroinvertebrates in sections of the lower Salinas River.

  1. Optimisation of the Monitoring Strategy of Macroinvertebrate Communities in the River Dender, in Relation to the EU Water Framework Directive

    Directory of Open Access Journals (Sweden)

    Tom P. D’heygere

    2002-01-01

    Full Text Available The Dender basin in Flanders (Belgium was used as a case study to implement the European Union (EU Water Framework Directive. During the last 5 years, ample research on pollution loads and ecological water quality has been done on the Dender River. In addition to biological sampling of macroinvertebrates and fish, automated measurement stations were also used to investigate the spatial-temporal variability of the physical-chemical water quality. This research revealed that the pollution of the Dender River is highly variable. The high nutrient loads result in severe algae blooms during summer, leading to very complex diurnal processes. In this paper, the monitoring strategy for the assessment of the biological water quality in the Dender basin has been reviewed in relation to the EU Water Framework Directive. For this, seasonal macroinvertebrate data were collected and assessed. General trends and hidden structures in these data were analysed by means of classification trees, using different inputs (seasons, river types, and subbasins. Validation of the results was obtained by applying statistical methods. Analysis about the presence and abundance of the macroinvertebrates revealed that there is a distinct difference between the biological water quality in the Dender stem river and its tributaries. There are also seasonal differences between the macroinvertebrate communities when the Dender and its tributaries are examined separately. An optimised monitoring strategy is proposed based on these results and the EU Water Framework Directive. This includes two monitoring campaigns in summer and winter every 3 years. Furthermore, a cyclic monitoring scheme was developed to minimise sampling efforts.

  2. Aquatic macroinvertebrates and water quality of Sandia Canyon, Los Alamos National Laboratory, December 1992--October 1993. Status report

    International Nuclear Information System (INIS)

    Cross, S.

    1994-09-01

    In the summer of 1990, an accidental spill from the TA-3 Power Plant Environment Tank released more than 3,785 liters of sulfuric acid into upper Sandia Canyon. The Biological Resource Evaluation Team (BRET) of EM-8 at Los Alamos National Laboratory (LANL) has collected aquatic samples from the stream within Sandia Canyon since then. These field studies gather water quality measurements and collect macroinvertebrates from permanent sampling sites. An earlier report by Bennett (1994) discusses previous BRET aquatic studies in Sandia Canyon. This report updates and expands Bennett's initial findings. During 1993, BRET collected water quality data and aquatic macroinvertebrates at five permanent stations within the canyon. The substrates of the upper three stations are largely sands and silts while the substrates of the two lower stations are largely rock and cobbles. The two upstream stations are located near outfalls that discharge industrial and sanitary waste effluent. The third station is within a natural cattail marsh, approximately 0.4 km (0.25 mi) downstream from Stations SC1 and SC2. Water quality parameters are slightly different at these first three stations from those expected of natural streams, suggesting slightly degraded water quality. Correspondingly, the macroinvertebrate communities at these stations are characterized by low diversities and poorly-developed community structures. The two downstream stations appear to be in a zone of recovery, where water quality parameters more closely resemble those found in natural streams of the area. Macroinvertebrate diversity increases and community structure becomes more complex at the two lower stations, which are further indications of improved water quality downstream

  3. Macroinvertebrate Richness Importance in Coastal Tropical Streams of Esmeraldas (Ecuador and Its Use and Implications in Environmental Management Procedures

    Directory of Open Access Journals (Sweden)

    Carlos Martínez-Sanz

    2014-01-01

    Full Text Available This study was aimed at determining the performance of some indices and community attributes frequently used to assess river quality and test the role of macroinvertebrate taxa richness as element of bioindication in several coastal tropical streams of western Esmeraldas (Ecuador. In addition, a macroinvertebrate taxon list of this region was provided for the first time. Thirteen sampled points distributed across nine streams were selected for this study and nineteen parameters and attributes of bioindication were tested. The differences between nonimpact and impact places were evaluated mainly using one-way analysis of variance. Jackknife 2 and Clench were used to estimate the regional richness and the quality of the inventory, respectively. Seventy taxa (principally genus and family of the main groups of macroinvertebrates were collected. Measured richness and family richness were the best metric followed by Biological Monitoring Working Party/Colombia (BMWP/Col, Odonata richness, Shannon-Weiner, and EPT richness (Ephemeroptera + Plecoptera + Trichoptera indices. Only a slight right trend (Ephemeroptera, Trichoptera, and Chironomidae attributes or incorrect performances (Average Score Per Taxon (ASPT and % EPT were showed by frequently used metrics. Finally, several recommendations were made about taxonomic level used, the ranks of quality of taxa richness, and the effort-results relationship in the field of bioindication.

  4. Responses of macroinvertebrate community metrics to a wastewater discharge in the Upper Blue River of Kansas and Missouri, USA

    Science.gov (United States)

    Poulton, Barry C.; Graham, Jennifer L.; Rasmussen, Teresa J.; Stone, Mandy L.

    2015-01-01

    The Blue River Main wastewater treatment facility (WWTF) discharges into the upper Blue River (725 km2), and is recently upgraded to implement biological nutrient removal. We measured biotic condition upstream and downstream of the discharge utilizing the macroinvertebrate protocol developed for Kansas streams. We examined responses of 34 metrics to determine the best indicators for discriminating site differences and for predicting biological condition. Significant differences between sites upstream and downstream of the discharge were identified for 15 metrics in April and 12 metrics in August. Upstream biotic condition scores were significantly greater than scores at both downstream sites in April (p = 0.02), and in August the most downstream site was classified as non-biologically supporting. Thirteen EPT taxa (Ephemeroptera, Plecoptera, Trichoptera) considered intolerant of degraded stream quality were absent at one or both downstream sites. Increases in tolerance metrics and filtering macroinvertebrates, and a decline in ratio of scrapers to filterers all indicated effects of increased nutrient enrichment. Stepwise regressions identified several significant models containing a suite of metrics with low redundancy (R2 = 0.90 - 0.99). Based on the rapid decline in biological condition downstream of the discharge, the level of nutrient removal resulting from the facility upgrade (10% - 20%) was not enough to mitigate negative effects on macroinvertebrate communities.

  5. Macroinvertebrates as indicators of fish absence in naturally fishless lakes

    Science.gov (United States)

    Schilling, Emily Gaenzle; Loftin, C.S.; Huryn, Alexander D.

    2009-01-01

    1. Little is known about native communities in naturally fishless lakes in eastern North America, a region where fish stocking has led to a decline in these habitats. 2. Our study objectives were to: (i) characterise and compare macroinvertebrate communities in fishless lakes found in two biophysical regions of Maine (U.S.A.): kettle lakes in the eastern lowlands and foothills and headwater lakes in the central and western mountains; (ii) identify unique attributes of fishless lake macroinvertebrate communities compared to lakes with fish and (iii) develop a method to efficiently identify fishless lakes when thorough fish surveys are not possible. 3. We quantified macroinvertebrate community structure in the two physiographic fishless lake types (n = 8 kettle lakes; n = 8 headwater lakes) with submerged light traps and sweep nets. We also compared fishless lake macroinvertebrate communities to those in fish-containing lakes (n = 18) of similar size, location and maximum depth. We used non-metric multidimensional scaling to assess differences in community structure and t-tests for taxon-specific comparisons between lakes. 4. Few differences in macroinvertebrate communities between the two physiographic fishless lake types were apparent. Fishless and fish-containing lakes had numerous differences in macroinvertebrate community structure, abundance, taxonomic composition and species richness. Fish presence or absence was a stronger determinant of community structure in our study than differences in physical conditions relating to lake origin and physiography. 5. Communities in fishless lakes were more speciose and abundant than in fish-containing lakes, especially taxa that are large, active and free-swimming. Families differing in abundance and taxonomic composition included Notonectidae, Corixidae, Gyrinidae, Dytiscidae, Aeshnidae, Libellulidae and Chaoboridae. 6. We identified six taxa unique to fishless lakes that are robust indicators of fish absence: Graphoderus

  6. Do landscape factors affect brownfield carabid assemblages?

    International Nuclear Information System (INIS)

    Small, Emma; Sadler, Jon P.; Telfer, Mark

    2006-01-01

    The carabid fauna of 28 derelict sites in the West Midlands (England) were sampled over the course of one growing season (April-October, 1999). The study aimed to investigate the relationship between carabid assemblages and five measures of landscape structure pertinent to derelict habitat. At each site measurements of landscape features pertinent to derelict habitat were made: (i) the proximity of habitat corridors; (ii) the density of surrounding derelict land; (iii) the distance between the site and the rural fringe; and (iv) the size of the site. Concurrent surveys of the soil characteristics, vegetation type, and land use history were conducted. The data were analysed using a combination of ordination (DCA, RDA), variance partitioning (using pRDA) and binary linear regression. The results suggest that:1.There is very little evidence that the carabid assemblages of derelict sites were affected by landscape structure, with assemblages instead being principally related to within-site habitat variables, such as site age (since last disturbance), substrate type and vegetation community. 2.No evidence was found to support the hypothesis that sites away from railway corridors are more impoverished in their carabid fauna than sites on corridors. 3.There are some suggestions from this study that rarer and non-flying specialist species may be affected by isolation, taking longer to reach sites. We infer from this that older sites with retarded succession, and sites in higher densities of surrounding derelict land may eventually become more species rich and that these sites may be important for maintaining populations of rarer and flightless species. 4.Conservation efforts to maintain populations of these species should focus principally on habitat quality issues, such as maintaining early successional habitats that have a diversity of seed producing annuals and perennial plants and enhancing substrate variability rather than landscape issues

  7. Integral measurements on Caliban and Prospero assemblies for nuclear data validation; Mesures integrales sur les assemblages Caliban et Prospero pour la validation des donnees nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Casoli, P.; Authier, N.; Richard, B. [CEA Valduc, 21 - Is-sur-Tille (France); Ducauze-Philippe, M.; Cartier, J. [CEA Bruyeres-le-Chatel, 91 (France)

    2011-07-15

    How can the quality of nuclear data libraries be checked? Performing reference experiments also called benchmarks allows the testing of evaluated data. During these experiments, integral values such as reaction rates or neutron effective multiplication coefficients are measured. In this paper, the principles of benchmark construction are explained and illustrated with several works performed on the CALIBAN et PROSPERO critical assemblies operated by the Valduc center: benchmarks for dosimetry, activation reactions studies, neutron noise measurements. (authors)

  8. Littoral macroinvertebrates of acidified lakes in the Bohemian Forest

    Czech Academy of Sciences Publication Activity Database

    Ungermanová, L.; Kolaříková, K.; Stuchlík, E.; Senoo, T.; Horecký, J.; Kopáček, Jiří; Chvojka, P.; Tátosová, J.; Bitušík, P.; Fjellheim, A.

    2014-01-01

    Roč. 69, č. 9 (2014), s. 1190-1201 ISSN 0006-3088 R&D Projects: GA ČR(CZ) GA526/09/0567; GA ČR(CZ) GA206/07/1200 Grant - others:EC(XE) EURO-LIMPACS GOCE-CT-2003-505540 Institutional support: RVO:60077344 Keywords : lakes * macroinvertebrates * acidification * recovery * forest catchment Subject RIV: DJ - Water Pollution ; Quality Impact factor: 0.827, year: 2014

  9. Trophic structure of macroinvertebrates in tropical pasture streams

    Directory of Open Access Journals (Sweden)

    Bruna Neves da Silveira-Manzotti

    Full Text Available Abstract: Aim The aim of this study was to describe the diet of stream macroinvertebrates and to determine their trophic groups. Methods Invertebrates were sampled with D nets in three pasture streams. They were identified to genus level and submitted to gut content analysis, except for fluid feeders such as hemipterans, to which diet data was obtained from the literature. Trophic groups were determined based on a similarity analysis using the Bray-Curtis similarity coefficient. Results Five trophic groups were defined: fine-detritivores (feed mostly on fine particulate organic matter - FPOM, coarse-detritivores/herbivores (feed mostly on coarse particulate organic matter - CPOM - and plant material, omnivores, specialist-predators (prey upon aquatic insects only, and generalist-predators. Ephemeroptera, Diptera (except Tanypodinae, Coleoptera, and Trichoptera (except Smicridea were detritivores. The caddis Macronema (Trichoptera fed exclusively on plant detritus and Tanypodinae and Smicridea were classified as omnivores. The odonate families Calopterygidae and Gomphidae were classified as specialist-predators, while Macrobrachium (Decapoda, Belostoma, and Limnocoris (Hemiptera were generalist-predators. Conclusions The great quantity and frequency of occurrence of FPOM consumed by most taxa highlight the importance of this food resource for macroinvertebrate communities from tropical streams. Furthermore, observed variations on trophic group assignment for some taxa indicate the generalist and opportunistic nature of these aquatic invertebrates. Such findings reinforce the importance of conducting gut content analysis on macroinvertebrates to understand their role in the structure and functioning of tropical streams.

  10. POP bioaccumulation in macroinvertebrates of alpine freshwater systems

    International Nuclear Information System (INIS)

    Bizzotto, E.C.; Villa, S.; Vighi, M.

    2009-01-01

    This study serves to investigate the uptake of POPs in the different trophic levels (scrapers, collectors, predators, shredders) of macroinvertebrate communities sampled from a glacial and a non-glacial stream in the Italian Alps. The presented results show that the contaminant concentrations in glacial communities are generally higher compared to those from non-glacial catchments, highlighting the importance of glaciers as temporary sinks of atmospherically transported pollutants. Moreover, the data also suggests that in mountain systems snow plays an important role in influencing macroinvertebrate contamination. The main chemical uptake process to the macroinvertebrates is considered to be bioconcentration from water, as similar contaminant profiles were observed between the different trophic levels. The role of biomagnification/bioaccumulation is thought to be absent or negligible. The enrichment of chemicals observed in the predators is likely to be related to their greater lipid content compared to that of other feeding groups. - Influence of POP release in glacial-fed streams, enhanced by global warming, on pristine aquatic ecosystems.

  11. Public Sphere as Digital Assemblage

    DEFF Research Database (Denmark)

    Salovaara-Moring, Inka

    the 1990s onwards digitalization brought concepts of network and complexity into the theoretical discourse. This relational turn changed the social ontology of the public sphere into a dynamic and complex system, erasing the division between the fields of reality (the world), representation (discourse......Normative theories of public sphere have struggled with the topic of materiality. The historical narrative of the ‘public sphere’ situated the phenomenon in specific spaces, where practices (public deliberation) and language (discourse) constructed political agencies, and further publics. From......), and subjectivity (agency). This changed the public sphere into an assemblage consisting of both human and non-human actors interactingin a highly dynamic, networked environment. This paper proposes a framework for considering this new materiality in the field of the public sphere: the assemblage and complexity...

  12. DEVELOPMENT OF A STREAM BENTHIC MACROINVERTEBRATE INTEGRITY INDEX (SBMII) FOR WADEABLE STREAMS IN THE MID-ATLANTIC HIGHLANDS REGION

    Science.gov (United States)

    The Stream Benthic Macroinvertebrate Integrity Index (SBMII), a multimetric biotic index for assessing biological conditions of wadeable streams, was developed using seven macroinvertebrate metrics (Ephemeroptera richness, Plecoptera richness, Trichoptera richness, Collector-Filt...

  13. Habitat segregation in fish assemblages

    OpenAIRE

    Ibbotson, A.T.

    1990-01-01

    The segregation of habitats of fish assemblages found in the chalk streams and rivers within the Wessex, South West and Southern Water Authority boundaries in southern England have been examined. Habitat segregation is the most frequent type of resource partitioning in natural communities. The habitat of individual fish species will be defined in order to determine the following: (1) the requirements of each species in terms of depth, current velocity, substrate, cover etc.; (2) identify the ...

  14. A Europe-wide system for assessing the quality of rivers using macroinvertebrates: the AQEM Project* and its importance for southern Europe (with special emphasis on Italy

    Directory of Open Access Journals (Sweden)

    Joanna L. KEMP

    2001-09-01

    Full Text Available The AQEM Project aims to develop a Europe-wide system for monitoring the ecological quality of rivers using macroinvertebrates, to satisfy the requirements of the EU Water Framework Directive. Three main types of anthropogenic perturbation are being investigated: morphological degradation, water (organic pollution and acidification (the last is not under investigation in Italy. The selection of reference and impaired study sites is discussed. Particular attention is paid to the problems encountered when defining reference conditions. The initial stages of the project highlighted the lack of a Europe-wide definition of river types. The future development of such a typology from the AQEM database is discussed. The standard AQEM data gathering methods are presented, from background information about sites to the microhabitat-based macroinvertebrate sampling method. The extended fieldwork methods used in Italy are described. These included the separate analysis of the invertebrate assemblages from each replicate, the recording of additional microhabitat variables for each replicate and the completion of large-scale survey techniques for each site (including RHS. The extended method was designed to enhance the important ecological information available from the dataset, particularly relevant in Italy where significant gaps exist in the taxonomic and ecological knowledge of many macroinvertebrate taxa. Preliminary and expected findings are presented, including examples of the range and habitat selection of two species of Ephemeroptera endemic to Italy, as well as data relating to the number of taxa found at a site with increasing numbers of microhabitat replicates taken. The importance of the AQEM Project not only for biomonitoring, but also for ecology, taxonomy and conservation, in Italy and for the south of Europe in general, is emphasised.

  15. Macroinvertebrate-based assessment of biological condition at selected sites in the Eagle River watershed, Colorado, 2000-07

    Science.gov (United States)

    Zuellig, Robert E.; Bruce, James F.; Healy, Brian D.; Williams, Cory A.

    2010-01-01

    The U.S. Geological Survey (USGS), in cooperation with the Colorado River Water Conservation District, Eagle County, Eagle River Water and Sanitation District, Upper Eagle Regional Water Authority, Colorado Department of Transportation, City of Aurora, Town of Eagle, Town of Gypsum, Town of Minturn, Town of Vail, Vail Resorts, Colorado Springs Utilities, Denver Water, and the U.S. Department of Agriculture Forest Service (FS), compiled macroinvertebrate (73 sites, 124 samples) data previously collected in the Eagle River watershed from selected USGS and FS studies, 2000-07. These data were analyzed to assess the biological condition (that is, biologically ?degraded? or ?good?) at selected sites in the Eagle River watershed and determine if site class (for example, urban or undeveloped) described biological condition. An independently developed predictive model was applied to calculate a site-specific measure of taxonomic completeness for macroinvertebrate communities, where taxonomic completeness was expressed as the ratio of observed (O) taxa to those expected (E) to occur at each site. Macroinvertebrate communities were considered degraded at sites were O/E values were less than 0.80, indicating that at least 20 percent of expected taxa were not observed. Sites were classified into one of four classes (undeveloped, adjacent road or highway or both, mixed, urban) using a combination of riparian land-cover characteristics, examination of topographic maps and aerial imagery, screening for exceedances in water-quality standards, and best professional judgment. Analysis of variance was used to determine if site class accounted for variability in mean macroinvertebrate O/E values. Finally, macroinvertebrate taxa observed more or less frequently than expected at urban sites were indentified. This study represents the first standardized assessment of biological condition of selected sites distributed across the Eagle River watershed. Of the 73 sites evaluated, just over

  16. Mass coral bleaching causes biotic homogenization of reef fish assemblages.

    Science.gov (United States)

    Richardson, Laura E; Graham, Nicholas A J; Pratchett, Morgan S; Eurich, Jacob G; Hoey, Andrew S

    2018-04-06

    Global climate change is altering community composition across many ecosystems due to nonrandom species turnover, typically characterized by the loss of specialist species and increasing similarity of biological communities across spatial scales. As anthropogenic disturbances continue to alter species composition globally, there is a growing need to identify how species responses influence the establishment of distinct assemblages, such that management actions may be appropriately assigned. Here, we use trait-based analyses to compare temporal changes in five complementary indices of reef fish assemblage structure among six taxonomically distinct coral reef habitats exposed to a system-wide thermal stress event. Our results revealed increased taxonomic and functional similarity of previously distinct reef fish assemblages following mass coral bleaching, with changes characterized by subtle, but significant, shifts toward predominance of small-bodied, algal-farming habitat generalists. Furthermore, while the taxonomic or functional richness of fish assemblages did not change across all habitats, an increase in functional originality indicated an overall loss of functional redundancy. We also found that prebleaching coral composition better predicted changes in fish assemblage structure than the magnitude of coral loss. These results emphasize how measures of alpha diversity can mask important changes in the structure and functioning of ecosystems as assemblages reorganize. Our findings also highlight the role of coral species composition in structuring communities and influencing the diversity of responses of reef fishes to disturbance. As new coral species configurations emerge, their desirability will hinge upon the composition of associated species and their capacity to maintain key ecological processes in spite of ongoing disturbances. © 2018 John Wiley & Sons Ltd.

  17. Marine heatwaves and optimal temperatures for microbial assemblage activity.

    Science.gov (United States)

    Joint, Ian; Smale, Dan A

    2017-02-01

    The response of microbial assemblages to instantaneous temperature change was measured in a seasonal study of the coastal waters of the western English Channel. On 18 occasions between November 1999 and December 2000, bacterial abundance was assessed and temperature responses determined from the incorporation of 3 H leucine, measured in a temperature gradient from 5°C to 38°C. Q 10 values varied, being close to 2 in spring and summer but were >3 in autumn. There was a seasonal pattern in the assemblage optimum temperature (T opt ), which was out of phase with sea surface temperature. In July, highest 3 H-leucine incorporation rates were measured at temperatures that were only 2.8°C greater than ambient sea surface temperature but in winter, T opt was ∼20°C higher than the ambient sea surface temperature. Sea surface temperatures for the adjacent English Channel and Celtic Sea for 1982-2014 have periodically been >3°C higher than climatological mean temperatures. This suggests that discrete periods of anomalously high temperatures might be close to, or exceed, temperatures at which maximum microbial assemblage activity occurs. The frequency and magnitude of marine heatwaves are likely to increase as a consequence of anthropogenic climate change and extreme temperatures may influence the role of bacterial assemblages in biogeochemical processes. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  18. Spatial and temporal changes of benthic macroinvertebrate assemblages in acidified streams in the Bohemian Forest (Czech Republic)

    Czech Academy of Sciences Publication Activity Database

    Svobodová, Jana; Matěna, Josef; Kopáček, Jiří; Poláková, S.; Vrba, J.

    2012-01-01

    Roč. 34, č. 1 (2012), s. 157-172 ISSN 0165-0424. [European Congress of Entomology /9./. Budapest, 22.08.2010-27.08.2010] R&D Projects: GA ČR(CZ) GA206/07/1200 Institutional research plan: CEZ:AV0Z60170517 Keywords : atmospheric acidification * stream recovery * Lake Laka * Lake Čertovo Subject RIV: EH - Ecology, Behaviour Impact factor: 0.358, year: 2012

  19. A study of the effects of implementing agricultural best management practices and in-stream restoration on suspended sediment, stream habitat, and benthic macroinvertebrates at three stream sites in Surry County, North Carolina, 2004-2007-Lessons learned

    Science.gov (United States)

    Smith, Douglas G.; Ferrell, G.M.; Harned, Douglas A.; Cuffney, Thomas F.

    2011-01-01

    The effects of agricultural best management practices and in-stream restoration on suspended-sediment concentrations, stream habitat, and benthic macroinvertebrate assemblages were examined in a comparative study of three small, rural stream basins in the Piedmont and Blue Ridge Physiographic Provinces of North Carolina and Virginia between 2004 and 2007. The study was designed to assess changes in stream quality associated with stream-improvement efforts at two sites in comparison to a control site (Hogan Creek), for which no improvements were planned. In the drainage basin of one of the stream-improvement sites (Bull Creek), several agricultural best management practices, primarily designed to limit cattle access to streams, were implemented during this study. In the drainage basin of the second stream-improvement site (Pauls Creek), a 1,600-foot reach of the stream channel was restored and several agricultural best management practices were implemented. Streamflow conditions in the vicinity of the study area were similar to or less than the long-term annual mean streamflows during the study. Precipitation during the study period also was less than normal, and the geographic distribution of precipitation indicated drier conditions in the southern part of the study area than in the northern part. Dry conditions during much of the study limited opportunities for acquiring high-flow sediment samples and streamflow measurements. Suspended-sediment yields for the three basins were compared to yield estimates for streams in the southeastern United States. Concentrations of suspended sediment and nutrients in samples from Bull Creek, the site where best management practices were implemented, were high compared to the other two sites. No statistically significant change in suspended-sediment concentrations occurred at the Bull Creek site following implementation of best management practices. However, data collected before and after channel stabilization at the Pauls

  20. Spatial and seasonal patterns of ichthyoplankton assemblages in the Haizhou Bay and its adjacent waters of China

    Science.gov (United States)

    Li, Zengguang; Ye, Zhenjiang; Wan, Rong

    2015-12-01

    Surveys were conducted in five voyages in Haizhou Bay and its adjacent coastal area from March to December 2011 during full moon spring tides. The ichthyoplankton assemblages and the environmental factors that affect their spatial and seasonal patterns were determined. Totally 35 and 12 fish egg and larvae taxa were identified, respectively. Over the past several decades, the egg and larval species composition has significantly changed in Haizhou Bay and its adjacent waters, most likely corresponding with the alteration of fishery resources, which are strongly affected by anthropogenic activities and climate change. The Bray-Curtis dissimilarity index identified four assemblages: near-shore bay assemblage, middle bay assemblage and two closely related assemblages (near-shore/middle bay assemblage and middle/edge of bay assemblage). The primary species of each assemblage principally reflected the spawning strategies of adult fish. The near-shore bay assemblage generally occurred in near-shore bay, with depths measuring ichthyoplankton in each assemblage were determined by interactions between biological behavioral traits and oceanographic features, particularly the variation of local conditions within the constraint of a general reproductive strategy. The results of Spearman's rank correlation analysis indicated that both fish egg and larval abundance were positively correlated with depth, which is critical to the oceanographic features in Haizhou Bay.

  1. Macroinvertebrate fauna associated with Pistia stratiotes and Nymphoides indica in subtropical lakes (south Brazil

    Directory of Open Access Journals (Sweden)

    EF. Albertoni

    Full Text Available This study was carried out at the Biguás and Polegar lakes, both small environments but at different successional stages. The main objective was to characterize the macroinvertebrate community associated to the aquatic macrophyte stand in each lake in order for this community, the environmental conditions and their water quality to interact. The samples were taken in 2003. The abiotic variables of N and P totals, the temperature, electrical conductivity, pH and dissolved oxygen, as well as the determined clorophyll a concentration were measured. Macroinvertebrates were sampled with a 500 µ mesh size net, separated under a stereomicroscope and identified at the lowest possible taxonomic level, and their densities were shown as the number of individuals per 100 g of macrophyte dry weight. The Shannon-Wiener Diversity Index (H', Pielou evenness (J, frequency of occurrence, abundance and taxa richness were calculated for each invertebrate community. The Lago dos Biguás is undergoing a process of eutrophication and during the study presented a large Pistia stratiotes stand. The Lago Polegar is oligotrophic and had only a small Nymphoides indica bankwe. The macrophyte associated invertebrate communities in each lake were considered significantly different (p < 0.05. Sixty seven taxa were found for the Lago dos Biguás and 32 for the Lago Polegar. For both lakes, most of the taxa were considered rare, with a low dominance in a few months. The taxa with highest densities at Lago dos Biguás were Chironomidae, Daphniidae and Cyclopidae, and Oligochaeta, Chironomidae and Coenagrionidae for Lago Polegar.

  2. Macro-Invertebrate Decline in Surface Water Polluted with Imidacloprid: A Rebuttal and Some New Analyses

    Science.gov (United States)

    Vijver, Martina G.; van den Brink, Paul J.

    2014-01-01

    Imidacloprid, the largest selling insecticide in the world, has received particular attention from scientists, policymakers and industries due to its potential toxicity to bees and aquatic organisms. The decline of aquatic macro-invertebrates due to imidacloprid concentrations in the Dutch surface waters was hypothesised in a recent paper by Van Dijk, Van Staalduinen and Van der Sluijs (PLOS ONE, May 2013). Although we do not disagree with imidacloprid's inherent toxicity to aquatic organisms, we have fundamental concerns regarding the way the data were analysed and interpreted. Here, we demonstrate that the underlying toxicity of imidacloprid in the field situation cannot be understood except in the context of other co-occurring pesticides. Although we agree with Van Dijk and co-workers that effects of imidacloprid can emerge between 13 and 67 ng/L we use a different line of evidence. We present an alternative approach to link imidacloprid concentrations and biological data. We analysed the national set of chemical monitoring data of the year 2009 to estimate the relative contribution of imidacloprid compared to other pesticides in relation to environmental quality target and chronic ecotoxicity threshold exceedances. Moreover, we assessed the relative impact of imidacloprid on the pesticide-induced potential affected fractions of the aquatic communities. We conclude that by choosing to test a starting hypothesis using insufficient data on chemistry and biology that are difficult to link, and by ignoring potential collinear effects of other pesticides present in Dutch surface waters Van Dijk and co-workers do not provide direct evidence that reduced taxon richness and abundance of macroinvertebrates can be attributed to the presence of imidacloprid only. Using a different line of evidence we expect ecological effects of imidacloprid at some of the exposure profiles measured in 2009 in the surface waters of the Netherlands. PMID:24587069

  3. Macro-invertebrate decline in surface water polluted with imidacloprid: a rebuttal and some new analyses.

    Directory of Open Access Journals (Sweden)

    Martina G Vijver

    Full Text Available Imidacloprid, the largest selling insecticide in the world, has received particular attention from scientists, policymakers and industries due to its potential toxicity to bees and aquatic organisms. The decline of aquatic macro-invertebrates due to imidacloprid concentrations in the Dutch surface waters was hypothesised in a recent paper by Van Dijk, Van Staalduinen and Van der Sluijs (PLOS ONE, May 2013. Although we do not disagree with imidacloprid's inherent toxicity to aquatic organisms, we have fundamental concerns regarding the way the data were analysed and interpreted. Here, we demonstrate that the underlying toxicity of imidacloprid in the field situation cannot be understood except in the context of other co-occurring pesticides. Although we agree with Van Dijk and co-workers that effects of imidacloprid can emerge between 13 and 67 ng/L we use a different line of evidence. We present an alternative approach to link imidacloprid concentrations and biological data. We analysed the national set of chemical monitoring data of the year 2009 to estimate the relative contribution of imidacloprid compared to other pesticides in relation to environmental quality target and chronic ecotoxicity threshold exceedances. Moreover, we assessed the relative impact of imidacloprid on the pesticide-induced potential affected fractions of the aquatic communities. We conclude that by choosing to test a starting hypothesis using insufficient data on chemistry and biology that are difficult to link, and by ignoring potential collinear effects of other pesticides present in Dutch surface waters Van Dijk and co-workers do not provide direct evidence that reduced taxon richness and abundance of macroinvertebrates can be attributed to the presence of imidacloprid only. Using a different line of evidence we expect ecological effects of imidacloprid at some of the exposure profiles measured in 2009 in the surface waters of the Netherlands.

  4. Recent saltmarsh foraminiferal assemblages from Iceland

    Science.gov (United States)

    Lübbers, Julia; Schönfeld, Joachim

    2018-01-01

    This study reports for the first time boreal to subarctic intertidal foraminiferal assemblages from saltmarshes at Borgarnes and Faskrudsfjördur on Iceland. The composition of living and dead foraminiferal assemblages was investigated along transects from the tidal flat to the highest reach of halophytic plants. The foraminiferal assemblages from Borgarnes showed 18 species in the total foraminiferal assemblage of which only 7 species were recorded in the living fauna. The assemblages were dominated by agglutinated taxa, whereas 3 calcareous species were recorded, of which only Haynesina orbicularis was found in the living fauna. The distribution limit of calcifying species corresponds to the lower boundary of the lower saltmarsh vegetation zone. Furthermore, calcareous tests showed many features of dissolution, which is an indication of a carbonate corrosive environment. The species forming the dead assemblages were mainly derived from the ambient intertidal areas and were displaced by tidal currents into the saltmarsh. The foraminiferal assemblages from Faskrudsfjördur showed two species, of which only one species was recorded in the living fauna. The assemblage was dominated by the agglutinated foraminifer Trochaminita irregularis. The foraminiferal species recorded on Iceland were the same as commonly found elsewhere in Europa. Since no species was found which is endemic to North America, Iceland is considered part of the European bio province. The foraminiferal could have been immigrated to Iceland from Europe through warm water currents, migratory birds or marine traffic since the last Ice Age.

  5. Responses of macroinvertebrates and local environment to short-term commercial sand dredging practices in a flood-plain lake.

    Science.gov (United States)

    Meng, Xingliang; Jiang, Xiaoming; Li, Zhengfei; Wang, Jun; Cooper, Keith M; Xie, Zhicai

    2018-08-01

    In parts of the developing world, the expansion of industrial sand mining activities has led to serious environmental concerns. However, current understanding of the effects of this activity on an inland water ecosystem remains limited. Herein, we choose the "most affected" lake in China (Dongting Lake), to assess short-term (1year) effects of sand dredging on key environmental parameters and on the structure of the macroinvertebrate assemblage. Within the dredged area we observed increases in water depth (on average 2.17m), turbidity and changes in sediment composition (e.g., increase in % medium sand, and a decrease in % clay). In addition, dredging was associated with a 50 % reduction in taxa richness, Simpson and Shannon-Wiener indices, and a 72 and 99 % reduction in abundance and biomass, respectively. Indirect effects were also observed in the zone surrounding the extraction sites (ca. 500m), most likely as a result of the dredging processes (e.g., sediment screening and overspill) and water flow. No such effects were observed at a nearby reference site. The direct removal of sediment and indirect alteration of physical conditions (e.g., water depth, turbidity and sediment composition) appear to be the most likely cause of variations in the benthic community. Implications of our findings for the planning, management and monitoring of sand dredging in inland waters are discussed. Copyright © 2018 Elsevier B.V. All rights reserved.

  6. Aquatic-macroinvertebrate communities of Prairie-Pothole wetlands and lakes under a changed climate

    Science.gov (United States)

    McLean, Kyle I.; Mushet, David M.; Renton, David A.; Stockwell, Craig A.

    2016-01-01

    Understanding how aquatic-macroinvertebrate communities respond to changes in climate is important for biodiversity conservation in the Prairie Pothole Region and other wetland-rich landscapes. We sampled macroinvertebrate communities of 162 wetlands and lakes previously sampled from 1966 to 1976, a much drier period compared to our 2012–2013 sampling timeframe. To identify possible influences of a changed climate and predation pressures on macroinvertebrates, we compared two predictors of aquatic-macroinvertebrate communities: ponded-water dissolved-ion concentration and vertebrate-predator presence/abundance. Further, we make inferences of how macroinvertebrate communities were structured during the drier period when the range of dissolved-ion concentrations was much greater and fish occurrence in aquatic habitats was rare. We found that aquatic-macroinvertebrate community structure was influenced by dissolved-ion concentrations through a complex combination of direct and indirect relationships. Ion concentrations also influenced predator occurrence and abundance, which indirectly affected macroinvertebrate communities. It is important to consider both abiotic and biotic gradients when predicting how invertebrate communities will respond to climate change. Generally, in the wetlands and lakes we studied, freshening of ponded water resulted in more homogenous communities than occurred during a much drier period when salinity range among sites was greater.

  7. Use of an oscillation technique to measure effective cross-sections of fissionable samples in critical assemblies; Mesure des sections efficaces effectives d'echantillons fissiles par une methode d'oscillation dans les-assemblages critiques

    Energy Technology Data Exchange (ETDEWEB)

    Tretiakoff, O; Vidal, R; Carre, J C; Robin, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    The authors describe the technique used to measure the effective absorption and neutron-yield cross-sections of a fissionable sample. These two values are determined by analysing the signals due to the variation in reactivity (over-all signal) and the local perturbation in the flux (local signal) produced by the oscillating sample. These signals are standardized by means of a set of samples containing quantities of fissionable material ({sup 235}U) and an absorber, boron, which are well known. The measurements are made for different neutron spectra characterized by lattice parameters which constitute the central zone within which the sample moves. This technique is used to study the effective cross-sections of uranium-plutonium alloys for different heavy-water and graphite lattices in the MINERVE and MARIUS critical assemblies. The same experiments are carried out on fuel samples of different irradiations in order to determine the evolution of effective cross-sections as a function of the spectrum and the irradiations. (authors) [French] On decrit la methode utilisee pour mesurer les sections efficaces effectives d'absorption et de production de neutrons d'un echantillon fissile. Ces deux grandeurs sont determinees en analysant les signaux dus a la variation de reactivite (signal global) et a la perturbation locale de flux (signal local) produits par l'echantillon oscillant. Ces signaux sont etalonnes a l'aide d'un jeu d'echantillons dont les teneurs en materiau fissile ({sup 235}U) et en absorbeur (bore) sont bien connues. Les mesures sont realisees pour differents spectres de neutrons caracterises par les parametres du reseau constituant la zone centrale a l'interieur de laquelle se deplace l'echantillon. A l'aide de cette methode on etudie les sections efficaces effectives d'alliage uranium-plutonium pour differents reseaux a eau lourde et a graphite dans les assemblages crtiques MINERVE et MARIUS. Les memes experiences sont effectuees sur des echantillons de

  8. Prey distribution, physical habitat features, and guild traits interact to produce contrasting shorebird assemblages among foraging patches.

    Directory of Open Access Journals (Sweden)

    Beth M VanDusen

    Full Text Available Worldwide declines in shorebird populations, driven largely by habitat loss and degradation, motivate environmental managers to preserve and restore the critical coastal habitats on which these birds depend. Effective habitat management requires an understanding of the factors that determine habitat use and value to shorebirds, extending from individuals to the entire community. While investigating the factors that influenced shorebird foraging distributions among neighboring intertidal sand flats, we built upon species-level understandings of individual-based, small-scale foraging decisions to develop more comprehensive guild- and community-level insights. We found that densities and community composition of foraging shorebirds varied substantially among elevations within some tidal flats and among five flats despite their proximity (all located within a 400-m stretch of natural, unmodified inlet shoreline. Non-dimensional multivariate analyses revealed that the changing composition of the shorebird community among flats and tidal elevations correlated significantly (ρ(s = 0.56 with the spatial structure of the benthic invertebrate prey community. Sediment grain-sizes affected shorebird community spatial patterns indirectly by influencing benthic macroinvertebrate community compositions. Furthermore, combining sediment and macroinvertebrate information produced a 27% increase in correlation (ρ(s = 0.71 with shorebird assemblage patterns over the correlation of the bird community with the macroinvertebrate community alone. Beyond its indirect effects acting through prey distributions, granulometry of the flats influenced shorebird foraging directly by modifying prey availability. Our study highlights the importance of habitat heterogeneity, showing that no single patch type was ideal for the entire shorebird community. Generally, shorebird density and diversity were greatest at lower elevations on flats when they became exposed; these

  9. Patterns of Assemblage Structure Indicate a Broader Conservation Potential of Focal Amphibians for Pond Management.

    Directory of Open Access Journals (Sweden)

    Elin Soomets

    Full Text Available Small freshwater ponds host diverse and vulnerable biotic assemblages but relatively few conspicuous, specially protected taxa. In Europe, the amphibians Triturus cristatus and Pelobates fuscus are among a few species whose populations have been successfully restored using pond restoration and management activities at the landscape scale. In this study, we explored whether the ponds constructed for those two target species have wider conservation significance, particularly for other species of conservation concern. We recorded the occurrence of amphibians and selected aquatic macro-invertebrates (dragonflies; damselflies; diving beetles; water scavenger beetles in 66 ponds specially constructed for amphibians (up to 8 years post construction and, for comparison, in 100 man-made ponds (created by local people for cattle or garden watering, peat excavation, etc. and 65 natural ponds in Estonia. We analysed nestedness of the species assemblages and its dependence on the environment, and described the co-occurrence patterns between the target amphibians and other aquatic species. The assemblages in all ponds were significantly nested, but the environmental determinants of nestedness and co-occurrence of particular species differed among pond types. Constructed ponds were most species-rich irrespective of the presence of the target species; however, T. cristatus was frequent in those ponds and rare elsewhere, and it showed nested patterns in every type of pond. We thus conclude that pond construction for the protected amphibians can serve broader habitat conservation aims in the short term. However, the heterogeneity and inconsistent presence of species of conservation concern observed in other types of ponds implies that long-term perspectives on pond management require more explicit consideration of different habitat and biodiversity values. We also highlight nestedness analysis as a tool that can be used for the practical task of selecting focal

  10. Environmental drivers of the benthic macroinvertebrates community in a hypersaline estuary (Northeastern Brazil

    Directory of Open Access Journals (Sweden)

    Carlinda Railly Ferreira Medeiros

    Full Text Available Abstract Introduction The estuarine community of benthic macroinvertebrates spatially varies in response to changes in environmental variables in these ecosystems. Understanding this variability helps our understanding the mechanisms structuring these communities. Aim Assess the structural aspects of the benthic macroinvertebrate community in a hypersaline estuary, and to relate to environmental variables that influence the community structure along the estuary. Methods The study was conducted at Tubarão river estuary in May 2015. We sampled two estuarine areas (upper and lower, and in each zone were sampled six points composed of two replicas, one sampled in sandy bottom and the other in muddy bottom. Samples of benthic macroinvertebrates and estuarine environmental variables were collected. Environmental drivers of the benthic macroinvertebrate community were determined by Distance-based Linear Models analysis. The contribution of individual species to the dissimilarity between the areas and substrate types were determined by analysis of the percentage of similarity. Results The composition of benthic macroinvertebrate community differed between the upper and lower areas, although it was similar between the muddy and sandy bottoms. The variation in the benthic community between areas was mainly related to the influence of salinity in the upper area. In the lower area, the variation of the macroinvertebrates was related to salinity, associated with other variables in the sandy (temperature, turbidity and dissolved oxygen and muddy (temperature, total dissolved solids and dissolved oxygen substrates. Taxa which contributed most to the dissimilarity between the upper and lower areas were Nereididae (17.89%, Anomalocardia brasiliana (15% and Cirratulidae (10.43%. Conclusions Salinity was the main driver of the structural aspects of the benthic macroinvertebrate community in the upper area of the estuary, although in the lower area a set of

  11. Tidal Channel Diatom Assemblages Reflect within Wetland Environmental Conditions and Land Use at Multiple Scales

    Science.gov (United States)

    We characterized regional patterns of the tidal channel benthic diatom community and examined the relative importance of local wetland and surrounding landscape level factors measured at multiple scales in structuring this assemblage. Surrounding land cover was characterized at ...

  12. Ichthyoplankton assemblages of coastal west-central Lake Erie and associated habitat characteristics

    Science.gov (United States)

    McKenna, J.E.; Hunter, R. Douglas; Fabrizio, M.C.; Savino, J.F.; Todd, T.N.; Bur, M.

    2008-01-01

    Early life stage survival often determines fish cohort strength and that survival is affected by habitat conditions. The structure and dynamics of ichthyoplankton assemblages can tell us much about biodiversity and fish population dynamics, but are poorly understood in nearshore areas of the Great Lakes, where most spawning and nursery habitats exist. Ichthyoplankton samples were collected with a neuston net in waters 2-13 m deep weekly or biweekly from mid-April through August, during 3 years (2000-2002) as part of a study of fish assemblages in west-central Lake Erie. A suite of abiotic variables was simultaneously measured to characterize habitat. Cluster and ordination analyses revealed several distinct ichthyoplankton assemblages that changed seasonally. A lake whitefish (Coregonus clupeaformis) dominated assemblage appeared first in April. In May, assemblages were dominated by several percid species. Summer assemblages were overwhelmingly dominated by emerald shiner (Notropis atherinoides), with large gizzard shad (Dorosoma cepedianum) and alewife (Alosa pseudoharengus) components. This seasonal trend in species assemblages was also associated with increasing temperature and water clarity. Water depth and drift processes may also play a role in structuring these assemblages. The most common and widely distributed assemblages were not associated with substratum type, which we characterized as either hard or soft. The timing of hatch and larval growth separated the major groups in time and may have adaptive significance for the members of each major assemblage. The quality and locations (with reference to lake circulation) of spawning and nursery grounds may determine larval success and affect year class strength.

  13. Patterns of Macroinvertebrate and Fish Diversity in Freshwater Sulphide Springs

    Directory of Open Access Journals (Sweden)

    Ryan Greenway

    2014-09-01

    Full Text Available Extreme environments are characterised by the presence of physicochemical stressors and provide unique study systems to address problems in evolutionary ecology research. Sulphide springs provide an example of extreme freshwater environments; because hydrogen sulphide’s adverse physiological effects induce mortality in metazoans even at micromolar concentrations. Sulphide springs occur worldwide, but while microbial communities in sulphide springs have received broad attention, little is known about macroinvertebrates and fish inhabiting these toxic environments. We reviewed qualitative occurrence records of sulphide spring faunas on a global scale and present a quantitative case study comparing diversity patterns in sulphidic and adjacent non-sulphidic habitats across replicated river drainages in Southern Mexico. While detailed studies in most regions of the world remain scarce, available data suggests that sulphide spring faunas are characterised by low species richness. Dipterans (among macroinvertebrates and cyprinodontiforms (among fishes appear to dominate the communities in these habitats. At least in fish, there is evidence for the presence of highly endemic species and populations exclusively inhabiting sulphide springs. We provide a detailed discussion of traits that might predispose certain taxonomic groups to colonize sulphide springs, how colonizers subsequently adapt to cope with sulphide toxicity, and how adaptation may be linked to speciation processes.

  14. Stream habitat structure influences macroinvertebrate response to pesticides

    International Nuclear Information System (INIS)

    Rasmussen, Jes Jessen; Wiberg-Larsen, Peter; Baattrup-Pedersen, Annette; Friberg, Nikolai; Kronvang, Brian

    2012-01-01

    Agricultural pesticides continue to impair surface water ecosystems, although there are few assessments of interactions with other modifications such as fine sediment and physical alteration for flood drainage. We, therefore, surveyed pesticide contamination and macroinvertebrates in 14 streams along a gradient of expected pesticide exposure using a paired-reach approach to differentiate effects between physically modified and less modified sites. Apparent pesticides effects on the relative abundance of SPEcies At Risk (SPEAR) were increased at sites with degraded habitats primarily due to the absence of species with specific preferences for hard substrates. Our findings highlight the importance of physical habitat degradation in the assessment and mitigation of pesticide risk in agricultural streams. - Highlights: ► %SPEAR abundance significantly decreased with increasing TU (D. magna). ► %SPEAR abundance was significantly lower when soft sediment was dominant. ► Species specific habitat preferences influenced the total effect of pesticides. ► This study has strong implications for future stream management and risk assessment. - Ecological impacts of pesticides on stream macroinvertebrates are influenced by the heterogeneity and physical structure of micro-habitats.

  15. Effects of near-bed turbulence and micro-topography on macroinvertebrate movements across contrasting gravel-bed surfaces (Invited)

    Science.gov (United States)

    Buffin-Belanger, T. K.; Rice, S. P.; Reid, I.; Lancaster, J.

    2009-12-01

    Fluvial habitats can be described from a series of physical variables but to adequately address the habitat quality it becomes necessary to develop an understanding that combines the physical variables with the behaviour of the inhabitating organisms. The hypothesis of flow refugia provide a rational that can explain the persistence of macroinvertebrate communities in gravel-bed rivers when spates occur. The movement behaviour of macroinvertebrates is a key element to the flow refugia hypothesis, but little is known about how local near-bed turbulence and bed microtopography may affect macroinvertebrate movements. We reproduced natural gravel-bed substrates with contrasting gravel bed textures in a large flume where we were able to document the movement behaviour of the cased caddisfly Potamophylax latipennis for a specific discharge. The crawling paths and drift events of animals were analysed from video recordings. Characteristics of movements differ from one substrate to another. The crawling speed is higher for the small grain-size substrates but the mean travel distance remains approximately the same between substrates. For each substrate, the animals tended to follow consistent paths across the surface. The number of drift events and mean distance drifted is higher for the small grain-size substrate. ADV measurements close to the boundary allow detailed characterisation of near-bed hydraulic variables, including : skewness coefficients, TKE, UV correlation coefficients and integral time scales from autocorrelation analysis. For these variables, the vertical patterns of turbulence parameters are similar between the substrates but the amplitude of the average values and standard errors vary significantly. The spatial distribution of this variability is considered in relation to the crawling paths. It appears that the animals tend to crawl within areas of the substrate where low flow velocities and low turbulent kinetic energies are found, while sites that

  16. Ambiguous taxa: Effects on the characterization and interpretation of invertebrate assemblages

    Science.gov (United States)

    Cuffney, T.F.; Bilger, Michael D.; Haigler, A.M.

    2007-01-01

    Damaged and immature specimens often result in macroinvertebrate data that contain ambiguous parent-child pairs (i.e., abundances associated with multiple related levels of the taxonomic hierarchy such as Baetis pluto and the associated ambiguous parent Baetis sp.). The choice of method used to resolve ambiguous parent-child pairs may have a very large effect on the characterization of invertebrate assemblages and the interpretation of responses to environmental change because very large proportions of taxa richness (73-78%) and abundance (79-91%) can be associated with ambiguous parents. To address this issue, we examined 16 variations of 4 basic methods for resolving ambiguous taxa: RPKC (remove parent, keep child), MCWP (merge child with parent), RPMC (remove parent or merge child with parent depending on their abundances), and DPAC (distribute parents among children). The choice of method strongly affected assemblage structure, assemblage characteristics (e.g., metrics), and the ability to detect responses along environmental (urbanization) gradients. All methods except MCWP produced acceptable results when used consistently within a study. However, the assemblage characteristics (e.g., values of assemblage metrics) differed widely depending on the method used, and data should not be combined unless the methods used to resolve ambiguous taxa are well documented and are known to be comparable. The suitability of the methods was evaluated and compared on the basis of 13 criteria that considered conservation of taxa richness and abundance, consistency among samples, methods, and studies, and effects on the interpretation of the data. Methods RPMC and DPAC had the highest suitability scores regardless of whether ambiguous taxa were resolved for each sample separately or for a group of samples. Method MCWP gave consistently poor results. Methods MCWP and DPAC approximate the use of family-level identifications and operational taxonomic units (OTU), respectively. Our

  17. Modeled hydrologic metrics show links between hydrology and the functional composition of stream assemblages.

    Science.gov (United States)

    Patrick, Christopher J; Yuan, Lester L

    2017-07-01

    Flow alteration is widespread in streams, but current understanding of the effects of differences in flow characteristics on stream biological communities is incomplete. We tested hypotheses about the effect of variation in hydrology on stream communities by using generalized additive models to relate watershed information to the values of different flow metrics at gauged sites. Flow models accounted for 54-80% of the spatial variation in flow metric values among gauged sites. We then used these models to predict flow metrics in 842 ungauged stream sites in the mid-Atlantic United States that were sampled for fish, macroinvertebrates, and environmental covariates. Fish and macroinvertebrate assemblages were characterized in terms of a suite of metrics that quantified aspects of community composition, diversity, and functional traits that were expected to be associated with differences in flow characteristics. We related modeled flow metrics to biological metrics in a series of stressor-response models. Our analyses identified both drying and base flow instability as explaining 30-50% of the observed variability in fish and invertebrate community composition. Variations in community composition were related to variations in the prevalence of dispersal traits in invertebrates and trophic guilds in fish. The results demonstrate that we can use statistical models to predict hydrologic conditions at bioassessment sites, which, in turn, we can use to estimate relationships between flow conditions and biological characteristics. This analysis provides an approach to quantify the effects of spatial variation in flow metrics using readily available biomonitoring data. © 2017 by the Ecological Society of America.

  18. Rising from the ashes: Changes in salmonid fish assemblages after 30 months of the Puyehue-Cordon Caulle volcanic eruption.

    Science.gov (United States)

    Lallement, Mailén; Macchi, Patricio J; Vigliano, Pablo; Juarez, Santiago; Rechencq, Magalí; Baker, Matthew; Bouwes, Nicolaas; Crowl, Todd

    2016-01-15

    Events such as volcanic eruptions may act as disturbance agents modifying the landscape spatial diversity and increasing environmental instability. On June 4, 2011 the Puyehue-Cordon Caulle volcanic complex located on Chile (2236 m.a.s.l., 40° 02' 24" S- 70° 14' 26" W) experience a rift zone eruption ejecting during the first day 950 million metric tons into the atmosphere. Due to the westerly winds predominance, ash fell differentially upon 24 million ha of Patagonia Argentinean, been thicker deposits accumulated towards the West. In order to analyze changes on stream fish assemblages we studied seven streams 8, 19 and 30 months after the eruption along the ash deposition gradient, and compare those data to pre eruption ones. Habitat features and structure of the benthic macroinvertebrate food base of fish was studied. After the eruption, substantial environmental changes were observed in association with the large amount of ash fallout. In western sites, habitat loss due to ash accumulation, changes in the riparian zone and morphology of the main channels were observed. Turbidity was the water quality variable which reflected the most changes throughout time, with NTU values decreasing sharply from West to East sites. In west sites, increased Chironomid densities were recorded 8 months after the initial eruption as well as low EPT index values. These relationships were reversed in the less affected streams farther away from the volcano. Fish assemblages were greatly influenced both by habitat and macroinvertebrate changes. The eruption brought about an initial sharp decline in fish densities and the almost total loss of young of the year in the most western streams affecting recruitment. This effect diminished rapidly with distance from the emission center. Thirty months after the eruption, environmental changes are still occurring as a consequence of basin wide ash remobilization and transport.

  19. Macroinvertebrate community response to acid mine drainage in rivers of the High Andes (Bolivia)

    International Nuclear Information System (INIS)

    Van Damme, Paul Andre; Hamel, Caroli; Ayala, Alfredo; Bervoets, Lieven

    2008-01-01

    Several High Andes Rivers are characterized by inorganic water pollution known as acid mine drainage (AMD). The aim of this study was to assess the relationship between metal concentrations in the sediments and the macroinvertebrate communities in two river basins affected by AMD. In general, the taxon diversity of the macroinvertebrate community at the family level was low. The concentrations of Cd, Cu, Zn, Pb and Ni at mining sites were higher than at unpolluted sites. The pH of the water was alkaline (7.0-8.5) in unpolluted sites, whereas it dropped to very low values (<3) at mining sites. Redundancy Analysis (RDA) showed that pH was the best predictor of macroinvertebrate community richness. The number of macroinvertebrate families decreased gradually with increasing acidity, both in pools and riffles, though it is suggested that riffle communities were more affected because they are in closer contact with the acid water. - Community response to AMD

  20. Soft sediment dwelling macro-invertebrates of Rajapur Bay, central west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Harkantra, S.N.; Parulekar, A.H.

    Thirtyfour species of soft sediment dwelling macro-invertebrates were recorded in Rajapur Bay at the proposed effluent discharge location of nuclear power plant. The fauna mainly composed of polychaetes (42.52%), molluscs (39.03%), crustaceans (7...

  1. Development of a multimetric index based on macroinvertebrates for drainage ditch networks in agricultural areas.

    NARCIS (Netherlands)

    Verdonschot, R.C.M.; Keizer-Vlek, H.E.; Verdonschot, P.F.M.

    2012-01-01

    Drainage ditches are a prominent feature of many intensively managed agricultural areas. These small, shallow, line-shaped waterbodies could harbor a rich macroinvertebrate community, resembling that of natural small lentic ecosystems. Despite their high biodiversity potential, many ditch ecosystems

  2. Numerical analyses of soft bottom macroinvertebrates to diagnose the pollution in tropical coastal waters

    Digital Repository Service at National Institute of Oceanography (India)

    Harkantra, S.N.; Rodrigues, N.R.

    of techniques to assess the impact of pollution on benthic community structure. Hence, to test this hypotheses some of the univariate and multivariate techniques were applied to soft bottom macro-invertebrates data of coastal waters of Mangalore, central west...

  3. Impact of Urban Effluents on the Macroinvertebrates of a Creek in ...

    African Journals Online (AJOL)

    User

    The impact of effluents on the macroinvertebrate communities of an urban creek in ... of complying with the Environmental Protection Agency (EPA) guidelines are ..... Business. World Water Council, Earthscan. Publications Ltd. London, UK.

  4. Individual variation in habitat use in two stream fish assemblages

    OpenAIRE

    Luisa Resende Manna; Carla Ferreira Rezende

    2015-01-01

    The habitat use is an individual choice that is influenced by physical conditions such as substrate type, food resources availability and adequate depth. However, habitat use is often measured only through interspecific variability because intraspecific variability is supposed to be low. Here, the differences in habitat use by two stream fish assemblages in two different environments (Brazilian rainforest and semiarid) were investigated at both interspecific and intraspecific levels. We perfo...

  5. The Effect of Community-Based Soil and Water Conservation Practices on Abundance and Diversity of Soil Macroinvertebrates in the Northern Highlands of Ethiopia

    Directory of Open Access Journals (Sweden)

    Mengistu Welemariam

    2018-04-01

    Full Text Available Soil and water conservation (SWC practices in the northern highlands of Ethiopia have important implications for land restoration and biodiversity recovery. The present study determined soil macroinvertebrate (SMI abundance and diversity in response to spatial conditions i.e., generated by different conservation practices, soil depth, and temporal seasonality with the wet and dry season. The SWC practices considered were exclosure + terrace, exclosure alone, terraces, and non-conserved grazing lands. Each SWC measure was selected in three sites that were considered as replications due to low heterogeneity in terms of human and livestock disturbances and biophysical factors. Soil macroinvertebrates were collected using a monolith according to tropical soil biology and fertility (TSBF method. The highest density (55% of SMI was found in exclosures followed by terraces 26%. Non-conserved communal grazing lands account for only 19% of the total. Shannon diversity index was significantly (P < 0.05 higher (1.21 in the exclosures supported with terraces and the lowest (0.9 was observed in the non-conserved communal grazing lands. Diversity was also significantly (P < 0.05 higher (1.26 in wet than dry season (0.70. The highest (41% Sorensen similarity index among SMI was found between exclosures with terraces and exclosures alone during the wet season. The lowest (20% Sorensen similarity index was found between terraces alone and exclosures with terraces in dry season. Soil macroinvertebrate abundance was higher in upper (0–10 cm than lower (10–20 and 20–30 cm soil depth. Soil macroinvertebrate abundance was positively and strongly correlated with soil moisture (R2 = 0.85 and soil organic carbon stock (R2 = 0.95. However, it was negatively (R2 = −0.71 correlated with bulk density. Generally, the abundance and diversity of SMI increased as exclosures and communal grazing lands are supported with terraces.

  6. Quantification of environment-driven changes in epiphytic macroinvertebrate communities associated to Phragmites australis

    OpenAIRE

    Miguel CAÑEDO-ARGÜELLES; Maria RIERADEVALL

    2009-01-01

    The epiphytic macroinvertebrate communities associated with the Common Reed, Phragmites australis (Cav.) Trin. ex Steudel, were examined seasonally from summer 2004 to spring 2005 in eleven coastal lagoons of the Llobregat Delta (NE Spain) following the method proposed by Kornijów & Kairesalo (1994). The aims of the study were to: 1) characterise and quantify changes in epiphytic macroinvertebrate communities along environmental gradients; 2) assess the contribution of elements of the epi...

  7. The Effects of Exurbanization on Bird and Macroinvertebrate Communities in Deciduous Forests on the Cumberland Plateau, Tennessee

    Directory of Open Access Journals (Sweden)

    Jordan M. Casey

    2009-01-01

    Full Text Available To investigate the potential causes of changes to bird communities in exurban areas, we examined the relationship between bird and macroinvertebrate communities in exurbanized forest. We randomly located sampling points across a gradient of exurbanization. We used point counts to quantify bird communities and sweep netting, soil cores, pitfalls, and frass collectors to quantify macroinvertebrates. Bird communities had higher richness and abundance in exurban areas compared to undeveloped forests, and lost some species of conservation concern but gained others. The macroinvertebrate community was slightly more abundant in exurban areas, with a slight shift in taxonomic composition. The abundance of macroinvertebrates in soil cores (but not pitfalls predicted the abundance of ground-foraging birds. The abundance of macroinvertebrates in sweep nets was not associated with the abundance of aerial insectivore birds. Exurbanization therefore appears to change bird and macroinvertebrate communities, but to a lesser extent than agricultural forest fragmentation or intensive urbanization.

  8. The impact of episodic coal mine drainage pollution on benthic macroinvertebrates in streams in the Anthracite region of Pennsylvania

    International Nuclear Information System (INIS)

    MacCausland, A.; McTammany, M.E.

    2007-01-01

    Episodic coal mine drainage, caused by fluctuations in mine discharges relative to stream flow, has devastating effects on aquatic macroinvertebrate communities. Seven stream reaches in the Anthracite region of Pennsylvania were identified as chronically, episodically or not impaired by mine drainage, and sampled seasonally for 1 year to determine the effect of episodic mine drainage on macroinvertebrates. Specific conductance fluctuated seasonally in episodic sites; it was lower in winter when discharge increased and higher in summer when discharges decreased and mine drainage made up a larger proportion of stream flow. Although we hypothesized that episodic streams would have higher macroinvertebrate richness than chronic streams, comparisons showed no differences in richness between treatments. Episodic pollution may result from undersized or poorly maintained passive treatment systems; therefore, intensive macroinvertebrate monitoring may be needed to identify streams being affected by episodic mine drainage because macroinvertebrate richness may be sensitive to water quality fluctuations. - Episodic coal mine pollution decreases benthic macroinvertebrate richness and density

  9. Louisiana waterthrush and benthic macroinvertebrate response to shale gas development

    Science.gov (United States)

    Wood, Petra; Frantz, Mack W.; Becker, Douglas A.

    2016-01-01

    Because shale gas development is occurring over large landscapes and consequently is affecting many headwater streams, an understanding of its effects on headwater-stream faunal communities is needed. We examined effects of shale gas development (well pads and associated infrastructure) on Louisiana waterthrush Parkesia motacilla and benthic macroinvertebrate communities in 12 West Virginia headwater streams in 2011. Streams were classed as impacted (n = 6) or unimpacted (n = 6) by shale gas development. We quantified waterthrush demography (nest success, clutch size, number of fledglings, territory density), a waterthrush Habitat Suitability Index, a Rapid Bioassessment Protocol habitat index, and benthic macroinvertebrate metrics including a genus-level stream-quality index for each stream. We compared each benthic metric between impacted and unimpacted streams with a Student's t-test that incorporated adjustments for normalizing data. Impacted streams had lower genus-level stream-quality index scores; lower overall and Ephemeroptera, Plecoptera, and Trichoptera richness; fewer intolerant taxa, more tolerant taxa, and greater density of 0–3-mm individuals (P ≤ 0.10). We then used Pearson correlation to relate waterthrush metrics to benthic metrics across the 12 streams. Territory density (no. of territories/km of stream) was greater on streams with higher genus-level stream-quality index scores; greater density of all taxa and Ephemeroptera, Plecoptera, and Trichoptera taxa; and greater biomass. Clutch size was greater on streams with higher genus-level stream-quality index scores. Nest survival analyses (n = 43 nests) completed with Program MARK suggested minimal influence of benthic metrics compared with nest stage and Habitat Suitability Index score. Although our study spanned only one season, our results suggest that shale gas development affected waterthrush and benthic communities in the headwater streams we studied. Thus, these ecological effects of

  10. Urbanization reduces and homogenizes trait diversity in stream macroinvertebrate communities.

    Science.gov (United States)

    Barnum, Thomas R; Weller, Donald E; Williams, Meghan

    2017-12-01

    More than one-half of the world's population lives in urban areas, so quantifying the effects of urbanization on ecological communities is important for understanding whether anthropogenic stressors homogenize communities across environmental and climatic gradients. We examined the relationship of impervious surface coverage (a marker of urbanization) and the structure of stream macroinvertebrate communities across the state of Maryland and within each of Maryland's three ecoregions: Coastal Plain, Piedmont, and Appalachian, which differ in stream geomorphology and community composition. We considered three levels of trait organization: individual traits, unique combinations of traits, and community metrics (functional richness, functional evenness, and functional divergence) and three levels of impervious surface coverage (low [10%]). The prevalence of an individual trait differed very little between low impervious surface and high impervious surface sites. The arrangement of trait combinations in community trait space for each ecoregion differed when impervious surface coverage was low, but the arrangement became more similar among ecoregions as impervious surface coverage increased. Furthermore, trait combinations that occurred only at low or medium impervious surface coverage were clustered in a subset of the community trait space, indicating that impervious surface affected the presence of only a subset of trait combinations. Functional richness declined with increasing impervious surface, providing evidence for environmental filtering. Community metrics that include abundance were also sensitive to increasing impervious surface coverage: functional divergence decreased while functional evenness increased. These changes demonstrate that increasing impervious surface coverage homogenizes the trait diversity of macroinvertebrate communities in streams, despite differences in initial community composition and stream geomorphology among ecoregions. Community

  11. Macro-invertebrate decline in surface water polluted with imidacloprid.

    Directory of Open Access Journals (Sweden)

    Tessa C Van Dijk

    Full Text Available Imidacloprid is one of the most widely used insecticides in the world. Its concentration in surface water exceeds the water quality norms in many parts of the Netherlands. Several studies have demonstrated harmful effects of this neonicotinoid to a wide range of non-target species. Therefore we expected that surface water pollution with imidacloprid would negatively impact aquatic ecosystems. Availability of extensive monitoring data on the abundance of aquatic macro-invertebrate species, and on imidacloprid concentrations in surface water in the Netherlands enabled us to test this hypothesis. Our regression analysis showed a significant negative relationship (P<0.001 between macro-invertebrate abundance and imidacloprid concentration for all species pooled. A significant negative relationship was also found for the orders Amphipoda, Basommatophora, Diptera, Ephemeroptera and Isopoda, and for several species separately. The order Odonata had a negative relationship very close to the significance threshold of 0.05 (P = 0.051. However, in accordance with previous research, a positive relationship was found for the order Actinedida. We used the monitoring field data to test whether the existing three water quality norms for imidacloprid in the Netherlands are protective in real conditions. Our data show that macrofauna abundance drops sharply between 13 and 67 ng l(-1. For aquatic ecosystem protection, two of the norms are not protective at all while the strictest norm of 13 ng l(-1 (MTR seems somewhat protective. In addition to the existing experimental evidence on the negative effects of imidacloprid on invertebrate life, our study, based on data from large-scale field monitoring during multiple years, shows that serious concern about the far-reaching consequences of the abundant use of imidacloprid for aquatic ecosystems is justified.

  12. Gradients in Catostomid assemblages along a reservoir cascade

    Science.gov (United States)

    Miranda, Leandro E.; Keretz, Kevin R.; Gilliland, Chelsea R.

    2017-01-01

    Serial impoundment of major rivers leads to alterations of natural flow dynamics and disrupts longitudinal connectivity. Catostomid fishes (suckers, family Catostomidae) are typically found in riverine or backwater habitats yet are able to persist in impounded river systems. To the detriment of conservation, there is limited information about distribution of catostomid fishes in impounded rivers. We examined the longitudinal distribution of catostomid fishes over 23 reservoirs of the Tennessee River reservoir cascade, encompassing approximately 1600 km. Our goal was to develop a basin-scale perspective to guide conservation efforts. Catostomid species composition and assemblage structure changed longitudinally along the reservoir cascade. Catostomid species biodiversity was greatest in reservoirs lower in the cascade. Assemblage composition shifted from dominance by spotted sucker Minytrema melanops and buffalos Ictiobus spp. in the lower reservoirs to carpsuckers Carpiodes spp. midway through the cascade and redhorses Moxostoma spp. in the upper reservoirs. Most species did not extend the length of the cascade, and some species were rare, found in low numbers and in few reservoirs. The observed gradients in catostomid assemblages suggest the need for basin-scale conservation measures focusing on three broad areas: (1) conservation and management of the up-lake riverine reaches of the lower reservoirs, (2) maintenance of the access to quality habitat in tributaries to the upper reservoirs and (3) reintroductions into currently unoccupied habitat within species' historic distributions

  13. Reptile assemblage response to restoration of fire-suppressed longleaf pine sandhills.

    Science.gov (United States)

    Steen, David A; Smith, Lora L; Conner, L M; Litt, Andrea R; Provencher, Louis; Hiers, J Kevin; Pokswinski, Scott; Guyer, Craig

    2013-01-01

    Measuring the effects of ecological restoration on wildlife assemblages requires study on broad temporal and spatial scales. Longleaf pine (Pinus palustris) forests are imperiled due to fire suppression and subsequent invasion by hardwood trees. We employed a landscape-scale, randomized-block design to identify how reptile assemblages initially responded to restoration treatments including removal of hardwood trees via mechanical methods (felling and girdling), application of herbicides, or prescribed burning alone. Then, we examined reptile assemblages after all sites experienced more than a decade of prescribed burning at two- to thee-year return intervals. Data were collected concurrently at reference sites chosen to represent target conditions for restoration. Reptile assemblages changed most rapidly in response to prescribed burning, but reptile assemblages at all sites, including reference sites, were generally indistinguishable by the end of the study. Thus, we suggest that prescribed burning in longleaf pine forests over long time periods is an effective strategy for restoring reptile assemblages to the reference condition. Application of herbicides or mechanical removal of hardwood trees provided no apparent benefit to reptiles beyond what was achieved by prescribed fire alone.

  14. Coral reef fish assemblages at Clipperton Atoll (Eastern Tropical Pacific and their relationship with coral cover

    Directory of Open Access Journals (Sweden)

    Aurora M. Ricart

    2016-11-01

    Full Text Available Clipperton Atoll, one of the most isolated coral reefs worldwide, is of great scientific interest due to its geomorphology and high levels of endemism. This study explored the reef fish assemblage structure of Clipperton Atoll and its relationship with live coral cover. Nine stations were sampled at three sites and three depths (6, 12 and 20 m around the reef, measuring fish species richness and biomass and hermatypic coral cover (at genus level. We evaluated variation in species richness, biomass and diversity of fish assemblages among sites and depths, as well as the relationship between the entire fish assemblage composition and live coral cover. The results showed that species richness and biomass were similar among sites, but differed across depths, increasing with depth. In contrast, diversity differed among sites but not among depths. Multivariate analyses indicated that fish assemblage composition differed among sites and depths in relation to changes in cover of coral of the genera Pocillopora, Porites, Pavona and Leptoseris, which dominate at different depths. The results showed that fish species richness and diversity were low at Clipperton Atoll and that, in isolated coral reefs with a low habitat heterogeneity and low human disturbance, live coral cover has a significant influence on the spatial variation of the reef fish assemblages. This study highlights the importance of coral habitat structure in shaping coral reef fish assemblages.

  15. Marine heatwaves and optimal temperatures for microbial assemblage activity

    OpenAIRE

    Joint, IR; Smale, DA

    2016-01-01

    The response of microbial assemblages to instantaneous temperature change was measured in a seasonal study of the coastal waters of the western English Channel. On 18 occasions between November 1999 and December 2000, bacterial abundance was assessed and temperature responses determined from the incorporation of 3H leucine, measured in a temperature gradient from 5°C to 38°C. Q10 values varied, being close to 2 in spring and summer but were >3 in autumn. There was a seasonal pattern in the as...

  16. Influence of salinity and prey presence on the survival of aquatic macroinvertebrates of a freshwater marsh

    Science.gov (United States)

    Kang, Sung-Ryong; King, Sammy L.

    2012-01-01

    Salinization of coastal freshwater environments is a global issue. Increased salinity from sea level rise, storm surges, or other mechanisms is common in coastal freshwater marshes of Louisiana, USA. The effects of salinity increases on aquatic macroinvertebrates in these systems have received little attention, despite the importance of aquatic macroinvertebrates for nutrient cycling, biodiversity, and as a food source for vertebrate species. We used microcosm experiments to evaluate the effects of salinity, duration of exposure, and prey availability on the relative survival of dominant aquatic macroinvertebrates (i.e., Procambarus clarkii Girard, Cambarellus puer Hobbs, Libellulidae, Dytiscidae cybister) in a freshwater marsh of southwestern Louisiana. We hypothesized that increased salinity, absence of prey, and increased duration of exposure would decrease survival of aquatic macroinvertebrates and that crustaceans would have higher survival than aquatic insect taxon. Our first hypothesis was only partially supported as only salinity increases combined with prolonged exposure duration affected aquatic macroinvertebrate survival. Furthermore, crustaceans had higher survival than aquatic insects. Salinity stress may cause mortality when acting together with other stressful conditions.

  17. Successional trends of the benthic macroinvertebrate community in a new southeastern cooling reservoir

    International Nuclear Information System (INIS)

    Griffin, M.A.; Herring, M.K.

    1990-01-01

    Lakes created by river impoundments provide new lentic habitats for benthic macroinvertebrates. As new lakes age, benthic macroinvertebrate succession proceeds as first colonizers are replaced and stable populations eventually become established. L Lake, a 400 ha reservoir, was constructed in 1985 on the Department of Energy's Savannah River Site in South Carolina to receive heated effluent from a nuclear production reactor. Benthic macroinvertebrates were collected in L Lake with a ponar grab sampler at 2 and 4 meters at 10 locations in 5 lake regions. Monthly collections were made from 1986 through 1989. Annual average densities of benthic macroinvertebrates increased substantially during the study (ranging from 3955.5--4471.6 organisms/m 2 in 1986 to 8948.1--11,694.1 organisms/m 2 in 1988). Annual mean biomass also increased (ranging from 0.749--0.907g AFDM/m 2 in 1986 to 2074--11,322 g AFDM/m 2 in 1988). Mean annual taxa richness ranged from 9.3--12.2 per ponar in 1986 to 11.8--15.3 per ponar in 1988. Some early colonizers (Chironomidae: Chironomini) dominated throughout the study (ranging from 60.3--79.1% of all organisms). Other chironomids (Tanytarsini and Tanypodinae) declined while slower colonizers (oligochaetes and nematodes) generally increased from 1986 through 1988. The increases in macroinvertebrate density, biomass and changes in community composition observed are typical of early reservoir succession. 14 refs., 12 figs., 1 tab

  18. In situ effects of titanium dioxide nanoparticles on community structure of freshwater benthic macroinvertebrates.

    Science.gov (United States)

    Jovanović, Boris; Milošević, Djuradj; Piperac, Milica Stojković; Savić, Ana

    2016-06-01

    For the first time in the current literature, the effect of titanium dioxide (TiO2) nanoparticles on the community structure of macroinvertebrates has been investigated in situ. Macroinvertebrates were exposed for 100 days to an environmentally relevant concentration of TiO2 nanoparticles, 25 mg kg(-1) in sediment. Czekanowski's index was 0.61, meaning 39% of the macroinvertebrate community structure was affected by the TiO2 treatment. Non-metric multidimensional scaling (NMDS) visualized the qualitative and quantitative variability of macroinvertebrates at the community level among all samples. A distance-based permutational multivariate analysis of variance (PERMANOVA) revealed the significant effect of TiO2 on the macroinvertebrate community structure. The indicator value analysis showed that the relative frequency and abundance of Planorbarius corneus and Radix labiata were significantly lower in the TiO2 treatment than in the control. Meanwhile, Ceratopogonidae, showed a significantly higher relative frequency and abundance in the TiO2 treatment than in the control. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Impact of heavy metals on macro-invertebrate fauna of the thaddo stream

    International Nuclear Information System (INIS)

    Nazneen, S.; Begum, F.; Sharmeen, R.; Ahmed, Z.

    2003-01-01

    Impact of some heavy metals like zinc, lead, copper, chromium and cadmium were studied at four spots on the macro-invertebrate fauna of the Thaddo stream, a tributary of Malir River. This was in correlation with an earlier study on the physico-chemical aspects of water which showed a severe pollution in this stream. Present data for the qualitative and quantitative analyses of macro-invertebrates and the ranges of heavy metals (Zn 0.5-3.5, Pb 0.90-1.42, Cu 0.35-0.93, Cr 0.0-0.08 and Cd 0.003-0.01 ppm) in the water samples also indicate high level of pollution in the stream. Macro-invertebrate fauna comprises only of aquatic insects which include larvae of Chironomus spp., adults of the Notonectus sp., and nymphs of Gomphus sp. (dragon fly) belonging to the order Diptera , Hemiptera and Odonata, respectively. Quantitatively Notonectus sp. predominated and followed by Chironomus larvae. The maximum concentrations of all heavy metals were recorded at spot 3. A general trend of increase was observed from up stream to down stream regions particularly in the level of zinc. However, a reverse trend was observed in the abundance of macro-invertebrates with a great reduction at spot 4. The statistical analysis of the data generally indicates a negative correlation between the values of the studied heavy metals and the abundance of macro-invertebrates throughout this study. (author)

  20. Eucalypt plantations reduce the diversity of macroinvertebrates in small forested streams

    Directory of Open Access Journals (Sweden)

    Cordero–Rivera, A.

    2017-01-01

    Full Text Available Land use patterns of a river basin have a significant effect on the structure and function of river ecosystems. Changes in the composition of riparian plant communities modify the quantity, quality and seasonality of leaf–litter inputs, determining changes in macroinvertebrate colonization and activity. The main goal of this study was to test the effect of land–use modifications, and particularly the impact of eucalypt plantations, on the macroinvertebrate communities of sixteen headwater streams. Macroinvertebrates were counted and identified to family level. Land uses were classified in five categories using aerial photography: native forest, eucalypt plantations, agricultural land, shrubland, and urban areas. We found that macroinvertebrate diversity increased with basin size and with the proportion of basin covered by native forest. This variable correlated negatively with the land occupied by eucalypt plantations. Macroinvertebrate richness diminished with the increase of land surface covered by eucalypt plantations, and a similar tendency was observed with diversity. Furthermore, streams whose drainage basin was mainly covered by Eucalyptus were more likely to dry up in summer. This observation adds to evidence from previous studies that concluded that fast–growing tree plantations affect hydric resources, an important ecosystem service in the context of global warming. To minimize the impact of industrial sylviculture, we suggest that maintaining and/or restoring riparian forests could mitigate the effects of intensive eucalypt monocultures.

  1. Scale-dependency of macroinvertebrate communities: responses to contaminated sediments within run-of-river dams.

    Science.gov (United States)

    Colas, Fanny; Archaimbault, Virginie; Devin, Simon

    2011-03-01

    Due to their nutrient recycling function and their importance in food-webs, macroinvertebrates are essential for the functioning of aquatic ecosystems. These organisms also constitute an important component of biodiversity. Sediment evaluation and monitoring is an essential aspect of ecosystem monitoring since sediments represent an important component of aquatic habitats and are also a potential source of contamination. In this study, we focused on macroinvertebrate communities within run-of-river dams, that are prime areas for sediment and pollutant accumulation. Little is known about littoral macroinvertebrate communities within run-of-river dam or their response to sediment levels and pollution. We therefore aimed to evaluate the following aspects: the functional and structural composition of macroinvertebrate communities in run-of-river dams; the impact of pollutant accumulation on such communities, and the most efficient scales and tools needed for the biomonitoring of contaminated sediments in such environments. Two run-of-river dams located in the French alpine area were selected and three spatial scales were examined: transversal (banks and channel), transversal x longitudinal (banks/channel x tail/middle/dam) and patch scale (erosion, sedimentation and vegetation habitats). At the patch scale, we noted that the heterogeneity of littoral habitats provided many available niches that allow for the development of diversified macroinvertebrate communities. This implies highly variable responses to contamination. Once combined on a global 'banks' spatial scale, littoral habitats can highlight the effects of toxic disturbances. Copyright © 2011 Elsevier B.V. All rights reserved.

  2. Short-term effects of visitor trampling on macroinvertebrates in karst streams in an ecotourism region.

    Science.gov (United States)

    Escarpinati, Suzana Cunha; Siqueira, Tadeu; Medina, Paulino Barroso; de Oliveira Roque, Fabio

    2014-03-01

    In order to evaluate the potential risks of human visitation on macroinvertebrate communities in streams, we investigated the effect of trampling using two short-term experiments conducted in a Brazilian ecotourism karst region. We asked three questions: (a) Does trampling increase the drift rate of aquatic macroinvertebrates and organic matter? (b) Does trampling change the macroinvertebrate community organization? (c) If trampling alters the community structure, is a short time (5 days, a between weekends interval - peaks of tourism activities) sufficient for community restructuring? Analysis of variance of richness, total abundance, abundance of the most abundant genus (e.g., Simothraulopsis and Callibaetis), and community composition showed that trampling immediately affects macroinvertebrate community and that the intervals between the peaks of visitation (5 days) are not sufficient to complete community restructuring. Considering that bathing areas receive thousands of visitors every year and that intervals of time without visitation are nearly nonexistent, we suspect that the negative effects on the macroinvertebrate community occur in a cumulative way. Finally, we discuss some simple procedures that could potentially be used for reducing trampling impacts in lotic environments.

  3. Rapid biotic homogenization of marine fish assemblages

    Science.gov (United States)

    Magurran, Anne E.; Dornelas, Maria; Moyes, Faye; Gotelli, Nicholas J.; McGill, Brian

    2015-01-01

    The role human activities play in reshaping biodiversity is increasingly apparent in terrestrial ecosystems. However, the responses of entire marine assemblages are not well-understood, in part, because few monitoring programs incorporate both spatial and temporal replication. Here, we analyse an exceptionally comprehensive 29-year time series of North Atlantic groundfish assemblages monitored over 5° latitude to the west of Scotland. These fish assemblages show no systematic change in species richness through time, but steady change in species composition, leading to an increase in spatial homogenization: the species identity of colder northern localities increasingly resembles that of warmer southern localities. This biotic homogenization mirrors the spatial pattern of unevenly rising ocean temperatures over the same time period suggesting that climate change is primarily responsible for the spatial homogenization we observe. In this and other ecosystems, apparent constancy in species richness may mask major changes in species composition driven by anthropogenic change. PMID:26400102

  4. Long-term patterns of chironomid assemblages in a high elevation stream/lake network (Switzerland – Implications to global change

    Directory of Open Access Journals (Sweden)

    Brigitte Lods-Crozet

    2012-10-01

    Full Text Available A long-term monitoring program was initiated in 2002 on running and standing waters in a high elevation cirque landscape (Macun in the Swiss National Park. The region comprises contrasting basins with different water sources, a glacier-fed basin and two precipitation-fed basins. Sampling of 26 permanent and temporary ponds (or small lakes and of interconnecting streams (10 sites was conducted from 2002 to 2010. Pond macroinvertebrate assemblages were dominated by chironomids with 42 taxa. The Orthocladiinae were the dominant subfamily in richness and abundance with 22 taxa. The greatest diversity was found in ponds located in the south and outlet basins. The inter-year variability for the same pond is high, but no clear temporal trend was noticed in ponds frequently monitored ponds. The Orthocladiinae subfamily was also the richest in the stream sites where 33 taxa were collected. The north and south basins were separated on the basis of chironomid assemblages. The chironomid assemblages in the stream network shows a temporal trend from 2002 but it cannot be linked to any clear change at the community structure level. The higher richness and abundance in stream sites and ponds of the south basin could be related to a greater heterogeneity in water physico-chemistry and substrata, and by the presence of Bryophyta. The understanding of the environmental factors that influence faunal assemblages is crucial for the protection of this sensitive alpine pond network where a relatively high overall regional diversity (49 taxa is detected. From the literature, temperature is recognized as the driving force on changes in chironomid assemblages in alpine systems. Our results support the use of chironomids as flagship indicators in the assessment of climatic change in alpine landscapes.doi: 10.5324/fn.v31i0.1361.Published online: 17 October 2012.

  5. Assessment of ecological quality of the Tajan river in Iran using a multimetric macroinvertebrate index and species traits

    NARCIS (Netherlands)

    Aazami, J.; Esmaili Sari, A.; Abdoli, A.; Sohrabi, H.; Brink, van den P.J.

    2015-01-01

    The objectives of this study were to assess the biological water of the Iranian Tajan River using different metrics, i.e., a Multimetric Macroinvertebrate Index (MMI) and a traits-based method. Twenty-eight physico-chemical parameters, 10 habitat factors, and abundance of macroinvertebrates were

  6. Comparison of two methods for estimating the abundance, diversity and habitat preference of fluvial macroinvertebrates in contrasting habitats

    NARCIS (Netherlands)

    Alonso, A.; Camargo, J.A.

    2010-01-01

    In this research we evaluate the effects of the method used for estimating the potential surface available for benthic macroinvertebrates in macrophyte and unvegetated habitats on several metrics and habitat preference of aquatic macroinvertebrates in the upper catchment of the Henares River

  7. Intensive removal of signal crayfish (Pacifastacus leniusculus) from rivers increases numbers and taxon richness of macroinvertebrate species.

    Science.gov (United States)

    Moorhouse, Tom P; Poole, Alison E; Evans, Laura C; Bradley, David C; Macdonald, David W

    2014-02-01

    Invasive species are a major cause of species extinction in freshwater ecosystems, and crayfish species are particularly pervasive. The invasive American signal crayfish Pacifastacus leniusculus has impacts over a range of trophic levels, but particularly on benthic aquatic macroinvertebrates. Our study examined the effect on the macroinvertebrate community of removal trapping of signal crayfish from UK rivers. Crayfish were intensively trapped and removed from two tributaries of the River Thames to test the hypothesis that lowering signal crayfish densities would result in increases in macroinvertebrate numbers and taxon richness. We removed 6181 crayfish over four sessions, resulting in crayfish densities that decreased toward the center of the removal sections. Conversely in control sections (where crayfish were trapped and returned), crayfish density increased toward the center of the section. Macroinvertebrate numbers and taxon richness were inversely correlated with crayfish densities. Multivariate analysis of the abundance of each taxon yielded similar results and indicated that crayfish removals had positive impacts on macroinvertebrate numbers and taxon richness but did not alter the composition of the wider macroinvertebrate community. Synthesis and applications: Our results demonstrate that non-eradication-oriented crayfish removal programmes may lead to increases in the total number of macroinvertebrates living in the benthos. This represents the first evidence that removing signal crayfish from riparian systems, at intensities feasible during control attempts or commercial crayfishing, may be beneficial for a range of sympatric aquatic macroinvertebrates.

  8. Microhabitat influence on larval fish assemblages within ...

    Science.gov (United States)

    We examined larval and juvenile fish assemblage structure in relation to microhabitat variables within the St. Louis River estuary, a drowned river mouth of Lake Superior. Fish were sampled in vegetated beds throughout the estuary, across a gradient of vegetation types and densities (including disturbed, preserved and post-restoration sites). Canonical correspondence analysis, relating species abundances to environmental variables revealed that plant species richness, turbidity and aquatic plant cover were most influential in structuring assemblages. Results from this microhabitat analysis at this crucial life stage has potential to inform wetland restoration efforts within the St. Louis River and other Great Lake coastal wetlands. not applicable

  9. A Multimetric Benthic Macroinvertebrate Index for the Assessment of Stream Biotic Integrity in Korea

    Directory of Open Access Journals (Sweden)

    Soon-Jin Hwang

    2012-10-01

    Full Text Available At a time when anthropogenic activities are increasingly disturbing the overall ecological integrity of freshwater ecosystems, monitoring of biological communities is central to assessing the health and function of streams. This study aimed to use a large nation-wide database to develop a multimetric index (the Korean Benthic macroinvertebrate Index of Biological Integrity—KB-IBI applicable to the biological assessment of Korean streams. Reference and impaired conditions were determined based on watershed, chemical and physical criteria. Eight of an initial 34 candidate metrics were selected using a stepwise procedure that evaluated metric variability, redundancy, sensitivity and responsiveness to environmental gradients. The selected metrics were number of taxa, percent Ephemeroptera-Plecoptera-Trichoptera (EPT individuals, percent of a dominant taxon, percent taxa abundance without Chironomidae, Shannon’s diversity index, percent gatherer individuals, ratio of filterers and scrapers, and the Korean saprobic index. Our multimetric index successfully distinguished reference from impaired conditions. A scoring system was established for each core metric using its quartile range and response to anthropogenic disturbances. The multimetric index was classified by aggregating the individual metric ..scores and the value range was quadrisected to provide a narrative criterion (Poor, Fair, Good and Excellent to describe the biological integrity of the streams in the study. A validation procedure showed that the index is an effective method for evaluating stream conditions, and thus is appropriate for use in future studies measuring the long-term status of streams, and the effectiveness of restoration methods.

  10. A Multimetric Benthic Macroinvertebrate Index for the Assessment of Stream Biotic Integrity in Korea

    Science.gov (United States)

    Jun, Yung-Chul; Won, Doo-Hee; Lee, Soo-Hyung; Kong, Dong-Soo; Hwang, Soon-Jin

    2012-01-01

    At a time when anthropogenic activities are increasingly disturbing the overall ecological integrity of freshwater ecosystems, monitoring of biological communities is central to assessing the health and function of streams. This study aimed to use a large nation-wide database to develop a multimetric index (the Korean Benthic macroinvertebrate Index of Biological Integrity—KB-IBI) applicable to the biological assessment of Korean streams. Reference and impaired conditions were determined based on watershed, chemical and physical criteria. Eight of an initial 34 candidate metrics were selected using a stepwise procedure that evaluated metric variability, redundancy, sensitivity and responsiveness to environmental gradients. The selected metrics were number of taxa, percent Ephemeroptera-Plecoptera-Trichoptera (EPT) individuals, percent of a dominant taxon, percent taxa abundance without Chironomidae, Shannon’s diversity index, percent gatherer individuals, ratio of filterers and scrapers, and the Korean saprobic index. Our multimetric index successfully distinguished reference from impaired conditions. A scoring system was established for each core metric using its quartile range and response to anthropogenic disturbances. The multimetric index was classified by aggregating the individual metric ..scores and the value range was quadrisected to provide a narrative criterion (Poor, Fair, Good and Excellent) to describe the biological integrity of the streams in the study. A validation procedure showed that the index is an effective method for evaluating stream conditions, and thus is appropriate for use in future studies measuring the long-term status of streams, and the effectiveness of restoration methods. PMID:23202765

  11. Aquatic macroinvertebrate responses to native and non-native predators

    Directory of Open Access Journals (Sweden)

    Haddaway N. R.

    2014-01-01

    Full Text Available Non-native species can profoundly affect native ecosystems through trophic interactions with native species. Native prey may respond differently to non-native versus native predators since they lack prior experience. Here we investigate antipredator responses of two common freshwater macroinvertebrates, Gammarus pulex and Potamopyrgus jenkinsi, to olfactory cues from three predators; sympatric native fish (Gasterosteus aculeatus, sympatric native crayfish (Austropotamobius pallipes, and novel invasive crayfish (Pacifastacus leniusculus. G. pulex responded differently to fish and crayfish; showing enhanced locomotion in response to fish, but a preference for the dark over the light in response to the crayfish. P.jenkinsi showed increased vertical migration in response to all three predator cues relative to controls. These different responses to fish and crayfish are hypothesised to reflect the predators’ differing predation types; benthic for crayfish and pelagic for fish. However, we found no difference in response to native versus invasive crayfish, indicating that prey naiveté is unlikely to drive the impacts of invasive crayfish. The Predator Recognition Continuum Hypothesis proposes that benefits of generalisable predator recognition outweigh costs when predators are diverse. Generalised responses of prey as observed here will be adaptive in the presence of an invader, and may reduce novel predators’ potential impacts.

  12. Marine sediment sample pre-processing for macroinvertebrates metabarcoding: mechanical enrichment and homogenization

    Directory of Open Access Journals (Sweden)

    Eva Aylagas

    2016-10-01

    Full Text Available Metabarcoding is an accurate and cost-effective technique that allows for simultaneous taxonomic identification of multiple environmental samples. Application of this technique to marine benthic macroinvertebrate biodiversity assessment for biomonitoring purposes requires standardization of laboratory and data analysis procedures. In this context, protocols for creation and sequencing of amplicon libraries and their related bioinformatics analysis have been recently published. However, a standardized protocol describing all previous steps (i.e. processing and manipulation of environmental samples for macroinvertebrate community characterization is lacking. Here, we provide detailed procedures for benthic environmental sample collection, processing, enrichment for macroinvertebrates, homogenization, and subsequent DNA extraction for metabarcoding analysis. Since this is the first protocol of this kind, it should be of use to any researcher in this field, having the potential for improvement.

  13. Functional changes in littoral macroinvertebrate communities in response to watershed-level anthropogenic stress.

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    Katya E Kovalenko

    Full Text Available Watershed-scale anthropogenic stressors have profound effects on aquatic communities. Although several functional traits of stream macroinvertebrates change predictably in response to land development and urbanization, little is known about macroinvertebrate functional responses in lakes. We assessed functional community structure, functional diversity (Rao's quadratic entropy and voltinism in macroinvertebrate communities sampled across the full gradient of anthropogenic stress in Laurentian Great Lakes coastal wetlands. Functional diversity and voltinism significantly decreased with increasing development, whereas agriculture had smaller or non-significant effects. Functional community structure was affected by watershed-scale development, as demonstrated by an ordination analysis followed by regression. Because functional community structure affects energy flow and ecosystem function, and functional diversity is known to have important implications for ecosystem resilience to further environmental change, these results highlight the necessity of finding ways to remediate or at least ameliorate these effects.

  14. Benthic Macroinvertebrate Communities in the Northern Tributaries of the “Iron Gates” Gorge (Danube River

    Directory of Open Access Journals (Sweden)

    Curtean-Bănăduc Angela

    2014-12-01

    Full Text Available The paper presents the structure of the benthonic macro-invertebrates communities in the Berzasca, Sirinia, Liubcova, and Mraconia rivers. The results are based on quantitative benthos samples (95 samples, collected in July 2014 from 19 sampling stations within the study area. In longitudinal profile, the benthonic macro-invertebrate communities of the Sirinia, Liubcova and Berzasca rivers displays relatively large structural variability, while the communities of the Mraconia River displays smaller structural variability. The structure of the benthonic macro-invertebrate communities correlated with the biotope characteristics indicates the good ecological status of the analysed rivers, with the exception of the Berzasca River sector downstream of the town of Berzasca and immediately upstream of the Danube junction, a sector with moderate ecological status due to negative effects from man-made modifications in the lotic biotope of the sector.

  15. Evaluating macroinvertebrate community shifts in the confluence of freestone and limestone streams

    Directory of Open Access Journals (Sweden)

    Jennifer K. Hellmann

    2014-07-01

    Full Text Available Aquatic macroinvertebrates are critical to ecosystem functioning through their regulation of many essential top-down and bottom-up ecosystem processes such as energy translocation, nutrient flow, and detrital decomposition. However, specific preferences by macroinvertebrates for certain ranges of abiotic and biotic characteristics mean that changes in these factors often create large differences in benthic community structure. Investigations into drivers of community structure have found distinct patterns of variation between ecosystems, but drivers of macroscale variation may differ from drivers of microscale variation. Such microscale variation in macroinvertebrate community structure as a function of abiotic conditions may be found in the confluence of two geologically distinct freshwater streams. Variation in the origin, underlying bedrock, and watershed of a stream results in drastically different physical and chemical characteristics and correspondingly distinct macroinvertebrate community structures. In areas where water from geologically distinct streams flows together, a mixing zone emerges with unique chemical and physical characteristics. There is little information on how invertebrate communities are structured within this mixing zone. To investigate this, we examined how the structure of the macroinvertebrate community changed downstream of the confluence. Up to thirty metres downstream, we found distinct stream sections that mirrored physical and chemical conditions found in limestone and freestone streams, and a mixing zone with emergent properties. These physical and chemical changes between sites were accompanied by shifts in macroinvertebrate community composition. Diversity indices indicated significantly higher diversity in freestone sites than in limestone sites or the mixing zone and there was a unique composition of genera in the mixing zone that were distinct from both limestone and freestone sites. Factors driving

  16. Benthic assemblages of mega epifauna on the Oregon continental margin

    Science.gov (United States)

    Hemery, Lenaïg G.; Henkel, Sarah K.; Cochrane, Guy R.

    2018-01-01

    Environmental assessment studies are usually required by a country's administration before issuing permits for any industrial activities. One of the goals of such environmental assessment studies is to highlight species assemblages and habitat composition that could make the targeted area unique. A section of the Oregon continental slope that had not been previously explored was targeted for the deployment of floating wind turbines. We carried out an underwater video survey, using a towed camera sled, to describe its benthic assemblages. Organisms were identified to the lowest taxonomic level possible and assemblages described related to the nature of the seafloor and the depth. We highlighted six invertebrate assemblages and three fish assemblages. For the invertebrates within flat soft sediments areas we defined three different assemblages based on primarily depth: a broad mid-depth (98–315 m) assemblage dominated by red octopus, sea pens and pink shrimps; a narrower mid-depth (250–270 m) assemblage dominated by box crabs and various other invertebrates; and a deeper (310–600 m) assemblage dominated by sea urchins, sea anemones, various snails and zoroasterid sea stars. The invertebrates on mixed sediments also were divided into three different assemblages: a shallow (~100 m deep) assemblage dominated by plumose sea anemones, broad mid-depth (170–370 m) assemblage dominated by sea cucumbers and various other invertebrates; and, again, a narrower mid-depth (230–270 m) assemblage, dominated by crinoids and encrusting invertebrates. For the fish, we identified a rockfish assemblage on coarse mixed sediments at 170–370 m and another fish assemblage on smaller mixed sediments within that depth range (250–370 m) dominated by thornyheads, poachers and flatfishes; and we identified a wide depth-range (98–600 m) fish assemblage on flat soft sediments dominated by flatfishes, eelpouts and thornyheads. Three of these assemblages (the two

  17. Benthic assemblages of mega epifauna on the Oregon continental margin

    Science.gov (United States)

    Hemery, Lenaïg G.; Henkel, Sarah K.; Cochrane, Guy R.

    2018-05-01

    Environmental assessment studies are usually required by a country's administration before issuing permits for any industrial activities. One of the goals of such environmental assessment studies is to highlight species assemblages and habitat composition that could make the targeted area unique. A section of the Oregon continental slope that had not been previously explored was targeted for the deployment of floating wind turbines. We carried out an underwater video survey, using a towed camera sled, to describe its benthic assemblages. Organisms were identified to the lowest taxonomic level possible and assemblages described related to the nature of the seafloor and the depth. We highlighted six invertebrate assemblages and three fish assemblages. For the invertebrates within flat soft sediments areas we defined three different assemblages based on primarily depth: a broad mid-depth (98-315 m) assemblage dominated by red octopus, sea pens and pink shrimps; a narrower mid-depth (250-270 m) assemblage dominated by box crabs and various other invertebrates; and a deeper (310-600 m) assemblage dominated by sea urchins, sea anemones, various snails and zoroasterid sea stars. The invertebrates on mixed sediments also were divided into three different assemblages: a shallow ( 100 m deep) assemblage dominated by plumose sea anemones, broad mid-depth (170-370 m) assemblage dominated by sea cucumbers and various other invertebrates; and, again, a narrower mid-depth (230-270 m) assemblage, dominated by crinoids and encrusting invertebrates. For the fish, we identified a rockfish assemblage on coarse mixed sediments at 170-370 m and another fish assemblage on smaller mixed sediments within that depth range (250-370 m) dominated by thornyheads, poachers and flatfishes; and we identified a wide depth-range (98-600 m) fish assemblage on flat soft sediments dominated by flatfishes, eelpouts and thornyheads. Three of these assemblages (the two broad fish assemblages and the deep

  18. Impact of pesticides on hyphomycetes leaf processing and macroinvertebrate shredding activity

    DEFF Research Database (Denmark)

    Juul Monberg, Rikke; Rasmussen, Jes; Baatrup-Pedersen, Annette

    , consequently impacting stream dwelling organism feeding on the organic material. The impact of pyrethroid insecticides on stream macroinvertebrates are well studied and increased mortality and drift rate along with decreased feeding activity are well known responses to even very low concentrations (10-100 ng...... organisms have the power to reduce organic matter breakdown and food quality for macroinvertebrates, thereby decreasing ecosystem decomposition rates. We exposed preconditioned leafs of beech (Fagus sylvatica) to the fungicide propiconazole (100, 1000 or 2000 μg/L) and/or the insecticide alpha...

  19. Megabenthic assemblages in the continental shelf edge and upper slope of the Menorca Channel, Western Mediterranean Sea

    Science.gov (United States)

    Grinyó, Jordi; Gori, Andrea; Greenacre, Michael; Requena, Susana; Canepa, Antonio; Lo Iacono, Claudio; Ambroso, Stefano; Purroy, Ariadna; Gili, Josep-Maria

    2018-03-01

    Highly diverse megabenthic assemblages dominated by passive and active suspension feeders have been recently reported in shelf edge environments of the Mediterranean Sea. Due to their frequent association with species of commercial interest, these assemblages have been heavily impacted by fishing. The vulnerability and low resilience of these assemblages, composed mainly by long-living and slow-growing species, have motivated the implementation of management measures such as the restriction of bottom trawling, and the establishment of large protected areas embracing these environments. The Menorca Channel is one of such areas recently included in the European Union Natura 2000 network. Quantitative analysis of video transects recorded at 95-360 m depth by manned submersible and remotely operated vehicles were used to characterize megabenthic assemblages and to assess their geographical and bathymetric distribution. Six different assemblages were identified, mainly segregated by substrate type and depth. Hard substrates hosted coral gardens and sponge grounds, whereas soft sediments were mainly characterized by large extensions of the crinoid Leptometra phalangium and the brachiopod Gryphus vitreus. The good preservation of most of the observed assemblages is probably related to a low bottom trawling pressure, which mainly concentrates deeper on the adjacent continental slope. Because of their biological and ecological value, management and conservation measures need to be established to preserve these benthic assemblages.

  20. Mangrove macrobenthos: Assemblages, services, and linkages

    Science.gov (United States)

    Lee, S. Y.

    2008-02-01

    Macrobenthic assemblages are relatively poorly known compared to other components of the mangrove ecosystem. Tropical mangroves support macrobenthic biodiversity resources yet to be properly documented and interpreted. Some methodological challenges, such as the generally high spatial heterogeneity and complexity of the habitat, evidently reduce sampling efficiency and accuracy, while also leaving some microhabitats under-sampled. Macrobenthic assemblage structure seems to be influenced by local environmental conditions, such as hydroperiod, organic matter availability and sediment characteristics. Brachyurans, gastropods and oligochaetes dominate in the sediment, with the former two groups also common on hard surfaces provided by tree trunks, while insects and arachnids inhabit the canopy. Traditionally, studies of mangrove macrobenthos have focused on assemblage structure or the biology of individual species, but more complex inter-specific interactions and the inter-relationship between habitat and the biota are recently being addressed. Brachyuran crabs are the best-studied macrobenthos group, but many issues about their role in mangrove ecosystem dynamics are still controversial. Despite many species of mangrove macrobenthos being referred to as 'trophic dead ends', most serve as important links between recalcitrant mangrove organic matter and estuarine secondary production, through feeding excursion by mobile nekton during the high tide, and macrobenthos-mediated processing and exportation of organic matter. A significant difference in the standing crop biomass of forests between the Indo-west-Pacific (IWP)' and Atlantic-east-Pacific (AEP) mangroves may be related to the difference in species richness of mangrove as well as macrobenthos diversity in the two bioregions. Such differences in assemblage structure may also result in different ecosystem functioning, but the nature of the links is, however, yet to be explored. There is also a strong need for

  1. Macro-Invertebrate Decline in Surface Water Polluted with Imidacloprid

    Science.gov (United States)

    Van Dijk, Tessa C.; Van Staalduinen, Marja A.; Van der Sluijs, Jeroen P.

    2013-01-01

    Imidacloprid is one of the most widely used insecticides in the world. Its concentration in surface water exceeds the water quality norms in many parts of the Netherlands. Several studies have demonstrated harmful effects of this neonicotinoid to a wide range of non-target species. Therefore we expected that surface water pollution with imidacloprid would negatively impact aquatic ecosystems. Availability of extensive monitoring data on the abundance of aquatic macro-invertebrate species, and on imidacloprid concentrations in surface water in the Netherlands enabled us to test this hypothesis. Our regression analysis showed a significant negative relationship (Pmacro-invertebrate abundance and imidacloprid concentration for all species pooled. A significant negative relationship was also found for the orders Amphipoda, Basommatophora, Diptera, Ephemeroptera and Isopoda, and for several species separately. The order Odonata had a negative relationship very close to the significance threshold of 0.05 (P = 0.051). However, in accordance with previous research, a positive relationship was found for the order Actinedida. We used the monitoring field data to test whether the existing three water quality norms for imidacloprid in the Netherlands are protective in real conditions. Our data show that macrofauna abundance drops sharply between 13 and 67 ng l−1. For aquatic ecosystem protection, two of the norms are not protective at all while the strictest norm of 13 ng l−1 (MTR) seems somewhat protective. In addition to the existing experimental evidence on the negative effects of imidacloprid on invertebrate life, our study, based on data from large-scale field monitoring during multiple years, shows that serious concern about the far-reaching consequences of the abundant use of imidacloprid for aquatic ecosystems is justified. PMID:23650513

  2. Pesticides in agricultural headwater streams in southwestern Germany and effects on macroinvertebrate populations.

    Science.gov (United States)

    Weber, Gero; Christmann, Nicole; Thiery, Ann-Cathrin; Martens, Dieter; Kubiniok, Jochen

    2018-04-01

    Pesticides are a major burden for stream ecosystems in the central European cultivated landscape. The objective of the present study was to investigate the applicability of ecological indicator methods in relation to toxicity of pesticides under the specific hydro-morphological conditions in small water bodies. Thus, an association of toxicity evaluating methods with different ecological indicators was to be attempted. Based on three random samples taken within the 2016 vegetation period, 23 headwater areas in the Saarland were investigated to test for pesticides and their metabolites. The macroinvertebrate population was also surveyed in 16 of these streams. Evidence was found of 41 substances in total. Most dominant substances include atrazine, isoproturone, quinmerac and tebuconazol as well as metabolites of dimethenamid, chloridazon and metazachlor. At 9 of the 23 sampling points, over 10 plant protection products and metabolites were found. Only 17% of the water bodies investigated contained fewer than 5 substances. Around half of the bodies of water investigated show noticeably high concentrations of metabolites of plant protection products. Maximum concentrations exceeding environmental quality standards or the Health-oriented Guideline Values were measured for 13 substances at individual sampling points. Analysis of the biological data for only 4 of the water bodies investigated resulted in the Ecological Status Class (ESC) "good". All others fell short of the quality target, although they were classified as "good" or "very good" according to the Saprobic index. SPEAR pesticides as a measurement of the sensitivity of the biocoenosis to pesticides shows their influence in a few water bodies. Likewise, high toxic unit values have also been calculated, indicating the presence of toxic substances at relevant concentrations. However, an actual correlation between SPEAR pesticides and toxic unit could not be derived. Clearly in these very headwater streams other

  3. Macroinvertebrate Community responses to gravel addition in a Southeastern regulated river

    Science.gov (United States)

    Ryan A. McManamay; Donald J. Orth; A. Charles. Dolloff

    2013-01-01

    Sediment transport, one of the key processes of river systems, is altered or stopped by dams, leaving lower river reaches barren of sand and gravel, both of which are essential habitat for fish and macroinvertebrates. One way to compensate for losses in sediment is to supplement gravel to river reaches below impoundments. Because gravel addition has become a widespread...

  4. An historical and geographic data set on the distribution of macroinvertebrates in Italian mountain lakes

    Directory of Open Access Journals (Sweden)

    Angela Boggero

    2017-11-01

    Full Text Available Macroinvertebrates play a key role in freshwater food webs, acting as major links between organic matter resources, primary consumers (such as bacteria, and secondary consumers (e.g.fish, amphibians, birds, and reptiles. In this paper we present a data set encompassing all geographic and historical data available on macroinvertebrates of the Italian mountain lakes from 1902 to 2016. The data set, divided per Italian mountain range (Alps and Apennines and administrative region, covers more than a century of studies of many foreign and Italian scientists. The data set includes 2372 records and shows macroinvertebrate occurrence data in 176 Alpine and in 13 Apennine lakes, of which 178 of natural origin, 5 reservoirs, and 6 artificially extended. The data set lists 605 taxa, updated on the basis of their current taxonomic position. Only 353 taxa are identified at species level, highlighting the still poorly investigated biodiversity of Italian mountain lake macroinvertebrates. Since they function as key elements to characterize lake ecological status, our data set emphasizes the huge taxonomic effort that still has to be undertaken to fully characterize these ecosystems. The data set is available in csv (comma-separated values format.

  5. Short-term disturbance effects of outdoor education stream classes on aquatic macroinvertebrates

    Science.gov (United States)

    Outdoor education stream classes provide students with an opportunity to gain hands-on experience with sampling methods for evaluating stream water quality. Student trampling as a result of stream classes may disrupt the substrate and negatively impact aquatic macroinvertebrates. The impact of stude...

  6. Comparison of the abiotic preferences of macroinvertebrates in tropical river basins.

    Directory of Open Access Journals (Sweden)

    Gert Everaert

    Full Text Available We assessed and compared abiotic preferences of aquatic macroinvertebrates in three river basins located in Ecuador, Ethiopia and Vietnam. Upon using logistic regression models we analyzed the relationship between the probability of occurrence of five macroinvertebrate families, ranging from pollution tolerant to pollution sensitive, (Chironomidae, Baetidae, Hydroptilidae, Libellulidae and Leptophlebiidae and physical-chemical water quality conditions. Within the investigated physical-chemical ranges, nine out of twenty-five interaction effects were significant. Our analyses suggested river basin dependent associations between the macroinvertebrate families and the corresponding physical-chemical conditions. It was found that pollution tolerant families showed no clear abiotic preference and occurred at most sampling locations, i.e. Chironomidae were present in 91%, 84% and 93% of the samples taken in Ecuador, Ethiopia and Vietnam. Pollution sensitive families were strongly associated with dissolved oxygen and stream velocity, e.g. Leptophlebiidae were only present in 48%, 2% and 18% of the samples in Ecuador, Ethiopia and Vietnam. Despite some limitations in the study design, we concluded that associations between macroinvertebrates and abiotic conditions can be river basin-specific and hence are not automatically transferable across river basins in the tropics.

  7. Metal contamination in benthic macroinvertebrates in a sub-basin in the southeast of Brazil

    Directory of Open Access Journals (Sweden)

    WAC Chiba

    Full Text Available Benthic macroinvertebrates have many useful properties that make possible the use of these organisms as sentinel in biomonitoring programmes in freshwater. Combined with the characteristics of the water and sediment, benthic macroinvertebrates are potential indicators of environmental quality. Thus, the spatial occurrence of potentially toxic metals (Al, Zn, Cr, Co, Cu, Fe, Mn and Ni in the water, sediment and benthic macroinvertebrates samples were investigated in a sub-basin in the southeast of Brazil in the city of São Carlos, São Paulo state, with the aim of verifying the metals and environment interaction with benthic communities regarding bioaccumulation. Hypothetically, there can be contamination by metals in the aquatic environment in the city due to lack of industrial effluent treatment. All samples were analysed by the USEPA adapted method and processed in an atomic absorption spectrophotometer. The sub-basin studied is contaminated by toxic metals in superficial water, sediment and benthic macroinvertebrates. The Bioaccumulation Factor showed a tendency for metal bioaccumulation by the benthic organisms for almost all the metal species. The results show a potential human and ecosystem health risk, contributing to metal contamination studies in aquatic environments in urban areas.

  8. Colonization by benthic macroinvertebrates in two artificial substrate types of a Riparian Forest

    Directory of Open Access Journals (Sweden)

    Lívia Borges dos Santos

    Full Text Available Abstract: Aim To analyze the efficiency of organic and inorganic substrates in samples of benthic macroinvertebrates of riparian forests from the Cerrado. Specific objectives (i characterize the ecological succession and taxonomic richness of benthic macroinvertebrates in stream affluent of a riparian forest; (ii analyze the influence of seasonality on the colonization of macroinvertebrates; and (iii determine the effect of the types of artificial substrates on the richness, composition and abundance of the benthic community. Methods Sampling was carried out in the rainy and dry seasons, and we installed in the watercourse two types of substrates: organic (leaf packs and inorganic (bricks, organized in pairs. Six samples per season were done to verify colonization, succession, richness and abundance of benthic community. The substrates were carefully sorted and the organisms were identified to the lowest possible taxonomic level. Results The ecological succession was clearly observed, with the initial occurrence of Chironomidae and Baetidae (considered early colonizers, and a late occurrence of organisms such as Helotrephidae and Trichoptera (considered late colonizers. No significant difference was found in the richness and abundance among the studied seasons (rainy and dry, but the organic substrate was significantly higher than the inorganic substrate for these parameters. Conclusion Organic artificial substrates are more efficient in characterizing the community of benthic macroinvertebrates in the study area, because they are more similar to the conditions of the substrate found naturally in the environment.

  9. Assessing Ecosystem Integrity And Macroinvertebrates Community Structure Towards Conservation Of Small Streams In Tanzania

    Directory of Open Access Journals (Sweden)

    Fredrick Ojija

    2017-02-01

    Full Text Available This study attempts to use biological indices such as Biological Monitoring Working Party BMWP Average Score Per Taxa ASPT and Hilsenhoff Family Biotic Index FBI in order to determine the ecosystem health and water quality of Nzovwe stream in Mbeya Tanzania. Macroinvertebrates were sampled from Nzovwe stream using semi-quantitative techniques from March to June 2016. About 500 meters of Nzovwe stream was divided into 5 sampling sites each site was 100 meters apart. The macroinvertebrates were collected from all the possible microhabitats of each site using a 250m mesh size D- frame kick net. Macroinvertebrate specimens were preserved in the 70 ethyl alcohol in the polyethylene bottles. The samples were identified to the family level using standard identification keys. The BMWP score and ASPT score indicated good and moderate stream water quality respectively. The FBI showed the stream had possibility of some organic pollution. The Shannon-Wiener diversity index shows the sampling sites were moderately polluted or possibly impaired. Macroinvertebrates in pollution class II were abundant suggesting moderate pollution. Moreover the Midge Insects Diptera and Snail indicated the stream water quality or ecosystem health is between unimpaired and possibly impaired. Based on these results the study concludes that the stream ecosystem is moderately polluted and therefore the study recommends a regular stream monitoring.

  10. Macroinvertebrate community response to acid mine drainage in rivers of the High Andes (Bolivia).

    NARCIS (Netherlands)

    Damme, P.A. van; Hamel, C.; Ayala, A.; Bervoets, L.

    2008-01-01

    Several High Andes Rivers are characterized by inorganic water pollution known as acid mine drainage (AMD). The aim of this study was to assess the relationship between metal concentrations in the sediments and the macroinvertebrate communities in two river basins affected by AMD. In general, the

  11. Legacy of a Chemical Factory Site: Contaminated Groundwater Impacts Stream Macroinvertebrates

    DEFF Research Database (Denmark)

    Rasmussen, Jes J.; McKnight, Ursula S.; Sonne, Anne Thobo

    2016-01-01

    data for many of the compounds occurring at contaminated sites. We studied the potential impact of a contaminated site, characterised by chlorinated solvents, sulfonamides, and barbiturates, on benthic macroinvertebrates in a receiving stream. Most of these compounds are characterised by low or unknown...

  12. Does diet influence consumer nutrient cycling? Macroinvertebrate and fish excretion in streams

    Science.gov (United States)

    Ryan McManamay; Jackson Webster; H. Valett; C. Dolloff

    2011-01-01

    Consumer nutrient cycling supplies limiting elements to autotrophic and heterotrophic organisms in aquatic systems. However, the role of consumers in supplying nutrients may change depending on their diet and their own stoichiometry. We evaluated the stoichiometry, N and P excretion, and diets of the dominant macroinvertebrates and fish at 6 stream sites to determine...

  13. Macro-Invertebrate Decline in Surface Water Polluted with Imidacloprid : A Rebuttal and Some New Analyses

    NARCIS (Netherlands)

    Vijver, M.G.; Brink, van den P.J.

    2014-01-01

    Imidacloprid, the largest selling insecticide in the world, has received particular attention from scientists, policymakers and industries due to its potential toxicity to bees and aquatic organisms. The decline of aquatic macro-invertebrates due to imidacloprid concentrations in the Dutch surface

  14. Macro-Invertebrate Decline in surface water polluted with Imidacloprid: A rebuttal and soome new analyses

    NARCIS (Netherlands)

    Vijver, M.G.; Brink, van den P.J.

    2014-01-01

    Imidacloprid, the largest selling insecticide in the world, has received particular attention from scientists, policymakers and industries due to its potential toxicity to bees and aquatic organisms. The decline of aquatic macro-invertebrates due to imidacloprid concentrations in the Dutch surface

  15. Intertidal benthic community ecology of sand-dwelling macroinvertebrates of Goa beaches

    Digital Repository Service at National Institute of Oceanography (India)

    Harkantra, S.N.; Parulekar, A.H.

    Studies on the intertidal ecology of two sandy beaches of Goa along the western coast of India revealed the presence of 47 species of macroinvertebrates belonging to 32 families. The open beach at Candolim, characterized by coarse sand-grain size...

  16. Multiple stress response of lowland stream benthic macroinvertebrates is dependent on habitat type

    DEFF Research Database (Denmark)

    Graeber, Daniel; Jensen, Tinna M.; Rasmussen, Jes

    2017-01-01

    Worldwide, lowland stream ecosystems are exposed to multiple anthropogenic stress due to the combination of water scarcity, eutrophication and fine sedimentation. The understanding of the effects of such multiple stress on stream benthic macroinvertebrates has been growing in the recent years...

  17. Contribution of trace metals in structuring in situ macroinvertebrate community composition along a salinity gradient

    NARCIS (Netherlands)

    Peeters, E.T.H.M.; Gardeniers, J.J.P.; Koelmans, A.A.

    2000-01-01

    Macroinvertebrates were studied along a salinity gradient in the North Sea Canal, The Netherlands, to quantify the effect of trace metals (cadmium, copper, lead, zinc) on community composition. In addition, two methods for assessing metal bioavailability (normalizing metal concentrations on organic

  18. Biodiversity of benthic macroinvertebrates in Air Terjun Asahan, Asahan, Melaka, Malaysia

    Science.gov (United States)

    Nurhafizah-Azwa, S.; Ahmad A., K.

    2016-11-01

    A study on benthic macroinvertebrate diversity was conducted at Air Terjun Asahan, Asahan, Melaka. Five stations were selected with distance intervals of approximately 500 metres. Three replicates of benthic macroinvertebrate and water samples were taken. Results classified Air Terjun Asahan in class II, which indicated good water quality based on WQI recommended by the Department of Environment. A total of 1 phylum, 2 classes, 6 order, 30 families, and 2183 individuals were successfully sampled and recorded. The analysis showed that the average value of Shannon Diversity Index, H' (2.19), Pielou Evenness Index, J' (0.30), and Margaleff Richness Index, DMG (3.77) described that Air Terjun Asahan was in moderate condition and the distribution of macroinvertebrates was uniform between stations. Correlation test showed that the WQI had a strong relationship with the diversity indices involved. BMWP, and FBI showed that Air Terjun Asahan was in good water quality. CCA test was conducted to show environmental factors towards benthic macroinvertebrate distribution. The presence of Leptophlebiidae, Baetidae, Heptageniidae and Chironomidae with high abundance of the families showed the potential as biological indicators of a clean ecosystem.

  19. Effects of Ecohydraulic Bank Stabilization Structures on Bank Stability and Macroinvertebrate Community in Surabaya River

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    Daru Setyo Rini

    2018-01-01

    Full Text Available There were 18 accelerated erosion sites identified along 7 km of Surabaya River Fishery Sanctuary Area. A model of ecohydraulic bank stabilization was applied to reduce bank erosion in Surabaya River at Gresik Regency Indonesia. The model is combination of reprofiled and revegetated bank with rock toe reinforcement and  addition of log groynes. Various native plant species were planted and naturally grown to establish multi-strata littoral vegetation structure. This study assessed effects of ecohydraulic bank stabilization on bank morphology, near bank velocity and littoral macroinvertebrate community during September 2014 to August 2016. The study found that rock toe enforcement, log groynes and reprofiled bank slope could stabilized the eroded bank, and littoral vegetation formation reduced near bank velocity at restored sites. There were 31 families of macroinvertebrate found in Surabaya River with high abundance of moderately pollution sensitive taxa Atyidae and pollution tolerant taxa Corixidae, Chironomidae and Tubificidae. The taxa richness, diversity index and abundance of sensitive and moderately sensitive macroinvertebrate group were increased after application of ecohydraulic bank stabilization at restored area. The results shown that ecohydraulic bank stabilization structure provides multi-benefits in improving bank stabilization against erosion and providing new micro-habitats for biotic community. Keywords:  ecohydraulic bank stabilization, macroinvertebrates, riparian restoration

  20. Rare and common macroinvertebrates: definition of distribution classes and their boundaries

    NARCIS (Netherlands)

    Nijboer, R.C.; Verdonschot, P.F.M.

    2004-01-01

    Rarity of macroinvertebrates can be used in assessing the ecological quality or conservation value of freshwaters. To select target species for nature conservation and to compare rarity or commonness between regions a classification of species distributions is needed. A distribution classification

  1. Studying the movement behaviour of benthic macroinvertebrates with automated video tracking

    NARCIS (Netherlands)

    Augusiak, J.A.; Brink, van den P.J.

    2015-01-01

    Quantifying and understanding movement is critical for a wide range of questions in basic and applied ecology. Movement ecology is also fostered by technological advances that allow automated tracking for a wide range of animal species. However, for aquatic macroinvertebrates, such detailed methods

  2. Catchment land-use effects on littoral macroinvertebrates in response to local habitat structure and trophic state

    DEFF Research Database (Denmark)

    McGoff, Elaine; Sandin, Leif Leonard

    2012-01-01

    macroinvertebrate community structure: trophic status, substrate variables or riparian variables. We also investigated what influence each of these groups of variables has on the other. The impact of large scale land use patterns was also investigated, to determine if macroinvertebrates responded differently in two...... different catchment land use types: impaired and unimpaired. Partial canonical ordination analysis showed that substrate variables were the most important for describing macroinvertebrate community variation in both catchment land use classes, followed by riparian descriptors, with the trophic signal only...

  3. Coastal Upwelling Drives Intertidal Assemblage Structure and Trophic Ecology.

    Science.gov (United States)

    Reddin, Carl J; Docmac, Felipe; O'Connor, Nessa E; Bothwell, John H; Harrod, Chris

    2015-01-01

    Similar environmental driving forces can produce similarity among geographically distant ecosystems. Coastal oceanic upwelling, for example, has been associated with elevated biomass and abundance patterns of certain functional groups, e.g., corticated macroalgae. In the upwelling system of Northern Chile, we examined measures of intertidal macrobenthic composition, structure and trophic ecology across eighteen shores varying in their proximity to two coastal upwelling centres, in a hierarchical sampling design (spatial scales of >1 and >10 km). The influence of coastal upwelling on intertidal communities was confirmed by the stable isotope values (δ13C and δ15N) of consumers, including a dominant suspension feeder, grazers, and their putative resources of POM, epilithic biofilm, and macroalgae. We highlight the utility of muscle δ15N from the suspension feeding mussel, Perumytilus purpuratus, as a proxy for upwelling, supported by satellite data and previous studies. Where possible, we used corrections for broader-scale trends, spatial autocorrelation, ontogenetic dietary shifts and spatial baseline isotopic variation prior to analysis. Our results showed macroalgal assemblage composition, and benthic consumer assemblage structure, varied significantly with the intertidal influence of coastal upwelling, especially contrasting bays and coastal headlands. Coastal topography also separated differences in consumer resource use. This suggested that coastal upwelling, itself driven by coastline topography, influences intertidal communities by advecting nearshore phytoplankton populations offshore and cooling coastal water temperatures. We recommend the isotopic values of benthic organisms, specifically long-lived suspension feeders, as in situ alternatives to offshore measurements of upwelling influence.

  4. Phytoplankton assemblage of a small, shallow, tropical African reservoir.

    Science.gov (United States)

    Mustapha, Moshood K

    2009-12-01

    I measured physico-chemical properties and phytoplankton in the small, shallow tropical reservoir of Oyun (Offa, Nigeria) between January 2002 and December 2003. I identified 25 phytoplankton genera in three sampling stations. Bacillariophyceae dominated (75.3%), followed by Chlorophyceae (12.2%), Cyanobacteria (11.1%) and Desmidiaceae (0.73%). The high amount of nutrients (e.g. nitrate, phosphate, sulphate and silica) explain phytoplankton heterogeneity (p<0.05). Phytoplankton was abundant during the rainy season, but the transition period had the richest assemblage and abundance. Fluctuations in phytoplankton density were a result of seasonal changes in concentration of nutrients, grazing pressure and reservoir hydrology. The reservoir is eutrophic with excellent water quality and a diverse phytoplankton assemblage: fish production would be high. These conditions resulted from strategies such as watershed best management practices (BMPs) to control eutrophication and sedimentation, and priorities for water usage established through legislation. Additional measures are recommended to prevent oligotrophy, hypereutrophy, excessive phytoplankton bloom, toxic cyanobacteria, and run-off of organic waste and salts.

  5. Consumer–brand assemblages in advertising

    DEFF Research Database (Denmark)

    Bjerrisgaard, Sofie Møller; Kjeldgaard, Dannie; Bengtson, Anders

    2013-01-01

    This paper discusses how the use of tattoos in advertising renders diverse brand–consumer assemblages visible. In considering advertising practitioners as professionals of entanglement, the paper emphasizes the embeddedness of practitioners’ use of tattoo symbolism in institutionalized marketing...... systems and in the cultural history of tattooing. In accordance with recent emphasis on the importance of material devices for understanding contemporary sociality, this paper presents a semiotic analysis of a convenience sample of advertisements depicting tattoos. Tattoos are productive for the study...... potency. This analysis demonstrates how the emergence of brand tattoos in advertising challenges the dominant consumer centrism in consumer research and suggests a networked, emerging understanding of the subject in which agency is distributed in socio-technical assemblages....

  6. Rare species contribute disproportionately to the functional structure of species assemblages.

    Science.gov (United States)

    Leitão, Rafael P; Zuanon, Jansen; Villéger, Sébastien; Williams, Stephen E; Baraloto, Christopher; Fortunel, Claire; Mendonça, Fernando P; Mouillot, David

    2016-04-13

    There is broad consensus that the diversity of functional traits within species assemblages drives several ecological processes. It is also widely recognized that rare species are the first to become extinct following human-induced disturbances. Surprisingly, however, the functional importance of rare species is still poorly understood, particularly in tropical species-rich assemblages where the majority of species are rare, and the rate of species extinction can be high. Here, we investigated the consequences of local and regional extinctions on the functional structure of species assemblages. We used three extensive datasets (stream fish from the Brazilian Amazon, rainforest trees from French Guiana, and birds from the Australian Wet Tropics) and built an integrative measure of species rarity versus commonness, combining local abundance, geographical range, and habitat breadth. Using different scenarios of species loss, we found a disproportionate impact of rare species extinction for the three groups, with significant reductions in levels of functional richness, specialization, and originality of assemblages, which may severely undermine the integrity of ecological processes. The whole breadth of functional abilities within species assemblages, which is disproportionately supported by rare species, is certainly critical in maintaining ecosystems particularly under the ongoing rapid environmental transitions. © 2016 The Author(s).

  7. Multivariate and Spatial Visualisation of Archaeological Assemblages

    Directory of Open Access Journals (Sweden)

    Martin Sterry

    2018-05-01

    Full Text Available Multivariate analyses, in particular correspondence analysis (CA, have become a standard exploratory tool for analysing and interpreting variance in archaeological assemblages. While they have greatly helped analysts, they unfortunately remain abstract to the viewer, all the more so if the viewer has little or no experience with multivariate statistics. A second issue with these analyses can arise from the detachment of archaeological material from its geo-referenced location and typically considered only in terms of arbitrary classifications (e.g. North Europe, Central Europe, South Europe instead of the full range of local conditions (e.g. proximity to other assemblages, relationships with other spatial phenomena. This article addresses these issues by presenting a novel method for spatially visualising CA so that these analyses can be interpreted intuitively. The method works by transforming the resultant bi-plots of the CA into colour maps using the HSV colour model, in which the similarity and difference between assemblages directly corresponds to the similarity and difference of the colours used to display them. Utilising two datasets – ceramics from the excavations of the Roman fortress of Vetera I, and terra sigillata forms collected as part of 'The Samian Project' – the article demonstrates how the method is applied and how it can be used to draw out spatial and temporal trends.

  8. Assemblaged by desire: Potterheads’ productive consumption

    Directory of Open Access Journals (Sweden)

    André Luiz Maranhão de Souza Leão

    2018-02-01

    Full Text Available The Harry Potter saga became one of the cultural products with a major impact on the twenty-first century. Its fans, called potterheads, relate in a social space known as fandom. Their practices are based on the appropriation of the cultural text in a productive consumption process within a context of participatory culture. Assuming desire from the perspective of Deleuzian assemblage theory, which presents this concept as a flow of productive energy that is articulated through a collective force, this study aimed to understand how potterheads’ productive consumption is assemblaged by desire. We therefore explored multifocal data concerning practices of potterheads available on digital platforms using Foucauldian Discourse Analysis. Our results revealed that potterheads’ desire assemblage maintains their bond with the canonical universe of the saga, as a way of maintaining identity and security in the transition to adult life, through relationships in the fandom and in pursuit of broader social legitimacy. The study contributes theoretically by adopting the Deleuzian notion of desire as a lens to understand the collective action of consumers in cultural contexts of practice.

  9. Evaluation of Macroinvertebrate Communities and Habitat for Selected Stream Reaches at Los Alamos National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    L.J. Henne; K.J. Buckley

    2005-08-12

    This is the second aquatic biological monitoring report generated by Los Alamos National Laboratory's (LANL's) Water Quality and Hydrology Group. The study has been conducted to generate impact-based assessments of habitat and water quality for LANL waterways. The monitoring program was designed to allow for the detection of spatial and temporal trends in water and habitat quality through ongoing, biannual monitoring of habitat characteristics and benthic aquatic macroinvertebrate communities at six key sites in Los Alamos, Sandia, Water, Pajarito, and Starmer's Gulch Canyons. Data were collected on aquatic habitat characteristics, channel substrate, and macroinvertebrate communities during 2001 and 2002. Aquatic habitat scores were stable between 2001 and 2002 at all locations except Starmer's Gulch and Pajarito Canyon, which had lower scores in 2002 due to low flow conditions. Channel substrate changes were most evident at the upper Los Alamos and Pajarito study reaches. The macroinvertebrate Stream Condition Index (SCI) indicated moderate to severe impairment at upper Los Alamos Canyon, slight to moderate impairment at upper Sandia Canyon, and little or no impairment at lower Sandia Canyon, Starmer's Gulch, and Pajarito Canyon. Habitat, substrate, and macroinvertebrate data from the site in upper Los Alamos Canyon indicated severe impacts from the Cerro Grande Fire of 2000. Impairment in the macroinvertebrate community at upper Sandia Canyon was probably due to effluent-dominated flow at that site. The minimal impairment SCI scores for the lower Sandia site indicated that water quality improved with distance downstream from the outfall at upper Sandia Canyon.

  10. Promoting a functional macroinvertebrate approach in the biomonitoring of Italian lotic systems

    Directory of Open Access Journals (Sweden)

    Richard W. Merritt

    2016-06-01

    Full Text Available Over fifty years of research on freshwater macroinvertebrates has been driven largely by the state of the taxonomy of these organisms. Significant advances have been and continue to be made in developing ever more refined keys to macroinvertebrate groups. When advances in macroinvertebrate ecological research are restricted by the level of detail in identifications, then analysis by function is a viable alternative. The focus on function, namely adaptations of macroinvertebrates to habitats and the utilization of food resources, has facilitated ecological evaluation of freshwater ecosystems. This classification is based not on what insects eat, but how they obtain their food. These categories are called 'functional feeding groups', as the name implies, denoting their functional role when describing how and where they feed. This is the basis for the functional feeding group (FFG method that was initially developed in the early 1960s. Taxonomy is applied only to the level of detail that allows assignment to one of five functional feeding group categories: detrital shredders, scrapers, filtering collectors, gatherers, and predators. The aim of this short communication, originating from the presentation of R.W. Merritt at the Biomonitoring Symposium in Rome, 2015, is to promote the use of a functional approach in biomonitoring, especially in Italian and European lotic systems. Here, we present two case studies and we discuss the advantages of the method, especially considering the great availability of quantitative data on macroinvertebrates after the implementation of the WFD 2000/60. We are confident that the increase of functional assessment of ecosystem attributes could have important and direct repercussions in the understanding and management of running waters.

  11. Local environment rather than past climate determines community composition of mountain stream macroinvertebrates across Europe.

    Science.gov (United States)

    Múrria, Cesc; Bonada, Núria; Vellend, Mark; Zamora-Muñoz, Carmen; Alba-Tercedor, Javier; Sainz-Cantero, Carmen Elisa; Garrido, Josefina; Acosta, Raul; El Alami, Majida; Barquín, Jose; Derka, Tomáš; Álvarez-Cabria, Mario; Sáinz-Bariain, Marta; Filipe, Ana F; Vogler, Alfried P

    2017-11-01

    Community assembly is determined by a combination of historical events and contemporary processes that are difficult to disentangle, but eco-evolutionary mechanisms may be uncovered by the joint analysis of species and genetic diversity across multiple sites. Mountain streams across Europe harbour highly diverse macroinvertebrate communities whose composition and turnover (replacement of taxa) among sites and regions remain poorly known. We studied whole-community biodiversity within and among six mountain regions along a latitudinal transect from Morocco to Scandinavia at three levels of taxonomic hierarchy: genus, species and haplotypes. Using DNA barcoding of four insect families (>3100 individuals, 118 species) across 62 streams, we found that measures of local and regional diversity and intraregional turnover generally declined slightly towards northern latitudes. However, at all hierarchical levels we found complete (haplotype) or high (species, genus) turnover among regions (and even among sites within regions), which counters the expectations of Pleistocene postglacial northward expansion from southern refugia. Species distributions were mostly correlated with environmental conditions, suggesting a strong role of lineage- or species-specific traits in determining local and latitudinal community composition, lineage diversification and phylogenetic community structure (e.g., loss of Coleoptera, but not Ephemeroptera, at northern sites). High intraspecific genetic structure within regions, even in northernmost sites, reflects species-specific dispersal and demographic histories and indicates postglacial migration from geographically scattered refugia, rather than from only southern areas. Overall, patterns were not strongly concordant across hierarchical levels, but consistent with the overriding influence of environmental factors determining community composition at the species and genus levels. © 2017 John Wiley & Sons Ltd.

  12. Effects of repeated insecticide pulses on macroinvertebrate drift in indoor stream mesocosms.

    Science.gov (United States)

    Berghahn, Rüdiger; Mohr, Silvia; Hübner, Verena; Schmiediche, Ronny; Schmiedling, Ina; Svetich-Will, Erkki; Schmidt, Ralf

    2012-10-15

    Pesticide contaminations via run-off or spray drift have been reported to result in the mass drift of macroinvertebrates as well as causing structural and functional changes of the corresponding stream sections. However, pesticide pulses in the field are associated with sudden increases in flow velocity, water turbidity, and changes in water temperature, which can also induce drift. Only through replicated community testing under highly controlled conditions can these effects be disentangled. In a stream mesocosm study, 12-h pulses of 12 μg/L imidacloprid were set three times at weekly intervals and are considered a "pulse series". Two pulse series of this neonicotinoid insecticide were run in both spring and summer with 4 treatment and 4 control stream mesocosms used in each pulse series. Prior to the start of the mesocosm experiment, both pulse concentration and duration had been screened for drift responses in larval Baetidae, Chironomidae and adult Gammarus roeseli in laboratory experiments. In the subsequent mesocosm study, each pulse caused a pronounced increase in the drift of insect larvae and gammarids. The drift response was taxon-specific, which was related to preferred habitat and exposure to other stressors like current velocity, in addition to imidacloprid sensitivity. Activity measurements employing a Multispecies Freshwater Biomonitor(®) revealed that in Baetis sp. the diurnal activity pattern became more pronounced even 12h after the pulse though with slightly decreased mean physical activity. Adult G. roeseli showed a drastic pulse by pulse decrease in physical activity which after the 3rd pulse lasted longer than 24h. In conclusion, drift is a sensitive, ecologically relevant endpoint and should be regarded when a specific risk assessment for lotic surface waters is done, e.g. in the context of a spatially explicit risk assessment. Copyright © 2012 Elsevier B.V. All rights reserved.

  13. Life history theory predicts fish assemblage response to hydrologic regimes.

    Science.gov (United States)

    Mims, Meryl C; Olden, Julian D

    2012-01-01

    The hydrologic regime is regarded as the primary driver of freshwater ecosystems, structuring the physical habitat template, providing connectivity, framing biotic interactions, and ultimately selecting for specific life histories of aquatic organisms. In the present study, we tested ecological theory predicting directional relationships between major dimensions of the flow regime and life history composition of fish assemblages in perennial free-flowing rivers throughout the continental United States. Using long-term discharge records and fish trait and survey data for 109 stream locations, we found that 11 out of 18 relationships (61%) tested between the three life history strategies (opportunistic, periodic, and equilibrium) and six hydrologic metrics (two each describing flow variability, predictability, and seasonality) were statistically significant (P history strategies, with 82% of all significant relationships observed supporting predictions from life history theory. Specifically, we found that (1) opportunistic strategists were positively related to measures of flow variability and negatively related to predictability and seasonality, (2) periodic strategists were positively related to high flow seasonality and negatively related to variability, and (3) the equilibrium strategists were negatively related to flow variability and positively related to predictability. Our study provides important empirical evidence illustrating the value of using life history theory to understand both the patterns and processes by which fish assemblage structure is shaped by adaptation to natural regimes of variability, predictability, and seasonality of critical flow events over broad biogeographic scales.

  14. How could discharge management affect Florida spring fish assemblage structure?

    Science.gov (United States)

    Work, Kirsten; Codner, Keneil; Gibbs, Melissa

    2017-08-01

    Freshwater bodies are increasingly affected by reductions in water quantity and quality and by invasions of exotic species. To protect water quantity and maintain the ecological integrity of many water bodies in central Florida, a program of adopting Minimum Flows and Levels (MFLs) has begun for both lentic and lotic waters. The purpose of this study was to determine whether there were relationships between discharge and stage, water quality, and biological parameters for Volusia Blue Spring, a first magnitude spring (discharge > 380,000 m 3 day -1 or 100 mgd) for which an MFL program was adopted in 2006. Over the course of fourteen years, we assessed fish density and diversity weekly, monthly, or seasonally with seine and snorkel counts. We evaluated annual changes in the assemblages for relationships with water quantity and quality. Low discharge and dissolved oxygen combined with high stage and conductivity produced a fish population with a lower density and diversity in 2014 than in previous years. Densities of fish taxonomic/functional groups also were low in 2014 and measures of water quantity were significant predictors of fish assemblage structure. As a result of the strong relationships between variation in discharge and an array of chemical and biological characteristics of the spring, we conclude that maintaining the historical discharge rate is important for preserving the ecological integrity of Volusia Blue Spring. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Influence of landscape structure on reef fish assemblages

    Science.gov (United States)

    Grober-Dunsmore, R.; Frazer, T.K.; Beets, J.P.; Lindberg, W.J.; Zwick, P.; Funicelli, N.A.

    2008-01-01

    Management of tropical marine environments calls for interdisciplinary studies and innovative methodologies that consider processes occurring over broad spatial scales. We investigated relationships between landscape structure and reef fish assemblage structure in the US Virgin Islands. Measures of landscape structure were transformed into a reduced set of composite indices using principal component analyses (PCA) to synthesize data on the spatial patterning of the landscape structure of the study reefs. However, composite indices (e.g., habitat diversity) were not particularly informative for predicting reef fish assemblage structure. Rather, relationships were interpreted more easily when functional groups of fishes were related to individual habitat features. In particular, multiple reef fish parameters were strongly associated with reef context. Fishes responded to benthic habitat structure at multiple spatial scales, with various groups of fishes each correlated to a unique suite of variables. Accordingly, future experiments should be designed to test functional relationships based on the ecology of the organisms of interest. Our study demonstrates that landscape-scale habitat features influence reef fish communities, illustrating promise in applying a landscape ecology approach to better understand factors that structure coral reef ecosystems. Furthermore, our findings may prove useful in design of spatially-based conservation approaches such as marine protected areas (MPAs), because landscape-scale metrics may serve as proxies for areas with high species diversity and abundance within the coral reef landscape. ?? 2007 Springer Science+Business Media B.V.

  16. Long Term Resource Monitoring Program Annual Status Report, 1999: Macroinvertebrate Sampling in Six Reaches of the Upper Mississippi River System

    National Research Council Canada - National Science Library

    Sauer, Jennifer

    2000-01-01

    In 1992, macroinvertebrate sampling was initiated in Pools 4, 8, 13, 26, and the Open River reach of the Mississippi River, and La Orange Pool of the Illinois River as part of the Long Term Resource Monitoring Program...

  17. Effects of brine contamination from energy development on wetland macroinvertebrate community structure in the Prairie Pothole Region

    Science.gov (United States)

    Preston, Todd M.; Borgreen, Michael J.; Ray, Andrew M.

    2018-01-01

    Wetlands in the Prairie Pothole Region (PPR) of North America support macroinvertebrate communities that are integral to local food webs and important to breeding waterfowl. Macroinvertebrates in PPR wetlands are primarily generalists and well adapted to within and among year changes in water permanence and salinity. The Williston Basin, a major source of U.S. energy production, underlies the southwest portion of the PPR. Development of oil and gas results in the coproduction of large volumes of highly saline, sodium chloride dominated water (brine) and the introduction of brine can alter wetland salinity. To assess potential effects of brine contamination on macroinvertebrate communities, 155 PPR wetlands spanning a range of hydroperiods and salinities were sampled between 2014 and 2016. Brine contamination was documented in 34 wetlands with contaminated wetlands having significantly higher chloride concentrations, specific conductance and percent dominant taxa, and significantly lower taxonomic richness, Shannon diversity, and Pielou evenness scores compared to uncontaminated wetlands. Non-metric multidimensional scaling found significant correlations between several water quality parameters and macroinvertebrate communities. Chloride concentration and specific conductance, which can be elevated in naturally saline wetlands, but are also associated with brine contamination, had the strongest correlations. Five wetland groups were identified from cluster analysis with many of the highly contaminated wetlands located in a single cluster. Low or moderately contaminated wetlands were distributed among the remaining clusters and had macroinvertebrate communities similar to uncontaminated wetlands. While aggregate changes in macroinvertebrate community structure were observed with brine contamination, systematic changes were not evident, likely due to the strong and potentially confounding influence of hydroperiod and natural salinity. Therefore, despite the observed

  18. Diversity and abundance of aquatic macroinvertebrates in a lotic environment in Midwestern São Paulo State, Brazil

    Directory of Open Access Journals (Sweden)

    Gabriel Lucas Bochini

    2009-04-01

    Full Text Available This study analyzed the diversity and abundance of an aquatic macroinvertebrate community in the Vargem Limpa stream located in Bauru, Midwestern São Paulo State, and characterized the water quality based on biological parameters. The sampling was carried out during the rain season (December, 2004. It was analyzed and identified 3,068 organisms belonging to 9 macroinvertebrate families. The system showed low richness and diversity of organisms in response to water quality.

  19. Biodiversity patterns of macrophyte and macroinvertebrate communities in two lagoons of Western Greece.

    Science.gov (United States)

    Fyttis, G.; Reizopoulou, S.; Papastergiadou, E.

    2012-04-01

    Aquatic macrophytes and benthic macroinvertebrates were studied seasonally (Spring, Autumn, Summer) between the years 2009 - 2011 in two coastal lagoons (Kotychi and Prokopos) located in Peloponnese, Greece, in order to investigate spatial and temporal biodiversity trends related to hydrological processes (degree of confinement, nitrates, phosphates, chl-a, total suspended materials, light irradiance, pH, salinity, temperature and dissolved oxygen). Kotychi lagoon presents a better communication with the sea, while Prokopos has a high degree of confinement. Both ecosystems seasonally receive freshwater input from streams. The submerged aquatic macrophytes constituted a major component of the ecosystems studied. In total, 22 taxa of aquatic macrophytes (angiosperms and macroalgae), 16 taxa for Kotychi (2 Rhodophyta, 8 Chlorophyta, 5 Magnoliophyta, 1 Streptophyta) and 14 taxa for Prokopos (1 Rhodophyta, 5 Chlorophyta, 5 Magnoliophyta, 3 Streptophyta) were found. Ruppia cirrhosa, and Potamogeton pectinatus were dominant in both lagoons. Kotychi lagoon was also dominated by Zostera noltii and Prokopos by Zannichellia pallustris ssp. pedicellata, while the biomass of aquatic species peaked during the summer periods, in both lagoons. The total number of macroinvertebrates found in the lagoons was 28 taxa for Kotychi and 19 for Prokopos. Chironomidae were dominant in both lagoons, while Kotychi was also dominated by Lekanesphaera monodi and Monocorophium insidiosum, and Prokopos by Ostracoda and Lekanesphaera monodi. Benthic diversity ranged from 1.33 to 2.57 in Kotychi and from 0.67 to 2.48 in Prokopos. Species richness, diversity, and abundance of benthic macroinvertebrates were strongly related to aquatic vegetation and to the degree of communication with the marine environment. Moreover, species richness and abundance of both macrophytes and macroinvertebrates were mainly dependent on depth, temperature, pH and concentration of total suspended materials (TSM). Results

  20. Impacts of Sedimentation from Oil and Gas Development on Stream Macroinvertebrates in Two Adjacent Watersheds of the Allegheny National Forest of Northwestern Pennsylvania

    Energy Technology Data Exchange (ETDEWEB)

    Fritz, K.; Harris, S.; Edenborn, H.M.; Sams, J.

    2011-01-01

    Fritz, Kelley'*, Steven Harris', Harry Edenborn2, and James Sams2. 'Clarion University of Pennsylvania, Clarion, PA 16214, 2National Energy Technology Laboratory, U.S. Dept. Energy, Pittsburgh, PA 15236. Impacts a/Sedimentation/rom Oil and Gas Development on Stream Macroinvertebrates in Two Adjacent Watersheds a/the Allegheny National Forest a/Northwestern Pennsylvania - The Allegheny National Forest (ANF), located in northwestern Pennsy Ivania, is a multiuse forest combining commercial development with recreational and conservation activities. As such, portions of the ANF have been heavily logged and are now the subject of widespread oil and gas development. This rapid increase in oil and gas development has led to concerns about sediment runoff from the dirt and gravel roads associated with development and the potential impact on the aquatic biota of the receiving streams. We examined and compared the benthic macroinvertebrate communities in two adjacent watersheds of similar size and topography in the ANF; the Hedgehog Run watershed has no oil and gas development, while the adjacent Grunder Run watershed has extensive oil and gas development. In Hedgehog and Grunder Run, we collected monthly kicknet samples from riffles and glides at two sites from April to October 2010. At the same intervals, we measured standard water quality parameters, including conductivity and turbidity. Preliminary results have indicated much higher turbidity in Grunder Run, but little difference in the diversity and abundance of benthic macro invertebrates inhabiting the two streams.

  1. Preliminary study of some environmental and ecological aspects of the communities of fish and aquatic macro-invertebrates in the Tutunendo River, Choco, Colombia

    International Nuclear Information System (INIS)

    Torres, Yenecith; Roldan, Gabriel; Asprilla, Sonia; Rivas, Tulia Sofia

    2006-01-01

    From June to October 2003 studies related to environmental and ecological aspects of fishes and macro-invertebrates in three sampling stations of Tutunendo River located in the Department of Choco, Colombia, were carried out. Abiotic factors like conductivity, pH, oxygen and temperature were also measured. Eighty one hundred fish specimens, belonging to three orders, seven families and twelve species were collected. The order Siluriformes presented the greatest abundance (70.72%) with three families, seven species and 128 specimens, followed by Characiformes with three families, three species and 43 specimens (23.53%). At the same time 1.211 aquatic macro-invertebrates were collected represented by the orders Ephemeroptera (50.28%), Odonata (11.40%), Coleoptera (8.67%), Hemiptera (8.42%), Trichoptera (7.30%), Plecoptera (5.7%), Megaloptera (3.3%), Lepidoptera (2.31%), Diptera (0.37%) and Haplotaxida (0.08%). The families Leptophlebiidae (37.24%), followed by Naucoridae (8.42%) and Baetidae (8%) were the most represented. Relationship between fishes and macro invertebrates as food items in Geophagus pellegrini and Astyanaxfasciatus were also studied. G. pellegrini was zooplanctophage with preference for Baetidae, Leptohyphidae, Hydrobiosidae, Leptoceridae and Naucoridae. Finally, the present work indicated that Tutunendo town does not have potential fishery; the economy is supported in productive traditional systems based in the agriculture, complemented with fishery and extractive activities

  2. Macroinvertebrate Prey Availability and Fish Diet Selectivity in Relation to Environmental Variables in Natural and Restoring North San Francisco Bay Tidal Marsh Channels

    OpenAIRE

    Emily R. Howe; Charles A. Simenstad; Jason D. Toft; Jeffrey R. Cordell; Stephen M. Bollens

    2014-01-01

    Tidal marsh wetlands provide important foraging habitat for a variety of estuarine fishes. Prey organisms include benthic–epibenthic macroinvertebrates, neustonic arthropods, and zooplankton. Little is known about the abundance and distribution of interior marsh macroinvertebrate communities in the San Francisco Estuary (estuary). We describe seasonal, regional, and site variation in the composition and abundance of neuston and benthic–epibenthic macroinvertebrates that inhabit tidal marsh ch...

  3. Moral assemblages of volunteer tourism development in Cusco, Peru

    OpenAIRE

    Burrai, Elisa.; Mostafanezhad, Mary.; Hannam, Kevin.

    2016-01-01

    In this paper, we develop a conceptual approach from which to examine the moral landscape of volunteer tourism development in Cusco, Peru. Drawing from recent work on assemblage theory in geography and tourism studies, we explore how assemblage thinking can facilitate new understandings of volunteer tourism development. Using assemblage as an analytical framework allows us to understand volunteer tourism as a series of relational, processual, unequal and mobile practices. These practices, we ...

  4. Effects of grade control structures on fish passage, biological assemblages, and hydraulic environments in western Iowa streams: a multidisciplinary review

    Science.gov (United States)

    Thomas, J.T.; Culler, M.E.; Dermisis, D.C.; Pierce, Clay; Papanicolaou, A.N.; Stewart, T.W.; Larson, C.J.

    2011-01-01

    Land use changes and channelization of streams in the deep loess region of western Iowa have led to stream channel incision, altered flow regimes, increased sediment inputs, decreased habitat diversity and reduced lateral connectivity of streams and floodplains. Grade control structures (GCSs) are built in streams to prevent further erosion, protect infrastructure and reduce sediment loads. However, GCS can have a detrimental impact on fisheries and biological communities. We review three complementary biological and hydraulic studies on the effects of GCS in these streams. GCS with steep (≥1:4 rise : run) downstream slopes severely limited fish passage, but GCS with gentle slopes (≤1:15) allowed greater passage. Fish assemblages were dominated by species tolerant of degradation, and Index of Biotic Integrity (IBI) scores were indicative of fair or poor biotic integrity. More than 50% of fish species had truncated distributions. After modification of GCS to reduce slopes and permit increased passage, IBI scores increased and several species were detected further upstream than before modification. Total macroinvertebrate density, biomass and taxonomic diversity and abundance of ecologically sensitive taxa were greater at GCS than in reaches immediately upstream, downstream or ≥1 km from GCS. A hydraulic study confirmed results from fish passage studies; minimum depths and maximum current velocities at GCS with gentle slopes (≤1:15) were more likely to meet minimum criteria for catfish passage than GCS with steeper slopes. Multidisciplinary approaches such as ours will increase understanding of GCS-associated factors influencing fish passage, biological assemblage structure and other ecological relationships in streams.

  5. Relationships between indicators of acid-base chemistry and fish assemblages in streams of the Great Smoky Mountains National Park

    Science.gov (United States)

    Baldigo, Barry P.; Kulp, Matt A.; Schwartz, John S.

    2018-01-01

    The acidity of many streams in the Great Smoky Mountains National Park (GRSM) has increased significantly since pre-industrial (∼1850) times due to the effects of highly acidic atmospheric deposition in poorly buffered watersheds. Extensive stream-monitoring programs since 1993 have shown that fish and macroinvertebrate assemblages have been adversely affected in many streams across the GRSM. Matching chemistry and fishery information collected from 389 surveys performed at 52 stream sites over a 22-year period were assessed using logistic regression analysis to help inform the U.S. Environmental Protection Agency’s assessment of the environmental impacts of emissions of oxides of nitrogen (NOx) and sulfur (SOx). Numerous logistic equations and associated curves were derived that defined the relations between acid neutralizing capacity (ANC) or pH and different levels of community richness, density, and biomass; and density and biomass of brook trout, rainbow trout, and small prey (minnow) populations in streams of the GRSM. The equations and curves describe the status of fish assemblages in the GRSM under contemporary emission levels and deposition loads of nitrogen (N) and sulfur (S) and provide a means to estimate how newly proposed (and various alternative) target deposition loads, which strongly influence stream ANC, might affect key ecological indicators. Several examples using ANC, community richness, and brook trout density are presented to illustrate the steps needed to predict how future changes in stream chemistry (resulting from different target deposition loads of N and S) will affect the probabilities of observing specific levels of selected biological indicators in GRSM streams. The implications of this study to the regulation of NOx and SOx emissions, water quality, and fisheries management in streams of the GRSM are discussed, but also qualified by the fact that specific examples provided need to be further explored before recommendations

  6. Use of macroinvertebrates to identify cultivated wetlands in the Prairie Pothole Region

    Science.gov (United States)

    Euliss, Ned H.; Mushet, David M.; Johnson, Douglas H.

    2001-01-01

    We evaluated the use of macroinvertebrates as a potential tool to identify dry and intensively farmed temporary and seasonal wetlands in the Prairie Pothole Region. The techniques we designed and evaluated used the dried remains of invertebrates or their egg banks in soils as indicators of wetlands. For both the dried remains of invertebrates and their egg banks, we weighted each taxon according to its affinity for wetlands or uplands. Our study clearly demonstrated that shells, exoskeletons, head capsules, eggs, and other remains of macroinvertebrates can be used to identify wetlands, even when they are dry, intensively farmed, and difficult to identify as wetlands using standard criteria (i.e., hydrology, hydrophytic vegetation, and hydric soils). Although both dried remains and egg banks identified wetlands, the combination was more useful, especially for identifying drained or filled wetlands. We also evaluated the use of coarse taxonomic groupings to stimulate use of the technique by nonspecialists and obtained satisfactory results in most situations.

  7. Holocene molluscan assemblages in the Magellan region

    Directory of Open Access Journals (Sweden)

    Sandra Gordillo

    1999-12-01

    Full Text Available In the Magellan region, much of the shoreline of the Beagle Channel coast (54°53´S; 67° - 68°W is bordered by Holocene raised beaches, which contain a large number of molluscs and other shelled taxa. The purpose of this work is to document the presence of various molluscan assemblages deposited with little or no postmortem transportation. An epifaunal Chlamys patagonica palaeocommunity (ca. 8,000 - 7,000 BP and three infaunal (Tawera gayi, Ameghinomya antiqua - Hiatella solida and Ameghinomya antiqua - Ensis macha palaeocommunities (ca. 4,400 - 4,000 BP were recognized. All the assemblages studied represent shallow, subtidal, cold-temperate environments. Based on comparisons with modern benthic communities in this region, these associations show that no remarkable ecologic and climatic changes occurred during the period ca. 8,000 - 4,000 BP. Thus, an apparent stability of modern marine communities over a period of several thousand years is suggested.

  8. Techniques de formage et d'assemblage

    CERN Document Server

    Favre, G; CERN. Geneva. TS Department

    2004-01-01

    Les sections Techniques d'Assemblage du groupe EST/MF et Brasage du groupe EST/SM ont été groupées en un seul service dans un but de rationalisation accrue des ressources et méthodes. Ce service dispose de nombreux moyens : soudure et découpe LASER (YAG, 350 W), soudure par faisceau d'électrons (deux installations, 35 et 7.5 kW), équipements TIG orbital, jet line, MIG, soudure plasma, boîte à gants, portique de soudage trois axes multiprocédés, presses plieuses, rouleuses, moyens de repoussage, alimentation à induction 12 kW et divers fours sous vide et à air. Le service est composé de 17 personnes dont la polyvalence est encouragée. Les activités de la section seront décrites à travers quelques exemples significatifs récents, notamment : l'assemblage des amenées de courant HTS, la réalisation des chambres LSS, des tubes HET, d'enveloppes céramiques pour détecteurs PET-HPD, le brasage de RFQ, la soudure du Barrel d'ATLAS ou encore le soudage des lignes de thermalisation du toroïde d'AT...

  9. Reservoir floodplains support distinct fish assemblages

    Science.gov (United States)

    Miranda, Leandro E.; Wigen, S. L.; Dagel, Jonah D.

    2014-01-01

    Reservoirs constructed on floodplain rivers are unique because the upper reaches of the impoundment may include extensive floodplain environments. Moreover, reservoirs that experience large periodic water level fluctuations as part of their operational objectives seasonally inundate and dewater floodplains in their upper reaches, partly mimicking natural inundations of river floodplains. In four flood control reservoirs in Mississippi, USA, we explored the dynamics of connectivity between reservoirs and adjacent floodplains and the characteristics of fish assemblages that develop in reservoir floodplains relative to those that develop in reservoir bays. Although fish species richness in floodplains and bays were similar, species composition differed. Floodplains emphasized fish species largely associated with backwater shallow environments, often resistant to harsh environmental conditions. Conversely, dominant species in bays represented mainly generalists that benefit from the continuous connectivity between the bay and the main reservoir. Floodplains in the study reservoirs provided desirable vegetated habitats at lower water level elevations, earlier in the year, and more frequently than in bays. Inundating dense vegetation in bays requires raising reservoir water levels above the levels required to reach floodplains. Therefore, aside from promoting distinct fish assemblages within reservoirs and helping promote diversity in regulated rivers, reservoir floodplains are valued because they can provide suitable vegetated habitats for fish species at elevations below the normal pool, precluding the need to annually flood upland vegetation that would inevitably be impaired by regular flooding. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

  10. Macroinvertebrate short-term responses to flow variation and oxygen depletion: A mesocosm approach.

    Science.gov (United States)

    Calapez, Ana R; Branco, Paulo; Santos, José M; Ferreira, Teresa; Hein, Thomas; Brito, António G; Feio, Maria João

    2017-12-01

    In Mediterranean rivers, water scarcity is a key stressor with direct and indirect effects on other stressors, such as water quality decline and inherent oxygen depletion associated with pollutants inputs. Yet, predicting the responses of macroinvertebrates to these stressors combination is quite challenging due to the reduced available information, especially if biotic and abiotic seasonal variations are taken under consideration. This study focused on the response of macroinvertebrates by drift to single and combined effects of water scarcity and dissolved oxygen (DO) depletion over two seasons (winter and spring). A factorial design of two flow velocity levels - regular and low (vL) - with three levels of oxygen depletion - normoxia, medium depletion (dM) and higher depletion (dH) - was carried out in a 5-artificial channels system, in short-term experiments. Results showed that both stressors individually and together had a significant effect on macroinvertebrate drift ratio for both seasons. Single stressor effects showed that macroinvertebrate drift decreased with flow velocity reduction and increased with DO depletion, in both winter and spring experiments. Despite single stressors opposing effects in drift ratio, combined stressors interaction (vL×dM and vL×dH) induced a positive synergistic drift effect for both seasons, but only in winter the drift ratio was different between the levels of DO depletion. Stressors interaction in winter seemed to intensify drift response when reached lower oxygen saturation. Also, drift patterns were different between seasons for all treatments, which may depend on individual's life stage and seasonal behaviour. Water scarcity seems to exacerbate the oxygen depletion conditions resulting into a greater drifting of invertebrates. The potential effects of oxygen depletion should be evaluated when addressing the impacts of water scarcity on river ecosystems, since flow reductions will likely contribute to a higher oxygen

  11. Evaluation of alternative macroinvertebrate sampling techniques for use in a new tropical freshwater bioassessment scheme

    OpenAIRE

    Isabel Eleanor Moore; Kevin Joseph Murphy

    2015-01-01

    Aim: The study aimed to determine the effectiveness of benthic macroinvertebrate dredge net sampling procedures as an alternative method to kick net sampling in tropical freshwater systems, specifically as an evaluation of sampling methods used in the Zambian Invertebrate Scoring System (ZISS) river bioassessment scheme. Tropical freshwater ecosystems are sometimes dangerous or inaccessible to sampling teams using traditional kick-sampling methods, so identifying an alternative procedure that...

  12. Disentangling the effects of low pH and metal mixture toxicity on macroinvertebrate diversity

    Science.gov (United States)

    Fornaroli, Riccardo; Ippolito, Alessio; Tolkkinen, Mari J.; Mykrä, Heikki; Muotka, Timo; Balistrieri, Laurie S.; Schmidt, Travis S.

    2018-01-01

    One of the primary goals of biological assessment of streams is to identify which of a suite of chemical stressors is limiting their ecological potential. Elevated metal concentrations in streams are often associated with low pH, yet the effects of these two potentially limiting factors of freshwater biodiversity are rarely considered to interact beyond the effects of pH on metal speciation. Using a dataset from two continents, a biogeochemical model of the toxicity of metal mixtures (Al, Cd, Cu, Pb, Zn) and quantile regression, we addressed the relative importance of both pH and metals as limiting factors for macroinvertebrate communities. Current environmental quality standards for metals proved to be protective of stream macroinvertebrate communities and were used as a starting point to assess metal mixture toxicity. A model of metal mixture toxicity accounting for metal interactions was a better predictor of macroinvertebrate responses than a model considering individual metal toxicity. We showed that the direct limiting effect of pH on richness was of the same magnitude as that of chronic metal toxicity, independent of its influence on the availability and toxicity of metals. By accounting for the direct effect of pH on macroinvertebrate communities, we were able to determine that acidic streams supported less diverse communities than neutral streams even when metals were below no-effect thresholds. Through a multivariate quantile model, we untangled the limiting effect of both pH and metals and predicted the maximum diversity that could be expected at other sites as a function of these variables. This model can be used to identify which of the two stressors is more limiting to the ecological potential of running waters.

  13. Soil macroinvertebrate communities across a productivity gradient in deciduous forests of eastern North America

    Science.gov (United States)

    Evelyn S. Wenk; Mac A. Callaham; Joseph O' Brien; Paul J. Hanson

    2016-01-01

    Within the temperate, deciduous forests of the eastern US, diverse soil-fauna communities are structured by a combination of environmental gradients and interactions with other biota. The introduction of non-native soil taxa has altered communities and soil processes, and adds another degree of variability to these systems. We sampled soil macroinvertebrate abundance...

  14. Benthic macroinvertebrates as ecological indicators for estuarine and coastal ecosystems : assessment and intercalibration

    OpenAIRE

    Teixeira, Heliana Lilita Gonçalves

    2010-01-01

    Tese de doutoramento em Biologia (Ecologia) apresentada à Faculdade de Ciências e Tecnologia da Universidade de Coimbra The aim of the research work presented in this thesis is to be a contribution to the field of ecological assessment in coastal and transitional ecosystems. The main goals were: a) to present a method for the assessment of the ecological status of benthic macroinvertebrate communities in Portuguese transitional waters that would meet the requirements of the Eur...

  15. Aquatic macroinvertebrate diversity and composition in streams along an altitudinal gradient in Southeastern Brazil

    OpenAIRE

    Henriques-Oliveira, Ana Lucia; Nessimian, Jorge Luiz

    2010-01-01

    Aquatic macroinvertebrate diversity and composition in streams along an altitudinal gradient in Southeastern Brazil. A study concerning taxonomic richness and composition of the aquatic insect fauna in streams within the same catchment basin along an altitudinal gradient in Southeast Brazil, was conducted to test the hypothesis that there is a faunal discontinuity in the biocenotic composition, related to differences in altitude and latitude. In Southeastern Brazil, around latitude 22°, this ...

  16. Results of Macroinvertebrate Sampling Conducted at 33 SRS Stream Locations, July--August 1993

    Energy Technology Data Exchange (ETDEWEB)

    Specht, W.L.

    1994-12-01

    In order to assess the health of the macroinvertebrate communities of SRS streams, the macroinvertebrate communities at 30 stream locations on SRS were sampled during the summer of 1993, using Hester-Dendy multiplate samplers. In addition, three off-site locations in the Upper Three Runs drainage were sampled in order to assess the potential for impact from off-site activities. In interpreting the data, it is important to recognize that these data were from a single set of collections. Macroinvertebrate communities often undergo considerable temporal variation, and are also greatly influenced by such factors as water depth, water velocity, and available habitat. These stations were selected with the intent of developing an on-going sampling program at a smaller number of stations, with the selection of the stations to be based largely upon the results of this preliminary sampling program. When stations within a given stream showed similar results, fewer stations would be sampled in the future. Similarly, if a stream appeared to be perturbed, additional stations or chemical analyses might be added so that the source of the perturbation could be identified. In general, unperturbed streams will contain more taxa than perturbed streams, and the distribution of taxa among orders or families will differ. Some groups of macroinvertebrates, such as Ephemeroptera (mayflies), Plecoptera (stoneflies) and Trichoptera (caddisflies), which are collectively called EPT taxa, are considered to be relatively sensitive to most kinds of stream perturbation; therefore a reduced number of EPT taxa generally indicates that the stream has been subject to chemical or physical stressors. In coastal plain streams, EPT taxa are generally less dominant than in streams with rocky substrates, while Chironomidae (midges) are more abundant. (Abstract Truncated)

  17. Disentangling the effects of low pH and metal mixture toxicity on macroinvertebrate diversity.

    Science.gov (United States)

    Fornaroli, Riccardo; Ippolito, Alessio; Tolkkinen, Mari J; Mykrä, Heikki; Muotka, Timo; Balistrieri, Laurie S; Schmidt, Travis S

    2018-04-01

    One of the primary goals of biological assessment of streams is to identify which of a suite of chemical stressors is limiting their ecological potential. Elevated metal concentrations in streams are often associated with low pH, yet the effects of these two potentially limiting factors of freshwater biodiversity are rarely considered to interact beyond the effects of pH on metal speciation. Using a dataset from two continents, a biogeochemical model of the toxicity of metal mixtures (Al, Cd, Cu, Pb, Zn) and quantile regression, we addressed the relative importance of both pH and metals as limiting factors for macroinvertebrate communities. Current environmental quality standards for metals proved to be protective of stream macroinvertebrate communities and were used as a starting point to assess metal mixture toxicity. A model of metal mixture toxicity accounting for metal interactions was a better predictor of macroinvertebrate responses than a model considering individual metal toxicity. We showed that the direct limiting effect of pH on richness was of the same magnitude as that of chronic metal toxicity, independent of its influence on the availability and toxicity of metals. By accounting for the direct effect of pH on macroinvertebrate communities, we were able to determine that acidic streams supported less diverse communities than neutral streams even when metals were below no-effect thresholds. Through a multivariate quantile model, we untangled the limiting effect of both pH and metals and predicted the maximum diversity that could be expected at other sites as a function of these variables. This model can be used to identify which of the two stressors is more limiting to the ecological potential of running waters. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. Assessing the ecological status of the Cisadane River’s headwaters using benthic macroinvertebrates

    Science.gov (United States)

    Krisanti, M.; Wardiatno, Y.; Anzani, Y. M.

    2017-01-01

    Benthic macroinvertebrates are commonly used in river health biomonitoring. In monitoring program biotic indices are now widely established in water quality monitoring around the world, including in the tropical countries. The aim of this study was to reveal the ecological status of Cisadane River’s headwaters in inside and outside of Mount Halimun-Salak National Park by using benthic macroinvertebrates. The research was conducted in the headwaters of Cisadane River located in Mount Halimun-Salak National Park. Macroinvertebrates were collected from four sites, i.e. inside the park (station 1, 2, 3, and 4) and from two sites outside the park (station 5 and 6). Collections were made twice a month, starting from April to June 2015 by means of Surber sampler (frame area 30x30 cm). A total of 65 genera from 38 families and 11 orders were found in the river. The results showed that based on diversity index, Lincoln Quality Index (LQI), Family Biotic Index (FBI), and Stream Invertebrate Grade Number Average Level 2 (SIGNAL 2), stations located within national park were ecologically better than those outside national park. Rivers with well-preserved riverside vegetation, as in the national park area have greater ecological status.

  19. Permafrost thaw and intense thermokarst activity decreases abundance of stream benthic macroinvertebrates.

    Science.gov (United States)

    Chin, Krista S; Lento, Jennifer; Culp, Joseph M; Lacelle, Denis; Kokelj, Steven V

    2016-08-01

    Intensification of permafrost thaw has increased the frequency and magnitude of large permafrost slope disturbances (mega slumps) in glaciated terrain of northwestern Canada. Individual thermokarst disturbances up to 40 ha in area have made large volumes of previously frozen sediments available for leaching and transport to adjacent streams, significantly increasing sediment and solute loads in these systems. To test the effects of this climate-sensitive disturbance regime on the ecology of Arctic streams, we explored the relationship between physical and chemical variables and benthic macroinvertebrate communities in disturbed and undisturbed stream reaches in the Peel Plateau, Northwest Territories, Canada. Highly disturbed and undisturbed stream reaches differed with respect to taxonomic composition and invertebrate abundance. Minimally disturbed reaches were not differentiated by these variables but rather were distributed along a disturbance gradient between highly disturbed and undisturbed sites. In particular, there was evidence of a strong negative relationship between macroinvertebrate abundance and total suspended solids, and a positive relationship between abundance and the distance from the disturbance. Increases in both sediments and nutrients appear to be the proximate cause of community differences in highly disturbed streams. Declines in macroinvertebrate abundance in response to slump activity have implications for the food webs of these systems, potentially leading to negative impacts on higher trophic levels, such as fish. Furthermore, the disturbance impacts on stream health can be expected to intensify as climate change increases the frequency and magnitude of thermokarst. © 2016 John Wiley & Sons Ltd.

  20. Trophic relationships between macroinvertebrates and fish in a pampean lowland stream (Argentina

    Directory of Open Access Journals (Sweden)

    María V. López van Oosterom

    2013-03-01

    Full Text Available The diet and trophic relationships between the macroinvertebrates Phyllogomphoides joaquini Rodrigues Capítulo, 1992 and Coenagrionidae (Odonata, Chironomidae (Diptera, Diplodon delodontus (Lamarck, 1919 (Bivalvia: Hyriidae, and Pomacea canaliculata (Lamarck, 1822 (Gastropoda: Ampulariidae and the fishes Pimelodella laticeps Eigenmann, 1917 (Heptapteridae and Bryconamericus iheringii (Boulenger, 1887 (Characidae in a temperate lowland lotic system in Argentina were assessed on the basis of gut contents and stable-isotope analyses. The feeding strategies were analyzed by the AMUNDSEN method. Relative food items contribution for the taxa studied indicated a generalist-type trophic strategy. In macroinvertebrates, in general, the values of stable isotope confirmed the result of the analysis of gut contents. With the fish, stable-isotope analysis demonstrated that both species are predators, although B. iheringii exhibited a more omnivorous behaviour. These feeding studies allowed us to determine the trophic relationships among taxa studied. Detritus and diatoms were a principal source of food for all the macroinvertebrates studied. In La Choza stream the particulate organic matter is a major no limited food resource, has a significant influence upon the community.

  1. How are macroinvertebrates of slow flowing lotic systems directly affected by suspended and deposited sediments?

    Energy Technology Data Exchange (ETDEWEB)

    Kefford, Ben J., E-mail: ben.kefford@rmit.edu.a [Biotechnology and Environmental Biology, School of Applied Sciences, RMIT University, PO Box 71, Bundoora, Victoria 3083 (Australia); Zalizniak, Liliana [Biotechnology and Environmental Biology, School of Applied Sciences, RMIT University, PO Box 71, Bundoora, Victoria 3083 (Australia); Dunlop, Jason E. [Department of Environment and Resource Management (DERM), 120 Meiers Rd, Indooroopilly, Queensland 4068 (Australia); Smart Water Research Facility, Griffith University, Queensland (Australia); Nugegoda, Dayanthi [Biotechnology and Environmental Biology, School of Applied Sciences, RMIT University, PO Box 71, Bundoora, Victoria 3083 (Australia); Choy, Satish C. [Department of Environment and Resource Management (DERM), 120 Meiers Rd, Indooroopilly, Queensland 4068 (Australia)

    2010-02-15

    The effects of suspended and deposited sediments on the macroinvertebrates are well documented in upland streams but not in slower flowing lowland rivers. Using species found in lowland lotic environments, we experimentally evaluate mechanisms for sediments to affect macroinvertebrates, and in one experiment whether salinity alters the effect of suspended sediments. Suspended kaolin clay reduced feeding of Ischnura heterosticta (Odonata: Coenagrionidae) at high turbidity (1000-1500 NTU) but had no effects on feeding of Hemianax papuensis (Odonata: Aeshnidae) and Micronecta australiensis (Hemiptera: Corixidae). In freshwater (0.1 mS/cm), survival of Ischnura aurora was poor in clear water, but improved with suspended kaolin. Growth and feeding of I. aurora were unaffected by suspended sediments and salinity. Burial (1-5 mm) of eggs with kaolin or sand reduced hatching in Physa acuta (Gastropoda: Physidae), Gyraulus tasmanica (Gastropoda: Planorbidae) and Chironomus cloacalis (Diptera: Chironomidae). Settling sediments may pose greater risk to lowland lotic invertebrates than suspended sediments. - Sediment deposition may be more directly detrimental to macroinvertebrates of lowland rivers than suspended sediments.

  2. Community structure of benthic macroinvertebrates inhabiting a highly stratified Mediterranean estuary

    Directory of Open Access Journals (Sweden)

    Alfonso Nebra

    2011-04-01

    Full Text Available The community composition and spatial distribution of benthic macroinvertebrates were studied along the Ebro estuary, a highly stratified estuary located in the NE Iberian Peninsula. During the last decade the oligotrophication process occurring in the lower Ebro River and its estuary has allowed a complex benthic macroinvertebrate community to become established; these results contrast with the poor community found there in the early nineties. A total of 214 taxa were identified, and polychaetes dominated the community both in abundance and species richness. The results showed spatial differences in the structure and composition of macroinvertebrates, which suggests that there are two distinct communities along the estuary. Each community was found in a specific stretch (upper and lower estuary in function of the presence of the salt wedge. The macrobenthos of the upper estuary was dominated by freshwater taxa, but some euryhaline species were also found. The lower estuary showed a marine community typical of shallow Mediterranean environments. The transition between these two communities fits an ecotone model. The highest abundances, richness and diversities were recorded at the lower estuarine stations, especially those closer to the river mouth, whereas the lowest values corresponded to the stations adjacent to the tip of the salt wedge.

  3. Effects of logging on macroinvertebrates in streams with and without buffer strips

    Energy Technology Data Exchange (ETDEWEB)

    Newbold, J D; Erman, D C; Roby, K B

    1980-01-01

    The impact of logging with and without buffer strip protection on stream macroinvertebrates was examined through comparisons of community structure in commercially logged and control watersheds throughout northern California. A nonparametric test of community dissimilarities within matched blocks of two control and one or two treated stations showed significant (P < 0.05) logging effects on unprotected streams when Euclidean distance and mutual information were used as dissimilarity indices, but not when chord distance was used. Shannon diversity in unprotected streams was lower (P < 0.01) than in control (unlogged) streams; densities of total macroinvertebrate fauna and of Chironomidae, Baetis, and Nemoura were higher in unprotected streams than in controls (P <0.05). Streams with narrow buffer strips (<30 m) showed significant effects by the Euclidean distance test, but diversity varied widely and was not significantly different from that in either unprotected or control streams than in controls (P < 0.05). Macroinvertebrate communities in streams with wide buffers (greater than or equal to 30m) could not be distinguished from those of controls by either Euclidean distance or diversity; however, diversity in wide-buffered streams was significantly greater than in streams without buffer strips, indicating effective protection from logging effects.

  4. Here Comes the Sun ... and I Say, "It' an Assemblage"

    Science.gov (United States)

    Skophammer, Karen

    2011-01-01

    In this article, the author discusses how she combines science lesson with a hands-on art project. She used the wonderfully creative suns shown on the Sunday edition of "The CBS Morning Show" to give the students fodder for thought. She describes how to create an assemblage. An assemblage is like a collage, but it moves past the two-dimensional…

  5. Effects of geomorphology, habitat, and spatial location on fish assemblages in a watershed in Ohio, USA.

    Science.gov (United States)

    D'Ambrosio, Jessica L; Williams, Lance R; Witter, Jonathan D; Ward, Andy

    2009-01-01

    In this paper, we evaluate relationships between in-stream habitat, water chemistry, spatial distribution within a predominantly agricultural Midwestern watershed and geomorphic features and fish assemblage attributes and abundances. Our specific objectives were to: (1) identify and quantify key environmental variables at reach and system wide (watershed) scales; and (2) evaluate the relative influence of those environmental factors in structuring and explaining fish assemblage attributes at reach scales to help prioritize stream monitoring efforts and better incorporate all factors that influence aquatic biology in watershed management programs. The original combined data set consisted of 31 variables measured at 32 sites, which was reduced to 9 variables through correlation and linear regression analysis: stream order, percent wooded riparian zone, drainage area, in-stream cover quality, substrate quality, gradient, cross-sectional area, width of the flood prone area, and average substrate size. Canonical correspondence analysis (CCA) and variance partitioning were used to relate environmental variables to fish species abundance and assemblage attributes. Fish assemblages and abundances were explained best by stream size, gradient, substrate size and quality, and percent wooded riparian zone. Further data are needed to investigate why water chemistry variables had insignificant relationships with IBI scores. Results suggest that more quantifiable variables and consideration of spatial location of a stream reach within a watershed system should be standard data incorporated into stream monitoring programs to identify impairments that, while biologically limiting, are not fully captured or elucidated using current bioassessment methods.

  6. Diversity and abundance of invertebrate epifaunal assemblages associated with gorgonians are driven by colony attributes

    KAUST Repository

    Curdia, Joao

    2015-03-20

    The present study aimed to explicitly quantify the link between the attributes of shallow-water gorgonian colonies (Octocorallia: Alcyonacea) and the ecological patterns of associated non-colonial epifaunal invertebrates. Based on multiple regression analysis, we tested the contribution of several attributes (colony height, width, and area, fractal dimension as a measure of colony complexity, lacunarity as a measure of the heterogeneity, and “colonial” epibiont cover) to abundance and taxonomic richness of associated assemblages. The results highlight the variation in the response of epifaunal assemblages to the gorgonian colony characteristics. The nature and intensity of the relationships were gorgonian species-dependent and varied from one taxonomic group to another. For both gorgonian species analyzed, the strongest predictor of species richness and abundance of the epifaunal assemblages was “colonial” epibiont cover, possibly due to a trophic effect (direct or indirect enhancement of food availability) combined with the surface available for colonization (species–area effect). Although structural complexity is usually indicated as the main driver for rich and abundant coral-associated assemblages, no significant relationship was observed between fractal dimension and the community descriptors; lacunarity, which reflects the sizes of the inter-branch spaces, was only linked to taxonomic richness in the assemblages associated with Leptogorgia lusitanica. The validity of the paradigm that structural complexity enhances biodiversity may be scale-dependent. In the case of gorgonians, the effect of complexity at the “garden” level may be more relevant than at the individual colony level. This reinforces the need for the conservation of gorgonian aggregation areas as a whole in order to preserve host diversity and size structure. © 2015 Springer-Verlag Berlin Heidelberg

  7. Meiofaunal assemblages associated with native and non-indigenous macroalgae

    Science.gov (United States)

    Veiga, Puri; Sousa-Pinto, Isabel; Rubal, Marcos

    2016-07-01

    Meiofauna is a useful tool to detect effects of different disturbances; however, its relevance in the frame of biological invasions has been almost fully neglected. Meiofaunal assemblages associated with the invasive macroalga Sargassum muticum were studied and compared with those associated with two native macroalgae (Bifurcaria bifurcata and Chondrus crispus). We used a linear mixed model to determine the influence of habitat size (i.e. macroalgal biomass) in shaping meiofaunal assemblages. Results showed that habitat size (i.e. macroalgal biomass) shaped meiofaunal assemblages influencing its abundance, richness and structure. However, the identity of macroalga (i.e. species) appears also to play a significant role, particularly the differences of complexity among the studied species may shape their meiofaunal assemblages. Finally, the invasive macroalga appears to influence positively species richness. Our results highlight the need of including different faunal components to achieve a comprehensive knowledge on effects of invasive macroalgae and that meiofaunal assemblages may be a valuable tool to examine them.

  8. A comparison of different biotic indices based on benthic macro-invertebrates in italian lakes

    Directory of Open Access Journals (Sweden)

    Laura MARZIALI

    2011-02-01

    Full Text Available Benthic macroinvertebrates samples were taken from Italian lakes with different geological, morphological and chemical characteristics. Thirty-two lowland small and large lakes sampled using a grab in soft substrate were selected to develop biotic indices. Diversity indices based on species numbers - abundances and indices using species sensitivity values were compared. The lakes selected were all situated in the Alpine Ecoregion below 800 m a.s.l. and had similar chemical composition but different levels of anthropogenic pressure. Lakes with data available in different years were included as separate lakes in the analysis; littoralsublittoral samples of large lakes were also separated from profundal samples yielding a total of 41 sites for analysis. Seven different biotic indices were compared: (1 Shannon diversity index (H, (2 weighted Shannon diversity index (Hw including in the calculation a sensitivity value assigned to each species, (3 a benthic quality index based on means of three different environmental variables, measuring trophic status, weighted by species abundances (BQITS, (4 an index based on weighted means using a larger set of environmental variables (BQIENV, (5 a modified BQITS, which included both species numbers and total abundance of individuals (BQIES, (6 an index calculated according to a rarefaction method (ES, (7 an index considering indicator species based on experts judgment (BQIEJ. The indices were compared with a trophic status index (TSI constructed by joining three environmental variables: O2% saturation in the hypolimnion during summer stratification, total phosphorous and transparency during full circulation. Comparisons were also made with another environmental stress index (ENI constructed on a larger number of variables. All the biotic indices had significant correlations with both TSI and ENI. BQIES, WFD compliant and well correlated with TSI and ENI, was selected to tentatively assign the investigated lakes

  9. The River Gelså restoration revisited: Habitat specific assemblages and persistence of the macroinvertebrate community over an 11-year period

    DEFF Research Database (Denmark)

    Friberg, Nikolai; Baattrup-Pedersen, Annette; Kristensen, Esben Astrup

    2014-01-01

    The study was undertaken on the River Gelså, Denmark, where a 1.8 km meandering course was estab-lished in 1989 to replace a channelized river reach. This restoration project was the first of its kind inDenmark and has the longest time-series of post-intervention data of any restoration project c...

  10. The response of benthic macroinvertebrate and fish assemblages to human impact along the lower stretch of the rivers Morava and Dyje (Danube basin, Czech Republic)

    Czech Academy of Sciences Publication Activity Database

    Adámek, Zdeněk; Zahrádková, S.; Jurajda, Pavel; Bernardová, I.; Jurajdová, Zdenka; Janáč, Michal; Němejcová, D.

    2013-01-01

    Roč. 71, č. 3 (2013), s. 93-115 ISSN 1330-061X R&D Projects: GA ČR GBP505/12/G112 Institutional support: RVO:68081766 Keywords : Macrozoobenthos * Fish * Diversity * River pollution * River regulation * Joint Danube Survey Subject RIV: EG - Zoology http://ribarstvo.agr.hr/volumes.php?lang=en&search=Article%3A656

  11. Biotic diversity of benthic macroinvertebrates at contrasting glacier-fed systems in Patagonia Mountains: The role of environmental heterogeneity facing global warming.

    Science.gov (United States)

    Miserendino, María Laura; Brand, Cecilia; Epele, Luis B; Di Prinzio, Cecilia Y; Omad, Guillermo H; Archangelsky, Miguel; Martínez, Oscar; Kutschker, Adriana M

    2018-05-01

    Patagonia is by far the largest glacierized area in South America. However, little is known about ecology, functioning and biodiversity of glacier-fed streams facing global warming. We investigated changes in environmental features and macroinvertebrate communities along a longitudinal gradient of glacier influence of two Patagonian systems that differ in glacier cover magnitude and the spatial sequence of lotic and lentic phases. Both glaciers, Torrecillas (~5.5km 2 , Torrecillas system) and Cónico (~0.44km 2 , Baggilt system), are retreating. Longitudinal distribution of benthic invertebrates partially fitted to predictions for glacierized temperate systems, with Diamesinae spp. dominating at closest sites to the Cónico, and Orthocladiinae increasing downstream, but patterns were unclear at Torrecillas. Generalized Linear Model identified chlorophyll a and conductivity as having significant effect on richness and density respectively at Torrecillas; detritus biomass and gravel influenced species richness, and boulder percentage and water temperature affected density, at Baggilt. Canonical Correspondence Analyses integrating benthic biota and environmental variables revealed that a higher environmental heterogeneity at Baggilt, related with spatial dimension (unshaded/shaded reaches, wetland reaches), local resources (detritus, bryophytes) and temperature, probably explained the unexpected high richness in benthic assemblages (67 taxa). Environmental conditions imposed by the lake outlet (proglacial) at Torrecillas resulted in a less diverse community (31 taxa). Finally our results suggest that these isolated, small glacier-fed streams typical of the Patagonian landscape appear highly vulnerable to global warming. Endemic elements could disappear at upper segments being replaced by other species common at rhithral environments, which might increase local diversity (alfa diversity) but decrease regional diversity (gamma diversity). From an ecosystem perspective

  12. Effects of sediment quality on macroinvertebrates in the Sunraysia region of the Murray-Darling Rivers, Australia

    Energy Technology Data Exchange (ETDEWEB)

    Sharley, David J. [Centre for Environmental Stress and Adaptation Research-Hoffmann Laboratory, Zoology Department, University of Melbourne, Level 2, Bio 21 Institute, 30 Flemington Road, Parkville, Victoria 3010 (Australia)], E-mail: sharleyd@unimelb.edu.au; Hoffmann, Ary A. [Centre for Environmental Stress and Adaptation Research-Hoffmann Laboratory, Zoology Department, University of Melbourne, Level 2, Bio 21 Institute, 30 Flemington Road, Parkville, Victoria 3010 (Australia); Pettigrove, Vincent [Research and Technology, Melbourne Water, PO Box 4342, Melbourne, Victoria 3001 (Australia)

    2008-12-15

    A field-based microcosm approach was tested to identify deterioration of sediment quality in waterways using freshwater macroinvertebrates. The method can potentially identify the nature of contaminants based on species-specific responses. Sediments were collected from the Murray and Darling Rivers and irrigation drains within the Sunraysia region of south-eastern Australia and compared to non-polluted reference sediment. Clean sediments were also spiked with fertiliser to test whether nutrients affected the aquatic fauna. Seven of the eight sediments from the Sunraysia region had a negative impact on the macroinvertebrates, in particular sediment from the Darling River, which supported an impoverished fauna. Three species of chironomid showed varied responses to sediment quality and, although it was hypothesised that nutrients may have impacted on the macroinvertebrate fauna, the results suggest that other pollutants are also involved. The field-based microcosm method proved effective for determining the impact of sediment quality on indigenous macroinvertebrates. - Sediment quality effects on freshwater macroinvertebrates are isolated.

  13. Effects of sediment quality on macroinvertebrates in the Sunraysia region of the Murray-Darling Rivers, Australia

    International Nuclear Information System (INIS)

    Sharley, David J.; Hoffmann, Ary A.; Pettigrove, Vincent

    2008-01-01

    A field-based microcosm approach was tested to identify deterioration of sediment quality in waterways using freshwater macroinvertebrates. The method can potentially identify the nature of contaminants based on species-specific responses. Sediments were collected from the Murray and Darling Rivers and irrigation drains within the Sunraysia region of south-eastern Australia and compared to non-polluted reference sediment. Clean sediments were also spiked with fertiliser to test whether nutrients affected the aquatic fauna. Seven of the eight sediments from the Sunraysia region had a negative impact on the macroinvertebrates, in particular sediment from the Darling River, which supported an impoverished fauna. Three species of chironomid showed varied responses to sediment quality and, although it was hypothesised that nutrients may have impacted on the macroinvertebrate fauna, the results suggest that other pollutants are also involved. The field-based microcosm method proved effective for determining the impact of sediment quality on indigenous macroinvertebrates. - Sediment quality effects on freshwater macroinvertebrates are isolated

  14. No correlation between the diversity and productivity of assemblages: evidence from the phytophage and predator assemblages in various cotton agroecosystems.

    Science.gov (United States)

    Gao, Feng; Men, XingYuan; Ge, Feng

    2014-09-01

    Biodiversity research has shown that primary productivity increases with plant species number, especially in many experimental grassland systems. Here, we assessed the correlation between productivity and diversity of phytophages and natural enemy assemblages associated with planting date and intercropping in four cotton agroecosystems. Twenty-one pairs of data were used to determine Pearson correlations between species richness, total number of individuals, diversity indices and productivity for each assemblage every five days from 5 June to 15 September 2012. At the same trophic level, the productivity exhibited a significant positive correlation with species richness of the phytophage or predator assemblage. A significant correlation was found between productivity and total number of individuals in most cotton fields. However, no significant correlations were observed between productivity and diversity indices (including indices of energy flow diversity and numerical diversity) in most cotton fields for either the phytophage or the predator assemblages. Species richness of phytophage assemblage and total individual numbers were significantly correlated with primary productivity. Also, species richness of natural enemy assemblage and total number of individuals correlated with phytophage assemblage productivity. A negative but not significant correlation occurred between the indices of numerical diversity and energy flow diversity and lower trophic-level productivity in the cotton-phytophage and phytophage-predator assemblages for most intercropped cotton agroecosystems. Our results clearly showed that there were no correlations between diversity indices and productivity within the same or lower trophic levels within the phytophage and predator assemblages in cotton agroecosystems, and inter-cropped cotton fields had a stronger ability to support the natural enemy assemblage and potentially to reduce phytophages.

  15. The response of chironomid assemblages to mineral richness gradient in the Western Carpathian helocrenes

    Directory of Open Access Journals (Sweden)

    Vít Syrovátka

    2012-10-01

    Full Text Available Chironomid assemblages of helocrene springs were investigated in the Western Carpathians in order to identify potential effect of water mineral richness on the taxonomic structure of the assemblages. A complex gradient considering water chemistry and substratum was used as a measure of basicity (mineral richness. Taxonomic structure, total abundance and abundance of most frequent taxa were related to this gradient with regards to two contrasting habitats: trickle (A and water-loged soil with standing water (B. The variance in chironomid assemblage attributable to basicity was estimated and tested via PERMANOVA as well as the possible effect of the other environmental variables. The response of individual taxa was examined using GAM. The results indicate a strong relationship between basicity and substratum characteristics, with coarser mineral substrata at basic and high amount of organic matter at acidic conditions. Although water chemistry was correlated with and inseparable from these substratum properties, it could not be substituted with them, as they discriminated well only between acidic and basic springs, but did not follow the basicity gradient in either acidic or basic group of springs. Chironomid assemblage showed a strong and systematic response to the complex gradient of mineral richness, which explained the largest portion of variance in both the habitat A and B faunal data and was projected on the first axes of both NMDS ordinations. The assemblage response could be documented by the preference of several taxa for particular mineral richness conditions, while the number of taxa seemed to be highest in the middle of the basicity gradient. As only 17 samples were analysed so far, the results are considered preliminary and, hopefully, more confident results will be available in near future.doi: 10.5324/fn.v31i0.1403.Published online: 17 October 2012.

  16. Riverine Landscape Patch Heterogeneity Drives Riparian Ant Assemblages in the Scioto River Basin, USA.

    Directory of Open Access Journals (Sweden)

    Paradzayi Tagwireyi

    Full Text Available Although the principles of landscape ecology are increasingly extended to include riverine landscapes, explicit applications are few. We investigated associations between patch heterogeneity and riparian ant assemblages at 12 riverine landscapes of the Scioto River, Ohio, USA, that represent urban/developed, agricultural, and mixed (primarily forested, but also wetland, grassland/fallow, and exurban land-use settings. Using remotely-sensed and ground-collected data, we delineated riverine landscape patch types (crop, grass/herbaceous, gravel, lawn, mudflat, open water, shrub, swamp, and woody vegetation, computed patch metrics (area, density, edge, richness, and shape, and conducted coordinated sampling of surface-active Formicidae assemblages. Ant density and species richness was lower in agricultural riverine landscapes than at mixed or developed reaches (measured using S [total number of species], but not using Menhinick's Index [DM], whereas ant diversity (using the Berger-Park Index [DBP] was highest in agricultural reaches. We found no differences in ant density, richness, or diversity among internal riverine landscape patches. However, certain characteristics of patches influenced ant communities. Patch shape and density were significant predictors of richness (S: R2 = 0.72; DM: R2=0.57. Patch area, edge, and shape emerged as important predictors of DBP (R2 = 0.62 whereas patch area, edge, and density were strongly related to ant density (R2 = 0.65. Non-metric multidimensional scaling and analysis of similarities distinguished ant assemblage composition in grass and swamp patches from crop, gravel, lawn, and shrub as well as ant assemblages in woody vegetation patches from crop, lawn, and gravel (stress = 0.18, R2 = 0.64. These findings lend insight into the utility of landscape ecology to river science by providing evidence that spatial habitat patterns within riverine landscapes can influence assemblage characteristics of riparian

  17. The definition of species richness used by species sensitivity distributions approximates observed effects of salinity on stream macroinvertebrates

    Energy Technology Data Exchange (ETDEWEB)

    Kefford, Ben J., E-mail: ben.kefford@uts.edu.a [School of Applied Sciences, RMIT University, Victoria (Australia); Centre for Environmental Sustainability, Department of Environmental Science, University of Technology Sydney, New South Wales (Australia); Marchant, Richard [Department of Entomology, Museum of Victoria, Victoria (Australia); Schaefer, Ralf B. [School of Applied Sciences, RMIT University, Victoria (Australia); Metzeling, Leon [EPA Victoria, Macleod, Victoria (Australia); Dunlop, Jason E. [Department of Environment and Resource Management, Indooroopilly, Queensland (Australia); National Research Centre for Environmental Toxicology, University of Queensland, Coopers Plains, Queensland (Australia); Choy, Satish C. [Department of Environment and Resource Management, Indooroopilly, Queensland (Australia); Goonan, Peter [South Australia Environment Protection Authority, Adelaide, South Australia (Australia)

    2011-01-15

    The risk of chemicals for ecological communities is often forecast with species sensitivity distributions (SSDs) which are used to predict the concentration which will protect p% of species (PC{sub p} value). However, at the PC{sub p} value, species richness in nature would not necessary be p% less than at uncontaminated sites. The definition of species richness inherent to SSDs (contaminant category richness) contrasts with species richness typically measured in most field studies (point richness). We determine, for salinity in eastern Australia, whether these definitions of stream macroinvertebrate species richness are commensurable. There were strong relationships (r{sup 2} {>=} 0.87) between mean point species, family and Ephemeroptera, Trichoptera and Plecoptera species richness and their respective contamination category richness. Despite differences in the definition of richness used by SSDs and field biomonitoring, their results in terms of relative species loss from salinity in south-east Australia are similar. We conclude that in our system both definitions are commensurable. - Definitions of species richness inherit in SSDs and biomonitoring are for salinity in south-east Australia commensurable.

  18. The definition of species richness used by species sensitivity distributions approximates observed effects of salinity on stream macroinvertebrates

    International Nuclear Information System (INIS)

    Kefford, Ben J.; Marchant, Richard; Schaefer, Ralf B.; Metzeling, Leon; Dunlop, Jason E.; Choy, Satish C.; Goonan, Peter

    2011-01-01

    The risk of chemicals for ecological communities is often forecast with species sensitivity distributions (SSDs) which are used to predict the concentration which will protect p% of species (PC p value). However, at the PC p value, species richness in nature would not necessary be p% less than at uncontaminated sites. The definition of species richness inherent to SSDs (contaminant category richness) contrasts with species richness typically measured in most field studies (point richness). We determine, for salinity in eastern Australia, whether these definitions of stream macroinvertebrate species richness are commensurable. There were strong relationships (r 2 ≥ 0.87) between mean point species, family and Ephemeroptera, Trichoptera and Plecoptera species richness and their respective contamination category richness. Despite differences in the definition of richness used by SSDs and field biomonitoring, their results in terms of relative species loss from salinity in south-east Australia are similar. We conclude that in our system both definitions are commensurable. - Definitions of species richness inherit in SSDs and biomonitoring are for salinity in south-east Australia commensurable.

  19. Evaluation of Deposited Sediment and Macroinvertebrate Metrics Used to Quantify Biological Response to Excessive Sedimentation in Agricultural Streams

    Science.gov (United States)

    Sutherland, Andrew B.; Culp, Joseph M.; Benoy, Glenn A.

    2012-07-01

    The objective of this study was to evaluate which macroinvertebrate and deposited sediment metrics are best for determining effects of excessive sedimentation on stream integrity. Fifteen instream sediment metrics, with the strongest relationship to land cover, were compared to riffle macroinvertebrate metrics in streams ranging across a gradient of land disturbance. Six deposited sediment metrics were strongly related to the relative abundance of Ephemeroptera, Plecoptera and Trichoptera and six were strongly related to the modified family biotic index (MFBI). Few functional feeding groups and habit groups were significantly related to deposited sediment, and this may be related to the focus on riffle, rather than reach-wide macroinvertebrates, as reach-wide sediment metrics were more closely related to human land use. Our results suggest that the coarse-level deposited sediment metric, visual estimate of fines, and the coarse-level biological index, MFBI, may be useful in biomonitoring efforts aimed at determining the impact of anthropogenic sedimentation on stream biotic integrity.

  20. Global assemblages and structural models of International Relations

    DEFF Research Database (Denmark)

    Corry, Olaf

    2014-01-01

    -category of assemblages – those constructed as malleable and governable which I call ‘governance-objects’ – is central to structure in international relations. The chapter begins with standard definitions of what structures are – patterns of interaction between elements – and briefly covers the range of models currently...... used to simplify different structures. Next the chapter points to the blindness of most structural theories of IR to the role of assemblages in general and governance-objects in particular. Thirdly, the idea that a polity is constituted precisely by the assemblage of a governance...

  1. Changes of Benthic Macroinvertebrates in Thi Vai River and Cai Mep Estuaries Under Polluted Conditions with Industrial Wastewater

    Directory of Open Access Journals (Sweden)

    Huong Nguyen Thi Thanh

    2017-06-01

    Full Text Available The pollution on the Thi Vai River has been spreading out rapidly over the two lasted decades caused by the wastewater from the industrial parks in the left bank of Thi Vai River and Cai Mep Estuaries. The evaluation of the benthic macroinvertebrate changes was very necessary to identify the consequences of the industrial wastewater on water quality and aquatic ecosystem of Thi Vai River and Cai Mep Estuaries. In this study, the variables of benthic macroinvertebrates and water quality were investigated in Thi Vai River and Cai Mep Estuaries, Southern Vietnam. The monitoring data of benthic macroinvertebrates and water quality parameters covered the period from 1989 to 2015 at 6 sampling sites in Thi Vai River and Cai Mep Estuaries. The basic water quality parameters were also tested including pH, dissolved oxygen (DO, total nitrogen, and total phosphorus. The biodiversity indices of benthic macroinvertebrates were applied for water quality assessment. The results showed that pH ranged from 6.4 – 7.6 during the monitoring. The DO concentrations were in between 0.20 - 6.70 mg/L. The concentrations of total nitrogen and total phosphorous ranged from 0.03 - 5.70 mg/L 0.024 - 1.380 mg/L respectively. Macroinvertebrate community in the study area consisted of 36 species of polychaeta, gastropoda, bivalvia, and crustacea, of which, species of polychaeta were dominant in species number. The benthic macroinvertebartes density ranged from 0 - 2.746 individuals/m−1 with the main dominant species of Neanthes caudata, Prionospio malmgreni, Paraprionospio pinnata, Trichochaeta carica, Maldane sarsi, Capitella capitata, Terebellides stroemi, Euditylia polymorpha, Grandidierella lignorum, Apseudes vietnamensis. The biodiversity index values during the monitoring characterized for aquatic environmental conditions of mesotrophic to polytrophic. Besides, species richness positively correlated with DO, total nitrogen, and total phosphorus. The results

  2. Aquatic macroinvertebrates of Batalha river reservoir for water captation and supply of the city of Bauru, SP, Brazil

    Directory of Open Access Journals (Sweden)

    Diana Calcidoni Moreira

    2009-08-01

    Full Text Available In this study the composition and diversity of aquatic macroinvertebrates were evaluated in the reservoir of water captation of Batalha river for treatment and supplying of the city of Bauru. The samples were collected in dry (from June to August, 2005 and rainy (from December, 2005 to February, 2006 seasons. We analyzed and identified 840 organisms belonging to 8 taxa in dry season and 4 taxa in rainy season. The system presented low abundance and diversity of macroinvertebrates probably due to the water quality and its physical and chemical variations associated with rain events.

  3. THE INFLUENCE OF POST-FLOTATION TAILINGS POND “WARTOWICE” (LOWER SILESIA ON THE BIODIVERSITY OF MACROINVERTEBRATES

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    Justyna Rybak

    2013-10-01

    Full Text Available In this paper the biodiversity studies on macroinvertebrates were conducted in the area post-flotation tailings pond “Wartowice”, which poses a serious threat to the environment. The analysis of the biodiversity was done with two methods: the use of biodiversity indices along with taxonomic identification to family level and with the application of morphospecies method. Both were assessed concerning their usefulness. Macrofauna was sampled in a five sites characterized by different level of pollution. We found the dependence of macroinvertebrates structure on habitat type. Both methods, although not very accurate, were found suitable for the assessment of such disturbance type.

  4. Stream macroinvertebrate communities across a gradient of natural gas development in the Fayetteville Shale.

    Science.gov (United States)

    Johnson, Erica; Austin, Bradley J; Inlander, Ethan; Gallipeau, Cory; Evans-White, Michelle A; Entrekin, Sally

    2015-10-15

    Oil and gas extraction in shale plays expanded rapidly in the U.S. and is projected to expand globally in the coming decades. Arkansas has doubled the number of gas wells in the state since 2005 mostly by extracting gas from the Fayetteville Shale with activity concentrated in mixed pasture-deciduous forests. Concentrated well pads in close proximity to streams could have adverse effects on stream water quality and biota if sedimentation associated with developing infrastructure or contamination from fracturing fluid and waste occurs. Cumulative effects of gas activity and local habitat conditions on macroinvertebrate communities were investigated across a gradient of gas well activity (0.2-3.6 wells per km(2)) in ten stream catchments in spring 2010 and 2011. In 2010, macroinvertebrate density was positively related to well pad inverse flowpath distance from streams (r=0.84, pgas activity close to streams. However, stream water turbidity (r=0.69, p=0.02) and chlorophyll a (r=0.89, pgas well activities. In 2011, a year with record spring flooding, a different pattern emerged where mayfly density (p=0.74, p=0.01) and mayfly, stonefly, and caddisfly richness (r=0.78, p=0.008) increased in streams with greater well density and less silt cover. Hydrology and well pad placement in a catchment may interact to result in different relationships between biota and catchment activity between the two sample years. Our data show evidence of different macroinvertebrate communities expressed in catchments with different levels of gas activity that reinforce the need for more quantitative analyses of cumulative freshwater-effects from oil and gas development. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Response of benthic macroinvertebrate communities to highway construction in an Appalachian watershed

    Science.gov (United States)

    Hedrick, Lara B.; Welsh, S.A.; Anderson, James T.; Lin, L.-S.; Chen, Y.; Wei, X.

    2010-01-01

    Highway construction in mountainous areas can result in sedimentation of streams, negatively impacting stream habitat, water quality, and biotic communities. We assessed the impacts of construction of a segment of Corridor H, a four-lane highway, in the Lost River watershed, West Virginia, by monitoring benthic macroinvertebrate communities and water quality, before, during, and after highway construction and prior to highway use at upstream and downstream sites from 1997 through 2007. Data analysis of temporal impacts of highway construction followed a Before-After-Control-Impact (BACI) study design. Highway construction impacts included an increase in stream sedimentation during the construction phase. This was indicated by an increase in turbidity and total suspended solids. Benthic macroinvertebrate metrics indicated a community more tolerant during and after construction than in the period before construction. The percent of Chironomidae and the Hilsenhoff Biotic Index (HBI) increased, while percent of Ephemeroptera, Plecoptera, and Trichoptera (EPT) decreased. Our 10-year study addressed short-term impacts of highway construction and found that impacts were relatively minimal. A recovery of the number of EPT taxa collected after construction indicated that the benthic macroinvertebrate community may be recovering from impacts of highway construction. However, this study only addressed a period of 3 years before, 3 years during, and 4 years post construction. Inferences cannot be made concerning the long-term impacts of the highway, highway traffic, runoff, and other factors associated with highway use. Continual monitoring of the watershed is necessary to determine if the highway has a continual impact on stream habitat, water quality, and biotic integrity. ?? 2010 Springer Science+Business Media B.V.

  6. Long-Term Benthic Macroinvertebrate Community Monitoring to Assess Pollution Abatement Effectiveness

    Energy Technology Data Exchange (ETDEWEB)

    Smith, John G [ORNL; Brandt, Craig C [ORNL; Christensen, Sigurd W [ORNL

    2011-01-01

    The benthic macroinvertebrate community of East Fork Poplar Creek (EFPC) in East Tennessee was monitored for 18 years to evaluate the effectiveness of a water pollution control program implemented at a major United States (U.S.) Department of Energy facility. Several actions were implemented to reduce and control releases of pollutants into the headwaters of the stream. Four of the most significant actions were implemented during different time periods, which allowed assessment of each action. Macroinvertebrate samples were collected annually in April from three locations in EFPC (EFK24, EFK23, and EFK14) and two nearby reference streams from 1986 through 2003. Significant improvements occurred in the macroinvertebrate community at the headwater sites (EFK24 and EFK23) after implementation of each action, while changes detected 9 km further downstream (EFK14) could not be clearly attributed to any of the actions. Because the stream was impacted at its origin, invertebrate recolonization was primarily limited to aerial immigration, thus, recovery has been slow. As recovery progressed, abundances of small pollution-tolerant taxa (e.g., Orthocladiinae chironomids) decreased and longer lived taxa colonized (e.g., hydropsychid caddisflies, riffle beetles, Baetis). While assessments lasting three to four years may be long enough to detect a response to new pollution controls at highly impacted locations, more time may be needed to understand the full effects. Studies on the effectiveness of pollution controls can be improved if impacted and reference sites are selected to maximize spatial and temporal trending, and if a multidisciplinary approach is used to broadly assess environmental responses (e.g., water quality trends, invertebrate and fish community assessments, toxicity testing, etc.).

  7. Field experiments on responses of a freshwater, benthic macroinvertebrate community to vertebrate predators

    International Nuclear Information System (INIS)

    Thorp, J.H.; Bergey, E.A.

    1981-01-01

    The seasonal importance of vertebrate predators in potentially regulating the abundance and diversity of the benthic macroinvertebrates in the littoral zone of a soft-bottom reservoir that receives thermal effluent from a nuclear production reactor was examined. Thirty-six predator (fish and turtle) exclusion cages (4 m 2 ) were placed in shallow water at six locations along a thermal gradient in Par Pond, a 1100-ha cooling reservoir on the Savannah River Plant near Aiken, South Carolina, USA. An additional 36 control plots (4 m 2 ) were also set up. Cages were in place during three, 3-mo test periods beginning in September 1977. Estimates of benthic density, taxon richness, and distribution within functional groups (defined by feeding mechanism) were calculated for each test period. Effects of temperature on predator-prey relationships were also determined. Experimental results of this study suggest that vertebrate predation was not the fundamental parameter organizing the benthic macroinvertebrate community in the littoral zone of this reservoir. Neither taxon richness nor density of total macroinvertebrates was conclusively related to predator treatment. Relationships between predator treatment and community response (changes in density and taxon richness) were generally unaffected by either plot locality, temperature fluctuations from thermal effluent, or seasonal changes. When data from caged and control plots were pooled, however, both location and water temperature individually had direct impacts on the benthic community. From these results and other field studies it is hypothesized that individual species of keystone benthic predators do not occur in the littoral zone of freshwater lentic environments with soft bottoms

  8. Combining literature review, acoustic mapping and in situ observations: an overview of coralligenous assemblages in Liguria (NW Mediterranean Sea

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    Almudena Cánovas Molina

    2016-03-01

    Full Text Available A review and update of the existing knowledge on the coralligenous assemblages of Liguria (NW Italy was conducted as an essential step towards management measures for their conservation according to the EU Marine Strategy Framework Directive. By combining a literature review, acoustic mapping and in situ observations on a geographic information systems platform, we were able to assess the distribution and heterogeneity of coralligenous assemblages and the main pressures affecting them. The reliability of the literature was previously estimated using a dependability index. The coralligenous assemblages cover an area of 130.9 ha and range from 10 to 113 m depth. Twelve different biological facies (five of them not included in the EUNIS list were identified and four main geomorphotypes (plungingcliffs, paleocliffs, rockfalls and shoals were recognized. Incident light values influenced the distribution of four facies in Portofino promontory. Pressures were found on 33% of the coralligenous assemblages investigated, mainly due to fishing activities, mass mortality events, invasive species and occasional mucilaginous events. Our results showed a high spatial, geomorphological and biological heterogeneity of coralligenous assemblages in Liguria.

  9. Partitioning taxonomic diversity of aquatic insect assemblages ...

    Science.gov (United States)

    Biological diversity can be divided into: alpha (α, local), beta (β, difference in assemblage composition among locals), and gamma (γ, total diversity). We assessed the partitioning of taxonomic diversity of Ephemeroptera, Plecoptera and Trichoptera (EPT) and of functional feeding groups (FFG) in Neotropical Savanna (southeastern Brazilian Cerrado) streams. To do so, we considered three diversity components: stream site (α), among stream sites (β1), and among hydrologic units (β2). We also evaluated the association of EPT genera composition with heterogeneity in land use, instream physical habitat structure, and instream water quality variables. The percent of EPT taxonomic α diversity (20.7%) was lower than the β1 and β2 diversities (53.1% and 26.2%, respectively). The EPT FFG α diversity (26.5%) was lower than the β1 diversity (55.8%) and higher than the β2 (17.7%) diversity. The collector-gatherer FFG was predominant and had the greatest β diversity among stream sites (β1, 55.8%). Our findings support the need for implementing regional scale conservation strategies in the Cerrado biome, which has been degraded by anthropogenic activities. Using adaptations of the US EPA’s National Aquatic Resource Survey (NARS) designs and methods, Ferreira and colleagues examined the distribution of taxonomic and functional diversity of aquatic insects among basins, stream sites within basins, and within stream sample reaches. They sampled 160 low-order stre

  10. Geographical assemblages of European raptors and owls

    Science.gov (United States)

    López-López, Pascual; Benavent-Corai, José; García-Ripollés, Clara

    2008-09-01

    In this work we look for geographical structure patterns in European raptors (Order: Falconiformes) and owls (Order: Strigiformes). For this purpose we have conducted our research using freely available tools such as statistical software and databases. To perform the study, presence-absence data for the European raptors and owl species (Class Aves) were downloaded from the BirdLife International website. Using the freely available "pvclust" R-package, we applied similarity Jaccard index and cluster analysis in order to delineate biogeographical relationships for European countries. According to the cluster of similarity, we found that Europe is structured into two main geographical assemblages. The larger length branch separated two main groups: one containing Iceland, Greenland and the countries of central, northern and northwestern Europe, and the other group including the countries of eastern, southern and southwestern Europe. Both groups are divided into two main subgroups. According to our results, the European raptors and owls could be considered structured into four meta-communities well delimited by suture zones defined by Remington (1968) [Remington, C.L., 1968. Suture-zones of hybrid interaction between recently joined biotas. Evol. Biol. 2, 321-428]. Climatic oscillations during the Quaternary Ice Ages could explain at least in part the modern geographical distribution of the group.

  11. Distribution of macroinvertebrates on intertidal rocky shores in Gorgona Island, Colombia (Tropical Eastern Pacific

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    Edgardo Londoño-Cruz

    2014-02-01

    Full Text Available Organisms found on rocky shores must endure harsh environmental conditions during tidal changes but scientific studies on tropical rocky shores are scarce, particularly in Colombian shores. Here we describe the spatial distribution of macroinvertebrates associated to the intertidal rocky ecosystems of Gorgona Island, Colombia (Tropical Eastern Pacific. Sampling was carried out in four localities around the Island: La Ventana and La Camaronera (sampled during October 2010 and La Mancora and El Muelle (sampled during March 2011. Two methodologies were used: rapid ecological assessments for qualitative data and quadrats for quantitative data. The richness, abundance, diversity (Shannon-Wiener H’, and evenness (Pielou J’ of macroinvertebrates were determined for and compared between, using one way ANOVA, each locality and the three intertidal zones of La Ventana (see methods. One hundred twenty-one species of macroinvertebrates were found during the sampling period. In all localities, Mollusca was the richest and most abundant taxon (46% of the species and 59% of the individuals, followed by Crustacea (32% of the species and 33% of the individuals. The other groups accounted for the remaining 22% of the richness and 8% of the abundance. Several studies have demonstrated that mollusks and crustaceans are the richest and most abundant taxa in marine benthic communities. Most of the abundant species found were herbivores. The species composition varied among zones. The results of dominant species for each zone are consistent with the ones observed in other tropical rocky intertidal shores. All response variables showed a decreasing pattern from the low to the high intertidal (in La Ventana. Post-hoc results indicated that the high intertidal, the zone with the harshest environmental conditions, had significantly lower values than the other two zones for all response variables. Comparisons between the low intertidal zones of the different localities

  12. Seagrass habitat complexity and macroinvertebrate abundance in Lakshadweep coral reef lagoons, Arabian Sea

    Science.gov (United States)

    Ansari, Z. A.; Rivonker, C. U.; Ramani, P.; Parulekar, A. H.

    1991-09-01

    Macrofauna of seagrass community in the five Lakshadweep atolls were studied and compared. The associated epifaunal and infaunal taxa comprising nine major taxonomic groups, showed significant differences in the total number of individuals (1041 8411 m-2) among sites and habitats. The density of macrofauna was directly related to mean macrophytic biomass (405 895 g wet wt. m-2). The fauna was dominated by epifaunal polychaetes, amphipods and isopods in the vegetated areas. When compared with the density of nearby unvegetated areasleft( {bar x = 815{text{m }}^{ - 2} } right), seagrass meadows harbour a denser and richer macroinvertebrate assemblageleft( {bar x = 4023{text{m }}^{ - 2} } right).

  13. Mesohabitat mosaic in lowland braided rivers: Short-term variability of macroinvertebrate metacommunities

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    Gemma Burgazzi

    2017-04-01

    Full Text Available Braided rivers are among the most variable and dynamic riverine systems. Changes in these environments are sudden and frequent, driven by the high hydrological variability. They host high levels of local heterogeneity, with many different habitats in close proximity establishing a mosaic of patches. This provides the conditions for high levels of biodiversity, with strong community variability in particular among the different habitats at the stream-reach level. Nevertheless, these systems are still poorly studied and their complexity is often not taken into account in biomonitoring protocols. We applied mixed effects modelling, spatial ordination techniques and beta-diversity partitioning (into nestedness and turnover components with the aim of improving the knowledge of braided rivers, investigating: i the organization of macroinvertebrate communities among the different habitats of a river reach, and ii the temporal variability of this organization (both among seasons and during summer. We predicted a differentiation of macroinvertebrate communities between distinct habitats within rivers, with this differentiation increasing during the low-flow period. We carried out our study in four braided rivers and streams of the Po River basin (Northern Italy sampling three different kinds of mesohabitats (main channel, secondary channel and pool in eight stations during seven campaigns from June 2015 to April 2016. We found a high variability of taxa richness, abundance and community structure among mesohabitats, with marginal ones accounting for the greater part of macroinvertebrate diversity. Secondary channels resulted as being the habitat hosting greater taxa diversity, with 10 exclusive taxa. Surprisingly the mesohabitat communities differed greatly during the seasonal phase, whereas their dissimilarity decreased during summer. This could be explained considering the summer flow reduction as a homogenizing force, leading to a general loss of the

  14. Evidence for responses in water chemistry and macroinvertebrates in a strongly acidified mountain stream

    Czech Academy of Sciences Publication Activity Database

    Beneš, F.; Horecký, J.; Senoo, T.; Kamasová, L.; Lamačová, Anna; Tátosová, J.; Hardekopf, D. W.; Stuchlík, Evžen

    2017-01-01

    Roč. 72, č. 9 (2017), s. 1049-1058 ISSN 0006-3088 R&D Projects: GA ČR(CZ) GA17-05935S; GA ČR(CZ) GA15-08124S Institutional support: RVO:86652079 ; RVO:60077344 Keywords : acidified mountain stream * macroinvertebrates * logging * hydrological patterns * recovery Subject RIV: EH - Ecology, Behaviour; EH - Ecology, Behaviour (BC-A) OBOR OECD: Environmental sciences (social aspects to be 5.7); Environmental sciences (social aspects to be 5.7) (BC-A) Impact factor: 0.759, year: 2016

  15. Climate mediates the effects of disturbance on ant assemblage structure

    Czech Academy of Sciences Publication Activity Database

    Gibb, H.; Sanders, N. J.; Dunn, R. R.; Watson, S.; Photakis, M.; Abril, S.; Andersen, A. N.; Angulo, E.; Armbrecht, I.; Arnan, X.; Baccaro, F. B.; Bishop, T. R.; Boulay, R.; Castracani, C.; Del Toro, I.; Delsinne, T.; Diaz, M.; Donoso, D. A.; Enríquez, M. L.; Fayle, Tom Maurice; Feener Jr., D. H.; Fitzpatrik, M. C.; Gómez, C.; Grasso, D. A.; Groc, S.; Heterick, B.; Hoffmann, B. D.; Lach, L.; Lattke, J.; Leponce, M.; Lessard, J.-P.; Longino, J.; Lucky, A.; Majer, J.; Menke, S. B.; Mezger, D.; Mori, A.; Munyai, T. C.; Paknia, O.; Pearce-Duvet, J.; Pfeiffer, M.; Philpott, S. M.; de Souza, J. L. P.; Tista, M.; Vasconcelos, H. L.; Vonshak, M.; Parr, C. L.

    2015-01-01

    Roč. 282, č. 1808 (2015), article number 20150418 ISSN 0962-8452 Institutional support: RVO:60077344 Keywords : assemblage structure * dominance * global warming Subject RIV: EH - Ecology, Behaviour Impact factor: 4.823, year: 2015

  16. Determinants of fish assemblage structure in Northwestern Great Plains streams

    Science.gov (United States)

    Mullen, J.A.; Bramblett, R.G.; Guy, C.S.; Zale, A.V.; Roberts, D.W.

    2011-01-01

    Prairie streams are known for their harsh and stochastic physical conditions, and the fish assemblages therein have been shown to be temporally variable. We assessed the spatial and temporal variation in fish assemblage structure in five intermittent, adventitious northwestern Great Plains streams representing a gradient of watershed areas. Fish assemblages and abiotic conditions varied more spatially than temporally. The most important variables explaining fish assemblage structure were longitudinal position and the proportion of fine substrates. The proportion of fine substrates increased proceeding upstream, approaching 100% in all five streams, and species richness declined upstream with increasing fine substrates. High levels of fine substrate in the upper reaches appeared to limit the distribution of obligate lithophilic fish species to reaches further downstream. Species richness and substrates were similar among all five streams at the lowermost and uppermost sites. However, in the middle reaches, species richness increased, the amount of fine substrate decreased, and connectivity increased as watershed area increased. Season and some dimensions of habitat (including thalweg depth, absolute distance to the main-stem river, and watershed size) were not essential in explaining the variation in fish assemblages. Fish species richness varied more temporally than overall fish assemblage structure did because common species were consistently abundant across seasons, whereas rare species were sometimes absent or perhaps not detected by sampling. The similarity in our results among five streams varying in watershed size and those from other studies supports the generalization that spatial variation exceeds temporal variation in the fish assemblages of prairie and warmwater streams. Furthermore, given longitudinal position, substrate, and stream size, general predictions regarding fish assemblage structure and function in prairie streams are possible. ?? American

  17. Global warming transforms coral reef assemblages.

    Science.gov (United States)

    Hughes, Terry P; Kerry, James T; Baird, Andrew H; Connolly, Sean R; Dietzel, Andreas; Eakin, C Mark; Heron, Scott F; Hoey, Andrew S; Hoogenboom, Mia O; Liu, Gang; McWilliam, Michael J; Pears, Rachel J; Pratchett, Morgan S; Skirving, William J; Stella, Jessica S; Torda, Gergely

    2018-04-01

    Global warming is rapidly emerging as a universal threat to ecological integrity and function, highlighting the urgent need for a better understanding of the impact of heat exposure on the resilience of ecosystems and the people who depend on them 1 . Here we show that in the aftermath of the record-breaking marine heatwave on the Great Barrier Reef in 2016 2 , corals began to die immediately on reefs where the accumulated heat exposure exceeded a critical threshold of degree heating weeks, which was 3-4 °C-weeks. After eight months, an exposure of 6 °C-weeks or more drove an unprecedented, regional-scale shift in the composition of coral assemblages, reflecting markedly divergent responses to heat stress by different taxa. Fast-growing staghorn and tabular corals suffered a catastrophic die-off, transforming the three-dimensionality and ecological functioning of 29% of the 3,863 reefs comprising the world's largest coral reef system. Our study bridges the gap between the theory and practice of assessing the risk of ecosystem collapse, under the emerging framework for the International Union for Conservation of Nature (IUCN) Red List of Ecosystems 3 , by rigorously defining both the initial and collapsed states, identifying the major driver of change, and establishing quantitative collapse thresholds. The increasing prevalence of post-bleaching mass mortality of corals represents a radical shift in the disturbance regimes of tropical reefs, both adding to and far exceeding the influence of recurrent cyclones and other local pulse events, presenting a fundamental challenge to the long-term future of these iconic ecosystems.

  18. Soil nematode assemblages as bioindicators of radiation impact in the Chernobyl Exclusion Zone.

    Science.gov (United States)

    Lecomte-Pradines, C; Bonzom, J-M; Della-Vedova, C; Beaugelin-Seiller, K; Villenave, C; Gaschak, S; Coppin, F; Dubourg, N; Maksimenko, A; Adam-Guillermin, C; Garnier-Laplace, J

    2014-08-15

    In radioecology, the need to understand the long-term ecological effects of radioactive contamination has been emphasised. This requires that the health of field populations is evaluated and linked to an accurate estimate of received radiological dose. The aim of the present study was to assess the effects of current radioactive contamination on nematode assemblages at sites affected by the fallout from the Chernobyl accident. First, we estimated the total dose rates (TDRs) absorbed by nematodes, from measured current soil activity concentrations, Dose Conversion Coefficients (DCCs, calculated using EDEN software) and soil-to-biota concentration ratios (from the ERICA tool database). The impact of current TDRs on nematode assemblages was then evaluated. Nematodes were collected in spring 2011 from 18 forest sites in the Chernobyl Exclusion Zone (CEZ) with external gamma dose rates, measured using radiophotoluminescent dosimeters, varying from 0.2 to 22 μGy h(-1). These values were one order of magnitude below the TDRs. A majority of bacterial-, plant-, and fungal-feeding nematodes and very few of the disturbance sensitive families were identified. No statistically significant association was observed between TDR values and nematode total abundance or the Shannon diversity index (H'). The Nematode Channel Ratio (which defines the relative abundance of bacterial- versus fungal-feeding nematodes) decreased significantly with increasing TDR, suggesting that radioactive contamination may influence nematode assemblages either directly or indirectly by modifying their food resources. A greater Maturity Index (MI), usually characterising better soil quality, was associated with higher pH and TDR values. These results suggest that in the CEZ, nematode assemblages from the forest sites were slightly impacted by chronic exposure at a predicted TDR of 200 μGy h(-1). This may be imputable to a dominant proportion of pollutant resistant nematodes in all sites. This might

  19. The Miocene carnivore assemblage of Greece

    Directory of Open Access Journals (Sweden)

    Koufos, G. D.

    2011-12-01

    Full Text Available The Miocene carnivore assemblage of Greece includes a great number of taxa, described in numerous articles since the first decades of the 19th Century. The present article is a revision of all these taxa, providing information about their history, localities, age, as well as their stratigraphic distribution and palaeoenvironment. The Early/Middle Miocene carnivore record of Greece is poor as the available fossiliferous sites and material are rare. However, the Late Miocene one is quite rich, including numerous taxa. The Miocene localities with carnivores and their age are given in a stratigraphic table covering the European Mammal zones from MN 4 to MN 13. The type locality, holotype, and some historical and morphological remarks are given for each taxon. Several carnivore taxa were erected from Greek material and new photos of their holotypes are given. The stratigraphic distribution of the Greek carnivore taxa indicates that they are covering the time span from ~19.0-5.3Ma. The majority of the Miocene taxa (Adcrocuta, Hyaenictitherium, Plioviverrops, Protictitherium, Ictitherium, Indarctos, Dinocrocuta, Promephitis disappeared at the end of Miocene. The composition of the Early/Middle Miocene carnivore assemblage of Greece includes mainly viverrids (Lophocyon, Euboictis, while the hyaenids, percrocutids, felids and mustelids are very few. On the contrary the Late Miocene assemblage is richer, including more subfamilies and species; the hyaenids and mustelids dominate, while the viverrids are absent. The Late Miocene carnivore guild structure is similar to that of the modern Serengeti, indicating a relatively open, savannah-like environment.

    La asociación de carnívoros miocenos de Grecia incluye un gran número de taxones, descritos en numerosos artículos desde las primeras décadas del siglo XIX. El presente artículo supone un esfuerzo de síntesis de todos estos taxones, suministrando información sobre su

  20. Macroinvertebrate response to acid mine drainage: community metrics and on-line behavioural toxicity bioassay

    International Nuclear Information System (INIS)

    Gerhardt, A.; Janssens de Bisthoven, L.; Soares, A.M.V.M.

    2004-01-01

    The hypothesis is tested that toxicity of acid mine drainage can be detected by a selection of existing macroinvertebrate community and bioindicator metrices supplemented by toxicity tests with the local mosquitofish Gambusia holbrooki Girard and the shrimp Atyaephyra desmaresti Millet. The behavioural responses of A. desmaresti to acid mine drainage were recorded in the Multispecies Freshwater Biomonitor[reg], based on behaviour and survival as parameters. Bioassessment methods were based on community diversity, structure, function, and bioindicators and supplemented by chemical analysis (temperature, pH, metals). The Biological Monitoring Working Party adapted for the Iberian Peninsula, the number of predators (Coleoptera, Hemiptera) and the number of Ephemeroptera and Trichoptera taxa differentiated the sites well. The on-line toxicity test revealed pH-dependent acute toxicity of the acid mine drainage for the shrimp (LC 50 -48 h: pH-AMD=5.8) and a pH- dependent decrease in locomotory activity with the lowest-observed-response-times (LORTs) within 5 h of exposure. Shrimp were more sensitive to acid mine drainage than fish (LC 50 -48 h: pH-AMD=4.9). A new multimetric index combining toxicity testing and bioassessment methods is proposed. - Toxicity of acid mine drainage was evaluated by macroinvertebrate bioassessment and a new on-line rapid behavioural toxicity test with Atyaephyra desmaresti (Crustacea)

  1. Macroinvertebrate response to acid mine drainage: community metrics and on-line behavioural toxicity bioassay

    Energy Technology Data Exchange (ETDEWEB)

    Gerhardt, A.; Janssens de Bisthoven, L.; Soares, A.M.V.M

    2004-07-01

    The hypothesis is tested that toxicity of acid mine drainage can be detected by a selection of existing macroinvertebrate community and bioindicator metrices supplemented by toxicity tests with the local mosquitofish Gambusia holbrooki Girard and the shrimp Atyaephyra desmaresti Millet. The behavioural responses of A. desmaresti to acid mine drainage were recorded in the Multispecies Freshwater Biomonitor[reg], based on behaviour and survival as parameters. Bioassessment methods were based on community diversity, structure, function, and bioindicators and supplemented by chemical analysis (temperature, pH, metals). The Biological Monitoring Working Party adapted for the Iberian Peninsula, the number of predators (Coleoptera, Hemiptera) and the number of Ephemeroptera and Trichoptera taxa differentiated the sites well. The on-line toxicity test revealed pH-dependent acute toxicity of the acid mine drainage for the shrimp (LC{sub 50}-48 h: pH-AMD=5.8) and a pH- dependent decrease in locomotory activity with the lowest-observed-response-times (LORTs) within 5 h of exposure. Shrimp were more sensitive to acid mine drainage than fish (LC{sub 50}-48 h: pH-AMD=4.9). A new multimetric index combining toxicity testing and bioassessment methods is proposed. - Toxicity of acid mine drainage was evaluated by macroinvertebrate bioassessment and a new on-line rapid behavioural toxicity test with Atyaephyra desmaresti (Crustacea)

  2. Impact of heated waters on water quality and macroinvertebrate community in the Narew River (Poland

    Directory of Open Access Journals (Sweden)

    Krolak Elzbieta

    2017-07-01

    Full Text Available The effect of heated waters from coal-burning power stations on the water parameters and the occurrence of macroinvertebrates depends on the individual characteristics of the river to which the heated waters are discharged. The objective of the study was to assess the impact of heated water from the Ostrołęka Power Station on selected water properties and the macroinvertebrate community in the Narew River. Samples were collected in years: 2013-2016 along two river stretches: upstream and downstream of the canal. The water temperature was higher and the oxygen concentrations were lower at the downstream sites compared to the upstream sites of the canal. The values of conductivity, concentrations of nitrates, phosphates, chlorides and calcium were similar at the sampling sites. A total of 33 families of macrozoobenthos were found. The numbers of families were positively correlated with the temperature and conductivity and negatively correlated with oxygen. The heated waters were found to have no effect on the Shannon-Wiener diversity index. The inflow of heated waters increased the percentage of Gammaridae, represented by species Dikerogammarus haemobaphes (Eichwald, 1841 and decreased the percentage of Chironomidae. The presence of the thermophilous bivalve Sinanodonta woodiana (Lea, 1934 was noted downstream of the canal.

  3. Assessment of benthic macroinvertebrates at Nile tilapia production using artificial substrate samplers

    Directory of Open Access Journals (Sweden)

    M. S. G. Moura e Silva

    Full Text Available Abstract Biomonitoring is a cheap and effective tool for evaluation of water quality, and infer on the balance of aquatic ecosystems. The benthic macroinvertebrates are bioindicators sensitive to environmental changes, and can assist in detecting and preventing impacts such as organic enrichment and imbalance in the food chain. We compared the structure of benthic communities on artificial substrate samplers located in places near and far from net cages for production of Nile tilapia (Oreochromis niloticus. Samplers were manufactured with nylon net, using substrates such as crushed stone, gravel, loofah and cattail leaves. Samples were collected after 30 days of colonization, rinsed and then the specimens were identified and quantified. The following metrics were calculated: richness of Operational Taxonomic Units, Margalef richness, abundance of individuals, Shannon index and evenness index. The macrobenthic community structure was strongly modified according to the proximity of the net cages. Metrics showed significant differences (p < 0.05 between near and distant sites, for both periods (dry and rainy seasons. The position of the samplers significantly affected the structure of macroinvertebrate community, as near sites showed higher values for the community metrics, such as richness and diversity. Near sites presented a larger number of individuals, observed both in the dry and rainy seasons, with a predominance of Chironomidae (Diptera in the dry season and Tubificidae (Oligochaeta in the rainy season.

  4. Mercury in fish and macroinvertebrates from New York's streams and rivers: A compendium of data sources

    Science.gov (United States)

    Riva-Murray, Karen; Burns, Douglas A.

    2016-01-01

    The U.S. Geological Survey has compiled a list of existing data sets, from selected sources, containing mercury (Hg) concentration data in fish and macroinvertebrate samples that were collected from flowing waters of New York State from 1970 through 2014. Data sets selected for inclusion in this report were limited to those that contain fish and (or) macroinvertebrate data that were collected across broad areas, cover relatively long time periods, and (or) were collected as part of a broader-scale (e.g. national) study or program. In addition, all data sets listed were collected, processed, and analyzed with documented methods, and contain critical sample information (e.g. fish species, fish size, Hg species) that is needed to analyze and interpret the reported Hg concentration data. Fourteen data sets, all from state or federal agencies, are listed in this report, along with selected descriptive information regarding each data source and data set contents. Together, these 14 data sets contain Hg and related data for more than 7,000 biological samples collected from more than 700 unique stream and river locations between 1970 and 2014.

  5. Pampean lizard assemblage from subtropical Brazil: a temporal analysis

    Directory of Open Access Journals (Sweden)

    Gisele R. Winck

    2011-12-01

    Full Text Available The increasing human occupation of natural environments is one of the greatest threats to biodiversity. To mitigate the negative anthropogenic effects, it is necessary to understand the characteristics of natural populations and the natural history of species. A study was conducted with an assemblage of lizards from a disturbed area of the Pampa biome, from February 2001 to January 2004. The assemblage showed a unimodal seasonal pattern, with the recruitment period occurring during the warmer months. The captures were seasonal for two of the three monitored years, and concentrated within warmer months. The minimum temperature explained the number of catches for the assemblage as a whole. However, when the species were analyzed individually, the temperature only explained the seasonal occurrence of Teius oculatus. The abundance of species was significantly different in the third year of study for Cercosaura schreibersii and Ophiodes striatus. This latter species was no longer registered in the study area from May 2003 until the end of the study. Therefore, O. striatus may be more sensitive to environmental changes, considering the events of change in vegetation during the study. With frequent and increasing environmental disturbances, it is necessary to take conservation measures and encourage the increase of knowledge on Pampean lizards.O crescimento da ocupação humana sobre ambientes naturais é uma das maiores ameaças à biodiversidade. Para amenizar os efeitos negativos antropogênicos, é necessário entender as características das populações naturais, e a história natural das espécies. Um estudo foi conduzido com uma assembeia de lagartos de uma área perturbada do Pampa, de fevereiro de 2002 a janeiro de 2004. A assembleia apresentou padrão sazonal unimodal, com recrutamento ocorrendo durante os meses mais quentes. As capturas foram sazonais durante dois dos três anos monitorados, e concentradas nos meses mais quentes. A

  6. Biodiversity assessment of benthic macroinvertebrates along a reservoir cascade in the lower São Francisco river (northeastern Brazil

    Directory of Open Access Journals (Sweden)

    M. Callisto

    Full Text Available In order to verify the cascade-system effect in benthic macroinvertebrate communities, and the implications for policy making and proposals for conservation and sustainable use of the lower portion of São Francisco river basin (Bahia State, Brazil, a three-reservoir cascade system including two stretches downstream were studied during dry (June, 1997 and rainy (March, 1998 periods. The dominant groups found were Mollusca (Melanoides tuberculata, Oligochaeta, and Chironomidae larvae. Low Shannon-Wiener and Pielou index values were found, but with no significant difference between the sampling periods. However, density and taxonomic richness were significantly different (t(0.05; 31 = -2.1945; p < 0.05; e t(0.05; 31 = -3.0600; p < 0.01 between the sampling periods, with a reduction in the number of taxaand macroinvertebrate abundance during the rainy period. An increasing gradient in benthic macroinvertebrate community structures was noted along the reservoir cascade from the first reservoir (Apolônio Sales, followed by a decrease downstream from the third reservoir of the system (Xingó. Despite the negative consequences of rapid proliferation of dams, which have caused widespread loss of freshwater habitats, the reservoir cascade system promoted an increase in benthic macroinvertebrate diversity, due to water-quality improvement along the system.

  7. Agricultural Rivers at Risk: Dredging Results in a Loss of Macroinvertebrates. Preliminary Observations from the Narew Catchment, Poland

    Directory of Open Access Journals (Sweden)

    Mateusz Grygoruk

    2015-08-01

    Full Text Available Ecosystem deterioration in small lowland agricultural rivers that results from river dredging entails a significant threat to the appropriate ecohydrological conditions of these water bodies, expressed as homogenization of habitats and loss of biodiversity. Our study was aimed at a comparison of abundance and taxonomic structure of bottom-dwelling macroinvertebrates in dredged and non-dredged stretches of small lowland rivers and tributaries of the middle Narew River, namely: Czaplinianka, Turośnianka, Dąb, and Ślina. The experimental setup was (1 to collect samples of the bottom material from the river stretches that either persisted in a non-modified state (dredging was not done there in the last few years or had been subjected to river dredging in the year of sampling; and (2 to analyze the abundance and taxonomic structure of macroinvertebrates in the collected samples. The study revealed that at the high level of statistical significance (from p = 0.025 to p = 0.001, the total abundance of riverbed macroinvertebrates in the dredged stretches of the rivers analyzed was approximately 70% lower than in non-dredged areas. We state that the dredging of small rivers in agricultural landscapes seriously affects their ecological status by negatively influencing the concentrations and species richness of benthic macroinvertebrates.

  8. LANDSCAPE INFLUENCES ON IN-STREAM BIOTIC INTEGRITY: USE OF MACROINVERTEBRATE METRICS TO IDENTIFY LANDSCAPE STRESSORS IN HEADWATER CATCHMENTS

    Science.gov (United States)

    The biotic integrity of streams is profoundly influenced by quantitative and qualitative features in the landscape of the surrounding catchment. In this study, aquatic macroinvertebrate metrics (e.g., relative abundance of Ephemeroptera, Trichoptera, and/or Plecoptera taxa, or t...

  9. Efficiency of Pollution Tolerance Index (PTI of macroinvertebrates in detecting aquatic pollution in an oxbow lake in India

    Directory of Open Access Journals (Sweden)

    Dipankar Ghosh

    2017-11-01

    Full Text Available This paper evaluates the efficiency of a macroinvertebrate-based Pollution Tolerance Index (PTI in detecting aquatic pollution in the Chhariganga oxbow lake in India. In this lake, calculated PTIs were compared with results from an array of physicochemical water and sediment parameters and to a macroinvertebrate diversity assessment conducted in parallel for the same lake. The obtained PTI values fell in a range (between 20 and 31 that are indicative of an absence of organic pollution according to the literature, and are normally reported for systems devoid of anthropogenic activity (for instance no monsoonal polluting jute retting activities. However, in the light of the results for the assessed water and sediment physicochemical parameters, and the support of diversity indexes of macroinvertebrates, using data from the same lake, it was possible to conclude that the obtained PTI values do not reflect the true pollution status of this oxbow lake. As PTI values and diversity indexes contradict each other in detecting pollution, it is advised to take both parameters into consideration when using macroinvertebrates to assess aquatic health.

  10. Relationships between soil properties and community structure of soil macroinvertebrates in oak-history forests along an acidic deposition gradient

    Energy Technology Data Exchange (ETDEWEB)

    Kuperman, R.G. [Argonne National Lab., IL (United States). Environmental Assessment Div.

    1996-02-01

    Soil macroinvertebrate communities were studied in ecologically analogous oak-hickory forests across a three-state atmospheric pollution gradient in Illinois, Indiana, and Ohio. The goal was to investigate changes in the community structure of soil fauna in study sites receiving different amounts of acidic deposition for several decades and the possible relationships between these changes and physico-chemical properties of soil. The study revealed significant differences in the numbers of soil animals among the three study sites. The sharply differentiated pattern of soil macroinvertebrate fauna seems closely linked to soil chemistry. Significant correlations of the abundance of soil macroinvertebrates with soil parameters suggest that their populations could have been affected by acidic deposition in the region. Abundance of total soil macroinvertebrates decreased with the increased cumulative loading of acidic deposition. Among the groups most sensitive to deposition were: earthworms gastropods, dipteran larvae, termites, and predatory beetles. The results of the study support the hypothesis that chronic long-term acidic deposition could aversely affect the soil decomposer community which could cause lower organic matter turnover rates leading to an increase in soil organic matter content in high deposition sites.

  11. Macroinvertebrate community structure and function along gradients of physical stream quality and pesticide contamination in Danish streams

    DEFF Research Database (Denmark)

    Rasmussen, Jes

    to stream are surface runoff and tile drainage giving rise to short pulses of acute contamination strongly coinciding with high levels of precipitation. Field studies indicate that macroinvertebrate community structure can be impacted by pesticides during spraying seasons in May and June, but also...

  12. Assessment of the ecological potential of mine-water treatment wetlands using a baseline survey of macroinvertebrate communities

    International Nuclear Information System (INIS)

    Batty, L.C.; Atkin, L.; Manning, D.A.C.

    2005-01-01

    A baseline survey of macroinvertebrate populations in two mine-water treatment wetlands, one treating a net acidic spoil heap discharge and one a net alkaline ferruginous pumped mine water, was undertaken to assess the potential of these systems to provide habitats for faunal communities. Both wetlands were found to be impoverished in comparison to natural wetlands but did sustain a macroinvertebrate community that could support higher organisms. Wetland size and water quality in terms of pH, conductivity and metal concentrations were found to be important factors in determining the quality of the populations supported. Direct toxicity to organisms was unlikely to be the main cause of lower diversity, but the smothering of organisms via the precipitation of iron hydroxides particularly in the early parts of the treatment systems affected macroinvertebrate communities. The presence of areas of open water within the planted systems was found to be important for providing habitats for macroinvertebrates and this should be both a future design and maintenance consideration for environmental managers. - Mine-water treatment wetlands can be engineered to provide habitats for ecological communities

  13. Influence of riparian canopy on macroinvertebrate composition and food habits of juvenile salmonids in several Oregon streams.

    Science.gov (United States)

    William R. Meehan

    1996-01-01

    The community composition of macroinvertebrates and the feeding habits of juvenile salmonids were studied in eight Oregon streams. Benthic, drift, sticky trap, and water trap samples were taken over a 3-year period, along with stomach samples of the fish. Samples were taken in stream reaches with and without riparian canopy. Both main effects—fish diet versus...

  14. Differences found in the macroinvertebrate community composition in the presence or absence of the invasive alien crayfish, Orconectes hylas

    Science.gov (United States)

    Freeland-Riggert, Brandye T.; Cairns, Stefan H.; Poulton, Barry C.; Riggert, Chris M.

    2016-01-01

    Introductions of alien species into aquatic ecosystems have been well documented, including invasions of crayfish species; however, little is known about the effects of these introductions on macroinvertebrate communities. The woodland crayfish (Orconectes hylas (Faxon)) has been introduced into the St. Francis River watershed in southeast Missouri and has displaced populations of native crayfish. The effects of O. hylas on macroinvertebrate community composition were investigated in a fourth-order Ozark stream at two locations, one with the presence of O. hylas and one without. Significant differences between sites and across four sampling periods and two habitats were found in five categories of benthic macroinvertebrate metrics: species richness, percent/composition, dominance/diversity, functional feeding groups, and biotic indices. In most seasons and habitat combinations, the invaded site had significantly higher relative abundance of riffle beetles (Coleoptera: Elmidae), and significantly lower Missouri biotic index values, total taxa richness, and both richness and relative abundance of midges (Diptera: Chironomidae). Overall study results indicate that some macroinvertebrate community differences due to the O. hylas invasion were not consistent between seasons and habitats, suggesting that further research on spatial and temporal habitat use and feeding ecology of Ozark crayfish species is needed to improve our understanding of the effects of these invasions on aquatic communities.

  15. Macroinvertebrates in North American tallgrass prairie soils: effects of fire, mowing, and fertilization on density and biomass

    Science.gov (United States)

    M.A. Callaham; J.M. Blair; T.C. Todd; D.J. Kitchen; M.R. Whiles

    2003-01-01

    The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups. and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station. we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term...

  16. Sources of beta diversity in estuarine benthic macro-invertebrate communities in the Baltic Sea - North Sea transition

    DEFF Research Database (Denmark)

    Josefson, Alf B.; Göke, Cordula

    Identification of sources of beta diversity, the change of diversity, is important to understand regulation of overall diversity. Additive partitioning of diversity (species richness and expH) compared to random, was performed on a quantitative benthic macro-invertebrate collection of > 400 speci...

  17. Scale-dependence of the correlation between human population and the species richness of stream macro-invertebrates

    DEFF Research Database (Denmark)

    Pecher, C.; Fritz, Susanne; Marini, L.

    2010-01-01

    . This is surprising as EPT are bio-indicators of stream pollution and most local studies report higher species richness of these macro-invertebrates where human influences on water quality are lower. Using a newly collated taxonomic dataset, we studied whether the species richness of EPT is related to human...

  18. Macroinvertebrate communities associated with littoral zone habitats and the influence of environmental factors in Malilangwe Reservoir, Zimbabwe

    Directory of Open Access Journals (Sweden)

    Dalu T.

    2012-10-01

    Full Text Available The aim of our study was to investigate macroinvertebrate communities so as to understand factors and processes structuring macroinvertebrate communities in a small reservoir, Malilangwe reservoir over seven months (April to October. Sampling was performed by active sweep netting and searching soil sediments. Water temperature, conductivity, dissolved oxygen, pH, ammonia, nitrogen, phosphorus, chemical oxygen demand and macrophyte cover were determined. In total, forty-two macroinvertebrate families belonging to 10 orders were identified amongst 13 macrophyte species and sediments. Thiaridae and Physidae (Mollusca were the dominant and most abundant taxa (57.71% and there were followed by the Hemiptera (27.31%. High indices for sites 1 to 3 for the Simpsons index, the Shannon-Weaver index and evenness were recorded, while low indices were observed for sites 4 to 5, with significant differences being observed among the study site using the Kruskal-Wallis ANOVA test (p < 0.05. Redundancy Analysis revealed that among environmental factors, hydrologically linked parameters such as conductivity, water level and macrophyte cover had the strongest influence on macroinvertebrate distribution.

  19. Hearing diversity in moths confronting a neotropical bat assemblage.

    Science.gov (United States)

    Cobo-Cuan, Ariadna; Kössl, Manfred; Mora, Emanuel C

    2017-09-01

    The tympanal ear is an evolutionary acquisition which helps moths survive predation from bats. The greater diversity of bats and echolocation strategies in the Neotropics compared with temperate zones would be expected to impose different sensory requirements on the neotropical moths. However, even given some variability among moth assemblages, the frequencies of best hearing of moths from different climate zones studied to date have been roughly the same: between 20 and 60 kHz. We have analyzed the auditory characteristics of tympanate moths from Cuba, a neotropical island with high levels of bat diversity and a high incidence of echolocation frequencies above those commonly at the upper limit of moths' hearing sensitivity. Moths of the superfamilies Noctuoidea, Geometroidea and Pyraloidea were examined. Audiograms were determined by non-invasively measuring distortion-product otoacoustic emissions. We also quantified the frequency spectrum of the echolocation sounds to which this moth community is exposed. The hearing ranges of moths in our study showed best frequencies between 36 and 94 kHz. High sensitivity to frequencies above 50 kHz suggests that the auditory sensitivity of moths is suited to the sounds used by sympatric echolocating bat fauna. Biodiversity characterizes predators and prey in the Neotropics, but the bat-moth acoustic interaction keeps spectrally matched.

  20. Ecological response of a multi-purpose river development project using macro-invertebrates richness and fish habitat value

    International Nuclear Information System (INIS)

    Pellaud, M.

    2007-05-01

    SYNERGIE project optimizer taking into account all the project poles. The system of interest is composed of a buffering reservoir of ca. 1 km 2 , a run-off-the- river dam, a hydro power-plant, and an artificial river ensuring longitudinal continuum. The primary part of the work consisted in an extensive literature review on system understanding, anthropic alterations and quality assessment / prediction tool available. The approach consisted of two levels (1) the general ecological considerations to be followed at the project reservoir scale and (2) the measure of the downstream ecological response through modeling. General ecological considerations at the reservoir scale were the implementation of an artificial river ensuring longitudinal connectivity, implementation of artificial ecotonal boosters and the allocation of a sanctuary zone with limited public access. The downstream measure of ecological integrity was based on the choice of three taxonomic groups of macroinvertebrates and four ecological guilds (groups) of fish. Mayflies (Ephemeroptera), stoneflies (Plecoptera) and caddisflies (Trichoptera) richness were predicted using simple hydrological and morphological covariates (i.e. substrate, current speed,...) coupled to system specific faunistic surveys. Bank, riffle, pool and midstream fish guilds habitat values were determined using existing methods. By using the simulation results of river development project scenarios as inputs, the ecological response (i.e. the measure of ecological integrity) was computed following the assumptions that high predicted macro-invertebrate richness and high guilds habitat values were linked to a high ecological integrity. An emphasis on the hydro peaking effect in relation with river morphology was performed on macroinvertebrates. They were found to respond well to hydrological and morphological changes induced by river development projects while the approach by fish habitat value encountered limitations in its applicability. Four

  1. Estimation of the Potential Detection of Diatom Assemblages Based on Ocean Color Radiance Anomalies in the North Sea

    Directory of Open Access Journals (Sweden)

    Anne-Hélène Rêve-Lamarche

    2017-12-01

    Full Text Available Over the past years, a large number of new approaches in the domain of ocean-color have been developed, leading to a variety of innovative descriptors for phytoplankton communities. One of these methods, named PHYSAT, currently allows for the qualitative detection of five main phytoplankton groups from ocean-color measurements. Even though PHYSAT products are widely used in various applications and projects, the approach is limited by the fact it identifies only dominant phytoplankton groups. This current limitation is due to the use of biomarker pigment ratios for establishing empirical relationships between in-situ information and specific ocean-color radiance anomalies in open ocean waters. However, theoretical explanations of PHYSAT suggests that it could be possible to detect more than dominance cases but move more toward phytoplanktonic assemblage detection. Thus, to evaluate the potential of PHYSAT for the detection of phytoplankton assemblages, we took advantage of the Continuous Plankton Recorder (CPR survey, collected in both the English Channel and the North Sea. The available CPR dataset contains information on diatom abundance in two large areas of the North Sea for the period 1998-2010. Using this unique dataset, recurrent diatom assemblages were retrieved based on classification of CPR samples. Six diatom assemblages were identified in-situ, each having indicators taxa or species. Once this first step was completed, the in-situ analysis was used to empirically associate the diatom assemblages with specific PHYSAT spectral anomalies. This step was facilitated by the use of previous classifications of regional radiance anomalies in terms of shape and amplitude, coupled with phenological tools. Through a matchup exercise, three CPR assemblages were associated with specific radiance anomalies. The maps of detection of these specific radiances anomalies are in close agreement with current in-situ ecological knowledge.

  2. Application of Water Quality and Ecology Indices of Benthic Macroinvertebrate to Evaluate Water Quality of Tertiary Irrigation in Malang District

    Directory of Open Access Journals (Sweden)

    Desi Kartikasari

    2013-12-01

    Full Text Available This research aims to determine the water quality of tertiary irrigation in several subdistricts in Malang, namely Kepanjen, Karangploso, and Tumpang. The water quality depends on the water quality indices (National Sanitation Foundation’s-NSF Indices and O’Connor’s Indices based on variables TSS, TDS, pH, DO, and Nitrate concentrate and ecological indices of benthic macroinvertebrate (Diversity Indices Shannon-Wiener, Hilsenhof Biotic Indices-HBI, Average Score per Taxon-ASPT which is calculated by Biological Monitoring Working Party-BMWP, Ephemeroptera Indices, Plecoptera, Trichoptera-EPT. Observation of the physico-chemical water quality and benthic macroinvertebrate on May 2012 to April 2013. The sampling in each subdistrict was done at two selected stations in tertiary irrigation channel with three plot at each station. The data of physico-chemical quality of water were used to calculate the water quality indices, while the benthic macroinvertebrate data were used to calculate the ecological indices. The research findings showed that 27 taxa of benthic macroinvertebrates belong 10 classes were found in the three subdistrict. The pH, DO, Nitrate, TSS and TDS in six tertiary irrigation channels in Malang still met the water quality standards based on Government Regulation No. 82 of 2001 on Management of Water Quality and Water Pollution Control Class III. Based on NSF-WQI indices and O'Connor's Indices, water qualities in these irrigation channels were categorized into medium or moderate (yellow to good (green category. However, based on benthic macroinvertebrate communities which was used to determine the HBI, the water quality in the irrigation channels were categorized into the fair category (fairly significant organic pollution to fairly poor (significant organic pollution, while based on the value of ASPT, the water were categorized into probable moderate pollution to probable severe pollution. The irrigation water which was

  3. Analysis of benthic macroinvertebrates and biotic indices to evaluate water quality in rivers impacted by mining activities in northern Chile

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    Alvial I.E.

    2013-02-01

    Full Text Available Catchments in the semiarid regions are especially susceptible to environmental perturbation associated with water scarcity, hydrological variations and overuse by anthropogenic activities. Using multivariate analysis to relate environmental and biological data, and diversity and biotic indices (ChBMWP, ChIBF, we analyzed the macroinvertebrate composition of 12 rivers of the semiarid region of northern Chile. A non-metric multidimensional scaling for macroinvertebrate taxa and a principal component analysis for environmental variables strongly separated upstream sites (e.g. Vacas Heladas and Malo Rivers, which presented low pH and high dissolved metal concentrations, from other sites. Effectively, CCA showed that metals and low pH, associated with the altitudinal gradient, determined the distributional patterns of macroinvertebrates in the Elqui catchment. The causes of these particular conditions could be related to geological processes and human impact. The biotic indices applied to the sampling sites corroborated and reflected these characteristics, with La Laguna and Turbio Rivers showing a diverse macroinvertebrate community and moderate to good water quality, and the Claro River showing favorable conditions for the development of aquatic biota, indicating its better quality relative to other stations. To the middle and low part of the basin, a change in the composition of the community was observed, with species that suggest an impact by an increase in organic matter, due to agricultural activities and urban settlements concentrated in this area. Our results suggest that macroinvertebrate taxa in northern Chile may be exceptional species, adapted to unfavorable geochemical conditions, and emphasize the need for protection of the semiarid basins of the region.

  4. Environmental gradients structure gorgonian assemblages on coral reefs in SE Sulawesi, Indonesia

    Science.gov (United States)

    Rowley, Sonia J.

    2018-06-01

    Indonesian coral reefs are the epicenter of marine biodiversity, yet are under rapid anthropogenically induced decline. Therefore, ecological monitoring of high diversity taxa is paramount to facilitate effective management and conservation. This study presents an initial report from a comprehensive survey of shallow-water (0-15 m) gorgonian assemblage composition and structure across sites with varying habitat quality within the Wakatobi Marine National Park (WMNP), SE Sulawesi, Indonesia. Current estimates of over 90 morphospecies from 38 genera and 12 families within the calcaxonian, holaxonian and scleraxonian groups are reported. This extensive survey confirms high local gorgonian abundance, diversity and species richness in the absence of anthropogenic influence and increasing with depth. Notably, morphological variants of the zooxanthellate species Isis hippuris Linnaeus, 1758, and Briareum Blainville, 1830, drive site and habitat assemblage differences across environmental gradients. Azooxanthellate taxa, particularly within the Plexauridae, drive species richness and diversity with depth. Of the 14 predictor variables measured, benthic characteristics, water flow and natural light explained just 30% of gorgonian assemblage structure. Furthermore, zooxanthellate and azooxanthellate taxa partitioned distinct gorgonian communities into two trophic groups—autotrophs and heterotrophs, respectively—with contrasting diversity and abundance patterns within and between study sites. This study strongly supports the WMNP as an area of high regional gorgonian abundance and diversity. Varying ecological patterns across environmental clines can provide the foundation for future research and conservation management strategies in some of the most biodiverse marine ecosystems in the world.

  5. Habitat characteristics and environmental parameters influencing fish assemblages of karstic pools in southern Mexico

    Directory of Open Access Journals (Sweden)

    María Eugenia Vega-Cendejas

    Full Text Available Fish assemblage structure was evaluated and compared among 36 karstic pools located within protected areas of the Calakmul Biosphere Reserve (southern Mexico and unprotected adjacent areas beyond the Reserve. Nonmetric multidimensional scaling (MDS, indicator species analysis (ISA, and canonical correspondence analysis (CCA were used to identify which environmental factors reflected local influences and to evaluate the correlation of these variables with fish assemblages structure. Thirty-one species were encountered in these karstic pools, some for the first time within the Reserve. These aquatic environments were separated into three groups based on physico-chemical characteristics. Although CCA identified significant associations between several fish species (based on their relative abundance and environmental variables (K, NH4, NO3, and conductivity, the most abundant species (Astyanax aeneus, Poecilia mexicana, and Gambusia sexradiata occur in most pools and under several environmental conditions. Baseline data on fish diversity along with a continued monitoring program are essential in order to evaluate the conservation status of fish assemblages and their habitats, as well as to measure the influence of anthropogenic impacts on pristine habitats such as the karstic pools of the Calakmul Biosphere Reserve.

  6. Widespread microplastic ingestion by fish assemblages in tropical estuaries subjected to anthropogenic pressures

    International Nuclear Information System (INIS)

    Vendel, A.L.; Bessa, F.; Alves, V.E.N.; Amorim, A.L.A.; Patrício, J.; Palma, A.R.T.

    2017-01-01

    Our aim was to quantify microplastic ingestion by fish assemblages in two tropical Brazilian estuaries and to evaluate whether biological and ecological factors influence the ingestion of microplastics by fish species. Of 2233 fish from both estuaries (from 69 species) examined in this study, 9% of the individuals (24 species) had microplastics in their gut contents. Microplastic ingestion occurred irrespective of fish size and functional group. The diet of fish species was analyzed based on prey items identified in the fish's full stomach contents and five feeding guilds were defined. Microplastics were common throughout all feeding guilds. Low (average ingestion values 1.06 ± 0.30 items/total fish) but widespread occurrence among estuaries also indicates proliferation of microplastic pollution. Our findings highlight the need to focus on assemblage level studies to understand the real magnitude of the problem and emphasize the urgency of mitigation measures directed at microplastic pollution in estuarine ecosystems. - Highlights: • We analyzed microplastic ingestion in 69 fish species collected along two estuaries. • Microplastic ingestion was widespread in fish assemblages in two tropical estuaries. • Microplastic ingestion was independent of fish size and fish functional groups. • Microplastics were observed in fish from five different feeding guilds. • The level of anthropogenic pressures did not influence microplastic ingestion.

  7. Determinants of Tree Assemblage Composition at the Mesoscale within a Subtropical Eucalypt Forest

    Science.gov (United States)

    Hero, Jean-Marc; Butler, Sarah A.; Lollback, Gregory W.; Castley, James G.

    2014-01-01

    A variety of environmental processes, including topography, edaphic and disturbance factors can influence vegetation composition. The relative influence of these patterns has been known to vary with scale, however, few studies have focused on environmental drivers of composition at the mesoscale. This study examined the relative importance of topography, catchment flow and soil in influencing tree assemblages in Karawatha Forest Park; a South-East Queensland subtropical eucalypt forest embedded in an urban matrix that is part of the Terrestrial Ecosystem Research Network South-East Queensland Peri-urban SuperSite. Thirty-three LTER plots were surveyed at the mesoscale (909 ha), where all woody stems ≥1.3 m high rooted within plots were sampled. Vegetation was divided into three cohorts: small (≥1–10 cm DBH), intermediate (≥10–30 cm DBH), and large (≥30 cm DBH). Plot slope, aspect, elevation, catchment area and location and soil chemistry and structure were also measured. Ordinations and smooth surface modelling were used to determine drivers of vegetation assemblage in each cohort. Vegetation composition was highly variable among plots at the mesoscale (plots systematically placed at 500 m intervals). Elevation was strongly related to woody vegetation composition across all cohorts (R2: 0.69–0.75). Other topographic variables that explained a substantial amount of variation in composition were catchment area (R2: 0.43–0.45) and slope (R2: 0.23–0.61). Soil chemistry (R2: 0.09–0.75) was also associated with woody vegetation composition. While species composition differed substantially between cohorts, the environmental variables explaining composition did not. These results demonstrate the overriding importance of elevation and other topographic features in discriminating tree assemblage patterns irrespective of tree size. The importance of soil characteristics to tree assemblages was also influenced by topography, where ridge top sites were

  8. Factors affecting assemblage attributes of freshwater Oligochaeta in Neotropical shallow floodplain lakes

    Directory of Open Access Journals (Sweden)

    Vanessa Ernandes de Amo

    2017-12-01

    Full Text Available Abstract Aim: Identify the effects of sediment composition and water conditions on diversity, richness, evenness, density and composition of freshwater Oligochaeta in shallow floodplain lakes. Methods We sampled 13 shallow floodplain lakes quarterly during the year 2010 in the Upper Paraná River floodplain. In each lake, four sediment samples were taken from the shore and central regions, three of them were used for biological analysis, and one for granulometric analysis. Concomitantly, temperature, dissolved oxygen, pH, conductivity, alkalinity, turbidity and chlorophyll-a were also measured. Initially, the biological samples were analyzed by a stereoscopic microscope. Oligochaeta individuals were identified under optical microscope at the lowest possible taxonomic level. For data analysis, we quantified density, richness, evenness and diversity index of freshwater Oligochaeta. In order to show differences between the months and the analyzed lakes, in relation to the percentages of coarse and fine organic material, the nonparametric Kruskal Wallis test was used. We also calculated the sediment granulometric diversity using the Shannon-Wienner index, using a simple regression analysis. We correlated assemblage attributes of Oligochaeta with sediment diversity and the assemblage species with the limnological variables using the Spearman correlation. Results A total of 2,090 individuals were found distributed among 27 species. From the total individuals number, 57% were Pristina americana, followed by Dero (Dero righii with 13%. Assemblage attributes were not significantly correlated with sediment diversity, and 7 of the 27 species recorded showed significant correlations with at least some of the abiotic variables. Conclusions We verified that the abiotic variables of the water present greater influence on the attributes of the assemblage of freshwater Oligochaeta, when compared with sediment influences. Although we found low local diversity of

  9. Human impacts on functional and taxonomic homogenization of plateau fish assemblages in Yunnan, China

    Directory of Open Access Journals (Sweden)

    Guohuan Su

    2015-07-01

    Full Text Available Human activities and the consequent extinctions of native species and invasions of non-native species have been changing the composition of species assemblages worldwide. These anthropogenic impacts alter not only the richness of assemblages but also the biological dissimilarity among them. However, much of the research effort to date has focused on changes in taxonomic dissimilarity (i.e. accounting for species composition whether assessments of functional dissimilarity (i.e. accounting for the diversity of biological traits are much more scarce, despite revealing important complimentary information by accounting for changes in the diversity of biological traits. Here, we assess the temporal (1950s against 2000s changes in both taxonomic and functional dissimilarities of freshwater fish assemblages across lakes from the Yunnan Plateau in China. The Jaccard index to quantify the changes in both taxonomic and functional dissimilarity. We then partitioned dissimilarity to extract its turnover component and measured the changes in the contribution of turnover to dissimilarity. We found that functional and taxonomic homogenization occurred simultaneously. However, patterns between these two processes differed for some lakes. Taxonomic and functional homogenizations were stronger when the historical level of taxonomic dissimilarity among assemblages was high. The impact of extinctions of native species and invasions of non-native species on homogenization was otherwise complex to disentangle with no significant effect of any of the studied environmental factors. In agreement with other studies, our study proved that change in taxonomic dissimilarity cannot be used to predict changes in functional dissimilarity and, as an indicator of ecosystem functioning, functional dissimilarity should be used together with taxonomic dissimilarity to attain a more holistic understanding of human impacts on natural ecosystems.

  10. Exploring coral microbiome assemblages in the South China Sea.

    Science.gov (United States)

    Cai, Lin; Tian, Ren-Mao; Zhou, Guowei; Tong, Haoya; Wong, Yue Him; Zhang, Weipeng; Chui, Apple Pui Yi; Xie, James Y; Qiu, Jian-Wen; Ang, Put O; Liu, Sheng; Huang, Hui; Qian, Pei-Yuan

    2018-02-05

    Coral reefs are significant ecosystems. The ecological success of coral reefs relies on not only coral-algal symbiosis but also coral-microbial partnership. However, microbiome assemblages in the South China Sea corals remain largely unexplored. Here, we compared the microbiome assemblages of reef-building corals Galaxea (G. fascicularis) and Montipora (M. venosa, M. peltiformis, M. monasteriata) collected from five different locations in the South China Sea using massively-parallel sequencing of 16S rRNA gene and multivariate analysis. The results indicated that microbiome assemblages for each coral species were unique regardless of location and were different from the corresponding seawater. Host type appeared to drive the coral microbiome assemblages rather than location and seawater. Network analysis was employed to explore coral microbiome co-occurrence patterns, which revealed 61 and 80 co-occurring microbial species assembling the Galaxea and Montipora microbiomes, respectively. Most of these co-occurring microbial species were commonly found in corals and were inferred to play potential roles in host nutrient metabolism; carbon, nitrogen, sulfur cycles; host detoxification; and climate change. These findings suggest that the co-occurring microbial species explored might be essential to maintain the critical coral-microbial partnership. The present study provides new insights into coral microbiome assemblages in the South China Sea.

  11. Public sphere as assemblage: the cultural politics of roadside memorialization.

    Science.gov (United States)

    Campbell, Elaine

    2013-09-01

    This paper investigates contemporary academic accounts of the public sphere. In particular, it takes stock of post-Habermasian public sphere scholarship, and acknowledges a lively and variegated debate concerning the multiple ways in which individuals engage in contemporary political affairs. A critical eye is cast over a range of key insights which have come to establish the parameters of what 'counts' as a/the public sphere, who can be involved, and where and how communicative networks are established. This opens up the conceptual space for re-imagining a/the public sphere as an assemblage. Making use of recent developments in Deleuzian-inspired assemblage theory - most especially drawn from DeLanda's (2006) 'new philosophy of society' - the paper sets out an alternative perspective on the notion of the public sphere, and regards it as a space of connectivity brought into being through a contingent and heterogeneous assemblage of discursive, visual and performative practices. This is mapped out with reference to the cultural politics of roadside memorialization. However, a/the public sphere as an assemblage is not simply a 'social construction' brought into being through a logic of connectivity, but is an emergent and ephemeral space which reflexively nurtures and assembles the cultural politics (and political cultures) of which it is an integral part. The discussion concludes, then, with a consideration of the contribution of assemblage theory to public sphere studies. (Also see Campbell 2009a). © London School of Economics and Political Science 2013.

  12. Multilevel Hierarchical Modeling of Benthic Macroinvertebrate Responses to Urbanization in Nine Metropolitan Regions across the Conterminous United States

    Science.gov (United States)

    Kashuba, Roxolana; Cha, YoonKyung; Alameddine, Ibrahim; Lee, Boknam; Cuffney, Thomas F.

    2010-01-01

    Multilevel hierarchical modeling methodology has been developed for use in ecological data analysis. The effect of urbanization on stream macroinvertebrate communities was measured across a gradient of basins in each of nine metropolitan regions across the conterminous United States. The hierarchical nature of this dataset was harnessed in a multi-tiered model structure, predicting both invertebrate response at the basin scale and differences in invertebrate response at the region scale. Ordination site scores, total taxa richness, Ephemeroptera, Plecoptera, Trichoptera (EPT) taxa richness, and richness-weighted mean tolerance of organisms at a site were used to describe invertebrate responses. Percentage of urban land cover was used as a basin-level predictor variable. Regional mean precipitation, air temperature, and antecedent agriculture were used as region-level predictor variables. Multilevel hierarchical models were fit to both levels of data simultaneously, borrowing statistical strength from the complete dataset to reduce uncertainty in regional coefficient estimates. Additionally, whereas non-hierarchical regressions were only able to show differing relations between invertebrate responses and urban intensity separately for each region, the multilevel hierarchical regressions were able to explain and quantify those differences within a single model. In this way, this modeling approach directly establishes the importance of antecedent agricultural conditions in masking the response of invertebrates to urbanization in metropolitan regions such as Milwaukee-Green Bay, Wisconsin; Denver, Colorado; and Dallas-Fort Worth, Texas. Also, these models show that regions with high precipitation, such as Atlanta, Georgia; Birmingham, Alabama; and Portland, Oregon, start out with better regional background conditions of invertebrates prior to urbanization but experience faster negative rates of change with urbanization. Ultimately, this urbanization

  13. Sediment and carbon deposition vary among vegetation assemblages in a coastal salt marsh

    Directory of Open Access Journals (Sweden)

    J. J. Kelleway

    2017-08-01

    Sporobolus assemblages, compared to high retention and preservation of organic inputs in the Juncus assemblage. By combining medium-term accretion quantification with short-term deposition measurements and chemical analyses, we have gained novel insights into above-ground biophysical processes that may explain previously observed regional differences in surface dynamics among key salt marsh vegetation assemblages. Our results suggest that Sarcocornia and Sporobolus assemblages may be particularly susceptible to changes in sea level, though quantification of below-ground processes (e.g. root production, compaction is needed to confirm this.

  14. Community-level response of fishes and aquatic macroinvertebrates to stream restoration in a third-order tributary of the Potomac River, USA

    Science.gov (United States)

    Selego, Stephen M.; Rose, Charnee L.; Merovich, George T.; Welsh, Stuart A.; Anderson, James T.

    2012-01-01

    Natural stream channel design principles and riparian restoration practices were applied during spring 2010 to an agriculturally impaired reach of the Cacapon River, a tributary of the Potomac River which flows into the Chesapeake Bay. Aquatic macroinvertebrates and fishes were sampled from the restoration reach, two degraded control, and two natural reference reaches prior to, concurrently with, and following restoration (2009 through 2010). Collector filterers and scrapers replaced collector gatherers as the dominant macroinvertebrate functional feeding groups in the restoration reach. Before restoration, based on indices of biotic integrity (IBI), the restoration reach fish and macroinvertebrate communities closely resembled those sampled from the control reaches, and after restoration more closely resembled those from the reference reaches. Although the macroinvertebrate community responded more favorably than the fish community, both communities recovered quickly from the temporary impairment caused by the disturbance of restoration procedures and suggest rapid improvement in local ecological conditions.

  15. Community-Level Response of Fishes and Aquatic Macroinvertebrates to Stream Restoration in a Third-Order Tributary of the Potomac River, USA

    Directory of Open Access Journals (Sweden)

    Stephen M. Selego

    2012-01-01

    Full Text Available Natural stream channel design principles and riparian restoration practices were applied during spring 2010 to an agriculturally impaired reach of the Cacapon River, a tributary of the Potomac River which flows into the Chesapeake Bay. Aquatic macroinvertebrates and fishes were sampled from the restoration reach, two degraded control, and two natural reference reaches prior to, concurrently with, and following restoration (2009 through 2010. Collector filterers and scrapers replaced collector gatherers as the dominant macroinvertebrate functional feeding groups in the restoration reach. Before restoration, based on indices of biotic integrity (IBI, the restoration reach fish and macroinvertebrate communities closely resembled those sampled from the control reaches, and after restoration more closely resembled those from the reference reaches. Although the macroinvertebrate community responded more favorably than the fish community, both communities recovered quickly from the temporary impairment caused by the disturbance of restoration procedures and suggest rapid improvement in local ecological conditions.

  16. Soil nematode assemblages as bioindicators of radiation impact in the Chernobyl Exclusion Zone

    International Nuclear Information System (INIS)

    Lecomte-Pradines, C.; Bonzom, J.-M.; Della-Vedova, C.; Beaugelin-Seiller, K.; Villenave, C.; Gaschak, S.; Coppin, F.; Dubourg, N.; Maksimenko, A.; Adam-Guillermin, C.; Garnier-Laplace, J.

    2014-01-01

    In radioecology, the need to understand the long-term ecological effects of radioactive contamination has been emphasised. This requires that the health of field populations is evaluated and linked to an accurate estimate of received radiological dose. The aim of the present study was to assess the effects of current radioactive contamination on nematode assemblages at sites affected by the fallout from the Chernobyl accident. First, we estimated the total dose rates (TDRs) absorbed by nematodes, from measured current soil activity concentrations, Dose Conversion Coefficients (DCCs, calculated using EDEN software) and soil-to-biota concentration ratios (from the ERICA tool database). The impact of current TDRs on nematode assemblages was then evaluated. Nematodes were collected in spring 2011 from 18 forest sites in the Chernobyl Exclusion Zone (CEZ) with external gamma dose rates, measured using radiophotoluminescent dosimeters, varying from 0.2 to 22 μGy h −1 . These values were one order of magnitude below the TDRs. A majority of bacterial-, plant-, and fungal-feeding nematodes and very few of the disturbance sensitive families were identified. No statistically significant association was observed between TDR values and nematode total abundance or the Shannon diversity index (H′). The Nematode Channel Ratio (which defines the relative abundance of bacterial- versus fungal-feeding nematodes) decreased significantly with increasing TDR, suggesting that radioactive contamination may influence nematode assemblages either directly or indirectly by modifying their food resources. A greater Maturity Index (MI), usually characterising better soil quality, was associated with higher pH and TDR values. These results suggest that in the CEZ, nematode assemblages from the forest sites were slightly impacted by chronic exposure at a predicted TDR of 200 μGy h −1 . This may be imputable to a dominant proportion of pollutant resistant nematodes in all sites. This might

  17. Soil nematode assemblages as bioindicators of radiation impact in the Chernobyl Exclusion Zone

    Energy Technology Data Exchange (ETDEWEB)

    Lecomte-Pradines, C., E-mail: catherine.lecomte-pradines@irsn.fr [Institute for Radioprotection and Nuclear Safety, IRSN/PRP-ENV/SERIS, LECO, Building 186, Cadarache 13115 Saint Paul lez Durance cedex (France); Bonzom, J.-M. [Institute for Radioprotection and Nuclear Safety, IRSN/PRP-ENV/SERIS, LECO, Building 186, Cadarache 13115 Saint Paul lez Durance cedex (France); Della-Vedova, C. [Magelis, 6, rue Frederic Mistral, 84160 Cadenet (France); Beaugelin-Seiller, K. [Institute for Radioprotection and Nuclear Safety, IRSN/PRP-ENV/SERIS, LM2E, Building 159, Cadarache 13115 Saint Paul lez Durance cedex (France); Villenave, C. [ELISOL Environment, Building 12, Campus de la Gaillarde, 2 place Viala, 34060 Montpellier cedex 2 (France); Gaschak, S. [Chernobyl Center for Nuclear Safety, Radioactive Waste and Radioecology, International Radioecology Laboratory, 07100 Slavutych (Ukraine); Coppin, F. [Institute for Radioprotection and Nuclear Safety, IRSN/PRP-ENV/SERIS, L2BT, Building 186, Cadarache 13115 Saint Paul lez Durance cedex (France); Dubourg, N. [Institute for Radioprotection and Nuclear Safety, IRSN/PRP-ENV/SERIS, GARM Building 186, Cadarache 13115 Saint Paul lez Durance cedex (France); Maksimenko, A. [Chernobyl Center for Nuclear Safety, Radioactive Waste and Radioecology, International Radioecology Laboratory, 07100 Slavutych (Ukraine); Adam-Guillermin, C. [Institute for Radioprotection and Nuclear Safety, IRSN/PRP-ENV/SERIS, LECO, Building 186, Cadarache 13115 Saint Paul lez Durance cedex (France); Garnier-Laplace, J. [Institute for Radioprotection and Nuclear Safety, IRSN/PRP-ENV/SERIS, Building 159, Cadarache 13115 Saint Paul lez Durance cedex (France)

    2014-08-15

    In radioecology, the need to understand the long-term ecological effects of radioactive contamination has been emphasised. This requires that the health of field populations is evaluated and linked to an accurate estimate of received radiological dose. The aim of the present study was to assess the effects of current radioactive contamination on nematode assemblages at sites affected by the fallout from the Chernobyl accident. First, we estimated the total dose rates (TDRs) absorbed by nematodes, from measured current soil activity concentrations, Dose Conversion Coefficients (DCCs, calculated using EDEN software) and soil-to-biota concentration ratios (from the ERICA tool database). The impact of current TDRs on nematode assemblages was then evaluated. Nematodes were collected in spring 2011 from 18 forest sites in the Chernobyl Exclusion Zone (CEZ) with external gamma dose rates, measured using radiophotoluminescent dosimeters, varying from 0.2 to 22 μGy h{sup −1}. These values were one order of magnitude below the TDRs. A majority of bacterial-, plant-, and fungal-feeding nematodes and very few of the disturbance sensitive families were identified. No statistically significant association was observed between TDR values and nematode total abundance or the Shannon diversity index (H′). The Nematode Channel Ratio (which defines the relative abundance of bacterial- versus fungal-feeding nematodes) decreased significantly with increasing TDR, suggesting that radioactive contamination may influence nematode assemblages either directly or indirectly by modifying their food resources. A greater Maturity Index (MI), usually characterising better soil quality, was associated with higher pH and TDR values. These results suggest that in the CEZ, nematode assemblages from the forest sites were slightly impacted by chronic exposure at a predicted TDR of 200 μGy h{sup −1}. This may be imputable to a dominant proportion of pollutant resistant nematodes in all sites

  18. Shaping up: a geometric morphometric approach to assemblage ecomorphology.

    Science.gov (United States)

    Bower, L M; Piller, K R

    2015-09-01

    This study adopts an ecomorphological approach to test the utility of body shape as a predictor of niche relationships among a stream fish assemblage of the Tickfaw River (Lake Pontchartrain Basin) in southeastern Louisiana, U.S.A. To examine the potential influence of evolutionary constraints, analyses were performed with and without the influence of phylogeny. Fish assemblages were sampled throughout the year, and ecological data (habitat and tropic guild) and body shape (geometric morphometric) data were collected for each fish specimen. Multivariate analyses were performed to examine relationships and differences between body shape and ecological data. Results indicate that a relationship exists between body shape and trophic guild as well as flow regime, but no significant correlation between body shape and substratum was found. Body shape was a reliable indicator of position within assemblage niche space. © 2015 The Fisheries Society of the British Isles.

  19. Surface-water hydrology and quality, and macroinvertebrate and smallmouth bass populations in four stream basins in southwestern Wisconsin, 1987-90

    Science.gov (United States)

    Graczyk, David J.; Lillie, Richard A.; Schlesser, Roger A.; Mason, John W.; Lyons, John D.; Kerr, Roger A.; Graczyk, David J.

    1993-01-01

    Data on streamflow, water quality, and macroinvertebrate and smallmouth bass (microptercus dolomieni) populations were collected from July 1987 through September 1990, in four streams in southwestern Wisconsin to determine the effect of surface-water hydrology and quality on populations of macroinvertebrates and smallmouth bass. The study was a joint project of the U.S. Geological Survey and the Wisconsin Department of Natural Resources.

  20. Habitat specialization in tropical continental shelf demersal fish assemblages.

    Directory of Open Access Journals (Sweden)

    Ben M Fitzpatrick

    Full Text Available The implications of shallow water impacts such as fishing and climate change on fish assemblages are generally considered in isolation from the distribution and abundance of these fish assemblages in adjacent deeper waters. We investigate the abundance and length of demersal fish assemblages across a section of tropical continental shelf at Ningaloo Reef, Western Australia, to identify fish and fish habitat relationships across steep gradients in depth and in different benthic habitat types. The assemblage composition of demersal fish were assessed from baited remote underwater stereo-video samples (n = 304 collected from 16 depth and habitat combinations. Samples were collected across a depth range poorly represented in the literature from the fringing reef lagoon (1-10 m depth, down the fore reef slope to the reef base (10-30 m depth then across the adjacent continental shelf (30-110 m depth. Multivariate analyses showed that there were distinctive fish assemblages and different sized fish were associated with each habitat/depth category. Species richness, MaxN and diversity declined with depth, while average length and trophic level increased. The assemblage structure, diversity, size and trophic structure of demersal fishes changes from shallow inshore habitats to deeper water habitats. More habitat specialists (unique species per habitat/depth category were associated with the reef slope and reef base than other habitats, but offshore sponge-dominated habitats and inshore coral-dominated reef also supported unique species. This suggests that marine protected areas in shallow coral-dominated reef habitats may not adequately protect those species whose depth distribution extends beyond shallow habitats, or other significant elements of demersal fish biodiversity. The ontogenetic habitat partitioning which is characteristic of many species, suggests that to maintain entire species life histories it is necessary to protect corridors of

  1. Downstream impacts of dams: shifts in benthic invertivorous fish assemblages

    Science.gov (United States)

    Granzotti, Rafaela Vendrametto; Miranda, Leandro E.; Agostinho, Angelo A.; Gomes, Luiz Carlos

    2018-01-01

    Impoundments alter connectivity, sediment transport and water discharge in rivers and floodplains, affecting recruitment, habitat and resource availability for fish including benthic invertivorous fish, which represent an important link between primary producers and higher trophic levels in tropical aquatic ecosystems. We investigated long-term changes to water regime, water quality, and invertivorous fish assemblages pre and post impoundment in three rivers downstream of Porto Primavera Reservoir in south Brazil: Paraná, Baía and Ivinhema rivers. Impacts were distinct in the Paraná River, which is fully obstructed by the dam, less evident in the Baía River which is partially obstructed by the dam, but absent in the unimpounded Ivinhema River. Changes in water regime were reflected mainly as changes in water-level fluctuation with little effect on timing. Water transparency increased in the Paraná River post impoundment but did not change in the Baía and Ivinhema rivers. Changes in fish assemblages included a decrease in benthic invertivorous fish in the Paraná River and a shift in invertivorous fish assemblage structure in the Baía and Paraná rivers but not in the unimpounded Ivinhema River. Changes in water regime and water transparency, caused by impoundment, directly or indirectly impacted invertivorous fish assemblages. Alterations of fish assemblages following environmental changes have consequences over the entire ecosystem, including a potential decrease in the diversity of mechanisms for energy flow. We suggest that keeping existing unimpounded tributaries free of dams, engineering artificial floods, and intensive management of fish habitat within the floodplain may preserve native fish assemblages and help maintain functionality and ecosystem services in highly impounded rivers.

  2. Patterns in reef fish assemblages: Insights from the Chagos Archipelago.

    Science.gov (United States)

    Samoilys, Melita; Roche, Ronan; Koldewey, Heather; Turner, John

    2018-01-01

    Understanding the drivers of variability in the composition of fish assemblages across the Indo-Pacific region is crucial to support coral reef ecosystem resilience. Whilst numerous relationships and feedback mechanisms between the functional roles of coral reef fishes and reef benthic composition have been investigated, certain key groups, such as the herbivores, are widely suggested to maintain reefs in a coral-dominated state. Examining links between fishes and reef benthos is complicated by the interactions between natural processes, disturbance events and anthropogenic impacts, particularly fishing pressure. This study examined fish assemblages and associated benthic variables across five atolls within the Chagos Archipelago, where fishing pressure is largely absent, to better understand these relationships. We found high variability in fish assemblages among atolls and sites across the archipelago, especially for key groups such as a suite of grazer-detritivore surgeonfish, and the parrotfishes which varied in density over 40-fold between sites. Differences in fish assemblages were significantly associated with variable levels of both live and recently dead coral cover and rugosity. We suggest these results reflect differing coral recovery trajectories following coral bleaching events and a strong influence of 'bottom-up' control mechanisms on fish assemblages. Species level analyses revealed that Scarus niger, Acanthurus nigrofuscus and Chlorurus strongylocephalos were key species driving differences in fish assemblage structure. Clarifying the trophic roles of herbivorous and detritivorous reef fishes will require species-level studies, which also examine feeding behaviour, to fully understand their contribution in maintaining reef resilience to climate change and fishing impacts.

  3. Phytoplankton Assemblage Patterns in the Southern Mid-Atlantic Bight

    Science.gov (United States)

    Makinen, Carla; Moisan, Tiffany A. (Editor)

    2012-01-01

    As part of the Wallops Coastal Oceans Observing Laboratory (Wa-COOL) Project, we sampled a time-series transect in the southern Mid-Atlantic Bight (MAB) biweekly. Our 2-year time-series data included physical parameters, nutrient concentrations, and chlorophyll a concentrations. A detailed phytoplankton assemblage structure was examined in the second year. During the 2-year study, chlorophyll a concentration (and ocean color satellite imagery) indicated that phytoplankton blooms occurred in January/February during mixing conditions and in early autumn under stratified conditions. The chlorophyll a concentrations ranged from 0.25 microgram 1(exp -1) to 15.49 microgram 1(exp -1) during the 2-year period. We were able to discriminate approximately 116 different species under phase contrast microscopy. Dominant phytoplankton included Skeletonema costatum, Rhizosolenia spp., and Pseudo-nitzschia pungens. In an attempt to determine phytoplankton species competition/succession within the assemblage, we calculated a Shannon Weaver diversity index for our diatom microscopy data. Diatom diversity was greatest during the winter and minimal during the spring. Diatom diversity was also greater at nearshore stations than at offshore stations. Individual genera appeared patchy, with surface and subsurface patches appearing abruptly and persisting for only 1-2 months at a time. The distribution of individual species differed significantly from bulk variables of the assemblage (chlorophyll a ) and total phytoplankton assemblage (cells), which indicates that phytoplankton species may be limited in growth in ways that differ from those of the total assemblage. Our study demonstrated a highly diverse phytoplankton assemblage throughout the year, with opportunistic species dominating during spring and fall in response to seasonal changes in temperature and nutrients in the southern MAB.

  4. Patterns in reef fish assemblages: Insights from the Chagos Archipelago

    Science.gov (United States)

    Roche, Ronan; Koldewey, Heather; Turner, John

    2018-01-01

    Understanding the drivers of variability in the composition of fish assemblages across the Indo-Pacific region is crucial to support coral reef ecosystem resilience. Whilst numerous relationships and feedback mechanisms between the functional roles of coral reef fishes and reef benthic composition have been investigated, certain key groups, such as the herbivores, are widely suggested to maintain reefs in a coral-dominated state. Examining links between fishes and reef benthos is complicated by the interactions between natural processes, disturbance events and anthropogenic impacts, particularly fishing pressure. This study examined fish assemblages and associated benthic variables across five atolls within the Chagos Archipelago, where fishing pressure is largely absent, to better understand these relationships. We found high variability in fish assemblages among atolls and sites across the archipelago, especially for key groups such as a suite of grazer-detritivore surgeonfish, and the parrotfishes which varied in density over 40-fold between sites. Differences in fish assemblages were significantly associated with variable levels of both live and recently dead coral cover and rugosity. We suggest these results reflect differing coral recovery trajectories following coral bleaching events and a strong influence of ‘bottom-up’ control mechanisms on fish assemblages. Species level analyses revealed that Scarus niger, Acanthurus nigrofuscus and Chlorurus strongylocephalos were key species driving differences in fish assemblage structure. Clarifying the trophic roles of herbivorous and detritivorous reef fishes will require species-level studies, which also examine feeding behaviour, to fully understand their contribution in maintaining reef resilience to climate change and fishing impacts. PMID:29351566

  5. A classic Late Frasnian chondrichthyan assemblage from southern Belgium

    Science.gov (United States)

    Ginter, Michał; Gouwy, Sofie; Goolaerts, Stijn

    2017-09-01

    Samples from the Upper Frasnian (Devonian) of Lompret Quarry and Nismes railway section in Dinant Synclinorium, southern Belgium, yielded several chondrichthyan teeth and scales. The teeth belong to three genera: Phoebodus, Cladodoides and Protacrodus. The comparison with selected Late Frasnian chondrichthyan assemblages from the seas between Laurussia and Gondwana revealed substantial local differences of taxonomic composition due to palaeoenvironmental conditions, such as depth, distance to submarine platforms, oxygenation of water, and possibly also temperature. The assemblage from Belgium, with its high frequency of phoebodonts, is the most similar to that from the Ryauzyak section, South Urals, Russia, and the Horse Spring section, Canning Basin, Australia.

  6. Modelling of acid-base titration curves of mineral assemblages

    Directory of Open Access Journals (Sweden)

    Stamberg Karel

    2016-01-01

    Full Text Available The modelling of acid-base titration curves of mineral assemblages was studied with respect to basic parameters of their surface sites to be obtained. The known modelling approaches, component additivity (CA and generalized composite (GC, and three types of different assemblages (fucoidic sandstones, sedimentary rock-clay and bentonite-magnetite samples were used. In contrary to GC-approach, application of which was without difficulties, the problem of CA-one consisted in the credibility and accessibility of the parameters characterizing the individual mineralogical components.

  7. Rapid Bioassessment Methods for Assessing Stream Macroinvertebrate Community on the Savannah River Site

    Energy Technology Data Exchange (ETDEWEB)

    Specht, W.L.

    1999-11-22

    Macroinvertebrate sampling was performed at 16 locations in the Savannah River Site (SRS) streams using Hester-Dendy multiplate samplers and EPA Rapid Bioassessment Protocols (RBP). Some of the sampling locations were unimpacted, while other locations had been subject to various forms of perturbation by SRS activities. In general, the data from the Hester-Dendy multiplate samplers were more sensitive at detecting impacts than were the RBP data. We developed a Biotic Index for the Hester-Dendy data which incorporated eight community structure, function, and balance parameters. when tested using a data set that was unrelated to the data set that was used in developing the Biotic Index, the index was very successful at detecting impact.

  8. Water Quality Assessment Using Benthic Macroinvertebrates in Saigon River and Its Tributaries, Vietnam

    Directory of Open Access Journals (Sweden)

    Duc Pham Anh

    2016-06-01

    Full Text Available This study to enhance the discussion about the usefulness of benthic macroinvertebrates for water quality assessment in Saigon River and its tributaries. Data from 16 sites were used as a representative example for Saigon River and its tributaries in the area of basin over 4,500 km2, the length through provinces of Tay Ninh, Binh Phuoc, Binh Duong, and Ho Chi Minh City of about 280 km. The data covered the period of dry and rainy seasons in 2015, the survey sampled 16 sites (32 events of the Saigon River and its tributaries selected. To implement this evaluation, the analyses were based on MRC methods and classifications these improved by the scientific group.

  9. River Discharge and Local Scale Habitat Influence LIFE Score Macroinvertebrate LIFE Scores

    DEFF Research Database (Denmark)

    Dunbar, Michael J.; Pedersen, Morten Lauge; Cadman, Dan

    2010-01-01

    Midlands of the U.K., we describe how local-scale habitat features (indexed through River Habitat Survey or Danish Habitat Quality Survey) and changing river flow (discharge) influence the response of a macroinvertebrate community index. The approach has broad applicability in developing regional flow...... Invertebrate index for Flow Evaluation (LIFE), an average of abundance-weighted flow groups which indicate the microhabitat preferences of each taxon for higher velocities and clean gravel/cobble substrata or slow/still velocities and finer substrata. 3. For the Danish fauna, the LIFE score responded to three...... of the channel (negative). In both cases, LIFE responded negatively to features associated with historical channel modification. We suggest that there are several mechanisms for these relationships, including the narrower tolerances of taxa preferring high velocity habitat; these taxa are also continually...

  10. Rapid Bioassessment Methods for Assessing Stream Macroinvertebrate Community on the Savannah River Site

    International Nuclear Information System (INIS)

    Specht, W.L.

    1999-01-01

    Macroinvertebrate sampling was performed at 16 locations in the Savannah River Site (SRS) streams using Hester-Dendy multiplate samplers and EPA Rapid Bioassessment Protocols (RBP). Some of the sampling locations were unimpacted, while other locations had been subject to various forms of perturbation by SRS activities. In general, the data from the Hester-Dendy multiplate samplers were more sensitive at detecting impacts than were the RBP data. We developed a Biotic Index for the Hester-Dendy data which incorporated eight community structure, function, and balance parameters. when tested using a data set that was unrelated to the data set that was used in developing the Biotic Index, the index was very successful at detecting impact

  11. Macroinvertebrate Community Response to the Elimination of Concentrated Feedlot Runoff to a Headwater Stream

    Science.gov (United States)

    Snitgen, J. L.; Moren, M. M.

    2005-05-01

    During rainfall and snow melt events, a first order, cold-water stream was receiving varying amounts of liquefied manure from a concentrated feed lot. Stream restoration efforts included the implementation of best management practices to prevent further discharge of the water/manure mixture to the stream. Physical, chemical and biological data were collected pre-construction and two years post-construction of the containment system at a fixed location downstream of the feedlot. Hilsenhoff Biotic Index scores improved significantly, from 6.79 or "Fairly Poor" before the installation of the manure containment system, to 5.28 or "Good" after the installation of the manure containment system. Taxa richness improved from 25 to 34 and the EPT score improved from 0 to 4. Key words: macroinvertebrate, community response, manure, feedlot runoff, stream restoration

  12. The isolation and characterization of actinobacteria from dominant benthic macroinvertebrates endemic to Lake Baikal.

    Science.gov (United States)

    Axenov-Gribanov, Denis; Rebets, Yuriy; Tokovenko, Bogdan; Voytsekhovskaya, Irina; Timofeyev, Maxim; Luzhetskyy, Andriy

    2016-03-01

    The high demand for new antibacterials fosters the isolation of new biologically active compounds producing actinobacteria. Here, we report the isolation and initial characterization of cultured actinobacteria from dominant benthic organisms' communities of Lake Baikal. Twenty-five distinct strains were obtained from 5 species of Baikal endemic macroinvertebrates of amphipods, freshwater sponges, turbellaria worms, and insects (caddisfly larvae). The 16S ribosomal RNA (rRNA)-based phylogenic analysis of obtained strains showed their affiliation to Streptomyces, Nocardia, Pseudonocardia, Micromonospora, Aeromicrobium, and Agromyces genera, revealing the diversity of actinobacteria associated with the benthic organisms of Lake Baikal. The biological activity assays showed that 24 out of 25 strains are producing compounds active against at least one of the test cultures used, including Gram-negative bacteria and Candida albicans. Complete dereplication of secondary metabolite profiles of two isolated strains led to identification of only few known compounds, while the majority of detected metabolites are not listed in existing antibiotic databases.

  13. The Value of the Freshwater Snail Dip Scoop Sampling Method in Macroinvertebrates Bioassessment of Sugar Mill Wastewater Pollution in Mbandjock, Cameroon

    Directory of Open Access Journals (Sweden)

    Emmanuel Noumi

    2008-03-01

    Full Text Available Macroinvertebrates identification and enumeration may be used as a simple and affordable alternative to chemical analysis in water pollution monitoring. However, the ecological responses of various taxa to pollution are poorly known in resources-limited tropical countries. While freshwater macroinvertebrates have been used in the assessment of water quality in Europe and the Americas, investigations in Africa have mainly focused on snail hosts of human parasites. There is a need for sampling methods that can be used to assess both snails and other macroinvertebrates. The present study was designed to evaluate the usefulness of the freshwater snail dip scoop method in the study of macroinvertebrates for the assessment of the SOSUCAM sugar mill effluents pollution. Standard snail dip scoop samples were collected upstream and downstream of the factory effluent inputs, on the Mokona and Mengoala rivers. The analysis of the macroinvertebrate communities revealed the absence of Ephemeroptera and Trichoptera, and the thriving of Syrphidae in the sections of the rivers under high effluent load. The Shannon and Weaver diversity index was lower in these areas. The dip scoop sampling protocol was found to be a useful method for macroinvertebrates collection. Hence, this method is recommended as a simple, cost-effective and efficient tool for the bio-assessment of freshwater pollution in developing countries with limited research resources.

  14. Aquatic macroinvertebrates associated with Eichhornia azurea (Swartz Kunth and relationships with abiotic factors in marginal lentic ecosystems (São Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    CV. Silva

    Full Text Available Marginal lakes are characterised by their having high biological diversity due to the presence of aquatic macrophytes in their coastal zones, providing habitats for refuge and food for animal community members. Among the fauna components associated with macrophytes, aquatic macroinvertebrates are important because they are an energy source for predators and fish. In six lakes and two different seasons (March and August 2009, the ecological attributes of aquatic macroinvertebrate community associated with Eichhornia azurea were compared and the controlling environmental factors were identified. Since the attributes of macroinvertebrate community are strictly associated with abiotic variables of each distinct habitat, our hypothesis was that each site associated with the same floating aquatic macrophyte (E. azurea should have a typical composition and density of organisms. We identified 50 taxa of macroinvertebrates, with greater taxa richness for aquatic insects (37 taxa divided into eight orders; the order Diptera being the most abundant in the two study periods. On the other hand, higher values of total taxa richness were recorded in August. Dissolved oxygen and pH presented the greatest number of significant positive correlations with the different taxa. The animals most frequently collected in the six lakes in March and August 2009 were Hirudinea, Oligochaeta, Hydrachnidae, Conchostraca, Ostracoda, Noteridae, Ceratopogonidae, Chironomidae, Culicidae, Caenidae, Pleidae, Aeshnidae, Libellulidae, Coenagrionidae and Nematoda. Only densities of Trichoptera, Ostracoda and Conchostraca presented the highest significant differences between lakes in both study periods and considering the composition of macroinvertebrates no significant differences were registered for macroinvertebrate composition.

  15. Colonization of leaf litter of two aquatic macrophytes, Mayaca fluviatilis Aublet and Salvinia auriculata Aublet by aquatic macroinvertebrates in a tropical reservoir

    Directory of Open Access Journals (Sweden)

    Marcia Cristina de Paula

    2011-04-01

    Full Text Available Decomposition and colonization of S. auriculata and M. fluviatilis by macroinvertebrates were analyzed during 40 days to determine whether differences existed on colonization by aquatic macroinvertebrates of two macrophytes with distinct habits (submerged versus fluctuant. Leaf litter of S. auriculata and M. fluviatilis were incubated in 24 litter bags (12 of each species, in a small reservoir surrounded by a cerrado fragment with low level of anthropic impact. After 10, 20, 30 and 40 days, the litter bags were removed and aquatic macroinvertebrates community was analyzed. Two hundred twenty macroinvertebrates were associated with S. auriculata and 261 were associated with M. fluviatilis, identified in 24 taxa. Both macrophyte species were colonized mainly by macroinvertebrate predators. Ablabesmyia with predator and collector food mechanisms was present in all sampling. The data showed an expressive increase of abundance during the process of decomposition and a decrease at the end of the experiment, in both macrophytes. Cluster analysis permitted inference that the colonization of the leaf liter by macroinvertebrates was determinated by incubation time of leaf litter not by the habit of macrophytes (submerged or fluctuant.

  16. Spatial and temporal heterogeneity in a subtropical reservoir and their effects over the benthic macroinvertebrate community

    Directory of Open Access Journals (Sweden)

    Frederico Guilherme de Souza Beghelli

    2014-09-01

    Full Text Available AIM: The objective of the present study was to demonstrate the influences of the environment spatial heterogeneity on benthic macroinvertebrates considering transverse and longitudinal gradients as also seasonality. METHODS: Four samplings were performed: two in the wet and two in the dry season in the riverine, transitional and lacustrine zones in the littoral and profundal regions of Itupararanga reservoir, SP, Brazil. Abiotic characterization of the water and of the sediment was performed. The biotic characterization was based on richness, dominance, diversity, and density of organisms, as well as on the relative abundance of predominant taxa. Two-way ANOSIM analyses were performed for both biotic and abiotic components, in order to test the significance of the differences in the longitudinal and transverse directions as well as of the differences between seasons. RESULTS: Compartmentalization was present in both directions, longitudinal and transverse. In a general way, the littoral region presented higher diversity values when compared with the profundal region, and the riverine zone presented high densities and high percentage of taxons, which usually indicate organic pollution. The differentiation between the transitional and lacustrine zones was determined mainly by taxonomic composition. Seasonality was also observed and the transportation of small particles, the entrance of nutrients, and the presence of macrophytes were considered as determinants for differentiation. CONCLUSIONS: Together, these results demonstrate the responses of benthic macroinvertebrate communities considering distinct sources of variation: longitudinal heterogeneity, determined by the increasing distance from the forming rivers that leads to a gradient of physical and chemical conditions; transverse heterogeneity, determined by the proximity with the land environment and depth differences. Seasonal heterogeneity was recorded during the period of this research and

  17. Benthic macroinvertebrates as bioindicators of water quality in an Atlantic forest fragment

    Directory of Open Access Journals (Sweden)

    Augusto Oliveira

    2010-12-01

    Full Text Available The objective of this study was to evaluate benthic macroinvertebrate communities as bioindicators of water quality in five streams located in the "Reserva Particular do Patrimônio Natural" (RPPN Mata Samuel de Paula and its surroundings, in the municipality of Nova Lima near the city of Belo Horizonte, Minas Gerais State, southeastern Brazil. This region has been strongly modified by human activities including mining and urbanization. Samples were collected in the field every three months between August 2004 and November 2005, totaling six samplings in the rainy and dry seasons. This assessment identified one area ecologically altered while the other sampling sites were found to be minimally disturbed systems, with well-preserved ecological conditions. However, according to the Biological Monitoring Work Party (BMWP and the Average Score Per Taxon (ASPT indices, all sampling sites had excellent water quality. A total of 14,952 organisms was collected, belonging to 155 taxa (148 Insecta, two Annelida, one Bivalvia, one Decapoda, one Planariidae, one Hydracarina, and one Entognatha. The most abundant benthic groups were Chironomidae (47.9%, Simuliidae (12.3%, Bivalvia (7.5%, Decapoda (6.1%, Oligochaeta (5.2%, Polycentropodidae (3.7%, Hydropsychidae (2.5%, Calamoceratidae (1.8%, Ceratopogonidae (1.7%, and Libellulidae (1.2%. The assessment of the benthic functional feeding groups showed that 34% of the macroinvertebrates were collector-gatherers, 29% predators, 24% collector-filterers, 8% shredders, and 5% scrapers. The RPPN Mata Samuel de Paula comprises diversified freshwater habitats that are of great importance for the conservation of many benthic taxa that are intolerant to organic pollution.

  18. Biomonitoring with macroinvertebrate communities in Italy: What happened to our past and what is the future?

    Directory of Open Access Journals (Sweden)

    Tiziano Bo

    2016-10-01

    Full Text Available This paper reviews the history and development of biological water quality assessment using macroinvertebrates in Italy. Italy was one of the first European countries to officially adopt a biomonitoring system based on benthic invertebrates, the Indice Biotico Esteso (IBE. After the European Water Framework Directive (WFD 2000/60/EC, this method was replaced by the “Standardisation of River Classifications_Intercalibration Common Metrics” (STAR_ICM index, which met the new requirements. As this method has been employed for some years, it could be useful to take a provisional stock and to provide some suggestions to ameliorate the current biomonitoring approach, also trying to minimize the break with past practices and better harmonize the history of biomonitoring in Italy. One of the most evident difference between past and current approach is related to the amount of time and effort required in the application of the two methods. STAR_ICMi is a scientifically rigorous and modern method, but much more time-consuming and challenging in both field and laboratory efforts. This fact has various disturbing practical repercussions, i.e., the environmental agencies have generally reduced the number of sampling stations routinely monitored during the year. The aim of our work is to propose some operational changes that would help to simplify and expedite the monitoring process. In particular, regarding fieldwork, we focus on the time and effort required for macroinvertebrate collection, while for laboratory activity we suggest a reshaping of the requested taxonomic detail. Moreover, in this way the data provided by the new approach could be compared with the long time series available from the previous application of IBE.

  19. The influence of urbanisation on macroinvertebrate biodiversity in constructed stormwater wetlands.

    Science.gov (United States)

    Mackintosh, Teresa J; Davis, Jenny A; Thompson, Ross M

    2015-12-01

    The construction of wetlands in urban environments is primarily carried out to assist in the removal of contaminants from wastewaters; however, these wetlands have the added benefit of providing habitat for aquatic invertebrates, fish and waterbirds. Stormwater quantity and quality is directly related to impervious area (roads, sealed areas, roofs) in the catchment. As a consequence, it would be expected that impervious area would be related to contaminant load and biodiversity in receiving waters such as urban wetlands. This study aimed to establish whether the degree of urbanisation and its associated changes to stormwater runoff affected macroinvertebrate richness and abundance within constructed wetlands. Urban wetlands in Melbourne's west and south east were sampled along a gradient of urbanisation. There was a significant negative relationship between total imperviousness (TI) and the abundance of aquatic invertebrates detected for sites in the west, but not in the south east. However macroinvertebrate communities were relatively homogenous both within and between all study wetlands. Chironomidae (non-biting midges) was the most abundant family recorded at the majority of sites. Chironomids are able to tolerate a wide array of environmental conditions, including eutrophic and anoxic conditions. Their prevalence suggests that water quality is impaired in these systems, regardless of degree of urbanisation, although the causal mechanism is unclear. These results show some dependency between receiving wetland condition and the degree of urbanisation of the catchment, but suggest that other factors may be as important in determining the value of urban wetlands as habitat for wildlife. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Model-Based Analysis of the Potential of Macroinvertebrates as Indicators for Microbial Pathogens in Rivers

    Directory of Open Access Journals (Sweden)

    Rubén Jerves-Cobo

    2018-03-01

    Full Text Available The quality of water prior to its use for drinking, farming or recreational purposes must comply with several physicochemical and microbiological standards to safeguard society and the environment. In order to satisfy these standards, expensive analyses and highly trained personnel in laboratories are required. Whereas macroinvertebrates have been used as ecological indicators to review the health of aquatic ecosystems. In this research, the relationship between microbial pathogens and macrobenthic invertebrate taxa was examined in the Machangara River located in the southern Andes of Ecuador, in which 33 sites, according to their land use, were chosen to collect physicochemical, microbiological and biological parameters. Decision tree models (DTMs were used to generate rules that link the presence and abundance of some benthic families to microbial pathogen standards. The aforementioned DTMs provide an indirect, approximate, and quick way of checking the fulfillment of Ecuadorian regulations for water use related to microbial pathogens. The models built and optimized with the WEKA package, were evaluated based on both statistical and ecological criteria to make them as clear and simple as possible. As a result, two different and reliable models were obtained, which could be used as proxy indicators in a preliminary assessment of pollution of microbial pathogens in rivers. The DTMs can be easily applied by staff with minimal training in the identification of the sensitive taxa selected by the models. The presence of selected macroinvertebrate taxa in conjunction with the decision trees can be used as a screening tool to evaluate sites that require additional follow up analyses to confirm whether microbial water quality standards are met.

  1. Effects of an oil spill on leafpack-inhabiting macroinvertebrates in the Chariton river, Missouri

    Science.gov (United States)

    Poulton, B.C.; Callahan, E.V.; Hurtubise, R.D.; Mueller, B.G.

    1998-01-01

    Artificial leaf packs were used to determine the effects of an oil spill on stream macroinvertebrate communities in the Chariton River, Missouri. Plastic mesh leaf retainers with approximately 10 g of leaves from five tree species were deployed at five sites (two upstream of the spill and three downstream) immediately after the spill and one year later. Four macroinvertebrate species dominating the community at upstream sites were virtually eliminated below the spill, including the stonefly Isoperla bilineata, the caddisfly Potamyia flava, the midge Thienemanniella xena, and blackfly larvae (Simulium sp.). Density of collector and shredder functional groups, and number of shredder taxa differed between upstream sites and the two furthest downstream sites during the 1990 sample period (Kruskal-Wallis w/Bonferroni paired comparisons, experiment wise error rate = 0.05). With one exception, no differences between sites were detected in the 1991-1992 sample period, indicating that the benthic community had at least partially recovered from the oil spill after one year. The odds of obtaining a sample with a small abundance of shredders (abundance < median) in 1990 was significantly greater downstream of the spill than upstream, and the odds of obtaining a sample with a small abundance of shredders at downstream sites was greater in 1990 than in 1991-1992. A similar pattern was observed in abundance and taxa richness of the collector functional group. No significant differences between the two sampling periods were detected at upstream sites. Observed effects appeared to be associated with oil sorption and substrate coating, creating conditions unsuitable for successful colonization.

  2. POPs data for salmonids and macroinvertebrates from Glacier Bay, Alaska - Measuring persistent organic pollutants in resident salmonids and benthic macroinvertebrates in streams near Glacier National Park, Alaska

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A 2007 pilot study was initiated by the University of Alaska Southeast in which baseline levels of contaminants, including persistent organic pollutants (POPs) and...

  3. Effects of phylogeny, leaf traits, and the altitudinal distribution of host plants on herbivore assemblages on congeneric Acer species.

    Science.gov (United States)

    Nakadai, Ryosuke; Murakami, Masashi; Hirao, Toshihide

    2014-08-01

    Historical, niche-based, and stochastic processes have been proposed as the mechanisms that drive community assembly. In plant-herbivore systems, these processes can correspond to phylogeny, leaf traits, and the distribution of host plants, respectively. Although patterns of herbivore assemblages among plant species have been repeatedly examined, the effects of these factors among co-occurring congeneric host plant species have rarely been studied. Our aim was to reveal the process of community assembly for herbivores by investigating the effects of phylogeny, leaf traits, and the altitudinal distribution of closely related host plants of the genus Acer. We sampled leaf functional traits for 30 Acer species in Japan. Using a newly constructed phylogeny, we determined that three of the six measured leaf traits (leaf thickness, C/N ratio, and condensed tannin content) showed a phylogenetic signal. In a field study, we sampled herbivore communities on 14 Acer species within an elevation gradient and examined relationships between herbivore assemblages and host plants. We found that herbivore assemblages were significantly correlated with phylogeny, leaf traits, phylogenetic signals, and the altitudinal distribution of host plants. Our results indicate that the interaction between historical and current ecological processes shapes herbivore community assemblages.

  4. The ichthyoplankton assemblage and the environmental variables off the NW and N Iberian Peninsula coasts, in early spring

    Science.gov (United States)

    Rodriguez, J. M.; Gonzalez-Nuevo, G.; Gonzalez-Pola, C.; Cabal, J.

    2009-05-01

    Ichthyoplankton and mesozooplankton were sampled and fluorescence and physical environmental variables were measured off the NW and N Iberian Peninsula coasts, during April 2005. A total of 51 species of fish larvae, belonging to 26 families, were recorded. Sardina pilchardus, with 43.8% and 58.7% of the total fish egg and larval catches, respectively, dominated the ichthyoplankton assemblage. The study area was divided by a cross-shelf frontal structure into two hydrographic regions that coincided with the Atlantic and Cantabrian geographic regions. Ichthyoplankton abundance was higher in the Cantabrian region while larval diversity was higher in the Atlantic region. This was the main alongshore variability in the structure of the larval fish assemblage. Nevertheless, the stronger variability, related with the presence of a shelf-slope front, was found in the central-eastern Cantabrian region where two major larval fish assemblages, an "outer" and a "coastal", were distinguished. The Atlantic region, where the shelf-slope front was not found, was inhabited by a single larval fish assemblage. Canonical correspondence analysis revealed that, off the NW and N Iberian Peninsula coasts, the horizontal distribution of larval fish species in early spring may be explained by a limited number of environmental variables. Of these, the most important were the physical variables depth and sea surface temperature.

  5. Epilithic algal assemblages in the Forsmark Biotest basin

    Energy Technology Data Exchange (ETDEWEB)

    Snoeijs, P.

    1987-04-01

    The Forsmark Biotest Basin is an artificial offshore brackish lake, through which the cooling water is led from the Forsmark Nuclear Power Station on the Swedish east coast. The Biotest Basin differs from the Bothnian Sea surrounding it by a temperature elevation of up to 10 degrees C, no ice cover in winter, and an artificial, fast current. At 11 sites in- and outside the basin, benthic algal assemblages on stones in the hydrolittoral belt were sampled every third week during one year. Cover abundances were estimated for all algae occurring on the stones, but for diatoms only when they formed blooms. The results of the vegetation analyses are given. Diversity indices and dominance-diversity curves were computed for each site on the basis of pooled data for the cold season and for the rest of the year. The algae included both unicellular and multicellular forms. In total 88 taxa were distinguished in the species lists: 29 Cyanophyta, 7 Rhodophyta, 1 Chrysophyceae, 9 Fucophyceae, 17 Diatomophyceae and 25 Chlorophyta. In terms of percentage cover-abundance, blue-green and green algae increased with temperature, while red and brown algae and diatoms decreased with temperature in the interval between the minimum (0 degrees C) and the maximum (25.7 degrees C) water temperatures that were measured during the investigation period. Melosira spp. and Nitzschia filiformis proved to be the diatoms most favoured by the cooling water discharge. Lower diversity and greater dominance of one or a few species over the other was caused by thermal discharge at sites with fast-flowing water, but the opposite occurred at sites with quiescent water, mainly due to a greater number and higher abundances of blue-green algal species and thread-like green algae at the latter sites. This report also gives some notes on taxonomy of the encountered species.

  6. Demersal Assemblages on the Soft Bottoms off the Catalan-Levante Coast of the Spanish Mediterranean

    Directory of Open Access Journals (Sweden)

    Mariano García-Rodríguez

    2011-01-01

    Full Text Available The analysis of 255 bottom trawl samples obtained in annual experimental surveys (2007–2010 along the western Mediterranean shows the existence of five well-defined demersal assemblages that follow a depth distribution: (a upper shelf assemblages, including two assemblages differentiated by the type of substrate (sand-muddy and terrigenous muddy bottoms; (b a middle shelf assemblage; (c an upper slope assemblage; (d a middle slope assemblage. Faunally, they are dominated by fish (37% of 452 total species, followed by crustaceans (22%, molluscs (17%, echinoderms (9%, and other invertebrates (15%. The assemblages identified showed major alterations on the shelf and shelf edge and less pronounced ones on the upper and middle slope. The average diversity values were more or less high, evidencing the high species richness in the western Mediterranean. The identified assemblages may facilitate future multispecies fisheries management based on an ecosystem approach.

  7. The Liana assemblage of a Congolian rainforest : diversity, structure and dynamics

    NARCIS (Netherlands)

    Ewango Ekokinya, Corneille

    2010-01-01

    Key words: Liana assemblage, species composition, community, dynamics, canopy openness, Manniophyton fulvum, functional traits, population density, pervasive change.

    This study analyzes the diversity, composition, and dynamics of the liana assemblage of the Ituri rain forest in

  8. [Characteristics of ichthyoplankton assemblages in Yangtze Estuary and adjacent waters in spring].

    Science.gov (United States)

    Liu, Shu-De; Xian, Wei-Wei; Liu, Dong

    2008-10-01

    Based on the investigation data of ichthyoplankton assemblages and environmental factors in Yangtze Estuary and adjacent waters in May 1999 and 2001, the characteristics of ichthyoplankton assemblages in these areas in spring were studied by using TWINSPAN (two-way indicator species analysis) and CCA (canonical correspondence analysis). A total of 11 540 ichthyoplankton individuals were taxonomically identified, belonging to 11 orders, 18 families and 32 species, of which, Coilia mystus, Engraulis japonicus, Chaeturichthys hexanema, Allanetta bleekeri, and Trachidermis fasciatus were the dominant species. The ichthyoplankton communities were classified into three assemblages by using TWINSPAN, i.e., estuarine assemblage dominated by C. mystus, coastal assemblage dominated by A. bleekeri and T. fasciatus; and shelf assemblage featured by E. japonicus and C. hexanema. The CCA ordination of the interrelations among the three assemblages and their correlations to the environmental variables revealed that salinity, depth, dissolved oxygen, and total suspended particulate matter were the major factors affecting the ichthyoplankton assemblages in the study areas.

  9. Learning in the "Platform Society": Disassembling an Educational Data Assemblage

    Science.gov (United States)

    Williamson, Ben

    2017-01-01

    Schools are increasingly involved in diverse forms of student data collection. This article provides a sociotechnical survey of a data assemblage used in education. ClassDojo is a commercial platform for tracking students' behaviour data in classrooms and a social media network for connecting teachers, students, and parents. The hybridization of…

  10. The distribution patterns of Red Sea Chaetodontid assemblages

    NARCIS (Netherlands)

    Zekeria, ZA; Afeworki, Y; Videler, JJ; Zekeria, A.

    2005-01-01

    1. The occurrence and abundance of butterflyfishes were investigated in northern, central and southern areas of the Eritrean Red Sea coast. Visual census was used to estimate the presence and abundance of the species along 100-metre long transects. 2. The assemblages of buttertlyfishes from the

  11. Temporal variability in epifaunal assemblages associated with temperate gorgonian gardens

    KAUST Repository

    Dias, I.M.; Curdia, Joao; Cunha, M.R.; Santos, M.N.; Carvalho, Susana

    2015-01-01

    The present study is one of the few that investigate the temporal variability of epifaunal assemblages associated with coral species, particularly the octocorals Eunicella gazella and Leptogorgia lusitanica in south Portugal. The results suggest time rather than colony size as a primary driver of the ecological patterns of these assemblages, which were dominated by amphipods, molluscs and polychaetes. Temporal variability was linked to changes in environmental parameters, namely temperature, chlorophyll a and particulate organic carbon. Hence, temporal variability must be taken into account for the design of future biodiversity assessment studies, as different patterns may be observed depending on the sampling time. Associated epifaunal assemblages were consistently dominated by resident species (i.e. species present in all sampling periods) and a peak of rare species was observed in the transition from spring to summer following the increase of seawater temperature. Turnover was particularly high in the transition between the spring and summer periods. In both hosts, turnover was higher in the small sized colonies, which generally harboured less diverse and less abundant assemblages which also differed from those inhabiting larger size colonies. The high levels of diversity associated with gorgonian colonies highlights the need for the conservation of this priority habitat.

  12. The ichthyoplankton assemblage of the Algoa Bay nearshore region ...

    African Journals Online (AJOL)

    The ichthyoplankton assemblage of the Algoa Bay nearshore region in relation to coastal zone utilization by juvenile fish. ... The various taxa occurring in the ichthyoplankton are discussed in terms of distribution of adults and juveniles, breeding biology and available information on early life history. The paucity of larvae of ...

  13. Changes in density and composition of algal assemblages in certain ...

    African Journals Online (AJOL)

    The water purification plants at Virginia and Bothaville, South Africa, experience problems with cyanobacteria and other algae. Their algal assemblages were studied during 2010 and 2011 to determine the dominant species that may pose problems in purification. Cyanobacteria, diatoms and green algae were the dominant ...

  14. Shikarpur lithic assemblage: New questions regarding Rohri chert blade production

    Directory of Open Access Journals (Sweden)

    Charusmita Gadekar

    2014-03-01

    Full Text Available Recent excavations at Shikarpur, a fortified Harappan site situated near the Gulf of Kuchchh in Gujarat, Western India, brought to light a large collection of Rohri chert blades.  Chert found in the Rohri hill near Sukkur in Sindh, central Pakistan is distinctive and easily identifiable. The wide distribution of standardized Rohri chert blades is often regarded as a testimony to the Harappan efficiency in long distance trade and craft production.  The possibility of localized production of Rohri chert blades in Gujarat is often negated due to the constraints of raw-material availability.  The absence of Rohri chert working debitage from most of the sites in Gujarat, has lent support to this position. The Shikarpur Rohri blade assemblage however incorporates more than 650 blades, a large fluted blade-core and a few Rohri chert debitage.  These have led the excavators to suggest that some of the blades found at Shikarpur were locally produced from raw materials brought to the site from the Rohri hills.  Typo-technological features of the Rohri chert assemblage from Shikarpur have been analysed in this background. These along with metrical features of the assemblage are compared with Rohri chert assemblages from other major Harappan sites in the region to check the validity of the proposed ‘limited local production’.

  15. Cinema Experiences at School: Assemblages as Encounters with Subjectivities

    Science.gov (United States)

    Infante, Marta

    2018-01-01

    The aim of this article is to analyse how 15 students at a public elementary school detach from immobile representations of identity through aesthetic self-expressive work with cinema. Drawing on Deleuze and Guattari's concept of assemblage, I interrogate students' experiences of discrimination and challenge their processes of developing a short…

  16. THE INFLUENCE OF SUBMERGED MACROPHYTES ON SEDIMENTARY DIATOM ASSEMBLAGES(1).

    Science.gov (United States)

    Vermaire, Jesse C; Prairie, Yves T; Gregory-Eaves, Irene

    2011-12-01

    Submerged macrophytes are a central component of lake ecosystems; however, little is known regarding their long-term response to environmental change. We have examined the potential of diatoms as indicators of past macrophyte biomass. We first sampled periphyton to determine whether habitat was a predictor of diatom assemblage. We then sampled 41 lakes in Quebec, Canada, to evaluate whether whole-lake submerged macrophyte biomass (BiomEpiV) influenced surface sediment diatom assemblages. A multivariate regression tree (MRT) was used to construct a semiquantitative model to reconstruct past macrophyte biomass. We determined that periphytic diatom assemblages on macrophytes were significantly different from those on wood and rocks (ANOSIM R = 0.63, P macrophyte, nutrient-limited lakes (BiomEpiV ≥525 μg · L(-1) ; total phosphorus [TP] macrophyte, nutrient-limited lakes (BiomEpiV macrophytes have a significant influence on diatom community structure and that sedimentary diatom assemblages can be used to infer past macrophyte abundance. © 2011 Phycological Society of America.

  17. UV EXPOSURE OF CORAL ASSEMBLAGES IN THE FLORIDA KEYS

    Science.gov (United States)

    Recent studies have indicated that solar radiation can be a significant stressor of coral assemblages in tropical and subtropical marine environments. Here we review the scientific literature related to the interactions of solar radiation with coral reefs, with emphasis on harm...

  18. Microfloral assemblage, age and paleoenvironment of the Upper ...

    African Journals Online (AJOL)

    Microfloral assemblage, age and paleoenvironment of the Upper Cretaceous Patti Formation, southeastern Bida Basin, Nigeria. OJ Ojo, SO Akande. Abstract. No Abstract. Journal of Mining and Geology Vol. 44 (1) 2008: pp. 71-82. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD ...

  19. Temporal variability in epifaunal assemblages associated with temperate gorgonian gardens

    KAUST Repository

    Dias, I.M.

    2015-10-19

    The present study is one of the few that investigate the temporal variability of epifaunal assemblages associated with coral species, particularly the octocorals Eunicella gazella and Leptogorgia lusitanica in south Portugal. The results suggest time rather than colony size as a primary driver of the ecological patterns of these assemblages, which were dominated by amphipods, molluscs and polychaetes. Temporal variability was linked to changes in environmental parameters, namely temperature, chlorophyll a and particulate organic carbon. Hence, temporal variability must be taken into account for the design of future biodiversity assessment studies, as different patterns may be observed depending on the sampling time. Associated epifaunal assemblages were consistently dominated by resident species (i.e. species present in all sampling periods) and a peak of rare species was observed in the transition from spring to summer following the increase of seawater temperature. Turnover was particularly high in the transition between the spring and summer periods. In both hosts, turnover was higher in the small sized colonies, which generally harboured less diverse and less abundant assemblages which also differed from those inhabiting larger size colonies. The high levels of diversity associated with gorgonian colonies highlights the need for the conservation of this priority habitat.

  20. Insect assemblage and the pollination system in cocoa ecosystems

    African Journals Online (AJOL)

    SARAH

    2013-02-27

    Feb 27, 2013 ... Key words: Cocoa, pollinators, insect assemblage, Forcipomyia spp, pollination system. INTRODUCTION ... that the ecological prediction of plant reproductive successes and ..... non-interaction between some resident insects and the cocoa plant might be as a result of evolution of floral structure of the ...

  1. The health of benthic diatom assemblages in lower stretch

    Indian Academy of Sciences (India)

    This study examines the ecological state of epilithic diatom assemblages along the lower stretch of Mandakini, a glacier-fed Himalayan river. The diatoms were sampled at four stations during winter and summer, only once in each season. Valve counts were obtained from Naphrax mounts prepared from each sample.

  2. Reef fish and coral assemblages at Maptaput, Rayong Province

    Directory of Open Access Journals (Sweden)

    Voravit Cheevaporn

    2007-06-01

    Full Text Available This study describes the structure of coral and fish assemblages of a group of small islands and pinnacles in the vicinity of Maptaput deep sea port, Rayong Province, Thailand during 2002. The coral and fish assemblages at Saket Island and nearby pinnacle, Hin-Yai, which are located less than 1 km from the deep sea port, had changed. Living coral cover in 2002 was 8% at Hin-Yai and 4% at Saket Island which decreased from 33% and 64%, respectively in the previous report in 1992. Numbers of coral species at Saket Island decreased from 41 species to 13 species. Acropora spp. that previously dominated the area had nearly disappeared. For fishes, a total of 40 species were found in 2002 the numbers decreased to only 6 species at Saket Island and 36 species at Hin-Yai. Fishes that dominated the area are small pomacentrids. After 1997, the conditions of coral and fish assemblages at Saket Island and Hin-Yai had markedly changed, whereas, the conditions found in the nearby area are much better. Sediment load from port construction was the primary cause of the degradation. This should indicate the adverse effect of sedimentation on coral and reef fish assemblages at Maptaput. Coral communities developed on rock pinnacles west of Maptaput deep-sea port are reported and described herein for the first time.

  3. Response of phytoplankton assemblages isolated for short periods ...

    African Journals Online (AJOL)

    The response of phytoplankton assemblages isolated in enclosures for short periods of time was examined in hyper-eutrophic Lake Chivero (Harare, Zimbabwe), to determine the factors that influenced the structure of the phytoplankton community, after noticing a marked decline in the dominance of Microcystis aeruginosa ...

  4. Climate mediates the effects of disturbance on ant assemblage structure

    Science.gov (United States)

    Gibb, Heloise; Sanders, Nathan J.; Dunn, Robert R.; Watson, Simon; Photakis, Manoli; Abril, Silvia; Andersen, Alan N.; Angulo, Elena; Armbrecht, Inge; Arnan, Xavier; Baccaro, Fabricio B.; Bishop, Tom R.; Boulay, Raphael; Castracani, Cristina; Del Toro, Israel; Delsinne, Thibaut; Diaz, Mireia; Donoso, David A.; Enríquez, Martha L.; Fayle, Tom M.; Feener, Donald H.; Fitzpatrick, Matthew C.; Gómez, Crisanto; Grasso, Donato A.; Groc, Sarah; Heterick, Brian; Hoffmann, Benjamin D.; Lach, Lori; Lattke, John; Leponce, Maurice; Lessard, Jean-Philippe; Longino, John; Lucky, Andrea; Majer, Jonathan; Menke, Sean B.; Mezger, Dirk; Mori, Alessandra; Munyai, Thinandavha C.; Paknia, Omid; Pearce-Duvet, Jessica; Pfeiffer, Martin; Philpott, Stacy M.; de Souza, Jorge L. P.; Tista, Melanie; Vasconcelos, Heraldo L.; Vonshak, Merav; Parr, Catherine L.

    2015-01-01

    Many studies have focused on the impacts of climate change on biological assemblages, yet little is known about how climate interacts with other major anthropogenic influences on biodiversity, such as habitat disturbance. Using a unique global database of 1128 local ant assemblages, we examined whether climate mediates the effects of habitat disturbance on assemblage structure at a global scale. Species richness and evenness were associated positively with temperature, and negatively with disturbance. However, the interaction among temperature, precipitation and disturbance shaped species richness and evenness. The effect was manifested through a failure of species richness to increase substantially with temperature in transformed habitats at low precipitation. At low precipitation levels, evenness increased with temperature in undisturbed sites, peaked at medium temperatures in disturbed sites and remained low in transformed sites. In warmer climates with lower rainfall, the effects of increasing disturbance on species richness and evenness were akin to decreases in temperature of up to 9°C. Anthropogenic disturbance and ongoing climate change may interact in complicated ways to shape the structure of assemblages, with hot, arid environments likely to be at greatest risk. PMID:25994675

  5. Relationships between structural complexity, coral traits, and reef fish assemblages

    Science.gov (United States)

    Darling, Emily S.; Graham, Nicholas A. J.; Januchowski-Hartley, Fraser A.; Nash, Kirsty L.; Pratchett, Morgan S.; Wilson, Shaun K.

    2017-06-01

    With the ongoing loss of coral cover and the associated flattening of reef architecture, understanding the links between coral habitat and reef fishes is of critical importance. Here, we investigate whether considering coral traits and functional diversity provides new insights into the relationship between structural complexity and reef fish communities, and whether coral traits and community composition can predict structural complexity. Across 157 sites in Seychelles, Maldives, the Chagos Archipelago, and Australia's Great Barrier Reef, we find that structural complexity and reef zone are the strongest and most consistent predictors of reef fish abundance, biomass, species richness, and trophic structure. However, coral traits, diversity, and life histories provided additional predictive power for models of reef fish assemblages, and were key drivers of structural complexity. Our findings highlight that reef complexity relies on living corals—with different traits and life histories—continuing to build carbonate skeletons, and that these nuanced relationships between coral assemblages and habitat complexity can affect the structure of reef fish assemblages. Seascape-level estimates of structural complexity are rapid and cost effective with important implications for the structure and function of fish assemblages, and should be incorporated into monitoring programs.

  6. Nematode assemblages in the rhizosphere of spring barley (Hordeum vulgare L.) depended on fertilisation and plant growth phase

    DEFF Research Database (Denmark)

    Madsen, Mette Vestergård

    2004-01-01

    rhizosphere; nitrogen and phosphorus fertilisation; nematode assemblages; plant parasites; barley......rhizosphere; nitrogen and phosphorus fertilisation; nematode assemblages; plant parasites; barley...

  7. Improving the energy efficiency of mine fan assemblages

    International Nuclear Information System (INIS)

    De Souza, Euler

    2015-01-01

    Energy associated with ventilating an underground operation comprises a significant portion of a mine operation's base energy demand and is consequently responsible for a large percentage of the total operating costs. Ventilation systems may account from 25 to 40% of the total energy costs and 40–50% of the energy consumption of a mine operation. Fans are the most important mechanical devices used to ventilate underground mines and the total fan power installed in a single mine operation can easily exceed 10,000 kW. Investigations of a number of mine main fan installations have determined their assemblage to be, in general, very energy inefficient. The author has found that 40–80% of the energy consumed by a main fan is used to overcome the resistance of fan assemblage components. This paper presents how engineering design principles can be applied to improve the performance and efficiency of fan installations, resulting in substantial reductions in power consumption, operating cost and greenhouse gas emissions. A detailed case study is presented to demonstrate that, by designing fan assemblages using proper engineering concepts of fluid physics and industrial ventilation design, main fan systems will operate at efficiencies well above 80–90% (compared to common operating efficiencies of between 20 and 65%), resulting in a drastic reduction in a mine's overall costs and base electrical and energy loads. - Highlights: • Increases in fan assemblage efficiencies with minimum capital investment. • Improved designs for substantial fan power and operating cost savings. • General solutions and tactics for improving existing main fan installations. • Case study presented to demonstrate proper design of fan assemblages.

  8. Depth as an organizer of fish assemblages in floodplain lakes

    Science.gov (United States)

    Miranda, L.E.

    2011-01-01

    Depth reduction is a natural process in floodplain lakes, but in many basins has been accelerated by anthropogenic disturbances. A diverse set of 42 floodplain lakes in the Yazoo River Basin (Mississippi, USA) was examined to test the hypothesis of whether depth reduction was a key determinant of water quality and fish assemblage structure. Single and multiple variable analyses were applied to 10 commonly monitored water variables and 54 fish species. Results showed strong associations between depth and water characteristics, and between depth and fish assemblages. Deep lakes provided less variable environments, clearer water, and a wider range of microhabitats than shallow lakes. The greater environmental stability was reflected by the dominant species in the assemblages, which included a broader representation of large-body species, species less tolerant of extreme water quality, and more predators. Stability in deep lakes was further reflected by reduced among-lake variability in taxa representation. Fish assemblages in shallow lakes were more variable than deep lakes, and commonly dominated by opportunistic species that have early maturity, extended breeding seasons, small adult size, and short lifespan. Depth is a causal factor that drives many physical and chemical variables that contribute to organizing fish assemblages in floodplain lakes. Thus, correlations between fish and water transparency, temperature, oxygen, trophic state, habitat structure, and other environmental descriptors may ultimately be totally or partly regulated by depth. In basins undergoing rapid anthropogenic modifications, local changes forced by depth reductions may be expected to eliminate species available from the regional pool and could have considerable ecological implications. ?? 2010 Springer Basel AG (outside the USA).

  9. Are the streams of the Sinos River basin of good water quality? Aquatic macroinvertebrates may answer the question

    Directory of Open Access Journals (Sweden)

    L. Bieger

    Full Text Available Macroinvertebrate communities are one of the most used groups in assessments of water quality, since they respond directly to the level of contamination of aquatic ecosystems. The main objective of this study was the assessment of the water quality of the Sinos River basin (Rio Grande do Sul state, Brazil through biotic indices based on the macroinvertebrate community ("Family Biotic Index - FBI", and "Biological Monitoring Working Party Score System - BMWP". Three lower order streams (2nd order were selected in each one of three main regions of the basin. In each stream, the samplings were performed in three reaches (upper, middle, and lower, totalling 27 reaches. Two samplings were carried in each reach over one year (winter and summer. A total of 6,847 macroinvertebrates distributed among 54 families were sampled. The streams from the upper region were of better water quality than the lower region. The water quality did not change between the upper, middle and lower reaches of the streams. However, the upper reaches of the streams were of better water quality in all the regions of the basin. The water quality of the streams did not vary between the summer and the winter. This result demonstrated that water quality may be analysed in both studied seasons (summer and winter using biotic indices. The analysis of the results allows us to conclude that the biotic indices used reflected the changes related to the water quality along the longitudinal gradient of the basin. Thus, aquatic macroinvertebrates were important bioindicators of the water and environmental quality of the streams of the Sinos River basin.

  10. Agricultural Rivers at Risk: Dredging Results in a Loss of Macroinvertebrates. Preliminary Observations from the Narew Catchment, Poland

    OpenAIRE

    Mateusz Grygoruk; Magdalena Frąk; Aron Chmielewski

    2015-01-01

    Ecosystem deterioration in small lowland agricultural rivers that results from river dredging entails a significant threat to the appropriate ecohydrological conditions of these water bodies, expressed as homogenization of habitats and loss of biodiversity. Our study was aimed at a comparison of abundance and taxonomic structure of bottom-dwelling macroinvertebrates in dredged and non-dredged stretches of small lowland rivers and tributaries of the middle Narew River, namely: Czaplinianka, Tu...

  11. Spatial variation of macroinvertebrate community structure and associated environmental conditions in a subtropical river system of southeastern China

    Directory of Open Access Journals (Sweden)

    Fu L.

    2015-01-01

    Full Text Available Knowledge of macroinvertebrate distributions and associated environmental drivers in subtropical Asian rivers is relatively scarce. To fill this knowledge gap, we examined the spatial variation of macroinvertebrate community structure and associated environmental conditions in a subtropical river system, the Dongjiang River Basin, in southeastern China. A total of 70 families and 9 classes of macroinvertebrates were identified from 74 sites sampled in January 2013. Our study has the following findings: (1 a distinct spatial differentiation of macroinvertebrate communities was present in the Dongjiang River Basin indicated by non-metric multidimensional scaling (NMDS, which corresponded to the northern region (NR, middle region (MR, and southern region (SR gradient; (2 ANOVAs showed that diversity indices (total taxa, Margalef index and the Shannon diversity index, biotic indices (richness of EPT, percentage of EPT, and family biotic index and most of the studied environmental conditions (elevation, slope, steam order, water temperature, electrical conductivity, dissolved oxygen, pH, substrates, ammoniacal nitrogen, total phosphorus, percentage of urban land, percentage of rural land, and percentage of forest land differed significantly among the three regions and a degradation gradient was observed in the NR–MR–SR direction; (3 Canonical correspondence analysis (CCA revealed that NR sites were characterized by steep slope and coarse substrate, MR sites were characterized by high water temperatures and shallow slopes, and SR sites were primarily characterized by high total phosphorus and ammoniacal nitrogen concentrations; and (4 the Indicator Species Analysis, in conjunction with CCA analysis indicated that the most representative indicator taxon is Tipulidae for NR, Semisulcospira sp. for MR, and Branchiura sp. for SR.

  12. Benthic macroinvertebrates and the use of stable isotopes (δ13C and δ15N) in the impact assessment of peatland use on boreal stream ecosystems

    Science.gov (United States)

    Nieminen, Mika L.; Daza Secco, Emmanuela; Nykänen, Hannu; Meissner, Kristian

    2013-04-01

    Stable isotope analysis (SIA) can provide insights into carbon flow dynamics and trophic positions of consumers in food webs. SIA is used in this study, where we assess the possible changes in the basal resources of Finnish boreal stream ecosystems and differences in the impact of two forms of peatland use, forestry and peat mining. About 30% of the total land area of Finland is classified as peatland, of which about 55% has been drained for forestry and about 0.6% is in peat production. Unlike forestry, peat production is regionally less scattered and can thus have measurable local impacts although the total area of peat production is small. Three watersheds were used as study areas. Within each watershed, one stream drains a subcatchment affected only by peat mining, whereas the other stream flows through a subcatchment affected by forestry. The two subcatchment streams merge to form a single stream flowing into a lake. Studied watersheds were subject to no other forms of land use. In addition to the impacted sites, we used two pristine natural mire and two natural forest catchments as controls. We analysed the stable isotopes of carbon (δ13C) and nitrogen (δ15N) from benthic macroinvertebrates, stream bank soil, stream sediment, and dissolved organic carbon (DOC) in stream water. Samples for stable isotope analyses were collected in the summer of 2011 and samples for invertebrate community analyses in the autumn of 2011. Upon sampling we measured several physical parameters at each sampling site. In addition, stream water samples collected in summer and autumn 2012 were analysed for CH4 and CO2 gas concentrations and autumn gas samples also for their δ13C values. Our initial SIA results of invertebrates suggest some degree of discrimination between different sources of OM and possible effects on feeding habits, presumably due to the quality of the basal resources. We will explore this result further by examining not only taxonomical structure, but also the

  13. Pulsed Source Measurements on a Uranium-Water Subcritical Assembly; Mesures Faites sur un Assemblage Sous- Critique Uranium-Eau Ordinaire a l'Aide d'une Source Pulsee; Izmereniya s pomoshch'yu istochnikov impul'snykh nejtronov na urano-vodnoi podkriticheskoi sborke; Mediciones con Fuentes Pulsantes en un Conjunto Subcritico Uranio-Agua

    Energy Technology Data Exchange (ETDEWEB)

    Gibson, I. H.; Walker, J. [Department of Physics, University of Birmingham, Birmingham (United Kingdom)

    1964-02-15

    An unreflected assembly of natural uranium and light water has been used in conjunction with a pulsed source of neutrons for decay-time measurements at different bucklings. Four different lattice pitches over the range 3.94 cm to 5.08 cm were obtained by using different pairs of accurately machined lattice plates and in each case the uranium was in the form of bars 109.8 cm long and 3.0 cm diameter. The fuel- was mounted horizontally and loadings up to approximately 6 t were involved. Spatial harmonics were eliminated or selected by appropriate placing of a small scintillation detector. Experimental results showing the dependence of decay constant on buckling are presented and compared with theoretical values. (author) [French] On a utilise conjointement un assemblage sans reflecteur uranium naturel-eau ordinaire et une source puisee en vue de mesurer le temps de decroissance pour differents laplaciens. - Plusieurs paires de plaques de reseau usinees avec precision ont permis d'adopter quatre differents pas de reseau allant de 3,94cm a 5,08 cm; dans chaque cas, l'uranium etait sous forme de barres de 109,8 cm de long et de 3,0 cm de diametre. Le combustible etait monte horizontalement et le chargement a atteint parfois jusqu'a pres de 6 t. Grace a un petit detecteur a scintillations convenablement place, on a pu eliminer les harmoniques spatiaux ou les selectionner. Les auteurs presentent des resultats d'experiences qui montrent les variations de la constante de desintegration en fonction du laplacien, et les comparent avec les valeurs theoriques. (author) [Spanish] Los autores utilizaron un conjunto de uranio natural y agua ligera, sin reflector, juntamente con una fuente neutronica pulsante, para efectuar determinaciones del tiempo de desintegracion en correspondencia con diferentes valores del laplaciano. En este conjunto se pueden establecer cuatro diferentes espaciamientos del reticulado, desde 3,94 cm hasta 5,08 cm. utilizando diferentes pares de placas de

  14. Changes in habitat complexity negatively affect diverse gastropod assemblages in coralline algal turf.

    Science.gov (United States)

    Kelaher, B P

    2003-05-01

    The physical structure of a habitat generally has a strong influence on the diversity and abundance of associated organisms. I investigated the role of coralline algal turf structure in determining spatial variation of gastropod assemblages at different tidal heights of a rocky shore near Sydney, Australia. The structural characteristics of algal turf tested were frond density (or structural complexity) and frond length (the vertical scale over which structural complexity was measured). This definition of structural complexity assumes that complexity of the habitat increases with increasing frond density. While frond length was unrelated to gastropod community structure, I found significant correlations between density of fronds and multivariate and univariate measures of gastropod assemblages, indicating the importance of structural complexity. In contrast to previous studies, here there were negative relationships between the density of fronds and the richness and abundance of gastropods. Artificial habitat mimics were used to manipulate the density of fronds to test the hypothesis that increasing algal structural complexity decreases the richness and abundance of gastropods. As predicted, there were significantly more species of gastropods in loosely packed than in tightly packed turf at both low- and mid-shore levels. Despite large differences between gastropod assemblages at different tidal heights, the direction and magnitude of these negative effects were similar at low- and mid-shore levels and, therefore, relatively independent of local environmental conditions. These novel results extend our previous understanding of the ecological effects of habitat structure because they demonstrate possible limitations of commonly used definitions of structural complexity, as well as distinct upper thresholds in the relationship between structural complexity and faunal species richness.

  15. Effects of organic pollution and physical stress on benthic macroinvertebrate communities from two intermittently closed and open coastal lagoons (ICOLLs)

    Science.gov (United States)

    Coelho, Susana; Pérez-Ruzafa, Angel; Gamito, Sofia

    2015-12-01

    Benthic macroinvertebrate communities and environmental conditions were studied in two intermittently closed and open coastal lakes and lagoons (ICOLLs), located in southern Algarve (Foz do Almargem e Salgados), with the purpose of evaluating the effects of organic pollution, originated mainly from wastewater discharges, and the physical stress caused by the irregular opening of the lagoons. Most of the year, lagoons were isolated from the sea, receiving the freshwater inputs from small rivers and in Salgados, also from the effluents of a wastewater plant. According to environmental and biotic conditions, Foz do Almargem presented a greater marine influence and a lower trophic state (mesotrophic) than Salgados (hypereutrophic). Benthic macroinvertebrate communities in the lagoons were distinct, just as their relations with environmental parameters. Mollusca were the most abundant macroinvertebrates in Foz do Almargem, while Insecta, Oligochaeta and Crustacea were more relevant in Salgados. Corophium multisetosum occurred exclusively in Salgados stations and, just as Chironomus sp., other Insecta and Oligochaeta, densities were positively related to total phosphorus, clay content and chlorophyll a concentration in the sediment, chlorophyll a concentration in water and with total dissolved inorganic nitrogen. Abra segmentum, Cerastoderma glaucum, Peringia ulvae and Ecrobia ventrosa occurred only in Foz do Almargem, with lower values of the above mentioned parameters. Both lagoons were dominated by deposit feeders and taxa tolerant to environmental stress, although in Salgados there was a greater occurrence of opportunistic taxa associated to pronounced unbalanced situations, due to excess organic matter enrichment.

  16. Disturbance caused by freshwater releases of different magnitude on the aquatic macroinvertebrate communities of two coastal lagoons

    Science.gov (United States)

    Cañedo-Argüelles, Miguel; Rieradevall, Maria

    2010-06-01

    The response of the aquatic macroinvertebrate communities to freshwater releases of different magnitude and persistence was investigated in two Mediterranean coastal lagoons (Ca l'Arana and Ricarda). The study was carried out during 14 months (June 2004-July 2005) in which different environmental variables and the macroinvertebrate communities associated with two different habitats, the Phragmites australis belt and the deep area of the lagoons, were sampled monthly. Additionally, potential colonizing sources were identified through the analysis of Chironomidae pupal exuviae. The initial response of the communities to the freshwater releases was similar, being characterized by a peak of opportunistic taxa (mainly Naididae), but the late response was different for each lagoon. In the Ca l'Arana, the magnitude of the freshwater release was higher (salinity dropped below five, which is the limit commonly established for most freshwater species) and its persistence was also higher, allowing the colonization of the lagoon by new insect taxa, which replaced the brackish water species. In the Ricarda, the salinity never dropped beyond five and pre-disturbance conditions were rapidly re-established. This, together with the acclimatizing mechanisms showed by the species Chironomus riparius and Hediste diversicolor, permitted the recovery of the pre-disturbance macroinvertebrate community.

  17. Tolerance of benthic macroinvertebrates to organic enrichment in highland streams of northeastern Rio Grande do Sul, Brazil

    Directory of Open Access Journals (Sweden)

    Aline Correa Mazzoni

    2014-06-01

    Full Text Available AIM: the aim of this study was to determine the ecological valence of benthic macroinvertebrates at different pollution levels in highland rivers and streams of Rio Grande do Sul; METHODS: the dataset proceeds from samplings performed between 2002-2011 in 35 lotic ecosystems. The Chemical Index was used to determine pollution levels. Indices of richness and Shannon diversity were applied to characterize the structure of benthic communities. The descriptors used to determine taxa's ecological valence were selected according to Coefficient of Variation and regression analyses. Groups of tolerance were identified using Interquartile range and cluster analysis; RESULTS: Conductivity and Chemical Index were the descriptors best related with diversity of benthic macroinvertebrate community. These metrics were used to determine the tolerance range of 38 taxa. Interquartile range and cluster analysis revealed three groups of taxa, according to their occurrence in different levels of pollution: taxa with narrow amplitudes, present at sites with very low or very high load of organic enrichment; taxa with moderate amplitude, found until moderately polluted sites; and taxa with occurrence in widespread environmental conditions. The results, when compared to other studies in Brazil, showed differences in some taxa's tolerance. This observation indicates the need to assess the bioindication potential of these taxa in genus and species level; CONCLUSION: the present study contributes to increase knowledge about the bioindicator potential of benthic macroinvertebrates. Therefore, the study supports an advanced biomonitoring of ecological quality in mountain streams of southern Brazil.

  18. Assessment of macroinvertebrate communities in adjacent urban stream basins, Kansas City, Missouri, metropolitan area, 2007 through 2011

    Science.gov (United States)

    Christensen, Eric D.; Krempa, Heather M.

    2013-01-01

    Macroinvertebrates were collected as part of two separate urban water-quality studies from adjacent basins, the Blue River Basin (Kansas City, Missouri), the Little Blue River and Rock Creek Basins (Independence, Missouri), and their tributaries. Consistent collection and processing procedures between the studies allowed for statistical comparisons. Seven Blue River Basin sites, nine Little Blue River Basin sites, including Rock Creek, and two rural sites representative of Missouri ecological drainage units and the area’s ecoregions were used in the analysis. Different factors or levels of urban intensity may affect the basins and macroinvertebrate community metrics differently, even though both basins are substantially developed above their downstream streamgages (Blue River, 65 percent; Little Blue River, 52 percent). The Blue River has no flood control reservoirs and receives wastewater effluent and stormflow from a combined sewer system. The Little Blue River has flood control reservoirs, receives no wastewater effluent, and has a separate stormwater sewer system. Analysis of macroinvertebrate community structure with pollution-tolerance metrics and water-quality parameters indicated differences between the Blue River Basin and the Little Blue River Basin.

  19. Assessment of river quality in a subtropical Austral river system: a combined approach using benthic diatoms and macroinvertebrates

    Science.gov (United States)

    Nhiwatiwa, Tamuka; Dalu, Tatenda; Sithole, Tatenda

    2017-12-01

    River systems constitute areas of high human population densities owing to their favourable conditions for agriculture, water supply and transportation network. Despite human dependence on river systems, anthropogenic activities severely degrade water quality. The main aim of this study was to assess the river health of Ngamo River using diatom and macroinvertebrate community structure based on multivariate analyses and community metrics. Ammonia, pH, salinity, total phosphorus and temperature were found to be significantly different among the study seasons. The diatom and macroinvertebrate taxa richness increased downstream suggesting an improvement in water as we moved away from the pollution point sources. Canonical correspondence analyses identified nutrients (total nitrogen and reactive phosphorus) as important variables structuring diatom and macroinvertebrate community. The community metrics and diversity indices for both bioindicators highlighted that the water quality of the river system was very poor. These findings indicate that both methods can be used for water quality assessments, e.g. sewage and agricultural pollution, and they show high potential for use during water quality monitoring programmes in other regions.

  20. Richness and density of aquatic benthic macroinvertebrates after exposure to fungicides and insecticides in rice paddy fields

    Directory of Open Access Journals (Sweden)

    ALANA C.D. WANDSCHEER

    Full Text Available ABSTRACT The objective of this study was to verify the richness and density of aquatic benthic macroinvertebrates after exposure to fungicides and insecticides of the rice paddy fields. In the crop seasons of 2012/13 and 2013/14, field experiments were performed, which consisted of single-dose applications of the fungicides trifloxystrobin + tebuconazole and tricyclazole, and the insecticides lambda-cyhalothrin + thiamethoxam and diflubenzuron, in 10 m2 experimental plots, over rice plants in the R3 stage. Control plots with and without rice plants were maintained in order to simulate a natural environment. Soil samples were collected during rice cultivation for assessment of the macroinvertebrate fauna. Chemical-physical parameters assessed in the experiments included temperature, pH and oxygen dissolved in the water and pesticide persistence in the water and in the soil. The application of a single dose of the pesticides and fungicides in the recommended period does not cause significant negative effects over the richness and density of the macroinvertebrates. Tebuconazole, tricyclazole and thiamethoxam showed high persistence in the irrigation water of rice paddy fields. Thus, the doses and number of applications of these products in crops should be carefully handled in order to avoid contamination of the environment.

  1. Richness and density of aquatic benthic macroinvertebrates after exposure to fungicides and insecticides in rice paddy fields.

    Science.gov (United States)

    Wandscheer, Alana C D; Marchesan, Enio; Santos, Sandro; Zanella, Renato; Silva, Marília F; Londero, Guilherme P; Donato, Gabriel

    2017-01-01

    The objective of this study was to verify the richness and density of aquatic benthic macroinvertebrates after exposure to fungicides and insecticides of the rice paddy fields. In the crop seasons of 2012/13 and 2013/14, field experiments were performed, which consisted of single-dose applications of the fungicides trifloxystrobin + tebuconazole and tricyclazole, and the insecticides lambda-cyhalothrin + thiamethoxam and diflubenzuron, in 10 m2 experimental plots, over rice plants in the R3 stage. Control plots with and without rice plants were maintained in order to simulate a natural environment. Soil samples were collected during rice cultivation for assessment of the macroinvertebrate fauna. Chemical-physical parameters assessed in the experiments included temperature, pH and oxygen dissolved in the water and pesticide persistence in the water and in the soil. The application of a single dose of the pesticides and fungicides in the recommended period does not cause significant negative effects over the richness and density of the macroinvertebrates. Tebuconazole, tricyclazole and thiamethoxam showed high persistence in the irrigation water of rice paddy fields. Thus, the doses and number of applications of these products in crops should be carefully handled in order to avoid contamination of the environment.

  2. Assessing condition of macroinvertebrate communities and bed sediment toxicity in the Rochester Embayment Area of Concern, New York, USA

    Science.gov (United States)

    Duffy, Brian; George, Scott D.; Baldigo, Barry P.; Smith, Alexander J.

    2017-01-01

    The United States and Canada agreed to restore the chemical, physical, and biological integrity of the Great Lakes ecosystem under the first Great Lakes Water Quality Agreement in 1972. The lowest reach of the Genesee River and the Rochester Embayment on Lake Ontario between Bogus Point and Nine Mile Point, including Braddock Bay, were designated as an Area of Concern (AOC) due to effects of contaminated sediments and physical disturbance on several beneficial uses. Following sediment remedial efforts and with conditions improving in the AOC, the present study was conducted to reevaluate the status of the benthic macroinvertebrate (benthos) beneficial use impairment (BUI). Benthic macroinvertebrate community assessments and 10-day Chironomus dilutus bioassays were used to test the hypotheses that sediments within the AOC were no more toxic than sediments from surrounding reference areas. The study was separated into three discrete systems (Genesee River, Lake Ontario, and Braddock Bay) and non-parametric analyses determined that a multimetric index of benthic macroinvertebrate community integrity was significantly higher at AOC sites compared to reference sites on the Genesee River and in Braddock Bay while AOC and reference sites on Lake Ontario did not differ significantly. Survival and growth of C. dilutus were also similar between AOC and reference sites for each system with the exception of significantly higher growth at reference sites on Lake Ontario. Results generally indicated that the condition of benthos and toxicity of sediment of the Rochester Embayment AOC are similar to or better than that in the surrounding area.

  3. Seasonal changes of the pelagic fish assemblage in a temperate estuary

    Science.gov (United States)

    Hagan, S. M.; Able, K. W.

    2003-01-01

    The pelagic (i.e. fishes that spend most of their time swimming and feeding in the water column) fish assemblage was examined within a temperate estuary to determine the seasonal patterns of abundance, biomass, richness, and species composition. These measures were related to abiotic measures including temperature, salinity, water transparency, and depth. Pelagic fish (nGasterosteus aculeatus and age 1+ by M. menidia. Spring (April-early June) was overwhelmingly dominated by age 0+ C. harengus. Early summer (late June-early July) was relatively species rich and characterized by age 0+ of Brevoortia tyrannus, Pomatomus saltatrix, Alosa pseudoharengus, and age 1+ of A. mitchilli. Late summer (late July-August) remained relatively species rich and included mostly age 0+ of A. mitchilli, A. hepsetus, and M. menidia. Autumn (September-November) continued to have high catches of age 0+ of M. menidia and A. mitchilli. As expected for temperate estuaries, the best of the measured abiotic predictors of these groupings included temperature, salinity, and degree of change in temperature. However, timing of life history characteristics, such as location, and timing of reproduction and migration also influenced the seasonal occurrence of these pelagic species. The large abundance and biomass of a relatively few species, as observed in this study, are typical of estuaries, although this is one of the few studies that have focused solely on the pelagic component of estuarine fish assemblages.

  4. Protocol for Monitoring Fish Assemblages in Pacific Northwest National Parks

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    Brenkman, Samuel J.; Connolly, Patrick J.

    2008-01-01

    Rivers and streams that drain from Olympic, Mount Rainier, and North Cascades National Parks are among the most protected corridors in the lower 48 States, and represent some of the largest tracts of contiguous, undisturbed habitat throughout the range of several key fish species of the Pacific Northwest. These watersheds are of high regional importance as freshwater habitat sanctuaries for native fish, where habitat conditions are characterized as having little to no disturbance from development, channelization, impervious surfaces, roads, diversions, or hydroelectric projects. Fishery resources are of high ecological and cultural importance in Pacific Northwest National Parks, and significantly contribute to economically important recreational, commercial, and tribal fisheries. This protocol describes procedures to monitor trends in fish assemblages, fish abundance, and water temperature in eight rivers and five wadeable streams in Olympic National Park during summer months, and is based on 4 years of field testing. Fish assemblages link freshwater, marine, and terrestrial ecosystems. They also serve as focal resources of national parks and are excellent indicators of ecological conditions of rivers and streams. Despite the vital importance of native anadromous and resident fish populations, there is no existing monitoring program for fish assemblages in the North Coast and Cascades Network. Specific monitoring objectives of this protocol are to determine seasonal and annual trends in: (1) fish species composition, (2) timing of migration of adult fish, (3) relative abundance, (4) age and size structure, (5) extent of non-native and hatchery fish, and (6) water temperature. To detect seasonal and annual trends in fish assemblages in reference sites, we rely on repeated and consistent annual sampling at each monitoring site. The general rationale for the repeated sampling of reference sites is to ensure that we account for the high interannual variability in fish

  5. Covariation of viral parameters with bacterial assemblage richness and diversity in the water column and sediments

    Science.gov (United States)

    Hewson, Ian; Fuhrman, Jed A.

    2007-05-01

    Viruses are hypothesized to maintain diversity in microbial assemblages by regulating the abundance of dominant competitors and thereby allowing less-dominant competitors to persist in assemblages; however, there have been few empirical data sets to support this idea. In this study, we examined the relationship between the ratio of viral abundance to bacterial abundance, viral production, and the relative richness and diversity of bacterial assemblage fingerprints, in samples taken from geographically widespread locations (North Pacific gyre, the Amazon River plume and adjacent North Atlantic gyre, Gulf of Mexico, Southern California Bight and Arafura—Coral Seas) which are oligo- to mesotrophic. Bacterial assemblage richness and diversity as measured by automated rRNA intergenic spacer (ARISA) fingerprinting were significantly and positively correlated with the ratio of virus abundance to bacteria abundance (VBR) and to the rate of virus production only in the oligotrophic North Pacific gyre. ARISA fingerprint richness/diversity were not significantly correlated to viral parameters when assessed across all samples in surface waters, suggesting there is not a singular global quantitative relationship between viral pressure and host diversity within well evolved host/virus systems in different geographic locations in plankton. In sediments off Southern California, viral parameters significantly and negatively correlated with ARISA diversity, suggesting strong viral interactions in this habitat. To examine covariation of viral parameters and the relative abundance and diversity of rarer bacterial taxa (i.e., less-dominant competitor), the richness and diversity of diazotroph communities was measured using terminal restriction fragment length polymorphism (TRFLP) of a portion ( nifH) of the nitrogenase gene. The richness and diversity of diazotrophic communities were significantly and negatively correlated with viral parameters across all locations. Since diazotrophs

  6. The Fish Assemblage of a Newfoundland Estuary: Diel, Monthly and Annual Variation

    Science.gov (United States)

    Methven, D. A.; Haedrich, R. L.; Rose, G. A.

    2001-06-01

    Twice monthly sampling over two 16 month periods at a shallow site on Newfoundland's east coast showed the fish assemblage to be dominated by four taxa ( Gasterosteus aculeatus, G. wheatlandi, Osmerus mordax, Gadus spp.) that accounted for 96% of the individuals collected. Of the 16 479 fish measured, 65% were adults based on the estimated size of first spawning. The fish assemblage was dominated (86%) by species with demersal eggs, several of which spawn at the same shallow sites used by juveniles as nursery sites. Coastal spawning and demersal eggs maintain offspring in coastal nursery areas where survival is thought to be increased. Number of species and number of fish were both correlated with water temperature being highest from mid-summer to early autumn and lowest in winter. Temperature, time of spawning, and movements of juveniles and adults facilitated grouping species into five assemblages based on seasonal abundance: seasonal periodic species (summer and winter), regular species, regular species collected in all seasons except winter, and occasional (rare) species. At the diel scale, two consistent species groupings were observed: species that showed no significant difference between day and night and species caught primarily at night. Number of night species exceeded day species by a factor of two. No seine-caught species in shallow water exhibited significantly higher catches during the day. Observations by SCUBA divers indicated some species were more abundant during day time at slightly deeper depths. This observation in conjunction with day and night seining in shallower water, suggests these species aggregate in deeper water during day and move to shallow waters at night.

  7. Greenhouse gas emissions from dung pats vary with dung beetle species and with assemblage composition.

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    Irene Piccini

    Full Text Available Cattle farming is a major source of greenhouse gases (GHGs. Recent research suggests that GHG fluxes from dung pats could be affected by biotic interactions involving dung beetles. Whether and how these effects vary among beetle species and with assemblage composition is yet to be established. To examine the link between GHGs and different dung beetle species assemblages, we used a closed chamber system to measure fluxes of carbon dioxide (CO2, methane (CH4 and nitrous oxide (N2O from cattle dung pats. Targeting a total of four dung beetle species (a pat-dwelling species, a roller of dung balls, a large and a small tunnelling species, we ran six experimental treatments (four monospecific and two mixed and two controls (one with dung but without beetles, and one with neither dung nor beetles. In this setting, the overall presence of beetles significantly affected the gas fluxes, but different species contributed unequally to GHG emissions. When compared to the control with dung, we detected an overall reduction in the total cumulative CO2 flux from all treatments with beetles and a reduction in N2O flux from the treatments with the three most abundant dung beetle species. These reductions can be seen as beneficial ecosystem services. Nonetheless, we also observed a disservice provided by the large tunneler, Copris lunaris, which significantly increased the CH4 flux-an effect potentially traceable to the species' nesting strategy involving the construction of large brood balls. When fluxes were summed into CO2-equivalents across individual GHG compounds, dung with beetles proved to emit less GHGs than did beetle-free dung, with the mix of the three most abundant species providing the highest reduction (-32%. As the mix of multiple species proved the most effective in reducing CO2-equivalents, the conservation of diverse assemblages of dung beetles emerges as a priority in agro-pastoral ecosystems.

  8. Arthropod diversity and assemblage structure response to deforestation and desertification in the Sahel of western Senegal

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    Brandon J. Lingbeek

    2017-07-01

    Full Text Available Drylands are highly vulnerable to desertification and among the most endangered ecosystems. To understand how biodiversity responds to environmental degradation in these fragile ecosystems, we examined whether arthropod, beetle, spider and ant diversity and assemblage structure differed (1 between seasons, (2 among locations (3 between protected areas of tropical dry forest and adjacent communal lands suffering from desertification, as well as (4 how vegetation impacts assemblage structures. We established 12 plots spaced homogenously throughout each protected area and the adjacent communal land at three locations: Beersheba, Bandia and Ngazobil. Within each plot, we measured canopy closure, vegetation height, percent cover of bare ground, leaf litter, grasses and forbs and collected arthropods using pitfall traps during the 2014 dry (May and rainy (September seasons. We collected 123,705 arthropods representing 733 morphospecies, 10,849 beetles representing 216 morphospecies, 4969 spiders representing 91 morphospecies and 59,183 ants representing 45 morphospecies. Results showed greater arthropod and beetle diversities (P = 0.002–0.040 in the rainy season, no difference in diversity among locations for any taxonomic group and a difference (P ≤ 0.001 in diversity for all taxa between protected areas and communal lands. Assemblage structures of all taxa responded (P = 0.001 to vegetation characteristics, differed (P = 0.015–0.045 between seasons and, with a few exceptions, locations and fragments. Our results illustrate the importance of a multi-taxa approach in understanding biodiversity response to anthropogenic disturbances as well as the value of protected areas in preserving biodiversity of the Sahel.

  9. Faunistic assemblages of a sublittoral coarse sand habitat of the northwestern Mediterranean

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    Eva Pubill

    2011-02-01

    Full Text Available The sublittoral megabenthic assemblages of a northwestern Mediterranean coarse sandy beach exploited for the bivalve Callista chione were studied. The spatial and bathymetric variability of its distinctive faunal assemblages was characterised by quantitative sampling performed with a clam dredge. The taxa studied were Mollusca Bivalvia and Gastropoda, Crustacea Decapoda, Echinodermata and Pisces, which accounted for over 99% of the total biomass. Three well-differentiated species assemblages were identified: (1 assemblage MSS (Medium Sand Shallow in medium sand (D50=0.37 mm and shallow waters (mean depth =6.5 m, (2 assemblage CSS (Coarse Sand Shallow in coarse sand (D50=0.62 mm in shallow waters (mean depth =6.7 m, and (3 assemblage CSD (Coarse Sand Deep in coarse sand (D50=0.64 mm in deeper waters (mean depth =16.2 m. Assemblage MSS was characterised by the codominance of the bivalves Mactra stultorum and Acanthocardia tuberculata. C. chione was dominant in both density and biomass in assemblages CSS and CSD. The occurrence of the crab Thia scutellata also characterised assemblage CSS, whereas the occurrence of the sea urchin Echinocardium mediterraneum characterised assemblage CSD. A depth breaking point of around 10 m determined the discontinuity between assemblages CSS and CSD, which was related to the closure depth of the beaches in the study area. Species richness was highest in the coarse sand communities; however, Shannon-Wiener diversity and Pielou equitability indexes were higher in the shallow fine sand community.

  10. The assemblage composition and structure of swimming crabs (Portunoidea) in continental shelf waters of southeastern Brazil

    Science.gov (United States)

    Andrade, L. S.; Frameschi, I. F.; Costa, R. C.; Castilho, A. L.; Fransozo, A.

    2015-02-01

    Three regions along the Brazilian coast characterized by the occurrence of contrasting natural phenomena, such as upwellings and continental input, were surveyed to determine the composition and structure of the assemblage of swimming crabs. Twelve monthly collections were undertaken (July 2010 to June 2011) in Macaé, Rio de Janeiro (MAC); Ubatuba, São Paulo (UBA); and São Francisco do Sul, Santa Catarina (SFS). The lowest values ​​of the phi sediment grain size measure, bottom temperature and the highest values of organic matter and salinity were measured in MAC. In all, 10,686 individuals were collected, belonging to six species of Portunoidea: Arenaeus cribrarius, Callinectes danae, Callinectes ornatus, Callinectes sapidus, Achelous spinicarpus and Achelous spinimanus. A Multiple Response Permutation Procedure (MRPP) test indicated that the species composition differed significantly among the sampling sites, showing substantial heterogeneity in the composition and abundance of species among regions. The results suggest that C. danae was more abundant in waters with lower salinity and lower organic matter content. In contrast, A. spinimanus is positively correlated with these factors, showing a greater abundance under the opposite conditions. Callinectes ornatus appeared not to show strong selectivity for particular habitat characteristics. We conclude from these findings that areas affected by different phenomena produce changes in the composition and abundance of the assemblage of Portunoidea. Although the strength of eutrophication differs between UBA and MAC, the substantial continental inflow affecting SFS favors the development of species that complete their life cycle in the estuary.

  11. Movers and stayers: Novel assemblages in changing environments

    Science.gov (United States)

    Hobbs, Richard L.; Valentine, Leonie E.; Standish, Rachel J.; Jackson, Stephen T.

    2018-01-01

    How species will respond to ongoing climate and other change is of increasing concern.Most attention is given to how species move or are moved, but many species stay.Understanding the dynamics of new species combinations is essential for successful conservation in a changing climate.Increased attention to species movement in response to environmental change highlights the need to consider changes in species distributions and altered biological assemblages. Such changes are well known from paleoecological studies, but have accelerated with ongoing pervasive human influence. In addition to species that move, some species will stay put, leading to an array of novel interactions. Species show a variety of responses that can allow movement or persistence. Conservation and restoration actions have traditionally focused on maintaining or returning species in particular places, but increasingly also include interven