The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform

Nikolai Friberg - One of the best experts on this subject based on the ideXlab platform.

  • stream macroinvertebrate occurrence along gradients in organic pollution and eutrophication
    Freshwater Biology, 2009
    Co-Authors: Nikolai Friberg, Jens Skriver, Soren Ejling Larsen, Morten Lauge Pedersen, Andrea Buffagni
    Abstract:

    SUMMARY 1. 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 Danish monitoring programme on the aquatic environment. Macroinvertebrate communities were sampled in spring using a standardised kick-sampling procedure whereas chemical variables were sampled six to 24 times per year per site. Habitat variables were assessed once when macroinvertebrates were sampled. 2. The plecopteran Leuctra showed a significant negative exponential relationship (r 2 = 0.90) with BOD5 and occurred at only 16% of the sites with BOD5 above 1.6 mg L )1 . Sharp declines with increasing BOD5 levels were found for the trichopteran families Sericostomatidae and Glossosomatidae although they appeared to be slightly less sensitive than Leuctra. Other plecopterans such as Isoperla showed a similar type of response curve to Leuctra (negative exponential) but occurred at sites with relatively high concentrations of BOD5 up to 3–4 mg L )1 . In contrast, the response curve of the isopod Asellus aquaticus followed a saturation function reaching a plateau above 3–4 mg L )1 BOD5 and the dipteran Chironomus showed an exponential increase in occurrence with increasing BOD5 concentration. 3. Macroinvertebrate occurrence appeared to be related primarily to concentrations of BOD5 ,N H 4–N and total-P whereas there were almost no relationships to total-N. Occurrence of a number of taxa showed a stronger relationship to habitat conditions (width and substrate) than chemical variables. 4. Important macroinvertebrate taxa are reduced at concentrations of BOD5 that are normally perceived as indicating unimpacted stream site conditions. Our results confirmed sensitivity/tolerance patterns used by existing bioassessment systems only to some degree.

  • stream macroinvertebrate drift response to pulsed exposure of the synthetic pyrethroid lambda cyhalothrin
    Environmental Toxicology, 2005
    Co-Authors: Rasmus B Lauridsen, Nikolai Friberg
    Abstract:

    Outdoor experimental channels were used to study the behavioral changes of stream macroinvertebrates exposed to a pulse of the pyrethroid insecticide lambda-cyhalothrin. The primary end point was the number of macroinvertebrates drifting, but the mobility of macroinvertebrates caught in the drift also was assessed. A specified number of two insect species, Baetis rhodani and Leuctra fusca/digitata, and of the amphipod Gammarus pulex were introduced into small replicated subsections of the experimental channels. Macroinvertebrates were allowed to acclimatize for 26 h prior to a 60-min pulsed exposure to lambda-cyhalothrin. Measurement was initiated 2 h before pesticide application and continued for the following 24 h. Pulse concentrations of lambda-cyhalothrin of 0.001, 0.01, 0.1, and 1.0 microg L(-1) were applied, and each experiment was replicated 8 times. All three species responded to the pesticide pulse with catastrophic drift. The 0.001 microg L(-1) treatment caused a significant increase in the drift of Gammarus, whereas the drift response threshold was 0.01 microg L(-1) for the two insect species. Drift response onset followed the applied pulse concentration, with the highest concentrations resulting in more individuals of all species entering drift at an early stage. The majority of individuals caught in drift samples during low concentrations showed no change in mobility. At the two highest concentrations, however, both Baetis and Leuctra were in the process of being immobilized, with Leuctra the more sensitive of the two. In contrast, only a few of the Gammarus individuals caught showed changes in mobility after the high-concentration treatments. The present study shows that lambda-cyhalothrin is a potential hazard for macroinvertebrate populations in headwater streams. The clear species-specific responses indicate that sublethal doses have the potential to change the macroinvertebrate community structure.

  • Stream macroinvertebrate drift response to pulsed exposure of the synthetic pyrethroid lambda‐cyhalothrin
    Environmental toxicology, 2005
    Co-Authors: Rasmus B Lauridsen, Nikolai Friberg
    Abstract:

    Outdoor experimental channels were used to study the behavioral changes of stream macroinvertebrates exposed to a pulse of the pyrethroid insecticide lambda-cyhalothrin. The primary end point was the number of macroinvertebrates drifting, but the mobility of macroinvertebrates caught in the drift also was assessed. A specified number of two insect species, Baetis rhodani and Leuctra fusca/digitata, and of the amphipod Gammarus pulex were introduced into small replicated subsections of the experimental channels. Macroinvertebrates were allowed to acclimatize for 26 h prior to a 60-min pulsed exposure to lambda-cyhalothrin. Measurement was initiated 2 h before pesticide application and continued for the following 24 h. Pulse concentrations of lambda-cyhalothrin of 0.001, 0.01, 0.1, and 1.0 microg L(-1) were applied, and each experiment was replicated 8 times. All three species responded to the pesticide pulse with catastrophic drift. The 0.001 microg L(-1) treatment caused a significant increase in the drift of Gammarus, whereas the drift response threshold was 0.01 microg L(-1) for the two insect species. Drift response onset followed the applied pulse concentration, with the highest concentrations resulting in more individuals of all species entering drift at an early stage. The majority of individuals caught in drift samples during low concentrations showed no change in mobility. At the two highest concentrations, however, both Baetis and Leuctra were in the process of being immobilized, with Leuctra the more sensitive of the two. In contrast, only a few of the Gammarus individuals caught showed changes in mobility after the high-concentration treatments. The present study shows that lambda-cyhalothrin is a potential hazard for macroinvertebrate populations in headwater streams. The clear species-specific responses indicate that sublethal doses have the potential to change the macroinvertebrate community structure.

Rasmus B Lauridsen - One of the best experts on this subject based on the ideXlab platform.

  • stream macroinvertebrate drift response to pulsed exposure of the synthetic pyrethroid lambda cyhalothrin
    Environmental Toxicology, 2005
    Co-Authors: Rasmus B Lauridsen, Nikolai Friberg
    Abstract:

    Outdoor experimental channels were used to study the behavioral changes of stream macroinvertebrates exposed to a pulse of the pyrethroid insecticide lambda-cyhalothrin. The primary end point was the number of macroinvertebrates drifting, but the mobility of macroinvertebrates caught in the drift also was assessed. A specified number of two insect species, Baetis rhodani and Leuctra fusca/digitata, and of the amphipod Gammarus pulex were introduced into small replicated subsections of the experimental channels. Macroinvertebrates were allowed to acclimatize for 26 h prior to a 60-min pulsed exposure to lambda-cyhalothrin. Measurement was initiated 2 h before pesticide application and continued for the following 24 h. Pulse concentrations of lambda-cyhalothrin of 0.001, 0.01, 0.1, and 1.0 microg L(-1) were applied, and each experiment was replicated 8 times. All three species responded to the pesticide pulse with catastrophic drift. The 0.001 microg L(-1) treatment caused a significant increase in the drift of Gammarus, whereas the drift response threshold was 0.01 microg L(-1) for the two insect species. Drift response onset followed the applied pulse concentration, with the highest concentrations resulting in more individuals of all species entering drift at an early stage. The majority of individuals caught in drift samples during low concentrations showed no change in mobility. At the two highest concentrations, however, both Baetis and Leuctra were in the process of being immobilized, with Leuctra the more sensitive of the two. In contrast, only a few of the Gammarus individuals caught showed changes in mobility after the high-concentration treatments. The present study shows that lambda-cyhalothrin is a potential hazard for macroinvertebrate populations in headwater streams. The clear species-specific responses indicate that sublethal doses have the potential to change the macroinvertebrate community structure.

  • Stream macroinvertebrate drift response to pulsed exposure of the synthetic pyrethroid lambda‐cyhalothrin
    Environmental toxicology, 2005
    Co-Authors: Rasmus B Lauridsen, Nikolai Friberg
    Abstract:

    Outdoor experimental channels were used to study the behavioral changes of stream macroinvertebrates exposed to a pulse of the pyrethroid insecticide lambda-cyhalothrin. The primary end point was the number of macroinvertebrates drifting, but the mobility of macroinvertebrates caught in the drift also was assessed. A specified number of two insect species, Baetis rhodani and Leuctra fusca/digitata, and of the amphipod Gammarus pulex were introduced into small replicated subsections of the experimental channels. Macroinvertebrates were allowed to acclimatize for 26 h prior to a 60-min pulsed exposure to lambda-cyhalothrin. Measurement was initiated 2 h before pesticide application and continued for the following 24 h. Pulse concentrations of lambda-cyhalothrin of 0.001, 0.01, 0.1, and 1.0 microg L(-1) were applied, and each experiment was replicated 8 times. All three species responded to the pesticide pulse with catastrophic drift. The 0.001 microg L(-1) treatment caused a significant increase in the drift of Gammarus, whereas the drift response threshold was 0.01 microg L(-1) for the two insect species. Drift response onset followed the applied pulse concentration, with the highest concentrations resulting in more individuals of all species entering drift at an early stage. The majority of individuals caught in drift samples during low concentrations showed no change in mobility. At the two highest concentrations, however, both Baetis and Leuctra were in the process of being immobilized, with Leuctra the more sensitive of the two. In contrast, only a few of the Gammarus individuals caught showed changes in mobility after the high-concentration treatments. The present study shows that lambda-cyhalothrin is a potential hazard for macroinvertebrate populations in headwater streams. The clear species-specific responses indicate that sublethal doses have the potential to change the macroinvertebrate community structure.

Gilles Vinçon - One of the best experts on this subject based on the ideXlab platform.

  • toward a comprehensive coi dna barcode library for swiss stoneflies insecta plecoptera with special emphasis on the genus Leuctra
    Zoosymposia, 2016
    Co-Authors: Jeanluc Gattolliat, Gilles Vinçon, Sofia Wyler, Jan Pawlowski, Michel Sartori
    Abstract:

    The Swiss Barcode of Life initiative (SwissBOL) aims to inventory the genetic biodiversity in Switzerland using a short DNA sequence. DNA barcoding provides an additional tool for species identification that complements traditional morphological approaches. We report on the establishment of a DNA barcode library for Plecoptera, taxa that are of great importance as bioindicators of water quality and that often present difficulties in species-level identification for larvae and female specimens. Non-destructive DNA extraction, PCR amplification and sequencing of part of the mitochondrial gene Cytochrome Oxidase I (COI) was conducted for 440 individuals (one to eight per species) belonging to 90 species (of the 112 reported from Switzerland). Intra and interspecific distances were calculated and gene trees reconstructed. In most cases, COI was efficient in delimiting stonefly species. Some doubtful specimens were subsequently re-examined and a few misidentifications were found, especially in some problematic groups in the genus Leuctra Stephens, 1836. Larger genetic distances in some species (e.g. Leuctra nigra (Olivier 1811)) indicate the possible presence of sibling species, while in a few cases closely related species are genetically difficult to separate (within the Leuctra fusca species group).

  • Contribution to the knowledge of Turkish stoneflies with annotated catalogue (Insecta: Plecoptera).
    Zootaxa, 2016
    Co-Authors: Mustafa C. Darilmaz, Dávid Murányi, Ali Salur, Gilles Vinçon
    Abstract:

    The stoneflies of Turkey are reviewed providing all known distributions and including new records. Additionally, ecological and biogeographical notes are given. The genus Taeniopteryx Pictet 1841 is reported from Turkey for the first time and 12 species new for the Turkish fauna: Leuctra joosti Braasch 1970, L. kopetdaghi Zhiltzova 1972, Protonemura rauschi Theischinger 1975, P. strandschaensis Braasch & Joost 1972, Nemoura asceta Muranyi 2007 , N. cambrica Stephens 1836 , N. uncinata Despax 1934, Taeniopteryx caucasica Zhiltzova 1981, Brachyptera risi (Morton 1896), Pontoperla katherinae (Balinsky 1950), Siphonoperla neglecta (Rostock 1881), and Bulgaroperla mirabilis nigrita Zwick 1978. Protonemura bithynica Aubert 1964 and Nemoura turcica Zwick 1972 are recognized as full species. The previously unknown female of Leuctra marilouae Vincon & Sivec 2001 is described. The type locality is also given for each species located in Turkey. The distributions of several rare endemic species are augmented by additional new records ( Leuctra aculeata Zwick 1982, L. brachyptera Kazanci 1985, L. karcali Vincon & Sivec 2001, L. kurui Kazanci 1983, L. marilouae Vincon & Sivec 2001, L. sipahilerae Vincon & Sivec 2001, L. theischingeri Vincon & Sivec 2001, Protonemura bacurianica bacurianica Zhiltzova 1957, P. oreas Martynov 1928, P. spinulata Martynov 1928 (first confirmed records from Anatolia), P. triangulata Martynov 1928, Nemoura dromokeryx Theischinger 1976, N. martynovia Claassen 1936, and Brachyptera berkii Kazanci 2001. Several species previously reported only from females are excluded from the Turkish fauna: Leuctra minuta minuta Zhiltzova 1960, L. svanetica Zhiltzova 1960, P. dilatata Martynov 1928. Other species are also excluded from the Turkish fauna: L. fusca fusca (Linnaeus 1758), N. carpathica Illies 1963, Siphonoperla burmeisteri (Pictet 1841), and S. libanica Alouf, 1992. According to literature and our new faunistic data, 117 stonefly taxa representing 7 families and 24 genera are known from Turkey. Among them, 44 are endemic species from Anatolia.

  • TWO NEW ALPINE Leuctra IN THE L. BRAUERI SPECIES GROUP (PLECOPTERA, LEUCTRIDAE)
    2011
    Co-Authors: Gilles Vinçon, Wolfram Graf
    Abstract:

    Two new species of the genus Leuctra that were previously confused with L. braueri Kempny, 1898 are described from the eastern Alps: L. muranyii sp. n. and L. juliettae sp. n. A comparative description of L. braueri is given. The composition and characters of the L. braueri species group are discussed.

  • two new Leuctra species in the inermis group l garumna from the pyrenees and l ameliae from the western alps plecoptera leuctridae
    Aquatic Insects, 1996
    Co-Authors: Gilles Vinçon, Carlalberto Ravizza
    Abstract:

    Leuctra garumna sp. n., from the French and Spanish Pyrenees, and L. ameliae sp. n., from the French and Italian Western Alps are described and compared with the closely related L. kempnyi Mosely. To allow better separation, a new description of L. kempnyi is given.

  • CONTRIBUTION TO THE KNOWLEDGE OF PYRENEAN STONEFLIES: Leuctra ARIEGA SP. N. (INSECTA: PLECOPTERA)
    Aquatic Insects, 1995
    Co-Authors: Isabel Pardo, Gilles Vinçon
    Abstract:

    Leuctra ariega sp. n. from the central eastern Pyrenees is described. Morphological features and habitat characteristics are provided and discussed in relation to similar species of the genus Leuctra.

Murányi Dávid - One of the best experts on this subject based on the ideXlab platform.

Vinçon Gilles - One of the best experts on this subject based on the ideXlab platform.