Benthic invertebrate neozoa in Austrian rivers

Neozoa werden als gebietsfremde Arten definiert, welche nach 1492 direkt oder indirekt durch den Menschen eingeführt wurden und selbstreproduzierende Populationen zu bilden im Stande sind (Essl & Rabitsch 2002). Biologische Invasionen sind schon seit dem Zeitalter des Kolonialismus ein bekanntes Phänomen, gegenwärtig hat das Problem in einer Zeit der Globalisierung von Wirtschaft und Tourismus und einer globalen Klimaveränderung jedoch eine neue Dimension und Geschwindigkeit erreicht. In Österreich gibt es grundsätzlich eine gute Datenbasis über das Auftreten von benthischen Einwanderern. Bereits in der älteren Literatur findet man dazu einige Hinweise, z.B.: Strouhal (1939), Vornatscher (1965) und Liepolt (1965–67). Größere Aufmerksamkeit wurde dem Phänomen invasiver Arten seit der massiven Ausbreitung der Dreikantmuschel Dreissena polymorpha geschenkt, als sich diese in den 1970er Jahren in vielen Flüssen und Seen in einem sehr kurzen Zeitraum ausbreitete. Verstärkte Beachtung wurde den Neozoa in der Limnologie aber erst im letzten Jahrzehnt zuteil, als die Fundnachweise immer häufiger wurden und sowohl ökonomische als auchbemerkenswerte ökologische Auswirkungen durch invasive Arten vermutet oder nachgewiesen wurden. Beispielsweise belegte Gruber (2006), dass der autochthone Steinkrebs (Austropotamobius torrentium) bereits bis in die Quellregion hinein durch den amerikanischen Signalkrebs (Pacifastacus leniusculus) verdrängt wird. In Österreich entstand als Folge des erhöhten Problembewusstseins in den letzten Jahren eine Reihe von umfassenden Publikationen zum Thema Neobiota: „Invaders“ (Aescht & al. 1995), „Neobiota in Österreich“ (Essl & Rabitsch 2002) und „Aliens“ (Wallner 2005). Während die überwiegende Zahl der Publikationen zum Thema Neozoa von taxonomischen Fachspezialisten stammt und deshalb zumeist auf eine oder einige ausgewählte Tiergruppen beschränkt bleibt, basiert vorliegender Beitrag auf Monitoringdaten und gewässerökologischen Untersuchungen, in welchen immer die gesamte Artengesellschaft der benthischen Evertebraten erhoben wurde.Based on 9,544 data sets from 1,060 Austrian rivers and streams the paper gives a quantitative and qualitative overview of the occurrence and distribution of benthic invertebrate neozoa in Austrian running waters. Excluding those species that have been recorded only as single findings or which inhabit greenhouses with no connection to natural water bodies, a total number of 46 benthic invertebrate species can be classified as neozoa for Austria. Referred to the known number of about 3,200 benthic macro-invertebrate species the neozoa fauna comprises only a small amount of 1.8 %. On the other hand these neozoa colonise 16.1% of the investigated water bodies. Most investigation sites are inhabited by only one neozoa species. The maximum number of neozoa species found at one investigation site was not higher than 13. However, at some river sites the abundance of neobiota specimens can clearly dominate the benthic community. E. g. a maximum number of about 500,000 Corophium curvispinum individuals per m² (99% of the total abundance) with a biomass up to 0.6 kg fresh weight per m² has been observed in the River Morava (Lower Austria), a neozoa biomass of 7 kg/m2 (Corbicula fluminea) was documented in a muddy Danube harbour at Linz, Upper Austria. In contrast to the indigenous fauna, which is mainly composed of insects (85%) the neozoa fauna is dominated by Crustacea (53%) and Mollusca (24%). 47% of the neozoa species originate from European regions, mainly the ponto-caspian area. Other important donor areas are North America and South East Asia. With respect to aquatic neozoa in Austria, the River Danube can be clearly identified as the main immigration channel of the ponto-caspian (most of the Mollusca and Crustacea neobiota species) as well as the mediterranean fauna (Atyaephyra desmaresti) and other species that spread via Western Europe, respectively. Although most of the benthic invertebrate neozoa have never left the main Danube channel, a steady immigration from Danube tributaries by some species has been observed in the last years

A trait-based approach to assess the vulnerability of European aquatic insects to climate change

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Drusus chrysotus (Rambur, 1842) (Trichoptera: Limnephilidae: Drusinae), nova vrsta tulara za faunu Hrvatske

Drusus chrysotus is a cold water stenotherm species inhabiting spring reaches and headwaters of mountain streams. It has a disjunct distribution range covering mountain ranges across central Europe, and has now been recorded for the first time in Croatia, in the Gorski kotar region, thus extending its distribution range to the Dinaric Western Balkan ecoregion (sensu Illies, 1978). D. chrysotus was collected at the spring of the Dobra River, which is heavily impacted by human activity. Due to the specific aquatic insect fauna of this spring, conservation and prevention of further habitat alteration of this section of the river Dobra River should be a priority for the local community.Vrsta Drusus chrysotus je stenoterm koji naseljava hladne vodotokove, tj. izvore i izvorišne dijelove planinskih potoka. Ima disjunktni areal i rasprostranjena je u planinskim područjima Središnje Europe. Sada je prvi puta zabilježena u Hrvatskoj, u Gorskom kotaru, što predstavlja proširenje njezinog areala na ekoregiju Dinaridski zapadni Balkan (sensu Illies). Vrsta D. chrysotus prikupljena je na izvoru Dobre, koji je pod jakim antropogenim utjecajem te je značajno izmijenjen. Obzirom na vrlo specifičnu faunu vodenih kukaca ovog izvora, zaštita i sprječavanje daljnje degradacije staništa izvorišnog dijela rijeke Dobre trebala bi biti jedan od prioriteta lokalne uprave

Flow amplitude or up‐ramping rate? : quantifying single and combined effects on macroinvertebrate drift during hydropeaking simulations, considering sensitive traits

The hydrological regime of many alpine rivers is heavily altered due hydroelectric power generation. Hydropeaking operation produces frequent and irregular discharge fluctuations. Depending on the operational changes of flow amplitude and/or upramping rate as well as on river morphology, hydropeaking can lead to quick and strong variations in hydraulic stress affecting stream invertebrates and causing increased drift. In the present flume experimental study, we analyzed trait-specific drift reactions to single and combined effects of increased flow amplitude and upramping rate. We analyzed taxa according to their hydraulic habitat preference and flow exposure, as these traits seem to be indicative toward hydropeaking. The results show that the sudden increase in discharge and related flow velocity led to increased macroinvertebrate drift proportions in hydropeaking treatments, which differed significantly to parallel control runs (mean drift proportion in all hydropeaking setups: 13% compared to 5% in controls). Increasing flow amplitudes led to an increase in drift for most taxa and traits. This was particularly significant for taxa associated with lentic areas. The effect of the up-ramping rate on macroinvertebrate drift was nonsignificant but showed strong interactive effects with the flow amplitude, especially for taxa dwelling on the substrate surface. Our results therefore indicate that dischargerelated parameters, such as flow velocity, primarily affect macroinvertebrate drift and the importance of the up-ramping rate increases, if certain discharge-related thresholds are exceeded. Vice versa, a reduction of the up-ramping rate at hydropeaking events with high flow amplitudes may reduce the effect on macroinvertebrate drift. Flow-exposed (surface) and flow-sensitive (lentic) taxa showed distinct drift reactions following hydropeaking treatments, which were significantly higher compared to effects on taxa associated to lotic and interstital habitats. Therefore, we conclude that both traits (hydraulic and vertical habitat preference) have proven as promising for analyzing hydropeaking effects. The trait classifications should be extended to a higher number of taxa and to different life stages as these may show different drift patterns

Microbial faecal pollution of river water in a watershed of tropical Ethiopian highlands is driven by diffuse pollution sources

Journal of Water and HealthTropical communities in the developing world depend heavily on riverine systems for their socioeconomic development. However, these resources are poorly protected from diffuse pollution, and there is a lack of quantitative information regarding the microbial pollution characteristics of riverine water, despite frequently reported gastrointestinal diseases. The aim of our study was to apply faecal taxation (i.e., faecal pellet counting in representative test areas to estimate the potential availability of diffuse pollution sources) in combination with a detailed microbiological faecal pollution analysis in a riverine environment to elucidate the importance of diffuse pollution. To realize this approach, ambient faecal pellets, a multiparametric data set for standard faecal indicator bacteria (SFIB), including Escherichia coli, Clostridium perfringens spores and enterococci from catchment soil and river water, and a number of riverine water physicochemical variables were analysed during a one-year cycle. We demonstrated that the abundance of ambient faecal pellets, which were consistently counted at reference sites in the catchment, was associated with faecal pollution in the river water. Water SFIB, dissolved oxygen, nutrients, conductivity and total suspended solids were strongly linked with the abundance of ambient faecal pellets in the river catchment, as demonstrated by principal component analysis (PCA). Elevated concentrations of SFIB in the riverine water in the absence of rainfall also suggested the direct input of faecal bacteria into the riverine water by livestock (e.g., during watering) and humans (e.g., during bathing). Statistical analyses further revealed that the microbiological water quality of the investigated riverine water was not influenced by SFIB potentially occurring in the soil. This study demonstrates the importance of diffuse faecal pollution sources as major drivers of the microbiological quality of riverine water in the Ethiopian highlands. In addition, the new successfully applied integrated approach could be very useful for developing predictive models, which would aid in forecasting riverine microbiological quality in tropical developing countriesinfo:eu-repo/semantics/publishedVersio

Das Zeitschriften-Paradoxon oder: Wer verfügt über wissenschaftliche Information?

Inhalt: Stephan, Werner: Begrüßung und Einführung - Graf, Bernhard: Zeitschriftenevaluation an der Universität Stuttgart. Ist die inhaltliche Bewertung ein hinreichendes Kriterium für Zeitschriftenabbestellungen? Ein Werkstattbericht - Kirchgässner, Adalbert: 13 Jahre Zeitschriftenabbestellungen an der Universität Konstanz. Die Auswirkungen der Preissteigerungen bei stagnierenden Etats auf das Zeitschriftenportfolio. Veränderungen des Nutzerverhaltens und Konsequenzen für die künftige Bestandspolitik (in einem einschichten System) - Laschat, Sabine: Braucht die Wissenschaft noch Zeitschriften? - Schüz, Wolfram: Das Zeitschriftenparadoxo

Correction to: Niche differentiation among invasive Ponto-Caspian Chelicorophium species (Crustacea, Amphipoda, Corophiidae) by food particle size

A calibration mistake caused systematic error in the microscopic measurements; all filter mesh size values should be divided by a factor of 2.56. As our conclusions were based on the inter- and intraspecific variations of the trait, this systematic error does not influence them in any way

Niche differentiation among invasive Ponto-Caspian Chelicorophium species (Crustacea, Amphipoda, Corophiidae) by food particle size

After Chelicorophium curvispinum, two other Ponto-Caspian tube-dwelling, filter-feeding amphipod species (Chelicorophium robustum and Chelicorophium sowinskyi) have colonized several catchments in Central and Western Europe in recent decades. To reveal the mechanism of niche differentiation among them, we measured the mesh sizes of their filtering apparatus and analyzed multi-habitat sampling data from the River Danube using RDA-based variance partitioning between environmental and spatial explanatory variables. Morphometric data showed a clear differentiation among the species by filter mesh size (C. curvispinum > C. robustum > C. sowinskyi). Field data also indicated the relevance of suspended matter; however, the mere quantity of suspended solids included in the analysis could not explain the abundance patterns effectively. Current velocity, substrate types, and total nitrogen content also had a non-negligible effect; however, their role in the niche differentiation of the species is not evident. In summary, differences in their filter mesh sizes indicate a niche differentiation by food particle size among the invasive Chelicorophium species, allowing their stable coexistence given sufficient size variability in their food source. Consequently, the two recent invaders increase the effectiveness of resource utilization, resulting in a more intensive benthic–pelagic coupling in the colonized ecosystems

Molecular association and morphological characterisation of Himalopsyche larval types (Trichoptera, Rhyacophilidae)

Himalopsyche Banks, 1940 (Trichoptera, Rhyacophilidae) is a genus of caddisflies inhabiting mountain and alpine environments in Central and East Asia and the Nearctic. Of 53 known species, only five species have been described previously in the aquatic larval stage. We perform life stage association using three strategies (GMYC, PTP, and reciprocal monophyly) based on fragments of two molecular markers: the nuclear CAD, and the mitochondrial COI gene. A total of 525 individuals from across the range of Himalopsyche (Himalayas, Hengduan Shan, Tian Shan, South East Asia, Japan, and western North America) was analysed and 32 operational taxonomic units (OTUs) in our dataset delimited. Four distinct larval types of Himalopsyche are uncovered, and these are defined as the phryganea type, japonica type, tibetana type, and gigantea type and a comparative morphological characterisation of the larval types is presented. The larval types differ in a number of traits, most prominently in their gill configuration, as well as in other features such as setal configuration of the pronotum and presence/absence of accessory hooks of the anal prolegs