Biodiversity of macrozoobenthos in a large river, the Austrian Danube, including quantitative studies in a free-flowing stretch below Vienna: a short review

The Danube is ca. 2850 km in length and is the second largest river in Europe. The Austrian part of the Danube falls 156 metres in altitude over its 351 km length and, since the early 1950s, the river has been developed into a power-generating waterway, so that the continuity of the river is now interrupted by ten impounded areas. Only two stretches of the original free-flowing river are left, the Wachau region (above river-km 2005, west of Vienna) and the region downstream from the impoundment at Vienna (river-km 1921). Most of the recent theories and concepts related to invertebrates, in the context of the ecology of running waters, are based on studies on small streams, whereas investigations of large rivers have played a minor role for a long time, mainly due to methodological difficulties. The authors' recent detailed studies on macroinvertebrates in the free-flowing section of the Danube below Vienna, provide an excellent opportunity to survey or restate scientific hypotheses on the basis of a large river. In this review the main interest focuses on the investigation of biodiversity, i.e. the number of species and their relative proportions in the whole invertebrate community, as well as major governing environmental factors. The article summarises the species composition, the important environmental variables at the river cross-section and the effect of upstream impoundment on the riverbed and its fauna

Ecosystem study Altenwoerth: impacts of a hydroelectric power-station on the River Danube in Austria

The aim of this article is to briefly describe the effects of the Altenwoerth Barrage, on the River Danube, on some physical variables and their consequent effects on water chemistry and the biota of the river. The methods used for biological sampling are summarised, especially those used in the limnological part of the study, and the macroinvertebrate and fish fauna listed. Comparisons are then made between the impounded section of river immediately above the dam and two unimpounded free-flowing sections of the river. Further developments on the Danube are considered

Eggs of Ephemeroptera

Information on fecundity, oviposition behaviour, egg hatching, and parthenogenetic development of Ephemeroptera is reviewed and summarized

Biodiversity of macrozoobenthos in a large river, the Austrian Danube, including quantitative studies in a free-flowing stretch below Vienna: a short review

The Danube is ca. 2850 km in length and is the second largest river in Europe. It rises in the Black Forest of Germany and discharges into the Black Sea (Romania and Ukraine). The catchment includes 12 other countries: Switzerland, Austria, Czech Republic, Slovakia, Hungary, Slovenia, Croatia, Bosnia/Herzegovina, Serbia & Montenegro, Albania, Bulgaria and Moldova (Fig. 1), and nearly 90 million people live in the catchment area of ca. 805 300 km2..These numbers illustrate and emphasise the enormous international importance of this river

Ecosystem study Altenworth: impacts of a hydroelectric power-station on the River Danube in Austria

The Danube, with a length of c. 2850 km, is the second largest river inEurope. It rises in the Black Forest (Germany), discharges into the BlackSea (Romania, former USSR) and crosses five other countries: Austria,Czechoslovakia, Hungary, former Yugoslavia, and Bulgaria (Fig. 1). Nearly90 million people live in its catchment area of c. 805 300 km². Includingits tributaries, twelve countries and about 447 million people are linked tothe Danube. These figures show the extraordinary internationalimportance of this river

Life history, seasonal variation and production of Andesiops torrens (Lugo-Ortiz and McCafferty) and Andesiops peruvianus (Ulmer) (Ephemeroptera: Baetidae) in a headwater Patagonian stream

Life history descriptors of mayfly species are increasingly used in ecological assessment studies as indicator of environmental stress and also to evaluate the potential effects of climate change. We investigated the life history, annual production and competition of two congeneric mayflies: Andesiops torrens and Andesiops peruvianus in a Patagonian mountain headwater stream (La Hoya). From July 2004 to June 2005 a monthly sampling was conducted at riffle areas using a Surber net. Mean density of A. torrens ranged from 26 to 1080indm-2 whereas that of A. peruvianus ranged from 7 to 629indm-2. The annual production and P/B ratios of A. torrens (0.18gm-2, 3.90) and A. peruvianus (0.11gm-2, 3.35) at La Hoya stream were low, but within the expected values for cold water environments at high elevations. The two species had a similar larval life history with small larvae predominating in late summer and early autumn, middle size larvae being represented throughout winter, and mature larvae and emergence occurring in summer. As a result A. torrens and A. peruvianus showed moderately synchronized univoltine life cycles. The temporal interspecific overlap on both density and biomass was very low. This suggests that these two species of grazers reduce the competition for resources by having a marked temporal segregation.Fil: Epele, Luis Beltran. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Miserendino, Maria Laura. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pessacq, Pablo. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Combining literature-based and data-driven fuzzy models to predict brown trout (salmo trutta l.) spawning habitat degradation induced by climate change

[EN] A fuzzy rule-based system combining empirical data on hydraulic preferences and literature information on temperature requirements was used to foresee the brown trout (Salmo trutta L.) spawning habitat degradation induced by climate change. The climatic scenarios for the Cabriel River (Eastern Iberian Peninsula) corresponded to two Representative Concentration Pathways (4.5 and 8.5) for the short (2011¿2040) and mid (2041¿2070) term horizons. The hydraulic and hydrologic modelling were undertaken with process-based numerical models (i.e., River2D© and HBV-light) while the water temperature was modelled by assembling the predictions of three machine learning techniques (M5, Multi-Adaptive Regression Splines and Support Vector Regression). The predicted rise in the water temperature will not be compensated by the more benign lower flows. Consequently, the suitable spawning habitat will be reduced between 15.4¿48.7%. The entire population shall suffer the effects of climate change and will probably be extirpated from the downstream segments of the river.The study has been partially funded by the IMPADAPT project (CGL2013-48424-C2-1-R) with Spanish MINECO (Ministerio de Economía y Competitividad) and FEDER funds and by the Confederación Hidrográfica del Júcar (Spanish Ministry of Agriculture, Food and Environment). The authors thank AEMET and UC for the data provided for this work (dataset Spain02). Finally, we are grateful to the colleagues who worked in the field and in preliminary data analyses; especially Marcello Minervini (funded by the EU programme of Erasmus Traineeships, at the Dept. of Hydraulic Engineering and Environment, Universitat Politècnica de València).Muñoz Mas, R.; Marcos-García, P.; Lopez-Nicolas, A.; Martínez-García, F.; Pulido-Velazquez, M.; Martinez-Capel, F. (2018). Combining literature-based and data-driven fuzzy models to predict brown trout (salmo trutta l.) spawning habitat degradation induced by climate change. Ecological Modelling. 386:98-114. https://doi.org/10.1016/j.ecolmodel.2018.08.012S9811438

Sensitivity of the early life stages of a mayfly to fine sediment and orthophosphate levels

The ecological effects of interacting stressors within lotic ecosystems have been widely acknowledged. In particular, the ecological effects of elevated fine sediment inputs and phosphate have been identified as key factors influencing faunal community structure and composition. However, while knowledge regarding adult and larval life stage responses to environmental stressors has grown, there has been very limited research on their eggs. In this study, the eggs of the mayfly Serratella ignita (Ephemerellidae: Ephemeroptera) were collected and incubated in laboratory aquaria to hatching under differing concentrations of inert suspended sediment (SS) and orthophosphate (OP), individually and in combination. Results indicate that SS and OP have greater effects on egg hatching in combination than when either were considered in isolation. SS displayed a greater effect on egg survival than OP in isolation or when OP was added to elevated SS treatments. Egg mortality in control treatments was around 6% compared to 45% in treatments with 25 mg 1⁻¹ SS and 52% in 0.3 mg 1⁻¹ OP treatments. Even relatively modest levels of each stressor (10 mg 1⁻¹ SS; 0.1 mg 1⁻¹ OP), below national legal thresholds, had significant effects on egg survival to hatching. The results support calls for legal levels of SS to be reassessed and suggest that more research is required to assess the impacts of pollution on invertebrate egg development given their different sensitivity and exposure pathways compared to other life stages

Quantitative Charakterisierung der Lebensgemeinschaft in Fliessgewässern und ihre Abhängigkeit von Umweltvariablen

Anhand der Beziehung zwischen der Struktur des Lebensraumes und der Besiedlungsstruktur der Massenformen der Tiergemeinschaft bei Stromkilometer 2005 der Donau, des Schlüpfens aus dem Ei von zehn Steinfliegenarten und des Lebenszyklus einer Köcherfliegenart wird gezeigt welche Voraussetzungen erfüllt werden müssen, um das wissenschaftliche Management für Fließgewässer weiterentwickeln zu können.1051181