Christian Scheder

Conservation status of freshwater mussels in Europe: state of the art and future challenges.

Freshwater mussels of the Order Unionida provide important ecosystem functions and services, yet many of their populations are in decline. We comprehensively review the status of the 16 currently recognized species in Europe, collating for the first time their life‐history traits, distribution, conservation status, habitat preferences, and main threats in order to suggest future management actions. In northern, central, and eastern Europe, a relatively homogeneous species composition is found in most basins. In southern Europe, despite the lower species richness, spatially restricted species make these basins a high conservation priority. Information on freshwater mussels in Europe is unevenly distributed with considerable differences in data quality and quantity among countries and species. To make conservation more effective in the future, we suggest greater international cooperation using standardized protocols and methods to monitor and manage European freshwater mussel diversity. Such an approach will not only help conserve this vulnerable group but also, through the protection of these important organisms, will offer wider benefits to freshwater ecosystems.

Distribution patterns and habitat characterization of Simuliidae (Insecta: Diptera) in a low-order sandstone stream (Weidlingbach, Lower Austria)

Abstract A total of 1504 larval and 31 pupal Simuliidae were caught from March 2000 to February 2001 at the Weidlingbach, a fourth order tributary of the Danube near Vienna, Austria, using a modified box sampler (sampling area = 2116 cm 2 ) at 12 sampling stations from source to mouth. From the six species collected, Prosimulium tomosvaryi ( Enderlein ) and two species of the Simulium ornatum -group ( S. trifasciatum Curtis and S. ornatum Meigen ) accounted for 97.5% of the total. Based on head width, instars 1–7 were collected in the S. ornatum -group and instars 2–7 in P. tomosvaryi ; from two of the remaining species [ Simulium ( Nevermannia ) cryophilum ( Rubzov ) and S. ( N. ) vernum Macquart ], only pupae were sampled. The S. ornatum -group was most abundant on coarse substrates (median = 55.9 mm) exposed to high water velocity (median = 55.9 cm/s; range = 9–83 cm/s); the latter was also true for P. tomosvaryi although it favoured smaller sediment grain sizes (median = 32.4 mm). Species richness and population density increased from source to mouth. At sampling sites near the source Simuliidae were completely lacking. In headwaters only P. tomosvaryi was present, whereas the S. ornatum -group and Simulium ( Simulium ) argyreatum Meigen was collected exclusively near the mouth.

Habitat traits, population structure and host specificity of the freshwater pearl mussel Margaritifera margaritifera in the Waldaist River (Upper Austria)

In European streams and rivers, the freshwater pearl mussel (Margaritifera margaritifera L., 1758) faces extinction. This is also true for the Waldaist River, with 20,000 specimens recorded in the early 1990s then Austria’s most important pearl mussel river. Nowadays, there is only a single 320 m stretch with noteworthy mussel densities. During an in-depth survey of this river stretch in 2010, we detected a total of 2,774 specimens. Mussel microhabitats were confined to patches of sand and fine gravel (psammal and akal) at run sections of the river, stabilized by large boulders. Pearl mussels avoided large accumulations of fine sediments. Typically situated at undercut slopes, preferred microhabitats were 0.25–0.50 m deep at baseflow with current velocities (at 40% depth) of 0.2–0.6 m s−1. A comparison of the present stock with data from 1997 revealed a rapid decline in mussel density down to 27%. We also noticed strongly reduced growth and a high mortality of medium age classes. Juvenile mussels were completely lacking. With respect to host specificity in terms of glochidia survival, the brook char Salvelinus fontinalis (Mitchill, 1814), a suitable host in North America, shed glochidia within eight days. In the brown trout Salmo trutta L., 1758, two strains were investigated. Glochidia survival, growth and prevalence were significantly higher in the Danish than in the Austrian hatchery strain.

Basic Aspects for the Ecological Restoration of Urban Water Courses

Abstract Due to the fact that urban water courses provide precious natural and recreational areas within urban surroundings and that they contribute to an increase in quality of life, they have gained more and more importance in recent years. The restoration and planning of urban water bodies pose an enormous challenge, because most of them are in a poor ecological and structural state. This paper deals with the questions and problems concerning the topic and presents basic aspects for the ecological restoration of urban water courses.

The Relevance of Data Interchange for the Effective Protection of Threatened Species by Example of New Records of Endangered Caddisfly Species (Insecta, Trichoptera)

ABSTRACT All over the world, comprehensive data on aquatic communities are collected in the course of applied investigations (e.g. environmental impact assessments for road or railway construction projects, assessments of wastewater treatment plants, hydropower plants, etc.). At the same, little is known about certain endangered or rare species, their distribution or their actual conservation status, as the data collected in applied projects are usually not published. It can be stated that applied investigations would offer valuable information on the distribution of endangered species if there was sufficient data interchange within or data transfer to the scientific community. This thesis is supported by the fact that the authors were able to demonstrate that 72 caddisfly species that are quoted in the Austrian Red List in the course of applied investigations in Austria, but that none of the data have been published so far. The present study provides a list of endangered Trichoptera species that were observed by the authors in the context of routine surveys over the past five years. It is intended thus to provide an example of how data that could be relevant for obtaining a comprehensive picture of certain species are often lost on their way to publication. ZUSAMMENFASSUNG : Die Bedeutung von Datenvernetzung für den erfolgreichen Schutz bedrohter Tierarten am Beispiel neuer Funddaten gefährdeter Köcherfliegenarten (Insecta, Trichoptera). Im Rahmen von angewandten Projekten (beispielsweise Umweltverträglichkeitserklärungen, Vorfluteruntersuchungen o. ä.) werden mitunter umfassende Daten über aquatische Lebensgemeinschaften erhoben. Dennoch gibt es etliche seltene oder bedrohte Arten, über deren Verbreitung oder Gefährdungsgrad aktuell noch zu wenig bekannt ist, weil Daten aus angewandten Projekten üblicherweise nicht publiziert werden. Es kann davon ausgegangen werden, dass angewandte Untersuchungen wertvolle Informationen über die Verbreitung gefährdeter Tierarten liefern könnten, wenn ein ausreichender Datenaustausch stattfände. Diese These wird beispielhaft anhand der Tatsache erörtert, dass die Autoren des vorliegenden Artikels im Rahmen von angewandten Projekten in Österreich bislang 72 Köcherfliegenarten der Roten Liste nachweisen konnten, die entsprechenden Daten aber bisher nicht veröffentlicht wurden. Die hier präsentierte Artenliste soll stellvertretend für eine Vielzahl an Daten stehen, die einen Beitrag zu einem möglichst umfassenden Verständnis gefährdeter Spezies leisten könnten, wenn sie beispielsweise in Form von Publikationen der wissenschaftlichen Gemeinschaft zur Verfügung gestellt würden. REZUMAT : Importanţa interconectării datelor pentru succesul protecţiei unor specii periclitate, exemplificat pe baza de noi date de colectare a unor specii de trichoptere (Insecta, Trichoptera). În cadrul unor proiecte aplicate (de exemplu studii de impact ecologic al şoselelor şi căilor ferate, cercetări privind staţii de epurare a apelor, hidrocentrale, etc.), deseori se prelevează date cuprinzătoare asupra biocenozelor acvatice. Totuşi, există unele specii rare sau periclitate, despre răspândirea cărora sau despre gradul lor de periclitare, în prezent se cunoaşte încă prea puţin, deoarece datele din proiectele aplicate de obicei nu sunt publicate. Putem considera, că cercetările aplicate ar putea oferi informaţii valoroase asupra răspândirii unor specii periclitate, dacă ar exista un schimb satisfăcător de date. Această presupunere se exemplifică prin cercetările autorilor prezentei lucrări, care au reuşit să documenteze în cadrul unor proiecte aplicate din Austria 72 de specii de trichoptere, aparţinând listei roşii din Austria, datele acestea nefiind, însă, publicate până acum. Lista prezentată în lucrarea de faţă este menită să servească drept exemplu pentru o mulţime de alte date, care ar putea contribui la o înţelegere mai amplă a unor specii periclitate, dacă ar fi puse la dispoziţia comunităţii ştiinţifice sub forma unor publicaţii.