Since the first of September 2001, I joined the Leibniz-Institut für Gewasserökologie und Binnenfischerei (I.G.B.) where I managed several projects as Post-Doc and then as guest scientist. Since 2005, I developed at the IGB a sub-working group which focuses on understanding and modelling the impact of certain hydraulic disturbances (mainly ship- and wind-induced) on littoral invertebrates. In this framework, collaborations are developed with the University of Konstanz (Germany - Stefan Stoll), the Nanjing Institute of Geography and Limnology in Beijing (China - Dr. Gong Zhijun) as well as internally (Dr. S. Sukhodolov, Dr. C. Wolter).

Impact of ship-induced waves on littoral zoobenthos. (Guest Scientist)

Project description - The impacts of ship-induced waves on littoral zoobenthos are often cited despite they are hardly investigated. Own laboratory experiments showed well reproducible, short-term drift effects on several invertebrate species. In the proposed project, results of these laboratory experiments are verified in field conditions with combined hydrodynamic and ecological measurements. These results are complemented by the investigation of long-term impacts on the invertebrate communities and their habitat in laboratory and under field conditions. Focus is put on shift in species composition and community structure including favour to invasive species and reduction of invertebrate productivity. Additionally, in further laboratory experiments the pre-adaptations of certain invertebrate species, especially of neozoons, to temporally occurring high shear stresses are investigated. The results of both approaches are the basis for a combined hydrodynamic-ecological modelling of the short-term impacts. These results are complemented by investigation of fairly long-term impacts, like shift in the species composition and a reduced productivity, in the laboratory and under field conditions. The aim of the study is to quantify the impacts of ship-induced waves on the littoral zoobenthos and hence to develop an ecologically optimised shore line embodiment of inland waterways.

Working group - Dr. M. Pusch

Financial support - German Federal Foundation for the Environment (2007-2010).

Development of a fish based model using fish functional attributs for the ecological assessment of the German lowland lakes. (Guest Scientist)

Project description - In order to further develop the fish based model developed to assess the ecological quality of  the German lowland lakes (see below), this project aimed to define a lake typology based on functional characteristics (species traits) of  fish assemblages. Three lake functional types were described which showed a strong correspondence with lake morphometry and productivity,  thus indicating that environmental conditions of lakes imposed constraints which favoured only certain functional attributes of fish. Accordingly, it results in a mechanistic understanding of the processes structuring lake fish assemblages, and supports the environmental filter concept. It is suggested that a functional typology may simplify bioassessment systems which are currently based on long lists of potentially sensitive indicators.and observe changes in fish functional attributs along environmental gradients.

Working group - Dr. T. Mehner

Financial support - German Federal Ministry of Education and Research (2006).

Development of a fish based model for the ecological assessment of the German lowland lakes. (Guest Scientist)

Project description - This project, similarly related to the European Water Framework Directive concerns than the one described above, was mainly carried out by Dr. Markus Diekmann. I came to work on this project to analyse a part the collected data. This analysis identified two distinct depth-related lake types exhibiting specific fish assemblages and demonstrated that the assessment of eutrophication in lakes by their fish fauna is generally possible, if lakes are initially separated according to a depth-related morphotype before the assessment.

Working group - Dr. T. Mehner

Financial support - German Federal Ministry of Education and Research (2005).

Development of a macrozoobenthos based model for typology and ecological quality assessment of the Brandeburg's lakes. (Guest Scientist)

Project description - The European Water Framework Directive (2000/60/EC) requires from the state members an assessment of the ecological quality of their lakes. The existing assessment systems are based on biological, hydro-morphological, physical and chemical criteria, however they have been mainly developed for flowing waters. At the present time, no system exists in Germany to assess the ecological quality of the lakes.

This project aimed to work out the bases of such a system in order to classify or restore the lakes. Focus was made, according to the WRRL wishes, on the use of macro-invertebrate assemblages associated to littoral structures. Mean depth and residence time were found as key factors in structuring the benthic macroinvertebrate assemblages in the sublittoral zone. This study also demonstrated that eulittoral faunal assemblages, mainly influenced by the structure of the habitat, are no suitable indicators to assess eutrophication in lakes. In contrast, the sublittoral faunal composition fully respond to trophic gradients.

Working group - Prof. N. Walz

Financial support - Environmental Agency, Federal State of Brandenburg  (2001-2002)

Management of fluvial waterways : Ecological effects of groyne construction types. (Post-Doc)

Project description - This project aimed at the comparison of the ecological effects of a standard and an alternative way to provide shore stability in a navigable large river, the Elbe River (Germany). Ecological effects of three groyne types: conventional groynes, destroyed groynes and longitudinal groynes were assessed in terms of sediment types and stability, faunal diversity, specificity and productivity, with special reference to non-indigenous species, in order to define recommendations for a shore protection method with least adverse effect on invertebrate fauna. The study shown that the destroyed and longitudinal groynes fields exhibit a higher sediment dynamics. There, faunal diversity and productivity, supported by contrasted fluvial morphostructures, were higher than in the conventional groyne fields. Also, the river shore with destroyed groynes tended to harbour less neozoa than other shore protection types. From that, it can be expected that invertebrate biodiversity and biomass in the River Elbe could be significantly increased with a shore protection type allowing small secondary flow paths near the shore, which would hardly affect commercial navigation on the river.

Working group - Dr. M. Pusch

Financial support - Marie Curie Fellowship (European Union, 2002-2004).