Aquatic Ecology


to the Aquatic Ecology department.

We would like to present the research topics and projects we are working on.

Students can find information about lectures and fieldtrips, also themes for master-, diploma- and Phd-thesis in the teaching section.

You can find the products of our work in the publication section.

If you would like to know who we are and where to find us look a the staff and contact pages.

Talk from Dr. Johannes Radinger, IGB Berlin Modelling Fish in Large European River Systems in Light of Global Change

21.10.2019, 12.15 Uhr, Raum S05T03B94

Climate and land use change have become two dominant drivers of global biodiversity change. Drivers of global change cause species‘ suitabe habitats to move in space and might alter the structure and functioning of entire species communities. However, little is known whether fish species will be able to keep pace with predicted global change-driven habitat shifts, in particular in fragmented river networks. Thus, understanding how global change and connectivity will jointly modify the distribution of riverine species is crucial for conservation biology and environmental management.

Using two different modelling case studies of larger European river systems (Elbe River, Ebro River), I‘ll demonstrate how the future distribution of river fishes will be jointly affected by multiple interacting drivers of global change.
In the first case study – the Elbe River – we coupled species distribution models of 17 fish species with species-specific models of their dispersal. This allowed (i) to quantify the extent and direction of predicted habitat shifts under coupled climate and land use change scenarios, (ii) to assess the dispersal abilities of fishes to track predicted habitat shifts while explicitly considering movement barriers, (iii) to identify species traits that are particularily affected by global change.

In the second case study – the Ebro River, located within the Mediterranean region particularily threatened by global change – we addressed the interaction of climate change, connectivity and invasive alien species, that pose a further dominant threat to biodiversity. Specifically, we applied joint species distribution models to quantify the co‐occurrence of native versus alien fish species that can be attributed to shared environmental responses or potentially to biotic interactions. Furthermore, we modelled the future distributions of the habitats of native and alien fishes. By assessing effects of connectivity on the accessibility of future suitable habitats we identify most conflict-prone river reaches, i.e. where barriers pose a particular trade-off between isolating and negatively impacting native species vs. potentially reducing the invasion risk of alien species.
Overall, these studies emphasize the importance of the complex effects that climate change, riverine connectivity and other drivers (such as invasive species) are expected to impose on river communities and the urgent need to adapt management strategies accordingly.

Website IGB

MARS project: international study about safeguarding the banks and margins of streams and rivers When to trust your bank manager: riparian zones to protect and restore rivers

Safeguarding the banks and margins of streams and rivers has a key role in ensuring aspects of river health.

That’s the major conclusion from a new international study just published in Water Research.

Protecting, planting and restoring native plants and their habitats alongside rivers provides food for aquatic organisms and prevents high temperatures in the fight against global warming.  Bankside ‘riparian zones’ can also prevent some of the pressures on rivers that arise from activities in their wider catchment – such as farming – but not always.

Rivers provide critical human resources, such as clean water, food and recreation, but are threatened increasingly by pollution, physical modification and over-exploitation.  While international efforts, such as the EU Water Framework Directive, aim at evaluating and restoring river health to protect biodiversity and people they are not always effective in reversing damage.  A key need has been to evaluate why, and to find the options that work best under different circumstances.  

The international team of researchers addressed this need during the EU MARS project by reviewing available scientific literature, asking which vegetation types were linked to successful restoration.  They also evaluated how riparian management reduced impacts from nutrients, sediments and high temperatures, and whether biological quality could be improved.
While riparian revegetation had limited effects on nutrients, sediments and biological quality, woody riparian vegetation consistently increased leaf-litter inputs to rivers (a key food source), also improving habitat quality in the form of woody debris and reduced water temperature. Positive effects were greatest where riparian management took place in the upper parts of rivers – where proportionately more river flow is affected by the riparian zone.

Leader of the study, Dr Christian Feld said “Land management such as farming or forestry are essential for the World  - but can damage rivers downstream. We therefore need ways to reduce the unwanted effects, and management of the riparian zone has long been proposed as a cost-effective and local solution.  Our evidence shows that riparian restoration can be effective in offsetting some problems, but not all.  Bigger-scale problems such as pollution from agricultural chemicals or sediments will need bigger-scale solutions applied through improving the management of whole river catchments".

Professor Steve Ormerod said “This whole issue is one that needs more holistic, ecosystem management.  Fresh water is a crucial human resource that needs care, maintenance and sometimes very expensive treatment before it can be supplied to people.   Freshwater ecosystems are also losing biological diversity at an alarming rate globally because they are not well protected.   We need to step up efforts to balance productive land use against these downstream costs - and our work shows that this needs a blend of local riparian solutions as well as improved large-scale thinking.”

The work was funded by the EU MARS project under project No.: 603378.

Contact: Dr. Christian K. Feld

Link to article


New study Massiv loss in insect biomass

Global declines in insects have sparked wide interest among scientists, politicians, and the general public. Loss of insect diversity and abundance is expected to provoke cascading effects on food webs and to jeopardize ecosystem services. The analysis estimates a seasonal decline of 76%, and mid-summer decline of 82% in flying insect biomass over the 27 years of study.

Thomas Hörren, student at the UDE Aquatic Ecology department, is co-autor of the paper.

link to paper

Study of the department of Aquatic Ecology within the EU project BioFresh Natural and anthropogenic factors influence aquatic biodiversity in concert

This is the conclusion of a study of the department of Aquatic Ecology within the EU project BioFresh. The study aimed at quantifying the impact of anthropogenic land uses on the diversity of eleven aquatic organism groups (e.g. fish, amphibia, insects, plants).
An international team of researchers  investigated biodiversity data from rivers, lakes, floodplains and wetlands, ponds and groundwater. Despite the heterogeneous character of the ecosystems considered, the results are consistent: natural factors such as temperature, precipitation and altitude act in concert with anthropogenic factors and together determine biodiversity. Their joint influence cannot be fully disentangled, which in particular holds trou for large-sclae studies, for example at the continental scale. This may seem trivial at first glance, but bears fundamental implications for future studies on aquatic biodiversity. The study has been published in the journal Ecological Indicators.

Vienna/Berlin/Essen/Brussels, May 6, 2015 Four leading European research institutes launch unique Freshwater Information Platform

Four European research institutes have launched an online platform to make information from a large set of freshwater ecosystem research activities accessible to all. The Freshwater Information Platform offers a forum for information exchange and open-access publishing of maps and data, and aims to stimulate cutting-edge research and collaborations in the field. The Platform provides a unique and comprehensive knowledge base for sustainable and evidence-based management of our threatened freshwater ecosystems and the resources they provide.

Pressures such as water pollution, intense land-use and climate change are increasingly threatening the health and diversity of European freshwater ecosystems. Over recent years, many European Union funded research projects have investigated the causes of these pressures and their effects on rivers, lakes and wetlands, and developed appropriate rehabilitation strategies. However, access to and use of the data generated by these projects is often difficult for water managers, policy makers, scientific communities and the general public. This is, because scientists have not yet fully adopted systematic data publishing practices and data embedded in the huge number of scientific papers and research project websites are challenging to extract.

In order to make this detailed and wide-ranging knowledge of freshwater ecosystems accessible to all, four European research institutes in Austria, Belgium and Germany have joined forces to launch the Freshwater Information Platform, an interactive website integrating results and original data stemming from finished, ongoing, and future freshwater research projects.
The platform contains several complementary sections, either providing access to original data or summarising research results in an easily digestible way. All sections are composed as ‘living documents’ that will be continuously improved and updated.

Contributing institutions and contacts:
University of Natural Resources and Life Sciences (Vienna, Austria), BOKU
Astrid Schmidt-Kloiber (, +43 1 47654 5225

University of Duisburg-Essen, Aquatic Ecology (Germany), UDE

Daniel Hering (, +49 201 183 3084 & Jörg Strackbein

Leibniz-Institute of Freshwater Ecology and Inland Fisheries (Berlin, Germany), IGB
Klement Tockner (, +49 30 64181 601 & Vanessa Bremerich

Royal Belgian Institute of Natural Sciences (Brussels, Belgium), RBINS

Koen Martens & Aaike De Wever (, +32 2 627 43 90

Read full press release

More on the Freshwater Information Platform

Successful blog 100.000 readers and more

Within the EU funded project BioFresh, in which the Aquatic Ecology was part of the consortium, a blog was started with a wide range of topics all around water, freshwater and aquatic life.

2011 it was listed by Nature as one of the 'recommended conservation blogs'.

With start of the MARS project in February 2014 the blog is now continued by the working group.

In April 2014 the blog has broken the barrier of 100.000 readers (in total since 2010). The average number of readers is between 2000-3000 per month, in May 2014 more then 7300 people were reading our blog posts.

Want to further strengthen their cooperation: Dr. Dana Milstein (Israel Nature and Park Authority), Alon Zask (Israel Ministry of Environmental Protection), Prof. Tamar Dayan, Dr. Yaron Hershkovitz, Prof. Avital Gasith (Tel Aviv University), Dr. Christian Feld (back) und Dr. Armin Lorenz (University of Duisburg-Essen) (from left to right). (Photo: Christian Feld)

UDE experts on mission in Israel Wanted: Bioindicators for Israeli waters

Invited by the Israeli Ministry of Environment Protection, Dr. Christian Feld und Dr. Armin Lorenz attended an expert mission to discuss the development and establishment of a bioindication system for rivers in Israel. The UDE experts met with colleagues from Tel Aviv University, the Israeli Nature and Park Authority and the Water Authority. They were accompanied by Yaron Hershkovitz from Tel Aviv University, who’s currently finishing his two-year guest stay at the Department of Aquatic Ecology, University of Duisburg-Essen.

During a one-day symposium, the UDE experts presented the scientific steps towards the development of a national bioindication and biomonitoring system for rivers in Israel and further presented ways to implement the outcome practically. Their expertise is based on more than a decade of research in course of the European Water Framework Directive, one of the main research fields of their Department at the University of Duisburg-Essen.

Israel’s waters - naturally rich and diverse - have undergone significant modification during the past decades, a process that is largely driven by the increase of human land and water uses. Constantly growing industrial and municipal water demands, but in particular the intensive row-crop agriculture and the increasing recreational water uses impose serious threats on Israel’s waters and their ecological integrity. Food production is inevitably linked to irrigation in many regions of the country. Consecutive dry winters in the past years and future climate change are likely to amplify the water-related problems.

The Israeli hosts impressively presented this during the initial one-day symposium. Together with the German Experts, they discussed the options to detect and monitor the far-reaching ecological implications of the manifold water uses. A first goal will be the nation-wide inventory of the aquatic diversity, which is closely linked to the establishment of the National Taxonomic Institute at the University of Tel Aviv. One of the institute’s tasks will be to coordinate the sampling, identification and ecological attribution of the aquatic biodiversity, a prerequisite for the development of a bioindication system. Therefore, it is planned to further extend the cooperation with the University of Duisburg-Essen.

Eventually, Dr. Feld und Dr. Lorenz were invited to several field trips, which lead the ecologists to the sources of the upper Jordan River, further along the Jordan and down to the Dead Sea oasis. Together with a final tour along the course of the Yarkon River, the ‘green lung’ of the Tel Aviv metropolitan area, the field trips helped understand the manifold water uses and its implications for the aquatic environment and human welfare.

The mission of the two UDE experts was funded by the European Commission, DG Enlargement, through the „Technical Assistance Information Exchange Instrument (TAIEX, ETT55742)“.

New study Degraded, species-rich, but biologically less diverse

This title briefly summarizes the study of Dr. Christian K. Feld, Department of Aquatic Ecology, University of Duisburg Essen, and his co-authors that has recently been published in Freshwater Biology online early. Therein, the authors investigated the response of several benthic macroinvertebrate diversity metrics to hydrological and morphological degradation of Central European lowland rivers.

The authors found only a very weak response of species richness (and several other metrics tested) to degradation. However, the results show an almost complete turnover of species from natural to degraded rivers and thus confirm the adverse effects of degradation on biodiversity. This effect usually remains undetected if classical biodiversity indicators (e.g. species richness, Shannon-Wiener diversity) are being used. Dr. Feld and co-authors thus conclude that additional indicators should be applied in ecosystem assessment that are capable of detecting such structural and functional changes toward degradation of riverine communities. The study is available at

From the departmentNew publications

Le, T.T.Y., García, M.R., Grabner, D., Nachev, M., Balsa-Canto, E., Hendriks, A.J., Zimmermann, S., Sures, B. (2020) Mechanistic simulation of bioconcentration kinetics of waterborne Cd, Ag, Pd, and Pt in the zebra mussel Dreissena polymorpha. Chemosphere, 242, 124967. link to article

Erasmus, J.H., Malherbe, W., Zimmermann, S., Lorenz, A.W., Nachev, M., Wepener, V., Sures, B., Smit, N.J. (2020) Metal accumulation in riverine macroinvertebrates from a platinum mining region. Science of The Total Environment, 703, 134738. link to article

Riegels, N., Lynggaard-Jensen, A., Krogsgaard Jensen, J., Gerner, N.V., Anzaldua, G., Mark, O., Butts, M., Birk, S. (2019) Making the ecosystem services approach operational: A case study application to the Aarhus River, Denmark. Science of the Total Environment, in print link to article

Iversen, L.L., Winkel, A., Hinke, A.B., Alahuhta, J., Birk, S., Brodersen, P., Chambers, P.A., Ecke, F., Feldmann, T., Gebler, D., Heino, J., Jespersen, T.S., Moe, S.J., Riis, T., Sass, L., Vestergaard, O., Maberly, S.C., Pedersen, O. (2019) Catchment properties and the photosynthetic trait composition of freshwater plant communities. Science, 366, 878?881. link to article

Borgwardt, F., Leitner, P., Graf, W., Birk, S. (2019) Ex uno plures ? defining different types of very large rivers in Europe to foster solid aquatic bio-assessment. Ecological Indicators, 107, 105599. link to article