Prof. Thomas Hein, seminar

Presenter:

Thomas Hein is a full professor and head of the Institute of Hydrobiology and Aquatic Ecosystem Management at BOKU University (University of Natural Resources and Life Sciences), Vienna, within the Department of Water, Atmosphere and Environment. He leads the BIGER research group, which studies how multiple stressors interact with spatial and long-term change to affect biogeochemical processes and biodiversity in rivers and wetlands, with particular attention to connectivity in aquatic networks and ecosystem resilience. His research spans river, wetland, and floodplain ecology; aquatic biogeochemistry (nutrient and organic matter cycling, greenhouse gas dynamics, carbon sequestration); river restoration and ecohydrology; and socio-ecohydrological systems science. Much of his work centers on the Danube River basin, including coordination of Danube case studies addressing biodiversity and ecosystem management, as well as broader work on connectivity and restoration in riverine landscapes across Europe and beyond.

Seminar description:

Large river ecosystems, such as the Upper Danube, are highly fragmented due to extensive engineering measures for flood protection, hydropower production, and navigation. These modifications have led to the loss of instream habitat diversity, riparian habitats and floodplains, resulting in significant declines in aquatic biodiversity. Despite these challenges, large rivers continue to provide critical ecosystem services and support various human uses. Over the past 25 years, local-scale restoration measures have been implemented in the Upper Danube to improve the ecological conditions, particularly for fish populations and other organisms. This study applies the meta-ecosystem approach to assessing the cumulative effects of these localised restoration efforts across a 150 km-long river network. The meta-ecosystem approach was applied to integrate local habitat conditions and spatial factors by utilising network metrics. By considering the impacts of historical alterations, with a focus on functional longitudinal and lateral habitat connectivity, we evaluated how restoration measures influence ecosystem functions, resilience, biodiversity, and ecosystem services. Results demonstrated how functional connectivity has decreased over the last 200 years, how restoration measures have improved connectivity over the last 25 years, how fish populations are distributed within the current river network, and the migration patterns exhibited by different species. This approach offers a comprehensive framework for better understanding and guiding future restoration strategies in highly modified river systems.