Aquatic and terrestrial systems can be very similar regarding the fundamental characteristics of function and structure. However, ecologists tend to focus on either the dry or the aquatic realm but these systems are rarely investigated under the premise of being tightly linked and being influenced by similar processes. Integrating the perspective of cross-boundary effects into the conceptional design of ecological studies could help to evaluate the consequences of biodiversity loss on the landscape level.

Together with students, colleagues and collaborators, I focus on trophic interactions and strive to understand the effects that structure food webs within and among ecosystems. We combine stable isotope and morphological techniques, fatty acid analyses and behavioral studies that include field surveys, manipulations in the field, mesocosm experiments, as well as laboratory experiments.

Due to massive anthropogenic use and engineering, the River Rhine became a hotspot for species invasion. Gobies for example, invaded the Rhine in different waves and also from different directions. Since 2010, we conduct standardized angling campaigns to monitor goby abundances in the Lower Rhine. Currently, we are focusing on the latest invasion in the River Rhine, the Caucasian Dwarf Goby Knipowitschia caucasica that was reported first in 2019. We are studying the mating tactics and population dynamics of this fish.

The lowlands of the Lower Rhine have huge deposits of sand and gravel that have been mined in this area for the last 100 years. The resulting gravel pit lakes are on of the most common type of water bodies in this area. In a project funded by the Deutsche Bundesstiftung Umwelt, the Ecological Research Station is investigating population dynamics of aquatic organisms in two gravel pit lakes that have the peculiarity of being fish-free, or were fish-free until recently. The natural invasion of subleak Leucaspius delineatus in 2019 allows us to investigate changes in species communities due to top-down effects under natural conditions.

The burbot Lota lota is a freshwater fish that has been classified as threatened with extinction in North Rhine-Westphalia. The Stiftung Wasserlauf NRW is carrying out a conservation project that was funded by the Federal Agency for Nature Conservation. The Ecological Research Station provides scientific support for this project, particularly regarding the ecology of this fish species.