Scientist

Faculty of Biology
Aquatic Ecology
Universitätsstrasse 5
D-45141 Essen
Germany

Room S05T03B12

lars.stratmann@bfn.de

Ph.D. thesis topic: Analysis of biological changes in the fish cenosis as a result of restoration measures in the riparian and floodplain area of rivers

Fish play a key ecological role in aquatic ecosystems as consumers at higher trophic levels, contributing to the regulation of nutrient cycling and food webs. Due to their high mobility, fish exhibit diverse habitat requirements on rivers and their floodplains that vary among species and often between different life stages. Nevertheless, considerable knowledge gaps remain regarding the habitat preferences of many European freshwater fish species, particularly non- commercial species and their different life stages. In 2021, 91% of Germany's floodplains were classified as at least significantly degraded. Alterations to floodplain morphology and hydrological dynamics also negatively affect standing water bodies in floodplains. Consequently, the decline of many fish species listed in the German Red List is closely linked to the loss of these habitats.

The aim of this doctoral thesis is to analyze the habitat requirements of European freshwater fish and to investigate changes in fish assemblages in riparian and floodplain habitats following restoration measures. The findings will contribute to a better understanding of the ecological effectiveness of floodplain restoration for fish and support the integration of fish habitat requirements into the planning and evaluation of future restoration projects. This doctoral research is conducted within the BioAu project in cooperation with the German Federal Agency for Nature Conservation (BfN), where the responses of several taxonomic groups to floodplain restoration have already been investigated.