Analysis of changes in insect communities in water bodies in Hamburg

The scientific collections of the Museum of nature - Zoology look back on a tradition of over 120 years and can make a weighty contribution to the elucidation of earlier settlement patterns and associated structural conditions in Hamburg's waters. It was primarily deserving Hamburg citizens such as the elementary school teacher Dr. Georg Ulmer (1877-1963) who, with their unparalleled commitment, established the scientific collections as archives of Hamburg's historical settlement. For example, LIB scientists are currently reconstructing historical settlement patterns of prominent Hamburg water bodies such as the Elbe (Süderelbe), Isebek, Tarpenbek and the Eppendorfer Moor. Various invertebrate groups such as insects (including caddisflies and dragonflies) and freshwater molluscs are used as indicator organisms. Furthermore, an intensive evaluation of historical documents from the scientific archives of LIB is carried out.

As a city on the water, Hamburg owes its economic and cultural success to its numerous watercourses more than almost any other German metropolis. In addition to their outstanding economic importance, watercourses provide recreational spaces for the urban population and serve as the basis of life for numerous animal and plant species. In a research project, zoologists are using historical specimens to examine how human intervention in the unique material balance of selected city waters and the interwoven biocoenosis has affected them over the last 120 years.

Every water ecosystem is characterised by a specific biocoenosis perfectly adapted to the respective ecological conditions. The plant and animal species living there react extremely sensitively to changes in habitat factors such as nutrient input, wastewater and pesticide contamination, bank development, regulation of the flow regime, etc. Thus, especially in urban areas, watercourses have been subjected to massive anthropogenic changes since the beginning of the 20th century. Today, however, there is a growing awareness of the integrative function of intact watercourses as a retreat and recreation area for the urban population. As a result, individual watercourses that have been heavily anthropogenically deformed are being renatured. However, these measures have repeatedly shown that a reconstruction of the structural and especially the biocenotic initial state is often not possible or only possible to a limited extent due to a lack of data, which makes targeted renaturation measures and an evaluation of success significantly more difficult. LIB´s extensive regional caddisfly collections are an excellent scientific resource to compensate for these deficits.

For the Eppendorfer Moor, an outstanding position as a unique and species-rich inner-city lowland moor could thus already be highlighted. The project thus makes a fundamental contribution to the preservation and enhancement of intact, life-friendly water bodies in the heart of Hamburg.

Contact person: Martin Kubiak