Wissenschaftlicher Mitarbeiter

Fakultät für Biologie
Aquatische Ökologie
Universitätsstr. 5
D-45141 Essen

Raum S05T03B08
 

damian.biehs@uni-due.de

Biotic and Abiotic Drivers of Macroinvertebrate Dispersal

The dispersal ability of aquatic macroinvertebrates - how, why, and how far they move - is crucial for understanding species recolonization following river restoration. In my PhD project, I investigate the biotic and abiotic factors shaping dispersal patterns in stream invertebrates. A particular focus lies on in-stream and overland dispersal barriers as well as species-specific and individual dispersal capabilities.

My research is conducted in three catchments with contrasting land-use intensities: the heavily urbanized Emscher/Boye system, the semi-rural Rotbach, and the near-natural Kinzig catchment. Within these systems, I focus on twelve model species, including the hololimnic amphipod Gammarus pulex and several merolimnic mayfly, stonefly, and caddisfly species.

To track individual dispersal distances in the field, I apply ¹⁵N stable isotopes, which enable the labelling and tracking of aquatic stages and emerging adults over several hundred meters. Malaise traps are used to capture these adults as well as to quantify emigration rates from local populations.

To complement these short-term field data, I analyze long-term gene flow using CO1 barcoding and ddRAD sequencing. These data will provide insight into interpopulation connectivity over longer timescales and allow assessment of how in-stream and overland barriers affect dispersal in hololimnic and merolimnic taxa.

Using the resulting data on dispersal rates and distances, I aim to construct leptokurtic dispersal kernels, mathematical functions that describe the proportion of individuals dispersing relative to distance from the source. These kernels are then integrated into species dispersal models, which will combine species-specific traits with empirically measured individual dispersal ranges.

The ultimate goal of this research is to improve predictions of when and how aquatic species disperse. These insights will support river managers in designing more effective restoration strategies and enhancing the ecological resilience of freshwater ecosystems.