Research interests

1. population differentiation and speciation
2. clonal reproduction
3. adaptation and interaction
4. conservation

I use an integrative research approach that includes molecular techniques in combination with ecological investigations and behavioral experiments and different animal model systems:

The Amazon molly, Poecilia formosa is my main model for studying the evolution and maintenance of clonal reproduction. It is an all-female hybrid species and reproduces gynogenetically, i. e., it produces unreduced diploid eggs but needs sperm from a closely related sexual species to trigger the onset of embryonic development. Usually, the male genetic material is excluded from the oocyte and does not contribute to the offspring (clonal reproduction). Clonal vertebrates are generally thought to be evolutionarily young, slow to evolve and due to the lack of recombination very vulnerable to accumulation of mutations. There is, however, evidence that despite its clonal reproduction P. formosa is quite successful ecologically and also much older than expected. The questions I am interested in the system are therefore, how can unisexuals survive in rapidly changing environments and successfully compete with closely related sexual species.

In stream ecosystems fish are highly mobile top predators that significantly shape food-web interactions. They are also highly affected by water quality and immediately respond to water quality changes. The project investigates stress response patterns in fish focusing on sculpins (Cottus). We are working on a detailed analysis of dispersal and re-colonisation patterns as well as an analysis of adaptation to stressors and stressor combinations. In addition, the influence of Cottus on prey invertebrates and the food web in general will be investigated. To answer these questions we combine field work with population genetic analyses and advanced NGS techniques and complex data analyses including modelling.

This project is a co-operation with the Geology department and aims to investigates how tectonic uplift has influenced drainage evolution in northern Chile. Surface displacement due to faulting can reroute and force reorganization of stream networks. This process has been shown to be prevalent throughout northern Chile, where relatively minor amounts of fault slip can result in channel avulsion. In addition to established and novel geochronological techniques we use amphipod genotypic diversity and molecular clock estimates to identify and date historic routes and connections between different drainage systems.

Because Daphnia can switch between clonal and sexual reproduction they are interesting models to test the advantages and disadvantages of clonal reproduction and the adaptability of clonal populations. We investigate factors (mainly predation and CO2) that influence the genotypic Variability in natural and artificial Daphnia populations.

Molecular methods are recently also used more and more in conservation contexts. In co-operation with consultants for landscape planning committees we collect molecular evidence for the presence/absence of endangered/protected species (e.g. wild cats). We investigate the origin and genotypic diversity of invading fish species and give advice to re-introduction projects. In addition to DNA evidence from tissue samples, hair, feathers or dung we also use eDNA to e.g. test for the presence of crested newt in local ponds.

Current projects are the genotypic characterization of the invasive round goby and identifying invasion routes of nutrias.