Biological invasions in lakes - genetic diversity, timing and local adaptation

• Applicant: Professor Dr. Guntram Weithoff
• Subject Area: Ecology and Biodiversity of Animals and Ecosystems, Organismic Interactions
• Term: from 2014 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 250015247

Due to global mobility and global change many animal and plant species are worldwide dispersed and establish in new regions. These biological invasions negatively affect local and regional communities and may disturb the local diversity. Furthermore, changes in the ecosystems may drastically impact their functions. In aquatic systems, in particular, many invasive species have caused serious ecological and economic consequences such as the zebra mussel, the rainbow trout, the water flea Daphnia lumholtzi and the potentially toxic cyanobacterium (blue-green alga) Cylindrospermopsis raciborskii. Three main factors have been identified determining the invasion success of species: (i) the ecological characteristics of the invading species, (ii) the ecological characteristics of the resident species and (iii) the habitat characteristics. Invasions of higher plants and animals have been often investigated, whereas there is a gap of knowledge in microbial invasions. These will be investigated in this research project by using an ecologically and economically relevant model organism C. raciborskii. The central question addresses the role of the genetic diversity of the invasive species (cf. i) and the genetic diversity of the main resident competitor (cf. ii). According to theoretical considerations, the invasion success increases with an increasing number of genotypes entering a new system at an invasion event. On the other hand it is hypothesized that a high genetic diversity of the main resident competitor hampers an invasion success. In a series of laboratory invasion experiments the invasion success of C. raciborskii into resident phytoplankton communities (with and without its main competitor) will be performed using 10 different genotypes. Furthermore, with an experimentally simulated seasonal plankton development it will be investigated whether a window of opportunity exists during that an invasion is either facilitated or hampered. Additionally, it will be tested whether potential consumers (Brachionus calyciflorus, Rotatoria) have been locally adapted to the new resource in lakes where C. raciborskii has been invaded some decades ago. This project will contribute to fill the gap of knowledge in invasion biology in the field of microbial invasions, genetic diversity and local adaptation.

• DFG Programme: Research Grants