Dagmar Frisch
Professional Experience
Invasion success of crustacean zooplankton: adaptive mechanisms vs. broad physiological tolerance
(collaboration with LJ Weider (University of Oklahoma, USA) and AJ Green (Doñana Biological Station, Sevilla Spain))

Evidence is accumulating that invasive success is influenced by microevolutionary processes such as adaptive capacity rather than by broad physiological tolerance to the environment, enabling colonization of new habitats by invasives that differ greatly from their habitat of origin. We study these contrasting mechanisms using experimental approaches as well as evidence from the field. As model invasive organisms, two crustaceans were chosen which have each invaded new continents across large geographical scales: the water flea Daphnia lumholtzi (Cladocera, Crustacea) native to Africa, Asia and Australia and invasive in North America, and the brine shrimp Artemia franciscana (Branchiopoda, Crustacea) native to the American continent, and invasive in Europe. A detailed spatio-temporal field study of a North American D. lumholtzi population (Lake Texoma, Oklahoma) and genotype by environment (G x E) experiments indicated differential survival of allozyme genotypes related to temperature for Daphnia lumholtzi (Frisch & Weider 2010). In addition, microsatellite genotype diversity appears to follow a seasonal pattern parallel to that of allozyme genotypes (Frisch & Weider, in prep.). The results obtained may explain why the species native to subtropical regions has been able to invade areas outside its normal temperature range, such as in the Laurentian Great Lakes of North America. Our results along a latitudinal gradient in North America and also included populations from the native range suggest that this daphniid was introduced several times to the North American continent and that the source populations are located on more than one continent. Further, the analysis of population genetic structure suggests that the North American populations are structured along a latitudinal gradient, possibly as a result of differing climatic conditions in these regions (Frisch et al. accepted). Complementary studies on the population genetic structure of the invasive brine shrimp Artemia franciscana in a solar saltern near Cadiz, Southern Spain. (Frisch et al. in prep).

Frisch, D., J. Havel, L.J. Weider (2012). The invasion history of the exotic freshwater zooplankter Daphnia lumholtzi (Cladocera, Crustacea) in North America – a genetic analysis. Biological Invasions. Online First DOI: 10.1007/s10530-012-0329-3  PDF

Frisch, D., and Weider, L.J. 2010. Seasonal shifts in genotype frequencies in the invasive cladoceran Daphnia lumholtzi in Lake Texoma, USA. Freshwater Biology 5: 1327 - 1336. 

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Daphnia Lumholtzi

D. lumholtzi distribution in North America
(Frisch et al. 2012. Biol. Invas. Online First)

D. lumholtzi distribution in North America
(Frisch et al. 2012. Biol. Invas. Online First)