Daphnia lumholtzi, an exotic zooplankton, has invaded freshwater systems throughout the southern and midwestern United States. A study done by Dzialowski et al 2000 conducted regional surveys of eastern Kansas reservoirs to document the range of expansion of D. lumholtzi. It was found in five out of 35 reservoirs sampled in 1994, and 11 out of the 35 reservoirs when re-sampled in 1997. In addition, 40 small ponds inaccessible to recreational boats were sampled, where no D. lumholtzi was found. This suggests that non-human dispersal mechanisms play an insignificant role in the spread of the species.
This study suggests that further experimentation is needed to determine if the absence of D. lumholtzi from these ponds is due to insufficient dispersal mechanisms or the species’ inability to colonize in this environment.
Dzialowski A.R., O’Brien W.J., and Swaffar S.M. 2000. Range expansion and potential dispersal mechanisms of the exotic cladoceran Daphnia lumholtzi. Journal of Plankton Research. Volume 22. Issue 12: 2205-2223.