Nov
29
Filed Under (Uncategorized) by Brianca King on 29-11-2010

The issue of invasive species has been gaining importance as invasions have become more common throughout ecosystems.  Since the success of an invasion can be affected by the suitability of abiotic factors, Kristen A. Work and Moshe Gophen conducted a study at the University of Oklahoma that was featured in Freshwater Biology to determine whether variations in food availability, turbidity, temperature, and conductivity affected the survival, reproductive, and molting rates of Daphnia lumholtzi.

D. lumholtzi was chosen as the test subject because it is a cladoceran zooplankton with an increased ability to colonize North America due to the similarity between the water temperature of its native habitat and the new habitat, and due to its long head and tail spines which make it undesirable to many predators.  The results of the experiment showed that reproductive rates increased with food concentration and temperature, was not affected by conductivity, and was best at no turbidity. Molting rates increased with temperature, was strongly affected by turbidity, and was not significantly affected by food supply or conductivity. Survival rates were best at moderate conductivity, declined with temperature, and was not significantly affected by food supply.  However, it is important to note that D. lumholtzi was able to survive and reproduce in all of the conditions tested.  Overall, this study emphasized that the sustainability of abiotic factors can be used to predict whether cladoceran zooplankton species are likely to invade a habitat or not.