Associate Professor Ian Duggan has just published an important journal article in freshwater ecology: Life on the farm: are zooplankton communities in natural ponds and constructed dams the same?
In urban environments, the construction of new waterbodies, such as dams and retired quarries, are hotspots for invasions relative to natural water bodies. As ponds on farms are relatively little studied, MSc student Kelly Le Quesne examined species of zooplankton - small aquatic animals, with an increasing number of invasive representatives - in constructed and natural ponds on Waikato farms. Kelly aimed to determine whether constructed farm dams are highly invaded relative to natural ponds on farms, and whether these ponds aid in the movement of invaders across landscapes (i.e., whether they provide stepping-stones for spread between towns and cities).
The zooplankton communities found were typical of those found in New Zealand ponds and lakes with high nutrients. The number of non-native species in these ponds, however, was low relative to what is found in urban environments. This indicated that farm ponds are not acting as stepping-stones for movement of zooplankton invaders between urban centres. As such, management to reduce the rate of spread of invasive zooplankton across landscapes needs to focus on other vectors, such as fish stocking and the aquarium trade.