The ecology of mosquito populations in relation to weather conditions, emergent plants and predation in an urban wetland of Canberra was studied. Anopheles annulipes, Aedes notoscriptus, Aedes australicus, Aedes alboannulata, Culex annulirostris and Culex quinquefasciatus were found. Temperature was a major climatic factor in determining the abundance of mosquito populations in the wetland. First collections and subsequent development of mosquitoes in Ginninderra wetland are likely to depend on local weather conditions each year. The wetland proper was not a suitable habitat for mosquito breeding. Tall emergent vegetation may have obstructed oviposition and predation was also important in limiting colonization by mosquitoes. Instead, isolated temporary waterbodies which were free of predators, such as ground depressions, tyre tracks, domestic waste containers, were the most important habitats for mosquitoes adjacent to the Ginninderra wetland. Field experiments found that predation of mosquito larvae by mosquitofish Gambusia qffinis and notonectids Anisops was more efficient in sunlight than shade and this was affected by the height of emergent plants.

Giralang Pond was a water body, with little emergent or submerged vegetation, designed to trap fine sediment and buffer input of rising water to Ginninderra Wetland downstream. Ginninderra Wetland was designed to retain and use sediment nutrients and other potential hazardous materials in urban run-off. Water in the Wetland was more turbid and had lower magnesium concentration, redox potentials and dissolved oxygen concentration than did Giralang Pond. Water temperature was a minimum of 4 °C in the winter and reached a summer maximum of 30 °C Giralang Pond had more organisms but fewer taxa than Ginninderra Wetland. The greatest abundance in the pond resulted principally from high numbers of two numerically dominant species Calamoecia sp. and Micronecta sp.. More organisms were found in vegetated habitats of Ginninderra Wetland than open water habitats. The number of invertebrates and the number of taxa found in Typha domingensis did not differ significantly from similar estimates for Schoenplectus validus, Gambusia qffinis was the dominant predator in both water bodies. On one occasion, G. qffinis reached population densities of 35 individuals per m-2 . G. qffinis was five times more abundant in Gininnderra Wetland than in Giralang Pond and also showed a preference for vegetated areas. G. qffinis over-grazed it's prey on several occasions. G. qffinis, invertebrate predators and prey followed a pattern of a community in a stable predator-prey cycle. Prey in early spring increased population numbers and then decreased when G. qffinis and other predators increased their numbers. The pattern was further strengthened by occurring in both areas of open water and vegetated habitat types.