Wetland Loss in the Transition to Urbanisation: a Case Study from Western Sydney, Australia

Together with other signatories of the Ramsar Convention, Australia is obliged to seek to halt wetland loss, which may include farm ponds/dams and other constructed wetlands. Since European arrival in Australia, extensive clearing of native ecosystems for agriculture and urbanisation has resulted in a concomitant loss of natural wetlands. However, there is limited information on changes in physical characteristics of wetlands with the transition to agriculture and urbanisation. In North-western Sydney, we investigated changes in wetland surface area, distance to nearest neighbour (connectivity), and shape complexity with transition from natural to agricultural and urban landscapes. There were significant differences amongst land use types for these three waterbody parameters. Wetlands in natural areas were larger and further apart from each other. Half the wetlands in agricultural and urban landscapes had small surface areas, but wetlands in agricultural areas were closer together, so connectivity for biota was potentially greater. Most wetlands in all land use classes were simple or irregular in shape, though urban areas had a higher proportion of irregular wetlands. We predict that on the current trajectory of increasing urbanisation, native biodiversity will continue to decline unless more emphasis is placed on the importance of wetlands - natural and constructed.