The creeks and wetlands of the Homebush Bay area have been contaminated by leachate from past waste disposal practices and flows modified by the use of concrete channels for creeks. A bund wall along the Parramatta River also reduced tidal flushing vital to the wetlands. Monitoring studies found that the abundance and diversity of fauna and flora in the creeks and wetlands were patchy (Berents 1996). The freshwater ponds and reedbeds were found to support many bird species, including dusky moorhens and royal spoonbills. They also provide habitat for some migratory bird species, which Australia has responsibility for protecting under bilateral migratory bird protection agreements (Straw 1996b). However, the wetlands were poor in fish species diversity compared with the bay and the creeks (Smith et al. 1996).