The grey-headed flying fox and the green-and-golden bell frog (pictured) are under threat in Chipping Norton, Hammondville and Casula while the regent honeyeater, swift parrot and koala are at risk throughout the areas.

For Landcare Week (September 1 to 7), Landcare Australia asked people to volunteer to be part of urban Landcare groups after a city-wide survey found that one in 10 of Sydney's wildlife species is under threat.

Landcare Australia chief executive officer Brian Scarsbrick said the survey results were alarming.

``This study is a call to arms for anyone interested in preserving our wildlife to volunteer for their local urban landcare group and help protect and restore the natural habitat of our threatened indigenous wildlife,'' he said.

``We need to act now if we're going to save the 53 species under threat.''

Threats include habitat loss, water quality, bushfires, weeds, limited habitat links, watercraft, feral predators and military exercises.

Join your nearest Landcare group through www.landcareonline.com/directory.