Since European Settlement the native plant life have been considerably affected , with the native manna gum and blue gum woodlands being largely cleared for agricultural uses . The large amount of non @-@ native vegetation in the gully is predominantly the result of the early agriculture , although some species was introduced by accident . Introduced species include olive trees , hawthorn , fennel and blackberry . With the reduction of native flora , exotic fauna have flourished around the Waterfall Gully region . These include rabbits , blackbirds and starlings . However , not all of the native wildlife have been lost — bats ( in particular , Gould 's wattled bat ) , can be found in the area , as can superb fairy @-@ wrens and Adelaide rosellas , and a large number of unique Australian animals such as kangaroos , koalas and possums can be spotted on some of the walking trails .