We monitored populations of the Heath Frog Litoria littlejohni in conservation reserves near Nowra on the south coast of New South Wales. Thirteen 250 m transects located along perennial creeks were surveyed at night once a year for 30 minutes each from 2001 to 2006. The sites covered a range of altitudes and vegetation communities and were surveyed between late August and October. The area has a relatively high population density of L. littlejohni, with animals being detected at 12 of the 13 sites. A period of below average rainfall overlapped the census period from 2002 to 2006 and a wild fire in January 2002 burnt 12 of the study sites. The number of frogs detected after the fire declined from 100 to 46. Subsequent surveys found that the population recovered but not to pre-fire densities.
Breeding was evident during each survey by the presence of amplecting frogs, eggs and/or recently hatched tadpoles. Larger tadpoles possibly from the previous year's breeding were detected at some sites. One amplexed pair was retained and laid a total of 194 eggs, which hatched 10-12 days later. The reproductive effort (clutch mass divided by female post partum mass) was 0.34. No L. littlejohni were detected below 130 metres elevation. In 2005 the Plague Minnow Gambusia holbrooki was found at one site and in 2006 the Yabbie Cherax destructorwas found at another site. Predation of eggs and tadpoles from these introduced species may impact on the population of Heath Frog.