Australia Post is highlighting the diversity and importance of native frogs to the environment in its latest stamp issue that features five frog species, three of which are classified as at-risk.

Australia Post Philatelic Manager Michael Zsolt said Australia is home to about 200 of the world's 6,000 frog species.

"This stamp issue indicates some of the diversity of our frog species, brought to life through eye-catching photorealistic illustrations," Mr Zsolt said.

"Frogs occupy an important niche in the food web, being both predators and prey, and they are one of nature's barometers for environmental health, given their sensitivity to environmental conditions. So declining numbers do not bode well, and we are pleased to help raise awareness of the frogs' plight, featuring three at-risk species in the stamps."

Frog numbers have declined rapidly in Australia since the 1980s, a pattern that is reflected globally. The reasons for this are not fully understood, but include factors such as the Chytridiomycosis fungus, which impedes a frog's ability to breathe through its skin, and the effects of climate change and land clearing.

Between 1979 and 1997, four native species of frogs have become extinct – the Northern Gastric and Southern Gastric Brooding Frogs, the Sharp-snouted Day Frog and the Mount Glorious Day Frog – while many others have since become critically endangered or endangered.

Western Australia–based artist Owen Bell illustrated the frogs featured on the stamp issue. The species represented on the four $1 base rate stamps are:

  • Baw Baw Frog (Philoria frosti): Listed "critically endangered" on the International Union of Conservation of Nature's (IUCN) Red List and endangered in the Environment Protection and Biodiversity Conservation (EPBC) Act, the Baw Baw frog is found in an area of only 80 square kilometres on the Mt Baw Baw Plateau in Victoria.
  • Australian Lace-lid (Litoria dayi): Listed "endangered" in the EPBC ACT and on the IUCN Red List, this frog is endemic to the Wet Tropics Bioregion of northern Queensland where it is associated with rainforest areas with fast-flowing creeks.
  • Armoured Mist Frog (Litoria lorica): Listed "critically endangered" in the EPBC Act and on the IUCN Red List, this small tree frog is one of Australia's most at-risk amphibians. It is restricted to an area of about four square kilometres in north-eastern Queensland.
  • Tasmanian Tree Frog (Litoria burrowsae): As its name suggests, this frog is endemic to Tasmania and is also the state's only known tree frog. It is restricted to the west side of Tasmania, where its preferred habitat is buttongrass moorland, sedgeland and forest.

A fifth species, the Dainty Tree Frog (Litoria gracilenta), is featured on a minisheet. This frog inhabits areas along the coast from Cape York to Sydney, preferring damp forest and woodland settings, as well as areas of low vegetation such as gardens.

The associated products available are a stamp pack, first day cover, maxicard set and 2 x medallion covers. The stamp issue is available from 4 July 2018 at participating Post Offices, via mail order on 1800 331 794 and online at auspost.com.au/stamps while stocks last.