Threats to frogs

Eight frog species have become extinct in the last 25 years, and several more are likely to become extinct in the near future.

Threats to frogs include the following.

Pollution

Frogs generally spend part of their lifecycle in water, and their moist skins are especially sensitive to pollution. Ways of reducing the impact of pollution on frogs include:

• preventing chemicals such as petrol, insecticides, detergents and fertilisers from entering waterways
• reducing water run-off and preventing rubbish, silt and garden waste from getting into stormwater drains
• constructing and maintaining sediment traps near waterways, especially when disturbing surface vegetation cover
• if you have a property, keeping a wide belt of vegetation around water bodies as a buffer zone for contaminants and to control erosion
• avoiding wearing insect repellents and other lotions if you go swimming in areas where frogs live.

Introduced fish species

Plague minnows

The plague minnow (Gambusia holbrookii) is a small fish sometimes called the mosquito fish. It was originally introduced to control mosquitoes but was not successful in doing this.

It is now common and widespread, and known to eat native frog eggs and tadpoles. Never introduce this fish into the wild or into a pond in your garden. In some cases, you can remove the plague minnow from a garden pond by draining it and then refilling it once the mud on the bottom has dried.

Other introduced fish species

Other exotic fish – such as trout, carp and goldfish – also eat native frog eggs and tadpoles. These species should not be used to stock garden ponds or dams that are prone to flooding. They should never be released into the wild, although trout can be released into some streams with the approval of relevant authorities.

Loss of habitat

A frog's habitat is the environment in which it feeds, shelters and breeds. If it cannot find suitable habitat it will die, so it's hardly surprising that habitat loss is probably the greatest threat to frogs.

Humans can damage frog habitat in many ways. For example, people:

• clear large areas of native vegetation for housing and agriculture
• drain wetlands or allow cattle to graze in them
• collect bush rock, which is used for shelter by some frogs such as the red-crowned toadlet
• frequently burn patches of bush which frogs shelter in
• reduce the quality of wildlife corridors, which connect areas of frog habitat. This makes it difficult for frogs to move from one area to another.

Whether you have a small garden or a large property, there are some simple things you can do to help your local frogs.

Displaced frogs

Displaced frogs, or 'banana box' frogs, have been inadvertently moved from their normal habitat, usually in containers of fresh produce or landscape supplies.

As displaced frogs pose a serious risk of spreading disease to local native species, they must be treated as if they are carrying an infectious disease and must never be released into the wild unless special approval is given.

Contact your local wildlife carer organisation or the Frog Rescue Service of the Frog and Tadpole Study (FATS) Group if you find a displaced frog. Carer groups should keep the frogs in quarantine and, after establishing they are not infected with disease, place them with licensed frog keepers.

Native frogs that you find in the wild, including in your garden, are not displaced frogs and should be left where they are.

Cane toads

The poisonous cane toad is an introduced pest that continues to spread south from Queensland, down the NSW coast. Learn how to identify them and report one if you see it!

Frog chytrid fungus

This is a deadly frog disease, which humans may help to spread. Learn how to spot a sick frog and take precautions against the fungus.