Updated: Jul 28, 2021
Frogs all around the world have been seen to be declining in numbers. Let's have a look at the frogs situation in New Zealand.
New Zealand Frogs
There were 7 species of native frogs of genus Leiopelma in New Zealand. But, three species have become extinct since Europeans and animal pests set their foot in New Zealand.
Now there are only 4 species left and they are:
Maud Island frog
Leiopelma is a group of frogs that have changed very little over 70 million years. The frogs have been of scientific interest. This is because they resemble the earliest frogs that evolved 200 million years ago!
The decline in frog numbers has been attributed to the infestation of predators. Competition for food following the Polynesian settlement also played a role in their decline. Their sensitive skin absorbs chemical poisons, pollution, and disease. This makes them sensitive to environmental changes.
The native frogs do not have a tadpole stage. The embryo develops inside an egg and then hatches straight into a fully-formed frog. The young of most species are carried on the back of male frogs that facilitated birth.
Below I describe the four native frogs of the Leiopelma genus. They have been living in New Zealand for over a million years from now on.
This is the only terrestrial frog found on mainland New Zealand. It is the smallest among the other native frogs. It grows up to 37mm long. It prefers damp forests as its habitat and is globally endangered. You can find this frog in Coromandel Peninsula, Whareorino Forest, and Pureora.
Hamilton's frog is also endangered. Less than 300 individuals remain present in New Zealand. It only survives on Stephens Island in the Cook Strait where there are no predators. It is managed by the Department of Conservation there.
DOC has created a second population of these frogs on the island. This is to insure against a disaster such as fire or wiping out a sole surviving population.
This is the most widespread native frog. The species live around North Island, Great Barrier Island, and Coromandel. They are also seen in central North Island and the Raukumara Ranges.
It is a colored dark brown frog that grows up to 48 mm long.
Maud Island Frog
This frog, called Leiopelma pakeka, can be found on Maud Island in the Marlborough Sounds. It grows large, up to 50mm long, and is generally dark brown colored.
In 1997, 300 Maud Island frogs were transferred to Motuara Island. This was the first-ever translocation of a native frog between islands
The other three species of Australian frogs are of genus Litoria. They were introduced to New Zealand lands more than 100 years ago. Litoria raniformis, known as the southern bell frog, is now an endangered species that faces imminent extinction.
There are in total three introduced species of this frog in New Zealand. They are distinguished from native frogs by their loud squawks and passage through a tadpole stage.
Frogs as Pets
It is possible to get several tadpoles from a pond, bring them home, and put them into an outdoor pond. This has been reported as a successful activity by members of the public.
But keep in mind that these frogs become sick and die following infection by chytridiomycosis. Chytridiomycosis is a disease that manifests among frogs. It is transmitted by boots, clothes, or field gear of human visitors to ponds. The main carrier of chytrid is the fungus species. The disease infects keratinized tissues
The major source of frogs and tadpoles for trade is the Godley Head pond near Canterbury. Tadpoles and frogs are shipped around the country for commercial sale.
Litoria frogs are exported without regulation from New Zealand to other countries such as the United States.
This article covered four native frogs: Archey's frog, Hamilton's frog, Hochstetter's frog, and Maud Island Frog. All are endangered species, declining in numbers everywhere around New Zealand.
The other three species are of Australian origin. They have been introduced as pet animals, for sake of trade.