The Fijian Ground Frog Home, The Collection, Go to Order Page, Mailing List

Introduction

The endangered Fijian ground frog (Platymantis vitianus), dreli in Fijian, is one of only two endemic amphibians in Fiji, the other being the smaller tree frog (P.vitiensis).

These frogs once lived throughout Fiji but now only survive on four mongoose-free islands: Taveuni, Gau, Ovalau and Viwa (Tailevu). A small population was recently discovered on Vanualevu, but its viability is unknown. A giant ground frog once lived in Fiji but is now extinct. Little research has been done on the frogs of Fiji and virtually nothing is known about their behaviour.

Description

These are relatively large frogs, females (85-270mm) being considered larger than males (50-110mm). They differ from the introduced cane toads in having smooth rather than warty skin. They can jump long distances and have lager fine discs, whereas cane toads have short legs and cannot jump far. They can be any shade of brown, with a white spot behind the ear drum. Some have an X marking on the shoulders or a white vertebral stripe running the length of the body.

Distribution

Ground frogs were once found throughout Fiji. Their decline may have started before European colonization as Fijians used to eat them, and the introduced rat may have also had an impact.

A survey team of USP students with funding from BP International found frogs on Ovalau, Taveuni, Gau and Viwa. They also heard unconfirmed reports of frogs being present on Koro, Laucala and Qamea and Kadavu.

Ground frogs were once found throughout Fiji. Their decline may have started before European colonization as Fijians used to eat them, and the introduced rat may have also had an impact.

Of the four islands surveyed, Gau is the only one without the introduced cane toad. Taveuni is the only island with the ground frog, tree frog and cane toad. Neither island has mongoose populations.

In 2004, two frogs were found in the national Trust's Waisali Reserve on Vanualevu, where the frog was thought extirpated. A subsequent survey recorded 9 juvenile frogs and another possible 20 frogs calling in the dense undergrowth.

On Taveuni, 131 frogs were found, with 124 on Gau and 107 on Ovalau. More and much bigger frogs were found on Gau than on the other 3 islands. The lower density on Ovalau was probably due to the increased amount of disturbed forest ad the large number of people on the island.

Habitat

Frogs are usually found in damp areas of the coastal and lowland forest floor near water, but not actually in it. Some sit in lower bushes in dense undergrowth, or hide in burrows, small depressions, rock crevices or under logs. They have been observed on the beaches of Viwa and Gau. At higher altitudes, they are often found near streams, sitting on ferns. They are rarely present near areas of human activity, such as agricultural sites, but on Viwa and Taveuni, some can be heard close to the village.

Behaviour

They are nocturnal and secretive and will sit for a long time in one position until suitable prey comes along. They eat live insects and have also been observed eating their own kind. They have a short, sharp bird-like call, which is difficult to hear. When threatened they freeze and/or inflate themselves. If captured, they excrete urine on their captor. They are good swimmers, even though they do not undergo a tadpole stage like most other frogs.

Causes of decline

Mongoose, two species of rat (R. rattus and R.norvergicus), dogs, cats, pigs, goats and cane toads were introduced by European colonists and these, along with habitat destruction have been the main agents for the decline of the dreli

It is not known what caused their disappearance from Vitilevu but indirect evidence points to the arrival of the mongoose, as no population, (except for the Waisali population) appears to coexist with the mongoose.

Fiji ground frogs do exist along with cats, rats and cane toads, but probably at lower densities. The recent survey by the BP Conservation Team found that there were generally more and larger frogs on Gau than on the other three islands with both frogs and cane toads.

Captive Breeding Programme

The people of Viwa understand that they a treasured asset in the dreli, and that is under serious threat. The chief of Viwa, Ratu Dovi, and his people decided to work with the USP Biology Department and Kula Eco Park to try to protect the population of this unique frog. Dr Craig Morley, Lecturer in Conservation Biology at USP, formulated a plan to eradicate the rats and cane toads on the island (Viwa has no mongoose). While this work is being carried out, it was considered prudent to captivate and breed the frog.

Kula Eco Park, built a dedicated breeding facility and the people of Viwa, led by their chief, transported 9 individuals to Kula in October 2004.Each of the 4 breeding chambers at Kula Eco Park is 1.8m square and equipped with a light to attract insects. The floor is covered with leaf litter and there are rotten logs and vegetation for the frogs to take refuge in. Additional food is supplied by placing over-ripe fruit in open containers that attract fruit flies, while cockroaches, bred in-house, are periodically introduced.

Little is known of the ground frog's reproductive cycle. It had been recorded that they lay 40 or so small white eggs in rotten logs in Feb/March but Kula Eco Park has just announced that a female laid 62 eggs in leaf litter in August 2005 and a second female is gravid. The eggs are 6mm in diameter and the incubation period is believed to be 4+ weeks. The eggs hatch directly into froglets. There is no tadpole stage. This is the first known captive breeding of this species.

Eco Kula Park was established in 1997 with 3 main objectives: captive breeding of endangered species, free environmental education of Fiji's children, and to display Fiji's flora and fauna. Breeding programs are funded by the owners and by visitor entry fees. Kula is the largest breeding center in the world for Fiji's Crested Iguana.

The free environmental education program has to date been attended by over 7,000 children. They are presented with a Certificate of Achievement and sent home in the hope that they will spread the word of conservation. The Park funds are classes. Contributions are also received from visitors through class sponsorship. Set in 12 acres of coastal forest, Kula Eco Park, is a world class facility set in a valley through which a bubbling stream makes its way to the Pacific Ocean. Wooden walkways and bridges take visitors through the valley and the animal enclosures, which are huge structures planted with shrubs and flowers. The walkway rise over 25 meters above the valley floor and meander through a forest filled with mature trees, vines and shrubs. More information is available at www.fijiwild.com

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