The crested iguana (Brachylophus vitiensis) is a large arboreal lizard whose SVL ranges from 83 mm (hatchlings) to 223 mm (adults).
Also known as: Fiji Crested Iguana
Local Names: Vokai, Vokaivotovoto, Saumure
Description
The crested iguana is a large arboreal lizard whose SVL ranges from 83 mm (hatchlings) to 223 mm (adults). The background colour of its body is pale green (with some black speckles) and is overlain with narrow white stripes with black-edges running across the body. Male crested iguanas have large femoral pores making it easy to tell them apart from females. The crested iguana differs from the more widespread banded iguana (B. fasciatus) in being larger and having narrower white (black-edged) stripes (see species description of B. fasciatus for more information)
Distribution
The crested iguana is currently known to be present on the islands of Yadua Taba (Bua), Macuata (Ra), Monuriki and Monu (Mamanuca Group), and on Deviulau and Waya in the Yasawa Group. There are unconfirmed populations on one or two other islands of the Mamanuca and Yasawa Groups.
Habitat Ecology and Behaviour
Crested iguanas are strongly arboreal. They are diurnal and herbivorous feeding on leaves, seeds and flowers of plants commonly found in Fiji’s Topical Dry Forest (which is also Fiji’s most endangered vegetation type). A master of camouflage, crested iguanas are difficult to spot in the forest during the day, but can be spotlighted easily at night while they are sleeping. Female crested iguanas lay 2-5 eggs in nests dug in the ground. The eggs take eight months to hatch (one of the longest incubation periods for reptiles).
Threats
The greatest threat to the existing populations of crested iguanas is habitat destruction by feral goats and wildfire and the chance introduction of feral cats and the mongoose. Predation of adults and eggs by cats, the mongoose and perhaps rats will have been responsible for the extirpation of the crested iguana on other islands. It is not possible for crested iguanas to co-exist with these introduced predators. The crested iguana populations on other islands in Fiji are declining due to habitat loss and predation and are very likely to be lost from those islands in the near future unless management can be introduced. Conservation Status
In addition to their current range, there is some evidence that crested iguanas historically occurred on the dry (north western) side of Viti Levu, throughout the Mamanucas, the Yasawas, and the dry north-western tip of Vanua Levu; but now have disappeared from much of this original range.
The Yadua Taba population of crested iguanas is the largest (more than 13,000 iguanas) and most secure population in the world. This is due to the introduction of conservation management by the National Trust of Fiji which, together with the community of the Denimanu village community on Yadua island, manages the island as a sanctuary. Together they have removed goats from the island, stopped all burning and wildfire and ensured that feral cats and mongoose are kept out. However, having only a single island with a dense population is a risky conservation strategy as a disease or particularly severe cyclone might devastate this single population.
The National Trust for Fiji has played a key role in the conservation of the crested iguana since its first discovery. In 1980, the National Trust of Fiji and the landowners of Yadua Taba Island agreed to make Yadua Taba a national sanctuary. Since then, research, captive breeding programs and educational and awareness programs have been conducted in conjunction with the Taronga Zoo (Sydney, Australia), Kula Eco Park (Sigatoka), the University of the South Pacific and other organizations. A Fijian Crested Iguana Species Recovery Plan 2007-2012 is being drawn up and implementation will be led by the National Trust for Fiji.
Remarks and Cultural Significance
In addition to their current range, there is some evidence that crested iguanas historically occurred on the dry (north western) side of Viti Levu, throughout the Mamanucas, the Yasawas, and the dry north-western tip of Vanua Levu; but now have disappeared from much of this original range.
The Yadua Taba population of crested iguanas is the largest (more than 13,000 iguanas) and most secure population in the world. This is due to the introduction of conservation management by the National Trust of Fiji which, together with the community of the Denimanu village community on Yadua island, manages the island as a sanctuary. Together they have removed goats from the island, stopped all burning and wildfire and ensured that feral cats and mongoose are kept out. However, having only a single island with a dense population is a risky conservation strategy as a disease or particularly severe cyclone might devastate this single population.
The National Trust for Fiji has played a key role in the conservation of the crested iguana since its first discovery. In 1980, the National Trust of Fiji and the landowners of Yadua Taba Island agreed to make Yadua Taba a national sanctuary. Since then, research, captive breeding programs and educational and awareness programs have been conducted in conjunction with the Taronga Zoo (Sydney, Australia), Kula Eco Park (Sigatoka), the University of the South Pacific and other organizations. A Fijian Crested Iguana Species Recovery Plan 2007-2012 is being drawn up and implementation will be led by the National Trust for Fiji.
References
Gibbons (1981);
Gibbons (1984);
Gibbons and Watkins (1982);
Harlow and Biciloa (2001);
Harlow et al. (2007);
Morrison (2003), (2005);
Keppel and Tuiwawa (2007);
Laurie et al. (1987);
National Trust Species Recovery Plan, Olson et al. (2002);
Watling (1986).
Front Page Photo: Baravi Thaman