Species Information

Brachylophus bulabula

Species Authority

Fisher, Harlow, Edwards & Keogh, 2008

Common Name/s

Fiji Banded Iguana

Species Status

Endangered

Organism Type

Reptile

Taxonomy

Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Family: Iguanidae

Environment/System

terrestrial

Invasive Species Threat Summary

The Fijian banded iguana (Brachylophus bulabula) is classed as Endangered according to the IUCN. Prior to genetic analysis all the banded iguanas were considered to belong to a single species however the Lau banded Iguana (Brachylophus fasciatus) is now recognized as distinct from the Fijian banded Iguana (Keogh et al. 2008, in Fisher, Grant & Harlow 2012). Most previous references to iguanas in central Fiji are now attributed to B. bulabula. Little is known of the dietary requirements for this herbivorous lizard. They are sometimes found in marginal habitats of non-native plants, native hibiscus and degraded forest around resorts and ocean margins (Fisher, Grant & Harlow 2012). The highest densities of this iguana are found on Makodroga in relatively low dry forest but this is not typical habitat for the Fijian banded iguana (Fisher, Grant & Harlow 2012)

Fijian banded iguanas are found primarily on wet islands with wetter forests containing preferred plant species and are found in the central parts of Fiji including on Viti Levu in extremely remote central forest areas (Fisher, Grant & Harlow 2012). Banded iguanas are thought to persist only on several large islands in the south central area (for example Kadavu, Ovalau, and Gau) and only two islands north of Vanua Levu (Mali and Cikobia) (Fisher, Grant & Harlow 2012). Fijian banded iguanas have declined by 50% in the last few decades, are rare over their presumed range and have faced local extinctions on several islands (Fisher, Grant & Harlow 2012).

Habitat loss and introduced predators are the key factors influencing Fijian banded iguana survival. Habitat degradation in the form of urban and village development, plantation agriculture, logging and mining is an ever present threat to the Fijian banded iguana (Fisher, Grant & Harlow 2012). Exotic herbivores also take their toll on the natural habitat of the banded iguana. Domestic goats (Capra aegagrus) browse plants most palatable to iguanas (Fisher, Grant & Harlow 2012). Associated fires used to round up goats contributes to the transition from native forest to grassland (Fisher, Grant & Harlow 2012).

Introduced predators such as mongooses may be the reason for the low numbers of banded iguana on Fiji’s two largest islands (Viti Levu and Vanua Levu) (Bustard 1970; Gorman 1975, in Morely 2004). The predatory small Asian mongoose (a href=http://www.issg.org/database/species/ecology.asp?si=86&fr=1&sts=&lang=EN>Herpestes auropunctatus) has also been linked to island expatriations of the iguana. Two examples of recent extirpations are on Beqa and Druadrua where the small Asian mongoose had been introduced within the last 40 years (Fisher, Grant & Harlow 2012). Prior to this iguanas were common according to the local inhabitants (R. Fisher unpub. data, in Fisher, Grant & Harlow 2012). In addition the spread of the Indian brown mongoose (Herpestes fuscus) on Viti Levu is concerning as it is believed to be better adapted to invade remnant primary forest compared with the small Asian mongoose (Fisher, Grant & Harlow 2012).

Other predators of significance to the Fijian banded iguana include rats such as the black rat (Rattus rattus) and the Pacific rat (Rattus exulans) and cats (Felis catus). Makogai and Makodroga likely represent the largest remaining populations for the Fijian banded iguana (approximately 6 000 individuals exist on these two islands) however while the islands are mongoose-free Pacific rats are present on both islands and cats are present on Makogai (Fisher, Grant & Harlow 2012). The spread of mongooses to these refuges is a possibility and would be a great threat to iguana population stability.

The deliberate or accidental movement of the American iguana (Iguana iguana) is a possibility and it is therefore pertinent to talk about the work which has been done on the American Iguana in Fiji. Awareness campaigns (initiated by the American Iguana Eradication Task Force and the Critical Ecosystems Partnership Fund) were carried out in the region in 2010. An American Iguana Eradication Workshop was also held that year which covered biosecurity measures, inclusion of billboards at landing docks and formation of an iguana eradication team (CI 2013). An eradication strategy also formulated that year evaluated iguana capture methods and concluded that the best chance of success would be through implementing a community-based approach involving the removal of gravid and hatchling iguanas from nesting sites across three to five years (CI 2013). Telemetry studies and other research based on American iguana establishment, dispersal, habitat/food selection, population estimates and control was also conducted to remedy the paucity of information available for this invasive iguana. Further information on this research is available by referring to Status Report: The American iguana (Iguana iguana) in Fiji- May-August 2011.

Invasive Species Management Summary

There are no conservation measures in place for the Fijian banded iguana and they are not known to occur in any protected areas although they may be present in preserves on Viti Levu Island (Fisher, Grant & Harlow 2012). Designation of national park status for Makogai and Makodroga Islands would protect the iguana habitat on these islands (Fisher, Grant & Harlow 2012). A Conservation Action Plan is greatly needed for this species. Confusion with Brachylophus fasciatus and the assumption that they occur on many islands means that threats may be significantly under-represented for this species.

References

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CountryLocationTypeInvasive SpeciesCommon NameImpact Mechanism
FijiCikobia-i-LauIslandblack ratPredation (potential)
FijiCikobia-i-LauIslanddomestic goatGrazing/Herbivory/Browsing
FijiCikobia-i-LauIslandcatPredation (potential)
FijiCikobia-i-LauIslandgreen iguanaCompetition (potential)
FijiCikobia-i-LauIslandsmall Asian mongoosePredation (potential)
FijiViti LevuIslandIndian brown mongoosePredation (potential)

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An Initiative of the ACP Group, funded by the European Union under the 10th EDF