Diet and habitat preferences of the Fijian crested iguana (Brachylophus vitiensis) on Yadua Taba, Fiji: implications for conservation

Morrison, Clare; Osborne, Tamara; Harlow, Peter S.; Thomas, Nunia T.; Biciloa, Pita N.; Niukula, Jone

doi:10.1071/zo07062

Cited by 8 publications

(18 citation statements)

References 18 publications

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“…data, 2006]) is intriguing. Fruits of V. amicorum are a major dietary component of iguanas and are transported by endozoochory (Morrison et al 2008). Although birds are also important dispersers of V. amicorum (Fall et al 2007), this suggests that the iguanas are having a strong impact on the composition of the vegetation on Yadua Taba (S. F. Morrison, Australian National University, pers.…”

Section: Forest Regenerationmentioning

confidence: 99%

“…For example, V. amicorum was the most common tree species on the island and was most abundant in tropical dry forest habitats. It was also the most preferred diet and perch plant species of B. vitiensis irrespective of iguana age or gender on Yadua Taba (Morrison et al 2008).…”

Section: Forest Regenerationmentioning

confidence: 99%

“…Many of these species are also abundant in limestone forest in the Lau Group (eastern Fiji [Franklin et al 2008]) and Tonga (Drake et al 1996, Franklin et al 1999, where the Lauan banded iguana, B. fasciatus, is found. Morrison et al (2008) estimated the density of the 11 plant species preferred by iguanas in different vegetation types on Yadua Taba and found that the density of these species varied over the island (e.g., density of V. amicorum ranged from 248 to 1,400 plants/ ha) but was highest in tropical dry forest habitats. Hibiscus tiliaceus and M. pinnata were the exception and were most abundant in coastal vegetation because they are primarily coastal forest species.…”

Section: Forest Regenerationmentioning

confidence: 99%

“…Morrison et al (2008) conducted a survey of the diet and perch preferences of B. vitiensis on Yadua Taba and concluded that despite the iguanas utilizing over 30 different plant species they were primarily consuming or perching in one of 11 species. These species were V. amicorum, D. elliptica, M. minutum, Hibiscus tiliaceus, Jasminum didymum, M. tiliifolius, C. insularis, E. reinwardtiana, K. platycarpum, M. pinnata, and G. americanus and were utilized in equal proportions by the different age-sex classes of iguanas.…”

Section: Forest Regenerationmentioning

confidence: 99%

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Critically Endangered Fijian Crested Iguana (Brachylophus vitiensis) Shows Habitat Preference for Globally Threatened Tropical Dry Forest

et al. 2009

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Tropical dry forests are a unique and threatened ecosystem in the Pacific and globally. In Fiji, the endangered Fijian crested iguana (Brachylophus vitiensis) is endemic to tropical dry forests. Yadua Taba Island contains one of the best remaining stands of tropical dry forest in the Pacific along with the largest (and only secure) population of B. vitiensis in Fiji and has been proposed as a translocation source for iguana conservation. In this study we determined the major vegetation types on Yadua Taba and identified forest habitat preferences of B. vitiensis to (1) characterize the island's habitats for tropical dry forest regeneration monitoring and (2) understand which forest types are preferred by iguanas for future translocation projects. Vegetation data were collected using reconnaissance, entitation, line transects, and aerial photos. Iguana abundance data were collected by nocturnal surveys of permanent transects. Six major vegetation types were identified of which tropical dry forest was the largest (46% of the island), followed by a combination of rocky cliff-shrubland/grassland vegetation (26%). Our conservative estimate of B. vitiensis population size on Yadua Taba is 12,000 iguanas, the majority of which occur in tropical dry forest. Superabundance of the dry forest understory tree Vavaea amicorum, the favorite fruit species of iguanas, may help account for the high density of iguanas observed. These results highlight the ecological link between tropical dry forest and B. vitiensis and emphasize the importance of rehabilitation or conservation of tropical dry forest habitat in potential iguana translocation sites as part of the management plan for B. vitiensis throughout the Fiji Islands.Tropical dry forest generally occurs in seasonally dry tropical regions where the average annual rainfall is less than 2,000 mm. In addition, tropical dry forests usually experience dry seasons (monthly rainfall < 100 mm) that stretch over 3 months or more (Mooney et al. 1998). In the Pacific, tropical dry forest has been recorded from Australia, New Guinea, the Solomon Islands, Vanuatu, New Caledonia, Fiji, and Hawai'i (Keppel and Tuiwawa 2007). Due to a combination of factors including fire, grazing by goats, introduction of invasive plant species, and clearing for agriculture (e.g., sugarcane, coconut, and pineapple plantations), very few, usually small, patches of tropical dry forest remain in tropical dry areas. As such, tropical dry forests are now considered one of the most endangered tropical ecosystems globally ( Janzen 1988, Lerdau et al. 1991 One of the best examples of tropical dry forest in Fiji and in the Pacific is found on Yadua Taba Island, a National Trust of Fiji Reserve in the northwest of Fiji. Over the past 25 yr, goats have been removed from the island, fires have been banned, and anthropogenic activities greatly restricted, which have increased the extent and improved the condition of tropical dry forest on Yadua Taba. In addition to having the only protected tropical dry fore...

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Section: Forest Regenerationmentioning

confidence: 99%

Section: Forest Regenerationmentioning

confidence: 99%

Section: Forest Regenerationmentioning

confidence: 99%

Section: Forest Regenerationmentioning

confidence: 99%

See 2 more Smart Citations

Critically Endangered Fijian Crested Iguana (Brachylophus vitiensis) Shows Habitat Preference for Globally Threatened Tropical Dry Forest

et al. 2009

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“…Brachylophus occur in the South Pacific Ocean archipelagos of Fiji and Tonga and are the sister clade to the rest of the iguaninae [7]. Most members of the iguaninae are large, terrestrial, and herbivorous, but the surviving Brachylophus species instead are medium sized (182–235 mm maximum snout vent length) and arboreal, with B. fasciatus (Lau banded iguana) occupying dry forests in Tonga and eastern Fiji, B. bulabula (Fijian banded iguana) occupying mesic forests in central Fiji, and B. vitiensis (Fijian crested iguana) occurring in dry forests in western Fiji [7], [8], [9]. All three species are of serious conservation concern but little is known of either B. fasciatus or B. bulabula .…”

Section: Introductionmentioning

confidence: 99%

Spatial Ecology of the Critically Endangered Fijian Crested Iguana, Brachylophus vitiensis, in an Extremely Dense Population: Implications for Conservation

et al. 2013

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The Critically Endangered Fijian crested iguana, Brachylophus vitiensis, occurs at extreme density at only one location, with estimates of >10,000 iguanas living on the 70 hectare island of Yadua Taba in Fiji. We conducted a mark and recapture study over two wet seasons, investigating the spatial ecology and intraspecific interactions of the strictly arboreal Fijian crested iguana. This species exhibits moderate male-biased sexual size dimorphism, which has been linked in other lizard species to territoriality, aggression and larger male home ranges. We found that male Fijian crested iguanas exhibit high injury levels, indicative of frequent aggressive interactions. We did not find support for larger home range size in adult males relative to adult females, however male and female residents were larger than roaming individuals. Males with established home ranges also had larger femoral pores relative to body size than roaming males. Home range areas were small in comparison to those of other iguana species, and we speculate that the extreme population density impacts considerably on the spatial ecology of this population. There was extensive home range overlap within and between sexes. Intersexual overlap was greater than intrasexual overlap for both sexes, and continuing male-female pairings were observed among residents. Our results suggest that the extreme population density necessitates extensive home range overlap even though the underlying predictors of territoriality, such as male biased sexual size dimorphism and high aggression levels, remain. Our findings should be factored in to conservation management efforts for this species, particularly in captive breeding and translocation programs.

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Nesting ecology of the critically endangered Fijian Crested Iguana Brachylophus vitiensis in a Pacific tropical dry forest

Morrison¹,

Harlow²,

Keogh³

2009

Pac. Conserv. Biol.

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Tropical dry forest (TDF) ecosystems occur throughout tropical and subtropical zones and one of their primary characteristics is that they are structurally and functionally constrained by seasonal fluctuations in moisture levels. Organisms within them synchronize growth and reproduction with water availability and many exhibit adaptations to drought conditions. We examined the previously unknown nesting ecology of the Critically Endangered Fijian Crested Iguana Brachylophus vitiensis a TDF specialist, on the Fijian island of Yadua Taba over two field seasons. In Fiji, the TDF and the endemic Crested Iguanas are threatened on a national level by anthropogenic factors and Yadua Taba Island remains the only protected site. Evaluation of adult female reproductive status revealed that only 52% of adult females reproduced in a given year. We suggest that female Crested Iguanas have adopted a biennial mode of reproduction in response to resource limitation.We found no evidence for communal nesting or nest site defence by females. All nest burrows were constructed on the forest floor in shaded areas. Mean nest temperatures (24.5�C), levels of site openness (10.9%) and total incident radiation (2.57 MJ m2 day) recorded at nest sites were less than those reported for other Iguaninae. Mean egg size (17.9 g) was large relative to most Iguaninae and was independent of the small mean clutch size (2.9 eggs). Mean incubation period was extremely long (256 days) and spanned the eight-month dry season. Mean hatching success also was high (87%). We examine reproductive strategy in relation to the environmental conditions of the TDF habitat on Yadua Taba. This research provides a broader understanding of Crested Iguana nesting ecology and is a step towards the successful implementation of the Species Recovery Plan for this species.

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Diet and habitat preferences of the Fijian crested iguana (Brachylophus vitiensis) on Yadua Taba, Fiji: implications for conservation

Cited by 8 publications

References 18 publications

Critically Endangered Fijian Crested Iguana (Brachylophus vitiensis) Shows Habitat Preference for Globally Threatened Tropical Dry Forest

Critically Endangered Fijian Crested Iguana (Brachylophus vitiensis) Shows Habitat Preference for Globally Threatened Tropical Dry Forest

Spatial Ecology of the Critically Endangered Fijian Crested Iguana, Brachylophus vitiensis, in an Extremely Dense Population: Implications for Conservation

Nesting ecology of the critically endangered Fijian Crested Iguana Brachylophus vitiensis in a Pacific tropical dry forest

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