2025 Fijian Crested Iguana Report

Reintroducing Iguana Food-Plant Species to Monuriki Island, Fiji

Submitted by Peter Harlow

Taronga Conservation Society, Australia

The seedling ‘Collecting Team’ in the forest on Castaway Island.

Project Overview

This project focused on restoring critical food-plant species to Monuriki Island, Fiji—an essential location for the Critically Endangered Fijian Crested Iguana (Brachylophus vitiensis). Decades of goat grazing and repeated fires had severely degraded the island’s vegetation, leaving most native food plants locally extinct and drastically reducing available nutrition for the remaining iguana population.

To address this, the initiative aimed to reintroduce key native plant species that form the foundation of the iguana’s diet, including False Sandalwood, Lime Berry, and Beach Almond. Activities included seed collection from nearby islands, propagation in a village nursery, and large-scale transplanting of seedlings onto Monuriki. The project also sought to build local capacity for ongoing conservation work.

1) Castaway Island showing Castaway Resort on the right, with Malolo Island directly behind (photo Creative Commons). 2) Established, potted seedlings from Joeli Vadada’s home nursery in Yanuya village on their way to Monuriki Island for planting.
Manasa and Sepu collecting Ivi (Tahitian Chestnut) seedlings on Malolo Island.

Accomplishments

The project achieved significant progress in restoring critical components of Monuriki Island’s ecosystem through the successful reintroduction of native food plants essential to the survival of the Fijian Crested Iguana. Over the course of the project, seeds were collected during multiple field visits and propagated in a local nursery, resulting in the planting of 449 seedlings across priority restoration sites. These included 269 False Sandalwood, 42 Lime Berry, 78 Beach Almond, 42 Vesi Wai, and 18 Tahitian Chestnut seedlings. Notably, nearly one-third of these plants were nursery-grown for a full year prior to transplantation, increasing their resilience and likelihood of survival.

Follow-up monitoring conducted approximately one year after planting, demonstrated strong survival outcomes for several key species. False Sandalwood, the most critical component of the iguana’s diet, exceeded expectations with 173 surviving seedlings—surpassing the project’s target and marking an important milestone in habitat restoration. Beach Almond and Vesi seedlings also showed encouraging establishment, with dozens of individuals surviving and growing steadily.

While Lime Berry survival rates were lower than anticipated, the presence of surviving individuals still represents meaningful progress toward restoring dietary diversity.

Beyond survival metrics, measurable growth was recorded across all species, indicating successful establishment under challenging environmental conditions. Many seedlings showed substantial increases in height, signaling their transition toward maturity. As these plants continue to grow, they are expected to begin producing fruit within the coming years, providing a sustainable and renewable food source. Importantly, these fruiting species will also facilitate natural seed dispersal through iguanas and native birds, accelerating ecosystem recovery beyond the initial planting sites.

The project also demonstrated effective field-based restoration techniques, including careful seedling extraction, transport, and planting methods designed to maximize survival in remote island conditions. In parallel, a functioning small-scale nursery was established, and local partners gained hands-on experience in seed collection, propagation, and planting practices. While additional capacity building is needed, these efforts represent an important first step in developing local infrastructure to support ongoing conservation work.

The ‘Planting Team’ on Monuriki Island.

Future Considerations

While ecological outcomes were encouraging, the project highlighted significant challenges regarding long-term sustainability and local capacity. Future efforts will focus on continued monitoring of planted seedlings, management of invasive species, and maintenance such as fertilization to support plant establishment. Strengthening local conservation capacity and engagement will ensure lasting and sustainable impacts.

As well as translocating the seedlings, the team continues to selectively remove large Vao trees (Neisoperma oppositifolium) from Monuriki by ringbarking and herbicide, to allow more sunlight to penetrate to the forest floor along our seedling transects.