Ecology and conservation of the Christmas Island giant gecko

Project start date: 01/10/2023
Project end date: 30/09/2027
NESP funding: $392,700 (GST-exclusive)

The Christmas Island giant gecko (Cyrtodactylus sadleiri) is the last remaining endemic reptile found in the wild on Christmas Island, out of the 5 species the island once held. Though the Christmas Island giant gecko was common until the 1970s, little is known about this severely imperilled species. The need to obtain more information on this species is urgent and vital for its survival. The threats presumed responsible for the collapse of other lizard populations are still present on Christmas Island (e.g. predation by invasive centipedes, wolf snakes and cats) and may cause a similar collapse of the Christmas Island giant gecko population.

Christmas Island Giant Gecko with its head downward on an upright branch with its tail curling into the air.
The Christmas Island giant gecko is also known as the Christmas Island forest gecko or Sadleir’s bow-fingered gecko. Photo: JP Emery.

To effectively manage and conserve the Christmas Island giant gecko, this project will obtain up-to-date information on various aspects of the species, including its population abundance, density, spatial distribution, ecology, habitat preferences, predator interactions and genetic diversity.

Collectively, this information will provide a comprehensive understanding of the species, which will aid in the development and implementation of effective conservation strategies to safeguard its survival.

Christmas Island Giant Gecko on a pale branch with its toes spread out looking at the camera
Christmas Island giant gecko. Photo Dion Maple CC BY-NC 4.0.

Key research areas

To address the threats to the survival of the Christmas Island giant gecko, this project is:

  • assessing current population size and distribution of the giant gecko on Christmas Island
  • investigating the ecology and habitat preferences of the giant gecko
  • investigating the interactions between predators and giant geckos
  • developing and recommending an appropriate monitoring program based on comprehensive baseline data.