CONSERVATION BACKGROUND

A shipwreck in 1918 introduced Black Rats to Lord Howe Island.  The island previously had only one native mammal (a bat) and the rats devastated the island's biodiversity – causing the local extinction of many endemic species, including the Lord Howe Island Stick Insects and six tree-nesting bird species.

By 1935, Lord Howe Island Stick Insects were considered very rare.  Further surveys failed to find any animals, and the species was thought to be extinct.  In the 1960s, rock-climbers found few dead specimens on Balls Pyramid, 23km offshore from Lord Howe Island.  It wasn’t until 2001 that a dedicated survey team found live Stick Insects on the inhospitable sea stack. 

Two years after discovery, four Lord Howe Island Stick Insects were brought back to mainland Australia.  The entire captive population is descended from these four individuals.

CURRENT CONSERVATION STATUS

IUCN Red List of Threatened Species: Critically Endangered
EPBC Act (Federal): Critically Endangered
Threatened Species Conservation Act (NSW): Endangered

The one wild population of Lord Howe Island Stick Insects is under threat from:

• Stochastic events: with such a small population, one random event (e.g. a rock slide) could wipe out the entire population
• Illegal collection: access to Balls Pyramid is currently restricted to prevent illegal poaching
• Invasive weeds: Morning Glory, Ipomoea cairica, was enchroaching on the few shrubs that provide habitat to the population on Balls Pyramid
• Habitat disturbance: Balls Pyramid is very vulnerable to disturbance.  Access to the site is tightly restricted to protect the environment

RECOVERY PROGRAM

With such a vulnerable wild population, captive breeding is critically important for maintaining 'insurance' populations to prevent extinction of the Lord Howe Island Stick Insect. 

The Federal Government has prepared a Lord Howe Island Biodiversity Management Plan, as well as a draft national recovery plan for the Lord Howe Island Stick Insect.

Melbourne Zoo currently maintains two populations in captivity: one population is carefully managed to maximise genetic diversity while the other is 'free-ranging' and natural mate choice occurs.

In the future, captive-bred stick insects may be reintroduced to Lord Howe Island if rats are eradicated from the island. 

CONSERVATION PARTNERS

• Lord Howe Island Board
• Department of Environment, Climate Change and Water, NSW