Landcare Research - Manaaki Whenua

Landcare-Research -Manaaki Whenua

Mokomoko dryland sanctuary

An alert adult Otago skink. Image Grant Norbury.
Looking across to the experimental predator-proof fence where captive-bred Otago skinks have been thriving. Image - Grant Norbury.

Looking across to the experimental predator-proof fence where captive-bred Otago skinks have been thriving. Image - Grant Norbury.

An alert Otago skink. Image – Grant Norbury.

In 2005, the Central Otago Ecological Trust was established to restore lizard communities and the indigenous dryland habitats in which they once thrived. The Trust works near Alexandra, and is restoring a critically-endangered, strikingly-marked, flagship species, the Otago skink. Otago skinks have been locally extinct in the Alexandra basin for 40 years. They are now relegated to the western and eastern extremities of their former range and are extinct over 90% of it.

The Trust, which is chaired by Grant Norbury, recently completed a proof-of-concept experiment that demonstrated captive-bred Otago skinks will persist when released into an area free of introduced predators. In November 2009, 12 skinks were released into a 0.3 ha fenced sanctuary, and another 16 skinks were released there last December. Three of the latter group were progeny of wild skinks. This marks the beginning of the Trusts’ out-breeding programme to improve the genetic composition of the population. Three baby skinks were seen in February 2011, and another 4 baby skinks were seen last February, demonstrating recruitment into the population. Annual survival is about 80%, which is enough to hold the population steady. This is an acceptable survival rate given the small size of the sanctuary, the small founder population, and the fact that most of the skinks are bred in captivity. The Trust believes the survival rate will improve when, later this year, the fence is expanded to protect 14 ha of lizard habitat and a larger number of progeny of wild-born lizards are released. In the next few years other species like grand skinks and jewelled geckos will be included in the programme.

DOC staff and local community members after releasing 16 Otago skinks inside the predator-proof fence. Image - TV1The Department of Conservation’s (DOC) lizard conservation work at Macraes Flat in Otago suggests that, for grand and Otago skinks, it may not be necessary to exclude mice from such sanctuaries because skink numbers recover in the presence of mice. Every predator-proof fence in New Zealand struggles to exclude mice. Indeed, the Trust recently discovered mice inside its fence for the first time in 2 years. The Trust has therefore been working with Tim Whittaker (DOC, Alexandra) to design a cheaper fence that will not exclude mice. Given that a mouse was seen recently attacking an adult Otago skink inside the fence, the Trust is deliberating on whether or not to exclude mice from the new 14-ha site. In 2 years, the Trust will consider introducing grand skinks.This project is as much about people as it is about lizards. A number of volunteers and agencies are involved. Regular field days are held to restore habitat for lizards by removing invasive weeds and planting indigenous species that favour lizards. People enjoy searching for and photographing the Otago skinks, which can be individually identified by their unique golden markings. A variety of groups help out, such as school students, ecotour groups, scientists, Forest & Bird, University of the Third Age, district councils, and DOC.

Both adults and children alike are fascinated by New Zealand’s endemic lizards, shown here during one of the Trust’s field days.DOC is a major collaborator in this project and provides tremendous support for the Trust. The Alexandra Museum has a live display of Otago skinks and weekly feeding times at the Museum attract good crowds. This promotes lizard conservation, which now appears regularly in local newspapers and school curricula, and on radio and television. In addition to materials donated by businesses and cash donations by generous benefactors, the Trust has received grants from the Central Lakes Trust, the Otago Community Trust, DOC, Worldwide Fund for Nature, Transpower, and the Lotteries Commission.

The Trust has also received three awards in recognition of its work: regional winner of TrustPower’s Heritage and Environment Community Award; supreme award at the TrustPower Central Otago District Community Awards; and DOC’s Otago Conservation Award.

This work is summarised by Grant Norbury.