Rod Hitchmough, DOC Science Advisor, tells us about efforts to recover the extremely rare Chesterfield skink from the verge of extinction.
The Chesterfield skink is an extremely rare lizard found only on the West Coast in an area of less than one hectare. It’s listed as ‘Nationally Critical’ and is perhaps the most colourful skink in New Zealand.
The species was discovered in 1994, but it wasn’t confirmed as a distinct species until 2008 by which time it was around seven years since the last one was seen.
All previous sightings of this species were located in a one kilometre radius area north of Hokitika. However in the nineties intensive dairy pasture replaced this rough farmland that had once been suitable for skinks.
In response two separate surveys were undertaken by different herpetologists. Trent Bell’s 2009 survey failed to find any skinks. The second survey by Marieke Lettink in 2013 located just two individuals. Despite the search covering a wide area, they were found in exactly the same area as in the nineties. Discovering two skinks at least confirmed some were left, so we could begin planning towards the eventual goal of recovering the species.
A project to formalise the recognition of the species and give it a scientific name is currently underway and is being led by Sabine Meltzer and Geoff Patterson, supported by Trent Bell of Ecogecko, and myself.
DOC’s Lizard Technical Advice Group, led by Lynn Adams, discussed the species with Hokitika DOC Ranger Mark Martini and Biodiversity Planner Helen Otley. As a result, requests were made for support to assess the state of the skink population and offer advice on recovery options.
A team was established (led by myself, Les Morgan, and Lynn Adams) and we have made four trips to the skink’s limited habitat area since the start of 2015. During the first three trips, impressive trapping efforts resulted in 19 captures of 17 individual skinks. Our trip in November resulted in 52 captures, including 24 new skinks.
It seems likely that the population of Chesterfield skinks totals about 40-50. None have been found away from the original site. Other suitable areas have been searched repeatedly and public reports of skink sightings are being followed up but other species of skinks are widespread in the area.
We are currently working on options for habitat restoration and predator control in the area.