Lizard report ‘paints stark picture’

Lizards in Macraes are bucking the trend, after a new report on the conservation status of reptiles shows there are more lizard species than previously thought, and many of them are threatened or at risk of extinction.

New Zealand has 147 living native gecko and skink species (lizards) — all of which are found only in New Zealand — and new species are still being discovered.

Department of Conservation (Doc) senior science adviser James Reardon said 29 new lizard species had been assessed for the first time.

"New genomic studies by Otago University (looking at complete lizard DNA) have led to previously recognised species being split into new species, overturning our understanding of some lizards.

"Four species newly discovered in the wild (three skinks and one gecko) were also included," Dr Reardon said.

"This latest threat assessment paints a stark picture of the status of New Zealand’s native lizards.

"Of 147 lizard species, 59 (40%) are classed as threatened, 68 (46%) at risk and 16 (11%) data deficient or too poorly known to assess.

"Just four species (3%) are not threatened.

"The main cause of decline is introduced predators, but habitat loss to development and impacts of invasive species like wasps, ants and frogs also contribute. More than half (54%) are estimated to be at risk of climate change impacts."

Dr Reardon, who was on the expert assessment panel, said 17 lizard species had improved in status since 2021, mostly due to better knowledge about them, although the improved status of four was due to management efforts.

That included the status of lizards at Doc-managed land at Redbank, near Macraes.

"In recent years through focused research we’ve tested new tools such as fenced enclosures, which are improving outcomes for some of our most threatened lizard species.

"For example, grand and Otago skink numbers are recovering in an area where predators are managed at Macraes Flat in the Waitaki district and within the fenced Mokomoko Sanctuary near Alexandra.

"Populations of kapitia skink moved to a 1.3ha fenced enclosure and small experimental ‘leaky’ fenced areas on the West Coast are also increasing.

"We’ve recently built a new 5ha fenced enclosure near Reefton to protect the critically threatened Alborn skink, which has an estimated population of just 30 individuals.

"We’re hopeful this sanctuary will turn its fortunes around."

On the other hand, eight lizards had been assessed as having worse status.

"For seven species, this is due to new information improving our understanding of their situation rather than actual decline."

However, for the Sinbad skink in Fiordland, numbers had dropped in the past five years, and extensive searches of its alpine habitat had shown it had gone from areas where it once was.

"Sadly, we’ve seen a decline in Sinbad skinks, which are found in a single alpine gully in Fiordland.

"Its status has worsened to the highest threat level."

The biggest threat to lizards was predation from invasive mammals, especially mice. The report noted predator control operations targeting rats, possums and stoats could unintentionally result in lizard populations declining, since mouse populations tended to increase when large predators were removed. More effective control tools needed to be developed to protect lizards from mice.

"The discovery of lizard species is showing no signs of slowing down and people can contribute to new findings when they’re out naturing."

• Doc welcomes information about lizard sightings, especially in alpine areas or seldom-visited locations. Take photos and send reports with location details to lizardresearch@doc.govt.nz. — Allied Media