New Zealand has 147 living native gecko and skink species (lizards) and new species are still being discovered.
The recent DNA analysis revealed 29 new species.
While a new report on the conservation status of reptiles in New Zealand shows there are more lizard species than previously thought, it also showed many of them were threatened or at risk of extinction.
Of the 147 lizard species, 59 (40%) are classed as threatened; 68 (46%) are at risk; 16 (11%) are too poorly known to assess; and just four species (3%) are not threatened.
Department of Conservation senior science adviser and report assessment panel member James Reardon said the main cause of decline was introduced predators, especially mice.
Habitat loss caused by development and effects of invasive species like wasps, ants and frogs also contributed to the decline.
More than half (54%) were estimated to be at risk of impacts from climate change.
Mr Reardon said 17 lizard species had improved in status since the last report in 2021, mostly due to better knowledge about them and management efforts.
"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 [skink] 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."
He said populations of Kapitia skink, which had been moved to a 1.3ha fenced enclosure and small experimental leaky-fenced areas on the West Coast, were 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."
However, numbers of Sinbad skinks in Fiordland had dropped in the past five years and extensive searches of its alpine habitat had shown it had gone from areas where it once lived, Mr Reardon said.
"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."
More effective control tools needed to be developed to protect lizards from mice.
The report noted that predator control targeting rats, possums and stoats was unintentionally resulting in lizard populations declining, because mice populations tended to increase when large predators were removed.
