A new report on the conservation status of reptiles in Aotearoa shows there are more lizard species than previously thought, and many are threatened or at risk of extinction.
New Zealand has 147 living native gecko and skink species (lizards) – all of which are found only here – and new species are still being discovered.
A whopping 29 new lizard species were assessed for the first time since the last report in 2021. 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.
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.
Department of Conservation Senior Science Advisor James Reardon, who was on the expert assessment panel, says 17 lizard species have improved in status since 2021, mostly due to better knowledge about them although the improved status of four is due to management efforts.
"In recent years through focussed 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 1.3 ha fenced enclosure and small experimental "leaky" fenced areas on the West Coast are also increasing.
"We've recently built a new 5 ha 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 have 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 Sinbad skink in Fiordland, numbers have dropped in the past five years, and extensive searches of its alpine habitat has shown it has gone from areas where it once was, says James.
"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 is predation from invasive mammals, especially mice. The report notes that predator control operations targeting rats, possums and stoats can unintentionally result in lizard populations declining, since mice populations tend to increase when large predators are removed. More effective control tools need 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.
