– By Lynn Adams, Technical Advisor for Biodiversity at DOC
Te Kakahu skink is a Nationally Critical lizard known from one tiny location on the remote Te Kakahu (Chalky) Island, and a newly transferred population on Anchor Island, Fiordland. But in December 2018 a new population of Te Kakahu skink was found on a remote Fiordland Islet 30km from nearest population.
Late December in 2018 our Lizard Technical Advisory Group (TAG) and staff from Te Anau District undertook a survey of lizards on Fiordland’s remote tiny islands. These islands, or islets, are so small they often only support tiny patches of wind-swept vegetation. They are seldom visited, many are exposed to the wild sea, they are steep, rocky and landings are difficult.
The trip started with a good weather so the team headed south in the DOC boat “Southern Winds” to Green Islets, south of Puysegur Point. The Green Islets are a cluster of rocky outcrops within a few hundred meters of the mainland. Wind sheared forest survives on a few of these islets but many only support low cushion plants. Its not the sort of location that you might choose for a home.
But against all odds Te Kakahu skink have managed to persist on one of these Islets. “I couldn’t believe my eyes when I lifted a rock and saw a skink sheltering in the vegetation underneath” said Ben Barr, Scientist on our Lizard TAG who was the first to find the skink. “I suspected it was a Te Kakahu skink, but I called on the rest of the team to confirm my suspicions. None of us could believe it, it was the first islet we had landed on the here was the rarest skink in Fiordland!”
After a more thorough investigation the Lizard TAG believe the population is small. “The skinks are persisting in rock crevices and in the low-lying vegetation” said James Reardon, TAG Science Advisor and expert on the species. “We don’t know why they have persisted on this tiny islet. Maybe rodents, the skinks main predator, don’t want to say on such an exposed island, or perhaps it’s just luck”.
Managing predators on this Islet is near impossible because of its remote location and difficult landing. A DOC 200 trap was set and there are plans to visit again in a helicopter, which should allow access to the very top of the island which was too steep to reach from the sea.
After sailing back to Te Kakahu Island in Chalky Sound the Lizard TAG were keen to continue their work on Te Kakahu skink. This time the aim was to determine the full range of the species on Te Kakahu Island. Previously known only from a tiny area less that 1 ha, lizard TAG members suspected their range was wider.
More rough landings were required, this time with the added risk of territorial seals defending the coast. Several teams landed and began searching for skinks. It was a hot day and perfect for skinks and all teams found skinks in the areas they were searching and the distribution on the island was expanded by several hundred metres.
The information gathered over a few days in Fiordland has made significant advances in knowledge of this rare species. We have a greater understanding of the historic distribution, the habitat requirements and can make more accurate predictions on the total population. The range expansion probably hasn’t changed this threat status, it’s still perilously rare. But with greater understanding we are better equipped to make good conservation decisions in its journey back from the brink.
You can read more about the Te Kakahu skink on our website.