A Rare and Elusive Species: The Coromandel Striped Gecko [Toropuku “Coromandel”]

Amongst our encounters with the Hochstetter’s Frog and Archey’s Frog, we were almost pushed over the edge into an ecstatic nerdy meltdown when our friends (and veteran rare and elusive wildlife spotters) pointed out, not one, but two Coromandel striped geckos on our night walk.


The Striped Gecko: A Third Population on the Coromandel Peninsula

The striped gecko is considered to be one of the rarest and most restricted of New Zealand geckos. Until relatively recently it had only ever been found in two locations; Stephens Island in western Cook Strait and Maud Island in Pelorus Sound. In 1997, however, a third location was added to the list, the Coromandel Peninsula. This first gecko was found clinging to an interior wall of a family home. A second and third Coromandel striped gecko were found separately in 1999.

DSC_8531
Our first Coromandel striped gecko [Toropuku “Coromandel”] of the night

Click to zoom in

In 2007, ten years on from the first sighting, a fourth was found by DOC staff and was measured and photographed. During a two month period, the individual was held and monitored in captivity by a local reptile keeper with DOC until Animal Ethics gave the permission for a harness and transmitter to be trialed on the animal. Once permission was granted, it was released with the transmitter allowing its movements and behaviour to be monitored. The observations gained from this trial were interesting and informative, however, the study was brief with the transmitter battery lasting only 6 days. By this time a decision was made that recapturing the individual considering the length of time already held in captivity was not justified. The animal was released near the site it was originally found at.

From an outdated Department of Conservation document titled, ‘Coromandel Striped Gecko Database’, only 28 individuals have been identified and recorded up until 12th November 2014. I am not aware of any updates to the database, but know that additional animals have been found since. I can be sure of this as Emma and I with our wildlife-spotting friends, Sara and Ro, came across two presumably new individuals that night! These organisms are either extremely rare or exceedingly elusive. In fact, according to some sites, (i.e. http://www.teara.govt.nz) ‘It is considered to be the world’s rarest gecko.’

DSC_8659
Our second Coromandel striped gecko [Toropuku “Coromandel”] of the night

Click to zoom in


Why was the discovery of striped geckos on the Coromandel Peninsula remarkable?

What is remarkable about the discovery of this third population of striped geckos, is that the Coromandel Peninsula is 460 km north of the Cook Strait/Pelorus Sound populations of striped geckos, and at the opposite end of the North Island. As animals were found so far outside of their known range, doubts were originally expressed about their identity and even the authenticity of the records. An investigation was undertaken to determine if it was a possibility that individuals may have been purposfuly or accidentally released by reptile keepers in the Coromandel area. It turns out that all those who had kept striped geckos in the past no longer did, and their animals had historically passed away. In order to gather additional information, a press release was published in the local newspaper, the Hauraki Herald, requesting information from anyone having seen or kept geckos distinctively marked with longitudinal markings. Although there were two responses, neither proved to be of striped geckos. It turns out that they were not accidental or deliberate releases of animals from the Cook Strait region, but they actually represent a previously undiscovered population.

Morphometric and genetic data have since shown that the striped geckos found on the Coromandel Peninsula are conspecific with the striped geckos from the Cook Strait region.  Minor differences in the mitochondrial DNA of the Coromandel and Cook Strait animals indicate that the Coromandel striped geckos are from a distinctive population.  At this stage the differences are not clear enough to justify taxonomic distinction. Due to this understanding, it is beleived that striped geckos were probably distributed through lowland forest in the central and southern North Island, and parts of the northern South Island, and that they may still occur at other sites within this range. Historically, lowland forest structurally and floristically similar to that occupied by striped geckos was widespread in the North Island and northern South Island below 300m.

The IUCN list of threatened species classifies all three populations as Vulnerable D2, which is defined as a population “characterised by an acute restriction in its area of occupancy (typically less than 100km) or in the number of locations (typically less than 5)”. This means that they are at risk of becoming critically endangered or extinct in a very short period.

DSC_8533
Click to zoom in

Our experiences have made us feel extrordinarily lucky as DOC literature state that follow-up surveys using a variety of techniques (pit-trapping, spot-lighting and artificial cover) have thus far failed to locate further specimens. The majority of all Coromandel striped geckos found have been in non-natural habitats. We were lucky enough to see two undisturbed individuals going about their business in native bush.

It seems that there is a long way to go before we can feel that we have a good understanding of these rare and elusive creatures. In saying that, time is of the essence considering the number threats facing the Coromandel striped gecko along with other native reptiles and amphibians. These populations are at risk to predation from many introduced mammalian predators.  At the very least mice, ship rats, Norway rats, stoats and feral and domestic cats are likely to be present and having  devastating effect on their numbers.

We hope that trapping and management of mammalaian predators continues in these areas with greater resources dedicated to knowing the local predator status’, which can be used to inform decision making, in turn protecting these important native species.

Emma and I plan to return to the Coromandel and partake in future surveys gaining a greater understanding of their abundance, range and behaviour.

DSC_8545
Click to zoom in


*UPDATE* 10.04.17

After publishing this blog post on 09.04.17, we recieved new information regarding Coromandel striped gecko counts. We have now been informed that the new total sightings of CSGs sits at around 45 individuals (Smerdon, S., personal comunication, April 09, 2017). We have also been made aware of the release and further monitoring using tramitters on two CSGs that were held in captivity for 6 years. They were realeased and monitored over a 10 day period in 2006 at Driving Creek Wildlife Sanctuary (See link below).


*UPDATE* 12.05.17

We have changed the species name from Toropuku stephensi to Toropuku “Coromandel” as it is referred to in the Department of Conservation document, “Conservation status of New Zealand reptiles, 2015”. Previously, the Coromandel Goldstripe Gecko has also been referred to as Hoplodactylus stephensiHoplodactylus aff. stephensi “Coromandel”, Toropuku aff. stephensi “Coromandel”.


References and Further Reading

Chappell, R. (2007) – Striped gecko (Hoplodactylus stephensi var. coromandel) : An Ongoing update as new animals are located. DOC Document

DOC Website, Documents – http://www.doc.govt.nz/documents/science-and-technical/casn232.pdf
(Retrieved 6 April, 2017)

DOC Website, News –  http://www.doc.govt.nz/news/media-releases/2013/rare-coromandel-striped-gecko-found/
(Retrieved 6 April, 2017)

IUCN Website – http://www.iucnredlist.org/details/10253/0
(Retrieved 6 April, 2017)

Stuff Website – http://www.stuff.co.nz/environment/81078169/rare-geckos-released-into-the-wild-after-six-years-in-captivity
(Retrieved 10 April, 2017)

Te Ara Website – http://www.teara.govt.nz/en/photograph/30367/coromandel-fauna-coromandel-striped-gecko
(Retrieved 6 April, 2017)

Terranature Website – http://www.terranature.org/geckoCoroStriped.htm
(Retrieved 6 April, 2017)

Wikipedia – https://en.wikipedia.org/wiki/Stephen%27s_Island_gecko
(Retrieved 6 April, 2017)

4 Comments Add yours

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s