Lizard surveying in Aotearoa New Zealand
New Zealand has more than 100 native species of skinks and geckos which can be surveyed using a variety of methods.
Lizards of Aotearoa New Zealand
New Zealand has more than 100 species of lizards, all of which are found only in New Zealand. This is a very high diversity of lizards for a collection of temperate islands.
NZ’s native lizards include skinks and geckos. Skinks are typically ground-dwelling animals, found amongst leaf litter, decaying wood debris, and rocks. Geckos on the other hand are typically arboreal, living up in trees.
Many species are particularly vulnerable to the environmental change caused by humans and predation by introduced mammals. Most of New Zealand’s lizard species are currently threatened or at risk of extinction.
Artificial cover objects (ACOs)
ACOs are objects such as rings of wood or stacks of Onduline that are placed within an area to provide preferred habitat for skinks. ACOs are sought out by skinks because they provide shelter and protection from predators.
Once deployed, artificial retreats are typically left undisturbed for some time before being checked. ACOs are easy to use, inexpensive and minimises disturbance to lizards and their habitat and can provide information on species’ presence and population estimate.
As this method doesn’t require the handling of lizards, this tool may be suitable for those who may not have Wildlife Act permits to handle animals e.g. community groups. ACOs can also be used as a restoration tool to provide additional refuges in degraded habitats.
Pitfall traps are containers buried in the ground that allow the live capture of terrestrial fauna. Pitfall traps are commonly used to survey skinks but are less suitable for geckos which are able to climb out.
Traps can be lured with food and are checked daily, and lizards removed from the traps. Pitfall trapping can be used to provide data on distribution, abundance, species diversity, density, site occupancy, population trends, and survival estimates.
Systematic searches involving visual searches (e.g. spotlighting) and/or hand searches are generally easy to conduct and are repeatable over time. Systematic searches are particularly useful for gregarious species living in open habitats or for those with easily accessible retreats, but are not particularly useful for species that spend most of their time in the canopy or underground.
This type of survey can provide information on distribution, species diversity, abundance, population density and trends, and catch per unit effort (CPUE).
Funnel trapping is similar to pitfall trapping but consists of a cylinder with an inverted funnel in one or both ends. Animals enter through the opening and become trapped when they can’t find their way out through the opening again.
Funnel trapping can be a suitable option for trapping skinks on slopes where pitfall traps are not suitable.
They are typically partially dug into the ground so that the opening to the trap is just above ground level and baited with fruit or honey, a wetted sponge, and some debris to provide shelter for any trapped lizards.
Tracking tunnels are commonly used to monitor populations of rodents and mustelids, but they can also be used to monitor lizards.
Tracking tunnels contain pre-inked cards and a suitable attractant that lures animals through the ink and over white card where they leave footprints.
Animals can be identified to genus or species level based on the size and pattern of their footprints and this can provide an index of activity for each species or genus.
This method is more suitable for ground-dwelling lizards rather than arboreal lizards.
New and developing lizard surveying tools
Sophisticated technologies available in the modern world are being utilised to help improve lizard surveying methods. Two such tools include CritterPic and eDNA.
CritterPic is an automatic field camera developed Critter Solutions that uses AI technology to snap photos of animals of interest and delivers the images in real-time to users. Field trials to date have collected images of a variety of lizard species as well as birds, pests, and invertebrates.
eDNA sampling kits for lizards are now available from Wilderlab. These kits included an Alkathene pipe lined with a membrane which collects DNA from animals that walk across it. The membrane is removed and preserved and sent to the lab for analysis.
Habitat restoration for lizards
Lizards can be encouraged into gardens and restoration projects by creating habitats that provide suitable food and shelter.
Ground-dwelling lizards need to squeeze into crevices to escape from predators. Rocks, pipes and piles of bricks with lots of lizard-sized holes provide shelter suitable for lizards, as long as they are left undisturbed. Thick ground covers, rotting logs, vines (e.g. Muehlenbeckia) and divaricating shrubs (e.g. Coprosma) provide shelter and food for lizards.
Control of rats and mice is also very beneficial.
All lizards are protected under the Wildlife Act 1953 meaning that no one can handle or have in their possession any native lizard unless they have a permit.
For the purposes of salvage and species management, the Department of Conservation (DOC) has the authority to grant Wildlife Act Authorisations (also known as wildlife permits) that allow the permit holder to catch, hold or release certain lizard species. The permit also reduces the chance of prosecution for any accidental kills of lizards that may occur during, for example, vegetation clearance.
Wildlife permits generally require consultation with DOC and local iwi and come with specific management and reporting conditions.
Feel free to get in touch with Tītoki Landcare to discuss how we can help you with lizard monitoring, lizard salvage, Wildlife Act authorisations and designing lizard habitat.