Herpetofauna survey of geothermal ecosystems in the Waikato region

Report: TR 2022/07

Authors: Robert Brodnax

A study was undertaken using tracking cards to identify the presence of indigenous lizard populations at a few key geothermal ecosystems in the Waikato region, to establish whether native lizard populations could exist within geothermal habitats. The tracking cards also recorded prints of mammalian pest populations at these ecosystems. How pest populations varied with vegetation class and site was evaluated.

Skinks were detected in geothermal kānuka scrub at Craters of the Moon in the Taupō Volcanic Zone (TVZ), but not at any of the other sites investigated. This demonstrates that lizards can exist within geothermal habitats but does not allow us to make any assumptions about their distribution. Exotic vertebrates were frequently detected at all four sites. Depending on the location and on the species, detection of exotic vertebrates varied both with vegetation and with site. No estimates could be made of true population distributions of either lizards or pest mammals.

As lizards have been proven to have a habitat in at least one geothermal ecosystem in the TVZ, further studies into pest distribution in geothermal areas, as well as increased pest control measures for small mammals, are advised.

Further study will be necessary to identify the type and distribution of the skinks detected at Craters of the Moon, as will study to detect lizard populations at other sites in the Taupo Volcanic Zone. A more statistically rigorous sampling model could also be used in order to more accurately identify population distributions of pests at the geothermal sites.