lizard

Predator-free sanctuaries can assist the conservation of multiple endemic species, but quantitative evidence of these benefits is often lacking, especially for herpetofauna. We measured population responses of three common lizard species (schist geckos, Woodworthia ‘Central Otago’; McCann’s skinks, Oligosoma maccanni; and southern grass skinks, O. aff. polychroma Clade 5) 1 year before and 5 years after mammalian predators were removed inside a mammal-proof fence in a dry grass/shrubland habitat with abundant schist rock in Central Otago, New Zealand.

The capture of animals in live traps poses inherent risks of heat stress and mortality to trapped individuals. Despite a long history of pitfall trap use in New Zealand for monitoring small lizards, the design of traps and their covers often varies; however, the effects that this has on the internal temperature of the traps is unknown. Poor trap design may increase the risk of stress and mortality if internal temperatures exceed thermal limits.

Fruit is an important component in the diet of many lizards, but their role as seed dispersers is often overlooked. Seed retention time and animal movement determine how far a fleshy fruited seed will be dispersed from the parent plant. Seed retention times were investigated in 78 captive Hoplodactylus duvaucelii (Duvaucel’s geckos). Geckos were offered fruits from 10 plant species. Fifty-one geckos consumed fruits and the mean seed retention time was 69 hours (range 31 to 145 hours).

The number and type of threats that a species is exposed to is often influenced by their activity patterns. For ectotherms, environmental conditions are likely to strongly influence activity, given that external heat is needed to reach body temperatures that promote physiological functions, including locomotion. As a result, one might expect ectotherms to avoid cold environments, such as the alpine zone, known for large temperature variations and prolonged winters.

Temporary penning prior to release is a strategy increasingly being used in lizard translocations to improve site fidelity and increase chances of translocation success. However, it is yet to be tested on a range of lizard taxa. Between 2015 and 2018, 49 individuals of a New Zealand endemic arboreal gecko species (ngahere gecko, Mokopirirakau “southern North Island”) were translocated to mammal-free Mana Island near Wellington as mitigation for a development project.

New Zealand’s mountainous environments support unique flora and fauna specially adapted to the extreme cold and harsh conditions of the alpine zone. The orange-spotted gecko (Mokopirirakau “Roys Peak”) is a rare undescribed gecko that is currently known only from the alpine zone of Otago. The species was discovered in 1998 and is only known from the Central Otago and Queenstown-Lakes districts, with populations spanning a ~3000 km2 area.

Introduced mammalian predators threaten populations of endemic New Zealand skinks. Their effects on skink populations have been not often quantified on the mainland and are known primarily from skink population increases on islands from which mammals have been eradicated. Estimating skink population density with capture–recapture trapping is time-consuming and costly. Counting skinks in artificial retreats in specific weather conditions may be a useful and relatively quick way to index population density, but needs calibration for different habitats and species.

On three island groups off the northeast coast of New Zealand, fewer lizard species and markedly fewer individuals occurred on islands inhabited by Polynesian rats or kiore than on other islands without rats. Nocturnal, ground-dwelling lizards that forage in the open were most affected, which suggests that predation by kiore is the cause. The generally low densities and disjunct distributions of some lizards on the New Zealand mainland may have resulted from the introduction of kiore at least 600 years ago

European hedgehogs (Erinaceus europaeus) have recently been identified as a conservation threat in New Zealand. Hedgehogs were kill-trapped at 14 wetland and braided riverbed sites in the upper Waitaki Basin between late October 1997 and early February 1998 and their gut contents described. The most commonly eaten prey were Coleoptera (present in 81% of 192 guts), Lepidoptera (52%; n = 192), Dermaptera (49%; n = 192), Hymenoptera (42%; n = 192) and Orthoptera (31%; n = 319).