pitfall trap

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.

Inventory and monitoring of biodiversity requires effective sampling tools. Footprint tracking tunnels, developed in New Zealand to monitor small mammals, may also be useful for sampling lizards and other reptiles but more research is needed to verify this. We compared the detectability of terrestrial skinks using two methods: pitfall trapping and footprint tracking. In New Zealand, the former is the traditional method for sampling skinks, while the latter is routinely used to monitor populations of introduced rodents and mustelids.

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.