Lace Monitor (Varanus varius)

​Date Published: February 2012

Assessment Summary

The Lace Monitor (Varanus varius) is a large arboreal lizard which is found in eastern and south-eastern Australia from Cape York Peninsula (Queensland) to south-eastern South Australia. Lace Monitors occur in well-timbered areas from dry woodlands to cool temperate forests in southern Australia. They forage widely, and frequently become habituated to picnic areas and camping grounds. The lizards also frequently raid farms for poultry and eggs.

Lace Monitors are noted for laying eggs within termite mounds that are either arboreal or terrestrial. The literature is conflicting in respect to whether termite mounds are critical to the lifecycle of this species. Some authors suggest that termite mounds are used frequently where they are available, while others consider that Lace Monitors are dependent on the mounds to complete their life cycle. If termite mounds are required, the species will not establish in Tasmania because the mound-building termite species (Nasutitermes exitiosus) is not present in the State. A precautionary approach is taken in this risk assessment and it is assumed that Lace Monitors could lay viable eggs in Tasmania despite the absence of termite mounds.

Lace Monitors are protected under legislation in all Australian jurisdictions where they are present. The species is listed as vulnerable in Victoria under the Wildlife Act 1975, and is listed as rare in South Australia under the National Parks and Wildlife Act 1972. It is not listed on the IUCN Red List of Threatened Species. The species is a 'controlled animal' under the Tasmanian Nature Conservation Act 2002.

The Lace Monitor is not considered a pest species. They have not established feral populations outside their native range and no introduction attempts have been noted. There is no evidence of the species causing any major impacts on agriculture.

This risk assessment determines that there is a high likelihood that this species could establish in Tasmania, with potential for moderate impacts. The most significant impacts are likely to be predation because Lace Monitors have a broad diet of small mammals, birds, reptiles, amphibians and carrion. They are known to climb trees and raid nests to feed on birds including those species that occur in the upper canopy. Given this, there is potential for impacts on a large number of Tasmanian threatened species, such as the Swift Parrot (Lathamus discolor), Wedge-tailed Eagle (Aquila audax fleayi), White-bellied Sea-Eagle (Haliaeetus leucogaster), Orange-bellied Parrot (Neophema chrysogaster), Masked Owl (Tyto novaehollandiae castanops), New Holland Mouse (Pseudomys novaehollandiae), Spotted-tailed quoll (Dasyurus maculatus maculatus), Green and Gold Frog (Litoria raniformis), Striped Marsh Frog (Limnodynastes peroni), and the Ptunarra brown butterfly (Oreixenica ptunarra).

Competition could also occur with Tasmanian lizard species such as the Mountain dragon (Rankinia diemensis), and the Tussock skink (Pseudemoia pagenstecheri). Lace Monitors could also have an impact on poultry farms in the State because they raid farms to feed on eggs and birds. Overall the potential consequences are estimated to be moderate.

This risk assessment concludes that Lace Monitors are a serious threat to Tasmania and proposes that imports be restricted to those license holders approved for keeping serious threat species.

Assessment Documentation

  Lace Monitor (Varanus varius)   (978Kb)