Polynesian rat

Lizard populations on islands with and without Polynesian rats, Rattus exulans (Peale).

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

The tuatara, Sphenodon punctatus Gray, on islands with and without populations of the Polynesian rat, Rattus exulans (Peale).

The results of a survey of the presence and populations of the tuatara (Sphenodon punctatus) and the Polynesian rat or kiore (Rattus exulans) on 35- islands off the New Zealand coast are presented and discussed. Tuataras were found on 23 of these, and on six they occur with kiore. The age distributions and densities of the tuatara populations suggest that decline because of failure of recruitment is occurring on seven—the six kiore -inhabited islands and one other.