Distribution and detectability of mammalian pests in the Waikato Region

ABSTRACT We used systematic arrays of camera traps combined with site-occupancy analyses to estimate the site-specific presence and probability of detection the principal target pests across the three main habitats of Waikato Region, classified by season. Cameras easily identified brushtail possums, hedgehogs, ship rats, wild house mice, and mustelids, i.e., stoats, feral ferrets and weasels taken as a group. The data comprise four sets of estimates, one set of 15 (five targets, three habitats) for each season of the year, total of 60. Of these, only 10 (17%) returned probabilities of detection of more than 50% for that species in that habitat at that season, given that at least one individual was present then. All pest species we monitored were present on pastoral land. Pasture makes up more than half of the land cover of the Waikato, so it supports large numbers even of species that are not abundant in that habitat. Hence, pest control operations intended to conserve indigenous species in protected forests need to allow for the important effects of rapid reinvasions of controlled areas from adjacent pasture.