Use of forensic genetics to detect a potential incursion of the brushtail possum onto Great Barrier Island

The brushtail possum (Trichosurus vulpecula) is a widespread introduced pest in New Zealand. Some hair and faecal remains suspected to be from a possum were found on a vehicle transport barge in port at Great Barrier Island in the Hauraki Gulf (North Island, New Zealand), an island that has historically remained possum free. So that appropriate action could be taken, we used forensic genetics to confirm the species, number, and sex of the individuals that may have disembarked at the island. We concluded that forensic samples were attributable to a single male possum that did not disembark on the island, hence no eradication response was put in place. This case study illustrates how forensic DNA analysis of wildlife remains can assist in the response to a potentially disastrous invasive event by providing information in a timely and cost-effective manner.