detection probability

Management of invasive mammal pests plays an integral role in the conservation of New Zealand’s native flora and fauna. Models fitted to pest capture data can guide conservation managers by providing estimates of pest densities within a management area, or probabilities of absence for declaring local eradication. A key parameter of these models is the detectability, i.e. the probability of an animal being detected by a surveillance device for a given amount of survey effort.

In order to conserve important biodiversity values, eradication of feral cats (Felis catus) is planned on Auckland Island in the New Zealand subantarctic region. This eradication will require detailed knowledge of the abundance, distribution, movement behaviour and detection probability of cats on the island. We investigated these parameters on a peninsula at the northern end of the island using live trapping, camera trapping, and scat searches with and without detection dogs. Here, we compare the results of these methods, and discuss their utility for the planned eradication.

Since their liberation in 1807, feral pigs (Sus scrofa) have negatively impacted ecosystem health and processes on subantarctic Auckland Island, New Zealand. Eradication of invasive alien species is often critical to restoration programmes and preventing species extinctions. Eradication programmes utilising multiple techniques have allowed feral pig eradications on large islands. Protracted eradication programmes can have a higher risk of failure due to factors such as biological, logistical, social, and funding support.

Estimating the detection probability of introduced organisms during the pre-monitoring phase of an eradication effort can be extremely helpful in informing eradication and post-eradication monitoring efforts, but this step is rarely taken. We used data collected during 11 nights of mark-recapture sampling on Aguiguan, Mariana Islands, to estimate introduced kiore (Rattus exulans Peale) density and detection probability, and evaluated factors affecting detectability to help inform possible eradication efforts.