invasive predators

Conservation programmes in New Zealand often suppress populations of a single invasive predator for the benefit of threatened avifauna. However, the establishment of whole guilds of invasive species has created complex competitor and predator-prey relationships, including some well-described trophic cascades. Trap networks designed to target stoats (Mustela erminea) are poorly optimised to supress a population of weasels (M. nivalis), and may contribute to periodic spikes in weasel numbers due to decreased interspecific competition and aggression.

Invasive predator control to protect native fauna usually takes place in native habitat. We investigated the effects of predator control across 6000 ha of multi-tenure, pastoral landscape in Hawke’s Bay, North Island, New Zealand. Since 2011, low-cost predator control has been conducted using a network of kill traps for mustelids (Mustela spp.), and live trapping for feral cats (Felis catus). Although not deliberately targeted, other invasive mammals (particularly hedgehogs Erinaceus europaeus) were also trapped.