Mammalian Predator Management in New Zealand Ecosystems

New Zealand’s island biogeography and long isolation have produced a unique assemblage of native birds, reptiles and invertebrates that evolved in the absence of mammalian predators. Since human settlement, a suite of introduced mammals – including rats, stoats, possums, feral cats and mice – has driven widespread declines and extinctions of native fauna. Management efforts span eradication, sustained suppression and preventive barriers, applied at scales from small forest fragments to entire islands and mainland sanctuaries. Approaches combine trapping, toxin deployment and exclusion fencing, often within adaptive frameworks aimed at maintaining low predator densities or achieving complete removal. Key challenges include preventing reinvasion from adjacent source populations, avoiding unintended rises in secondary predators (mesopredator release) and balancing cost‐effectiveness against social acceptability. Innovative modelling and monitoring tools increasingly inform optimised trap placement, baiting regimes and spatial sequencing of control zones. Complementary strategies such as predator‐proof sanctuaries and community‐led backyard trapping have also emerged, linking ecological outcomes to public engagement. Despite significant successes in offshore islands, mainland eradication remains complex, necessitating integrated landscape approaches that account for habitat heterogeneity, predator interactions and long‐term surveillance.

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Mammalian Predator Management in New Zealand Ecosystems publication trend

The graph below shows the total number of articles in mammalian predator management in new zealand ecosystems across all publications each year (not limited to Nature Index journals).

Technical terms

Predator Free 2050: A national goal to eliminate selected invasive mammals from New Zealand by mid-century.

Mesopredator release: A rise in mid-ranking predator populations following removal of top predators, often exacerbating prey impacts.

Multirodent eradication: Concurrent removal of multiple rodent species to prevent compensatory population increases.

Landscape barrier: Physical or ecological feature that impedes movement of invasive species, used to reduce reinvasion risk.

Niche partitioning: Division of ecological roles or habitats among sympatric predators to minimise direct competition.

References

1. Small mice create big problems: Why Predator Free New Zealand should include house mice and other pest species. Conservation Letters (2024).
2. Eradicating an invasive mammal requires local elimination and reduced reinvasion from an urban source population. Ecological Applications (2024).
3. Fenced sanctuaries deliver conservation benefits for most common and threatened native island birds in New Zealand. Ecosphere (2018).
4. Niche partitioning in a guild of invasive mammalian predators. Ecological Applications (2022).
5. Public willingness to engage in backyard conservation in New Zealand: Exploring motivations and barriers for participation. People and Nature (2021).