Invasive Species Management in Island Ecosystems

Island ecosystems rank among the world’s most biodiverse yet fragile environments. Their isolation has fostered unique assemblages of endemic species, but this same isolation renders them exceptionally vulnerable to biological invasions. Introduced predators, herbivores, pathogens and weeds can drive native fauna and flora to extinction, degrade ecosystem services and undermine local livelihoods. Effective management combines rigorous prevention measures, early detection, rapid response and long-term control or eradication efforts. Biosecurity protocols at ports and airports are central to preventing new introductions, while surveillance networks and community engagement enable swift action when incursions occur. Advances in spatial prioritisation and modelling support the design of cost-efficient eradication campaigns, aligning technical feasibility with socio-political considerations. Successful island restoration often hinges on archipelago-wide approaches, reducing reinvasion risks by treating source populations holistically. Emerging research emphasises adaptive management, integrating ecological monitoring and socio-economic evaluation to maximise conservation returns under climate change and other global pressures. Practical examples—from rodent removal on subantarctic islands to large-scale mammal eradications in tropical archipelagos—demonstrate both the potential and the challenges of scaling up interventions. International collaboration and knowledge exchange remain vital for refining best practices and securing the resilience of island biodiversity in a rapidly changing world.

Research from Nature Portfolio

Global synthesis of invasive vertebrate eradication efforts has quantified over a century of interventions, revealing an 88 per cent success rate across nearly a thousand islands. Activity peaked in the mid-2000s, driven largely by rodent removal, while the area treated continues to rise as projects grow in complexity and scale. This work underscores the value of eradicating key mammalian invaders to reverse biodiversity declines and build ecosystem resilience. Complementary modelling of future extirpation risks has identified invasive rats, cats, pigs and other mammals as primary drivers of insular vertebrate loss. Simulations suggest that targeted control or removal of these invaders could prevent up to three-quarters of predicted future extinctions, with greatest benefits on small, dry islands where interactions amplify threat severity. These quantitative insights provide a basis for return-on-investment analyses, guiding prioritisation of eradication campaigns that deliver maximal biodiversity gains per unit cost.

Invasive Species Management in Island Ecosystems publication trend

The graph below shows the total number of articles in invasive species management in island ecosystems across all publications each year (not limited to Nature Index journals).

Technical terms

Invasive alien species (IAS): Non-native organisms introduced beyond their natural range that cause ecological or socio-economic harm.

Biosecurity: Measures and protocols designed to prevent the introduction and establishment of harmful organisms.

Eradication: Complete removal of an invasive species from a defined area, eliminating all reproducing individuals.

Socio-political feasibility: The likelihood that management actions can proceed successfully given stakeholder support, governance and funding.

Return-on-investment framework: Analytical approach comparing conservation benefits (e.g. species saved) to management costs to prioritise actions.

Metapopulation: A set of spatially separated populations of the same species that interact through dispersal, critical for evaluating reinvasion risk.

References

1. Invasive alien species on islands: impacts, distribution, interactions and management. Environmental Conservation (2017).
2. Archipelago-Wide Island Restoration in the Galápagos Islands: Reducing Costs of Invasive Mammal Eradication Programs and Reinvasion Risk. PLOS ONE (2011).
3. The global contribution of invasive vertebrate eradication as a key island restoration tool. Scientific Reports (2022).
4. Past and estimated future impact of invasive alien mammals on insular threatened vertebrate populations. Nature Communications (2016).
5. The threat of invasive species to IUCN-listed critically endangered species: A systematic review. Global Ecology and Conservation (2021).
6. Globally important islands where eradicating invasive mammals will benefit highly threatened vertebrates. PLOS ONE (2019).
7. Rodent eradication scaled up: clearing rats and mice from South Georgia. Oryx (2017).