Regulation and social licence underpin layered protection of inhabited islands

Imogen Bassett

Head of Natural Environment Specialist Services, Auckland Council

Over half the islands in Tamaki Makaurau Auckland’s Hauraki Gulf are free of introduced mammals, due to huge advances in mammalian eradications over the last 60 years. The remaining islands pose different challenges, with significant resident human populations (over 9,000 in the case of Waiheke Island), swelling by thousands more visitors and tourists each summer.
Not only are different techniques required for achieving mammalian eradications on inhabited islands, but the suite of species requiring management, to achieve comprehensive ecological protection, is also much more diverse, including latent and emerging threats from garden plants, pets and a variety of hitchhiking or self-dispersed taxa.
A Swiss cheese model of protection is required, from risk reduction at ultimate and proximate source locations through to detection and response on-island, and site-led/asset-based management for taxa that cannot be prevented or eradicated.
Aotearoa New Zealand’s Biosecurity Act provides a suite of regulatory tools that can be used to support action throughout these layers of protection. Among other things, the Act provides for powers of inspection, regulation of trade and breeding of pest taxa, stopping movement of pests or risk goods, ability to direct individuals or landowners to take pest management actions or refrain from actions that exacerbate pest risks, and powers to enter private property to search for or control pest animals.
However, regulatory tools are fundamentally underpinned by social licence; how we communicate and with work island communities and indigenous peoples is the lynch pin in effective regulation and delivery of island biosecurity. Social science-informed behaviour change strategies seek to understand, validate and work with their audience’s values and priorities, rather than assuming fact provision is synonymous with behaviour change.

Regulation and social licence underpin layered protection of inhabited islands

Keith Broome

Over half the islands in Tamaki Makaurau Auckland’s Hauraki Gulf are free of introduced mammals, due to huge advances in mammalian eradications over the last 60 years. The remaining islands pose different challenges, with significant resident human populations (over 9,000 in the case of Waiheke Island), swelling by thousands more visitors and tourists each summer.
Not only are different techniques required for achieving mammalian eradications on inhabited islands, but the suite of species requiring management, to achieve comprehensive ecological protection, is also much more diverse, including latent and emerging threats from garden plants, pets and a variety of hitchhiking or self-dispersed taxa.
A Swiss cheese model of protection is required, from risk reduction at ultimate and proximate source locations through to detection and response on-island, and site-led/asset-based management for taxa that cannot be prevented or eradicated.
Aotearoa New Zealand’s Biosecurity Act provides a suite of regulatory tools that can be used to support action throughout these layers of protection. Among other things, the Act provides for powers of inspection, regulation of trade and breeding of pest taxa, stopping movement of pests or risk goods, ability to direct individuals or landowners to take pest management actions or refrain from actions that exacerbate pest risks, and powers to enter private property to search for or control pest animals.
However, regulatory tools are fundamentally underpinned by social licence; how we communicate and with work island communities and indigenous peoples is the lynch pin in effective regulation and delivery of island biosecurity. Social science-informed behaviour change strategies seek to understand, validate and work with their audience’s values and priorities, rather than assuming fact provision is synonymous with behaviour change.

Mexico’s approach: Comprehensive island restoration

Luciana Luna Mendoza

Grupo de Ecología y Conservación de Islas (GECI)

For nearly three decades, Mexico has systematically advanced the ecological restoration and protection of its 4,110 islands, recognizing their critical importance to national sovereignty, biodiversity, and sustainable development. These islands are biodiversity hotspots, harbouring 8.3% of the nation’s vascular plants and terrestrial vertebrates and 4% of its endemic species. They are also home to 360,000 residents whose livelihoods are intrinsically linked to the health of these insular ecosystems. Eradications of invasive mammals have been central to island restoration in Mexico, with 60 populations removed from 39 islands. These efforts have protected 206 endemic species and 227 seabird breeding colonies. In some cases, post-eradication measures, such as vegetation and seabird population restoration, have been crucial for ecosystem recovery. Beyond ecological gains, the program has generated socio-economic benefits and institutional growth, including the National Strategy for the Conservation and Sustainable Development of the Mexican Insular Territory, a National Island Biosecurity Program, the legal protection of all Mexican islands, and the formation of specialized personnel at the highest levels. This long-term effort, along with environmental education, has contributed to the social construction of a conservation and biosecurity culture among island communities and government officials. Led by Grupo de Ecología y Conservación de Islas (GECI) and with Mexico’s federal government support, this overarching program was recognized in 2025 as a World Restoration Flagship by the United Nations. Islands are now a priority and part of Mexico’s first National Environmental Restoration Program. Future goals include eradicating invasive mammals from remaining islands by 2040 (about 70 eradications on 34 islands. While Mexico’s successful approach has attended the country’s unique historical, cultural, social, and economic contexts, there might be useful experiences and lessons learnt for other regions and countries.

How predator free New Zealand has captured the hearts and minds of New Zealanders

Jessi Morgan

Cheif Executive, Predator Free NZ Trust

Predator Free New Zealand represents one of the most ambitious conservation goals in the world: the eradication of introduced mammalian predators from mainland Aotearoa. While New Zealand has pioneered island eradications, extending this success across diverse landscapes and communities presents a new and complex challenge. Since the government announced the Predator Free 2050 goal in 2016, public enthusiasm and participation have grown dramatically, revealing strong national alignment with the vision of restoring native biodiversity.

The Predator Free New Zealand Trust, established in 2013, has played a central role in inspiring and mobilising communities to contribute to this mission. This presentation will explore key lessons from over a decade of engagement—how trust, shared language, accessible tools, and recognition of local effort have empowered citizens to take ownership of conservation.

By making conservation part of everyday life and positioning it as a shared societal responsibility, the predator free goal has succeeded in transforming a national aspiration into a community-driven movement that supports Aotearoa’s unique wildlife to flourish in our forests, farms and cities.

Fight for our whakapapa : Exotic Caulerpa The Seafloor Coloniser

Nicola Rata-MacDonald

Tumu Whakarae, Ngāti Manuhiri Settlement Trust

This abstract explores mana whenua perspectives on the cultural and ecological impact of the invasive seaweed Caulerpa brachypus and Caulerpa parvifolia in the Hauraki Gulf, with a focus on the experiences and responses of Ngāti Manuhiri since its discovery in 2023. As kaitiaki (guardians) of the moana, Ngāti Manuhiri view the spread of exotic Caulerpa as a direct threat to the mauri (life force) of the marine environment and to their cultural identity, which is intrinsically tied to traditional harvesting practices, intergenerational knowledge, and whakapapa (genealogy) connections to the seabed and coastline. The presence of Caulerpa has significantly disrupted customary gathering of kaimoana, particularly in the waters around Aotea (Great Barrier Island) and Kawau Bay, where dense mats of the seaweed have smothered vital habitats such as pāua, kina, and mussel beds.
Ngāti Manuhiri have led and collaborated on various strategies to remove, reduce, and eliminate Caulerpa from their rohe moana. These include direct physical removal trials, the use of weighted mats to smother the weed, and the implementation of rāhui (temporary prohibitions) to protect impacted areas while supporting scientific and cultural research. The Ngāti Manuhiri Settlement Trust has also worked in partnership with government agencies and marine scientists, advocating for Indigenous leadership in biosecurity responses and incorporating mātauranga Māori alongside Western science. Public education campaigns have been deployed to prevent the unintentional spread of Caulerpa via boats and fishing gear.
The ongoing incursion of exotic Caulerpa in the Hauraki Gulf is not only a biodiversity crisis but also a cultural one. Mana whenua responses underscore the importance of Indigenous-led environmental management and the integration of traditional knowledge systems in efforts to restore the mauri of the marine ecosystem for future generations.

Past, present and future of DOC’s approach to mammalian pest management

Stephanie Rowe

Deputy Director – General Biodiversity, Department of Conservation

Invasive alien species are one of the biggest threats to Aotearoa New Zealand’s native species and ecosystems. The Department of Conservation (DOC), mana whenua, other agencies and many New Zealanders work across public, rural and urban lands and make significant investments in invasive species management, especially mammalian pests. I will present on the past, present and future of our approach to mammalian pest management.

After an invasive species has established, eradications provide the best biodiversity outcomes of all interventions. Aotearoa New Zealand is a leader in eradicating mammals and can draw on more than 60 years of experience in removing invasive mammals from more than 100 islands. Successful island eradications and biosecurity have created over 35,000 ha of mammalian pest free habitat and have led to the establishment of
invaluable refuges for our most vulnerable species. However, eradication is only feasible when reinvasion can be prevented, or incursions managed effectively. This is currently only possible on islands or in mainland sanctuaries with pest-proof fences. On the mainland, repeated large-scale suppression operations remain the main tool to reduce the negative impact of invasive mammals, but we’re getting closer to holding large mainland areas free of predators.

In 2016, the New Zealand government launched the Predator Free 2050 programme (PF2050) with the aim of eradicating mustelids, rats and possums from the whole country. DOC leads this programme and is now implementing a revised strategy that builds on existing knowledge from island eradications and lessons learned from the first phase of PF2050, which increased public engagement with predator control and initiated
the research and development of tools and techniques within landscape-scale predator control projects.

The challenge is to identify knowledge and capability gaps and transfer existing practical knowledge gained from eradications, landscape-scale suppression work, Mātauranga Māori and community projects to the mainland while simultaneously driving research to achieve the goal at an unprecedented scale and level of ecological and social complexity.
Protecting gains obtained in the past, present conservation work and investments into the future will allow for achieving the overarching goal of protecting and restoring Aotearoa New Zealand’s unique biodiversity.

Good grief! Unexpected consequences of mammal eradications from islands off northeastern Aotearoa New Zealand

David Towns

Alien (non-native) invasive species are almost always removed from islands to enable the recovery of native species and ecosystems. Management after these eradications can range from passive recovery through to recolonisation and active restoration involving multiple reintroductions. Such initiatives also come with many questions, one of which is: What does passive recovery teach us about the way island ecosystems function? Here I discuss the results of long-term studies after a range of invasive mammals were removed over 27 years from the Mercury Islands archipelago. In a localised example, shoreline inhabiting diurnal shore skinks increased in distribution and abundance on Korapuki Island for a decade, which apparently illustrated hitherto unexpected release from the previous effects of rats. The response then reversed, most likely due lag effects after the subsequent recovery of an avian predator. Broader ecological responses were demonstrated by the recovery by populations of burrowing seabirds, which in the Mercury Islands was also more rapid than expected. This in turn can have subtle effects at multiple scales, including increases in the complexity of invertebrate food webs, changes in the diversity of nearshore marine algae, and increased seabird numbers in the far Pacific. However, our understanding of seabird engineering effects on terrestrial ecosystems is limited by island size. On large islands with old-growth forests the effects of seabird colonies appear to be localised and complicated by modifying effects from the forests themselves. Unfortunately, financial resources available for increasingly ambitions eradications rarely support studies of the ecological processes associated with subsequent recovery. Consequently, defining endpoints for management can require navigating an increasingly turbulent sea of value judgements.

Emerging technologies to improve the efficiency and feasibility of restoring islands through invasive mammal eradication

David Will

Director of Impact and Innovation, Island Conservation

The removal of invasive mammals from islands remains one of the most effective conservation interventions for preventing biodiversity loss and restoring globally unique island-ocean ecosystems. Yet, most eradication efforts to date have been implemented on small, uninhabited islands using a limited set of methods—primarily broad-spectrum toxicants and hunting or trapping—developed over the past several decades. These methods are often challenging or infeasible on islands with significant human populations, sensitive native species, limited aerial broadcast capacity, or stakeholder resistance. Multi-method eradications face additional challenges, particularly in detecting and removing the last remaining individuals. Furthermore, long-term outcome monitoring is constrained by the logistical and financial demands of repeated sampling on remote islands. In response, the past decade has seen a surge in both incremental and transformative innovations aimed at improving the feasibility, efficiency, and scalability of island restoration efforts. At the same time, technologies in remote internet connectivity, artificial intelligence, and genetics have emerged. We review key areas where innovation is most urgently needed, highlight emerging tools that are ready for broader use, and identify methods expected to be testable within the next decade. We also examine persistent barriers to adoption, including regulatory, technical, and social constraints. Given that transformative, species-specific solutions are unlikely to be globally available in the near term, we argue that conservation practitioners should prioritize safeguarding the existing toolkit while integrating proven, emerging technologies to shift eradication paradigms within their local contexts. Finally, we propose the adoption of an “application usability level” framework to standardize communication about the maturity of new tools and recommend building capacity in data science and genetics to support the development and deployment of next-generation eradication methods.