Biosecurity network interventions

  • Auckland Harbour. Image - Pike Brown
  • A beekeeper inspects a hive. Image - Linda Newstom-Lloyd
  • Salad field. Image - © Plant & Food Research

Project 2.1

Leader: Professor Phil Hulme, Lincoln University

Mission Statement

Entry and spread of pests, weeds, and pathogens into NZ is a major cause of the decline of key components of NZ’s biological heritage, including the profitability of agricultural output, access to export markets, and the population viability of native and taonga species.


In April 2000 the Varroa mite was discovered in beehives in Auckland. For several months authorities worked to stop the spread of this external parasite of honeybees that threatens the viability of hives.

Yet, despite the best efforts of government and industry, the mite spread across the Cook Strait and by June 2009 authorities conceded that getting rid of the mite in New Zealand was no longer a realistic option.

“Varroa highlighted that successful containment of incursions requires an understanding of how humans, in this particular case beekeepers, can inadvertently spread pests over long distances within New Zealand,” says Philip Hulme, Professor of Plant Biosecurity at the Bio-Protection Research Centre, Lincoln University.

A better understanding of the human-assisted networks that underpin the spread of biosecurity threats, such as Foot and Mouth Disease, kauri dieback, didymo and velvetleaf, is a critical missing piece in managing biosecurity risks once they have reached our shores.

“In New Zealand we are very good at border security and stopping known pests from getting into the country, but we have been less successful at containing the spread of pests across the country once they arrive,” Philip says.

Philip is the lead scientist on the newly funded Biosecurity Network Interventions Project that for the first time brings veterinary scientists, plant pathologists, ecological modellers and ecologists together to address the role humans play in the post-border spread of pests, weeds and diseases.

He highlights that, “fundamentally pests do not spread out from their point of introduction in simple ways but do so along networks that reflect the movement by humans of livestock, horticultural plants, and boats.”

“If we had understood how far and frequently beekeepers move hives across New Zealand, as well as their motivations for doing so, it would have informed the response and undoubtedly questioned the feasibility of containing the pest to the North Island,” he adds.

Philip leads a team of scientists from Lincoln, Massey and Canterbury Universities as well as Scion, NIWA and AgResearch Crown Research Institutes. They have selected four human-assisted networks to illustrate how biosecurity responses can be improved through state-of-the-art science. The four networks cover the spread of Campylobacter and other diseases in poultry flocks, how lake users move pests and weeds around on their boats and angling equipment, the role of both the formal and informal trade in live plants in disseminating plant diseases, and how visitors to our natural areas might inadvertently bring with them unwanted pest species.

“We chose these four contrasting networks to ensure we can develop important generic insights that are not industry or sector specific and highlight how network approaches provide a common approach across disciplines,” says Philip.

The researchers will use existing and newly collected data to describe the networks of nodes and links across New Zealand that characterise each network.

“We can use the network approach to not only forecast what situations might occur in the future but also understand why we have been less successful in the past.” The project team is working closely with important end-users including the Ministry of Primary Industries, Department of Conservation, Regional Councils, Fish and Game, New Zealand Plant Producers Incorporated and the New Zealand Poultry Association.

The research team will also incorporate Maori perspectives by examining the movement and sharing of horticultural produce through the Tahuri Whenua network run through Massey University. In addition, the Agribusiness and Economics Unit at Lincoln University will provide economic perspectives, particularly regarding the cost effectiveness of any interventions.

“By understanding these networks we can effectively have the right kind of science post-border that we already have pre-border so we can build our science capability for incursion response to the same level as we have for prevention,” Philip says.

“There are few research projects in New Zealand that bridge such a range of disciplines in the biosecurity sphere – animal, plant, productive and non productive. There is much to be gained from people who face common challenges sharing ideas and using a common approach to manage problems.

The project will receive a total of $2,300,000 over 5 years.

To develop and implement modelling tools for freight movement, nursery trade, livestock movement, and recreational travel networks to mitigate human-assisted pest spread. These tools will permit:

  • Mapping out the generic patterns of likely introduction and spread in New Zealand
  • Identification of critical points in networks to target cost-effective intervention and surveillance
  • Increased traceability such that an outbreak could be traced back to the supplier or importer.
  1. What are the attributes of different networks that facilitate invasive species spread and establishment?
  2. Do networks span management boundaries such that a multi-stakeholder response is required?
  3. How will network structure change over time and what are the consequences for biosecurity?
  4. How can an understanding of networks help focus surveillance efforts and intervention strategies?

Tahuri Whenua is a national Māori collective aligned to the horticulture sector with a particular interest in vegetable and food production. The collective is effectively a volunteer organisation that functions under cultural parameters and operates using first principles which associate Māori values to all their activities. The maintenance of a collection of plant materials (germplasm, seed, living plantations accessed for cuttings etc.) is undertaken both as a repository of economic plants for Māori and also as a hub for the distribution of plant material to ensure continuity of production and access for future generations. The Māori community generally access these materials through the collective for a broad range of purposes: home or marae gardens, community gardens, supply opportunities for special functions (e.g. marae or religious anniversaries), kura and schools and more. This project will look at the element of exchange of crop material (seed or cuttings as in kumara or taewa) through the collective hub with a view to better understanding the role of key foods in Māori society, purpose of exchange, volume, and geographical/spatial effect. The understanding gained will allow a better perspective of the role of tradition and culture in the movement of plants and foods throughout Māori society and how this practise can be understood with a view to minimising the unwitting distribution of plant related issues through cultural processes. From a network perspective the issues this component will address include:

  1. The major providers and recipients of different horticultural taxa within your network, are these flows symmetric or asymmetric, are some members major hubs for distribution nation-wide while others supply material only locally?
  2. The fate of material exchanged e.g. is it consumed within a short period, stored locally for any length of time or planted?
  3. How the structure of these flows of goods vary seasonally and with the specific products e.g. is the pattern of kumara exchange very different from potatoes?
  4. Perceptions among providers and recipients of how movement of horticultural material might spread pests and diseases, their own experience of these problems and their gut feelings as to whether pests have been introduced through such exchanges.
  5. Attitudes towards mitigating pest outbreaks e.g. MPI vs traditional approaches to containment, importance of horticultural hygiene, development of awareness of problems

The team will be led by Professor Philip Hulme (Lincoln University), and brings together high-profile university academics (including two FRSNZ) with senior CRI colleagues to integrate fundamental and applied aspects of applying network models in biosecurity across a range of threats. Links will be made to the Bio-Protection as well as Complexity (Te Pūnaha Matatini) CoREs and the Plant Biosecurity CRC.

Dalziel P & Hulme PE (2016) A Socioeconomic Research Plan for Evaluating Possible Interventions in New Zealand Biosecurity Networks. Research Report No 338 Agribusiness and Economics Research Unit, Lincoln University

Ganley B (2016) Natural area visitor network: Suitability of existing pathogen data and opportunities for new data collection to parameterise a natural area visitor network model. Scion Research Output 57827.

Ganley B (2016) Plant nursery networks: Suitability of existing pathogen data and opportunities for new data collection to parameterise a plant nursery network model. Scion Research Output 57718.

Hidano, A., Carpenter, T. E., Stevenson, M. A., & Gates, M. C . (2016). Evaluating the efficacy of regionalisation in limiting high-risk livestock trade movements. Preventive Veterinary Medicine 133: 31 – 41.