Heterogeneity and complexity in collaborative biosecurity schemes

Plant diseases threaten ecosystem and landscape health. When new disease threats emerge they can cost millions of pounds to contain and eradicate, and their wider social costs can be several times higher. Proactive biosecurity actions, including increased hygiene and monitoring for example, can reduce this threat, but in doing so they give rise to new problems: how can a government incentivise such actions, and how can it prevent free-riding where some agents reap the global benefits of others' increased biosecurity without incurring the additional cost? Simple mathematical models offer useful insights. By setting up appropriate equations governing known costs and random benefits, and optimising strategies for both the government and for each individual agent, it is possible to show how Private-Public Partnerships (PPPs), where governments both invest in biosecurity and offer outbreak compensation to agents who do likewise, can be an effective management option. However, current models are idealised, considering identical agents and averaged interactions which do not reflect the diverse landscape of agents and networks. By engaging with stakeholders and applying a range of numerical simulations and statistical analyses, this research programme will bridge that gap and help prioritise interventions.

Our aim is to test the practicality of PPPs across a range of potential disease scenarios and stakeholder groups, by extending the existing theory to heterogeneous agents interacting in diverse and realistic ways. We will do this by addressing four linked objectives: (1) evaluate the effects of heterogeneity and landscape complexity in PPPs, (2) identify effective management policies in the face of asymmetric information in PPPs, (3) evaluate how the lasting impacts of biosecurity investments may influence the predicted best management strategies, and (4) understand how biosecurity coalitions form, and how and when they might be maintained to provide efficient global benefits.

As well as being of academic interest to the communities seeking to understand and minimise risk in complex systems subject to uncertain inputs, we will work with a range of stakeholders to translate our mathematical and numerical results into practical outcomes. Natural beneficiaries include public bodies (such as Defra, Environment Agency, Natural England and its devolved equivalents) but will also include private industry groupings (such as crop producers, arbori- and horti-culturalists, and importers). Furthermore, the general mathematical framework is flexible and wider opportunities (for example, in marine diseases and invasive species) will be explored.

Who might benefit from this research?
The research is about efficient collaboration between a government and a set of private agents (such as farms, nurseries, forests, industrial units, importers) in the interests of both national and private biosecurity. This gives a wide range of potential beneficiaries in both categories: public bodies concerned with maintaining healthy functional landscapes (including Defra, Environment Agency, Natural England and its devolved equivalents) and diverse industry groupings. With the increase of the number and variety of introduced diseases, and the challenges of climate- and land-use change, the need for creative and cost-effective solutions is likely to increase.

How might they benefit from this research?
Our preliminary results point to scenarios where a government can encourage large and effective biosecurity coalitions by a careful balance of government biosecurity investment and compensation to coalition members in the event of a disease outbreak. By predicting where this optimum strategy lies, and quantifying the added value to the overall economy, our results can be translated into practical outcomes. This cannot occur in academic isolation, and we have plans to engage stakeholders from the outset, to maintain these links as the research develops, and to consolidate impact via a collaborative hands-on workshop with a range of potential end-users including BioSS, Fera and SAMS.