Heterogeneity and complexity in collaborative biosecurity schemes

植物病害威胁着生态系统和景观健康。当新的疾病威胁出现时，控制和根除它们可能要花费数百万英镑，其更广泛的社会成本可能高出数倍。积极主动的生物安全行动，例如加强卫生和监测，可以减少这种威胁，但这样做会产生新的问题：政府如何激励这种行动，如何防止搭便车，一些机构在不承担额外成本的情况下从其他机构的生物安全加强中获得全球利益？简单的数学模型提供了有用的见解。通过建立适当的方程来控制已知成本和随机收益，并优化政府和每个个体代理的策略，就有可能展示公私合作伙伴关系（ppp）是如何成为一种有效的管理选择的。公私合作伙伴关系是指政府既投资于生物安全，又向同样投资的代理提供爆发补偿。然而，目前的模型是理想化的，考虑了相同的代理和平均的相互作用，这并不能反映代理和网络的多样性。通过与利益攸关方接触并应用一系列数值模拟和统计分析，该研究计划将弥合这一差距，并帮助确定干预措施的优先次序。我们的目标是通过将现有理论扩展到以不同和现实的方式相互作用的异质因子，在一系列潜在疾病情景和利益相关者群体中测试ppp的实用性。我们将通过解决四个相互关联的目标来实现这一目标：(1)评估ppp中异质性和景观复杂性的影响；(2)在ppp中面对信息不对称时确定有效的管理政策；(3)评估生物安全投资的持久影响如何影响预测的最佳管理策略；(4)了解生物安全联盟是如何形成的，以及如何以及何时维持它们以提供有效的全球效益。除了对寻求理解和最小化受不确定输入影响的复杂系统风险的社区有学术兴趣外，我们还将与一系列利益相关者合作，将我们的数学和数值结果转化为实际成果。自然受益者包括公共机构（如Defra，环境署，自然英格兰和其权力下放的对等机构），但也将包括私人工业集团（如作物生产者，树木和园艺者，以及进口商）。此外，一般数学框架是灵活的，将探索更广泛的机会（例如海洋疾病和入侵物种）。

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.