SMARTIES: Surveillance and Management of multiple Risks to Treescapes: Integrating Epidemiology and Stakeholder behaviour
Lead Research Organisation:
Rothamsted Research
Department Name: Net Zero and Resilient Farming
Abstract
Tree-species in the UK are threatened by an increasing number of pests and diseases resulting in large economic, environmental and social costs. Preventing the introduction of such threats is often difficult, therefore, early detection and successful management are key areas where science can deliver. There are over 1000 threats on the UK plant-health risk register, and many are serious pests of tree species. A tree-host may therefore face more than one threat at once. There have been previous calls for more systems approaches to managing biosecurity threats but scientific research still tends to focus on single species, ignoring possible interactions of multiple pests/ diseases and the fact that land managers focus on managing the tree, rather than managing a pest or disease. A second facet that is often neglected by science-based approaches is the ability and willingness of managers to adopt advice on the surveillance and management of pests and diseases as well as the acceptability of different approaches in wider society. In this project, we will develop a truly interdisciplinary approach to understand the key epidemiological and human behavioural factors that govern the invasion and spread of multiple threats to tree health and so determine successful surveillance and management at a whole system level, rather than on a pest specific basis.
Emerging threats to UK ash trees (Fraxinus excelsior) offer an important case study for our research. This UK native tree species is currently impacted by Ash Dieback (ADB), a devastating disease which is reported to have caused an estimated loss of £15 billion to the UK economy. However, ash trees in the UK face a new threat from the potential invasion of the Emerald Ash Borer (EAB), Agrilus planipennis. Although not here yet, EAB is ranked in the top three most dangerous invasive pests by EFSA. Its presence has been confirmed in Russia and it is moving West. Surveillance for EAB in the context of the already well established ADB is likely to be much more challenging because of the uncertainties surrounding ADB and EAB interactions, Ash trees that may be impacted by both ADB and EAB will further complicate management decisions faced by landowners and policy makers.
Our partnership comprises expertise in (i) modelling epidemiological processes, (ii) the design of surveillance strategies, (iii) plant pathology and entomology, (iv) the human dimensions of tree pests and diseases (v) modelling of human behaviour and forest management decision-making. We bring together the ideal combination of skills to tackle the challenge of managing new and emerging pest threats. Drawing on our experience, we will develop a model of the distribution and spread of ADB and the dispersal of EAB in a spatially explicit landscape. By analysing data on the spread of EAB from the USA and Russia we will determine the effect of both natural and anthropogenic spread that can occur. This will be used to inform and validate our epidemiological model. We will integrate this model with a novel model of stakeholder behaviour based on our social science research that captures the important attitudes and behaviours that affect decisions related to surveillance and control. Stakeholder perspectives and decision-making will be modelled dynamically allowing them to realistically change over time in response to peer and external influence. The linked models will allow us to identify how best to deploy surveillance and management resource to account for the impact of environmental conditions on risk and the sociological factors that influence biosecurity knowledge, attitudes and behaviours and identify approaches to improve social acceptability of management actions. We will use our model-based analysis to co-design surveillance and management solutions with key stakeholders including Defra EAB preparedness board, EFSA, the Forestry Commission that will inform and feed into policy development.
Emerging threats to UK ash trees (Fraxinus excelsior) offer an important case study for our research. This UK native tree species is currently impacted by Ash Dieback (ADB), a devastating disease which is reported to have caused an estimated loss of £15 billion to the UK economy. However, ash trees in the UK face a new threat from the potential invasion of the Emerald Ash Borer (EAB), Agrilus planipennis. Although not here yet, EAB is ranked in the top three most dangerous invasive pests by EFSA. Its presence has been confirmed in Russia and it is moving West. Surveillance for EAB in the context of the already well established ADB is likely to be much more challenging because of the uncertainties surrounding ADB and EAB interactions, Ash trees that may be impacted by both ADB and EAB will further complicate management decisions faced by landowners and policy makers.
Our partnership comprises expertise in (i) modelling epidemiological processes, (ii) the design of surveillance strategies, (iii) plant pathology and entomology, (iv) the human dimensions of tree pests and diseases (v) modelling of human behaviour and forest management decision-making. We bring together the ideal combination of skills to tackle the challenge of managing new and emerging pest threats. Drawing on our experience, we will develop a model of the distribution and spread of ADB and the dispersal of EAB in a spatially explicit landscape. By analysing data on the spread of EAB from the USA and Russia we will determine the effect of both natural and anthropogenic spread that can occur. This will be used to inform and validate our epidemiological model. We will integrate this model with a novel model of stakeholder behaviour based on our social science research that captures the important attitudes and behaviours that affect decisions related to surveillance and control. Stakeholder perspectives and decision-making will be modelled dynamically allowing them to realistically change over time in response to peer and external influence. The linked models will allow us to identify how best to deploy surveillance and management resource to account for the impact of environmental conditions on risk and the sociological factors that influence biosecurity knowledge, attitudes and behaviours and identify approaches to improve social acceptability of management actions. We will use our model-based analysis to co-design surveillance and management solutions with key stakeholders including Defra EAB preparedness board, EFSA, the Forestry Commission that will inform and feed into policy development.
Planned Impact
Introductions of new tree-pests and diseases are increasing rapidly in the UK. The recent study of Ash dieback in Great Britain revealed its full economic cost to be £15 billion and the introduction of the pest the Emerald Ash Borer (EAB) would amplify this further and lead to the large-scale loss of ash from the British countryside Working closely with a range of stakeholders this project will deliver a set of biosecurity recommendations that acknowledge the need to manage multiple threats simultaneously, and which, crucially, are underpinned by an understanding of the interplay between both epidemiological and behavioural processes.
This project will be of benefit to:
(1) National and International Plant Health Agencies. The project team has long established relationships and advisory roles within national plant health agencies and inspectorates in the UK and internationally including Defra, Forestry Commission and the UK Plants and Seeds Inspectorate (PHSI), European Commission DG Sante and European Food Safety Authority (EFSA). This will enable co-design and co-delivery throughout the project. Through our links with Defra, we will present our work at the annual APHA plant health inspectors' conference, as well as the annual APHA modelling symposium which is attended by a broad range of policy makers. Defra support the project and have been involved in the proposal development. We will engage with Defra Plant health policy through frequent ad-hoc meetings throughout the project, as well as formal annual workshops and biannual updates to the wider stakeholder group. Members of the proposal team provide regular advice to international plant health bodies. For example, surveillance advice to the European Commission and EU through membership of the EFSA Plant Health Panel, participation in the EU Scientific Network and expertise on the social dimension of tree health to the IUFRO Working Party.
(2) Horticultural trade, Land owners and managers. We are already engaged with stakeholder groups, such as the Horticultural Trades Association, in our current and ongoing projects and will ensure KE through formal and informal channels. We will provide materials to interest groups to include in their publications and present at events they organise.
(3) Members of the public. To maximise impact, results will be delivered through a ongoing dedicated project website (hosted by Rothamsted) and social media strategy. The latter will primarily be achieved through a dedicated twitter account. All research organisations (ROs) involved in the project have a long-standing public engagement activity agenda, and actively participate in Science communication events such as the annual National Science and Engineering week. We will use these types of opportunity to showcase the proposed project and so raise awareness of the issues. Rothamsted also holds public meetings 4-5 times a year to discuss contemporary scientific matters. All ROs have professional in house media teams and have experience working with national and international media, particularly on communicating trees pests and diseases. This will be further exploited to communicate and engage the public which can be very effective. The members of the proposal team are involved in the UKRI Xylella project, BRIGIT, which received over 11,000 public reports of the Xylella vector following a BBC news article.
This project will be of benefit to:
(1) National and International Plant Health Agencies. The project team has long established relationships and advisory roles within national plant health agencies and inspectorates in the UK and internationally including Defra, Forestry Commission and the UK Plants and Seeds Inspectorate (PHSI), European Commission DG Sante and European Food Safety Authority (EFSA). This will enable co-design and co-delivery throughout the project. Through our links with Defra, we will present our work at the annual APHA plant health inspectors' conference, as well as the annual APHA modelling symposium which is attended by a broad range of policy makers. Defra support the project and have been involved in the proposal development. We will engage with Defra Plant health policy through frequent ad-hoc meetings throughout the project, as well as formal annual workshops and biannual updates to the wider stakeholder group. Members of the proposal team provide regular advice to international plant health bodies. For example, surveillance advice to the European Commission and EU through membership of the EFSA Plant Health Panel, participation in the EU Scientific Network and expertise on the social dimension of tree health to the IUFRO Working Party.
(2) Horticultural trade, Land owners and managers. We are already engaged with stakeholder groups, such as the Horticultural Trades Association, in our current and ongoing projects and will ensure KE through formal and informal channels. We will provide materials to interest groups to include in their publications and present at events they organise.
(3) Members of the public. To maximise impact, results will be delivered through a ongoing dedicated project website (hosted by Rothamsted) and social media strategy. The latter will primarily be achieved through a dedicated twitter account. All research organisations (ROs) involved in the project have a long-standing public engagement activity agenda, and actively participate in Science communication events such as the annual National Science and Engineering week. We will use these types of opportunity to showcase the proposed project and so raise awareness of the issues. Rothamsted also holds public meetings 4-5 times a year to discuss contemporary scientific matters. All ROs have professional in house media teams and have experience working with national and international media, particularly on communicating trees pests and diseases. This will be further exploited to communicate and engage the public which can be very effective. The members of the proposal team are involved in the UKRI Xylella project, BRIGIT, which received over 11,000 public reports of the Xylella vector following a BBC news article.
Organisations
Publications
Brown N
(2020)
The role of passive surveillance and citizen science in plant health.
in CABI agriculture and bioscience
Hill E
(2024)
Integrating human behaviour and epidemiological modelling: unlocking the remaining challenges
in Mathematics in Medical and Life Sciences
| Description | Epidemiological modelling We have developed a host map for ash (Fraxinus excelsior) that accounts for land use type and canopy cover. This method avoids common issues of the overprediction of broadleaf species in areas of coniferous plantations and so will improve the accuracy of our model predictions. This map has been published for others to download. We have estimated the distance Emerald Ash Borer (EAB) is likely to have travelled when first detected given detection efficiency, and how this may be affected by UK conditions. This work is being drafted for publication. We developed compartmental model of ash dieback (ADB) to predict the current state of ADB in Great Britain. We estimated disease progress assuming that initial infection occurred in 2013 (when the first ADB reports were officially recorded) and assumed an annual spread of ~50 km/year. We modelled the interaction of EAB spread with ADB and found evidence that if EAB are more attracted to ADB infected trees then spread may be slowed. We highlight the need for scientific data to quantify better EAB attraction to ADB stressed and dead trees. We have developed a spatially explicit model of EAB spread that we have linked to an optimisation algorithm. In collaboration with the Forestry Commission, we have derived an entry point risk map and overlaid this with risks associated with household firewood use. Interviews with firewood importers revealed that imports are actively inspected, and samples taken to ensure biosecurity measures are followed, but compliance at source remains uncertain. We derived optimal sampling strategies for EAB detection for various detection devices and found that knowledge of most likely entry pathways substantially increases the chances of early detection for EAB. Ranked entry point strategies are almost as effective as optimised strategies for detection when the number of detection locations was low (less than 100) but after that substantial gains can be made by model-based optimised. This work has been submitted to the Journal of Ecology for publication and it is under review. Review A review of the literature showed the importance of ash trees across cultures and continents, including historical value, is revealed through representation in art, folklore, mythology, and place names. Ash trees are also shown to have wider social and environmental value to landscape character, biodiversity, timber uses and cultural practices. Media representations of tree pests and diseases such as ADB and EAB can be important in influencing views of the threats. Public concerns about threats to ash trees and the management of those threats are diverse, and need to be understood and considered when making decisions about management. This work was published on the Forest Research publications website (https://www.forestresearch.gov.uk/publications/values-management-and-pest-and-disease-threats-associated-with-ash-a-review/). Questionaire We developed a questionnaire to understand the attitudes and potential actions of ash stakeholders towards surveillance and management of the potential incursion of the EAB to the UK under the already established ADB threat. The survey was completed by 368 respondents and had 40 questions. Analysis of the results from the 368 completed questionnaires revealed that respondents who said ash trees were personally important to them were more likely to say they would carry out all surveillance options for EAB. Those who believed EAB would pose a high risk to ash trees elsewhere in Britain were more likely to carry out EAB surveillance options. In some cases, experience with ADB and views of ADB management were related to likely actions for EAB management. For example, participants who had seen ADB on their own trees were more likely to perform EAB surveillance and more likely to carry out EAB management. Also, those who thought that felling infected trees was acceptable for controlling ADB would be likely to fell infected trees and carry out pre-emptive felling for the management of EAB. Overall, the results help to determine likely responses to EAB, given managers' experiences with ADB, knowledge of the threats to ash trees, values associated with ash trees and other factors such as land ownership, management aims and perception of risk of the twin threats. Interviews Qualitative interviews were undertaken to understand social values and acceptability of different EAB surveillance and management options. We specifically wanted to understand how decisions were affected by multiple tree health threats, investigating current experiences of and approaches to management of ADB. To do this, we conducted 45 semi-structured interviews between August 2021 and December 2022; 10 with key informants and 35 with land managers of nine different land manager categories. Interviews with landowners showed low awareness of EAB. Currently, their expectation is that they will wait to be notified of EAB presence (rather than being involved in early detection). Ash dieback has had a profound effect on decision-making and attitudes to ash management have focussed on a 'wait and see' approach. Thus, there is a reluctance to remove un-infected trees immediately unless this becomes official advice. Strong differences in the approach to surveillance and management of ash depend on the type of stakeholder but health and safety issues showed to be one of the biggest drivers for all interviewees when managing ash. The most accepted surveillance strategy to survey EAB among all stakeholders was the use of sticky traps; however, the knowledge of EAB was low in general except for stakeholders belonging to official bodies such as tree officers and Forestry Commission surveyors. Decisions around surveillance and management actions were influenced predominantly by costs and resources, perceptions of efficacy, and availability of support. While support for different surveillance methods varied based on the land manager type, most managers were willing to engage in some sort of surveillance. Containment was less supported based on the perceived ineffectiveness of this approach for other pests and diseases, and there was widespread reluctance to undertake these actions, particularly if they were not led and partly financed by the government. There were several indications that a level of non-compliance would take place in such a scenario. Workshops Three online workshops were conducted with stakeholders who manage ash trees in some capacity from public to private and covering large to small areas of land. The workshops used a serious gaming approach, having participants roleplay through a scenario of EAB arriving in the UK. Participants made choices on how to react at key decision points before and after the beetle's arrival, followed by a short reflective discussion of those choices. Stakeholder workshops indicated clear regional differences in attitude to EAB, that appear to be driven by background levels of ADB. Those in areas with a high prevalence of the disease and longer periods with ADB in the landscape were more fatalistic about the arrival and impact of EAB. We found that while remaining ash trees were considered more valuable, this did not necessarily translate into increased intentions to manage EAB due to at times defeatist perceptions of the effectiveness of actions. As the perceptions of the severity of ADB affected perceived ability to successfully manage EAB, the predominant view was that at a certain point, it would not be worth it. We found that voluntary surveillance approaches would be constrained by resources. Smaller organisations were unwilling to invest in surveillance for a pest that is not yet present without additional support. Larger organisations would like to see a more detailed cost-effectiveness comparison of different surveillance methods. Broadly, participants look to the authorities for guidance. All our social research fed into a social model of stakeholder decision making. Socio-epidemiological modelling For the Socio-epidemiological model we focused in three areas of Great Britain: Suffolk, Kent and North Wales. These regions were chosen due to their stakeholder and treescape differences. We modelled the dynamics of each stakeholder over time using opinion dynamics modelling methods. These models simulate opinion formation within a group of interacting individuals who may also be affected by an influencing body such as extension services. We categorised the types of influencing bodies depending on the type of stakeholder undertaking surveillance or management. We found that deploying traps to high-risk locations substantially slows the spread of EAB and incentivising land managers to adopt surveillance further slows the spread. However, in our stochastic simulations only in very few instances we managed to stop the spread altogether. Overall and across the project we found that • Formal surveillance deployed according to entry hazard or optimised to maximise detection will substantially improve chances of detecting EAB before significant damage is done • If land managers adopt surveillance and management then the spread of EAB can be slowed further • Interaction with ADB has positive and negative effects on the socio-epidemic system. • Health and Safety is a key concern of many groups and tree checks will aid detection, but this form of detection is not timely • While there is general willingness around surveillance, various types of support will be needed to get widespread collaboration with different types of land managers. • For surveillance and management to be effective, clear and convincing arguments will need to be made for the needs of targeted interventions to overcome the sceptical orientation of many managers. • Land managers will be drawing on strategies, policies, practices, tools and information sources which they have already built as a result of ADB. This poses a potential opportunity for incentivisation of actions in the face of EAB. • It is unlikely that the pest will be eradicated - but it's spread can be slowed allowing mitigation strategies to be deployed. |
| Exploitation Route | The host map distribution will be of use to other researchers interested in treescapes, including Defra. The model of spatial dynamics can be used to explore wider ranges of surveillance strategy including citizen science methods, which we have started collaborating on. The conclusions from the optimised surveillance are useful to the Forestry Commission and we have discussed these with them. |
| Sectors | Environment |
| URL | https://ashtreescapes.github.io/project/ |
| Description | The model developed in this project is being used to advise Observatree on where it would be best to recruit volunteers. |
| First Year Of Impact | 2024 |
| Sector | Environment |
| Impact Types | Societal Policy & public services |
| Description | Engagement with DEFRA |
| Geographic Reach | National |
| Policy Influence Type | Implementation circular/rapid advice/letter to e.g. Ministry of Health |
| Description | Engagement with Forestry Commission |
| Geographic Reach | National |
| Policy Influence Type | Implementation circular/rapid advice/letter to e.g. Ministry of Health |
| Description | Engagement with Landmarc |
| Geographic Reach | National |
| Policy Influence Type | Implementation circular/rapid advice/letter to e.g. Ministry of Health |
| Description | Engagement with Natural England |
| Geographic Reach | National |
| Policy Influence Type | Implementation circular/rapid advice/letter to e.g. Ministry of Health |
| Description | Influenced activities of the Kent Resilience Forum Ash Dieback Strategic Co-ordinating Group |
| Geographic Reach | Local/Municipal/Regional |
| Policy Influence Type | Influenced training of practitioners or researchers |
| Impact | The Kent Resilience Forum Ash Dieback Strategic Co-ordinating Group shifted their focus to being a Tree Health Co-ordinating Steering Group, recognising the recent arrival in Kent of Acute Oak Decline and a number of other pathogens and non-native invertebrates with the potential to inflict further damage upon already climate-stressed trees . |
| Description | Quantifying the value of volunteer and landowner reports to GB plant health surveillance: a case study with ash |
| Amount | £73,213 (GBP) |
| Funding ID | Defra Future Proofing Plant Health project TH22324FR21 |
| Organisation | Department For Environment, Food And Rural Affairs (DEFRA) |
| Sector | Public |
| Country | United Kingdom |
| Start | 04/2023 |
| End | 04/2024 |
| Title | EAB spatially explicit dispersal model |
| Description | This is a spatially explicit model of EAB dispersal over the UK on a 1km x 1km resolution grid. It utilises the host distribution developed for this project and assumes two different dispersal kernels for the short and long range dispersal of the beetle due to natural dispersal ability of the beetle and human-mediated dispersal. Within each 1km x 1km a population dynamics model is integrated to describe the interaction between EAB and ash trees. The model is written in C++ |
| Type Of Material | Computer model/algorithm |
| Year Produced | 2024 |
| Provided To Others? | Yes |
| Impact | This model will be useful for modellers and researchers investigating the spread of pest and diseases in spatially explicit configurations. This model can be used to develop similar spatial models of EAB and other pests and diseases if parametrised correctly and the host distribution as well as the dynamics of populations is known. |
| URL | https://ashtreescapes.github.io/ |
| Title | Host map of Ash trees in Great Britain |
| Description | This is an Ash (Fraxinus excelsior) host map for Great Britain at the 1 km x 1 km scale. The units are in terms of ha or ash per 1km x 1km grid square. There are 100 ha in 1km x 1 km, so this can be thought of as a percent. It was created generating a 20m x 20m land use layer based on the UKCEH Land Cover Map for 2019, deriving areas of broadleaved tree cover for each cell of the land use layer and estimating the percentage of ash within broadleaf, which were assigned dependent on land use and region (see more details about the methods in data preparation and processing activities). The percentage of ash and area of broadleaf trees were combined to give an area of ash for each land use in cell and this was aggregated (summed) across all land use types to give a 1km by 1km ash area map. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2023 |
| Provided To Others? | Yes |
| Impact | The host map can be used by professionals, academics, policymakers, government on topics such as environment, tree health, monitoring, surveillance, geostatistic analysis, and modelling. This dataset provides a spatially explicit of the ash distribution across Great Britain. |
| URL | https://repository.rothamsted.ac.uk/item/98y37/host-map-of-ash-trees-in-great-britain |
| Title | Rothamsted-Models/EAB_Generate_SurvData1: V1.0.1 |
| Description | The code models the invasion and spread of the Emerald Ash Borer in Great Britain |
| Type Of Technology | Software |
| Year Produced | 2024 |
| Impact | This model has been used in the new Defra funded project on surveillance by volunteers |
| URL | https://zenodo.org/doi/10.5281/zenodo.10610811 |
| Description | Conference presentation - Presentation at IUFRO Division 7 (Forest Health, Pathology and Entomology) conference |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Other audiences |
| Results and Impact | Presentation at IUFRO Division 7 (Forest Health, Pathology and Entomology) conference, Lisbon, June 2022 Mariella Marzano presented combined findings from this questionnaire plus in-depth interviews with stakeholders |
| Year(s) Of Engagement Activity | 2022 |
| URL | https://iufro-lisbon2022.com/ |
| Description | SMARTIES webpage |
| Form Of Engagement Activity | Engagement focused website, blog or social media channel |
| Part Of Official Scheme? | No |
| Geographic Reach | National |
| Primary Audience | Study participants or study members |
| Results and Impact | SMARTIES project website - summary of the project and outcomes |
| Year(s) Of Engagement Activity | 2021,2022,2023 |
| URL | https://ashtreescapes.github.io/project/ |
| Description | Twitter channel |
| Form Of Engagement Activity | Engagement focused website, blog or social media channel |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Media (as a channel to the public) |
| Results and Impact | Twitter channel for the project |
| Year(s) Of Engagement Activity | 2020,2021,2022,2023 |
| URL | https://twitter.com/AshTreescapes |