Land policies should consider disease risk, study finds

Efforts to expand woodland in Scotland should consider potential infection spread between wildlife and livestock, research suggests.

Careful planning is essential when designing environmental policies, such as woodland management schemes, to control the risk of disease spread, a study suggests.

An economic data model has been developed to explore how woodland planting subsidies might alter landscapes, deer populations and the proximity of wildlife to cattle farms.

The study focused on south-west Scotland, where intensive cattle farming sits alongside existing woodland and wild deer populations.

Roslin researchers found that under a range of modelled woodland expansion scenarios, connectivity between deer habitat and cattle grazing areas could rise by up to 35 per cent, possibly leading to an increase in disease transmission between wildlife and livestock.

The work examined the possible implications for the transmission of bovine tuberculosis, although the model could be applied to any infectious disease that can spread between wildlife and livestock, the team explains.

The findings do not suggest woodland creation should be reduced, but instead highlight the importance of considering where woodland is planted and how it may affect overlap between wildlife habitats and cattle grazing areas when designing environmental policies, such as land management schemes.

Modelling approach

The study area contains large cattle herds close to woodland, enabling the model to draw on cattle tracing records and estimates of deer populations to examine how changes in land use could affect interactions between wildlife and livestock.

Researchers combined economic modelling with land use, cattle movement and wildlife distribution data to predict where subsidies encouraging woodland creation for biodiversity and climate goals were most likely to be taken up. They then assessed how new woodland could change the overlap between deer and cattle populations.

Wild deer and cattle grazing together in a field — Woodland expansion near farmland may result in increased interaction between wildlife and cattle.

Policy implications

This model could help policymakers identify areas where woodland creation may carry a higher disease risk, while supporting planting in lower-risk locations.

Potential measures to reduce the risk of disease transmission were also tested, including creating buffer zones between woodland and grazing land, or directing subsidies towards areas further from livestock holdings.

The research team is now extending the model to cover all of Scotland, and to explore how different policy measures might reduce potential risks.

This research was published in the Journal of Environmental Management, in collaboration with colleagues from the University of Glasgow.

Woodland expansion brings many benefits, including biodiversity gains and carbon sequestration, but it is important to understand any unintended consequences for livestock disease risk.
“Our work suggests there is value in considering where woodland is planted, so that environmental goals can be achieved while minimising the potential for increased contact between wildlife and farmed cattle.

Climate change and biodiversity loss are two of the great challenges of our time. Unfortunately in our efforts to combat them, we can inadvertently increase the risks of infectious disease transmission. Our research identifies an approach by which the characteristics of the risk can be identified. In this case, we show that increased contact between wildlife and livestock, rather than simply increase in wildlife density itself is a more likely route to emergent infection problems - and this is the first step to anticipating and potentially preventing them from occurring.

Modelling approach

Policy implications

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