Deer to the rescue: how browsing combats wildfires in Iberian forests

A new article in Ecological Applications reveals that browsing by deer can significantly reduce fuel for wildfire in cork oak woodlands.

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Red deer (Cervus elaphus) uses the gum rockrose (Cistus ladanifer) understory as cover but also as a source of green food when the grasses are senescent. Photo: Miguel Bugalho

Mediterranean oak woodlands, known for being the native habitat of the world’s cork trees, are increasingly at risk due to the spread of shrubs and frequent intense fires. At the same time, deer populations have surged across the Iberian Peninsula, mainly due to land abandonment and a lack of predators.

A new research study published in Ecological Applications looked at how browsing by wild hoofed animals such as deer, combined with drought, affects the likelihood and intensity of wildfires. Researchers set up an 18-year experiment in Portugal’s oak woodlands, comparing areas where deer could roam freely to those fenced off from deer. They focused on the native shrub Cistus ladanifer, which is common in the understory of these woodlands and a favourite food for deer.

The study found that drought conditions increased the number of dead shrubs, especially in areas where deer were free to browse. Drought also made these shrubs more flammable, increasing the potential for wildfires. However, the areas where deer could browse had fewer shrubs overall, resulting in lower fuel loads and less fire hazard compared to areas without browsing deer. In simple terms, while drought makes the shrubs more prone to catching fire, deer help control the amount of these shrubs. By eating the shrubs, deer reduce the overall amount of flammable material, making the woodlands less likely to experience severe fires.

Cork (Quercus suber) and holm oak (Q. rotundifolia) Mediterranean woodlands are characterised by an understory composed of shrubs and diverse grassland patches. Photo: Miguel Bugalho

This research highlights the importance of managing land and wildlife together. Allowing wild hoofed animals to roam and browse can be a natural way to reduce the risk of wildfires, even as climate change makes droughts more common. It also shows that abandoning land management can have unintended consequences, like increased wildfire risk.

In conclusion, encouraging the presence of wild deer and other hoofed animals in Mediterranean oak woodlands can be an effective strategy to help mitigate the effects of drought and reduce wildfire hazards. This approach not only benefits the ecosystem but also helps protect human communities from the devastating effects of wildfires.

Full Reference

Lecomte, X., Bugalho, M.N., Catry, F.X., Fernandes, P.M., Cera, A. & Caldeira, M.C., 2024. Ungulates mitigate the effects of drought and shrub encroachment on the fire hazard of Mediterranean oak woodlands. Ecological Applications, e2971. DOI: https://doi.org/10.1002/eap.2971.

VIAMiguel Bugalho
SOURCEInstituto Superior de Agronomia (ISA) - University of Lisbon
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ISA - University of Lisbon
The University of Lisbon’s School of Agriculture (ISA), is one of the largest and most qualified schools of graduate and post-graduate degrees in the Agricultural Sciences. Located in Lisbon, Portugal, it is internationally recognised for its research in forestry, food, and the environment.