Horses play a key role in forest management and in reducing the risk of wildfires in Mediterranean forests, thanks to the adaptability of their eating habits. This is the conclusion reached by an interdisciplinary study led by the Universitat Autònoma de Barcelona (UAB) and the University of Lleida (UdL), recently published in the journal Agroforestry Systems.

The research–which included the participation of Boumort Wildland, the Miranda Foundation, the Forest Horses association, and the University of Barcelona (UB)–reveals that horses adapt their diet according to breed, environment and use. This flexibility helps them play a complementary role alongside other herbivores in sustainable fire prevention strategies, given that their grazing reduces fuel loads and maintains open landscapes.

"Until now research on extensive herding and forest fire prevention has focused mainly on sheep and goats, with some isolated studies done on breeds of rustic cattle. There have been very few studies on horses within this context, since traditionally they are classified as plant grazers that have little effect on woody vegetations", explains Ariadna Nieto-Espinet, Ramón y Cajal researcher at the UdL and zooarchaeologist. "Our work is one of the first to use empirical data to analyse their potential in forest management in the Mediterannean", she adds.

The study analysed three specific cases with the aim of exploring the potential of horses in clearing forest undergrowth. At the Boumort National Game Reserve, the Przewalski’s horses live in semi-freedom in a mosaic landscape with a low herd count of 0.02 animals per hectare (ha) and year. At the Garraf Natural Park, the rustic Pottoka horses continuously grazed and also roamed in semi-freedom during one year, with a low herd demography (0.2 animals/ha/year). The third case examined crossbred horses grazing for short periods of time, with supplementary food and a high animal count (2.5 animals/ha for the duration of one and a half months).

The team analysed the horses’ diet based on 50 fresh faecal samples. "We used microhistological analysis of plant epidermis in faeces and advanced statistical models to obtain a precise assessment of the shifts in diet of these animals", specifies Araceli Gort-Esteve, researcher at the UAB and the Institute for Game and Wildlife Research (IREC-CSIC). Among the species found were woody plants of the Quercus, Juniperus and Pistacia genera, and other herbaceous species such as the Mediterranean false brome (Brachypodium retusum).

The results indicate that Przewalski's wild horses, in a mosaic landscape with patches of forest, scrub, and meadows, keep the fields cleared throughout the year by eating mainly grasses, with little impact on woody vegetation. Rustic breeds, such as the Pottoka, adapt to long periods of grazing by initially consuming fine, highly flammable grasses, and then moving on to woody plants as the grasses are depleted. They effectively manage both fine and coarse fuels, contributing to the control of the undergrowth. Finally, crossbred horses, subjected to intensive short-term grazing with supplementary feeding, quickly move from fine fuels to woody plants, demonstrating their potential for targeted management actions.

“The results with Pottoka and crossbred horses clearly show that horses, considered grazers with a preference for grasses, can quickly adapt to available resources, including woody species. This flexibility makes them a valuable resource for fire prevention strategies in Mediterranean landscapes, complementary to sheep and goats,“ says UAB lecturer Jordi Bartolomé Filella. ”Rustic breeds, often less valued today, have a great adaptive capacity that makes them key in silvopastoral tasks. Our study shows that horses can not only contribute to undergrowth control, but also to the maintenance of open spaces and mosaic landscapes," adds Ariadna Nieto-Espinet.

The research team agrees that more long-term studies are needed to quantify the direct impact of horses on reducing flammable biomass. Nevertheless, they believe that their dietary adaptability could make them a promising tool in more sustainable forest management strategies, especially in a context of climate change, rural depopulation, and increased risk of fires.