Authors: Ribeiro, Inês; Líbano Monteiro, Marta;Themudo Barata, Leonor;Gama, Ivo;Rodrigues, Nuno;Domingos, Tiago;Proença, Vânia;

The abandonment of marginal farmland across the Mediterranean is leading to an increase in shrub encroachment, which may result in habitat homogenization and increased wildfire risk. This study investigated the performance of different grazing regimes in regulating fire prone vegetation, supporting biodiversity conservation, and to identify and deliver cost-effective solutions for ecosystem management. Specifically, three grazing regimes (extensive cattle grazing, semi-wild horse grazing, and no grazing) were assessed at three case-study sites in Portugal. Overall, non-grazed sites showed higher shrub connectivity at the landscape level, had a more complex vertical structure and larger proportion of tall grasses, which increases the risk of wildfire. Semi-wild grazing showed positive but limited contribution to wildfire prevention, which may require additional management measures, while extensive grazing (with additional feeding) created vertical fuel discontinuity, reduced fuel loads, and supported high species richness, showing, on the other hand, impact in tree recruitment and suggesting the need for protective measures. The performance and suitability of grazing regimes, and their combination, will also depend on local environmental conditions and management goals. Ultimately, where wild herbivores’ density is low, semi wild and/or domestic herbivores in extensive regimes can help regulate fuel loads and maintain habitat diversity.