Burning season and scrub type determine Mediterranean shrubland responses to pyric herbivory

Livestock grazing historically shaped Mediterranean shrublands by maintaining open habitats and diverse plant communities. Rural abandonment has reversed this process, resulting in fuel accumulation, and increased forest connectivity and wildfire risk. Pyric herbivory, combining prescribed burning and grazing, can mitigate these threats by reducing fuel loads, controlling woody encroachment, and restoring ecosystems processes. Despite its potential, pyric herbivory remains understudied in semiarid Mediterranean shrublands, where its drought-adapted plant phenology, life‐history traits, and composition may produce season- and vegetation-dependent outcomes. We conducted a two-year field experiment applying spring and autumn moderate-high intensity prescribed burns, with and without low intensity grazing by sheep and goats, across four vegetation types: low- and medium-cover areas, and dense areas dominated by Genista scorpius or Macrochloa tenacissima. Both prescribed burning and pyric herbivory reduced fuel loads while preserving forage quality, but only combined fire and grazing significantly increased plant diversity. In Macrochloa sites, spring burns during active growth favored rapid Macrochloa clonal recovery and competitive dominance, limiting diversity, whereas autumn burns during plant dormancy reduced Macrochloa vigor, enabling diverse herbaceous establishment under grazing. In Genista sites, irrespective of burning season, its lignotuber resprouting and seed-bank recruitment allowed cover recovery, albeit slower, favoring an increase in diversity maximized when burns were followed by grazing. These findings underscore the need for vegetation- and season-specific fire-grazing regimes that align with plant phenology, growth forms, and life strategies. Undoubtedly, pyric herbivory emerges as an adaptable strategy to mitigate wildfire risk, maintain pastoral value, and enhance biodiversity in fire-prone Mediterranean landscapes.