Compatibility of regeneration silviculture and wild ungulates in a Mediterranean pine forest: implications for tree recruitment and woody plant diversity

Abstract

Key message: Small-scale forest interventions (< 0.75 ha) promoted advanced regeneration and woody plant beta-diversity without increasing ungulate habitat use and detrimental browsing damage. Rubbing damage by ungulates was higher in the treated areas and no effect was found on woody plant alpha-diversity. Context: Adapted silviculture is needed to promote forest persistence and plant diversity in the current context of wild ungulate overabundance. Aims: This study examines the ungulate effects on tree recruitment and woody plant diversity after silviculture treatments (small-scale regeneration fellings on Pinus species). Methods: We compared tree recruitment, browsing/rubbing damage, and woody plant diversity on 17 pairs of control/treated areas in an ungulate-dominated Pinus halepensis forest. Results: Recruitment levels were significantly higher in the treated areas as compared to intact (control) plots only for large saplings and juveniles (> 130-cm high). Ungulates did not use the treated areas more often than the control plots but caused significantly greater rubbing damage in the treated areas. Silvicultural treatments did not have a significant effect on alpha woody plant diversity but did promote beta-diversity, with a 49.7% woody species turnover. We did not find any clear patterns indicating that the treated areas suffered heavier browsing damage across all woody plant species. Conclusion: This study highlights that small-scale forest interventions (< 0.75 ha) are small enough to avoid greater habitat use and browsing damage by ungulates but sufficiently large to promote advanced regeneration (large saplings and juveniles), with the additional benefit of increasing woody plant heterogeneity and structural diversity.