Fir expansion not controlled by moderate densities of large herbivores: a Mediterranean mountain grassland conservation issue
Résumé
Context Forest expansion following the cessation of grazing is a threat to biodiversity in mountain grasslands that are compo- nents of Mediterranean cultural landscapes. & Aims We hypothesised that ungulates could mitigate tree recruitment, thus conserving mountain grasslands. We tested the efficiency of grazing and browsing by domestic and wild ungulates (sheep, roe and red deer) at inhibiting silver fir (Abies alba Mill.) encroachment in a conservation area, one of the main browsed trees.
Methods The fir trees’ age structure was analysed by dendrochronology, and the individual growth patterns and scars were recorded in their tree-ring series. & Results Fir density has increased since the 1960s, simultaneously with the increase in ungulate populations. The scar occur- rences only appeared during the 1970s. Most scars were observed on seedlings and small saplings. The impacts of ungulates are observed on the radial and height growth of trees, mostly on trees < 100 cm, but it did not however result in controlling the recruitment of fir.
Conclusion The hypothesis that a moderate density of ungulates might inhibit tree encroachment is therefore rejected, even in the case of a highly palatable species such as silver fir. Ungulates, solely, would not be an appropriate policy for grassland conservation in Mediterranean mountains.
Fichier principal
Chauchard et al Annals of Forest Science 2018.pdf (61.19 Mo)
Télécharger le fichier
Origine | Fichiers produits par l'(les) auteur(s) |
---|