Grazing management for land conservation and restoration in the xerothermic oases

The present contribution shows the results of the project LIFE12 NAT/IT/000818 XERO-GRAZING. Sheep grazing management was implemented in abandoned dry grasslands of the Susa Valley as a conservation tool for the maintenance of the threatened habitats 6210(*) and 6240*. 114 permanent transects were positioned in the pasture and vegetation surveys were carried out each year from 2014 to 2018. Biodiversity indexes did not change, while species composition in grazed transects modified towards an increase of pioneer xerothermic species (i.e. short-living species of Koelerio-Corynephoretea e Thero-Brachypodietea classes that include Mediterranean species of high conservation interest). These species spread in litter-free bare ground gaps created by animal trampling through the opening of the litter layer, especially in penning areas where a high stocking density was applied. In late 2017 an accidental wildfire occurred, burning all of the permanent transects. One year after the wildfire, pioneer xerothermic species strongly increased due to the further opening of the litter layer. Ruderal species were favored by the wildfire too and Shannon diversity index increased in burned transects. In conclusion, our results show that sheep grazing management represent an effective tool for the enhancement of the species composition and target flora of the habitats 6210(*) and 6240*. The wildfire caused a modification of the species composition in the first year after the event, but any adverse effect on biodiversity was observed.