Strategic Placement of Salt Supplements to Restore Shrub-Encroached Pastures. A Case Study from Italian Alps

Socio-economic transformations occurred in Europe over the last decades led to a broad abandonment of mountain areas. Consequently, the processes of natural succession favored shrub and tree encroachment, resulting in a dramatic degradation of semi-natural grasslands. Grazing by hardy breed cattle can be a sustainable tool to counteract these processes and restore semi-natural grasslands. In this context, the AGER iGRAL project planned to assess the effectiveness of cattle management of hardy breeds for the restoration of abandoned pastures in Alpine and Mediterranean environments. The present contribution shows the preliminary results of the strategic placement of attractive salt supplements to increase the frequentation of shrub-encroached areas by livestock. The impacts of trampling and grazing on vegetation structure were evaluated in a 24-hectare pasture (Vogna Valley, North-western Italian Alps), grazed by 72 Livestock Units of Highland cattle from 18 to 26 July 2019. Three salt blocks were placed within shrub-encroached sites and offered ad libitum throughout the grazing period. Each salt site was paired with a control one with similar topographic and vegetation characteristics. To detect the impact on vegetation structure, shrub and herbage heights were measured within a 15-m radius around each site, before and after grazing. The results show that the reduction of both shrub and herbage heights was significantly higher around salt compared to control sites (P < 0.001). This effect was less pronounced with increasing distance from the salt blocks. These promising results support the use of salt blocks for an effective grazing management of Highland cattle in alpine shrub-encroached pastures.