No abstract

Over the last decades, the reduction of manpower for herd management has led to an increase of continuous grazing systems (CGS) in the Italian Alps, which allow cattle to roam freely. Under CGS, due to high selectivity, livestock exploit grasslands unevenly, over-and under-using specific areas at the same time with negative effects on their conservation. To counteract these effects, a specific policy and management tool (i.e. Grazing Management Plan) has been implemented by Piedmont Region since 2010. The Grazing Management Plans are based on the implementation of rotational grazing systems (RGS), with animal stocking rate adjusted to balance it with grassland carrying capacity. A case study was conducted on alpine summer pastures to test the 5-year effects produced by the implementation of a Grazing Management Plan in grasslands formerly managed under several years of CGS on 1) the selection for different vegetation communities by cattle, 2) the abundance of oligo-, meso-, and eutrophic plant species (defined according to Landolt N indicator value), and 3) forage yield, quality, and palatability. A total of 193 vegetation surveys were carried out in 2011 and repeated in 2016. Cows were tracked yearly with Global Positioning System collars to assess their grazing selectivity, and forage Pastoral Value (PV) was computed to evaluate forage yield, quality, and palatability. Five years after RGS implementation, cow selectivity significantly decreased and the preference for the different vegetation communities was more balanced than under CGS. The abundance of meso-and eutrophic species increased, whereas oligotrophic ones decreased. Moreover, the abundance of moderately to highly palatable plant species increased, whereas non-palatable plant species decreased, with a consequent significant enhancement of the PV. Our findings indicate that the implementation of Grazing Management Plans can be considered a sustainable and effective management tool for improving pasture selection by cattle and forage quality in mountain pastures.

The study of plant phenology has frequently been used to link phenological events to various factors, such as temperature or photoperiod. In the high-alpine environment, proper timing of the phenological cycle has always been crucial to overcome harsh conditions and potential extreme events (i.e. spring frosts) but little is known about the response dynamics of the vegetation, which could shape the alpine landscape in a future of changing climate. Alpine tundra vegetation is composed by an array of species belonging to different phytosociological optima and with various survival strategies, and snowbed communities are a relevant expression of such an extreme-climate adapted flora. We set eight permanent plots with each one in a snowbed located on the Cimalegna plateau in Northwestern Italy and then we selected 10 most recurring species among our plots, all typical of the alpine tundra environment and classified in 3 different pools: snowbed specialists, grassland species and rocky debris species. For 3 years we registered the phenophases of each species during the whole growing season using an adaptation of the BBCH scale. We later focused on the three most biologically relevant phenophases, i.e., flower buds visible, full flowering, and beginning of seed dispersion. Three important season-related variables were chosen to investigate their relationship with the phenological cycle of the studied species: (i) the Day Of Year (DOY), the progressive number of days starting from the 1st of January, used as a proxy of photoperiod, (ii) Days From Snow Melt (DFSM), selected to include the relevance of the snow dynamics, and (iii) Growing Degree Days (GDD), computed as a thermal sum. Our analysis highlighted that phenological development correlated better with DFSM and GDD than with DOY. Indeed, models showed that DOY was always a worse predictor since it failed to overcome interannual variations, while DFSM and marginally GDD were better suited to predict the phenological development of most of the species, despite differences in temperature and snowmelt date among the three years. Even if the response pattern to the three variables was mainly consistent for all the species, the timing of their phenological response was different. Indeed, species such as Salix herbacea and Ranunculus glacialis were always earlier in the achievement of the phenophases, while Agrostis rupestris and Euphrasia minima developed later and the remaining species showed an intermediate behavior. However, we did not detect significant differences among the three functional pools of species.

Aim:The implementation of Grazing Management Plans (GMP), a specific policy and management tool, aimed at enhancing farm productivity while preserving plant diversity, soil and landscape. The GMP are based on rotational grazing systems (RGS) with animal stocking rate adjusted to balance grassland carrying capacity. The aim was to test the 5-year effects produced by GMP implementation on botanical composition, plant diversity and soil nutrient content on sub-alpine and alpine pastures. Location: Val Troncea Natural Park, western Italian Alps. Methods: A total of 199 vegetation transects was carried out in summer 2011 and repeated in summer 2016. The botanical composition was recorded and plant diversity indices, i.e. species richness and Shannon diversity (H′ index), were computed. Mean soil nutrient content was indirectly estimated through computation of Landolt N indicator value (N index) for each transect. Pair-sample statistical tests and PERMANOVA were perfomed at different levels: on the whole vegetation dataset, on vegetation communities (i.e. vegetation types and ecological groups) and considering functional pools of species. Results: Considering the whole vegetation dataset, species richness, H′ index and N index significantly increased from 2011 to 2016. Moreover, species richness significantly increased in almost all vegetation ecological groups, with the highest increase within the mesotrophic group. The H′ index significantly increased in eutrophic, preforest and thermic groups, while the N index increased in all vegetation groups, except in the eutrophic and snow-bed groups. A significant difference in botanical composition was detected within oligotrophic, mesotrophic and thermic groups. The number and cover of N-poor high-elevation species increased in all groups and this result might be related to effects produced by livestock, which promoted seed transport and increased connectivity amongst different communities. The meso-eutrophic species number and cover significantly increased within thermic, mesotrophic and pre-forest groups, suggesting greater use of such areas by livestock under RGS than under continuous grazing. Conclusions:The implementation of RGS with stocking rate adjustments proved to be an effective and a sustainable management tool to enhance botanical composition and plant diversity of sub-alpine and alpine grasslands over a 5-year span. | Applied Vegetation SciencePEROTTI ET al.