Shrubland increases in the Alps. One of the main objectives of the Pasto project was to assess the possibilities of limiting reforestation by means of suckler cows in the subalpine zone. Our work aims at clarifying the herd-vegetation relationship, both to ensure good grazing management and to understand the dynamics of reforestation.
Most of the observations in this article were carried out on a pasture of 2.9 ha located on a northern slope at an altitude of about 1800 masl. GPS monitoring of cattle showed that the animals roamed all areas of the plot, even the most closed ones. Vegetation types known to be of low forage value (like tall herb community) were heavily visited by cows in early season. The analysis of forage consumed by livestock indicates that animals selection is important: the nutritive value remains relatively constant throughout the season. Botanical observations show that the most eaten herbaceous plants are not necessarily those known to be the most palatable. Among woody species, cattle browse willingly young green branches of alder. As long as these plants don't exceed 1.5 m in height, a grazing intensity of 80 LU·days/ha is sufficient to prevent their expansion.