Caractérisation, par des indices botaniques, des pratiques de gestion des prairies de deux terroirs des montagnes de Bigorre

Using macrophyte indices to characterise pasture management practices in 2 rural areas in the Bigorre mountains

Three analytical tools were used to examine changes in pastures located in different rural areas in the Central Pyrenees. The results obtained were analysed in tandem with data on environmental parameters (e.g., climate, soil properties, and forage composition) and information obtained from surveys conducted with farmers. We were thus able to determine how well these indices revealed differences attributable to area characteristics, pasture management practices, and their changes over time. The Ellenberg N index differed among areas (i.e., as a result of differences in altitude and soil acidity) but could not explain differences in production. The Balent indices and a functional analysis of grass species (as per Cruz and Duru) revealed that, although high altitude areas were increasingly exploited between 2002 and 2012, such land nonetheless remains the least productive. Rapid plant censusing techniques can be used to obtain the data necessary to calculate these macrophyte indices, which yield quality agroecological information on the relationship between ecosystem services and pasture management practices at the field level.