Managing Resources by Grazing in Grasslands Dominated by Dominant Shrub Species

The European natural grasslands are attracting new attention because of their environmental value as habitats for threatened fauna and flora species and their contribution to the diversity of landscapes. Those responsible for the implementation of the European agri-environmental policy are hence encouraging livestock farmers to adopt grazing practices that contribute to the conservation of grassland biodiversity especially by limiting encroachment by dominant shrubs. However, current scientific knowledge and technical information are often insufficient to connect flock feeding and the impact of grazing on shrub dynamics and livestock farmers are not very enthusiastic about restoring or conserving “plant mosaics” including shrubs that support biodiversity in their fields. This paper presents results of an interdisciplinary study on interactions between small ruminant feeding strategy and population dynamics of dominant shrub species with the objective of managing by grazing the structure of plant community and thus to provide the renewal of resources on a multi-year scale

Caracterización de la ingestión por observación directa en rebaños ovinos del sureste de Francia

International audienceWhen ruminants graze on heterogeneous vegetation, direct observation of bites is one of the most fitted method to estimate intake. Nevertheless its implementation in herds of more than 500 individuals has been scarce. In our study, this method was implemented to characterize the intake and know the feeding value offered by steppe vegetation. We observed two ovine flocks of 1100 and 1200 animals guided by shepherds in farm conditions. The animals used were Merinos d'Arles a breed with marked regariousness. They constitute transhumant flocks that every spring graze the steppe vegetation of the Nature Reserve Coussouls de Crau located in Southeast France. The period of adaptation was brief lasting from 7 to 22 days. In this environment composed of a unique herbaceous layer, the intake rate was 5.9 ± 2.4 g DM/min, which is similar to levels reported in woody or shrubby rangelands. We found that in this steppe vegetation sheep are capable of flows up to 13 g DM/min. In previous studies the Brachypodium retusum has been considered of low nutritional value and little appreciated by the sheep. In our case it was found that the sheep eat a wide variety of plants. But when Brachypodium retusum contributes to the majority of dry matter intake, intake rate is significantly greater (6.8 g DM/ min) than when this is contributed by forbs (4.4 g DM/min) or by the other grasses (5.8 g DM/min). This plant is revalued, our results showed that it allows sheep to make bites of mass higher than forbs and other grasses which explains its improved efficiency of collection. Direct observation allowed us to characterize the intake of sheep in Crau steppe and we consider this type of vegetation as a food source similar to woody or shrubby rangelands

Friches et broussailles : elles peuvent contribuer à la qualité environnementale et pastorale de l'espace rural

National audienc

Faire pâturer des sites naturels

ConférenceNational audienc

Pâturage et biodiversité. Où les troupeaux ne sont pas des machines comme les autres

* INRA, Centre d'Avignon, Documentation, Domaine St Paul, Site Agroparc, 84914 Avignon cedex 9 Diffusion du document : INRA, Centre d'Avignon, Documentation, Domaine St Paul, Site Agroparc, 84914 Avignon cedex 9National audienc