Using mechanical clearing and goat grazing for restoring understorey plant diversity of embankments in the Rhône valley (Southern France)

Abstract

Consumption by animals remains one of the key points to assess the effectiveness of grazing impacts in woodland for increasing understorey plant diversity. To limit the spread of the brambles and restore understorey plant diversity on an artificial embankment an original system of clearings connected by paths was created by mechanically crushing brambles and allowing them to be grazed by rustic goats. The analysis of the indices of consumption of bramble under GIS has been used to provide an estimation of the volume ingested and an estimation of the effectiveness of the goats. The impacts of three different managements (goat grazing, brush clearing and grazing, clearing and exclusion of grazing) and control without management were then tested during a three-year period. The monitoring of the vegetation on permanent plots provided evidence that goat grazing significantly increased in the short term the species-richness and heterogeneity of herbaceous plants communities, in complement with prior clearing. Thus, the objectives of the managers to open up the area and reduce the bramble cover were achieved, but the prior introduction of goats and the installation of mobile enclosures would be advisable in order to ensure the sustainability of these measures on plant diversity in the long term.

Keywords:

• Bramble
• eco-grazing
• mechanical mowing
• Rubus ulmifolius gr. Schott

Acknowledgements

We thank SFR Tersys for the prize awarded in 2014. Our thanks are due to Bruna Romanini for the construction of the exclosures at the site, Romain Brusson (CNR) and Denis Roux (ONCFS) for access to the site. We warmly acknowledge the technical assistance received from Jean-François Alignan, Anne Aurière, Jordan Batikh, Olivier Blight, Julie Chenot, Anouk Courtial, Marthe Lucas, Daniel Pavon, Arthur Rocher and Christel Vidaller, for the botanical inventories and estimations of the goat consumption rate. We thank the two anonymous reviewers for their useful comments.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

We thank the Compagnie Nationale du Rhône (CNR), the owner of the site and the Office National de la Chasse et de la Faune Sauvage (ONCFS), the manager of the site, for their financial support.