Grazing land management and biodiversity in the Atlantic European heathlands: a review

摘要

Atlantic heaths are semi-natural habitats of high biodiversity interest which once covered large areas of the Atlantic Region. Nowadays these heathlands are dramatically reduced in many countries although they still cover wide areas in the north-west Iberian Peninsula, especially in the poorest and most socially marginal areas that are frequently affected by wildfires. We review the role of livestock grazing as a sustainable management strategy for heathlands in Europe. We have worked on a generalized conceptual framework for the management of a resource of nutritional and environmental value by drawing together evidence from studies of the livestock and the community ecology of grazed plants and the associated fauna. Key factors that influence grazing impact, such as type of livestock (animal species and breed) and their management are discussed. Goats thrive better than sheep, and horses than cattle, when heathland vegetation is the predominant resource available. Regardless of the type of livestock species managed, the low nutritive value of this vegetation hinders the maintenance of productive groups of suckler dams with offspring through the grazing season. The nutritional requirements of livestock can be met by adding improved pasture areas to heathlands. Under that strategy, sheep have the best productive performance and cattle the poorest. Management of mixed flocks with goats can lead to a more efficient use of vegetation, improve productivity and develop a patchier habitat which supports a richer associated fauna. Overall the results indicate that the sustainability of livestock grazing in these marginal lands will be achieved if they are managed effectively according to the available vegetation and their effects on the biodiversity.