The natural reserve of the Marais de Lavours (460 hectares), lying between the lake of Bourget and the Rhône, plays an important role in regulating water flow. It is also the site of a various rare animal species. In the past, this area was integrated into the local economy (haymaling, digging of peat), but progresively this marsh has been abandoned and then spoilt by improvement works to the Rhône. Such change has resulted in the area becoming more isolated and uniform in character. To maintain the diversity necessary to allow the survival of the area's different species, the managers of the Reserve has introduced on an experimental basis Highland cattle and horses from the Camargue. The animals appear to have acclimatised to the area with relatively little help, and their action on the environment corresponds withe expectations of the Reserv's managers. Nevertheless, longer terms problems of the "natural" management of this situation remain.