Hay Transfer Promotes Establishment of Mediterranean Steppe Vegetation on Soil Disturbed by Pipeline Construction

Abstract

The Coussouls de Crau Nature Reserve is a xeric steppe providing a habitat for remarkable animals. Over the past centuries, this steppe has been partly destroyed and fragmented and has been reduced to 9,500 ha out of the 55,000 ha existing before the 16th century. Although this ecosystem is protected, 23 ha of natural habitat were nonetheless destroyed in 2006 during the construction of an underground pipeline. To mitigate potential future damage, an original experiment in restoration ecology was adapted and tested: the technique of hay transfer. The objective of this experiment was to find ways of accelerating steppe vegetation colonization on the soil over the buried pipelines by the reintroduction of steppe species. A factorial experiment was set up to test the effects of habitat characteristics, grazing, and hay transfer. The results obtained for 3 years after the experimentation setup are conclusive in favor of using hay transfer for the restoration of Mediterranean steppe ecosystem. Hay transfer has significantly increased the species richness on restored areas and has allowed the reintroduction of some typical steppe species. Among these species, we found a wide variety of annual grasses which play a key role in the recovery of steppe vegetation and provide food for sheep flocks. Sheep herding must be maintained during the ecological restoration of the herbaceous steppe community, because grazing significantly increases species richness on restored areas without changing species assemblies.