Transplanting native woody legumes: a suitable option for the revegetation of coastal dunes

Abstract

Acacia longifolia is an invasive woody legume in many coastal sand dunes ecosystems around the world. A useful option to aid in the restoration of invaded areas after acacia removal is the revegetation of the newly open areas using appropriate native dune plants. A field experiment was performed to determine whether two shrubby legumes native to European Atlantic coastal dunes, Cytisus grandiflorus (Brot.) DC. and Ulex europaeus europaeus subsp. latebracteatus (Mariz) Rothm., are suitable to revegetate areas formerly invaded by A. longifolia. Plants of both species were grown for 5 months in a greenhouse and subsequently transplanted to three sites in a coastal dune ecosystem. We monitored survival and growth during 21 months. The effect of soil fertility at the nursery and of root nodulation on the performance of these species in the field was also analyzed. Soil fertility and nodulation had a significant effect on plant growth at the nursery, but only the symbiosis with root nodulating bacteria had a significant positive effect on the survival of both native legumes in the field and on final plant height of U. europaeus plants. We conclude that (1) both native legumes can successfully establish on sites where A. longifolia has been previously removed, thus providing a suitable tool to help in the restoration of invaded areas, and (2) the symbiosis with root nodulating bacteria is crucial for plant performance in the field.