The Ammophila problem on the Northwest coast of North America

Abstract

In the 125 years since its introduction Ammophila arenaria (L.) Link has spread along the entire west coast of North America. This has resulted in the development of a high, wide foredune dominated exclusively by Ammophila. On the central Oregon coast there is no evidence of a foredune existing prior to the introduction of this species. Because this large foredune blocks virtually all inland movement of beach sand, it is thought that the spectacular winter transverse dunes of the central Oregon coast will rapidly deteriorate and stabilise, resulting in the loss of their scenic and recreational values. There is much evidence that the dune landscape of this coast has gone through several major cycles of stabilisation and rejuvenation since sea level reached maximum elevation after the last glaciation. Since there are several native plant species capable of building a well-developed foredune, the absence of a foredune might be explained by this local coastline history. At present the highly invasive and aggressive Ammophila has out-competed the native species and has drastically reduced their habitat. The biology of Ammophila is reviewed and the efforts to control or eradicate the species are discussed. It is suggested, for management purposes, that Ammophila will not significantly alter the natural stabilisation-rejuvenation cycles. On the other hand, native foredune plant communities will become increasingly uncommon, and efforts should be made to preserve examples of these diverse and highly specialised communities.