The most obvious dune scrub species in Wales is sea buckthorn (Hippophae rhamnoides), which is widely believed to be a non-native species on west coast UK dune systems. Sea buckthorn was deliberately introduced to Welsh dune systems to help stabilise the mobile dunes. Now, after a 100 year period of dune stabilisation, sea buckthorn can be a major problem species on dune systems, forming large single species stands and being very difficult to control. It produces copious berry crops that are dispersed by winter thrushes, both within dune systems and between them.