The impact of human trampling on a threatened coastal Mediterranean plant: the case of Anchusa littorea Moris (Boraginaceae)

In a 5-period study (2007-2011) we examined the effects of human trampling on the last remaining population of Anchusa littorea on the sandy coastal habitat. This species, considered extinct in the wild for several years, was casually rediscovered in a small population at Is Arenas (SW Sardinia). We monthly monitored six trampled and six untrampled permanent plots, mapping individuals and recording their size and reproductive variables. Trampled and untrampled plots showed significant differences with respect to plant density, plant size and reproductive performance (flowers and fruits production). This study demonstrated that human trampling represents a severe threat to the conservation of A. littorea and urgent measures should be planned to protect the unique remnant population in the dune system of Is Arenas. Tourist flow should be redirected and confined to others areas in order to promote the natural expansion of A. littorea in its original habitat. A possible integrated strategy for the conservation and management of the species consists of combining in situ and ex situ measures.