Population decrease of Thymelaea hirsuta (L.) Endl. in Liguria: conservation problems for the North Tyrrhenian sea.

This study focuses on the decrease of T. hirsuta populations along the North Tyrrhenian Coast, the northern edge of the species areal; and on the necessity to preserve this species within this area. The drastic drop in population density is prejudicing the survival of this species along the North Tyrrhenian Coast, which features high mortality rates among adult plants and seedlings. In the Ligurian station of Bergeggi, a drop in population was noticed after 3 years of observation, with an average of 49.18%. At the end of the study period all specimens appeared to have a smaller number of branches while the total volume of plants dropped by 71.91%. Fruit production varied seasonally, though in general low rates of ripe fruit and fruit germinability (0.28%) were recorded. Ex situ seeds also showed low rates of germination. Reproduction by cuttings yielded very poor results and in vitro micropropagation was unsuccessful. In defining possible conservation strategies for the future of the plant in this area, sexual breeding was found to be the only way to regenerate the natural population, while vegetative reproduction seemed to be difficult to implement.