Yew(Taxus baccata L.) regeneration is facilitated by fleshy-fruited shrubs in mediterranean environments

摘要

Yew Taxus baccata is catalogued as a species endangered and prone to extinction in the Mediterranean mountains of southern Spain, due to the small size and senescent status of most populations. In this paper, we study the effects of herbivory and the protective role of woody shrubs in the regeneration ability of the yew in the Sierra Nevada. The estimated density of the yew in the study plot was 287.9 individuals/ha, more than 90% being juveniles (seedlings and saplings), which were mostly locatedunder fleshy- frulted shrubs. Saplings suffered serious herbivore damage when unprotected by shrubs. Thus, fleshy-fruited shrubs proved to be the best habitat for seedling establishment and sapling survival and growth. The abundance of fleshy-fruited shrubs in our study site provides a yew population characterized by an active regeneration under natural conditions. We suggest that the maintenance of healthy populations of yew in Mediterranean mountains is strongly dependent on the conservation of well-developed fleshy- fruit understories and their community of avian dispersers.