The conservation status of an endemic species of northern Sardinia: Centaurea horrida Badarò (Asteraceae)

When assessing the conservation status of narrow endemic plants, life history traits must be taken into account, since endemics
combine small population ranges and sizes, and long persistence with limited reproductive and dispersal ability. In this paper,
we present the global assessment of the conservation status of a narrow endemic plant from the Sardinian-Corsican
biogeographic province, by applying IUCN criteria and categories, together with an evaluation of some reproductive traits.
Centaurea horrida
Badarò (Asteraceae) is an endemic species of northern Sardinia (Italy). It is protected by the Bern
Convention (Appendix I) and listed as priority species by the “Habitat” Directive (92/43/EEC, Annex II). The species appears
in the 1997 IUCN Red List as “Vulnerable” (VU). With the aim of evaluating the risk of extinction and of providing
management tools for the network of protected areas in which this species is present, some reproductive traits have been
evaluated, and the distribution, size and structure of its population have been measured according to IUCN 2006 Guidelines.
Centaurea horrida
is not able to self-pollinate and its effective seed dispersal ability is limited. Its extent of occurrence is
172.43 km
2
and its area of occupancy is 108 km
2
. Population size has been estimated at 11,719 adult individuals. Significant
differences in adult densities among sites have been highlighted. The structure of the population is dominated by adult
individuals (on average 68%), while the proportion of seedlings is only 7% on average. Its habitat underwent an extinction
rate of 18% in 50 years. On the basis of the data gathered, the status to be assigned to
C. horrida
is that of “Endangered”
(EN). This first attempt to evaluate the conservation status of a narrow endemic plant from the Sardinian-Corsican
biogeographic province allowed us to conclude that the management of rare species must be site-specific and that there is
urgent need to acquire detailed data on endangered species, especially within biodiversity hotspots, and to continuously
update Annex II of the EU Habitat Directive and the IUCN Red List.