Naufraga balearica , a threatened narrow endemism of the B alearic I slands (western M editerranean basin): assessing the population dynamics of two subpopulations

Naufraga balearica constitutes a monospecific genus of M ajorca ( B alearic I slands) and is Critically Endangered according to I nternational U nion for C onservation of N ature categories. The species has a narrow distributional area, with one subpopulation at C oves B lanques ( CB ) and a small set of subpopulations on the F ormentor P eninsula. A previous work has shown that the subpopulation in C ap de C atalunya ( CC ) (located on the F ormentor P eninsula) has undergone a distinct decline over the last decade. Herein, we report a comparative study of the population dynamics of N. balearica at the CB and CC sites. By monitoring permanent plots for 6 years (2004–2009), we analyzed the frequency of cells in which the species was present, and, for each annual transition (from N ovember, year t to N ovember, year t  + 1), we determined the frequency of cells in which the species was stable, decreased or increased for each species and site using a G ‐test of independence. The same parameters were also analyzed for N. balearica at the quarterly transitions of N ovember– F ebruary, F ebruary– M ay, M ay– A ugust and A ugust– N ovember. The results indicated that the decline of the threatened species was more marked in the CB subpopulation. N .  balearica showed a seasonal trend at both sites, with some exceptions. The most common neighboring species were Dactylis glomerata and Erodium reichardii , and they negatively affected N. balearica ; however, the neighboring species effect was not homogeneous among the annual transitions analyzed, indicating that other factors are involved. Finally, some conservation measures are proposed.