Plant taxa and communities on three islets in south Croatia, NE Mediterranean.
The flora and vegetation of three small islets with surface areas from 1.04 to 3.31 hectares, lying between the mainland and the Pelješac peninsula in south Croatia, were investigated in 2014 and 2015. The floristic data have been used to analyze life-form and chorological spectra and to assess species area relationship, the occurrence of islet specialists and to assess the risk of alien plants invasion. Altogether, 126 vascular plant taxa (species and infraspecific units) were recorded on all the islets combined. The richest islet is Gospin Škoj with 72 taxa, followed by Srednjak (68) and Goljak (48). A total of five plant associations, one subassociation and two stands within five vegetation classes have been identified on the islets. Benthic cormophyte communities in the eulittoral and infralittoral zones are represented by Posidonietum oceanicae, Cymodocetum nodosae and Nanozosteretum noltii. The halophytic vegetation of the coastal rocks belongs to the proposed new subassociation Limonietum anfracti helichrysetosum italici. Shrubland vegetation was composed of the Myrto communis-Pistacietum lentisci and Oleo sylvestris-Pistacietum lentisci associations, macchia with Erica arborea and the Olea sylvestris-Narcissus tazetta community. Clear signs of the degradation of the macchia, due to the high anthropogenic influence, particularly the presence of European rabbit populations. have been observed.