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Ailanthus altissima (Mill.) Swingle (“Tree of Heaven”), native to China, has become invasive all over the world. In Croatia it is present in all administrative regions, where it can form dense forest communities. Although there are several ecological studies on this species, there is a lack of floristic-vegetational data for Croatia. We present the results of a preliminary floristic- vegetational investigation on A. altissima stands along the Croatian coast and islands, based on a dataset consisting of 56 phytosociological relevés, carried out according to the Braun- Blanquet approach. In focus was the area from the island of Krk in the north, to the Prevlaka peninsula (Konavle region) in the south of the Croatian coast. Classification of the dataset was carried out by TWINSPAN, run under the JUICE software. To check the differentiation of the obtained vegetational groups Non-Metric Multidimensional Scaling (NMDS) was performed on a dissimilarity matrix of Bray–Curtis. In our study, two types of stands were defined: (i) those with stratified structure and high canopy density on the dry soils and low anthropic disturbance, and (ii) paucispecific stands with a monolayered structure typically found in agricultural and peri-urban areas with high anthropogenic disturbance. Furthermore, our results also showed the floristic and physiognomic similarity of A. altissima stands with the recently described plant associations Asparago acutifolii-Ailanthetum altissimae and Aro italici-Ailanthetum altissimae from the Italian sub-Mediterranean and Mediterranean areas. According to the current state of knowledge, the attribution of these stands to the Robinietea class seems to be the only way forward. Future studies, both in the Mediterranean and Continental regions in Croatia, will better clarify the syntaxonomic position of the A. altissima stands, as well as the syntaxonomic framework of the Robinietea class. |
