Phytocoenological approach to the ecology of Laurus nobilis L. in Italy.

Laurus nobilis L. (Laurel) is considered one of the most emblematic epigones of the late-Tertiary laurophyllous biome, persisting within the Mediterranean vegetation. Describing its present ecology and coenology is crucial to understand its biogeographical history as well as to develop consistent conservation and management practices in the context of the European Habitat Directive. We used recently available vegetation and environmental databases to investigate the coenological amplitude of Laurus in Italy, and to elucidate significant aspects of its persistence in the country. The coenological amplitude was assessed using the clustering method. Ordination techniques and regression trees were used to understand which environmental factors influence, respectively, the occurrence and the abundance of the species and, therefore, characterize its niche. Our results show a wide coenological amplitude of Laurus with respect to other laurophyllous species, growing within a wide range of forest communities. While the occurrence of the species is limited by winter temperature and favored by precipitation seasonality, changes in its abundance show a more refined pattern. In this latter case, two main groups of Laurus populations were differentiated based on water availability. The first group depends on abundant precipitations during the year while the second one buffers the summer aridity with soils rich in nutrients and moisture. Our findings provide crucial knowledge on Laurus habitats in Italy. However, discrepancies between our results and guidelines of the European Habitat Directive arose. The results presented here allow scientifically sound procedures for the regional conservation and management program. [ABSTRACT FROM AUTHOR]