Population structure of Laurus nobilis L. in Central Italian forests: evidence for its ongoing expansion

Abstract

During the last decades, an ongoing spread of broad-leaved evergreen laurophyllous species has been reported for forests of Southern Europe. Several factors were suggested as the main drivers of the phenomenon, namely global warming, land-use change, evolutionary history, and increase in atmospheric CO2. Among laurophylls, Laurus nobilis L. is considered one of the most prominent from the morphological, evolutionary, and ecological point of view. We studied the population structure of L. nobilis in Central Italy in its natural habitat to investigate its regeneration and potential expansion along with the influence biotic and abiotic factors. To define types of population structures, we collected proportions of six growth classes of L. nobilis in 16 sites. We obtained three types of population structure, i.e., (1) stable, (2) dynamic, and (3) regressive. The first two types are the most frequent, suggesting a potential increase of L. nobilis abundance within forests of Central Italy. The regressive population type occurs mainly in sites with heavy ungulate impact. High propagule pressure along with shaded and moist environmental conditions favor L. nobilis regeneration. Accordingly, we found evidence of a recent L. nobilis spread in Central Italian forests. We suggest the increase of forest cover and age, due to the abandonment of traditional rural practices, as key factors for the regeneration of this apparently late-successional laurophyll. In conclusion, the recent expansion of L. nobilis that we observed in the Italian forest stands can therefore be ascribed to a process of natural recover of a potential niche following land-use change.

The alien Chinese windmill palm (Trachycarpus fortunei) impacts forest vegetation and regeneration on the southern slope of the European Alps

“…This biome shift is further promoted by the changing climate regime that increasingly provides more favorable conditions for laurophyllous species, potentially making the future spread of evergreen plants such as T. fortunei inevitable (Boonman et al, 2022;Elsen et al, 2022). A similar climate regime prevailed during the late Cenozoic, during which evergreen laurophyllous species dominated in southern Europe (Alessi et al, 2021), including several palm species (Gregor, 1980), but these "native" species have since gone extinct during the glacial cycles of the late Quaternary. For evergreen laurophyllous species, the Insubrian region would thus have to depend on influx of species from climatically similar regions in, for example, Asia, that is, a dynamic that would be strongly facilitated by anthropogenic introductions.…”

Nutraceutical Aspects of Selected Wild Edible Plants of the Italian Central Apennines

“…In Italy, it grows spontaneously in the central and southern areas along the coast, while in the northern regions it is cultivated. [82,83] Satureja montana L. is an herbaceous species which grows to 50 cm. The stems are woody at the base, tetragonal, erect, and have short back hairs when pubescent.…”