Effects of habitat structure on functional diversity of epiphytic lichen communities of coastal dunes with Juniperus spp.

Dunal ecosystems are among the most threatened habitats by human activities, which cause their fragmentation, and loss of species and functional diversity. If the effects on biodiversity loss are well known, the consequences of decreasing functional diversity are still poorly explored, but are expected to drastically affect ecosystem productivity and vulnerability. This latter is particularly evident for sensitive organisms, such as epiphytic lichens, that are symbiotic organisms representing ecologically significant component of Juniperus shrublands of coastal dune. In this work, we selected a dunal system with Juniperus shrublands, located between Marina di Bibbona and Marina di Castagneto Carducci (Tuscany – Central Italy). We aimed i) to investigate whether the habitat structure affects the functional diversity and species richness of lichen communities and ii) the presence of a model species of this habitat, the fruticose lichen Seirophora villosa. By means of a Strip Adaptive Cluster Sampling (SACS), we sampled epiphytic lichens in randomly selected plots. We used UAV photogrammetric data to obtain information on the habitat structure and we performed Linear Mixed Models (LMM) to detect the relationship between S. villosa occurrence, functional richness and habitat structure. Both functional richness and species richness significantly depended on the habitat structure. On the contrary, the presence of S.villosa was not directly related to the habitat structure, suggesting a major role of dispersal and establishment capability on its current distribution. In a future perspective, the conservation of the structure and continuity of Juniperus stand will be crucial for preserving lichen and functional diversity.