Plant community, ecology and CSR functional strategy of Linaria tonzigii Lona, a steno-endemic species of the Italian pre-Alps

Linaria tonzigiii is a rare steno-endemic species of Community interest that grows on some limestone screes in the Orobie Bergamasche Regional Park (Italian Alps). Currently, its presence is certain in just a few sites of the Orobic pre-Alps many of which were refuge zones during the glaciations of the Quaternary Age. Information is scarce regarding its ecology (and especially synecology) and its Grime's CSR functional strategy. For this reason, this study, as well as analyzing the floristic composition and ecology of the Linaria tonzigiicommunity by means of traditional methods (ecological indices), also evaluated the Grime's CSR strategy of this endemic species using the latest methods and tools. Analysis of 24 phytosociological relevés conducted in five different areas revealed that this species constitutes a single plant community consisting of basophile species mostly typical of limestone screes. The analysis of the CSR strategy revealed that the mean strategy of Linaria tonzigii is R/CSR although the species presents slightly different strategies in the different sampling areas. This research suggests that the functional variability of the species is much wider than is currently known. The analysis of plant height of Linaria tonzigiialso showed that the population isolated at the northern limit of the distribution range of the species has significantly taller and less stress-tolerant individuals than those in other areas, suggesting that it may be a different ecotype. This study aims to stimulate researchers to study the little-known endemic species in order to protect and valorize the biodiversity of the planet.