A contribution to the knowledge of Linaria tonzigii Lona, a steno-endemic species of the Orobie Bergamasche Regional Park (Italian Alps)

Linaria tonzigii is a rare steno-endemic species of Community interest that grows on some limestone screes in the Orobie Bergamasche Regional Park (Italian Alps). In- formation is scarce regarding its ecology (and especially synecology) and its Grime’s CSR functional strategy. For this reason, this research, as well as analysing the floristic composition and ecology of the L. tonzigii community by means of traditional methods, also evaluated the Grime’s CSR strategy of this endemic species using the latest methods and tools. Analysis of the phytosociological relevés conducted in five different areas revealed that the species constitutes a single plant community (the Linaria tonzigii-Hornungia alpina community) consisting of basophile and xerophile species mostly typical of limestone screes. The analysis of the CSR strategy revealed that the mean strategy of L. tonzigii is R / CSR, although the species presents slightly different strategies in the different sampling areas. This article reports the first ever data regarding inter-population variation in plant functional strategies in nature and suggests that the functional variability of the species is much wider than had been thought. The analysis of plant height of L. tonzigii also showed that the population isolated at the northern limit of the species’ distribution range has significantly taller and less stress-tolerant individuals than those in other areas, suggesting that it may be a different ecotype. This article aims to stimulate researchers to study little-known endemic species in order to protect and valorize the biodiversity of protected areas.