First record of the steppic relict Astragalus exscapus L. subsp exscapus in the Apennines (Abruzzo, Italy), and biogeographic implications

Abstract

Astragalus exscapus L. subsp. exscapus (Fabaceae) is a rare and declining perennial herb with a very fragmented distribution range. It is interpreted as a relict of the glacial steppe flora. In Italy, it was known until now only from the Alpine “dry valleys”, namely from Val d’Aosta and Val Venosta/Vinschgau. We report on the discovery of a population on the slopes of the Fucino basin in the Central Apennines (Abruzzo, Italy). The finding significantly expands the known species range (the site is > 600 km away from the nearest known populations), suggesting that during Pleistocene steppic phases it had a wide distribution across Europe. A. exscapus adds to a number of other steppic relicts found in the Fucino basin, highlighting that some inner valleys of the Central Apennines, featuring a relatively continental climate, perform as “interglacial refugia″ for the steppe flora. Further research is needed to ascertain the species’ local distribution and abundance, and to clarify its vicariance history; however, the finding underlines the need to re-evaluate priorities in landscape management, as in the Apennines dry grasslands are often given low values compared to forests and are frequently destroyed by afforestation practices with non-native conifers.