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.

Keywords:

• conservation
• dry valleys
• flora
• Fucino
• grasslands
• Marsica
• phytogeography

Acknowledgements

We are very grateful to D. Bouvet and A. Selvaggi for providing unpublished remarks on A. exscapus distribution records, and to L. Hermanin and B. Velettacci for valuable information on the afforestation works.