RISORSE GENETICHE DI PIOPPO NERO IN ITALIA

European Black Poplar (Populus nigra L.) is one of the most representative species of ancient european floodplain forests. It is a pioneer species that colonizes bare sediments abandoned by floods. When Populus nigra stands grow old they do not regenerate and are substituted by definitive species. During their lifespan P. nigra plants produce high quantities of seeds which colonize new sites. Thus P. nigra forms metapopulations including several stands of different ages which are continuously turned over. The life cycle of this species is totally adapted to river dynamics and totally reliant on them. The species is part of a rich ecosystem (alluvial forests) and hosts a high quantity of arthropod and avian fauna. In the few last decades deep alterations of riparian ecosystems due to agriculture and urbanization have led to a strong reduction in original black poplar populations; river management has compromised their regeneration while extensive cultivation of hybrid poplars has caused genetic erosion. Today the species is rare and threatened with extinction in most western European countries. This paper briefly describes the species' state and the initiatives taken for its conservation. After briefly summarizing leading European initiatives (EUFORGEN), it focuses on Italy and particularly on Piedmont. Here, the previous Poplar Sperimentation Institute keeps wide ex situ collections of authocthonous poplars and has carried on studies on remaining wild stands of P. nigra and P. alba still present in the Piedmont region. Using authochtonous propagative material of certain origin kept in its vegetal collections and nurseries the Institute has realized together with the Po and Orba rivers Fluvial Park a series of artificial stands of black poplar along the Po river in central-eastern areas of the Region, starting the buildup of an in situ Genetic Conservation Units network. The Po river still has river dynamics that enable black poplar regeneration, but there is a lack of adult trees in the environment. The aim of these artificial plantations is to start a dynamic conservation that allows the species evolution and adaptation to environmental and climatic changes, in order to guarantee the species survival in the long-term. Populus nigra plantations have been realized within river restoration activities to increase quality and functions of the riparian ecosystem.