Zelkova sicula Di Pasquale, Garfì et Quézel is a very rare endemic species, exclusive from Sicily. It is a relic of the Tertiary flora and belongs to a genus which became extinct in the whole continental Europe during the Quaternary glacial age. At present the species consists of only 2 populations in the whole world, whose area is less than 6000 and 8000 m² large, respectively. The species is included in the IUCN Red List as “Critically Endangered” of extinction and selected among the “Top 50 Mediterranean Island Plants” at the brink of extinction, but no legal protection measure has till now been adopted.

Several investigations showed that the current habitat of Z. sicula is somewhat far away from a bioclimatic optimum and the most recent trends in climate change certainly give rise to worrying scenarios for the future. Summer water stress causing the periodical death of the weakest trees, the extremely poor and episodic fruiting, the very likely seed sterility, the heavy anthropic disturbances and the lack of active protection measures are the main threats in the conservation of this species. Furthermore, the long geographic isolation and the small populations’ size severely reduced gene flow, promoting a rapid loss of intra-specific genetic variability.

The project is carried out by a partnership composed by the Institute of Biosciences and BioResources (IBBR-CNR), the Dipartimento Regionale Ambiente Sicilia - DRA, the Dipartimento Regionale Sviluppo Rurale e Territoriale - DRSRT, Legambiente and the Conservatoire Botanique National de Brest - CBNB (France) The main goal is to ensure the survival of Z. sicula through in-situ and ex-situ conservation actions. It entails technical, political/legal and education/awareness actions. The specific objectives consist of:

• improving the structure and vigour of the residual populations by limiting existing negative factors influencing it;
• increasing the number of individuals and building up novel populations of Z. sicula in ecologically suitable sites;
• monitoring activity in order to obtain precise information on the actual population size on its whole distribution area;
• involving competent authorities and local stakeholders in conservation actions;
• accomplishing legal protection (e.g. establishment of a protected area), and its recognition in the list of priority species of Habitats Directive;
• promoting divulgation and awareness, remarking the symbolic value of this special case of “species at risk” in the framework of the global problems of biodiversity conservation.;

The multiplication of the target species is one of the top actions of the project. Zelkova will be propagated through in-vitro and in-vivo techniques, according to protocols to be designed at the laboratories of IBBR and CBNB. The multiplication material will be massively produced and acclimatized in the laboratory and the nursery of the CBNB and the Centre for Germplasm Conservation of Marianelli (Siracusa) managed by the DRSRT. The new plant stock will be employed to reinforce the species in the current sites, and to establish new populations in novel sites. A conspicuous stock representative of the natural populations will be cultivated at the CBNB and the Centre for Germplasm Conservation in the aim to conserve the as highest possible genetic diversity of the species.

Genetic analyses, at both intra- and inter-population level, will be carried out in order to address the long conservation planning.

Considering that Z. sicula is assumed to thrive in typical forest habitat, actions of restoration and rehabilitation of the current habitat need to be carried out, in order to create a more suitable ecological environment for the relic population and to improve the stability and ecosystem functionality.

In the aim to improve conservation in front of the predicted climate changes, five pilot experiments of re-introduction according to principles of Assisted Colonisation will be carried out also in bioclimatic conditions different than the current ones, privileging protected areas and forest sites already included in public properties.

Formal procedures for the recognition of Z. sicula in the list of priority species of the Habitats Directive will be accomplished under the auspices of the DRA.

Finally, education and dissemination actions will be undertaken to improve awareness about the importance of the biodiversity conservation.

Key words: Biodiversity conservation, In-vitro and in-vivo propagation, Habitat restoration, Relic species