Fluvial systems of the Mediterranean region, with their specific dynamics and environmental conditions that are less extreme than those of their surrounding systems, are home to a mosaic of habitats with a high degree of biodiversity, and serve as a migration path for many species of flora and fauna. They also play a critical role in the life of human communities, who make use of their resources and benefit from them as spaces for leisure.
Fluvial systems in the Mediterranean region have been greatly altered by human activity, its channels and riverside areas having first been transformed into farmland, and more recently into urban developments. Human activity has also regulated flow volumes; canalisation projects have destroyed the connectivity between river courses and alluvial plains; and surface and underground water reserves are overexploited.
The restoration of fluvial ecosystems through the recovery of natural hydrological regimes is an unavoidable task in the face of such general deterioration. These interventions may require plantation projects as a means of recovering riverside vegetation in the short term. After these interventions, however, the river itself will eventually model the structure and the dynamics of its riparian vegetation.
In any event, the generation of reproductive materials for use in river restoration projects must try to ensure the viability of newly introduced populations, without causing an impairment of existing genetic resources. This is achieved, first of all, by proper species selection. Since these plantations are not developed for production purposes, autochtonous taxa and materials of local provenance should be favoured whenever possible. The genetic base of the chosen materials should also be as wide-ranging as available resources permit, in order to encourage adaptability of new populations. Alien species – some of which have already become naturalised in riverside areas of the Mediterranean region – must be particularly avoided, as well as species that may hybridise with the local ones.
This guide has been conceived as a support tool for nursery managers, and for others who are not specialists but are in one way or another involved in the production of riparian plant species for hydrological restoration projects. It offers useful data on the production of seeds, parts of plants and plants belonging to a large series of tree, shrub and lianoid species that may be employed in fluvial systems of the Mediterranean region. It provides information on species that are dominant in the riparian vegetation of the region, on species whose propagation may be of interest due to their potential interaction with some species of fauna and on species that are traditionally used for hydrological restoration purposes. Although some of the included taxons are not strictly riparian, but originate in the Mediterranean shrub and forest communities, they can develop optimally in these environments, especially in extremely dry areas.
The information is presented in the form of fact sheets that include details of the production of reproductive materials – from collecting to conservation –, the physical characteristics of seeds, and the most appropriate methods for generative or vegetative production of plants. General data on each taxon are also provided: geographical distribution, ecology, taxonomic identification features, and reproductive biology. The technical sheets include additional details that may be of use for improved management of reproductive materials. In particular, and whenever possible, information about intraspecific variation – and its implications in collecting and use of materials – is provided, with a view to promoting the conservation of genetic resources.
A series of attachments deal with certain specific matters that are directly related to the production and use of forest reproductive materials, such as intraspecific genetic variation and its relevance in terms of population adaptability, practical aspects of the production and conservation of seeds and parts of plants, and the European regulations applicable to the production, transport, and marketing of some species included in the present guide.
Another appendix includes tables and figures aimed at making it easier to identify species of the genera Populus, Tamarix and Salix that can be found in the European Mediterranean region. It was also considered of help to provide a glossary of the scientific and technical terms employed in the guide that are not commonly used by people this guide is addressed to.
We hope the guide proves to be a useful manual for plant producers, and that it contributes to the conservation and improvement of our Mediterranean riverine environments, which are part of our natural and cultural heritage.
