GENMEDOC an inter-regional network of mediterranean seed banks

"ex situ" versus "in situ" conservation

Conservation is implemented through a field of various complex and combined actions. However, the techniques of "in situ" and "ex situ" conservation, both essential for the protection of species, reveal some weak points. In situ conservation, which is efficient when the number of individuals is sufficiently high, encounters a major limitation when there are problems with habitat fragmentation and subsequent reduction of the population size; thus, it is insufficient when there is a very limited number of individuals since, in that case, we face genetic erosion. On the contrary, in the framework of ex situ conservation, where there is a lack of interaction between the individual and the environment, only a part of the genetic variability of a taxon is preserved.


Photo (from the left) : River Park of Alcantara (Sicily), an example of "in situ" conservation (© 2005 Giovanni Spampinato); example of "ex situ" conservation (with the kind permission of the Millennium Seed Bank)

In order to have the greatest probability of success, the two techniques should be applied in a synergistic way in the field and must then be defined in a continuum that could be summarized as follows:

- protect the habitat where the species can live and reproduce, through appropriate legislative measures (Parks, Protected Areas, etc.);

- study the reasons for the regression of the species in nature and / or those reasons that restrain its spontaneous reproduction;

- collect seeds or seedlings without damaging the original population and ex situ cultivate a significant number of individuals;

- re-introduce the species in its natural habitat, with all the necessary precautions taken to assure a definitive implantation. It is only after a close collaboration between the centres of ex situ conservation and the centres of in situ experimentation, as anticipated in article 9 of the Convention on Biodiversity, that the expected results will be obtained.

In situ vs. ex situ : although most of the centres of "ex situ" conservation are located in industrialised countries, those devoted to "in situ" conservation are dislocated mainly in the tropics (countries under development). This discordance, which is figured in the distribution map of the world’s 500 Botanical Gardens richest in vascular plants, represents a great opportunity but also an important responsibility, which is explained in the articles 15-19 of the Convention on Biodiversity.(15-19).
(source :BIOMAPS - Biodiversity Mapping for Protection and Sustainable Use of Natural Resources)