The conservation of rare species often requires the maintenance of an ex situ, or off-site, collection in addition to the monitoring of plants in their natural habitats. "Off-site" (or ex situ) work happens away from the plant's habitat. "On-site" (or in situ) work occurs at the plant's habitat (home in the wild). In situ and ex situ methods combined increase the plant's chance of survival in the wild.
Tropical plants, also bromeliads, are popular ornamental and indoor plants, as they provide a diverse and exotic collection of plants. Consequently many bromeliad species (an estimate ranges around 60% of natural bromeliad species) can be found in ex situ collections, far away from their natural habitats. They can be found in private collections of plant aficionados, of commercial growers as well as in public collections of botanical gardens worldwide. There typical ex situ techniques might involve the creation of living collections (either in soil or tissue culture), or long-term storage collections (e.g. seed or spore banks, or in liquid nitrogen as a bank of cryo-preserved material). Historically, ex situ techniques have been widely and successfully used to conserve plants of commercial value, but have been under-used in the conservation of wild plants. The importance and use of ex situ techniques in conservation has increased over the past decade thanks, in part, to their recognition in the Convention on Biological Diversity (UN, Rio de Janeiro, 1992). More recent, the Global Strategy for Plant Conservation contains specific targets for the ex situ conservation of threatened species.
Even so, in all kinds of ex situ collections, important problem are that
Genetic diversity is the primary source for variation in morphological appearance of plants as well as for the physiological adaptability, which acts as a buffer against harmful environmental changes. The current trend on hybridisation of originally non-neighbouring bromeliads therefore, is a threat to natural bromeliads since the original genetic information gets lost and fresh plant material is always needed. The irreversible loss of single genes or combinations of genes in genotypes, the so-called gene-erosion, is of major concern to today’s conservationists. In the context of conservation the collection of species and their vegetative propagation with pups as clones should be favoured
The private and public collections of bromeliads make up an important part of conservation efforts. Botanical gardens were originally founded to host large collections of plants for research as well as for the public to explore exotic or rare species. In regard to the current global biodiversity crisis, tasks and responsibilities are growing, especially since such institutions have a certain educational role. In terms of the educational tasks, botanical gardens can contribute to the general understanding of biodiversity, its values and threats, and thus create acceptance for conservation and related legislation. In addition, botanical gardens hold an important portion of the world’s genetic diversity resources by establishing seed banks, nurseries and tissue cultures in laboratory test tubes for parts of the global flora. The new role and activities of botanical gardens for conservation has been acknowledged and defined by the Convention on Biological Diversity’s Art. 9 as e.g.:
Bromeliad growers and collectors can enhance conservation efforts through their own collections. If you care for your collection in an appropriate way, you reduce the risk of diseases and mortality rates. By providing a vital population with high genetic variance, you can contribute to the world wide markets of bromeliad species and take pressure off of wild species.
Ex-situ programs are not a replacement for the conservation of wild plants and wild areas, and their effectiveness should not be overestimated. But such measures can be complementary to in-situ conservation, which represents a key action to conserve the viability of ecosystems and biodiversity, which, among others, is so essential for human welfare.
Vera Porwollik & Pierre L. Ibisch (BSI Conservation Chair)
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