Plants play a critical role in maintaining life on this planet. They sit at the base of the trophic pyramid, providing food all the way up the chain to humans at the top. They provide services such as climate regulation and flood defence. They contribute to soil formation and nutrient cycling, and they provide us with shelter, medicines and fuel.

 

Despite this, the Millennium Ecosystem Assessment (2005) estimates that between 60,000 and 100,000 plant species are threatened with extinction – equivalent to around one-quarter of the total number of known plant species.

Millennium Ecosystem Assessment: https://www.millenniumassessment.org/documents/document.356.aspx.pdf

According to the Secretariat of the Convention on Biological Diversity (2010), the main threats are land-use change and over-exploitation, with climate change expected to exacerbate the situation.

Convention on Biodiversity

Conserving Species in Seed Banks

With the range of techniques available to us, there is no technological reason why any plant species should become extinct. Over 90% of seed-bearing species studied to date produce desiccation-tolerant (‘orthodox’) seeds. Following drying, orthodox seeds are capable of surviving long-term storage under cold conditions. Storage life approximately doubles for each 5ºC reduction in storage temperature. Theoretically, seeds may survive for many decades, centuries and even millennia. Finally, after storage, provided that seed dormancy can be removed, it is relatively easy to germinate seeds and propagate plants.

Where possible, plant populations should be conserved and managed in-situ– in the wild. The aim of seed banking wild species is not to compensate for in-situ conservation but to complement it. Its foremost aims are to:

• Provide proper seed material (for reintroduction programmes and reinforcement of endangered populations at their natural site)
• Conserve genetic resources (for research and applied use)
• Provide and control access to seed material for research

In addition, skills, knowledge and data from seed banks support wider plant conservation activities, for example, by the provision of field data on the status of wild plant populations, or new germination protocols for little-known species.

Seed banks play a significant role in securing the survival of plant species by removing collections of seeds and securing them in safe havens for long-term storage. They provide the insurance opportunity for species lost in the wild to be reintroduced.

Seed banks are also increasingly recognised as a source of founder propagation material where species translocations become necessary to overcome their inability to migrate at the pace needed to successfully adapt to the rapid change in environmental conditions due to climate change.

Compared with other methods of plant ex-situ conservation (such as field gene banks, botanical garden plant collections, in vitro material, pollen banks and DNA banks), seed banking offers many advantages including, potential storage for centuries, small space requirements, low tech solutions, relatively low costs, and maintenance of pure lineages.

An Example of a Seed Banking Network, on Mediterranean Islands

The Mediterranean Basin is a biodiversity hotspot with 25,000 plant species – one in ten of all known plants, of which over half are endemic to the region. It is however amongst the four most significantly altered biodiversity hotspots on Earth with less than 5% of its total land area protected in nature reserves. This means that, as well as being vulnerable to changes in climate, the majority of plant species are unprotected from changes in land use caused by activities like tourism and agriculture.

 

Nowhere is this threat felt more than on islands where high levels of biodiversity and endemic richness are combined with a wide range of habitats within a small but restricted area, reducing the opportunities for species migration when conditions change.

The “Ensuring the survival of endangered plants in the Mediterranean” project, funded by the MAVA foundation, is an initiative led by seven conservation organisations from Sicily, Sardinia, Cyprus, Corsica, Crete, Mallorca and the UK working together to protect the endangered flora of the six islands through ex-situ seed conservation. The first phase of the project has run for three years between October 2011 and September 2014 and has seen many successes:

• Seeds have been collected from mainly endemic, rare, threatened or protected taxa, stored in local seed bank facilities on the six islands and backed up at the Millennium Seed Bank. This has resulted in the protection of over 900 endangered plant taxa.
• Germination tests continue to be carried out to assess the viability of the material and to ensure regeneration is possible. Data from this research, including germination protocols, is available to aid in conservation and restoration activities.
•  The project has enabled a network of seed conservationists in the Mediterranean Basin to be developed. This has improved local conservation initiatives, built relationships and facilitated resource sharing between institutes and staff working in seed conservation across the Mediterranean linking, for example, seed banks with universities and other research facilities.
• A programme of joint seed collecting trips has forged relationships as well as improved local knowledge about the ecology and taxonomy of the flora of all six Mediterranean islands.
• The project has included higher-level training with MSc and PhD support as well as a number of publications.
• There have been two PhD summer schools, organised by the project’s partner at the University of Cagliari in Sardinia, with the themes:
• Forest conservation and management in Sardinia
• Conservation and management of plant diversity in hotspots.
• The project has also been widely publicised and helped to increase public awareness of the value and vulnerability of the local flora.

There have been a few unexpected surprises along the way, including the discovery in a gorge in Crete of a population of Hypericum aegypticum subsp. webbii, previously thought to be extinct, and the discovery of populations of Bellium artrutxensis in Mallorca and Ibiza, previously only recorded in Minorca.

The first phase of this vital project has been a success on a number of levels and should pave the way for future plant conservation activities in this fragile region.

More information on seed banking can be found here:

www.kew.org/science-conservation/millennium-seed-bank

and the “Ensuring the survival of endangered plants in the Mediterranean” project can be found here:

www.medislandplant.eu