Botanic Gardens Conservation International
BGCI provides a global voice for all botanic gardens, championing and celebrating their inspiring work. We are the world's largest plant conservation network, open to all. Join us in helping to save the world's threatened plants.

Global Strategy for Plant Conservation: Refinement of Target 8

Volume 3 Number 10 - June 2003

Peter Wyse Jackson

A review of the scope, terminology, base-line information, technical and scientific rationale of Target 8 included in the proposed Global Strategy for Plant Conservation

Target 8: 60 per cent of threatened plant species in accessible ex situ collections, preferably in the country of origin, and 10 per cent of them included in recovery and restoration programmes


The need for the adoption of measures for ex situ conservation of biological diversity is included in Article 9 of the Convention on Biological Diversity, predominantly for the purpose of complementing in situ measures. Parties shall adopt measures for the ex situ conservation of components of biological diversity, preferably in their country of origin, and measures for the recovery and rehabilitation of threatened species, including their reintroduction into their natural habitats.

Ex situ collections have also been recognised as actual and potential conservation resources for many purposes, including to provide accessible material of wild and cultivated germplasm for research; to help reduce collecting pressure on wild or in situ stocks and promote sustainable use and to provided security for livelihoods. Ex situ collections can also be used for educational purposes and to raise public awareness of conservation issues. Article 8(f) of the Convention (In situ conservation) outlines the need for measures to be taken to rehabilitate and restore degraded ecosystems and promote the recovery of threatened species. This target therefore addresses these aspects of the Convention for plants.

Ex situ conservation can be defined as measures taken to safeguard the components of biodiversity outside their natural habitats. Ex situ conservation is generally used to safeguard populations or individuals that are presently or potentially in danger of damage or loss. These losses are brought about by habitat loss and fragmentation, invasive species, pollution and other factors. Climate change may accelerate this loss. Ex situ conservation involves the collection, conservation and maintenance of samples of organisms outside of their natural habitats, usually in the form of plants, seed, pollen, spores, vegetative propagules, tissue or cell cultures and other genetic material of growing or preserved individuals. Threatened species can be variously defined according to different national systems in use or by the application of the IUCN Red List categories. The definition of the quantitative elements in this target depends upon the number of threatened species so recognised (target 3). The target does not specify to what extent ex situ collections of a particular species should be representative of the genetic diversity of a particular species in order to be regarded as conserved ex situ. In practice there is little comprehensive information available on whether existing ex situ collections are genetically representative. An increasingly frequent use of ex situ collections is to provide plant material for recovery and restoration programmes, including some species that have become extinct in the wild (probably over 100 species that are extinct in the wild are presently maintained in ex situ collections).

Recovery programmes may be defined as ones where genetically representative, self-sustaining populations of the species are established or re-established in the wild in appropriate natural habitats. In order to be successful, recovery programmes generally require the original causes of endangerment to be addressed. Recovery and restoration programmes for threatened species may adopt a single species approach, or focus on the conservation of all the components of an ecosystem, containing one or more threatened species. Such programmes represent the main methodologies used to integrate in situ and ex situ conservation as complementary but mutually supporting approaches. Integrated conservation can be defined as the combination of complementary approaches to in situ and ex situ conservation; it often involves drawing together different organisations and stakeholders to maximise a range of appropriate supporting methodologies (Wyse Jackson & Sutherland, 2000). If material from ex situ collections is used for recovery and restoration programmes is must be genetically appropriate for such use.

Background and Baseline

Ex situ collections

Ex situ conservation of plants is practised by a wide variety of bodies, especially genebanks (seed bank, field genebanks, in vitro collections) (FAO, 1996 & 1998) and botanic gardens and arboreta (Wyse Jackson and Sutherland, 2000). Significant ex situ collections are also maintained by other bodies, such as plant breeding and other experimental and research institutions, which may be of importance for plant conservation. Ex situ conservation collections are sometimes interpreted to include herbaria of dried or preserved specimens, when these collections contain material that supports biological or conservation research or when they contain actual or potentially functional genetic material, including seeds, spores, pollen and DNA. A sizeable proportion of the world’s vascular flora is currently represented in existing ex situ collections, although precise figures are not yet available. According to the FAO World Information and Early Warning System (WIEWS) database, approximately six million accessions are contained in over 1,300 genebanks, with over 5.5 million of those accessions stored in regional or national genebanks and c. 600,000 maintained within the Consultative Group on International Agricultural Research (CGIAR) system (FAO, 1998). Many of these collections are included in the International Network of Ex Situ Collections under the auspices of FAO (including the collections of the International Agricultural Research Centres – IARCs). Seed storage accounts for about 90% of the total accessions held ex situ (FAO, 1996).

The composition of these collections is not fully known and information on the types of collections held are only available for approximately one third of the accessions listed in the WIEWS database. However, it has been estimated that 48% of all accessions are advanced cultivars or breeders’ lines, while over one third are landraces or old cultivars and about 15% are wild or weedy plants or crop relatives (FAO, 1996). BGCI estimates that in excess of 80,000 plant species are in cultivation in botanic gardens worldwide, represented by some 6,130,900 living plant accessions in 2,178 botanic gardens (Wyse Jackson et al., 2001). A recent preliminary electronic analysis of accession information from 445 botanic gardens (undertaken by BGCI in 2002) indicated that between them they cultivate 80,070 taxa, of which 8,823 are species included in the 1997 IUCN Red List of Threatened Plants (Walter & Gillett, 1998). There is clearly very considerable capacity amongst the botanic gardens of the world for the maintenance of ex situ collections. In addition, Laliberté (1997) reports that 152 botanic gardens have seed/genebanks containing at least 255,832 accessions and an additional 17,069 germplasm accessions in botanic garden field genebanks. Of the long-term botanic garden seed banks surveyed by Laliberté, approximately 77% of their accessions are of germplasm collected directly from the wild. These same seed banks estimated that approximately 27% of their accessions are of rare and endangered species. An example to note is the Millennium Seed Bank (MSB) of the Royal Botanic Gardens, Kew. It aims to collect and conserve 10% of the world’s seed-bearing flora (some 24,000 species), principally from the drylands, by 2010 (Roger Smith, pers. comm. 2002). The MSB has already collected c.97% of the UK Flora (229 spp. of which are on the national Red list).


The world’s vascular flora is already very well represented in herbaria. As most described taxa are represented by one or more preserved type specimens, it is fair to suggest that almost all the known plant species are represented in ex situ collections.

Threatened Plant Species

IUCN currently estimates that there are 5,611 plant species which have been assessed and found to be threatened (according to IUCN’s 1994 Red List categories) (Hilton-Taylor, 2000). This is a very small number, relative to the total number of plant species known worldwide. However, it reflects the small number that has yet been assessed according to these 1994 IUCN categories. Oldfield et al. (1998) document over 7,300 globally threatened tree species, which they suggest represents nearly 9% of the world’s trees (of which 1,665 are known in botanic garden cultivation - BGCI figures, 2002). If a similar percentage can be applied to the complete world flora, then a total of 30,000 or more plant species may be threatened. However, in some regions the total is considerably higher than this, for example, Master et al. (2000) suggest that 33% of the flowering plant species in the USA are threatened with extinction. The earlier 1997 IUCN Red List of Threatened Plants (Walter & Gillett, 1998) documented nearly 34,000 species (or 12.5%) of the world’s flora facing extinction, using the pre-1994 IUCN Red List Categories. However, they acknowledge that this is just ‘the tip of the iceberg’ as much information is lacking from a number of biodiversity-rich countries. However, it is reasonable to give a conservative estimate that the actual world threatened plant flora lies somewhere between 30,000 and 60,000 species at the present time, although this total may climb significantly over the coming decades


Providing access to their collections through exchange of plant material is a standard practice for the majority of ex situ collections. An informal exchange system between botanic gardens has operated for decades by means of an Index Seminum, that is sent regularly to other botanic gardens, and a variety of research institutions worldwide. These seed lists contain information on material available within collections for exchange (mainly seeds and sometimes information on provenances). Such material is generally only available to support scientific research, collections development and for conservation purposes. The exchange of such material between botanic gardens is increasingly regulated by means of voluntary codes of conduct and material transfer agreements (to bring such access in line with CBD provisions). Few botanic gardens provide access to their collections for commercial purposes. Concerning botanic garden seed banks, 82.6% of long-term botanic garden seed banks surveyed by Laliberté (1997) have a distribution policy.

Information and data on the living plant accessions in ex situ collections is increasingly becoming available in electronic formats. Some institutions are providing access to such information through their web sites and contribute to electronic data compilation projects (such as a current project by BGCI to compile a preliminary checklist of taxa in cultivation in the world’s botanic gardens, due for publication in 2003).

Material stored in the world’s herbaria has also been widely accessible.

Country of Origin

Twelve countries have 45% of the germplasm accessions held in national collections (FAO, 1998) and c.57% of the world’s botanic gardens are situated in Europe (including the countries of the former Soviet Union) and North America (Wyse Jackson et al., 2001), indicating that there is a very uneven spread of facilities available for ex situ conservation. Nevertheless, many new institutions, such as botanic gardens, have been established in many countries in recent years and this uneven distribution is beginning to be addressed (Wyse Jackson et al., 2001). However, no studies have yet been undertaken to determine the level of ex situ conservation resources needed in order to deliver the ex situ conservation of plants in each country. At the present time no figures are available on the proportion of ex situ collections that contain accessible collections of the flora of their own countries. Increasingly, access laws and best practice require that primary accessions of ex situ collections are to be lodged in their country of origin.

Rationale and Conclusions

To summarise the points above:


  • Ex situ is an essential complement to in situ and should be seen as part of an integrated package. To achieve the target given it will be necessary to have a measure of the number of threatened plant species available. Using these ball-park figures, it can be suggested that in order to achieve the target of 60%, between 27,000 and 54,000 threatened plant species will need to be included in ex situ collections. Similarly, if 10% of threatened plant species are to be included in recovery and restoration programmes, then between 6,000 and 12,000 species must be targeted.
  • The development of a sub target should be considered, as a priority, to include 90% of critically endangered species in accessible ex situ collections during the target period.
  • Although ex situ collections contain very considerable collections currently, it will be necessary to increase the rate of accessioning of new material, of priority rare and endangered species, if the target figure is to be reached. This may involve accessioning between 2,000 and 3,000 additional threatened species into ex situ collections each year to meet the target.
  • There are many gaps in the baseline data. We still have limited information on the composition of ex situ collections in many countries and the proportion that are threatened. We know insufficient details on the extent to which ex situ collections are situated in their countries of origin. The extent to which ex situ collections have been used in recovery programmes is also inadequately known.
  • It is concluded that the inclusion of 60% of the world’s threatened flora in accessible ex situ collections is achievable by 2010, considering the widespread availability of existing well established ex situ conservation facilities and the extent to which the world’s flora is already represented in such collections. However, very considerable changes in institutional priorities, policies and practices will be required in many ex situ facilities if this target is to be reached. An important component in achieving this target will be in building and applying new capacity for ex situ conservation in countries in several priority regions, including Africa, Asia, Latin America and the Middle East, to ensure that ex situ conservation can be carried out increasingly and effectively in the country of origin. Ensuring that 10% of the threatened flora can be included in recovery and restoration programmes is a much more challenging target, but one which can be reached with careful planning and co-ordination, inter-institutional, national and international co-operation and with determined implementation of well focused national or regional plant conservation strategies.