The most in-depth species survey to date finds an “astonishing array” of plant diversity in the global botanic garden network, including 41% of all endangered species. However, researchers find a significant imbalance between tropical and temperate plants, and say even more capacity should be given to conservation, as there is “no technical reason for plant species to become extinct”.
The world’s botanic gardens contain at least 30% of all known plant species, including 41% of all those classed as ‘threatened’, according to the most comprehensive analysis to date of diversity in ‘ex situ’ collections: those plants conserved outside natural habitats.
The study, published today in the journal Nature Plants, found that the global network of botanic gardens conserves living plants representing almost two-thirds of plant genera and over 90% of plant families.
However, researchers from the University of Cambridge discovered a significant imbalance between temperate and tropical regions. The vast majority of all plants species grown ex situ are held in the northern hemisphere. Consequently, some 60% of temperate plant species were represented in botanic gardens but only 25% of tropical species, despite the fact that the majority of plant species are tropical.
For the study, researchers analysed datasets compiled by BGCI. They cross-referenced the working list of known plant species – currently sitting at 350,699 – with the species records of a third of botanic gardens on the planet, some 1,116 institutions. They say this provides a “minimum estimate” for the plant diversity held in botanic gardens.
However, while gardens hold approaching half all threatened species, just 10% of overall storage capacity is dedicated to such plants. The researchers argue that botanic gardens are of “critical importance to plant conservation”, and internationally coordinated efforts are needed to house even more species at risk of extinction – particularly those from tropical climates.