Botanic gardens help protect plant diversity across the globe

An unprecedented study of plants conserved outside of their natural habitats has found that 30 percent of all identified plant species are contained in botanic gardens across the globe. 41 percent of all plant species classified as “threatened” are included in the gardens.

The study by researchers from the University of Cambridge also revealed that almost two-thirds of plant “genera” are housed in the world’s network of botanic gardens, and over 90 percent of plant families are represented.

On the other hand, the researchers found a notable imbalance between gardens in temperate and tropical regions. They discovered that a great majority of all plants species grown “ex-situ,” or outside of their natural environments, are located in the Northern Hemisphere.

Because of this, 60 percent of temperate plant species were represented in the botanic gardens compared to only 25 percent of tropical species. Most plant species are tropical, so they would be expected to be conserved in higher numbers.

The research team analyzed datasets compiled by Botanic Gardens Conservation International (BGCI). They compared the 350,699 known plant species with the species records of 1,116 botanic gardens. Despite housing almost half of all threatened species, the botanic gardens had only around 10 percent of overall storage capacity dedicated to these imperiled plants.

The researchers say that botanic gardens are of “critical importance to plant conservation,” and global efforts are needed to protect more species of plants that are at risk of extinction, especially those from tropical climates.

Dr. Samuel Brockington, the study’s senior author, is a researcher of Plant Sciences and a curator of the botanic garden at the University of Cambridge.

“The global network of botanic gardens is our best hope for saving some of the world’s most endangered plants,” said Dr. Brockington. “Currently, an estimated one fifth of plant diversity is under threat, yet there is no technical reason why any plant species should become extinct. Botanic gardens protect an astonishing amount of plant diversity in cultivation, but we need to respond directly to the extinction crisis.”

The study is published today in the journal Nature Plants.

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By Chrissy Sexton, Earth.com Staff Writer
Image Credit: Cambridge University Botanic Garden