Ex situ plant collections help address global challenges, but the complexities of these artificial ecosystems are not well understood, which impacts biodiversity conservation. Researchers from Cambridge University studied 100 years of botanic garden data to assess ex-situ plant diversity management.
They suggest that botanic gardens worldwide must work together to protect plant biodiversity, as species face extinction and restrictions limit wild collecting.
A study of botanic gardens worldwide shows they struggle to protect the most threatened plants from extinction. Researchers analyzed records from 1921 to 2021 from fifty botanic gardens, which currently grow half a million plants.
The findings suggest that the world’s living collections have reached peak capacity, and restrictions on wild plant collecting are hampering efforts to gather plant diversity. There is little evidence that institutions are effectively conserving threatened plants despite increasing extinction risks.
The study highlights that botanic gardens worldwide have not prioritized biodiversity conservation. Professor Samuel Brockington from Cambridge University Botanic Garden emphasizes the need for a united effort to conserve a diverse range of plants for research and reintroduction into the wild.
The report, published in Nature Ecology and Evolution, notes that the Convention on Biological Diversity (CBD) has reduced wild plant collection and created challenges for international plant exchange.
The impact of the garden surroundings on visiting pollinators
While the CBD demonstrates the power of international agreements, it hinders individual botanic gardens from working with many threatened plant species.
With 40% of the world’s plant diversity at risk of extinction, individual collections alone can’t prevent species extinction. Researchers suggest that botanic gardens must collaborate as a ‘meta-collection’ to store and safeguard plant diversity.
This involves sharing data and expertise and supporting new collections in the global south, where much biodiversity is found. While some institutions, like the Royal Botanic Gardens Edinburgh, have successfully conserved threatened species, such efforts are rare.
Living collections need constant replenishment, as plants typically live just 15 years. The analysis shows that the number of wild-origin plants peaked in 1993 and has declined since.
Professor Brockington notes that maintaining collection diversity, especially with wild-collected plants, is becoming harder. These plants are crucial for research and addressing climate change and biodiversity loss.
Climate change alters growing conditions, making it harder for botanic gardens to grow diverse species. Professor Brockington highlights that record temperatures in Cambridge affect plant survival. He suggests a rational, collective approach to determining the best locations for different species across the global network of living collections.
Data from the International Conifer Conservation Programme at the Royal Botanic Garden Edinburgh shows that living collections can significantly contribute to conservation if given the right resources and focus. By growing threatened species in a network of safe sites, the trees thrive and collectively represent strong genetic diversity.
Cambridge University Botanic Garden sought an ‘Expedition Botanist’ to lead global plant-collection efforts. Brockington emphasizes the importance of these expeditions for conservation and suggests that collaborative, ethical collecting is possible.
The Convention on Biological Diversity (CBD), signed by 150 leaders in 1992, promotes sustainable development, holds countries responsible for protecting their biodiversity, and ensures fair sharing of benefits.
Journal Reference:
- Cano, Á., Powell, J., Aiello, A.S., et al. Insights from a century of data reveal global trends in ex situ living plant collections. Nat Ecol Evol (2025). DOI: 10.1038/s41559-024-02633-z
Source: Tech Explorist
