The global network of botanic gardens needs to collaborate to protect plant biodiversity as the extinction crisis intensifies and wild-collecting becomes increasingly restricted, according to a team of researchers.
A significant study focusing on botanic gardens worldwide has uncovered their ongoing challenges in a crucial mission: preserving the most vulnerable plants from extinction.
Researchers examined a century’s worth of data—spanning from 1921 to 2021—across fifty botanic gardens and arboreta that currently cultivate around half a million plants, to assess how living plant collections have evolved over this period.
The findings indicate that these living collections have collectively maxed out their capacity. Additionally, global restrictions on collecting plants from the wild are proving to be obstacles in acquiring the plant diversity necessary for effective study and conservation.
Despite the rising extinction risks, there is scant evidence that institutions are successfully conserving threatened plants on a global scale. This suggests that the urgency of biodiversity loss has not been given due priority among botanic gardens worldwide—a situation that researchers stress needs immediate attention.
Professor Samuel Brockington, the curator of the Cambridge University Botanic Garden and the lead investigator, stated, “A united, collaborative effort from all botanic gardens is now essential to preserve a genetically varied selection of plants, making them accessible for research and future reintroduction into their native habitats.”
In their report published in the journal Nature Ecology and Evolution, the team notes that the Convention on Biological Diversity (CBD) has effectively reduced wild plant collection efforts by about half and has also introduced barriers to the international exchange of plant species.
Brockington, who also holds a professorship in Evolution at the University of Cambridge’s Department of Plant Sciences, remarked, “The CBD highlights the significant impact of international treaties. However, it seems to hinder individual botanic gardens from collaborating on the conservation of many globally endangered plant species that we could potentially help rescue from extinction.”
Collective mindset
As much as 40% of the planet’s plant species face heightened extinction risks. Recognizing that individual collections have limited capacity to single-handedly prevent species extinction calls for a reevaluation of how they can work together to store and maintain biodiversity in living collections.
According to the researchers, treating these living collections as a ‘meta-collection’ in the future will be crucial. Coordinated efforts among botanic gardens will enable them to host a diverse range of plants necessary for impactful conservation activities. This collaboration will involve sharing data and expertise and fostering the creation of new collections in regions of the Global South, where a significant portion of the world’s biodiversity is found.
The researchers highlight that some individual institutions, like the Royal Botanic Gardens Edinburgh, have successfully focused on and conserved specific threatened conifer species. Likewise, the Botanic Gardens Conservation International (BGCI) has initiated various global conservation partnerships. Nonetheless, such initiatives remain the exception rather than the norm.
Decline in the wild
To maintain living collections, plants must be consistently replaced or propagated, given that the average lifespan of a specimen is only about 15 years. However, the analysis revealed that the number of plants sourced from the wild has been in decline since its peak in 1993.
“Sustaining the diversity of our collections is certainly becoming more challenging. This is particularly true for wild-collected plants, which are crucial for our research endeavors and for addressing the dual issues of climate change and global biodiversity loss,” commented Brockington.
Concerns about climate
As climate change modifies growing conditions across various regions, individual botanic gardens will find it increasingly difficult to cultivate such a wide diversity of species.
Brockington noted, “Climate change directly impacts our operations by altering local weather; we have witnessed record-breaking temperatures in Cambridge in recent years. This influences the survival of our plants, prompting us to strategically and collectively determine the best locations for different species within the global network of living collections.”
On July 25, 2019, Cambridge University Botanic Garden registered a temperature of 38.70C—the highest ever recorded in the UK at that time.
Importance of diversity
Genetic diversity is crucial for protecting at-risk plant species, as it facilitates the creation of breeding populations capable of adapting to future challenges. The greater the number of individual plants within a collection, the higher the level of genetic diversity.
The research team asserts that the International Conifer Conservation Programme, overseen by the Royal Botanic Garden Edinburgh, demonstrates that living collections can significantly contribute to conservation when provided with adequate resources and focus. By dispersing threatened species across secure sites, the trees are reared in optimal conditions, collectively representing a robust sample of the genetic diversity of this vital group.
Ethical collection practices
Last year, the Cambridge University Botanic Garden sought a new ‘Expedition Botanist’ to lead global plant-collection ventures and contribute to essential conservation efforts.
Brockington emphasizes that these expeditions are still critical for safeguarding and studying plant species worldwide. He believes that collaborative collection endeavors are feasible in a just and ethical manner that fosters equitable international partnerships.
The CBD is a global treaty established in 1992 by 150 national leaders aimed at promoting sustainable development. It designates each country with the responsibility for protecting its biodiversity and encourages fair sharing of the benefits derived from using this biodiversity.
Globally, there are 3,500 botanic gardens and arboreta whose purpose is to facilitate scientific study, conserve, and provide access to the world’s plant species, in addition to showcasing them to the public.
Botanic Gardens Conservation International (BGCI) is an organization dedicated to rallying botanic gardens and engaging partners to ensure plant diversity benefits both people and the planet.
