Botanical gardens have no room to grow. It is the main conclusion of a recent study published in Nature Ecology & Evolutionwho has revealed that The world collection of living plants have reached their maximum capacity. In broad strokes this means that “there are no” more species, which endangers the conservation of the most threatened, which can be extinguished before we know and preserve them.
There are about 3,500 botanical gardens throughout the globe. For this work, the researchers analyzed a century of records in 50 of them, among which are some of the most important in the world and the Botanical Garden of the University of Valencia as the only Spanish case. Together, the spaces of the sample cultivate half a million plants. The objective of the study was to see how the collections of living plants in the world have changed since 1921, and the result is not flattering.
Ángela Canothe main author of the study and conservative of the Botanical Garden of the University of Cambridge, warns the reason that the ability of these spaces to house collections of living plants reached its peak in 2009limiting efforts to preserve global plant diversity since then. “Botanical gardens are full. We are running out of space and without resources. Meanwhile, the rhythm at which plants appear in the lists of threatened species increases much faster than the rhythm we manage to answer (discover, study and keep them). The risk of extinction accelerates and our response is very slow, “he says.
The Cambridge garden houses more than 8,000 species, overcoming the diversity of countries like Vietnam. However, the proportion of threatened species in their collections is very low, between 200 and 300, which reflects a global trend. But the study does not speak of “space” attending only to the available square meters, “if not the resources that botanists have to conserve in their collections rare species,” Cano details. “Given these factors, we conclude that we are in a stagnation: We are not growing in number of plants or in number of species. We have reached a stop both in capacity and in diversity. “
And in Spain, have we also touched the roof? Jaime Güemesdirector and conservative of the Collection of Botanist plants in Valencia since 2018, offers a slightly different perspective. “If we talk about generalities, the study is right. It has reached a stop and it is due, rather than the space, that we have to generate the appropriate microhabitats for the species. Certain flowers cannot be put under the trees because they do not Sun the Sun; each space has its own characteristics. ” That limits the possibilities.
The good thing is that many of Our gardens are dedicated mainly to the conservation of native floraand that facilitates things with respect to gardens such as Cambridge or Kew (in the United Kingdom), which have more exotic species. “For example, the Botanical Garden of Castilla-La Mancha (Albacete), is dedicated to conserve Manchegas species and that of Sóller (Mallorca), was born to work in the Balearic flora,” he says. This localist model is the one that Güemes would reply throughout the world to preserve the biodiversity of the earth.
The main reason is that there is a clear imbalance: “The majority of botanists are located in global northern countries for historical reasons, so It is essential to create more botanical gardens in the southwhere the greatest amount of biodiversity is found; Much to discover. “However, Güemes also points out that” species cannot be preserved in botanical gardens only; There is a lot of work to make habitat protection and expeditions have fallen. “
“We do not know even 20% of all species that exist in the world; Field work is needed. So, rather than increasing the surface of the gardens, which can also be interesting, we have to direct conservation strategies to exploration and knowledge; allocate more resources to collect more plants in Asia, Africa and Latin America, and work in observatories in which there are millions of samples to study. “
An agreement that does not suit
For Cano, the main aggravation for the lack of space dedicated to conservation in botanists are international restrictions, which “hinder the exchange of plant material between botanical gardens from different countries.” The greatest stumbling block finds it in the United Nations Agreement on the biological diversity of 1993which was born to end the plant colonialism of Western countries and that gave sovereignty about biodiversity to the national governments themselves.
According to the study, since the introduction of the agreement, the number of plants collected in nature by botanical gardens has been reduced by half. “Political borders do not help us collectively manage biodiversity More threatened in the world, “says the author. Brexit is an example of this problem, making the exchange of plant material between European gardens more expensive. For her, the free exchange of specimens, seeds and data between institutions is essential for conservation, especially threatened species.
Botanical gardens are not only conservation spaces, but also research and education centers. However, as Cano points out, “although botanical gardens are collectively to the maximum of their capacity, probably We only dedicate between 5 and 10% of that capacity to this question of conservation“The researcher warns that climate change also threatens living collections, forcing gardens to prioritize plants that survive new climatic conditions.
That is why “regulating access to such plants in such a way that they protect themselves from commercial intentions, but that bureaucracy is facilitated for conservation intentions.” His study, he says, “is a call to action for governments, institutions and citizens to become aware of the importance of plant biodiversity and work together for conservation.”
In that sense, Güemes proposes greater collaboration between botanical gardens, creating a “metacolection” where individual specimens of threatened species are grown in multiple institutions and that there is a database that allows to improve communication so that “Not all botanical gardens are dedicated to conserving the same species”.
In line, the Cambridge researcher also points out that a worldwide coordinated effort is necessary, comparable to the projects of the human genome or the space station, to protect the plant wealth of the planet. “In the botanists 40% of the known flora is collected. We could reach 100% but for that we have to agree. “