The human destruction of living things is causing a “frightening” number of plant extinctions, according to the first global analysis of the problem published in the journal Nature Ecology .
For the first time, researchers from the prestigious Royal Botanic Gardens in Kew (UK) and Stockholm University (Sweden) have compiled a global analysis of all documented plant extinction records around the world.The study shows how many species of plants have gone extinct in the last 250 years, what they are and where they have disappeared from.
They found that almost 600 species of plants have disappeared in the last two and a half centuries.This figure was calculated after one of the study authors, Kew scientist Rafaël Govaerts, reviewed all the publications on plant extinctions for more than three decades and found thatthe number is four times greater than the current list of extinct plants.
“Most people can name a mammal or bird that has become extinct in recent centuries,but few can name an extinct plant. With this study it is the first time that we have an overview of which plants have become extinct, from where they have disappeared and how fast this is happening “, explains Aelys M Humphreys, co-author of the work.
By reviewing these data, the scientists discovered that plant extinction occurs much faster than “natural” extinction rates (the normal rate of loss in Earth’s history before human intervention),up to 500 times faster. Animals are also disappearing much faster than theorized,at least 1,000 times faster. The study authors believe these figures underestimate the actual levels of ongoing plant extinction.
The scientists found that the highest rates of plant extinction are found on islands, in the tropics, and in areas with a Mediterranean climate – regions of typical biodiversity that are home to many unique species vulnerable to human activities . The authors also found that plant species that are woody (such as trees and shrubs) and with a small geographic range (such as those limited to small islands) are more likely to be declared extinct. These results suggest that the increase in the rate of plant extinction could be due to the same factors that are documented as threats to many surviving plants: the fragmentation and destruction of native vegetation that results in the reduction or loss of habitat of many species of restricted range.
Extinct plants
Lost plants include the sandalwood from Chile, which was exploited for essential oils, or the pink-flowered Santa Elena olive tree. L higher as losses occur in the tropics and islands, which are home to trees of great value and tend to be particularly rich in plant diversity.
Analysis of the plants found that Hawaii had the most recorded extinctions (79), followed by the Cape provinces of South Africa (37), with Australia, Brazil, India and Madagascar also among the top regions. However, there may well have been so many extinctions in places that have been less studied.
However, a positive conclusion from this work has been the evidence that some plants once believed to be extinct have been rediscovered, such as the Chilean saffron.
Why does the extinction of plants matter?
All life on Earth depends on plants, as they provide the oxygen we breathe and the food we eat. Plant extinctions can lead to a complete cascade of extinctions in other organisms that depend on them, for example insects that use plants for food and to lay their eggs.
Rob Salguero-Gómez, a member of the British Society for Ecology Committee and Associate Professor in the Department of Zoology at the University of Oxford who was not involved in the study, commented:
“Plants support and provide key resources for entire ecosystems around the world. However, much of the effort to quantify the loss of species diversity around the world has focused on charismatic species, such as mammals and birds. Understanding how much, where and how plant species are being lost is of utmost importance, not only for ecologists but also for human societies.We depend on plantsdirectly for food, shade and building materials, and indirectly for ‘ecosystem services’ such as carbon fixation, oxygen creation and even the improvement of human mental health through green spaces ”.
“The study by Humphreys and his colleagues examines how much plant diversity has been lost in recent centuries, using detailed records dating back to the time of Carlos Linnaeus. The authors found that previously reported extinction rates for plants are very underestimated, since in the last centuries a quantification of extinction was found that was multiplied by four compared to those present in the IUCN Red List of species.The researchers of this examination in the plant kingdom found that approximately 2.3 species of seed-forming plants have become extinct per year in the last 250 years,an even more alarming rate if one considers that the general rate of extinction has more than doubled in the last hundred years “, clarifies the expert.
Referencia: Global dataset shows geography and life form predict modern plant extinction and rediscovery. Aelys M. Humphreys, Rafaël Govaerts, Sarah Z. Ficinski, Eimear Nic Lughadha & Maria S. Vorontsova. Nature Ecology & Evolution (2019) DOI: https://doi.org/10.1038/s41559-019-0906-2
