Compared to many animal groups, the population and endangerment of most plant species have hardly been recorded worldwide or even continent-wide. Biologists have now investigated what this looks like for Europe in vascular plants. The result: Almost 7000 plant species occurring in Europe are classified as threatened in at least one European country. Seven to nine percent of the recorded vascular plants only occur in Europe and are endangered throughout their range.
Plants form the basis for almost all food chains and ecosystems on earth – it is correspondingly important to preserve their diversity. So far, however, there is only an estimate of the global endangerment status for around ten percent of all known plant species. So far, 90 percent of all plant species are missing from the global Red List of the World Conservation Union (IUCN). “Such data gaps can be fatal because they lead to uncertainties in the setting of priorities in international nature conservation policy,” explains first author Hanna Holz from the University of Halle.
National red lists and global distribution compared
In addition, there are many national Red Lists. However, they say little about how endangered or common a species listed there is in other countries or continents. In order to remedy this, Holz and her colleagues have now carried out a comprehensive assessment of the endangerment status of vascular plants, at least for Europe. Vascular plants include almost all plants except mosses, algae and lichens. For the study, the biologists evaluated the national red lists of 37 European countries from the years 1999 to 2020 and summarized the plant species listed there in a database.
“The geographic range of this data is from Portugal in the west to Romania in the east and from Norway in the north to Cyprus in the south,” according to the team. In all, the final listing included 20,000 to 25,000 species of vascular plants found in Europe, of which 7,192 were on at least one Red List. In order to find out where and how far these plant species are distributed beyond Europe, Holz and her colleagues compared this data with the “Plants of the World” database at Kew Gardens in England. This contains data on the geographical distribution of almost all known vascular plant species – a total of around 345,000 species.
A third is at risk
It turned out: “Almost half of all species recorded in our Red Lists are endemic to Europe,” the scientists report. These 3282 endangered species are only found in Europe, nowhere else in the world. Of the approximately 20,000 to 25,000 vascular plant species distributed on our continent, 7000 are classified as endangered in at least one European country – around a third. But the situation is even more worrying for the plants, which are endangered throughout their range – and which also have nowhere else in the world as a refuge.
This applies to around 1,800 species of vascular plants found in Europe, as Holz and her team determined: Seven to nine percent of all vascular plant species found in Europe are therefore endangered worldwide. The Mediterranean region and Sweden are particular hotspots for endemic plant species that are threatened throughout their range, as Holz and her colleagues report. A large part of these species has not yet been included in the still very incomplete global Red List of Plant Diversity. The national red lists also usually only cover half of all plants occurring in a certain country – which is why the current survey tends to underestimate the risk, as the team emphasizes.
Contribution to the UN biodiversity goal
According to Holz and her colleagues, their results are now helping to increase knowledge of the endangered status of global flora. If this methodology is also used on other continents, it could help to close the large gaps in the global Red List. This in turn would bring us closer to the goal of the United Nations Convention on Biological Diversity (CBD), which had set itself the goal of compiling a comprehensive list of endangered plant species by 2020 at the latest – a goal that could not be achieved. “With our results, we are now helping to update and expand the most important instrument of international nature conservation policy in this area,” says Holz.
Source: German Center for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig; Specialist article: Plants, People, Planet, doi: 10.1002/ppp3.10251