Humans have been interfering with nature on a large scale for centuries. This has fatal consequences for some living beings, while others even benefit. Biologists have now examined more closely which vascular plants are among the winners or losers of the Anthropocene. They came to a clear conclusion: Among the plants there are significantly more losers than winners – and the plants that are useful for us benefit the most.
The survival or extinction of species today is mostly linked to their compatibility with human activities. The species that are fortunate to be directly or indirectly boosted by human activities are likely to survive and can be considered “winners”. On the other hand, those who are pushed into ecological insignificance or extinction by the same activities are the final evolutionary “losers”.
Vascular plants in view
John Kress and Gary Krupnick from the National Museum of Natural History in Washington DC have now investigated how much the Anthropocene – i.e. the “Age of Man” – affected today’s plant diversity. To do this, they analyzed data on more than 86,000 species of vascular plants and assessed whether they belonged to the winners or losers of the Anthropocene based on distribution, abundance and endangerment status. They also investigated the role played by a plant’s usefulness for us humans.
“Our analysis is an attempt to identify and define the human factors that have shaped and will shape plant biodiversity in the future,” the researchers explain. Four additional categories included species likely to gain or lose in the future, plant species unaffected by humans, and those that are already extinct. However, the selected species represent only 30 percent of the nearly 300,000 known vascular plant species.
More losers than winners
The results clearly reflect the negative impact of humans on their environment: almost 20,300 plant species were not or are not able to deal with the human-induced changes in environmental conditions. They have become rarer, are considered endangered, or have been supplanted by other vascular plants. The majority of these “loser plants” belong to the species that cannot be classified as useful for humans, as the researchers report. In contrast, only about 7,000 vascular plants from the Anthropocene emerge as winners. “The results show that there are currently more losers than winners,” the team said.
Overall, there was a clear connection to the “usefulness” of plants for us humans: “The winners of today and tomorrow are above all the economically important plant species that people have cultivated over the last twelve millennia and that today account for up to 40 percent of the world’s population land area of the planet,” explain Kress and his colleague. Furthermore, unless there is a fundamental change in the behavior of people on Earth, there will continue to be more losers than winners: 26,002 species ended up in the category of potential losers, while the researchers classified only 18,664 plant species as tentative winners.
Plant life becomes more monotonous
The team also looked more closely at the plants’ pedigrees, looking for specific patterns in the distribution of winners and losers. “The question was whether there are some plant lines that contain more winners or more losers that we should be concerned about,” explains Kress. As it turned out, however, the winners and losers were mostly evenly distributed across the plant orders. The main exceptions were small tribes, which were more likely to be winners or losers than multi-species tribes, says Krupnick. The three phyla most at risk of extinction include the cycads, also known as cycads, and cypress plants, such as sequoias and junipers. An ancient family of conifers, the Araucariales, now mainly found in New Caledonia, is also particularly endangered.
One thing is clear to the researchers: If plants cannot adapt to the environment created by humans, they will die out. “Our results indicate that this means that the plant community will be much more homogeneous in the future than it is today,” explains Kress. This reduced diversity will have serious consequences for ecosystems, as a loss of plant diversity will inevitably lead to a loss of animal species. The respective ecosystem is less flexible and, as a result, less resilient to stress and changes. “This study suggests that we’re headed for a major loss in plant diversity — we’d better wake up,” says Kress.
Source: Smithsonian; Specialist article: Plants People Planet, doi: 10.1002/ppp3.10252