More 'losers' than 'winners' among plants in the age of humans
Date:
March 10, 2022
Source:
Smithsonian
Summary:
A new analysis spanning more than 86,000 plant species finds that
on this human-dominated planet, many more species of plants are
poised to 'lose' rather than 'win.' T
FULL STORY ==========================================================================
A new analysis spanning more than 86,000 plant species from John Kress,
botany curator emeritus at the Smithsonian's National Museum of Natural History, and Gary Krupnick, head of the museum's plant conservation unit,
finds that on this human-dominated planet, many more species of plants
are poised to "lose" rather than "win." The study was published today,
March 10, in the journal Plants, People, Planet.
==========================================================================
From changing Earth's climate to destroying, degrading and altering
ecosystems on a massive scale, human choices now largely dictate the environmental conditions across much of the globe and, as a result, which species of plants and animals can survive and persist and which will go extinct. Species lucky enough to be directly or indirectly aided by human activities are likely to survive and can be thought of as "winners,"
while those that are pushed to ecological irrelevance or extinction by
those same activities are the ultimate "losers" in evolutionary terms.
Kress encountered this concept of evolutionary winners and losers in
the age of humans (known to some researchers as the Anthropocene), in
the writings of John McNeill and wanted to see if it might be possible
to tally the plant species that were winning and losing now and in
the future.
"I actually started this project from a place of optimism," Kress
said. "I had just planted all these trees around my house in Vermont
and thought to myself that maybe there are actually more winners than
losers, and we are just focused on everything that's disappearing."
In the summer of 2019, Kress brought Krupnick into the fold to help
compile and analyze the mountains of data required to put every plant
species for which there was enough information into the categories of
winners and losers. The researchers split the winners and losers into
species that are and are not useful to humans.
In addition to these four categories, Kress and Krupnick created four
others: Species that appeared likely to win or lose in the future
were deemed tentative winners or potential losers, and species that do
not seem to be winning or losing at present were considered currently
neutral. A fourth and final category included 571 species that have
already gone extinct.
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To place plants in these categories, Kress and Krupnick combed through databases that listed endangered plant species, economically important
species such as crops, invasive and weedy plants, and endangered plants
that are involved in legal and illegal global trade.
In total, the researchers were able to place 86,592 species of
vascular plants -- a large group of plants that have vascular tissue
which transport water, nutrients and other substances -- into the
eight categories that describe their prospects for survival in the Anthropocene. That may sound like an inconceivably large number of
species, but it is actually just under 30% of the nearly 300,000 known
species of vascular plants. There simply was not enough data to categorize
the remaining 70% of global plant diversity, which reflects how much is
left to learn about Earth's botanical riches, Kress said.
The analysis revealed that losers currently outnumber winners, and
that losers are likely to continue to outpace winners in the future
if human impact on the planet maintains its current trajectory. Kress
and Krupnick categorized 20,293 species of plants as losers, with the
vast majority of those losing species being identified as not useful to
humans. By contrast, the researchers found just 6,913 species of winners,
with all but 164 of those species having some human use.
In the future, barring significant changes in how people conduct
themselves on Earth, losers are projected to continue to outnumber
winners, with 26,002 species in the potential losers category compared
to 18,664 species in the tentative winners category.
To look for evolutionary patterns within the clear winners and losers identified by the study, the researchers also mapped the locations of
these lucky and unlucky species on the tree of life.
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"The question was whether there were some lineages of plants that were
more packed with winners or were full of losers we should be concerned
about," Kress said.
As it turned out, winners and losers were for the most part evenly
distributed across plant orders. The exceptions came primarily from
small lineages, which were more prone than lineages with many species to leaning heavily in favor of winners or losers, Krupnick said. Three of
the lineages most at risk of extinction include cycads, the cypress family (which includes redwoods and junipers) and an ancient family of conifers
called the araucariales which are today mostly found in New Caledonia.
Branches of the plant evolutionary tree with few species and more losers
than winners such as these have an elevated risk of being lost altogether, taking with them everything there is yet to learn about their biology
and their lineage's genetic uniqueness.
"Now and in the future, plants have to adapt to the environment humans
have created or they will go extinct," Krupnick said. "Our results
suggest that this means the plant communities of the future will be more homogenized than those of today." This increased homogeneity is likely
to have serious consequences for ecosystems around the world as well as humanity. Losing plant diversity can drive a loss of animal diversity,
Kress said, and make ecosystems less resilient in the face of hardship
or change.
"The list of winners shows that we've selected certain species that
are useful to us, but as that pool of plants we have to select from
decreases in the future, humanity will have many fewer options when we
want to reforest the planet, find new medicines or foods, or develop
new products," Kress said.
Kress said he hopes that these lists will afford other researchers opportunities to look more in depth about why certain species of lineages
are winning or losing in the age of humans and to identify the plants
that are most in need of conservation.
"It still looks green outside my window, and that can create the illusion
that plants are doing well," Kress said. "But this study suggests we're
on course for a big loss of plant diversity, and we better wake up."
Funding and support for this research were provided by the Smithsonian.
========================================================================== Story Source: Materials provided by Smithsonian. Note: Content may be
edited for style and length.
========================================================================== Journal Reference:
1. W. John Kress, Gary A. Krupnick. Lords of the biosphere: Plant
winners
and losers in the Anthropocene. PLANTS, PEOPLE, PLANET, 2022;
DOI: 10.1002/ppp3.10252 ==========================================================================
Link to news story:
https://www.sciencedaily.com/releases/2022/03/220310115039.htm
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