[PCA] U.S. native crop wild relatives are diverse and threatened

[Colin Khoury]

A 5-year study examined the wild plants native to the United States that
are relatives of food and agricultural crops. The resilient plants could be
critical to feeding a planet beset by climate change. But they need to be
conserved before they disappear

Read the research article at
https://www.pnas.org/content/early/2020/12/09/2007029117

Wild cranberries have a sanctuary in West Virginia and wild peppers have a
protected area on Arizona’s border with Mexico. But many hundreds of other
crop wild relatives native to the United States – including those related
to apples, hops, grapes, pumpkins and sunflowers, to mention but a few – do
not have designated conservation areas or, even when warranted, protected
status.

The plight of America’s crop wild relatives is an overlooked subtheme in
the era of human-driven biodiversity loss. A new study in Proceedings of
the National Academy of Sciences for the first time outlines how poorly
protected these plants are: More than half of the 600 plants assessed in
the study may be endangered in their natural habitats, while only 7% are
well represented in conservation repositories such as public gene banks and
botanical gardens.

“We don’t usually think of the United States or North America as a hotspot
of globally important agricultural biodiversity, compared to regions like
the Fertile Crescent, Southeast Asia, or Mesoamerica, where so many of the
crops we grow originated,” said Colin Khoury, the study’s lead author and
researcher at the Alliance of Bioversity International and CIAT. “But our
research shows that there’s a stunning number of native plants that are, or
could be, key to the future of agriculture.”

The plants can be found across the U.S., including in Alaska, Hawaii, and
in its overseas territories, although certain regions of the continental
U.S. are particularly diverse. “We also show that previous efforts to
conserve these plants, while laudable, haven’t been sufficient to safeguard
this cultural and natural heritage,” said Khoury, who is also affiliated
with Saint Louis University and hosted at the U.S. Department of
Agriculture’s Agricultural Research Service (USDA ARS), National Laboratory
for Genetic Resources Preservation.

Wild relatives of crops are the ancestors and other closely related plant
species of the staples on our dinner tables. Having evolved to survive
climate extremes, withstand pests and diseases, and to thrive in a wide
variety of environmental conditions, these plants have characteristics that
scientists can use to breed hardier, more productive crops. Many native
species have already yielded great value, for instance, wild sunflowers,
which provide up to $400 million in annual benefits to farmers through
better resistance to pests and diseases and other traits. Others have
proved to be critical to entire agricultural sectors, such as wild native
grapes widely used as graft-stocks around the world due to their resilience
against the deadly insect pest Phylloxera.

“Continuing to find and use these traits could prove critical to food
security and the sustainability of agriculture, both here in the United
States and around the world, as climate change and natural resource
limitations such as water availability worsen,” Khoury said. “But unless we
take urgent action to better safeguard these native plants, many will
probably disappear.”

Wild plants are constantly under pressure as their natural habitats are
disturbed or destroyed, and as invasive species and climate change make
their native homes more difficult to thrive in. Many crop wild relatives,
such as wild peppers, are also harvested by people, presenting a unique
challenge for conservationists to ensure both that locals have access to
plants of cultural importance, and that the species survive for the long
term.

Wild relatives that need urgent conservation include those of cereals,
fibers, fruits, nuts, oils, pulses (such as beans), spices, sugar and
vegetable crops. Collectively, these crops are worth at least US $116
billion a year to U.S. producers, according to the USDA. Robust protection
of these plants in conservation repositories would cost a tiny fraction of
those proceeds.

Examples of crop wild relatives that are highly threatened include a
salt-tolerant sunflower native to a few locations in New Mexico and Texas,
a wild pumpkin occurring only in south-central Florida, and a wild rice
inhabiting one small stretch of the San Marcos River in Texas.

“The USDA ARS has prioritized collecting and safeguarding crop wild
relative species within the United States. Our project helps provide the
information needed to make this happen,” said Stephanie Greene, a USDA ARS
Supervisory Plant Physiologist and study co-author. “Along with
conservation practitioners in botanical gardens, land management agencies,
and other interested organizations, USDA ARS scientists will be taking
these findings forward to collect these important genetic resources.”

Field botanists wanted

The work ahead is substantial. Scientists need to collect plants in the
field, increase the capacity of conservation facilities to care for the
species for the long term, and study the plants so that information on
their potential to support agriculture is widely available. Dauntingly,
this is needed against a backdrop of declining numbers of field botanists
and other practitioners who are essential to this work.

“Reliable information is needed to minimize gaps in the conservation of
crop wild relatives, which ultimately benefit all of society,” said Anne
Frances, Lead Botanist at NatureServe and co-author of the research.
“Completing and regularly updating our understanding of which plants are at
highest risk of extinction is essential to prioritize and guide
conservation action. This study takes a giant leap towards providing this
essential information.”

Establishing new protected areas for the species, especially in rapidly
urbanizing areas of the country, will be a huge challenge. Alternatively,
taking advantage of existing protected areas and other open spaces where
the plants grow can provide easier wins. In many places, simply ensuring
land managers are aware of crop wild relatives on their lands would make
great progress toward their conservation. In some areas of the country, the
authors acknowledge, these wild plants are barely recognized, and may even
be mistaken for weeds or invasive species.

“By evaluating 600 species across the country we were able to identify
geographic hotspots of crop wild relative diversity,” said Daniel Carver of
USDA ARS and Colorado State University, and co-lead author. “We’ve compared
this information with the locations of the thousands of natural protected
areas in the U.S. to showcase where habitat conservation of these species
is currently occurring and where the gaps in protection need to be filled.”

Citizen scientists too

Protecting and making sure that these useful plants are available to
present and future generations requires not only conservation action but
also raising awareness. Hobbyists, gardeners, and nature lovers of all ages
can get in on the action. A good way to start is with a visit to one of the
countries’ hundreds of botanical gardens, which in combination boast some
120 million visitors in the U.S. during a typical year.

Botanical gardens are ramping up their efforts to inform the public about
crop wild relatives, which occur not only in the wilderness but also in
local parks, neighborhoods, and peoples’ back yards. “Botanical gardens and
other organizations interested in crop wild relatives could play a pivotal
role in introducing these plants to people, communicating their value and
plight, and better connecting the concepts of food security, agricultural
livelihoods and services provided by nature for the public,” Khoury said.

Read the research article at
https://www.pnas.org/content/early/2020/12/09/2007029117; permanent link
will be: https://doi.org/10.1073/pnas.2007029117


*Colin Khoury*

Researcher │ Biodiversity for Food and Agriculture │ Food Environment &
Consumer Behavior



*Alliance of Bioversity International and CIAT*

✉ c.khoury at cgiar.org  📱  (+1) 970 237 9571 │ Skype colin.khoury  |
pronouns he/él <https://www.mypronouns.org/what-and-why>



████████████████████████████████████████████████████████████████



The *Alliance* of *Bioversity International* and the *International Center
for Tropical Agriculture (CIAT)*
delivers research-based solutions that harness agricultural biodiversity
and sustainably transform
food systems to improve people’s lives in a climate crisis.

The *Alliance* is part of *CGIAR*, a global research partnership for a
food-secure future.

*bioversityinternational.org*
<https://www.bioversityinternational.org/>
*ciat.cgiar.org* <https://ciat.cgiar.org/>
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