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Pioneering naturalists, Meriwether Lewis and
William Clark eagerly accepted the opportunity to explore Thomas Jefferson's
Louisiana Purchase, a vast expanse of inland territory virtually unknown to the
European settlers of this new country.
During their 2-year, 4-month journey (1804-1806)
they and their small crew traversed the wilds of the Missouri and Yellowstone
Rivers, seeking a water route to the Pacific that never materialized. On
their way they collected and/or identified more than 170 different species
unknown to their supporters back East, a third of those found this side of the
Continental Divide. That number would have been greater had a flood not
destroyed a cache of plants at the Great Falls of the Missouri.
 Today,
the landscape Lewis and Clark explored looks much the same as it did in the
1800's. However, the mix of plant species found in some areas today varies
dramatically from those noted by the Corps of Discovery. Invasive weeds,
destructive plants that came from overseas, now crowd out native plant species
along several of the pathways traveled by Lewis and Clark.
Ag researchers, a modern-day "Corps of
Discovery," are studying ways to reverse this trend and examining new management
techniques, including biological control, to restore native plant mixes.
Leafy
Spurge is a noxious weed invading thousands of acres in the northern
Great Plains area alone. It has an extensive root system and is a prolific
seed producer making it a difficult weed to control. Leafy spurge causes
dehydration and weakness in cattle because of the toxic, milky-white latex that
is found inside of the plant. At left is a photo of two NPARL researchers
standing in a field of leafy spurge.
 Saltcedar,
also known as Tamarix, is a shrub or tree-like plant that soaks up as much as
200 gallons of water per day. Secreting salt, it forms a crust above and
below the ground, inhibiting other plant life. It averages 10-12 feet in
height, but can grow to be as tall as 20 feet. Make sure you watch out for
this plant, because as it grows it becomes a mess of thickets acting like a
wall, which are very scratchy and will tear at your clothes and skin. The
places that you are most likely to see Saltcedar is near water because it cannot
live without a lot to drink.
Purple Loosestrife is a European
ornamental from the 1800's; it prefers wetlands and edges out native plants near
waterways. Growing to an average height of 5 feet, it is noted for the
purple flowers on its spikes.
Purple loosestrife is equipped for cross
pollination and a single plant produces millions of seed which remain viable for
years. Check out the photo of purple loosestrife below. It might be
pretty, but it isn't a friendly plant to have around.
 Sulfur
Cinquefoil, another foreign invader, is identified by its sulfur yellow,
5-petal flower and palmate leaf structure. It grows an average of 3 feet
tall, and can take over areas in a wide range of environments. Animals and
wildlife find it indigestible, and believe it or not, sulfur cinquefoil is very
closely related to strawberries. So, research scientists have a hard time
coming up with a chemical or bug to help get rid of it because the chemical or
bug may also threaten strawberries.
 All
together, Lewis and Clark discovered a total of 178 plants new to
western science during their epic journey across the continent from 1804
to 1806.
Many of the plants discovered and described by Lewis and Clark proved to be new
species, and a few were new genera (for example, Lewisia and Clarkia).
Two thirds of those identified are included in a dried collection of
more than 200 specimens now housed in the
Lewis and Clark Herbarium at the Academy of Natural Science in
Philadelphia.
Lewis and Clark also discovered a total of 122
new species of mammals, fish, birds and reptiles unheard of back East, including
the antelope, coyote, western meadowlark, prairie rattler, and grizzly bear.
 Lewis
was the first to use ecological methods to describe the relations between
various western animals and their environment. Among his discoveries:
Prairie dogs never drink water.
Many animals now considered mountain denizens
actually frequented the plains when the Corps of Discovery passed by. For
example, Lewis and Clark first met the fierce grizzly bear along the Missouri
River, now the northern border of Richland County.
Except for a few memorable notes about the
abundance and virulence of the Missouri River's mosquito population, there were
only casual references to insects in Lewis and Clark's journals. However,
one tin box of insects was among the items sent from Fort Mandan to President
Jefferson.
Click on the photo to the right to see more
pictures from the NPARL dedication ceremony held on August 10, 2002. The
ceremony featured a Lewis and Clark theme both indoors and out!
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