studies climate threat to some native prairie plants
biologist Julie Etterson inspects one of the pea plants, Chamaecrista
fasciculata, that shes growing in the departments
common Great Plains prairie plant, the partridge pea (Chamaecrista
fasciculata), could face severe reduction in numbers if climate
conditions in the Midwest change to the extremes predicted for
the next 25 to 35 years, according to a study to be published
in the Oct. 5 issue of the journal Science.
the partridge pea is threatened by changing conditions, other
common native species may be threatened as well.
partridge pea's ability to adapt to rapidly changing climate conditions
is likely to be much slower than the rate of climate change predicted
for its native habitat throughout the Midwest," said the
study's principal investigator, Julie R. Etterson, a post-doctoral
research associate in biology
at the University of Virginia.
was a Ph.D. student at the University of Minnesota when she conducted
to the climate model used by Etterson for her study, Minnesota's
climate in 25 to 35 years is predicted to be similar to today's
climate in Kansas, which is drier and warmer than Minnesota's.
Under extreme conditions in a worst-case scenario, Minnesota's
climate could become more like current-day Oklahoma -- much drier
and warmer. Etterson's study indicates that native prairie plants
could be seriously threatened if these predictions hold true.
partridge pea's evolutionary response for adaptation to hotter
and drier conditions is unlikely to be fast enough to ensure its
survival," Etterson said.
Etterson planted seeds from Minnesota partridge peas in Kansas
and Oklahoma. She also planted Kansas partridge peas in Oklahoma.
She found that seed production of Minnesota plants dropped 84
percent when grown in Kansas, and 94 percent when grown in the
hotter and drier conditions of Oklahoma. The Kansas partridge
pea plants dropped 42 percent when grown in Oklahoma. She also
studied leaf number and leaf thickness, traits that are important
indicators of drought tolerance, and found that the transplants
were less adapted than local plants of the same species grown
in the same plots.
plants in the Midwest are facing two problems that may negatively
affect their future survival," Etterson said. "One,
the predicted rate of climate change is much more rapid than has
occurred previously; and two, the habitat of native plants is
fragmented to isolated islands between farms and cities, making
it difficult for plants to slowly migrate to areas with more favorable
conditions. This means plants will have to rely more on their
evolutionary response to changing conditions. The partridge pea
is unlikely to adapt to changing conditions quickly enough."
emphasizes that her findings are specific to the species she studied,
the partridge pea. "The species could possibly develop some
incremental adaptive responses to climate change during the next
25 to 35 years, but the responses are unlikely to be rapid enough.
Our findings suggest that we should not assume that plant populations
will evolve fast enough to keep pace with climate change. We
may need to think about alternative management strategies for
native species if the climate predictions prove to be accurate."