Midwest wetlands almost gone but may still
have most species
Society for Conservation Biology
Wetlands in the Midwest? It may be hard to believe but vast
areas of today's Corn Belt used to get so wet that malaria
was common. While the remaining wetlands are small and scattered,
there's still hope -- new research shows that most of the
original species may still survive.
"We often look to other regions of the world as biodiversity
hotspots but it is worth noting that some of the most heavily
impacted regions - such as the Corn Belt - should not be
written off as biodiversity wastelands," says David Jenkins
of the University of Illinois at Springfield, who presents
this work with Scott Grissom of Grand Valley State University
in Allendale, Michigan, and Keith Miller of the University
of Illinois at Springfield in the February issue of Conservation
In the mid-1800s, much of the Corn Belt - Iowa, Illinois,
Indiana and Ohio -- was tallgrass prairie that included
extensive seasonal wetlands. For instance, ephemeral ponds
used to cover about a fifth of Illinois (nearly five million
acres) from roughly early spring to mid-summer. By the mid-1900s,
about 85% of these wetlands had been drained and converted
to agriculture, which is similar to the rate of deforestation
in tropical forests today.
To assess the biodiversity of the Midwest's remaining wetlands,
Jenkins and his colleagues studied crustaceans in 13 ephemeral
ponds near Bluff Springs, Illinois; the ponds were wide
and shallow, three feet deep at most. They chose crustaceans
because they are usually diverse and are important to these
ecosystems. The researchers sampled crustaceans from the
ponds every week during the wet seasons of three years.
Because there are no good records of the species that lived
in Illinois' wetlands historically, the researchers used
their findings to extrapolate backwards and estimate how
many crustacean species were there originally and how many
have gone locally extinct. These estimations were based
on the fact that the number of species depends on how widely
distributed they are. Jenkins and his colleagues found 33
crustacean species in the ponds they studied.
These included fairy shrimp, which are large (up to 1.5
inches), delicate and glide around on their backs; clam
shrimp, which are dark brown, the size of a pencil eraser,
and extremely active; and copepods, which are bright red
and swarm in clouds below the surface of the water.
Extrapolating backwards, the researchers estimate that there
were as many as 85 crustacean species in Illinois' seasonal
wetlands before they were drained. Similarly, the researchers
estimate that 8-9 of the original crustacean species may
have gone locally extinct.
Taken together, these findings suggest that 90% of the original
crustacean diversity may still survive in the few remaining
seasonal wetlands in Illinois. This means that despite the
huge habitat losses, there could still be time to conserve
most of the original species. "Their existence will depend
on our attention and action," says Jenkins.
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