Survey Shows Few U.P. Frogs with Deformities
by Ember Sullivan
HOUGHTON--A two-year survey conducted by middle and high school students
and teachers in western Upper Michigan suggests that amphibians here are
apparently much better off than their counterparts in other states, especially
nearby Minnesota.
Principal investigators Joan Chadde, education program coordinator for
the Center for Science and Environmental Outreach at Michigan Technological
University, and Dr. David Flaspohler of MTU's School of Forestry and Wood
Products, say samples collected in five Upper Peninsula counties showed
an incidence of frog deformities at 2 percent, compared to more than
70 percent at some Minnesota sites.
Frog deformities became a national environmental concern in 1995 when
a group of students found large numbers of deformed frogs at a pond near
Henderson, Minnesota. Since then more than 40 states have recorded deformities
in local frog populations, with the highest rates found in Minnesota and
Vermont. Wildlife specialists and environmental agencies across the country
have been trying to determine the scope of the problem and the cause of
the deformities.
Chadde and Flaspohler knew that hiring professionals or graduate students
to conduct large scale surveys would be cost-prohibitive, so they opted
instead to try to accomplish their goals with volunteers. After consulting
with experts from several states, in the spring of 1999 and again in 2000
they conducted 10-hour teacher training workshops for 6th-12th grade teachers
in western and central Upper Michigan. Education and sampling materials
were provided by the Wege Foundation and the Michigan Department of Natural
Resources Non-Game Wildlife Program. Sessions included species identification
and distribution in Michigan, an overview of frog population declines
and deformities found in other areas, why frogs are bioindicators of environmental
changes, and how to conduct frog population and deformity surveys. Workshop
participants were then asked to use their biology students to conduct
surveys at local rivers, ponds, lakes, swamps and other wetland areas
and submit their findings to the Michigan Tech team for summary and analysis.
"Over the two-year period, teachers and students from Houghton, Gogebic,
Marquette, Menominee and Ontonagon counties conducted surveys and submitted
their results," said Chadde. "We feel it was important to collect these
data so we have a baseline for future comparison in Upper Michigan. We
also wanted to show that trained volunteers, such as teachers and students,
can help professionals by monitoring a much larger area than would otherwise
have been possible, given the shortage of available professionals."
During the survey years, more than a thousand specimens were captured
from nine species of amphibians. Only two species, however, exhibited
deformities--green frogs and mink frogs. Both of these species spend more
of their life cycles in water, compared to tree frogs, which only return
to the water to reproduce in the spring. Deformities, such as deformed
limbs, missing eyes, extra limbs, and missing limbs, were found in 1.5
percent of green frogs and in 1.7 percent of mink frogs surveyed during
the two years.
"While the survey was not a rigorous scientific study, it still generated
a lot of useful information," said Flaspohler. " We had a pretty good
sample size, and it certainly showed what can be accomplished with a cadre
of trained volunteers."
As for what might be causing deformities here and elsewhere, Flaspohler
said nobody knows for certain at this point. "In Minnesota and other states,
scientists are looking at parasites, pesticides, and even solar radiation
as possible causes, but nobody has been able to pin it down as yet and
some researchers think it may be due to a combination of factors. "
Chadde, along with Dr. Tony Murphy of Hamline University (St. Paul, MN),
and Hancock (MI) High School teacher Kristan Schuster, presented a teacher-training
program titled "Frogs As Bioindicators" at last year's National Science
Teachers' Association (NSTA) convention in Orlando, FL. Their presentation
was selected for posting on the NSTA's web site: www.nsta.org/conv/sessions/biology/orl1430.asp.
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For more information, contact Joan Chadde at 906-487-3341, email: jchadde@mtu.edu;
or David Flaspohler at 906-487-3608; email: djflaspo@mtu.edu.
02/12/01-MTN010
