Fascinated by frogs
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By Alma Gaul | Monday, July 14, 2008 |
John Schultz/QUAD-CITY TIMES Jennifer Anderson-Cruz has spent many a Friday night at Davenport’s Nahant Marsh, counting frogs and toads as part of an ongoing 10-year study into how the amphibians respond to various changes in the environment. Buy this Photo
It’s about 10:30 on a Friday night in May as Jennifer Anderson-Cruz picks her way along the railroad tracks near Interstate 280 and Wapello Avenue in southwest Davenport.
Rocks crunch under her feet as she moves through the shadowy darkness, heading to a section of Nahant Marsh, a 513-acre wetlands within the city limits of Davenport that many lifelong residents have never heard of.
Anderson-Cruz is sure of her steps, though. She has made this trek nearly every other week from late April through mid-July, depending on the weather, over the past 10 years.
The reason: To count the number of frogs and toads in the marsh for an ongoing study of their populations and how they are affected by pollutants.
Anderson-Cruz, 32, began making her counts in 1998 when she was an undergraduate student at the former Marycrest University in Davenport. She used them as the basis of her master’s thesis submitted last year at Western Illinois University-Macomb, and she continues them today — even though she now works as a biologist in Des Moines — because she believes there is more to learn and she is passionately interested.
No calls tonight
Most people likely would be wary about trudging around in the dark, wary about what might be lurking in the tall brush or under the interstate overpass. She walks along the tracks because they go under the interstate, the only easy way she can get from one side of the marsh to the other.
Although Anderson-Cruz always takes at least one other person with her, she isn’t scared. Yes, she’s run into a few characters —- a couple of fishermen who’d had too much to drink and two motorcyclists with a pool cue and a hatchet who thought she was trespassing at Nahant — but she is intent on her work.
On this particular spring night, she stops in the darkness and listens. Her ears strain for the call of any of the six species of frogs and one species of toad commonly found in the marsh because it’s by sound that she makes her count.
She also carries her instruments for measuring air and water temperature, humidity and wind speed, and she notes whether the sky is cloudy or clear.
Calling takes a great deal of energy, “and if it gets cold or windy, they (the frogs) will shut down,” Anderson-Cruz says.
At each of seven stopping points on her route, she waits about five minutes to hear a call. If all is quiet, she moves on. A night’s work can take two hours or more. “Sometimes I don’t get out until midnight,” she says.
On this night, she hears no calls, probably because the air temperature is too cold.
Thesis looks at effects of cleanup
When Anderson-Cruz began her work 10 years ago, Nahant was still heavily polluted with lead shot and other substances left after years of shooting over the water by a sportsmen’s club. In 1999, the marsh was cleaned by the U.S. Environmental Protection Agency as a Superfund site, and the purpose of her master’s thesis was to compare the numbers of frogs and toads before and after the clean-up.
Her hypothesis was that the numbers would improve and that, in fact, is what has happened.
Her thesis also examined the effects of flooding, which she determined to be imperative to the marsh’s long-term ecological diversity.
“You need something every now and then to shake up the system,” she says.
Flooding is helpful to frogs because, on their own, they don’t travel very far. Over time, they become isolated in their own pools and breeding diversity goes down. Intermingling is healthier for them.
Anderson-Cruz is known in conservation circles statewide as a strong advocate for reptiles and amphibians, creatures that often are overlooked when managers get together to talk about habitat restoration and management.
“She is a strong initiator of our thinking about these critters,” said Doug Johnson, a soil conservationist for the Natural Resources Conservation Service in Davenport who has worked with her.
Johnson also is impressed with her willingness to work on her own time, including weekends, to do research and education.
How her interest began
Those who know Anderson-Cruz’s parents can understand where she gets her passion, spunk and love of the natural world.
Her dad is Ferrel, a retired Rock Island Arsenal chemist who is steeped in Quad-City region archaeology. Her mother is Karen, a widely known historic preservationist and a familiar face at Davenport City Hall, where she speaks out for various causes.
The Andersons took their daughter on drives along the Mississippi almost every weekend when she was little, visiting parks along the way, and they would take her camping with her grandfather at Montpelier, Iowa, during the summers.
Young Jennifer also was surrounded by adults who fed her interests: Pete Petersen, a legendary Quad-City ornithologist who introduced her to birds; Bob Bryant, the longtime naturalist at the Wapsi Environmental Education Center in Dixon, Iowa, who introduced her to plants; and her Aunt Mary, who took her places such as the Loess Hills in western Iowa.
“I was taught that nature was interesting,” Anderson-Cruz says. “And I developed a fascination with turtles, snakes, toads, frogs and salamanders. I’m not sure why.”
When she was looking for a college project and Bryant suggested a frog and toad survey at Nahant, it was a match made in heaven.
She likes her work because, in addition to being interesting, studies of various plant and animal communities can lead to their protection. “You feel like you’re making a difference,” she says.
Anderson-Cruz currently lives in Colfax, near Des Moines, where she is a biologist for the Natural Resources Conservation Service, helping private landowners with habitat restoration.
She is married to Tony (a UPS supervisor who is not very interested in frogs but very supportive of her work) and has two children, Aaron, 12, and Savanna Lindsay, who was born April 13.
Other hobbies include nature photography, hiking and gardening with native plants.
Working in nature, “I find something amazing every day, or I see something that reminds me how beautiful the world is,” she says.
“Lots of people think you need to go to the Tetons, but we have amazing things right here. They’re here and we’re losing them.”
Alma Gaul can be contacted at (563) 383-2324 or agaul@qctimes.com. Comment on this story at qctimes.com.
IF YOU GO
Jennifer Anderson-Cruz will speak about frogs beginning at 7 p.m. Friday, July 18, at Nahant Marsh in Davenport.
After her talk, anyone interested is invited to tag along as she makes her regular counts. (Wear long pants and sleeves as well as old shoes, and bring some bug spray and a flashlight.) To get there, take U.S. 61 to Iowa 22. Take Iowa 22 to Wapello Avenue and turn left onto Wapello, following it to the marsh entrance, which will be on your left.
For more on Nahant, see the story on the front page of today’s newspaper.
Why care about frogs?
2008 has been designated the “year of the frog” by the Association of Zoos and Aquariums to mark a major conservation effort to address the amphibian extinction crisis.
Although most people probably don’t give frogs much thought, they are part of the web of life, and their health is tied in with overall ecological health.
“They are kind of the canary in the coal mine,” says Jennifer Anderson-Cruz, who studies frogs at Nahant Marsh in Davenport. “If something is affecting them, then it is affecting us, too. We just don’t know it yet. They’re going to tell you in the early stages that something is wrong.”
Pragmatically, frogs are possible sources of medicines and painkillers, she says. Research indicates that skin toxins from the northern leopard frog might be able to “turn off” cancer cells, for example.
A healthy frog and toad population promotes a good natural balance in a wetlands, helping keep the mosquito population in check.
Frogs and toads also provide good food for other species such as herons; as Anderson-Cruz says, “they are a link to something somebody loves.”
Regarding the larger question of why they are declining worldwide, in addition to habitat loss, there seems to be a link with a fungus.
“This is a fungus that has been around for a while, but all of a sudden it’s become virulent,” Anderson-Cruz says. “For whatever reason, their immune systems are shutting down.”
TO LEARN MORE
Jennifer Anderson-Cruz is not alone when it comes to counting frogs. In response to the national and global decline of frogs, the Iowa Department of Natural Resources initiated in 1991 a frog and toad survey that now includes 60-70 volunteers.
n If you would like to learn more about this program and frogs in general, visit the Web site www.iowadnr.com/wildlife/diversity/frog_toad.html.
n The National Wildlife Federation maintains a FrogWatch Web site with information on frogs and toads as well as links to photos and recordings of frog calls at www.nwf.org/frogwatchUSA/.
n The U.S. Geological Survey, or USGS, also directs an amphibian and monitoring initiative. To learn more and to take a frog quiz, go to www.umesc.usgs.gov/armi.html.
n The Illinois Department of Natural Resources has information about frogs at this Web site: http://dnr.state.il.us/lands/education/spiderstudy.htm.
n On Sept. 4-6, the Midwest chapter of the Partners for Amphibian and Reptile Conservation, or PARC, will have its annual meeting at Camp Abe Lincoln, Blue Grass, Iowa. It will include a BioBlitz to do inventories of private and public lands. For more information on that, visit www.mwparc.org and www.regonline.com/MWPARC.
THE FROGS OF NAHANT
American toad (Bufo americanus)
American bullfrog (Rana catesbieana)
Northern leopard frog (Rana pipiens)
Western chorus frog (pseudacris triseriata)
Northern cricket frog (acris creptitans)
Eastern gray tree frog (Hyla versicolor)
Cope’s gray tree frog (Hyla chrysoscelis)
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