Mussels as water cleaning ‘ecosystem engineers’


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Mussels play helpful roles in river ecosystems (via Creative Commons). 

Julia Poska | March 12, 2020

A group of citizens in Muscatine, Iowa are pushing to restore the over harvested Mississippi River mussel population. The “Mussels of Muscatine” group hopes to create learning opportunities, reverse damage to the river ecosystem and improve water quality.

The group wants to convert a dilapidated pump house into a mussel research and propagation facility, according to the Des Moines RegisterThat plan faces several logistical hurdles, but the idea that mussels could help reverse some of Iowa’s water quality degradation is valid.

CGRER member Craig Just, a University of Iowa associate professor of environmental engineering described mussel’s role as ‘ecosystem engineers’ to the Register. As the molluscs filter nutrients from the water to feed, they remove pollutants like nitrogen. Just said mussels can also remove microorganisms like algae and phytoplankton, which are harmful to ecosystems when their populations explode.

Just pointed to several challenges to restoring the Mississippi mussels as well. Iowa soil erodes into waterways at high rates, which would bury mussels and prevent them from reproducing. Mussels also must eject their larvae into fish gills, a difficult process to recreate in a lab or propagation facility.

City dwellers rejoice: spring greening comes earlier for urban plants


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The first signs of spring occur earlier in cities than surrounding rural areas, new research found (via Creative Commons).

Julia Poska | February 27, 2020

Vegetation starts turning green earlier in cities than surrounding rural areas, but urban plants are less sensitive to unseasonable warmth, new Iowa State University-led research found. The authors attribute the difference to the urban “heat island” effect.

Cities typically have somewhat higher temperatures than surrounding rural areas because materials like asphalt and brick absorb heat more readily than natural landscapes. For example, New York City is about 7 degrees Fahrenheit warmer than surrounding areas in summer, according to NASA’s Climate Kids site.

Researchers found this “heat island” phenomenon causes urban vegetation to perceive the start of spring and begin greening an average of six days earlier than surrounding rural plants.

As climate change progresses, however, plants in both rural and urban areas are responding to unseasonably warm temperatures by beginning growth earlier and earlier over time. Pollinators and last frosts have failed to keep up, which has damaged the early bloomers’ ability to survive and reproduce.

The study found that rural vegetation is more sensitive to early spring weather than urban vegetation, perhaps due to the urban heat island effect as well.

ISU Ph.D. student Ling Meng led the research team, which included CGRER member Yuyu Zhou, an ISU geological and atmospheric scientist, among others. The study, published this month in Proceedings of the National Academy of Sciences, was based on satellite images from 85 large U.S. cities from 2001 to 2014.

Zhou told the Iowa State News Service that this sort of research can help predict how plants will respond to climate change and urbanization.

EnvIowa Podcast: Talking insect ecology with Dr. Andrew Forbes


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Dr. Andrew Forbes, contributed photo.

Julia Poska | February 17, 2020

Today’s installment of the EnvIowa podcast features an interview recorded Feb. 7 with Dr. Andrew Forbes, an evolutionary ecologist at in University of Iowa biology department. Forbes chats about the ecological importance of parasitic insects and shares insights about other creepy crawlies like emerald ash borers and periodical cicadas.

Listen to learn more about his work on insect diversity and speciation.

Listen here!

 

DNR confirms further spread of deer disease through Iowa


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Deer testing positive or chronic wasting disease in Iowa since 2013, via the Iowa DNR. 

Julia Poska | February 14, 2020

Forty-three deer killed by hunters and vehicles in Iowa during the 2019-2020 hunting season tested positive for chronic wasting disease, also known as “zombie deer disease.”

This brings the total number of confirmed cases in Iowa’s wild deer population to 89 since 2013, according to an Iowa Department of Natural Resources press release. That’s a 93% increase in one year.

Chronic wasting disease is a 100% fatal neurological disease found primarily in deer and elk that causes loss of bodily functions. An abnormal protein causes the infection, spread via bodily fluids from deer to deer. Some symptoms include excessive salivation, weight loss, listlessness and drooping ears and head.

The disease is in the same family as bovine spongiform encephalopathy, also known as Mad Cow Disease. The Centers for Disease Control reports that there is no conclusive evidence of the disease transferring to humans, but the center recommends avoiding contacts with infected venison.

The Iowa DNR collected samples from about 7,000 deer hunted or killed by cars across the state during the 2019-2020 hunting season. Samples from Woodbury, Winneshiek, Fayette and Decatur counties tested positive for the first time.

Officials have identified chronic wasting disease in wild deer populations in eight counties overall. Deer in several captive populations have tested positive as well (see this interactive map for more information).

For more information on how hunters can help limit the spread of chronic wasting disease, check out this flyer.

Playboy Tortoise saves species


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Kasey Dresser| January 20, 2019

In the 1960s, giant tortoises from Espanola, a part of the Galapagos Islands, were placed on the endangered species list. In efforts to save the species, Diego, a young adult tortoise was placed into a breeding program. 15 other tortoises took part in the breeding program, but no one committed more to the cause then Diego. The species now has over 2,000 tortoises, about 1,700 of which are descendants of Diego.

Diego weighs 176 pounds and when he’s fully stretched out, stands at five feet tall. Mr. Carrion noted that there are some characteristics that made Diego “special” and more attractive to the opposite sex. As the species continue to procreate, tortoises will continue to look like Diego. A process called the bottleneck effect, where a survivor’s gene dominates the gene pool. While little genetic diversity can leave the species vulnerable to diseases or changes in habitat, Dr. Linda Cayot of the Galapagos Conservancy said that “every species came from a bottleneck.”

Last week, the zoo announced that nearing the 80th year he’s been gone, they will be retiring Diego and returning him to the Espanola islands.

“He’s contributed a large percentage to the lineage that we are returning to Espanola,” Jorge Carrion, the Galapagos National Parks service director, told AFP. “There’s a feeling of happiness to have the possibility of returning that tortoise to his natural state.”

UI research links pesticide and cardiovascular death


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Pyrethroids are commonly found in most household insecticides (via flickr). 

Julia Poska| December 30, 2019

New observational research has found that people with high exposure to common “pyrethroid” insencticides were 56% more likely to die during a study period than others. Cardiovascular disease was the leading cause of death in the exposed.

CGRER member Wei Bao, assistant professor of epidemiology in the University of Iowa College of Public Health, is an author of the study, published Jan. 30 in JAMA Internal Medicine.

Pyrethroid insecticides are used in most household insecticides and some pet products and head-lice shampoos. The study followed a sample of 2,116 adults who took the United States National Health and Nutrition Examination Survey between 1999 and 2002, representative of the U.S. population as a whole. The researchers noted levels of pyrethroid-associated chemicals in their urine and found death records to determine how many had died by 2015, as well as their cause of death.

While those with higher pyrethroid exposure were more likely to die overall, the highly exposed were three times more likely to suffer cardiovascular deaths than others as well.  Bao said in an Iowa Now feature that the study does not prove that the insecticides are the cause of death, only that death and exposure are correlated.

 

 

Chronic wasting disease confirmed in Iowa


 

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Deer (flickr/roseofredrock)

Kasey Dresser| November 25, 2019

 

Chronic wasting disease is a highly contagious disease fatal to deer, elk, and other cervids. Similar to Mad Cow, the disease is caused by an abnormal protein called a prion. A contaminated animal will show no symptoms of chronic wasting disease until around 18 months and will die shortly after showing symptoms.

On the Van Buren County Farms in Southeast Iowa, two white-tail deer were confirmed to have contracted chronic wasting disease. The Iowa Department of Agriculture is working to find the contaminant source and contain it.  The farms will be prevented from accepting deer, elk or moose for five years.

Chronic wasting disease has been confirmed in four other Iowa Counties including, Allamakee, Clayton, Dubuque, and Wayne. The disease has also been very prevalent in neighboring states, Minnesota and Wisconsin.

Hunters are encouraged to bring their deer to the Iowa Department of Natural Resources to have the animals tested for chronic wasting disease.