A meadow jumping mouse is released at Rollins Savanna Forest Preserve in Grayslake as part of a conservation program by the Lake County Forest Preserves District and the Lincoln Park Zoo. (Lake County Forest Preserves, Handout)
Scientists hope newly introduced snakes, mice and weasels will help restore the natural habitat of Lake County's open areas.
Researchers are studying, breeding and releasing these animals to increase species diversity and improve the environment in Lake County, specifically Rollins Savanna Forest Preserve in Grayslake, as part of a collaborative grassland wildlife recovery project between the Lake County Forest Preserve District and the Lincoln Park Zoo.
"Our goal is the overall preserving and increasing of the overall diversity of species," said Allison Frederick, environmental communications specialist for the Lake County Forest Preserve District. "The more balance there is, the higher quality the preserves are, in terms of ecological value."
Nine meadow jumping mice recently were released into the Rollins Savanna as part of the project, which began in 2010, and is funded by a private Lake County donor, according to Allison Sacerdote-Velat, reintroduction biologist with the Lincoln Park Zoo.
She said about $200,000 has been donated for the project so far, with more money possibly being allocated by the anonymous donor in December. The money must be used in Lake County, Sacerdote-Velat said.
The tiny mice were bred and raised in captivity at the Lincoln Park Zoo, fitted with minuscule radio transmitters and released in the former farmland turned meadow, she said. The transmitters are small collars around the mice, and do not affect any predators that might eat the mice.
The hope is to track the mice, which are able to spread seeds, and determine how and where they thrive, according to Sacerdote-Velat.
"This will be an ongoing project," she said.
This was the second release of mice within the last two months into the 1,220-acre savanna, she said, and another group will be released in the spring.
Some mice are let go immediately into the wild, according to Sacerdote-Velat, while others are introduced gradually to the habitat through a "soft release," a term coined by scientists to describe a procedure in which the mice are placed in protective pens with food for three days before being let loose.
"We can examine the effectiveness of releasing them using different techniques," Sacerdote-Velat said. "We can determine whether the habitat quality is suitable."
So far, several radio transmitters stopped working sooner than expected so researchers were unable to continue tracking, and two mice were killed by what scientists think were large non-native praying mantises, Frederick said. Though the mantis did not consume the mice, they had puncture wounds matching those made by the insect, she said.
The meadow jumping mice plan is part of a larger project to identify endangered species in the county and state, according to Frederick.
Before the mice, scientists studied smooth green snakes and Blanding's turtles, which are part of a long-term conservation project that began in 2006, said Gary Glowacki, wildlife biologist for the Lake County Forest Preserve District.
The Blanding's turtle program involves researchers collecting female turtles, monitoring the safe hatching of their young and keeping the juveniles until they are big enough to have a better chance of survival, Glowacki said, adding that diminishing wetlands have endangered the turtles' population.
"It's one of the most critically imperiled species in the state and county," Glowacki said of the turtle. "If we lost this species, it would be a big loss. They do play a significant role in our ecosystem."
Scientists also are determined to boost the population of the least weasel, though they say the cryptic creatures have proven difficult to capture.
Not only are the animals dwindling in population, but they are also critical to the area's ecosystem, scientists say.
Because of development and agriculture, smaller animals have not been able to prosper and have been forced into "habitat islands," said Sacerdote-Velat.
"Agriculture and road density has made it difficult for species to disperse," she said. "We have little populations of these species and we use those individuals for our breeding populations."
By increasing the populations of these animals, researchers hope to repopulate all the habitat islands.
"We can enhance the population and determine a good method of reintroducing these species at other reserves in the future," Frederick said.