As ecologist, environmental ethicist and Wisconsin resident Aldo Leopold observed, we’re part of an intricate web of life. But that web is under stress from climate change, impacting the life cycles of Wisconsin wildlife.
To learn more about the effects of warming winters on Wisconsin fauna, WUWM's environmental reporter Susan Bence spoke to Gary Casper, director of biodiversity programs at Mequon Nature Preserve.
Casper has worked on ecological restoration projects and biodiversity studies throughout the Midwest, and he’s been monitoring all sorts of wildlife in Wisconsin for decades.
He’s worried about the impacts of climate change and erratic winter weather on the mammals, reptiles, amphibians and other inhabitants of the 510-acre nature preserve.
“We’re right on a transition zone from southern prairie to northern forest, so there’s a lot of species that are kind of at the edge of their range limits here and they’re all going to be affected as this climate changes,” Casper says.
The preserve is in the process of restoring prairie, forest and wetland habitats. Marshy, wetland areas serve as natural sponges and appeal to some of the critters Casper is keeping an eye on.
“They’re breeding hubs for amphibians, and we also have other special creatures that are dependent upon these hydric soils that have been restored — the prairie crayfish,” Casper explains.
Casper says others take advantage of the pathways as well. “Especially the snakes, and some insects and frog and salamanders — to get down to the groundwater during drought periods and escape the heat,” he says.
Although climate change leads to warmer winters overall, it also leads to abrupt spikes and volatile temperature changes that can affect these burrowing creatures.
"If there’s a deep freeze, it can reach their underground retreats and they might not survive and that’s true for many amphibians here as well,” Casper says.
Further north in Wisconsin, UW-Madison researchers including wildlife ecologist Dr. Jonathan Pauli have been keeping an eye on a small mammal trying to safely navigate warmer winters with less snow cover.
Pauli says the white backdrop of snow cover is critical for the snowshoe hare — named for its large, snowshoe-shaped hind feet. The hares are brown much of the year, but they turn white in the winter. The snow provides camouflage to protect them from predators.
But as winters have progressively become warmer and snow cover has diminished, “these snowshoe hares were still white,” Pauli says. “They were highly vulnerable to predation because their white snowshoe hares on a brown background.”
Yet the snowshoe hare’s fate might not be as bleak as it sounds, and Pauli says that effective forest management can reduce the hare’s vulnerability.
Closer to home in Waukesha County, efforts are underway to protect delicate ephemeral pond habitats threatened by climate change. Home to frogs and other amphibians like the blue-spotted salamander, ephemeral ponds form in shallow ground depressions from spring precipitation and snow melts.
As snow begins to melt, frogs and salamanders migrate from the forest to ephemeral ponds to lay eggs as spring begins.
“When we have warmer winters, which usually means early spring, that rhythm is off,” says biologist and Waukesha County Parks’ Natural Resource Program Coordinator Julia Robson.
The fate of wetlands systems matters for other wildlife too — not just amphibians.
“Seventy five percent of wildlife in Wisconsin depend on wetlands at one point of their life or another,” she says.
Take the nesting yellow warbler, which feeds off of wetland insects, that hatch in ephemeral ponds each year. "They’re eating insects primarily," Robson says. "These ephemeral wetlands will be the first areas that start producing early hatches and emergence of insects, so these wetlands are also providing really critical food for other wildlife."
