How Does Nature Cope with Wisconsin's Unnaturally Warm Weather

Feb 21, 2017

People have been shedding their winter layers over the last few days, as spring-like temperatures have settled in Wisconsin. We’re used to meteorologists talking about occasional record high and low temperatures – but long stretches like this are less common.

WUWM Environmental Reporter Susan Bence headed about 30 miles northwest to learn what scientists are observing at the UW-Milwaukee field station. It is plunked strategically where three natural areas converge – beech maple forest, a wetland and an acidic black spruce bog.

“With an amazing diversity of plants and animals and all in relatively pristine condition,” says field station director Jim Reinartz.

He’s been here since the early 1980s.

Reinartz calls our current stretch of warm weather – a false spring. And in his quiet way, Reinartz worries about what it might leave in its wake.

“They have always occurred, but they seem to becoming more common. 2007 and 2012 and again this looks like it’s developing into full-blown false spring. The problem with weather like this is it is especially hard on woody plants – where they’ll break buds and start to flower and we know we can’t count on it staying warm now,” he says.

Reinartz tugs down a delicate branch of a nannyberry bush.

“It’s a great example of how pretty much all the woody plants that bloom early in the spring have their flowers completely formed already in the bud – they’re formed in the fall – so there’s the entire nannyberry flower head just compacted in the bud – and you can see how delicate the tissue is and you can imagine how hard it must be physiologically to keep that living flower bud tissue alive over a winter.” He adds, “That’s why it’s so vulnerable to change, to freezing after that.

Reinartz says while only researchers might wonder about the fate of the nannyberry blossom, agriculture is also tied to the weather. He recalls the toll warm temps took on Wisconsin fruit tree farmers, not long ago.

"It can and has completely wiped out fruit crops because they will flower early and then those flowers are killed by a frost after that. This could be another one of those years."

“In 2012, we had just unbelievably warm weather – I think it got into the 80s if I recall and then after that we got a lot of cold weather…. we can still count on some pretty good hard freezes after this weather and this can be really damaging to plants from an agriculture perspective,” Reinartz says.

Naturalist Kate Redmond has tramped these wetlands and forests for decades. She identifies the birdsong around her.

“The nuthatch and cardinals we’re hearing are winter residents,” she says.  Yet Redmond says magnificent migrating cranes are moving through earlier than usual.

Credit Kate Redmond

“Some of the larger birds like the cranes and the waterfowl, they will typically follow the edge of the ice north and weather is certainly a stimulus for that migrating earlier. And it’s been warm south of here too, so they think it’s time for them to go. And I’m not sure that the cranes are going to find something to eat in another week because it’s going to be getting colder.” Redmond adds, “The other thing that they eat are fresh shoots of vegetation that are coming up and there aren’t going to be any of those in the foreseeable future.”

Both Redmond and Jim Reinartz hold more than a little concern about extreme swings in weather that jar ecosystems – sometimes from top to bottom.

While Reinartz maintains a professional demeanor, naturalist Redmond is a free agent. She hopes what she calls the latest symptom of climate change causes more people to reflect.

“I think everybody who puts on a t-shirt should enjoy themselves and feel guilty at the same time,” Redmond says.