Nebraska's Wildlife Already Feeling the Heat from Climate Change
A warmer earth is silencing the chorus of creepers, crawlers, swimmers and flyers who've inhabited the planet for millions of years
By: Carlee Koehler | July 3, 2020
As a graduate student in California, Jamilynn Poletto was part of a fish ambulance service of sorts.
Hotter weather from climate change increased water evaporation, turning flowing streams into shallow ponds. Suddenly, stranded sturgeon were in danger of overheating and at greater risk for disease, so Poletto and her colleagues rushed in with seins, nets and coolers to transport them to more hospitable waters.
Now a professor of fish physiology at the University of Nebraska-Lincoln, Poletto sees evidence that what is happening in California is happening in Nebraska too.
“There are times when we are seeing temperature spikes in rivers and in reservoirs that are unheard of,” she said. “Temperatures rise and water levels in streams drop to the point where fish become trapped.”
California has suffered from years-long drought, raging wildfires and devastating mudslides. But in Nebraska, with no shrinking glaciers or rising seas, the shifts in the natural world from climate change are not always as easy to see. The pallid sturgeon, the northern redbellied dace, and the blacknose shiner Poletto worries about live underwater, out of sight.
But, as in California, more distressed and diseased fish is just one sign that Nebraska’s environment is shifting.
Bird migration patterns are changing, invasive species are pushing out native plants and wildlife are losing habitat.
When an ecosystem changes, the losses tend to cascade. Eventually Nebraskans themselves may suffer in terms of fewer hunting, fishing and tourism opportunities. The state, which now boasts tallgrass prairie and Ponderosa pines, mountain lions and Salt Creek tiger beetles, sandhill cranes and Canada geese, may be unalterably changed in just a couple of generations by the stresses associated with climate change, according to wildlife biologists.
Nebraska has seven species endemic to the state, meaning at least 90% of the entire population exist only there. And of those seven endemic species, five of them are considered vulnerable to climate change.
“Climate changes at a rate that animals cannot evolve to or adapt to, because it’s happening so fast,” said Dennis Ferraro, a University of Nebraska-Lincoln conservation biologist and herpetologist. “They are resilient, but it’s only so much resilience they can have.”
Wildlife, of course, have lived on the margins in Nebraska for decades.
Nineteenth-century hunters tried to shoot as many buffalo as crossed their gunsights, bringing the once great herds almost to extinction.
The farm plows that followed cut through thousands of acres of rich soil, turning under habitats for burrowing owls and black-footed ferrets. City expansion and urban sprawl sliced and diced habitats even further.
Even so, the state with the most river miles among the Lower 48 supports more than 350 types of birds, tens of thousands of white-tailed and mule deer, and a rich variety of fish.
But ecosystems are already starting to shift under the stress of a warming planet.
A UNL study released in June 2019 said that ecosystems in the Great Plains have moved hundreds of miles north in the past half century, a consequence of climate change, land development and other human-related factors.
Wildfires, more frequent in a warming planet, have reduced the acreage of pines on the Pine Ridge to less than 100,000 acres from 250,000 in 1994, according to a 2014 UNL climate change report.
The Russian olive, an invasive species, is pushing out the cottonwoods in riparian forests, the UNL study said. Woody eastern red cedars are encroaching on grasslands. The coarse conifers push out native species that prefer flat open habitat like swift foxes in the process.
“Every species, every plant, every insect, amphibian and mammal are an important integral part of the ecosystem,” Ferraro said. “We lose one, the integrity of the ecosystem falls.”
Insects, for instance, time their emergence from winter to coincide with the sprouting of plants or other food sources. Pests like aphids can usually be kept in check with predators like the minute pirate bug.
But if spring starts too early, the balance is upset. More pests could survive to damage crops.
“You can get things out of sync pretty quickly,” said UNL entomology professor Tom Weissling, Ph.D.
A new study by researchers at The University of Oklahoma found grasshopper populations had fallen by 30% over two decades on a patch of preserved Kansas prairie. The study blamed the dilution of nutrients due to higher CO2 levels. Fewer grasshoppers may mean fewer pheasants, which eat the insects.
Greater concentrations of carbon dioxide levels also decrease cardenolides in milkweeds, with major consequences for the embattled monarch butterfly, Weissling said. The butterflies, which have suffered from severe population decline, are able to ingest and store the toxic steroid in their bodies as caterpillars, making them distasteful to predators and pathogens. As the insects continue to consume the milkweed plants with increased CO2 levels, they will not be getting the protection from cardenolides.
The rapid pace of seasonal change is also confusing migratory birds like snow geese that pass-through Nebraska on the Central Flyway, said Mark Vrtiska, the waterfowl program manager with Nebraska Game and Parks.
“As the days get longer [or] shorter, they’re going to be wanting to move south or north depending on what time of the year it is,” he said.
But if the day length no longer matches temperature, new chicks are in trouble. “What we’re seeing now is that they’re hatched, and the food’s not there,” Vrtiska said.
Whooping cranes migrate about 20 days earlier since the early 1940s, said Joel Jorgensen with the Nebraska Game and Parks Commission. Jorgensen said the cranes are tough birds that may be able to adapt, but other bird varieties are likely to disappear from the state.
An Audubon Society report identified the red-headed woodpecker, the piping plover and long-billed curlew as “highly vulnerable” to a warming of 3 degrees Celsius. Even moderate warming is likely to reduce the habitat range for Canada geese, the brown thrasher and the golden eagle, the report said.
The U.S. Fourth National Climate Assessment, which is written with the help of 13 federal agencies, predicted that warming temperatures and longer, more frequent droughts will reduce wetland density in the Prairie Pothole Region, which includes north central Nebraska, by as much as 25% by 2050.
Nine of Nebraska’s 12 federally endangered and threatened species use wetland areas, as do 19 of Nebraska’s 27 state-listed endangered and threatened species. Some familiar species include the river otter, bald eagle and massasauga rattlesnake.
Sarah Nevison, a biologist at Nebraska Game and Parks, is concerned over the fate of the Salt Creek tiger beetle, one of the rarest insects on the planet. The beetles only live in the salt water marshes in northern Lancaster County that are a vestige of the time when Nebraska was an inland sea.
The marshes help reduce flooding risks and protect water sources. The tiger beetle, Nevison said, serves as an indicator species— signaling that declining populations can be an early sign of trouble.
“If you don’t hunt, if you don’t look at birds, if you don’t kayak, if you do none of that, you probably like clean water,” said Nevison.
Species that are less at risk will still suffer in a warmer world.
“More than anything, the implications of climate change for Nebraska’s ecosystems should shake us from the complacency that our small network of public and private lands managed for the conservation of natural communities and wildlife will be sufficient to preserve these resources in the decades ahead,” the climate study stated.
Weather reports like in 2012, Nebraska’s hottest and driest year since 1895, could be the new average for years 2041 to 2070, according to UNL’s climate study. Droughts are thought to increase the incidence of hemorrhagic disease, which is particularly dangerous to white-tailed deer. In 2012, at least 6,000 deer died from the disease in Nebraska. The deer harvest during the 2012 November gun season fell by 25-30%, according to the Game and Parks annual report.
All of this is a threat to Nebraska’s bottom line.
Wildlife viewing brought in $722 million to Nebraska in 2016; hunting brought in more than $800 million; and fishing provided more than $300 million.
As species within an ecosystem interact, so too do the threats. Climate change is expected to cause more severe storms, which could increase the farm pollution harmful to fish and other aquatic species into streams and rivers.
Development like dams, bridges and cities in turn may limit an animal’s ability to follow their shifting habitats.
Higher CO2 levels reduce the concentration of medicine in plants that insects and animals- even humans- use.
Invasive species introduced by human activity may tolerate warmer temperatures better than native plants.
Losing species means losing the colors and chorus they provide: the rattling bugle of the sandhill crane; the howl of a coyote; the rusty brown of tallgrass prairie swaying in the fall breeze.
“I think it has to do more with our role and our responsibility as stewards. You know, with great power comes great responsibility,” said Stephen Handler, a climate change specialist with the US Forest Service. “If we have a higher vision of what humanity is all about, I think part of that vision is caring for and protecting the place we call home.”