Bighorn sheep on grassland in Yellowstone National Park, Wyoming. Joel Berger , CC BY-ND

In the grip of winter, the North American prairies can look deceptively barren. But many wild animals have evolved through harsh winters on these open grasslands, foraging in the snow and sheltering in dens from cold temperatures and biting winds.

Today most of our nation’s prairies are covered with the amber waves of grain that Katharine Lee Bates lauded in “America the Beautiful,” written in 1895. But scientists know surprisingly little about today’s remnant biodiversity in the grasslands – especially the status of what we call “big small mammals,” such as badgers, foxes, jackrabbits and porcupines.

Land conservation in the heartland has been underwhelming. According to most estimates, less than 4% of the tallgrass prairie ecosystem that once covered some 170 million acres of North America is left. And when native grasslands are altered, populations of endemic species like prairie dogs shrink dramatically.

Together, we have more than 60 years of experience using field-based, hypothesis-driven science to conserve wildlife in grassland systems in North America and across the globe. We have studied and protected species ranging from pronghorn and bison in North America to saiga and wild yak in Central Asia. If scientists can identify what has been lost and retained here in the U.S., farmers, ranchers and communities can make more informed choices about managing their lands and the species that depend upon them.

Two harsh centuries of settlement

North America’s prairies stretch north from Mexico into Canada, and from the Mississippi River west to the Rocky Mountains. Grasslands also exist in areas farther west, between the Rockies and Pacific coastal ranges.

When Thomas Jefferson approved the Lewis and Clark Expedition in 1803, this territory was home to Native Americans and abundant wildlife. Vast, unbroken horizons of contiguous grasslands supported millions of prairie dogs, pronghorn, bison and elk, and thousands of bighorn sheep. Birds were also numerous, including greater prairie-chickens, multiple types of grouse and more than 3 billion passenger pigeons.

Lewis and Clark kept detailed records of the plants and animals they encountered on their three-year journey. Their journals describe grizzly bears and wolves, black-footed ferrets and burrowing owls, sage grouse and prairie chickens. Sources like this and John James Audubon’s “Birds of America,” published between 1827 and 1838, confirm that before European settlement, North America’s prairies teemed with wildlife.

That changed as European immigrants moved west over the next hundred years. Market hunting was one cause, but settlers also tilled and poisoned, fertilized and fenced the land, drained aquifers and damaged soils.

As humans altered the prairies, bison disappeared from 99% of their native range. Prairie dogs, black-footed ferrets, wolves and grizzly bears followed the same sad course.

In the mid-20th century, conservationists began fighting to protect and restore what remained. It isn’t surprising that wildlife agencies and conservation organizations focused on targets that were big, famous and economically important: Birds for hunting, deer for dinner and fisheries for food and sport.

Some efforts succeeded. Montana has retained every species that Lewis and Clark observed there. In 2016 Congress passed legislation declaring bison the U.S. national mammal, following various restoration initiatives in places such as the Wichita Mountains of Oklahoma and the Tallgrass Prairie Preserve in the Flint Hills of Kansas.

Pronghorn antelope, which Lewis and Clark called “speed goats,” have rebounded from fewer than 20,000 in the early 20th century to some 700,000 today, ranging across grasslands from northern Mexico and Texas to North Dakota, Montana and southern Canada.