Badlands National Park Ecology
Spanning nearly 244,000 acres near the Black Hills in southwestern South Dakota, Badlands National Park is one of the largest expanses of a mixed-grass prairie ecosystem in the country and home to over 400 plant species. This region was named “mako sica” by the Lakota people, translating to “bad lands” because of its extreme temperatures, low amount of water, and rocky terrain. This Park is also home to the United States’ first national mammal, the American bison, which is studied and managed by the multi-agency National Bison Conservation Initiative. USGS researchers from the North Central Climate Adaptation Science Center and the Northern Prairie Wildlife Research Center recently collaborated with the National Park Service Climate Change Response Program to develop a new product that communicates the results from a collaborative effort to identify potential climate impacts and management responses in Badlands National Park.
Mixed-Grass Prairie Ecosystem
With tall-grass prairies to the east and short-grass prairies to the west, the mixed-grass prairie of Badlands National Park serves as an ecological transition zone and one of the largest protected expanses of mixed-grass prairie in the United States. Mixed-grass prairies grow in semi-arid climates. Unpredictable rainfall causes periodic floods and drought, which create short growing seasons while wildfires and thin topsoil create challenges for plants to grow. Summers in the prairie are hot and dry while winters drive blizzards. With an open landscape, winds blow across the prairie, increasing rates of evaporation. With frequent wildfires and lack of moisture, the thin topsoil of the area creates challenges for plants growing in the prairie.
Grasses thrive in Badlands National Park, along with a diverse group of plant species, trees, shrubs, and forbs (herbaceous flowering plants). Seventy-six exotic plant species have been found in the Park through plot monitoring. Japanese brome, Kentucky bluegrass, and yellow sweetclover are the most pervasive of the exotic plant species in the Park. Other rare and endemic plants in the Park include Barr’s milkvetch and Dakota buckwheat. Many species in the Park are sensitive to stressors such as invasive species, climate change, altered fire patterns, and animal grazing patterns. The most common grass in the Park is western wheatgrass, a native perennial species that can grow between one and three feet tall.
Mammals of the Mixed-Grass Prairie
Bison: The heaviest land mammal in North America, bison can grow up to 6.5 feet tall and 2,000 pounds, run up to 35 miles per hour, and have a vertical leap of up to six feet high. Bison travel nearly two miles each day, grazing and chewing the hard, dry foliage on the ground. In areas of bison grazing, plant diversity is higher than other non-grazing locations in the Park. Rolling around in the dirt, also called wallowing, is a common behavior for bison. Wallowing can relieve skin irritation and create a dirt barrier to protect their bodies against insect bites. Bison have played a key role in shaping the grasslands of the Great Plains. Bison wallows create deep depressions in the land where water collects. This collection of water supports growth of water-dependent plants and provides temporary watering holes for other vertebrates.
With an estimated pre-1800s bison population of at least 30 million across the American West, these iconic mammals dwindled to near extinction before being reintroduced to the Park in 1963. Since that time, bison have rebounded in Badlands National Park to around 1,200 individuals. The USGS is a member of the Department of the Interior Bison Working Group (BWG) along with the National Park Service, U.S. Fish and Wildlife Service, Bureau of Land Management, and the Bureau of Indian Affairs, which is working to strengthen resource coordination, institute a conservation genetics framework and publish investigations into metapopulation management and herd health.
Prairie Dogs: Black-tailed prairie dogs, the most common prairie dog species, are a keystone species of the Park, meaning that several other plants and animals rely on them for survival. They alter the landscape by digging vast, interconnected burrows which loosens soil and encourages new plant growth and eat grasses, making room for other weedy plants to grow. Although prairie dogs were widespread in the American plains before 1800, their range has decreased substantially and two of the five prairie dog species that exist today are endangered or threatened. Threats to the prairie dog population in Badlands National Park include overcrowding and wildlife disease. The sylvatic plague, also called Black Death, was brought to the United States in 1900 and continues to persist in prairie dog populations and the animals that eat them, such as black-footed ferrets, coyotes, badgers, foxes, bobcats, and rattlesnakes. To prevent outbreaks of this plague, prairie dogs in Badlands National Park are fed an oral vaccination.
Black-Footed Ferrets: These nocturnal and solitary animals reside underground in the abandoned burrows of their prey - prairie dogs. Declared as endangered in 1967 and thought to be extinct by 1980 in Badlands National Park, black-footed ferrets were reintroduced to the Park and conservation efforts are still underway for the approximately 120 black-footed ferrets who call this Park home.
Pronghorn: Pronghorn are grazing prairie animals that are often mistaken for deer or antelope, but are actually more closely related to giraffes. They feed on grasses, forbs, and shrubs that grow on the plains. Their ability to run very fast (45-55 miles per hour) allows them to use the open prairie plains to evade predators. They are smaller than deer and are found mostly living in the open grasslands of the Park.
Reptiles and Amphibians of the Mixed-Grass Prairie
Only one venomous species of snake, the prairie rattlesnake, can be found in the Park. They can grow up to five feet long and have the largest range of any other rattlesnake species in the country. They prey on burrowing owls, prairie dogs, black-footed ferrets, and other small prairie rodents. Amphibians in the Park include frogs, toads, and the blotched tiger salamander.
Birds of the Mixed-Grass Prairie
Badlands National Park lies at an aviation intersection between eastern and western lands and bird species diversity is high in the Park. Over 200 species have been documented in the Park and nearly 70 species are known to make their nests within the Park boundaries. In 2016, bird monitoring in the Park revealed that cliff swallows were the most common species of bird in the prairie. Alongside the cliff swallow, western meadowlarks, red-winged blackbirds, brown-headed cowbirds, and mourning doves are commonly found in the Park. The only non-native species of bird found during monitoring was the European starling.
Insects of the Mixed-Grass Prairie
Nearly 70 different butterfly species have been observed in Badlands National Park, including monarch butterflies, the large (five-inch wingspan) two-tailed swallowtails, hairstreaks, sulphur butterflies, and more.
Fire Use to Maintain Ecosystem
Wildfire is a natural part of grassland ecosystems and prescribed fires, controlled fires used to replicate historic cycles of natural fire occurrence, are also used by the National Park Service in Badlands National Park to reduce fuel build up and break down organic material. The breakdown of this organic material releases nutrients into the soil. Fires also help to combat invasive plant species in the Park, such as yellow sweetclover and Canada thistle. Periodic fires help to maintain the grasses in the prairie, as the dry grass tops are burned, leaving the roots unharmed.