Wind Cave was established as the country's seventh national park on January 9, 1903. Many changes had occurred to the environment prior to 1900. Native animals had been driven off by hunting and settlement and the land was plowed for farming and grazed by cattle.
The cave had even been changed. Formations were removed by visitors, explorers, and guides during the 1890's with many formations being sold as souvenirs. Names were written or carved into the cave and litter was left behind. Other harmful changes were made unintentionally, some in the early days and some much later, but many happened in the effort to provide ways for visitors to see the cave.
All of these impacts affect the way we manage the park today. Today, managers treat the park as a complete system, composed of parts that are interdependent. Park managers are also looking at ways to mitigate the damage done in the past. Man-made cave openings and artificial entrances to the cave caused the cave's climate to change by allowing increased airflow through the passages. The most dramatic effect of climate change was a rock fall at the walk-in entrance caused by freezing and thawing. To help control these changes, airlocks were built at all artificial entrances to restore the cave to more natural conditions.
Electric lighting in the cave also causes problems. It increases the temperature of the cave and encourages the growth of green plants. We can control the growth of algae by turning off the cave lights when no tours are in the cave or killing it with a spray of weak chlorine bleach.
Over five million people have visited the cave since 1890. Even when everyone is careful not to touch the cave, each visitor causes changes. Everyone sheds a few clothing fibers, hair or skin cells while in the cave. This lint accumulates on cave walls and floors nearest the paved tour paths. The lint may be an unnatural food that allows molds and bacteria to grow. Approximately 100,000 people visit the cave each year and the particles from each person is small, but when multiplied by many the result is thick carpets of lint. The park relies on volunteer help to clean lint. Each year volunteers vacuum and wash parts of the cave. They even dust some sections with small paintbrushes!
One of the most serious concerns we have about the cave is what lies on the land above it. Roads, parking lots, and buildings change the direction and amount of water seeping underground. Toxic chemicals, like oils and gas leaking from vehicles and oils from the asphalt in the roadways, have washed into the cave. In the future, we hope to change the way water flows off the visitor center parking lot to prevent some of the pollution from entering the cave. We frequently check the condition of our sewage system and gasoline storage tanks to make sure there are no leaks. Pollutants seeping into the cave can harm cave life, affect crystal growth, and poison our ground water.
Changes have also been made to the lands above the cave. In the 1950's, park managers used native grass seeds to reseed areas that had once been plowed and farmed. However, 90 species of non-native plants are present in the park. These plants frequently out-compete or replace the native plants which animals need for food. Controlling these exotic plants by mowing or pulling would be almost impossible. It would be like weeding a 44 square mile garden! Using chemicals on the non-native plants might harm the cave or the groundwater. For some exotic plants, like Canada thistle, we import insects that feed only on that plant. This method is called biologic control. Any type of control on non-native plants is difficult because seeds are constantly being carried into the park by wind, birds, and mammals.
Maintaining the natural balances within the park is an ongoing challenge because of the many changes that have occurred within the natural systems. The animal community has never returned to the balance of the mid-1800's. Bison, pronghorn, and elk were all brought back to the park in the early 1900's. At first, not enough land was available for these wide-roaming animals. They had to be fed, became victims of disease, and in the case of the pronghorn, were easy targets for predators. The park's first response in 1916 was to kill hundreds of predators. When the park staff realized that grazing animals needed space to roam, to search for food and to escape predation, the wildlife did better.
But there are still no predators for the larger animals. Without the plains wolf, grizzly bear, and with only a few mountain lions in the Black Hills, bison and elk herds grow. There is a limited rangeland to support these large grazing animals. The park staff rounds-up the bison almost yearly and ships many of them to reservations and other parks.
Elk are rounded up less frequently but scientists studying elk habits are hoping to find ways to allow the elk to migrate out of the park, reducing the need for rounding-up these animals.
One of the keystone animals in the park is the prairie dog. Managing their population is important in maintaining a balance of systems within the park. They are preyed upon by eagles, hawks, owls, coyotes, bobcats, and badgers, but one of their more important predators is an endangered species. The black-footed ferret, whose diet consists mostly of prairie dogs, is missing from the ecosystem. The prairie dog colony here is barely large enough to support a population of ferrets. Ferrets would be at risk in the park because roads are dangerous barriers between sections of the prairie dog towns. To successfully bring ferrets back to Wind Cave National Park, we would have to allow the prairie dog towns to expand. This might cause some prairie dogs to move outside the park, which may not be popular with some of the park's neighbors.
Fire is a natural force that has shaped and reshaped the area's ecosystem. But, because the park is small, park managers cannot let lightning-caused fires burn unchecked. However, without frequent fires, the ponderosa pine forest would take over the grasslands and the bison, pronghorn, and prairie dogs would find their habitats shrinking. Without periodic fire, plant growth would increase the "fuels" that could cause more devastating fires. Without fire, an increasing number of ponderosa pine trees would use water that would naturally flow into streams or sink into the cave. Because fire is important in maintaining a healthy ecosystem, the park staff burns small areas of the park each year. This is called a prescribed burn. The weather conditions must be right, the wind calm and a complete crew of fire fighters must be present.
Many of the concerns we have, although seemingly unrelated, are part of a bigger picture. The relationships between animals, plants, fire, water, the cave and people are all interconnected. No one part is separate from another. Changes to one part often result in changes to another. We try to understand all parts of the park so we can protect the entire natural system that is Wind Cave National Park.