As you explore Denali, the raw and expansive beauty of the wilderness seems limitless. The reality, however, is that this extraordinary landscape faces formidable threats both from within its borders and beyond. In fact, in 2003, an influential park advocacy group—the National Parks Conservation Association—named Denali one of the 10 most endangered parks in the country. The sections below highlight some of the challenges faced by the park and what is being done about them.

Road Capacity Study

Maintaining a high quality experience for the greatest number of visitors while preserving park resources remains a primary challenge for park managers. In 1972 the park's visitor transportation system was implemented to manage the increased visitation resulting from the completion of the George Parks Highway. The bus system has enabled the park to keep vehicle use below the limits authorized by the 1986 General Management Plan while providing the majority of park visitors with the opportunity to travel the Park Road. With increasing visitation, some portions of the bus system are now at or near capacity, fueling requests for more buses. In 2006 the park began a series of studies to examine the impacts of traffic volume and patterns on the park road to vegetation, wildlife, physical resources, and park visitors. Researchers will use data from these studies to assess the capacity of the road, giving park managers scientific information on which to base any changes to the vehicle limits.

Development

The business and residential areas near Denali have grown tremendously in the last several years. Summer visitation in and near the park is high and an important part of the Alaska economy. Park managers have several strategies to both accommodate growth in visitation and help preserve the park's incredible resources. Mass transit within the park and in the entrance area helps reduce traffic and the need for roads and parking areas; private lodges in Kantishna generally use mass transit for their guests, as well. Backcountry use is carefully managed to maintain a wilderness experience for hikers and to conserve the landscape and wildlife. And, the National Park Service is working with the state of Alaska and others to carefully develop other visitor destinations in and adjacent to Denali National Park to spread visitor use and allow visitors more options.

Air Quality

The air in Denali National Park and Preserve is exceptionally clean, allowing spectacular views of the Alaska Range when the mountains are free of clouds. National Park Service air quality monitoring has shown that the park consistently has some of the best visibility and cleanest air measured in the country. However, airborne contaminants—some from halfway around the world—manage to find their way into the park. Each year, small but measurable amounts of pollution arrive in Denali from Europe and Asia. These pollutants come from power plants, metal smelters and other industrial sources. They are transported over the North Pole and throughout the arctic regions resulting in a phenomenon called "arctic haze." Desert dust and agricultural contaminants can reach the park by traveling directly across the Pacific Ocean. Airborne contaminants from other continents will likely increase over time as the source areas grow and develop. The park's clean air may eventually depend more on international treaties and the environmental policies of other countries than on U.S. laws designed to protect air quality.

Exotic Plants

The National Park Service defines exotic species as those occurring in a given place as a result of human action. Compared to parks in the rest of the United States, the Alaska National Park Service units are relatively pristine. Most of the exotic plants at Denali are confined to areas that have been recently or repeatedly disturbed by humans. White sweet clover has invaded naturally open riparian areas elsewhere in Alaska, but in Denali it is still confined to areas of human disturbance. Bird vetch not only invades stands of native shrubs and tree saplings, but also climbs and spreads over native plants. This plant spreads slowly and is not yet a significant problem in Denali or other parks in Alaska, but it is a threat to many parks nationwide. In fact, Denali's extreme climate and isolated location have protected the park from most exotic species. But in spite of these protective factors, the threat to parks in Alaska from exotic plants is increasing—and Denali is no exception. New exotic species are appearing, and some of those already present are spreading rapidly.

Ultraviolet Radiation

The amount of ultraviolet radiation reaching national parks is an area of special concern. Since the 1970s, the "good" ozone, positioned high in the atmosphere, has been steadily decreasing. This allows more ultraviolet radiation to reach the earth's surface, and the effects of this increased radiation are not well understood. Scientists with the National Park Service, the Environmental Protection Agency and other agencies and universities have been studying these impacts; they have found links between ultraviolet radiation exposure and skin cancer and eye disorders in humans. Ultraviolet radiation has also been linked to negative effects on amphibians, plants and aquatic ecosystems. Scientists at Denali and other parks monitor ultraviolet radiation levels on a daily basis.

Sound Quality

Many different natural sounds can be heard in Denali National Park and Preserve—the howling of wolves, the buzz of mosquitoes, the roar of rivers and the thunder of avalanches. The natural soundscape is an intrinsic element of the environment and is highly valued in Denali. An important component of the National Park Service mission is to preserve and/or restore these natural soundscapes. Because nature's hum is increasingly impacted by human-generated noise, a special soundscape program is underway. Scientists are documenting both natural and human-generated sounds at numerous locations throughout the park—including points high in the mountains, on glaciers, along rivers, in remote areas and along the main road.

Earthquakes

Denali National Park and Preserve is an area of intense seismic activity. In 2002, the park—along with most of central and southern Alaska—experienced a 7.9 magnitude earthquake, the largest ever recorded in the interior of the state. The epicenter of the earthquake was about 30 miles east of the park, on the Denali fault. Although the park area only suffered spilled shelf items and a few road sags, other areas saw profound destruction: roads were fractured, several homes were jostled off their foundations, and the Trans-Alaska oil pipeline was damaged. The park supports active research on seismic activity, and collaborates with the Alaska Earthquake Information Center and other groups to better monitor and understand earthquake potential. Three seismometers are located within the park, and efforts are underway to install portable seismometers and other instruments to measure the movement or nature of the earth's crust.

Migratory Birds

At least 80 percent of the breeding bird species in Denali are migratory—and this behavior pattern of so many species presents a complex conservation challenge to park managers. As winter comes to Denali, birds leave the park for warmer climates, heading to points south including southern Alaska, South America and the western United States. With so many birds spread over such a vast area, it is difficult to fully identify the complexity of forces that shape their long-term survival. Denali's native birds are gradually adapting to urbanization, agriculture, industry, forestry and other human activities that encroach on their habitat. In the park, increased human activities may alter habitats and habits of different species as more and more people visit Denali. Scientists are currently assessing ways to determine the abundance and distribution of birds in the park, so that they can create effective conservation strategies.