- Air quality at Wind Cave National Park
- Related references
Air quality at Wind Cave National Park
Most visitors expect clean air and clear views in parks. Wind Cave National Park (NP), South Dakota is home to one of the world’s longest caves beneath a sea of prairie grasses in the southern Black Hills. Located in the rural Northern Great Plains the park is still affected by some nearby and regional sources of air pollution, including oil and gas production, power plants, agriculture, and vehicles. Air pollutants blown into the park can harm natural and scenic resources such as soils, surface waters, plants, wildlife, and visibility. The National Park Service works to address air pollution effects at Wind Cave NP, and in parks across the U.S., through science, policy and planning, and by doing our part.
Visitors come to Wind Cave NP to experience one of the world’s longest caves, and to enjoy views of swaying prairie grasses, forested hillsides, and an array of wildlife that includes bison, elk, and prairie dogs. Park vistas are sometimes obscured by haze, reducing how well and how far people can see. Visibility reducing haze is caused by tiny particles in the air, and these particles can also affect human health. Many of the same pollutants that ultimately fall out as nitrogen and sulfur deposition contribute to this haze. Organic compounds, soot, dust, and wood smoke reduce visibility as well. Significant improvements in park visibility have been documented since the 2000’s. Overall, visibility in the park still needs improvement to reach the Clean Air Act goal of no human caused impairment.
- Reduced visibility, at times, due to human-caused haze and fine particles of air pollution, including dust;
- Reduction of the average natural visual range from about 160 miles (without pollution) to about 115 miles because of pollution at the park;
- Reduction of the visual range to below 65 miles on high pollution days.
At ground level, ozone is harmful to human health and the environment. Ground-level ozone does not come directly from smokestacks or vehicles, but instead is formed when other pollutants, mainly nitrogen oxides and volatile organic compounds, react in the presence of sunlight.
Over the course of a growing season, ozone can damage plant tissues making it harder for plants to produce and store food. It also weakens plants making them less resistant to disease and insect infestations. Some plants are more sensitive to ozone than others. Ozone sensitive plants in the park include Apocynum androsaemifolium (spreading dogbane), Asclepias syriaca (common milkweed), and Symphoricarpos albus (common snowberry). Search for more ozone-sensitive plant species found at Wind Cave NP.
A risk assessment that considered ozone exposure, soil moisture, and sensitive plant species concluded that plants at Wind Cave NP are at low risk of ozone injury (Kohut 2004). The park’s arid to semi-arid conditions limit ozone uptake by plants. In other parks, scientists have found that plants in moist areas along streams and seeps may have higher ozone uptake and subsequent injury (Kohut et al. 2012).
Visit the NPS air quality conditions and trends website for park-specific ozone information. Wind Cave NP has been monitoring ozone since 2004. View live ozone and meteorology data and explore air monitoring »
Nitrogen and sulfur
Nitrogen and sulfur compounds deposited from the air may have harmful effects, including acidification, on soils, lakes, ponds, and streams. Some plants are sensitive to acidification, search for acid-sensitive plant species found at Wind Cave NP.
Excess nitrogen can also lead to nutrient enrichment, a process that changes nutrient cycling and alters plant communities. Plants in grassland ecosystems are often nitrogen-limited, making them vulnerable to changes caused by nitrogen deposition. Invasive grasses tend to thrive in areas with elevated nitrogen deposition, displacing native vegetation adapted to low nitrogen conditions. Cheatgrass, a non-native weed, is now common in the northern Great Plains (Ogle and Reiners 2002). Other non-native weeds at Wind Cave NP include Canada thistle, leafy spurge, and purple loosestrife. Nitrogen increases may also exacerbate water use in plants like sagebrush (Inouye 2006). Sensitive mixed-grass prairies cover about 75% of Wind Cave NP (Peterson et al. 1998). Ecosystem sensitivity to nutrient enrichment at Wind Cave NP relative to other national parks is very high (Sullivan et al. 2011a; Sullivan et al. 2011b).
Healthy ecosystems can naturally buffer a certain amount of pollution, but as nitrogen and sulfur accumulate, a threshold is passed where the ecosystem is harmed. “Critical load” is a term used to describe the amount of pollution above which harmful changes in sensitive ecosystems occur (Porter 2005). Nitrogen deposition exceeds the critical load for one or more park ecosystems (NPS ARD 2018).
Visit the NPS air quality conditions and trends website for park-specific nitrogen and sulfur deposition information. Wind Cave NP has been monitoring nitrogen and sulfur since 2003. Explore air monitoring »
Mercury and toxics
Airborne mercury, and other toxic air contaminants, when deposited are known to harm birds, salamanders, fish and other wildlife, and cause human health concerns. These substances enter the food chain and accumulate in the tissue of organisms causing reduced reproductive success, impaired growth and development, and decreased survival.
A study of mercury in precipitation from the Northern Great Plains indicated that mean mercury deposition rates at Wind Cave NP were high compared to other national parks, including nearby Badlands NP and Theodore Roosevelt NP (Stone 2011). Annual deposition rates were comparable to studies performed at similar latitudes and to estimates from the Mercury Deposition Network (MDN) (Lupo and Stone 2013).
Allen, E. B., L. E. Rao, R. J. Steers, A. Bytnerowicz, and M. E. Fenn. 2009. Impacts of atmospheric nitrogen deposition on vegetation and soils in Joshua Tree National Park. Pages 78–100 in R. H. Webb, L. F. Fenstermaker, J. S. Heaton, D. L. Hughson, E. V. McDonald, and D. M. Miller, editors. The Mojave Desert: ecosystem processes and sustainability. University of Nevada Press, Las Vegas, Nevada, USA.
Brooks, M.L. 2003. Effects of increased soil nitrogen on the dominance of alien annual plants in the Mojave Desert. Journal of Applied Ecology. 40:344–353.
Chambers, J. C., B. A. Roundy, R. R. Blank, S. E. Meyer, A. Whittaker. 2007. What Makes Great Basin Sagebrush Ecosystems Invasible by Bromus Tectorum? Ecological Monographs 77(1): 117–145.
Inouye, R.S. 2006. Effects of shrub removal and nitrogen addition on soil moisture in sagebrush steppe. Journal of Arid Environments 65: 604–618.
Kohut, B. 2004. Assessing the Risk of Foliar Injury from Ozone on Vegetation in Parks in the Northern Great Plains Network. Available at https://irma.nps.gov/DataStore/Reference/Profile/2181539.
Kohut R.J. 2007. Ozone Risk Assessment for Vital Signs Monitoring Networks, Appalachian National Scenic Trail, and Natchez Trace National Scenic Trail. NPS/NRPC/ARD/NRTR—2007/001. National Park Service. Fort Collins, Colorado. Available at https://www.nps.gov/articles/ozone-risk-assessment.htm
Kohut, B., C. Flanagan, E. Porter, J. Cheatham. 2012. Foliar Ozone Injury on Cutleaf Coneflower at Rocky Mountain National Park, Colorado. Western North American Naturalist 72(1): 32–42.
Lehmann, C. M. B., V. C. Bowersox, R. S. Larson, S. M. Larson. 2007. Monitoring Long-term Trends in Sulfate and Ammonium in US Precipitation: Results from the National Atmospheric Deposition Program/National Trends Network. Acid Rain-Deposition to Recovery: 59–66. Water Air Soil Pollut: Focus.
Lupo, C.D. and Stone, J.J. 2013. Bulk Atmospheric Mercury Fluxes for the Northern Great Plains, USA. Water, Air, & Soil Pollution 224:1437.
Mazzola, M. B., K. G. Allcock, J. C. Chambers, R. R. Blank, E. W. Schupp, P. S. Doescher, and R. S. Nowak. 2008. Effects of Nitrogen Availability and Cheatgrass Competition on the Establishment of Vavilov Siberian Wheatgrass. Rangeland Ecol Manage 61: 475–484.
National Park Service [NPS], Air Resources Division. 2010. Air quality in National Parks: 2009 Annual Performance and Progress Report. Natural Resource Report NPS/NRPC/ARD/NRR—2010/266. National Park Service, Denver, Colorado. Available at https://irma.nps.gov/DataStore/Reference/Profile/662783.
Ogle, S. M. and W. A. Reiners. 2002. A phytosociological study of exotic annual brome grasses in a mixed grass prairie/ponderosa pine forest ecotone. The American Midland Naturalist. 147(1): 25–31.
Pardo, L.H., M. J. Robin-Abbott, C. T. Driscoll, eds. 2011. Assessment of Nitrogen deposition effects and empirical critical loads of Nitrogen for ecoregions of the United States. Gen. Tech. Rep. NRS–80. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station. 291 p. Available at: http://nrs.fs.fed.us/pubs/38109.
Payne, R. J., N. B. Dise, C. J. Stevens, D. J. Gowing, et al. 2013. Impact of nitrogen deposition at the species level. PNAS 110 (3): 984–987.
Peterson, D. L., T. J. Sullivan, J. M. Eilers, S. Brace, D. Horner, K. Savig, and D. Morse. 1998. Assessment of air quality and air pollutant impacts in national parks of the Rocky Mountains and northern Great Plains. Chapter 8. Wind Cave National Park. Report NPS/CCSOUW/NRTR–98/19. National Park Service, Air Resources Division, Denver, CO. Available at https://irma.nps.gov/DataStore/Reference/Profile/11733(pdf, 583 KB).
Porter, E., Blett, T., Potter, D.U., Huber, C. 2005. Protecting resources on federal lands: Implications of critical loads for atmospheric deposition of nitrogen and sulfur. BioScience 55(7): 603–612. https://doi.org/10.1641/0006-3568(2005)055[0603:PROFLI]2.0.CO;2
Schwinning, S., B. I. Starr, N. J. Wojcik, M. E. Miller, J. E. Ehleringer, R. L. Sanford. 2005. Effects of nitrogen deposition on an arid grassland in the Colorado plateau cold desert. Rangeland Ecology and Management. 58: 565–574.
Stone, J. 2011. 2010 Project Summary Report – Assessment of Atmospheric Deposition at Select Northern Great Plains National Parks Service Locations. Unpublished report to parks, 6p.
Sullivan, T. J., McDonnell, T. C., McPherson, G. T., Mackey, S. D., Moore, D. 2011a. Evaluation of the sensitivity of inventory and monitoring national parks to nutrient enrichment effects from atmospheric nitrogen deposition: main report. Natural Resource Report NPS/NRPC/ARD/NRR—2011/313. National Park Service, Denver, Colorado. Available at https://www.nps.gov/articles/nitrogen-risk-assessment.htm
Sullivan, T. J., McDonnell, T. C., McPherson, G. T., Mackey, S. D., Moore, D. 2011b. Evaluation of the sensitivity of inventory and monitoring national parks to nutrient enrichment effects from atmospheric nitrogen deposition: Northern Great Plains Network (NGPN). Natural Resource Report NPS/NRPC/ARD/NRR—2011/330. National Park Service, Denver, Colorado. Available at https://irma.nps.gov/DataStore/Reference/Profile/2168724.
Sullivan, T. J., McPherson, G. T., McDonnell, T. C., Mackey, S. D., Moore, D. 2011c. Evaluation of the sensitivity of inventory and monitoring national parks to acidification effects from atmospheric sulfur and nitrogen deposition: main report. Natural Resource Report NPS/NRPC/ARD/NRR—2011/349. National Park Service, Denver, Colorado. Available at https://www.nps.gov/articles/acidification-risk-assessment.htm
Sullivan, T. J., McPherson, G. T., McDonnell, T. C., Mackey, S. D., Moore, D. 2011d. Evaluation of the sensitivity of inventory and monitoring national parks to acidification effects from atmospheric sulfur and nitrogen deposition: Northern Great Plains Network (NGPN). Natural Resource Report NPS/NRPC/ARD/NRR—2011/349. National Park Service, Denver, Colorado. Available at https://irma.nps.gov/DataStore/Reference/Profile/2170597.
Sullivan, T. J. and T.C. McDonnell. 2014. Mapping of nutrient-nitrogen critical loads for selected national parks in the intermountain west and great lakes regions. Natural Resource Technical Report NPS/ARD/NRTR—2014/895. National Park Service, Fort Collins, Colorado. Available at https://irma.nps.gov/DataStore/Reference/Profile/2214130.
Sullivan T.J. 2016. Air quality related values (AQRVs) in national parks: Effects from ozone; visibility reducing particles; and atmospheric deposition of acids, nutrients and toxics. Natural Resource Report. NPS/NRSS/ARD/NRR—2016/1196. National Park Service. Fort Collins, Colorado. Available at https://www.nps.gov/articles/aqrv-assessment.htm.
Vasquez, E., R. Sheley, and T. Svejcar. 2008. Nitrogen Enhances the Competitive Ability of Cheatgrass (Bromus tectorum) Relative to Native Grasses. Invasive Plant Science and Management 1 (3): 287–295.