Air Quality at Badlands National Park
Most visitors expect clean air and clear views in parks. Badlands National Park (NP), South Dakota, is a rugged landscape of spires, canyons, fossils, prairie, and roaming bison that has relatively good air quality due in part to the rural setting of the surrounding Northern Great Plains. However, there are some nearby and regional sources of air pollution, including oil and gas production, power plants, agriculture, and vehicles. These air pollutants can harm the park’s natural and scenic resources such as soils, surface waters, vegetation, and visibility. The National Park Service works to address air pollution effects at Badlands NP, and in parks across the U.S., through science, policy and planning, and by doing our part.
Nitrogen and Sulfur
Nitrogen (N) and sulfur (S) compounds deposited from the air may have harmful effects on ecosystem processes. Healthy ecosystems can naturally buffer a certain amount of pollution, but once a threshold is passed the ecosystem may respond negatively. This threshold is the critical load, or the amount of pollution above which harmful changes in sensitive ecosystems occur (Porter 2005). N and S deposition change ecosystems through eutrophication (N deposition) and acidification (N + S deposition). Eutrophication increases soil and water nutrients which causes some species to grow more quickly and changes community composition. Ecosystem sensitivity to nutrient N enrichment at Badlands National Park (BADL) relative to other national parks is high (Sullivan et al. 2016); for a full list of N sensitive ecosystem components, see: NPS ARD 2019. Acidification leaches important cations from soils, lakes, ponds, and streams which decreases habitat quality. Ecosystem sensitivity to acidification at BADL relative to other national parks is moderate (Sullivan et al. 2016); to search for acid-sensitive plant species, see: NPSpecies.
From 2017-2019 total N deposition in BADL ranged from 5.2 to 6.0 kg-N ha-1 yr-1 and total S deposition ranged from 0.9 to 1.1 kg-S ha-1 yr-1 based on the TDep model (NADP, 2018). See the conditions and trends website for park-specific information on N and S deposition at BADL.
Arid ecosystems have shown variable responses to excess N. Badlands sparse vegetation at BADL, a community that supports plant species adapted to low fertility conditions, has critical loads ranging from 4 to 6 kg-N ha-1 yr-1 (Symstad et al 2019). Invasive grasses tend to thrive in areas with elevated N deposition, displacing native vegetation adapted to low N conditions. Cheatgrass—a non-native weed—is a “common invader” in the northern Great Plains (Ogle and Reiners 2002). In similar ecoregions of the southern Colorado Plateau, Great Basin, and Mojave Desert, increased N deposition has allowed weedy annual grasses (e.g., cheatgrass) to invade grasslands at the expense of native species (Brooks 2003; Schwinning et al. 2005; Chambers et al. 2007; Mazzola et al. 2008; Vasquez et al. 2008; Allen et al. 2009). N increases may also exacerbate water use in plants like big sagebrush (Inouye 2006). Potential increases in N emissions and deposition in the region, including from oil and gas exploration and production, place native plant communities at higher risk for harmful effects.
Acidification risk at BADL is low in part because surface waters and soils are well buffered against acid inputs.
Epiphytic macrolichen community responses
Epiphytic macrolichens grow on tree trunks, branches, and boles. Since these lichens grow above the ground, they obtain all their nutrients directly from precipitation and the air. Many epiphytic lichen species have narrow environmental niches and are extremely sensitive to changes in air pollution. Epiphytic lichen communities are less diverse in arid areas, but are still impacted by air pollution. Geiser et al. (2019) used a U.S. Forest Service national survey to develop critical loads of nitrogen (N) and critical loads of sulfur (S) to prevent more than a 20% decline in four lichen community metrics: total species richness, pollution sensitive species richness, forage lichen abundance, and cyanolichen abundance.
McCoy et al. (2021) used forested area from the National Land Cover Database to estimate the impact of air pollution on epiphytic lichen communities. Forested area makes up 3.1 km2 (0.32%) of the land area of Badlands National Park.
- N deposition exceeded the 3.1 kg-N ha-1 yr-1 critical load to protect N-sensitive lichen species richness in 100% of the forested area.
- S deposition was below the 2.7 kg-S ha-1 yr-1 critical load to protect S-sensitive lichen species richness in every part of the forested area.
For exceedances of other lichen metrics and the predicted decline of lichen communities see Appendices A and B of McCoy et al. (2021).
Additional modeling was done on 459 lichen species to test the combined effects of air pollution and climate gradients (Geiser et al. 2021). A critical load indicative of initial shifts from pollution-sensitive toward pollution-tolerant species occurred at 1.5 kg-N ha-1 yr-1 and 2.7 kg-S ha-1 yr-1 even under changing climate regimes.
Plant species response
Plants vary in their tolerance of eutrophication and acidification, and some plant species respond to nitrogen (N) or sulfur (S) pollution with declines in growth, survival, or abundance on the landscape. Horn et al. (2018) used the U.S. Forest Service national forest survey to develop critical loads of N and critical loads of S to prevent declines in growth or survival of sensitive tree species. Clark et al. (2019) used a database of plant community surveys to develop critical loads of N and critical loads of S to prevent a decline in abundance of sensitive herbaceous plant species. According to NPSpecies, Badlands National Park contains:
- 5 N-sensitive tree species and 24 N-sensitive herbaceous species.
- 7 S-sensitive tree species and 22 S-sensitive herbaceous species.
Many visitors come to Joshua Tree NP to enjoy the spectacular vistas, including that of the Mexican border from the mile-high vantage point of Keys View. Unfortunately, park vistas are often 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.
- Reduced visibility on many days due to haze
- Reduction of the average natural visual range from about 160 miles (without the effects of pollution) to about 100 miles because of pollution at the park
- Reduction of the visual range from about 120 miles to below 55 miles on high pollution days
Visit the NPS air quality conditions and trends website for park-specific visibility information. Joshua Tree NP has been monitoring visibility since 2000. Check out the live air quality webcam and explore air monitoring »
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. Joshua Tree NP experiences high ozone concentrations, with peak levels and cumulative doses that are some of the highest in the NPS.
Especially during the summer months, ozone levels in the park frequently exceed the National Ambient Air Quality Standards set by the U.S. Environmental Protection Agency to protect public health. Ozone is a respiratory irritant, causing coughing, sinus inflammation, chest pains, scratchy throat, lung damage, and reduced immune system functions. Children, the elderly, people with existing health problems, and active adults are most vulnerable. When ozone levels exceed, or are predicted to exceed, health standards, Joshua Tree NP staff post health advisories cautioning visitors of the potential health risks associated with exposures to elevated levels.
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. While the generally dry conditions in the park are likely to limit ozone uptake by plants, a wet year or strong summer monsoon season may increase the risk of ozone injury. There are a few ozone-sensitive plants in the park including Salix gooddingii (Goodding’s willow). Limited assessments in the park have not documented ozone injury to vegetation growing naturally in the field (Temple 1989); however, no assessment has been made of other ozone effects such as growth effects. A study of Rhus trilobata conducted in a park biomonitoring plot demonstrated that under irrigated conditions the plants showed typical ozone injury symptoms (Temple 1989), demonstrating that ozone levels are sufficiently high in Joshua Tree NP to damage plant leaves, and possibly reduced growth effects, under certain conditions (Sullivan et al. 2001). Search ozone-sensitive plant species found at Joshua Tree NP.
Visit the NPS air quality conditions and trends website for park-specific ozone information. Joshua Tree NP has been monitoring ozone since 1993. Check out the live ozone and meteorology data from Joshua Tree NP and explore air monitoring »
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.
Clark, C.M., Simkin, S.M., Allen, E.B. et al. Potential vulnerability of 348 herbaceous species to atmospheric deposition of nitrogen and sulfur in the United States. Nat. Plants 5, 697–705 (2019). https://doi.org/10.1038/s41477-019-0442-8
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.
Geiser, Linda & Nelson, Peter & Jovan, Sarah & Root, Heather & Clark, Christopher. (2019). Assessing Ecological Risks from Atmospheric Deposition of Nitrogen and Sulfur to US Forests Using Epiphytic Macrolichens. Diversity. 11. 87. 10.3390/d11060087.
Geiser, Linda & Root, Heather & Smith, Robert & Jovan, Sarah & Clair, Larry & Dillman, Karen. (2021). Lichen-based critical loads for deposition of nitrogen and sulfur in US forests. Environmental Pollution. 291. 118187. 10.1016/j.envpol.2021.118187.
Horn KJ, Thomas RQ, Clark CM, Pardo LH, Fenn ME, Lawrence GB, et al. (2018) Growth and survival relationships of 71 tree species with nitrogen and sulfur deposition across the conterminous U.S.. PLoS ONE 13(10): e0205296. https://doi.org/10.1371/journal.pone.0205296
Inouye, R.S. 2006. Effects of shrub removal and nitrogen addition on soil moisture in sagebrush steppe. Journal of Arid Environments. 65: 604–618.
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.
McCoy K., M. D. Bell, and E. Felker-Quinn. 2021. Risk to epiphytic lichen communities in NPS units from atmospheric nitrogen and sulfur pollution: Changes in critical load exceedances from 2001‒2016. Natural Resource Report NPS/NRSS/ARD/NRR—2021/2299. National Park Service, Fort Collins, Colorado. https://doi.org/10.36967/nrr-2287254.
[NADP] National Atmospheric Deposition Program. 2018. NTN Data. Accessed January 20, 2022. Available at http://nadp.slh.wisc.edu/NADP/
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.
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.
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, CO.
Symstad, A. J., A. T. Smith, W. E. Newton, and A. K. Knapp. 2019. Experimentally derived nitrogen critical loads for northern Great Plains vegetation. Ecological Applications 29:e01915.
Vasquez E., Sheley R., and Svejcar T. "Nitrogen Enhances the Competitive Ability of Cheatgrass (Bromus tectorum) Relative to Native Grasses," Invasive Plant Science and Management 1(3), 287-295, (1 July 2008). https://doi.org/10.1614/IPSM-08-062.1