228 



Terrestrial Ecoxysiemx — Oi(r Living Resources 



The National Park Service (NPS) Organic 

 Act and the federal Clean Air Act 

 require the NPS to protect the natural 

 resources of the lands it manages from the 

 adverse effects of air pollution. The NPS 

 established a program to measure ozone — 

 the air pollutant that is most widespread and 

 injurious to human health and vegetation — 

 at more than 40 monitoring sites within the 

 National Park System. 



NPS sites in southern and central 

 California, the Great Lakes region, and the 

 northeast and east-central United States gen- 

 erally record the highest ozone concentra- 

 tions in the NPS network. Ozone levels 

 exhibit strong seasonal and diurnal temporal 

 trends, and year-to-year variation may be 

 significant (Figure). 



The 1987-91 NPS trend in maximum 

 ozone concentrations closely resembles the 

 corresponding trend for the entire nation. 

 The National Biological Service (NBS) 

 National Air Quality Research Program 

 sponsors surveys to document ozone injury 

 to vegetation. Current monitoring concen- 

 trates on sensitive indicator plants, including 

 hardwoods and some herbaceous plants in 

 the eastern United Stales and conifers in the 

 West. Controlled fumigation studies have 

 confinned that elevated ambient ozone lev- 

 els can cause decreased growth rate, 

 decreased biomass. and premature defolia- 

 tion in sensitive species such as black cherry 



Air Quality in the 

 National Park System 



by 



Bruce Nash 



Kathy Tonnessen 



National Biological Service 



David Joseph 



Miguel Flores 



National Park Service 



(Prunits semtina), American sycamore 

 {Pkitiinus occidentcdis), yellow-poplar 

 {Liriodendron lidipifera). and ponderosa 

 pine {Piiuis ponderosa). 



Acid deposition is a regional pollutant 

 monitored at 30 NPS units as part of the 

 National Atmospheric Deposition Program 

 (NADP). Ten years of wet deposition (e.g., 

 pollutants that may come down in rain or 

 snow) data permit researchers to estimate 

 loading of nitrate, sulfate, and hydrogen ions 

 to sensitive ecosystems. NADP data show 

 that the NPS units with the greatest acid 

 loading are in the eastern United States, with 

 Acadia, Cape Cod, Shenandoah, and Great 

 Smoky Mountains national parks showing 



annual average wet deposition pH values of 

 4.4-4.6. These values do not reflect the con- 

 tributions of cloudwater, fogwater, and dry 

 deposition (e.g., particles and gases) to the 

 total loading of acids, nitrogen, and sulfate 

 to ecosystems that are sensitive to acidic 

 inputs. NADP samplers do not measure 

 snow efficiently and do not account for the 

 effect of snownielt pulses on sensitive alpine 

 lakes and streams in the spring at high-ele- 

 vation sites in the Sierra Nevada, the 

 Cascades, and the Rocky Mountains. 

 Research at Shenandoah National Park has 

 shown that deposition-driven episodes in 

 streams can result in pH levels low enough 

 to affect native fish species. 



Any assessment of ecosystem health 

 must consider the composition of the atmos- 

 phere and its interactions with the biological 

 and physical components of the ecosystem 

 under investigation. Although we have some 

 understanding of the biological effects of air 

 pollution, more studies are necessary to 

 ensure the protection of our natural 

 resources. 



For further information: 



Bruce L. Nash 



National Biological Service-AIR 



National Air Quality Research Program 



PO Box 25287 



Denver, CO 80225 



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Years (quarters/months) 

 Figure. Highest daily 1-h ozone concentration per month. 



Whitebark 

 Pine: 



Ecosystem in 

 Peril 



by 



Katherine C. Kendall 



National Biological Service 



Whitebark pine (Pimis albicaidis) is well- 

 suited to harsh conditions and populates 

 high-elevation forests in the northern Rocky 

 Mountain, North Cascade, and Sierra Nevada 

 ranges (Fig. la). Whitebark pine seeds are 

 unusually large, highly nutritious, and are a 

 preferred food for grizzly bears {Ursiis arctos) 

 and many other animals (Kendall and Amo 

 1990). These pine trees (Fig. 2) are adapted to 

 cold, dry sites and pioneer bums and other dis- 

 turbed areas. At timberline, they grow under 

 conditions tolerated by no other tree species, 



thus playing an important role in snow accu- 

 mulation and persistence. Because few roads 

 occur in whitebark pine ecosystems and 

 because the tree's wood is of little commercial 

 interest, information on the drastic decline of 

 this picturesque tree has only recently 

 emerged. 



Threats 



Whitebark pine is threatened by an intro- 

 duced disease and fire suppression. In its 



