Skip to Main Content
Using epiphytic macrolichen communities for biomonitoring ammonia in forests of the greater Sierra Nevada, CaliforniaAuthor(s): Sarah Jovan; Bruce Mccune
Source: Water, Air, and Soil Pollution. 170(1-4): 69-93
Publication Series: Scientific Journal (JRNL)
Station: Pacific Northwest Research Station
View PDF (1.05 MB)
DescriptionChronic, excessive nitrogen deposition is potentially an important ecological threat to forests of the greater Sierra Nevada in California. We developed a model for ammonia bioindication, a major nitrogen pollutant in the region, using epiphytic macrolichens. We used non-metric multidimensional scaling to extract gradients in lichen community composition from surveys at 115 forested sites. A strong ammonia deposition gradient was detected, as evidenced by a high linear correlation with an index of ammonia indicator species conventionally known as "nitrophytes" (r = 0.93). This gradient, however, was confounded by elevation (r = -0.54). We evaluated three statistical techniques for controlling the influence of elevation on nitrophytes: simple linear regression, nonlinear regression, and nonparametric regression. We used the unstandardized residuals from nonlinear regression to estimate relative ammonia deposition at each plot, primarily because this model had the best fit (r2 = 0.33), desirable asymptotic properties, and it is easy to apply to new data. Other possible sources of noise in the nitrophyte-ammonia relationship, such as substrate pH and acidic deposition, are discussed. Lichen communities indicated relatively high deposition to forests of the southern Sierra Nevada, the Modoc Plateau, as well as in stands near urban areas. Evidence of elevated ammonia was also detected for popular recreation areas such as Sequoia and Yosemite National Parks. Lichen communities from forests in the Tahoe basin, northern Sierra Nevada, southern Cascades, and eastern Klamath Range appeared considerably less impacted. This model will be used for continual assessment of eutrophication risks to forest health in the region.
- You may send email to email@example.com to request a hard copy of this publication.
- (Please specify exactly which publication you are requesting and your mailing address.)
- We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
CitationJovan, Sarah; Mccune, Bruce. 2006. Using epiphytic macrolichen communities for biomonitoring ammonia in forests of the greater Sierra Nevada, California. Water, Air, and Soil Pollution. 170(1-4): 69-93.
Keywordsair pollution, ammonia, California, epiphytic lichens, forest health, gradients, indicator species, National Parks, nitric acid, nitrophytes, non-metric multidimensional scaling, Sierra Nevada
- Air-quality bioindication in the greater central valley of California, with epiphytic macrolichen communities.
- Atmospheric chemistry
- Nitrogen content of Letharia vulpina tissue from forests of the Sierra Nevada, California: geographic patterns and relationships to ammonia estimates and climate
XML: View XML