Acidification Risk Assessment

This report series evaluates the relative sensitivity of NPS parks and inventory & monitoring networks to potential acidification effects caused by atmospheric nitrogen (nitrate and ammonium) and sulfur (sulfate) deposition. In terrestrial ecosystems, acidification depletes soil nutrients and mobilizes aluminum, affecting plant health and growth. In lakes and streams, acidification harms fish, amphibians, and aquatic insects.

The reports provide a relative risk assessment of acidification impacts from atmospheric nitrogen and sulfur deposition for 270 parks in 32 inventory & monitoring networks. This assessment considers three factors that influence acidification risk to park resources:

1. Nitrogen and Sulfur Pollutant Exposure
2. Ecosystem Sensitivity
3. Park Protection Mandates

National parks and networks are ranked according to each of these factors (themes). An overall risk ranking is then calculated based on averages of the three theme rankings.

Main Report

The main report provides background for the project, describes the assessment methods, and summarizes ranking results. It should be used in conjunction with each network report.

• Evaluation of the Sensitivity of Inventory and Monitoring National Parks to Acidification Effects from Atmospheric Sulfur and Nitrogen Deposition (pdf, 4.1 MB)

Inventory & Monitoring Network Reports

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Related Links

• Nitrogen Risk Assessment Report