Evaluation of the Sensitivity of Inventory and Monitoring National Parks to Acidification Effects from Atmospheric Sulfur and Nitrogen Deposition. Main Report

摘要

One of the principal threats to natural resources on public lands managed by the National Park Service (NPS) is air pollution. Many air pollutants are emitted into the atmosphere outside park boundaries and are transported to the parks with the prevailing winds. Two of the most important are sulfur (S) and nitrogen (N), both of which can contribute to acidification of sensitive soil and surface water resources. Knowledge of the extent of resource sensitivity to acidic deposition is incomplete. The purpose of this assessment is to compile available information at the national scale to identify park resources that are known or thought to be sensitive to acidification from atmospheric deposition of acidifying S and N compounds. This assessment provides a first step in that process. This information will help federal land managers to assess current conditions, design monitoring programs to document and quantify changes over time, and better protect park resources. This project evaluates the sensitivity of all Inventory and Monitoring (I&M) national parks in the United States to potential acidification effects caused by acidifying atmospheric deposition. Such effects can be caused by the addition of S, oxidized N (NOx) and/or reduced N (NHx) to natural ecosystems. Acidification can occur in both terrestrial (soil and soil water) and aquatic (fresh surface water) ecosystems. The addition of S and N from air pollution sources to national park ecosystems can alter plant, animal, and algal communities at all trophic levels and influence the mix of species that thrive in those ecosystems. The response is driven by both the amount of air pollutants deposited and the sensitivity of the receptors on which the pollutants are deposited.