2008 Science Delivery Highlights
Research Maps Ecosystem Overload
Numerous research studies have shown that nitrogen, sulfur, and ozone pollutants reduce forest growth, degrade soils, damage lake and stream water quality, alter biodiversity, and increase forest mortality. Despite this knowledge and significant investments to reduce or mitigate negative pollution effects, policymakers and regulators have no easy means to judge the sensitivity of U.S. ecosystems to important air pollutants. Critical load, defined as the level of a pollutant above which an ecosystem experiences detrimental effects, is a metric that can be used for this purpose.
Researchers with the Eastern Forest Environmental Threat Assessment Center developed a national map of critical pollutant loads for nitrogen and sulfur, following the leads of Canada and European nations. Previous critical load mapping studies do not account for the combined influence of multiple pollutants (e.g., nitrogen and ozone) or the impact of non-critical load stresses (e.g., drought, insect, or disease) on forest ecosystem health. A systematic assessment of coarse scale national level and fine scale special interest area critical load projections was completed in this five phase study plan.
The results, titled “Estimates of critical acid loads and exceedances for forest soils across the conterminous United States” in Environmental Pollution, have been useful to Forest Service research work units, federal scientists, university staff and faculty, and interested individuals and organizations in the private sector.
Contact: Steve McNulty, Southern Global Change Program team leader, (919) 515-9489, smcnulty@fs.fed.us
Partners: U.S. Forest Service, Southern Research Station; E&S Environmental
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Photo by Robert L. Anderson, USDA Forest Service, www.bugwood.org
