Critical Loads of Atmospheric Deposition Advances in Critical Loads in ...
National Atmospheric Deposition Program – Critical Loads of Atmospheric Deposition Advances in Critical Loads in the United States Jennifer Phelan (NADP), Jason Lynch (U.S. EPA), Claire O’Dea (U.S. FS), Tonnie Cummings (U.S. NPS), and Rick Haeuber (U.S. EPA)
Critical Load and Exceedance Maps
Background Critical Loads of Atmospheric Deposition (CLAD) is a science committee of the National Atmospheric Deposition Program (NADP) in the U.S. CLAD was officially formed in 2010, and its members consist of representatives from U.S. federal agencies, state agencies, universities, industry, non-governmental organizations, and consultants. The objectives of CLAD are to: discuss, support, and advance current and emerging issues regarding the science and use of critical loads for effects of atmospheric deposition on ecosystems in the U.S.
Presented here are three examples of critical load and exceedance maps that represent the sensitivity of aquatic and forest ecosystems and lichens to deposition in the U.S. The critical loads are from the NCLD and the exceedances were determined through comparisons of the critical loads with 3year average total N and/or S deposition from the Total Deposition (TDEP) model. TDEP is a hybrid deposition model that provides estimates of total wet and dry deposition (20002013) based on a combination of measured and modelled data. Two time periods of deposition were selected to show temporal and spatial patterns in critical load exceedances.
Recent products of CLAD include: o Definitions of critical load terms (Critical Load Definitions) o U.S. National Critical Load Database (NCLD) o Critical load maps
Critical Load Definitions CLAD produced a standard set of definitions for critical load and critical load-related terms for use by its members and interested parties in the U.S. Critical Load - A quantitative estimate of exposure to one or more pollutants below which significant harmful effects on specified sensitive elements of the environment do not occur according to present knowledge.
Tamara Blett, National Park Service
N and/or S Deposition (atmospheric pollutant)
For Aquatic Acidification, the area of exceedance was found to decrease by 47% from 2000-2002 to 2011-2013, as large reductions in S deposition occurred over this time period, mainly in the eastern U.S. However, for both Forest Ecosystem and Lichen critical loads of N, the areas of exceedance have increased by 1.5 and 28%, respectively, likely due to increased NH3 deposition throughout the U.S.
Chemical Criterion (e.g., ANC, base saturation, NO3concentration, Bc/Al ratio, change in tissue N) Chemical Threshold (e.g., (50 ueq/L of ANC, 10% base saturation, 10 ueq/L NO3-, BC/Al ratio = 1)
Biological Receptor (e.g., fish, lichen, diatoms, herbs, trees, grasslands, forest)
New Research, Products, and Future Directions
Biological Threshold (e.g., 10% decrease in growth, 5% loss of diversity, species loss)
Biological Response (e.g., death, reduced/increased growth, diversity loss, species composition change)
Figure 1. Components of critical loads
Other critical load terms: • Empirical Critical Load • Steady-state Critical Load • Target Load • Dynamic Critical Load
National Critical Load Database The CLAD National Critical Load Database (NCLD) consists of empirical and calculated critical loads data and information from many regional- and national-scale projects conducted and submitted to the NCLD by members of CLAD. This database serves as the source of data to generate critical load maps. Critical loads represented in the NCLD include: o Terrestrial Acidification o Aquatic Acidification o Empirical Critical Loads of Nitrogen (N): • Lichens • Forest Ecosystems • Herbaceous Species and Shrubs • Mycorrhizal Fungi CLAD members are encouraged to submit new data to the CLAD NCLD to share and improve the estimation, calculation, refinement, mapping, and interpretation of critical loads for U.S. ecosystems.
Contacts Dr. Jennifer Phelan Program Manager U.S. NADP-CLAD [email protected] +1-919-791-6026
Dr. Jason Lynch NADP-CLAD NCLD Manager U.S. Environmental Protection Agency (EPA) [email protected] +1-202-343-9257
For More Information… http://nadp.sws.uiuc.edu/committees/clad/
New Data to be Added to the CLAD NCLD: Tamara Blett, National Park Service
o Individual tree species responses to N deposition – Virginia Tech University. o Herb species and species richness responses to N deposition – University of Colorado. o Lichen community responses to N and S deposition – U.S. Forest Service. o Phytoplankton responses to N deposition in wilderness lakes in western U.S. – Washington State University, NPS. o Updates to terrestrial acidification critical loads – RTI International. o Updates to aquatic acr5idification critical loads – U.S. EPA, E&S Environmental Chemistry.
New and Future Critical Load Products: o Air Quality – Ecosystem Services (AQES) Framework – tool to connect biological indicators impacted by air pollution to changes in ecosystem services. o U.S. EPA Critical Load Mapper Tool – GIS web tool to examine ecosystem sensitivity to N and S deposition for the continental U.S. Includes NCLD critical loads and multiple deposition datasets ranging from 1850 to 2100. o U.S. Forest Service Handbook of Sensitive Species – three-volume technical report to identify species of lichen (vol. 1), trees (vol. 2), and herbs (vol. 3) that are sensitive to atmospheric deposition, and provide detailed descriptions of their ecology, geographic range, responses to deposition, and the ecosystem services they provide. o U.S. Forest Service Nitrogen Critical Loads Assessment by Site (NCLAS) – GIS tool for calculating and presenting empirical critical loads for forest ecosystems as a function of climatic conditions and topographic and soil characteristics.
Future Directions for CLAD: o Characterizing uncertainty of critical loads – to quantify uncertainty for critical loads in the NCLD to facilitate meaningful evaluations, comparisons, and application of critical loads. o Critical load synthesis – exploration of approaches for combining multiple critical loads for an area.
Critical Load and Exceedance Maps
Background Critical Loads of Atmospheric Deposition (CLAD) is a science committee of the National Atmospheric Deposition Program (NADP) in the U.S. CLAD was officially formed in 2010, and its members consist of representatives from U.S. federal agencies, state agencies, universities, industry, non-governmental organizations, and consultants. The objectives of CLAD are to: discuss, support, and advance current and emerging issues regarding the science and use of critical loads for effects of atmospheric deposition on ecosystems in the U.S.
Presented here are three examples of critical load and exceedance maps that represent the sensitivity of aquatic and forest ecosystems and lichens to deposition in the U.S. The critical loads are from the NCLD and the exceedances were determined through comparisons of the critical loads with 3year average total N and/or S deposition from the Total Deposition (TDEP) model. TDEP is a hybrid deposition model that provides estimates of total wet and dry deposition (20002013) based on a combination of measured and modelled data. Two time periods of deposition were selected to show temporal and spatial patterns in critical load exceedances.
Recent products of CLAD include: o Definitions of critical load terms (Critical Load Definitions) o U.S. National Critical Load Database (NCLD) o Critical load maps
Critical Load Definitions CLAD produced a standard set of definitions for critical load and critical load-related terms for use by its members and interested parties in the U.S. Critical Load - A quantitative estimate of exposure to one or more pollutants below which significant harmful effects on specified sensitive elements of the environment do not occur according to present knowledge.
Tamara Blett, National Park Service
N and/or S Deposition (atmospheric pollutant)
For Aquatic Acidification, the area of exceedance was found to decrease by 47% from 2000-2002 to 2011-2013, as large reductions in S deposition occurred over this time period, mainly in the eastern U.S. However, for both Forest Ecosystem and Lichen critical loads of N, the areas of exceedance have increased by 1.5 and 28%, respectively, likely due to increased NH3 deposition throughout the U.S.
Chemical Criterion (e.g., ANC, base saturation, NO3concentration, Bc/Al ratio, change in tissue N) Chemical Threshold (e.g., (50 ueq/L of ANC, 10% base saturation, 10 ueq/L NO3-, BC/Al ratio = 1)
Biological Receptor (e.g., fish, lichen, diatoms, herbs, trees, grasslands, forest)
New Research, Products, and Future Directions
Biological Threshold (e.g., 10% decrease in growth, 5% loss of diversity, species loss)
Biological Response (e.g., death, reduced/increased growth, diversity loss, species composition change)
Figure 1. Components of critical loads
Other critical load terms: • Empirical Critical Load • Steady-state Critical Load • Target Load • Dynamic Critical Load
National Critical Load Database The CLAD National Critical Load Database (NCLD) consists of empirical and calculated critical loads data and information from many regional- and national-scale projects conducted and submitted to the NCLD by members of CLAD. This database serves as the source of data to generate critical load maps. Critical loads represented in the NCLD include: o Terrestrial Acidification o Aquatic Acidification o Empirical Critical Loads of Nitrogen (N): • Lichens • Forest Ecosystems • Herbaceous Species and Shrubs • Mycorrhizal Fungi CLAD members are encouraged to submit new data to the CLAD NCLD to share and improve the estimation, calculation, refinement, mapping, and interpretation of critical loads for U.S. ecosystems.
Contacts Dr. Jennifer Phelan Program Manager U.S. NADP-CLAD [email protected] +1-919-791-6026
Dr. Jason Lynch NADP-CLAD NCLD Manager U.S. Environmental Protection Agency (EPA) [email protected] +1-202-343-9257
For More Information… http://nadp.sws.uiuc.edu/committees/clad/
New Data to be Added to the CLAD NCLD: Tamara Blett, National Park Service
o Individual tree species responses to N deposition – Virginia Tech University. o Herb species and species richness responses to N deposition – University of Colorado. o Lichen community responses to N and S deposition – U.S. Forest Service. o Phytoplankton responses to N deposition in wilderness lakes in western U.S. – Washington State University, NPS. o Updates to terrestrial acidification critical loads – RTI International. o Updates to aquatic acr5idification critical loads – U.S. EPA, E&S Environmental Chemistry.
New and Future Critical Load Products: o Air Quality – Ecosystem Services (AQES) Framework – tool to connect biological indicators impacted by air pollution to changes in ecosystem services. o U.S. EPA Critical Load Mapper Tool – GIS web tool to examine ecosystem sensitivity to N and S deposition for the continental U.S. Includes NCLD critical loads and multiple deposition datasets ranging from 1850 to 2100. o U.S. Forest Service Handbook of Sensitive Species – three-volume technical report to identify species of lichen (vol. 1), trees (vol. 2), and herbs (vol. 3) that are sensitive to atmospheric deposition, and provide detailed descriptions of their ecology, geographic range, responses to deposition, and the ecosystem services they provide. o U.S. Forest Service Nitrogen Critical Loads Assessment by Site (NCLAS) – GIS tool for calculating and presenting empirical critical loads for forest ecosystems as a function of climatic conditions and topographic and soil characteristics.
Future Directions for CLAD: o Characterizing uncertainty of critical loads – to quantify uncertainty for critical loads in the NCLD to facilitate meaningful evaluations, comparisons, and application of critical loads. o Critical load synthesis – exploration of approaches for combining multiple critical loads for an area.
