Approaches for estimating critical loads of N and S deposition for forest ecosystems on U.S. federal lands

Pardo, Linda H.

doi:10.2737/nrs-gtr-71

Cited by 14 publications

(16 citation statements)

References 32 publications

(35 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…There are three main approaches for estimating critical loads (Pardo 2010): empirical, steady-state mass balance (UBA 2004), and dynamic modeling (Slootweg et al 2007, de Vries et al 2010. Empirical critical loads are determined from observations of detrimental responses of an ecosystem or ecosystem component to an observed N deposition input (Pardo 2010).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Effects of nitrogen deposition and empirical nitrogen critical loads for ecoregions of the United States

Pardo

Fenn

Goodale

et al. 2011

Ecological Applications

Self Cite

398

342

View full text Add to dashboard Cite

Abstract. Human activity in the last century has led to a significant increase in nitrogen (N) emissions and atmospheric deposition. This N deposition has reached a level that has caused or is likely to cause alterations to the structure and function of many ecosystems across the United States. One approach for quantifying the deposition of pollution that would be harmful to ecosystems is the determination of critical loads. A critical load is defined as the input of a pollutant below which no detrimental ecological effects occur over the long-term according to present knowledge.The objectives of this project were to synthesize current research relating atmospheric N deposition to effects on terrestrial and freshwater ecosystems in the United States, and to estimate associated empirical N critical loads. The receptors considered included freshwater diatoms, mycorrhizal fungi, lichens, bryophytes, herbaceous plants, shrubs, and trees. Ecosystem impacts included: (1) biogeochemical responses and (2) individual species, population, and community responses. Biogeochemical responses included increased N mineralization and nitrification (and N availability for plant and microbial uptake), increased gaseous N losses (ammonia volatilization, nitric and nitrous oxide from nitrification and denitrification), and increased N leaching. Individual species, population, and community responses included increased tissue N, physiological and nutrient imbalances, increased growth, altered root : shoot ratios, increased susceptibility to secondary stresses, altered fire regime, shifts in competitive interactions and community composition, changes in species richness and other measures of biodiversity, and increases in invasive species.The range of critical loads for nutrient N reported for U.S. ecoregions, inland surface waters, and freshwater wetlands is 1-39 kg NÁha , spanning the range of N deposition observed over most of the country. The empirical critical loads for N tend to increase in the following sequence for different life forms: diatoms, lichens and bryophytes, mycorrhizal fungi, herbaceous plants and shrubs, and trees.The critical load approach is an ecosystem assessment tool with great potential to simplify complex scientific information and communicate effectively with the policy community and the public. This synthesis represents the first comprehensive assessment of empirical critical loads of N for major ecoregions across the United States.

show abstract

mentioning

confidence: 99%

“…Empirical critical loads are determined from observations of detrimental responses of an ecosystem or ecosystem component to an observed N deposition input (Pardo 2010). This level of N deposition is set as the critical load and extrapolated to other similar ecosystems.…”

mentioning

confidence: 99%

Effects of nitrogen deposition and empirical nitrogen critical loads for ecoregions of the United States

Pardo

Fenn

Goodale

et al. 2011

Ecological Applications

Self Cite

398

342

View full text Add to dashboard Cite

show abstract

“…Each is based to varying extents on observational studies or the compilation and assembly of existing data, with attempts to integrate results from both field and laboratory studies [15]. Derivation of empirical CLs is often undertaken when observational data are presumed as a response variable within an exposed system.…”

Section: Derivation Of CL Models For Nitrogen and Metalsmentioning

confidence: 99%

Atmospheric Deposition and Critical Loads for Nitrogen and Metals in Arctic Alaska: Review and Current Status

Linder¹,

Brumbaugh²,

Neitlich³

et al. 2013

OJAP

View full text Add to dashboard Cite

To protect important resources under their bureau's purview, the United States National Park Service's (NPS) Arctic Network (ARCN) has developed a series of "vital signs" that are to be periodically monitored. One of these vital signs focuses on wet and dry deposition of atmospheric chemicals and further, the establishment of critical load (CL) values (thresholds for ecological effects based on cumulative depositional loadings) for nitrogen (N), sulfur, and metals. As part of the ARCN terrestrial monitoring programs, samples of the feather moss Hylocomium splendens are being collected and analyzed as a cost-effective means to monitor atmospheric pollutant deposition in this region. Ultimately, moss data combined with refined CL values might be used to help guide future regulation of atmospheric contaminant sources potentially impacting Arctic Alaska. But first, additional long-term studies are needed to determine patterns of contaminant deposition as measured by moss biomonitors and to quantify ecosystem responses at particular loadings/ ranges of contaminants within Arctic Alaska. Herein we briefly summarize 1) current regulatory guidance related to CL values 2) derivation of CL models for N and metals, 3) use of mosses as biomonitors of atmospheric deposition and loadings, 4) preliminary analysis of vulnerabilities and risks associated with CL estimates for N, 5) preliminary analysis of existing data for characterization of CL values for N for interior Alaska and 6) implications for managers and future research needs.

show abstract

“…Th ere are three main approaches for calculating critical loads: empirical, simple mass balance, and dynamic modeling approaches (Pardo 2010). Empirical approaches are based on observations of the response of an ecosystem or ecosystem component (e.g., foliage, lichens, soil) to a given, observed deposition level.…”

Section: Critical Loads Of N Depositionmentioning

confidence: 99%

“…Empirical critical loads are determined from observations of detrimental responses of an ecosystem or ecosystem component to a given, observed N deposition input (Pardo 2010). Th is level of N deposition is set as the critical load and extrapolated to similar ecosystems.…”

Section: Critical Loads Defi Nition and Previous Usesmentioning

confidence: 99%

Assessment of Nitrogen deposition effects and empirical critical loads of Nitrogen for ecoregions of the United States

Pardo¹,

Robin-Abbott²,

Driscoll³

2011

View full text Add to dashboard Cite

Human activity in the last century has led to a substantial increase in nitrogen (N) emissions and deposition. This N deposition has reached a level that has caused or is likely to cause alterations to the structure and function of many ecosystems across the United States. One approach for quantifying the level of pollution that would be harmful to ecosystems is the critical loads approach. The critical load is defi ned as the level of a pollutant below which no detrimental ecological effect occurs over the long term according to present knowledge.The objective of this project was to synthesize current research relating atmospheric N deposition to effects on terrestrial and aquatic ecosystems in the United States and to identify empirical critical loads for atmospheric N deposition. The receptors that we evaluated included freshwater diatoms, mycorrhizal fungi and other soil microbes, lichens, herbaceous plants, shrubs, and trees. The main responses reported fell into two categories: (1) biogeochemical, and (2) individual species, population, and community responses.The range of critical loads for nutrient N reported for U.S. ecoregions, inland surface waters, and freshwater wetlands is 1 to 39 kg N ha -1 y -1. This broad range spans the range of N deposition observed over most of the country. The empirical critical loads for N tend to increase in the following sequence for different life forms: diatoms, lichens and bryophytes, mycorrhizal fungi, herbaceous plants and shrubs, trees.The critical loads approach is an ecosystem assessment tool with great potential to simplify complex scientifi c information and effectively communicate with the policy community and the public. This synthesis represents the fi rst comprehensive assessment of empirical critical loads of N for ecoregions across the United States.

show abstract

Approaches for estimating critical loads of N and S deposition for forest ecosystems on U.S. federal lands

Cited by 14 publications

References 32 publications

Effects of nitrogen deposition and empirical nitrogen critical loads for ecoregions of the United States

Effects of nitrogen deposition and empirical nitrogen critical loads for ecoregions of the United States

Atmospheric Deposition and Critical Loads for Nitrogen and Metals in Arctic Alaska: Review and Current Status

Assessment of Nitrogen deposition effects and empirical critical loads of Nitrogen for ecoregions of the United States

Contact Info

Product

Resources

About