Ecosystem nutrient responses to chronic nitrogen inputs at Fernow Experimental Forest, West Virginia

Gilliam, Frank S.; Adams, Mary Beth; Yurish, Bradley M.

doi:10.1139/x26-023

Cited by 113 publications

(46 citation statements)

References 29 publications

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“…For example, the Watershed Acidification Study at Fernow Experimental Forest, West Virginia, added 35 kg NÁha , which has led to changes in understory species composition . Recently, similar changes in understory species composition have occurred on the adjacent reference watershed receiving only ambient atmospheric deposition (Gilliam et al 1996;F. S. Gilliam, unpublished data) suggesting that the deposition to the reference watershed currently exceeds the critical load.…”

Section: Fig 4 Map Of (A) Critical Loads (Cl) and (B) Exceedances Omentioning

confidence: 75%

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

Pardo

Fenn

Goodale

et al. 2011

Ecological Applications

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398

342

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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.

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Section: Fig 4 Map Of (A) Critical Loads (Cl) and (B) Exceedances Omentioning

confidence: 75%

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

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“…Several previous studies (Stoddard 1994;Gilliam et al 1996;Peterjohn et al 1996) concluded that, in addition to WS3, which is the N-fertilized watershed, other watersheds at FEF are experiencing increasing levels of N saturation because of high levels of ambient atmospheric deposition. In comparison with our results, Gilliam et al (2001) …”

Section: Soil Nmentioning

confidence: 99%

“…Ecosystem-level responses to N saturation have been well documented (e.g., Tamm et al 1995;Gilliam et al 1996;Peterjohn et al 1996;Edwards et al 2002;Fernandez et al 2003), but there has been little study of the effects of excessive N deposition on internal plant nutrient dynamics or the potential for plants to modify those effects through variation in the disposition and use efficiency of individual nutrients.…”

Section: Introductionmentioning

confidence: 99%

Interspecific divergence in foliar nutrient dynamics and stem growth in a temperate forest in response to chronic nitrogen inputs

May¹,

Burdette²,

Gilliam³

et al. 2005

Can. J. For. Res.

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Abstract:We studied the effects of excessive nitrogen (N) fertilization on foliar nutrient dynamics and stem growth in three important tree species in a mixed-deciduous forest. Stem diameter growth, foliar N concentrations, nitrogenphosphorus (N/P) ratios, and nutrient resorption were determined for Acer rubrum L. (ACRU), Liriodendron tulipifera L. (LITU), and Prunus serotina Ehrh. (PRSE) on two 30-year-old watersheds at the Fernow Experimental Forest, West Virginia, USA: WS3, fertilized annually with 35 kg ammonium sulfate·ha -1 since 1989, and WS7, an untreated control watershed. In an earlier (1992) study, foliar N concentrations of all three species averaged 11% higher in WS3 than in WS7. By 2000, that was no longer the case for any species; indeed N in ACRU leaves was 13% lower in WS3 that year. N/P ratios were elevated in WS3 only in PRSE in 1992 and in both ACRU and PRSE in 1997, but by 2001, mean N/P for all three species was lower in WS3. N resorption efficiencies were 30% lower in WS3 in ACRU and PRSE, but not in LITU. Stem diameter growth in WS3 was 55% lower in ACRU and 30% lower in LITU and PRSE compared with that in WS7. Results may indicate declining growth vigor in ACRU and, to a lesser extent, PRSE and LITU in the fertilized watershed. Observed interspecific differences in growth and plant nutrition responses suggest eventual changes in species composition under increasing N saturation.

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“…Eastern hardwood forest regions with higher levels of N deposition (US EPA 2002; Experimental N additions indicate broadly similar responses to the gradient studies above ( (Gilliam et al 1996), and decreased tree growth by some species but not others (May et al 2005, DeWalle et al 2006. Th ese results resemble those from fertilization experiments at an oak stand at Millbrook, New York (Wallace et al 2007), and at a red pine stand and an oak-maple stand at Harvard Forest, Massachusetts (Table 10.1; Bowden et al 2004, Frey et al 2004, Magill et al 2000, Magill et al 2004, Minocha et al 2000, Venterea et al 2004.…”

Section: Range Of Responses Observedmentioning

confidence: 53%

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

Pardo¹,

Robin-Abbott²,

Driscoll³

2011

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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

Ecosystem nutrient responses to chronic nitrogen inputs at Fernow Experimental Forest, West Virginia

Cited by 113 publications

References 29 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

Interspecific divergence in foliar nutrient dynamics and stem growth in a temperate forest in response to chronic nitrogen inputs

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

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