Estimated losses of plant biodiversity in the United States from historical N deposition (1985–2010)

Clark, Christopher M.; Morefield, Philip E.; Gilliam, Frank S.; Pardo, Linda H.

doi:10.1890/12-2016.1

Cited by 72 publications

(51 citation statements)

References 28 publications

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“…Although our fire record dates back to 1980, we used the earliest available 2002 CMAQ data to provide a relative ranking of the N deposition that would be observed over our study area. CMAQ N deposition modelled data are correlated with measurements from the National Atmospheric Deposition Program (NADP) (Clark et al 2013), but this has relatively few measurement sites in the west both at present and historically. Further, dry deposition, which forms most of the deposition in arid climates, is not measured by NADP and must be inferred.…”

Section: Nitrogen Depositionmentioning

confidence: 99%

Relationships between annual plant productivity, nitrogen deposition and fire size in low-elevation California desert scrub

Rao

Matchett

Brooks

et al. 2015

Int. J. Wildland Fire

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Abstract. Although precipitation is correlated with fire size in desert ecosystems and is typically used as an indirect surrogate for fine fuel load, a direct link between fine fuel biomass and fire size has not been established. In addition, nitrogen (N) deposition can affect fire risk through its fertilisation effect on fine fuel production. In this study, we examine the relationships between fire size and precipitation, N deposition and biomass with emphasis on identifying biomass and N deposition thresholds associated with fire spreading across the landscape. We used a 28-year fire record of 582 burns from low-elevation desert scrub to evaluate the relationship of precipitation, N deposition and biomass with the distribution of fire sizes using quantile regression. We found that models using annual biomass have similar predictive ability to those using precipitation and N deposition at the lower to intermediate portions of the fire size distribution. No distinct biomass threshold was found, although within the 99th percentile of the distribution fire size increased with greater than 125 g m À2 of winter fine fuel production. The study did not produce an N deposition threshold, but did validate the value of 125 g m À2 of fine fuel for spread of fires.

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Section: Nitrogen Depositionmentioning

confidence: 99%

Relationships between annual plant productivity, nitrogen deposition and fire size in low-elevation California desert scrub

Rao

Matchett

Brooks

et al. 2015

Int. J. Wildland Fire

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“…À1 (Clark et al 2013). The critical load values were primarily determined with an N addition experiment at Cedar Creek Natural History Area, which is classified as tallgrass prairie but has a mean annual temperature of 6.78C and a mean annual precipitation of 801 mm (Clark and Tilman 2008).…”

Section: áYrmentioning

confidence: 99%

“…The concept of critical loads has been used to suggest that grasslands of the Great Plains will be experiencing significant losses of herbaceous plant diversity under current atmospheric N deposition levels (Clark et al 2013). These critical load values (5-15 kg NÁha À1 Áyr À1 ) were developed in the tallgrass prairie biome in Minnesota, which has a colder climate than Konza, but also lower ANPP than Konza due to sandy parent material and past land use history that depleted soil organic matter stocks (Knops and Tilman 2000).…”

Section: áYrmentioning

confidence: 99%

Lack of eutrophication in a tallgrass prairie ecosystem over 27 years

McLauchlan

Craine

Nippert

et al. 2014

Ecology

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Abstract. Many North American grasslands are receiving atmospheric nitrogen (N) deposition at rates above what are considered critical eutrophication thresholds. Yet, potential changes in grassland function due to anthropogenic N deposition are poorly resolved, especially considering that other dynamic factors such as land use and precipitation can also affect N availability. To better understand whether elevated N deposition has altered ecosystem structure or function in North American grasslands, we analyzed a 27-year record of ecophysiological, community, and ecosystem metrics for an annually burned Kansas tallgrass prairie. Over this time, despite increasing rates of N deposition that are within the range of critical loads for grasslands, there was no evidence of eutrophication. Plant N concentrations did not increase, soil moisture did not decline, forb diversity did not decline, and the relative abundance of dominant grasses did not shift toward more eutrophic species. Neither aboveground primary productivity nor N availability to plants increased. The fates of deposited N in grasslands are still uncertain, and could include management losses through burning and grazing. However, evidence from this grassland indicates that eutrophication of North American grassland ecosystems is not an inevitable consequence of current levels of N deposition.

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“…The primary impacts of Nr deposition appear in terrestrial and aquatic ecosystems as imbalanced nutrition (Galloway et al, 2003), decreased biological diversity (Sala et al, 2000;Stevens et al, 2004;Clark et al, 2013), eutrophication (Fenn et al, 2003;Duce et al, 2008), and acidification (Galloway et al, 2003;Sullivan et al, 2005). Each of these primary impacts lead to subsequent consequences such as disturbances in ecosystems (Galloway et al, 2003) and changes in greenhouse gas emissions and uptakes (Gruber and Galloway, 2008;Reay et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Sources of nitrogen deposition in Federal Class I areas in the US

et al. 2016

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Abstract. It is desired to control excessive reactive nitrogen (Nr) deposition due to its detrimental impact on ecosystems. Using a three-dimensional atmospheric chemical transport model, GEOS-Chem, Nr deposition in the contiguous US and eight selected Class I areas (Voyageurs (VY), Smoky Mountain (SM), Shenandoah (SD), Big Bend (BB), Rocky Mountain (RM), Grand Teton (GT), Joshua Tree (JT), and Sequoia (SQ)) is investigated. First, modeled Nr deposition is compared with National Trends Network (NTN) and Clean Air Status and Trends Network (CASTNET) deposition values. The seasonality of measured species is generally well represented by the model (R 2 > 0.6), except in JT. While modeled Nr is generally within the range of seasonal observations, large overestimates are present in sites such as SM and SD in the spring and summer (up to 0.6 kg N ha month −1 ), likely owing to model high-biases in surface HNO 3 . The contribution of non-measured species (mostly dry deposition of NH 3 ) to total modeled Nr deposition ranges from 1 to 55 %. The spatial distribution of the origin of Nr deposited in each Class I area and the contributions of individual emission sectors are estimated using the GEOS-Chem adjoint model. We find the largest role of long-range transport for VY, where 50 % (90 %) of annual Nr deposition originates within 670 (1670) km of the park. In contrast, the Nr emission footprint is most localized for SQ, where 50 % (90 %) of the deposition originates from within 130 (370) km. Emissions from California contribute to the Nr deposition in remote areas in the western US (RM, GT). Mobile NO x and livestock NH 3 are found to be the major sources of Nr deposition in all sites except BB, where contributions of NO x from lightning and soils to natural levels of Nr deposition are significant (∼ 40 %). The efficiency in terms of Nr deposition per kg emissions of NH 3 -N, NO x -N, and SO 2 -S are also estimated. Unique seasonal features are found in JT (opposing efficiency distributions for winter and summer), RM (large fluctuations in the range of effective regions), and SD (upwind NH 3 emissions hindering Nr deposition). We also evaluate the contributions of emissions to the total area of Class I regions in critical load exceedance, and to the total magnitude of exceedance. We find that while it is effective to control emissions in the western US to reduce the area of regions in CL exceedance, it can be more effective to control emissions in the eastern US to reduce the magnitude of Nr deposition above the CL. Finally, uncertainty in the nitrogen deposition caused by uncertainty in the NH 3 emission inventory is explored by comparing results based on two different NH 3 inventories; noticeable differences in the emission inventories and thus sensitivities of up to a factor of four found in individual locations.

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Estimated losses of plant biodiversity in the United States from historical N deposition (1985–2010)

Cited by 72 publications

References 28 publications

Relationships between annual plant productivity, nitrogen deposition and fire size in low-elevation California desert scrub

Relationships between annual plant productivity, nitrogen deposition and fire size in low-elevation California desert scrub

Lack of eutrophication in a tallgrass prairie ecosystem over 27 years

Sources of nitrogen deposition in Federal Class I areas in the US

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