Empirical and simulated critical loads for nitrogen deposition in California mixed conifer forests

Fenn, Mark E.; Jovan, Sarah; Yuan, Fengming; Geiser, Linda H.; Meixner, Thomas; Gimeno, B.S.

doi:10.1016/j.envpol.2008.03.019

Cited by 122 publications

(111 citation statements)

References 67 publications

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“…Other studies reported no change in total species richness as the work performed in Italian grassland with N addition of 35 kg ha −1 yr −1 (Bonanomi et al, 2006). However, the effects of N dep and [NH 3 ] atm are much clearer when measures of functional groups instead of total diversity are used (Fenn et al, 2008), which is in accordance to what was observed in this work. The relation between LDVs and N dep and LDVs and [NH 3 ] atm was highly significant (P < 0.0001), both N dep and [NH 3 ] atm presenting the same type of relationship to lichen functional groups: higher N dep and [NH 3 ] atm led to a decrease of oligotrophic species (LDVoligo) and to an increase of nitrophytic ones (LDVnitro) (Figs.…”

Section: Critical Load Of Nitrogen Deposition and Critical Level Of Asupporting

confidence: 82%

“…The establishment of CLOs for N dep has used several strategies, being most commonly based on empirical work, although a modelling approach has also been used (Fenn et al, 2008). The establishment of CLEs for ammonia has been mostly grounded on empirical work (Bobbink et al, 2011;Fenn et al, 2008), quantifying the effect of increasing [NH 3 ] atm on a receptor (Cape et al, 2009).…”

Section: P Pinho Et Al: Critical Loads Of Nitrogen Deposition and Cmentioning

confidence: 99%

“…In fact, due to lichens dependence on atmospheric nutrition, lichens respond directly to atmospheric pollution, making them ideal to establish thresholds of airborne N. Lichens have frequently been used to assess the effects of industrial pollution (Augusto et al, 2009;Branquinho et al, 2008;Giordani, 2007;Pinho et al, 2004) providing spatially explicit information on the effects of those pollutants (Pinho et al, 2008a, b). For both CLOs and CLEs, lichen communities have been used as one of the most sensitive receptors; recent proposal for revision of CLEs was mainly based on alterations in lichen communities (Cape et al, 2009;Fenn et al, 2008) and the most recent CLOs established for a large number of ecosystems were also based on lichens (Bobbink et al, 2011). Specifically regarding the effects of N red , a successful strategy was the use of lichen functional response groups (Lavorel and Garnier, 2002), i.e.…”

Section: P Pinho Et Al: Critical Loads Of Nitrogen Deposition and Cmentioning

confidence: 99%

“…The establishment of CLEs for ammonia has been mostly grounded on empirical work (Bobbink et al, 2011;Fenn et al, 2008), quantifying the effect of increasing [NH 3 ] atm on a receptor (Cape et al, 2009). In fact, due to lichens dependence on atmospheric nutrition, lichens respond directly to atmospheric pollution, making them ideal to establish thresholds of airborne N. Lichens have frequently been used to assess the effects of industrial pollution (Augusto et al, 2009;Branquinho et al, 2008;Giordani, 2007;Pinho et al, 2004) providing spatially explicit information on the effects of those pollutants (Pinho et al, 2008a, b).…”

Section: P Pinho Et Al: Critical Loads Of Nitrogen Deposition and Cmentioning

confidence: 99%

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Critical loads of nitrogen deposition and critical levels of atmospheric ammonia for semi-natural Mediterranean evergreen woodlands

et al. 2012

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Abstract. Nitrogen (N) has emerged in recent years as a key factor associated with global changes, with impacts on biodiversity, ecosystems functioning and human health. In order to ameliorate the effects of excessive N, safety thresholds such as critical loads (deposition fluxes) and levels (concentrations) can be established. Few studies have assessed these thresholds for semi-natural Mediterranean ecosystems. Our objective was therefore to determine the critical loads of N deposition and long-term critical levels of atmospheric ammonia for semi-natural Mediterranean evergreen woodlands. We have considered changes in epiphytic lichen communities, one of the most sensitive comunity indicators of excessive N in the atmosphere. Based on a classification of lichen species according to their tolerance to N we grouped species into response functional groups, which we used as a tool to determine the critical loads and levels. This was done for a Mediterranean climate in evergreen cork-oak woodlands, based on the relation between lichen functional diversity and modelled N deposition for critical loads and measured annual atmospheric ammonia concentrations for critical levels, evaluated downwind from a reduced N source (a cattle barn). Modelling the highly significant relationship between lichen functional groups and annual atmospheric ammonia concentration showed the critical level to be below 1.9 µg m −3 , in agreement with recent studies for other ecosystems. Modelling the highly significant relationship between lichen functional groups and N deposition showed that the critical load was lower than 26 kg (N) ha −1 yr −1 , which is within the upper range established for other semi-natural ecosystems. Taking into account the high sensitivity of lichen communities to excessive N, these values should aid development of policies to protect Mediterranean woodlands from the initial effects of excessive N.

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Section: Critical Load Of Nitrogen Deposition and Critical Level Of Asupporting

confidence: 82%

Section: P Pinho Et Al: Critical Loads Of Nitrogen Deposition and Cmentioning

confidence: 99%

Section: P Pinho Et Al: Critical Loads Of Nitrogen Deposition and Cmentioning

confidence: 99%

Section: P Pinho Et Al: Critical Loads Of Nitrogen Deposition and Cmentioning

confidence: 99%

See 2 more Smart Citations

Critical loads of nitrogen deposition and critical levels of atmospheric ammonia for semi-natural Mediterranean evergreen woodlands

et al. 2012

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“…The tolerance level of lichens to nitrogen was utilised in recent years to assess the critical load of several forest ecosystems (e.g. Fenn et al 2008). In accordance with the publication by Geiser et al (2010), the critical load for lichens in coniferous forests of the northwest United States ranges between 0.7 and 4.4 kg·ha·yr -1 , depending on the rainfall.…”

Section: Discussionmentioning

confidence: 99%

Ground vegetation as an important factor in the biodiversity of forest ecosystems and its evaluation in regard to nitrogen deposition

Buriánek¹,

Novotný²,

Hellebrandová³

et al. 2013

J. For. Sci.

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ABSTRACT:We documented the current typological and phytosociological characterisation of the ground vegetation as an essential component of biodiversity in 154 Czech forest monitoring plots and to describe its changes during the past 15 years in regard to the deposition and concentration of nitrogen in the soil. Plots were classified as vegetation units in accordance with the UNECE and FAO nomenclature and on the basis of their potential natural vegetation and compared in terms of the occurrence and coverage of the indicative selected nitrophilous species. In all the soil horizons tested statistically significant differences in the C/N ratio were observed between areas with and without the presence of certain selected nitrophilous species (Geranium robertianum, Impatiens parviflora, Sambucus nigra, Urtica dioica). In the areas with the presence of the Geranium robertianum and Urtica dioica species, statistically significantly higher concentrations of nitrogen were recorded in some soil horizons than in those areas with the absence of these species. The findings concerning the influence of nitrogen on nitrophilous herbaceous indicators were compared with the European results obtained in the framework of the ICP Forests international programme and with those of other foreign studies.

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Drivers of atmospheric nitrate processing and export in forested catchments

Rose

Sebestyen

Elliott

et al. 2015

Water Resources Research

104

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Increased deposition of reactive atmospheric N has resulted in the nitrogen saturation of many forested catchments worldwide. Isotope-based studies from multiple forest sites report low proportions (mean 5 10%) of unprocessed atmospheric nitrate in streams during baseflow, regardless of N deposition or nitrate export rates. Given similar proportions of atmospheric nitrate in baseflow across a variety of sites and forest types, it is important to address the postdepositional drivers and processes that affect atmospheric nitrate transport and fate within catchments. In a meta-analysis of stable isotope-based studies, we examined the influence of methodological, biological, and hydrologic drivers on the export of atmospheric nitrate from forests. The d values tended to increase with increasing baseflow discharge at all sites examined. To explain these differences, we present a conceptual model of hydrologic flowpath characteristics (e.g., saturation overland flow versus subsurface stormflow) that considers the influence of topography on landscape-stream hydrologic connectivity and delivery of unprocessed atmospheric nitrate to streams. Methodological biases resulting from differences in sampling frequency and stable isotope analytical techniques may further influence the perceived degree of unprocessed atmospheric nitrate export. Synthesis of results from numerous isotope-based studies shows that small proportions of unprocessed atmospheric nitrate are common in baseflow. However, hydrologic, topographic, and methodological factors are important drivers of actual or perceived elevated contributions of unprocessed atmospheric nitrate to streams.

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Empirical and simulated critical loads for nitrogen deposition in California mixed conifer forests

Cited by 122 publications

References 67 publications

Critical loads of nitrogen deposition and critical levels of atmospheric ammonia for semi-natural Mediterranean evergreen woodlands

Critical loads of nitrogen deposition and critical levels of atmospheric ammonia for semi-natural Mediterranean evergreen woodlands

Ground vegetation as an important factor in the biodiversity of forest ecosystems and its evaluation in regard to nitrogen deposition

Drivers of atmospheric nitrate processing and export in forested catchments

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