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Journal ArticleDOI

Global assessment of nitrogen deposition effects on terrestrial plant diversity: a synthesis.

TL;DR: Ecosystems thought of as not N limited, such as tropical and subtropical systems, may be more vulnerable in the regeneration phase, in situations where heterogeneity in N availability is reduced by atmospheric N deposition, on sandy soils, or in montane areas.
Abstract: Atmospheric nitrogen (N) deposition is a recognized threat to plant diversity in temperate and northern parts of Europe and North America. This paper assesses evidence from field experiments for N deposition effects and thresholds for terrestrial plant diversity protection across a latitudinal range of main categories of ecosystems, from arctic and boreal systems to tropical forests. Current thinking on the mechanisms of N deposition effects on plant diversity, the global distribution of G200 ecoregions, and current and future (2030) estimates of atmospheric N-deposition rates are then used to identify the risks to plant diversity in all major ecosystem types now and in the future. This synthesis paper clearly shows that N accumulation is the main driver of changes to species composition across the whole range of different ecosystem types by driving the competitive interactions that lead to composition change and/or making conditions unfavorable for some species. Other effects such as direct toxicity of nitrogen gases and aerosols, long-term negative effects of increased ammonium and ammonia availability, soil-mediated effects of acidification, and secondary stress and disturbance are more ecosystem- and site-specific and often play a supporting role. N deposition effects in mediterranean ecosystems have now been identified, leading to a first estimate of an effect threshold. Importantly, ecosystems thought of as not N limited, such as tropical and subtropical systems, may be more vulnerable in the regeneration phase, in situations where heterogeneity in N availability is reduced by atmospheric N deposition, on sandy soils, or in montane areas. Critical loads are effect thresholds for N deposition, and the critical load concept has helped European governments make progress toward reducing N loads on sensitive ecosystems. More needs to be done in Europe and North America, especially for the more sensitive ecosystem types, including several ecosystems of high conservation importance. The results of this assessment show that the vulnerable regions outside Europe and North America which have not received enough attention are ecoregions in eastern and southern Asia (China, India), an important part of the mediterranean ecoregion (California, southern Europe), and in the coming decades several subtropical and tropical parts of Latin America and Africa. Reductions in plant diversity by increased atmospheric N deposition may be more widespread than first thought, and more targeted studies are required in low background areas, especially in the G200 ecoregions.

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Citations
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Journal ArticleDOI
TL;DR: Food in the Anthropocene : the EAT-Lancet Commission on healthy diets from sustainable food systems focuses on meat, fish, vegetables and fruit as sources of protein.

4,710 citations

Journal ArticleDOI
TL;DR: In the ocean, the lifetime of Nr is less well known but seems to be longer than in terrestrial ecosystems and may represent an important long-term source of N2O that will respond very slowly to control measures on the sources of NR from which it is produced.
Abstract: Global nitrogen fixation contributes 413 Tg of reactive nitrogen (Nr) to terrestrial and marine ecosystems annually of which anthropogenic activities are responsible for half, 210 Tg N. The majority of the transformations of anthropogenic Nr are on land (240 Tg N yr−1) within soils and vegetation where reduced Nr contributes most of the input through the use of fertilizer nitrogen in agriculture. Leakages from the use of fertilizer Nr contribute to nitrate (NO3−) in drainage waters from agricultural land and emissions of trace Nr compounds to the atmosphere. Emissions, mainly of ammonia (NH3) from land together with combustion related emissions of nitrogen oxides (NOx), contribute 100 Tg N yr−1 to the atmosphere, which are transported between countries and processed within the atmosphere, generating secondary pollutants, including ozone and other photochemical oxidants and aerosols, especially ammonium nitrate (NH4NO3) and ammonium sulfate (NH4)2SO4. Leaching and riverine transport of NO3 contribute 40–70 Tg N yr−1 to coastal waters and the open ocean, which together with the 30 Tg input to oceans from atmospheric deposition combine with marine biological nitrogen fixation (140 Tg N yr−1) to double the ocean processing of Nr. Some of the marine Nr is buried in sediments, the remainder being denitrified back to the atmosphere as N2 or N2O. The marine processing is of a similar magnitude to that in terrestrial soils and vegetation, but has a larger fraction of natural origin. The lifetime of Nr in the atmosphere, with the exception of N2O, is only a few weeks, while in terrestrial ecosystems, with the exception of peatlands (where it can be 102–103 years), the lifetime is a few decades. In the ocean, the lifetime of Nr is less well known but seems to be longer than in terrestrial ecosystems and may represent an important long-term source of N2O that will respond very slowly to control measures on the sources of Nr from which it is produced.

1,330 citations

Journal ArticleDOI
TL;DR: It is shown that limited phosphorus and nitrogen availability are likely to jointly reduce future carbon storage by natural ecosystems during this century and if phosphorus fertilizers cannot be made increasingly accessible, the crop yields projections of the Millennium Ecosystem Assessment imply an increase of the nutrient deficit in developing regions.
Abstract: Bioavailable nitrogen is increasing due to human activity, rapidly outpacing increases in another essential nutrient, phosphorous. Penuelas et al. show that this increasing imbalance between these nutrients is likely to significantly affect life and limit carbon storage in this century.

959 citations

Journal ArticleDOI
TL;DR: If the lowest loss and waste percentages achieved in any region in each step of the FSC could be reached globally, food supply losses could be halved and there would be enough food for approximately one billion extra people.

943 citations


Cites background from "Global assessment of nitrogen depos..."

  • ...Moreover, the use of synthetic fertilisers has negative impacts on biodiversity and water quality (Bobbink et al., 2010; Galloway et al., 2008; Gruber and Galloway, 2008; Smil, 2002)....

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BookDOI
01 Oct 2012
TL;DR: The Global Energy Assessment (GEA) as mentioned in this paper brings together over 300 international researchers to provide an independent, scientifically based, integrated and policy-relevant analysis of current and emerging energy issues and options.
Abstract: The Global Energy Assessment (GEA) brings together over 300 international researchers to provide an independent, scientifically based, integrated and policy-relevant analysis of current and emerging energy issues and options. It has been peer-reviewed anonymously by an additional 200 international experts. The GEA assesses the major global challenges for sustainable development and their linkages to energy; the technologies and resources available for providing energy services; future energy systems that address the major challenges; and the policies and other measures that are needed to realize transformational change toward sustainable energy futures. The GEA goes beyond existing studies on energy issues by presenting a comprehensive and integrated analysis of energy chalenges, opportunities and strategies, for developing, industrialized and emerging economies. This volume is a invaluable resource for energy specialists and technologists in all sectors (academia, industry and government) as well as policymakers, development economists and practitioners in international organizations and national governments.

812 citations

References
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Journal ArticleDOI
10 Mar 2000-Science
TL;DR: This study identified a ranking of the importance of drivers of change, aranking of the biomes with respect to expected changes, and the major sources of uncertainties in projections of future biodiversity change.
Abstract: Scenarios of changes in biodiversity for the year 2100 can now be developed based on scenarios of changes in atmospheric carbon dioxide, climate, vegetation, and land use and the known sensitivity of biodiversity to these changes. This study identified a ranking of the importance of drivers of change, a ranking of the biomes with respect to expected changes, and the major sources of uncertainties. For terrestrial ecosystems, land-use change probably will have the largest effect, followed by climate change, nitrogen deposition, biotic exchange, and elevated carbon dioxide concentration. For freshwater ecosystems, biotic exchange is much more important. Mediterranean climate and grassland ecosystems likely will experience the greatest proportional change in biodiversity because of the substantial influence of all drivers of biodiversity change. Northern temperate ecosystems are estimated to experience the least biodiversity change because major land-use change has already occurred. Plausible changes in biodiversity in other biomes depend on interactions among the causes of biodiversity change. These interactions represent one of the largest uncertainties in projections of future biodiversity change.

8,401 citations


"Global assessment of nitrogen depos..." refers background in this paper

  • ...…global scale, current N emission scenarios project that most regions will have increased rates of atmospheric N deposition in 2030 (Dentener et al. 2006), which is causing concern about significant impacts on global plant biodiversity (Vitousek et al. 1997, Sala et al. 2000, Phoenix et al. 2006)....

    [...]

  • ...In general, the potential risk of global impacts of N enrichment on biodiversity have been recognized (e.g., Sala et al. 2000, Phoenix et al. 2006), but there has been no attempt to compile the evidence across major global biomes of the effects of N deposition on plant diversity....

    [...]

  • ...…deposition poses to plant diversity around the globe using assessment procedures based to various extents on the critical-loads approach (e.g., Bouwman et al. 2002, Dentener et al. 2006, Phoenix et al. 2006) and scenario studies considering all major drivers of biodiversity loss (Sala et al. 2000)....

    [...]

  • ...N deposition effects in mediterranean ecosystems have now been identified, leading to a first estimate of an effect threshold....

    [...]

  • ...—Increased ammonium availability can be toxic to sensitive plant species, especially in habitats with nitrate as the dominant N form and originally hardly any ammonium....

    [...]

Journal ArticleDOI
TL;DR: In this article, a review of available scientific evidence shows that human alterations of the nitrogen cycle have approximately doubled the rate of nitrogen input into the terrestrial nitrogen cycle, with these rates still increasing; increased concentrations of the potent greenhouse gas N 2O globally, and increased concentration of other oxides of nitrogen that drive the formation of photochemical smog over large regions of Earth.
Abstract: Nitrogen is a key element controlling the species composition, diversity, dynamics, and functioning of many terrestrial, freshwater, and marine ecosystems. Many of the original plant species living in these ecosystems are adapted to, and function optimally in, soils and solutions with low levels of available nitrogen. The growth and dynamics of herbivore populations, and ultimately those of their predators, also are affected by N. Agriculture, combustion of fossil fuels, and other human activities have altered the global cycle of N substantially, generally increasing both the availability and the mobility of N over large regions of Earth. The mobility of N means that while most deliberate applications of N occur locally, their influence spreads regionally and even globally. Moreover, many of the mobile forms of N themselves have environmental consequences. Although most nitrogen inputs serve human needs such as agricultural production, their environmental conse- quences are serious and long term. Based on our review of available scientific evidence, we are certain that human alterations of the nitrogen cycle have: 1) approximately doubled the rate of nitrogen input into the terrestrial nitrogen cycle, with these rates still increasing; 2) increased concentrations of the potent greenhouse gas N 2O globally, and increased concentrations of other oxides of nitrogen that drive the formation of photochemical smog over large regions of Earth; 3) caused losses of soil nutrients, such as calcium and potassium, that are essential for the long-term maintenance of soil fertility; 4) contributed substantially to the acidification of soils, streams, and lakes in several regions; and 5) greatly increased the transfer of nitrogen through rivers to estuaries and coastal oceans. In addition, based on our review of available scientific evidence we are confident that human alterations of the nitrogen cycle have: 6) increased the quantity of organic carbon stored within terrestrial ecosystems; 7) accelerated losses of biological diversity, especially losses of plants adapted to efficient use of nitrogen, and losses of the animals and microorganisms that depend on them; and 8) caused changes in the composition and functioning of estuarine and nearshore ecosystems, and contributed to long-term declines in coastal marine fisheries.

5,729 citations


"Global assessment of nitrogen depos..." refers background in this paper

  • ...N deposition effects in mediterranean ecosystems have now been identified, leading to a first estimate of an effect threshold....

    [...]

  • ...…global scale, current N emission scenarios project that most regions will have increased rates of atmospheric N deposition in 2030 (Dentener et al. 2006), which is causing concern about significant impacts on global plant biodiversity (Vitousek et al. 1997, Sala et al. 2000, Phoenix et al. 2006)....

    [...]

Journal ArticleDOI
16 May 2008-Science
TL;DR: Optimizing the need for a key human resource while minimizing its negative consequences requires an integrated interdisciplinary approach and the development of strategies to decrease nitrogen-containing waste.
Abstract: Humans continue to transform the global nitrogen cycle at a record pace, reflecting an increased combustion of fossil fuels, growing demand for nitrogen in agriculture and industry, and pervasive inefficiencies in its use. Much anthropogenic nitrogen is lost to air, water, and land to cause a cascade of environmental and human health problems. Simultaneously, food production in some parts of the world is nitrogen-deficient, highlighting inequities in the distribution of nitrogen-containing fertilizers. Optimizing the need for a key human resource while minimizing its negative consequences requires an integrated interdisciplinary approach and the development of strategies to decrease nitrogen-containing waste.

5,249 citations


"Global assessment of nitrogen depos..." refers background in this paper

  • ...In the current world, atmospheric deposition is not only an important source, but it can also be the dominant source (Galloway et al. 2008)....

    [...]

  • ...By 2005, natural processes had diminished due to land-use change, and anthropogenic processes had increased by over an order of magnitude to ;210 Tg N/yr (Galloway et al. 2008)....

    [...]

  • ...At the global scale, current N emission scenarios project that most regions will have increased rates of atmospheric N deposition in 2030 (Dentener et al. 2006), which is causing concern about significant impacts on global plant biodiversity (Vitousek et al. 1997, Sala et al. 2000, Phoenix et al.…...

    [...]

  • ...By 1860, natural processes still dominated the global input rate (;120 Tg N/yr) because anthropogenic inputs were small (;16 Tg N/yr), almost entirely from cultivation-induced BNF (Galloway et al. 2004)....

    [...]

Journal ArticleDOI
TL;DR: In this paper, the authors compared the natural and anthropogenic controls on the conversion of unreactive N2 to more reactive forms of nitrogen (Nr) and found that human activities increasingly dominate the N budget at the global and at most regional scales, and the terrestrial and open ocean N budgets are essentially dis-connected.
Abstract: This paper contrasts the natural and anthropogenic controls on the conversion of unreactive N2 to more reactive forms of nitrogen (Nr). A variety of data sets are used to construct global N budgets for 1860 and the early 1990s and to make projections for the global N budget in 2050. Regional N budgets for Asia, North America, and other major regions for the early 1990s, as well as the marine N budget, are presented to highlight the dominant fluxes of nitrogen in each region. Important findings are that human activities increasingly dominate the N budget at the global and at most regional scales, the terrestrial and open ocean N budgets are essentially dis- connected, and the fixed forms of N are accumulating in most environmental reservoirs. The largest uncertainties in our understanding of the N budget at most scales are the rates of natural biological nitrogen fixation, the amount of Nr storage in most environmental reservoirs, and the production rates of N2 by denitrification.

4,555 citations


"Global assessment of nitrogen depos..." refers background in this paper

  • ...The N cycling in ecosystems is originally derived from three main sources: biological N fixation (BNF), mineralization, and atmospheric deposition....

    [...]

Book
01 Jan 1999
TL;DR: In this article, a taxonomic index (genera) of alpine plants is presented, with a brief review of water relations and water relations of alpin plants in the alpine life zone.
Abstract: 1 Plant ecology at high elevations.- The concept of limitation.- A regional and historical account.- The challenge of alpine plant research.- 2 The alpine life zone.- Altitudinal boundaries.- Global alpine land area.- Alpine plant diversity.- Origin of alpine floras.- Alpine growth forms.- 3 Alpine climate.- Which alpine climate.- Common features of alpine climates.- Regional features of alpine climates.- 4 The climate plants experience.- Interactions of relief, wind and sun.- How alpine plants influence their climate.- The geographic variation of alpine climate.- 5 Life under snow: protection and limitation.- Temperatures under snow.- Solar radiation under snow.- Gas concentrations under snow.- Plant responses to snowpack.- 6 Alpine soils.- Physics of alpine soil formation.- The organic compound.- The interaction of organic and inorganic compounds.- 7 Alpine treelines.- About trees and lines.- Current altitudinal positions of climatic treelines.- Treeline-climate relationships.- Intrazonal variations and pantropical plateauing of alpine treelines.- Treelines in the past.- Attempts at a functional explanation of treelines.- A hypothesis for treeline formation.- Growth trends near treelines.- Evidence for sink limitation.- 8 Climatic stress.- Survival of low temperature extremes.- Avoidance and tolerance of low temperature extremes.- Heat stress in alpine plants.- Ultraviolet radiation - a stress factor.- 9 Water relations.- Ecosystem water balance.- Soil moisture at high altitudes.- Plant water relations - a brief review of principles.- Water relations of alpine plants.- Desiccation stress.- Water relations of special plant types.- 10 Mineral nutrition.- Soil nutrients.- The nutrient status of alpine plants.- Nutrient cycling and nutrient budgets.- Nitrogen fixation.- Mycorrhiza.- Responses of vegetation to variable nutrient supply.- 11 Uptake and loss of carbon.- Photosynthetic capacity of alpine plants.- Photosynthetic responses to the environment.- Daily carbon gain of leaves.- The seasonal carbon gain of leaves.- C4 and CAM photosynthesis at high altitudes.- Tissue respiration of alpine plants.- Ecosystem carbon balance.- 12 Carbon investments.- Non-structural carbohydrates.- Lipids and energy content.- Carbon costs of leaves and roots.- Whole plant carbon allocation.- 13 Growth dynamics and phenology.- Seasonal growth.- Diurnal leaf extension.- Rates of plant dry matter accumulation.- Functional duration of leaves and roots.- 14 Cell division and tissue formation.- Cell size and plant size.- Mitosis and the cell cycle.- From meristem activity to growth control.- 15 Plant biomass production.- The structure of alpine plant canopies.- Primary productivity of alpine vegetation.- Plant dry matter pools.- Biomass losses through herbivores.- 16 Plant reproduction.- Flowering and pollination.- Seed development and seed size.- Germination.- Alpine seed banks and natural recruitment.- Clonal propagation.- Alpine plant age.- Community processes.- 17 Global change at high elevation.- Alpine land use.- The impact of altered atmospheric chemistry.- Climatic change and alpine ecosystems.- References (with chapter annotation).- Taxonomic index (genera).- Geographical index.- Color plates.- Plant life forms.- The alpine life zone.- Environmental stress.- The human dimension.

2,971 citations

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