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

Ecological Applications, Journal Year: 2010, Volume and Issue: 20(1), P. 30 - 59

Published: Jan. 1, 2010

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

Language: Английский

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Microclimate moderates plant responses to macroclimate warming

Proceedings of the National Academy of Sciences, Journal Year: 2013, Volume and Issue: 110(46), P. 18561 - 18565

Published: Oct. 28, 2013

Significance Around the globe, climate warming is increasing dominance of warm-adapted species—a process described as “thermophilization.” However, thermophilization often lags behind itself, with some recent studies showing no response at all. Using a unique database more than 1,400 resurveyed vegetation plots in forests across Europe and North America, we document significant understory vegetation. to macroclimate was attenuated whose canopies have become denser. This microclimatic effect likely reflects cooler forest-floor temperatures via increased shading during growing season denser forests. Because standing stocks trees many temperate decades, microclimate may commonly buffer plant responses warming.

Language: Английский

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Soil compaction impact and modelling. A review

Agronomy for Sustainable Development, Journal Year: 2012, Volume and Issue: 33(2), P. 291 - 309

Published: Jan. 30, 2012

Compaction of agricultural soils is a concern for many soil scientists and farmers since compaction, due to heavy field traffic, has resulted in yield reduction most agronomic crops throughout the world. Soil compaction physical form degradation that alters structure, limits water air infiltration, reduces root penetration soil. Consequences are still underestimated. A complete understanding processes involved necessary meet future global challenge food security. We review here advances understanding, quantification, prediction effects compaction. found following major points: (1) When exposed vehicular traffic load, contents, texture organic matter three main factors which determine degree compactness (2) direct on properties such as bulk density, strength, porosity; therefore, these parameters can be used quantify compactness. (3) Modified alter elements mobility change nitrogen carbon cycles favour more emissions greenhouse gases under wet conditions. (4) Severe induces deformation, stunted shoot growth, late germination, low germination rate, high mortality rate. (5) decreases biodiversity by decreasing microbial biomass, enzymatic activity, fauna, ground flora. (6) Boussinesq equations finite element method models, predict restricted elastic domain do not consider existence preferential paths stress propagation localization deformation compacted soils. (7) Recent physics granular media mechanics relevant should progress modelling

Language: Английский

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

Ecological Applications, Journal Year: 2011, Volume and Issue: 21(8), P. 3049 - 3082

Published: May 25, 2011

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

Language: Английский

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Direct and indirect effects of alien insect herbivores on ecological processes and interactions in forests of eastern North America

Biological Invasions, Journal Year: 2009, Volume and Issue: 12(2), P. 389 - 405

Published: Nov. 5, 2009

Language: Английский

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Altered dynamics of forest recovery under a changing climate

Global Change Biology, Journal Year: 2013, Volume and Issue: 19(7), P. 2001 - 2021

Published: March 25, 2013

Forest regeneration following disturbance is a key ecological process, influencing forest structure and function, species assemblages, ecosystem-climate interactions. Climate change may alter recovery dynamics or even prevent recovery, triggering feedbacks to the climate system, altering regional biodiversity, affecting ecosystem services provided by forests. Multiple lines of evidence - including global-scale patterns in dynamics; responses experimental manipulation CO2 , temperature, precipitation; that has already occurred; theory; earth system models all indicate are sensitive climate. However, synthetic understanding how atmospheric shape trajectories lacking. Here, we review these separate evidence, which together demonstrate being impacted increasing changing Rates generally increase with water availability. Drought reduces growth live biomass forests ages, having particularly strong effect on seedling recruitment survival. Responses individual trees whole-forest ecosystems manipulations often vary age, implying different ages will respond differently change. Furthermore, within community typically exhibit differential climate, altered can have important consequences for function. Age- species-dependent provide mechanism push some past critical thresholds such they fail recover their previous state disturbance. Altered result positive negative Future research this topic corresponding improvements be future system.

Language: Английский

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Spatial models reveal the microclimatic buffering capacity of old-growth forests

Science Advances, Journal Year: 2016, Volume and Issue: 2(4)

Published: April 1, 2016

Spatial models of under-canopy temperature show that old-growth forests are cooler in spring months than mature forest plantations.

Language: Английский

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Driving factors behind the eutrophication signal in understorey plant communities of deciduous temperate forests

Journal of Ecology, Journal Year: 2011, Volume and Issue: 100(2), P. 352 - 365

Published: Nov. 28, 2011

Summary 1. Atmospheric nitrogen (N) deposition is expected to change forest understorey plant community composition and diversity, but results of experimental addition studies observational are not yet conclusive. A shortcoming studies, which generally based on resurveys or sampling along large gradients, the occurrence temporal spatial confounding factors. 2. We were able assess contribution N versus other ecological drivers communities by combining a approach. Data from 1205 (semi‐)permanent vegetation plots taken 23 rigorously selected resurvey gradient across deciduous temperate in Europe compiled related various local regional driving factors, including rate atmospheric deposition, herbivore densities canopy cover composition. 3. Although no directional species richness occurred, there was considerable floristic turnover shift towards more shade‐tolerant nutrient‐demanding species. However, important explaining observed eutrophication signal. This signal seemed mainly denser changed with higher share easily decomposed litter. 4. Synthesis. Our multi‐site approach clearly demonstrates that one should be cautious when drawing conclusions about impact interpretation shifts single sites regions due other, concurrent, changes. Even though effects chronically increased apparently obscured changes, accumulated might still have significant impact. research needed whether this time bomb will indeed explode canopies open up again.

Language: Английский

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Effects of experimental nitrogen additions on plant diversity in an old‐growth tropical forest

Global Change Biology, Journal Year: 2010, Volume and Issue: 16(10), P. 2688 - 2700

Published: Jan. 13, 2010

Abstract Response of plant biodiversity to increased availability nitrogen (N) has been investigated in temperate and boreal forests, which are typically N‐limited, but little is known tropical forests. We examined the effects artificial N additions on diversity (species richness, density cover) understory layer an saturated old‐growth forest southern China test following hypothesis: decrease forests primarily from N‐mediated changes soil properties. Experimental were administered at levels July 2003 2008: no addition (Control); 50 kg ha −1 yr (Low‐N); 100 (Medium‐N), 150 (High‐N). Results showed that species exhibited positive growth response any level during study period. Although low‐to‐medium (≤100 ) generally did not alter through time, high significantly reduced diversity. This was most closely related declines within tree seedling fern functional groups, as well significant increases acidity Al mobility, decreases Ca fine‐root biomass. mechanism for loss provides sharp contrast competition‐based mechanisms suggested studies communities other Our results suggest high‐N can this may vary with rate addition.

Language: Английский

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The functional role of temperate forest understorey vegetation in a changing world

Global Change Biology, Journal Year: 2019, Volume and Issue: 25(11), P. 3625 - 3641

Published: July 13, 2019

Abstract Temperate forests cover 16% of the global forest area. Within these forests, understorey is an important biodiversity reservoir that can influence ecosystem processes and functions in multiple ways. However, we still lack a thorough understanding relative importance for temperate functioning. As result, understoreys are often ignored during assessments functioning changes thereof under change. We here compiled studies quantify functioning, focussing on litter production, nutrient cycling, evapotranspiration, tree regeneration, pollination pathogen dynamics. describe mechanisms driving develop conceptual framework synthesizing possible effects change drivers understorey‐mediated Our review illustrates understorey's contribution to significant but varies depending function environmental context, more importantly, characteristics overstorey. To predict its change, argue simultaneous investigation both overstorey functional responses will be crucial. shows such very scarce, only available limited set quantification, providing little data forecast

Language: Английский

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