Impacts of nitrogen addition on plant species richness and abundance : A global meta-analysis
Midolo, Gabriele ; Alkemade, Rob ; Schipper, Aafke M. ; Benítez-López, Ana ; Perring, Michael P. ; Vries, Wim de - \ 2019
Global Ecology and Biogeography 28 (2019)3. - ISSN 1466-822X - p. 398 - 413.
anthropogenic impacts - biodiversity - eutrophication - global change - GLOBIO - soil acidification - vegetation
Aim: Experimental nitrogen (N) addition (fertilization) studies are commonly used to quantify the impacts of increased N inputs on plant biodiversity. However, given that plant community responses can vary considerably among individual studies, there is a clear need to synthesize and generalize findings with meta-analytical approaches. Our goal was to quantify changes in species richness and abundance in plant communities in response to N addition across different environmental contexts, while controlling for different experimental designs. Location: Global. Time period: Data range: 1985–2016; Publication years: 1990–2018. Major taxa studied: Plants. Methods: We performed a meta-analysis of 115 experiments reported in 85 studies assessing the effects of N addition on terrestrial natural and semi-natural plant communities. We quantified local-scale changes in plant biodiversity in relationship to N addition using four metrics: species richness (SR), individual species abundance (IA), mean species abundance (MSA) and geometric mean abundance (GMA). Results: For all metrics, greater amounts of annual N addition resulted in larger declines in plant diversity. Additionally, MSA decreased more steeply with N that was applied in reduced (NH4 +) rather than oxidized ((NO− 3)) form. Loss of SR with increasing amounts of N was found to be larger in warmer sites. Furthermore, greater losses of SR were found in sites with longer experimental durations, smaller plot sizes and lower soil cation exchange capacity. Finally, reductions in the abundance of individual species were larger for N-sensitive plant life-form types (legumes and non-vascular plants). Main conclusions: N enrichment decreases both SR and abundance of plants in N-addition experiments, but the magnitude of the response differs among biodiversity metrics and with the environmental and experimental context. This underlines the importance of integrating multiple dimensions of biodiversity and relevant modifying factors into assessments of biodiversity responses to global environmental change.
Impacts of European livestock production : Nitrogen, sulphur, phosphorus and greenhouse gas emissions, land-use, water eutrophication and biodiversity
Leip, Adrian ; Billen, Gilles ; Garnier, Josette ; Grizzetti, Bruna ; Lassaletta, Luis ; Reis, Stefan ; Simpson, David ; Sutton, M.A. ; Vries, Wim De; Weiss, Franz ; Westhoek, Henk - \ 2015
Environmental Research Letters 10 (2015)11. - ISSN 1748-9326
air quality - biodiversity loss - climate change - coastal eutrophication - European Union - livestock production - soil acidification
Livestock production systems currently occupy around 28% of the land surface of the European Union (equivalent to 65% of the agricultural land). In conjunction with other human activities, livestock production systems affect water, air and soil quality, global climate and biodiversity, altering the biogeochemical cycles of nitrogen, phosphorus and carbon. Here, we quantify the contribution of European livestock production to these major impacts. For each environmental effect, the contribution of livestock is expressed as shares of the emitted compounds and land used, as compared to the whole agricultural sector. The results show that the livestock sector contributes significantly to agricultural environmental impacts. This contribution is 78% for terrestrial biodiversity loss, 80% for soil acidification and air pollution (ammonia and nitrogen oxides emissions), 81% for global warming, and 73% for water pollution (both N and P). The agriculture sector itself is one of the major contributors to these environmental impacts, ranging between 12% for global warming and 59% for N water quality impact. Significant progress in mitigating these environmental impacts in Europe will only be possible through a combination of technological measures reducing livestock emissions, improved food choices and reduced food waste of European citizens.
Spatial boundary of urban ‘acid islands’ in China
Du, E. ; Vries, W. de; Liu, X. ; Fang, J. ; Galloway, J.N. ; Jiang, Y. - \ 2015
Scientific Reports 5 (2015). - ISSN 2045-2322 - 9 p.
atmospheric deposition - nitrogen deposition - air-pollution - soil acidification - emissions - canopy - forest - rain - ecosystems - cities
Elevated emissions of sulfur dioxide, nitrogen oxides and ammonia in China have resulted in high levels of sulfur and nitrogen deposition, being contributors to soil acidification, especially in and near large cities. However, knowledge gaps still exist in the way that large cities shape spatial patterns of acid deposition. Here, we assessed the patterns of pH, sulfate, nitrate and ammonium in bulk precipitation and throughfall in southern China’s forests by synthesizing data from published literature. Concentrations and fluxes of sulfate, nitrate and ammonium in bulk precipitation and throughfall exhibited a power-law increase with a closer distance to the nearest large cities, and accordingly pH showed a logarithmic decline. Our findings indicate the occurrence of urban ‘acid islands’ with a critical radius of approximately 70¿km in southern China, receiving potential acid loads of more than 2 keq ha-1 yr-1. These urban acid islands covered an area of 0.70¿million km2, accounting for nearly 30% of the land area in southern China. Despite a significant capacity to neutralize acids in precipitation, our analysis highlights a substantial contribution of ammonium to potential acid load. Our results suggest a joint control on emissions of multiple acid precursors from urban areas in southern China
Driving factors behind the eutrophication signal in understorey plant communities of deciduous temperate forests
Verheyen, K. ; Baeten, L. ; Frenne, P. De; Bernhardt-Römermann, M. ; Brunet, J. ; Cornelis, J. ; Decocq, G. ; Eriksson, O. ; Dierschke, H. ; Hommel, P.W.F.M. - \ 2012
Journal of Ecology 100 (2012)2. - ISSN 0022-0477 - p. 352 - 365.
coppice-with-standards - ellenberg indicator values - ground-layer vegetation - white-tailed deer - nitrogen deposition - leaf-litter - species richness - atmospheric deposition - soil acidification - field-measurements
1. Atmospheric nitrogen (N) deposition is expected to change forest understorey plant community composition and diversity, but results of experimental addition studies and observational studies are not yet conclusive. A shortcoming of observational studies, which are generally based on resurveys or sampling along large deposition gradients, is the occurrence of temporal or spatial confounding factors. 2. We were able to assess the contribution of N deposition versus other ecological drivers on forest understorey plant communities by combining a temporal and spatial approach. Data from 1205 (semi-)permanent vegetation plots taken from 23 rigorously selected understorey resurvey studies along a large deposition gradient across deciduous temperate forest in Europe were compiled and related to various local and regional driving factors, including the rate of atmospheric N deposition, the change in large herbivore densities and the change in canopy cover and composition. 3. Although no directional change in species richness occurred, there was considerable floristic turnover in the understorey plant community and a shift in species composition towards more shade-tolerant and nutrient-demanding species. However, atmospheric N deposition was not important in explaining the observed eutrophication signal. This signal seemed mainly related to a shift towards a denser canopy cover and a changed canopy species composition with a higher share of species with more easily decomposed litter. 4. Synthesis. Our multi-site approach clearly demonstrates that one should be cautious when drawing conclusions about the impact of atmospheric N deposition based on the interpretation of plant community shifts in single sites or regions due to other, concurrent, ecological changes. Even though the effects of chronically increased N deposition on the forest plant communities are apparently obscured by the effects of canopy changes, the accumulated N might still have a significant impact. However, more research is needed to assess whether this N time bomb will indeed explode when canopies will open up again.
Uncertainty propagation analysis of an N2O emission model at the plot and landscape scale
Nol, L. ; Heuvelink, G.B.M. ; Veldkamp, A. ; Vries, W. de; Kros, J. - \ 2010
Geoderma 159 (2010)1-2. - ISSN 0016-7061 - p. 9 - 23.
nitrous-oxide emissions - sensitivity analysis - soil acidification - netherlands - inventory - denitrification - grassland - europe - agriculture - ecosystems
Nitrous oxide (N2O) emission from agricultural land is an important component of the total annual greenhouse gas (GHG) budget. In addition, uncertainties associated with agricultural N2O emissions are large. The goals of this work were (i) to quantify the uncertainties of modelled N2O emissions caused by model input uncertainty at point and landscape scale (i.e. resolution), and (ii) to identify the main sources of input uncertainty at both scales. For the Dutch western fen meadow landscape, we performed a Monte Carlo uncertainty propagation analysis using the INITIATOR model. The Monte Carlo analysis used novel and state-of-the-art methods for estimating and simulating continuous-numerical and categorical input variables, handling spatial and cross-correlations and analyzing spatial aggregation effects. Spatial auto- and cross-correlation of uncertain numerical inputs that are spatially variable were represented by the linear model of coregionalization. Bayesian Maximum Entropy was used to quantify the uncertainty of spatially variable categorical model inputs. Stochastic sensitivity analysis was used to analyze the contribution of groups of uncertain inputs to the uncertainty of the N2O emission at point and landscape scale. The average N2O emission at landscape scale had a mean of 20.5 kg N2O-N ha(-1) yr(-1) and a standard deviation of 10.7 kg N2O-N ha(-1) yr(-1), producing a relative uncertainty of 52%. At point scale, the relative error was on average 78%, indicating that upscaling decreases uncertainty. Soil inputs and denitrification and nitrification inputs were the main sources of uncertainty in N2O emission at point scale. At landscape scale, uncertainty in soil inputs averaged out and uncertainty in denitrification and nitrification inputs was the dominant source of uncertainty. This was partly because these inputs were assumed constant across areas with the same soil type and land use, which is probably not very realistic. Experiments at landscape scale are needed to assess the spatial variability of these fractions and analyze how a more realistic representation influences the uncertainty budget at landscape scale. This research confirms that results from uncertainty analyses are often scale dependent and that results for one scale cannot directly be extrapolated to other scales. (C) 2010 Elsevier B.V. All rights reserved.
Relation between forest vegetation, atmospheric deposition and site conditions at regional and European scales
Dobben, H.F. van; Vries, W. de - \ 2010
Environmental Pollution 158 (2010)3. - ISSN 0269-7491 - p. 921 - 933.
ellenberg indicator values - ca-al ratio - deciduous forest - nitrogen deposition - aluminum toxicity - critical loads - soil acidification - base cation - heathland - ecosystems
Several monitoring programs have been set up to assess effects of atmospheric deposition on forest ecosystems. The aim of the present study was to evaluate effects on the understorey vegetation, based on the first round of a regional (the Netherlands) and a European forest monitoring program. A multivariate statistical analysis showed surprisingly similar results for both data sets; the vegetation appeared to be largely determined by the ‘traditional’ factors soil, climate, and tree species, but there was a small but statistically significant effect of atmospheric deposition. The effects of deposition include a slight shift towards nitrophytic species at high N deposition in the European network, and towards acidophytic species at high S-deposition in the Dutch network. The relatively small effect of atmospheric deposition is understandable in view of the very large natural variation in environmental conditions. Time series of both vegetation and environment are needed to assess deposition effects in detail. There is a small but noticeable effect of anthropogenic atmospheric deposition on forest vegetation in Europe.
Analyses of the impact of changes in atmospheric deposition and climate on forest growth in European monitoring plots: A stand growth approach
Solberg, S. ; Dobbertin, M. ; Reinds, G.J. ; Andreassen, K. ; Lange, H. ; Garcia Fernandez, P. ; Hildingsson, A. ; Vries, W. de - \ 2009
Forest Ecology and Management 258 (2009)8. - ISSN 0378-1127 - p. 1735 - 1750.
nitrogen deposition - acid deposition - picea-abies - tree growth - carbon sequestration - soil acidification - density index - norway - spruce - responses
During the last 15 years a number of studies have shown increasing forest growth in central Europe, rather than a decline as was expected due to negative effects of air pollution. We have here used data from intensive monitoring plots spread over Europe for a five year period in order to examine the influence of environmental factors on forest growth. Evaluations focussed on the influence of nitrogen, sulphur and acid deposition, temperatures, precipitation and on a drought index calculated as deviation from the long-term mean. The study included the main tree species Norway spruce, Scots pine, common beech as well as European and sessile oak and was based on data from 363 plots. As many other factors besides nitrogen and temperature influence tree growth, expected stem volume increments were modelled using site productivity, stand age and a stand density index. Relative volume increment was then calculated as actual increment in % of expected increment. The site productivity, assumed to be given by site conditions and past environmental conditions, was either taken from expert estimates or computed from site index curves from northern, central and southern Europe. The model explained between 18% and 39% of the variance with site productivity being positively related and age negatively related to actual increment. The various models and statistical approaches were fairly consistent, and indicated a fertilizing effect of nitrogen deposition, with slightly above one percent increase in volume increment per kg of nitrogen deposition per ha and year. This was most clear for spruce and pine, and most pronounced for plots having soil C/N ratios above 25. Also, we found a positive relationship between relative increment and summer temperature, i.e. May–August mean temperature deviation from the 1961–1990 means. The cause–effect relationship here is, however, less certain. Other influences were uncertain. Possibly, sulphur and acid deposition have effects on growth, but these effects are obscured by, and outweighed by the positive effect of nitrogen deposition, because of collinearity between these variables. Drought effects were uncertain also, and one reason for this might be large uncertainties in the precipitation data: precipitation measured on some 50% of the plots correlated poorly with the precipitation data obtained from Europe-wide databases. The major finding of this study was a positive relationship between higher than normal volume increment on one hand and nitrogen deposition on the other hand.
Stochastic simulation of large grids using free and public domain software
Bruin, S. de; Wit, A.J.W. de - \ 2005
Computers and Geosciences 31 (2005)7. - ISSN 0098-3004 - p. 828 - 836.
soil acidification - uncertainty - program - reservoir - entropy
This paper proposes a tiled map procedure enabling sequential indicator simulation on grids consisting of several tens of millions of cells, without putting excessive memory requirements. Spatial continuity across map tiles is handled by conditioning adjacent tiles on their shared boundaries. Tiles across the area can be characterized by dissimilar models of spatial continuity (semi-variograms) thus relieving the requirement of a global stationarity decision. Additionally, the approach provides a simple mechanism for reseeding the pseudo random number generator. Implementation of the algorithm involved small modifications to a GSLIB program and Bash and awk scripting. The software was stable on several platforms, including 32-bit systems with a 4 Gb memory addressing limit. In an experiment we simulated 25 realizations of a 11,274×13,000 grid representing local uncertainty in the Dutch land cover at 25 m resolution. With the objective of mimicking the typical absence of well-distributed hard reference data, the simulations were only conditioned on local prior class probabilities and semi-variograms. Output was evaluated on the basis of reproduction of target levels of (1) cover type proportions, (2) overall class label accuracy and (3) spatially averaged local Shannon entropy. As expected, the realized statistics differed significantly from the target levels. However, the differences were consistent over the borders and the insides of map tiles. Thus, they did not result from the tiled map procedure but rather should be attributed to the used semi-conditional sequential indicator simulator. The current implementation can easily be adapted to accept other simulation algorithms