Impacts of nitrogen deposition on terrestrial plant diversity: a meta-analysis in China

2019 ◽  
Vol 12 (6) ◽  
pp. 1025-1033 ◽  
Author(s):  
Wen-Juan Han ◽  
Jia-Yu Cao ◽  
Jin-Liang Liu ◽  
Jia Jiang ◽  
Jian Ni

AbstractAimsWith the global atmospheric nitrogen (N) deposition increasing, the effect of N deposition on terrestrial plant diversity has been widely studied. Some studies have reviewed the effects of N deposition on plant species diversity; however, all studies addressed the effects of N deposition on plant community focused on species richness in specific ecosystem. There is a need for a systematic meta-analysis covering multiple dimensions of plant diversity in multiple climate zones and ecosystems types. Our goal was to quantify changes in species richness, evenness and uncertainty in plant communities in response to N addition across different environmental and experimental contexts.MethodsWe performed a meta-analysis of 623 experimental records published in English and Chinese journals to evaluate the response of terrestrial plant diversity to the experimental N addition in China. Three metrics were used to quantify the change in plant diversity: species richness (SR), evenness (Pielou index) uncertainty (Shannon index).Important FindingsResults showed that (i) N addition negatively affected SR in temperate, Plateau zones and subtropical zone, but had no significant effect on Shannon index in subtropical zones; (ii) N addition decreased SR, Shannon index and Pielou index in grassland, and the negative effect of N addition on SR was stronger in forest than in grassland; (iii) N addition negatively affected plant diversity (SR, Shannon index and Pielou index) in the long term, whereas it did not affect plant diversity in the short term. Furthermore, the increase in N addition levels strengthened the negative effect of N deposition on plant diversity with long experiment duration; and (iv) the negative effect of ammonium nitrate (NH4NO3) addition on SR was stronger than that of urea (CO(NH2)2) addition, but the negative effect of NH4NO3 addition on Pielou index was weaker than that of CO(NH2)2 addition. Our results indicated that the effects of N addition on plant diversity varied depending on climate zones, ecosystem types, N addition levels, N type and experiment duration. This underlines the importance of integrating multiple dimensions of plant diversity and multiple factors into assessments of plant diversity to global environmental change.

2018 ◽  
Author(s):  
Liming Yan ◽  
Xiaoni Xu ◽  
Jianyang Xia

Abstract. Terrestrial plant growth and ecosystem productivity are strongly limited by availability of nitrogen (N). Atmospheric deposition of wet N as nitrate and ammonium has been rapidly increased since the industrial revolution, associated with a high spatial variation of changes in the ammonium- to nitrate-N ratio (i.e., NH4+-N / NO3−-N). However, whether and how terrestrial plants respond differently to NH4+-N and NO3−-N addition have never been quantitatively synthesized. Here, we first did a literature survey and analysis on the model projections of future changes in NH4+-N / NO3−-N in atmospheric N deposition. Most models predicted an increase in the global average of NH4+-N / NO3−-N ratio, but decreasing trends in western Europe and eastern China. Then, a meta-analysis was applied to compare the different growth responses of 402 plant species to NH4+-N and NO3−-N addition from 217 N fertilization studies. In general, a greater response of plant growth to NH4+-N (+6.3 % g−1 N) than NO3−-N (+1.0 % g−1 N) addition was detected across all species. The larger sensitivity of plant growth to NH4+- than NO3−-N was found in all plant functional types except for grasses. In addition, the NO3−-N addition promoted terrestrial plants to allocate more biomass to above-ground, whereas NH4+-N addition significantly enhanced below- but not above-ground growth. These results imply that the global accelerating N deposition could stimulate plant growth more in regions with increasing (e.g., North America) than decreasing (e.g., eastern China) NH4+-N / NO3−-N ratio. The findings suggest future assessments and predictions on the vegetation response to atmospheric N enrichment could benefit from a better understanding of plant strategies for acquiring different forms of N.


2009 ◽  
Vol 57 (2) ◽  
pp. 197-203 ◽  
Author(s):  
T. Sinkovč

The botanical composition of grasslands determines the agronomic and natural values of swards. Good grassland management usually improves herbage value, but on the other hand it frequently decreases the plant diversity and species richness in the swards. In 1999 a field trial in a split-plot design with four replicates was therefore established on the Arrhenatherion type of vegetation in Ljubljana marsh meadows in order to investigate this relationship. Cutting regimes (2 cuts — with normal and delayed first cut, 3 cuts and 4 cuts per year) were allocated to the main plots and fertiliser treatments (zero fertiliser — control, PK and NPK with 2 or 3 N rates) were allocated to the sub-plots. The results at the 1 st cutting in the 5 th trial year were as follows: Fertilising either with PK or NPK had no significant negative effect on plant diversity in any of the cutting regimes. In most treatments the plant number even increased slightly compared to the control. On average, 20 species were listed on both unfertilised and fertilised swards. At this low to moderate level of exploitation intensity, the increased number of cuts had no significant negative effect on plant diversity either (19 species at 2 cuts vs. 20 species at 3 or 4 cuts). PK fertilisation increased the proportion of legumes in the herbage in the case of 2 or 3 cuts. The proportion of grasses in the herbage increased in all the fertilisation treatments with an increased numbers of cuts. Fertiliser treatment considerably reduced the proportion of marsh horsetail ( Equisetum palustre ) in the herbage of the meadows. This effect was even more pronounced at higher cut numbers. The proportion of Equisetum palustre in the herbage was the highest in the unfertilised sward with 2 cuts (26.4 %) and the lowest in the NPK-fertilised sward with 4 cuts (1.4%).


2020 ◽  
Vol 100 (1) ◽  
pp. 11-25 ◽  
Author(s):  
Guoyong Yan ◽  
Xiongde Dong ◽  
Binbin Huang ◽  
Honglin Wang ◽  
Ziming Hong ◽  
...  

We conducted a field experiment with four levels of simulated nitrogen (N) deposition (0, 2.5, 5, and 7.5 g N m−2 yr−1, respectively) to investigate the response of litter decomposition of Pinus koraiensis (PK), Tilia amurensis (TA), and their mixture to N deposition during winter and growing seasons. Results showed that N addition significantly increased the mass loss of PK litter and significantly decreased the mass loss of TA litter throughout the 2 yr decomposition processes, which indicated that the different responses in the decomposition of different litters to N addition can be species specific, potentially attributed to different litter chemistry. The faster decomposition of PK litter with N addition occurred mainly in the winter, whereas the slower decomposition of TA litter with N addition occurred during the growing season. Moreover, N addition had a positive effect on the release of phosphorus, magnesium, and manganese for PK litter and had a negative effect on the release of carbon, iron, and lignin for TA litter. Decomposition and nutrient release from mixed litter with N addition showed a non-additive effect. The mass loss from litter in the first winter and over the entire study correlated positively with the initial concentration of cellulose, lignin, and certain nutrients in the litter, demonstrating the potential influence of different tissue chemistries.


2011 ◽  
Vol 8 (8) ◽  
pp. 2341-2350 ◽  
Author(s):  
L. Song ◽  
X. Bao ◽  
X. Liu ◽  
Y. Zhang ◽  
P. Christie ◽  
...  

Abstract. Chinese grasslands are extensive natural ecosystems that comprise 40 % of the total land area of the country and are sensitive to N deposition. A field experiment with six N rates (0, 30, 60, 120, 240, and 480 kg N ha−1 yr−1) was conducted at Duolun, Inner Mongolia, during 2005 and 2010 to identify some effects of N addition on a temperate steppe ecosystem. The dominant plant species in the plots were divided into two categories, grasses and forbs, on the basis of species life forms. Enhanced N deposition, even as little as 30 kg N ha−1 yr−1 above ambient N deposition (16 kg N ha−1 yr−1), led to a decline in species richness. The cover of grasses increased with N addition rate but their species richness showed a weak change across N treatments. Both species richness and cover of forbs declined strongly with increasing N deposition as shown by linear regression analysis (p < 0.05). Increasing N deposition elevated aboveground production of grasses but lowered aboveground biomass of forbs. Plant N concentration, plant δ15N and soil mineral N increased with N addition, showing positive relationships between plant δ15N and N concentration, soil mineral N and/or applied N rate. The cessation of N application in the 480 kg N ha−1 yr−1 treatment in 2009 and 2010 led to a slight recovery of the forb species richness relative to total cover and aboveground biomass, coinciding with reduced plant N concentration and soil mineral N. The results show N deposition-induced changes in soil N transformations and plant N assimilation that are closely related to changes in species composition and biomass accumulation in this temperate steppe ecosystem.


2014 ◽  
Author(s):  
Lars Gamfeldt ◽  
Jonathan S Lefcheck ◽  
Jarrett E K Byrnes ◽  
Bradley J Cardinale ◽  
J. Emmett Duffy ◽  
...  

Marine ecosystems are experiencing rapid and pervasive loss of species. Understanding the consequences of species loss is critical to effectively managing these systems. Over the last several years, numerous experimental manipulations of species richness have been performed, yet existing quantitative syntheses have focused on a just a subset of processes measured in experiments and, as such, have not summarized the full data available from marine systems. Here, we present the results of a meta-analysis of 174 marine experiments from 42 studies that have manipulated the species richness of organisms across a range of taxa and trophic levels and analysed the consequences for various ecosystem processes (categorised as production, consumption or biogeochemical fluxes). Our results show that, generally, mixtures of species tend to enhance levels of ecosystem function relative to the average component species in monoculture, but have no or negative effect on functioning relative to the ‘highest-performing' species. These results are largely consistent with those from other syntheses, and extend conclusions to ecological functions that are most commonly measured in the marine realm (e.g. nutrient release from sediment bioturbation). For experiments that manipulated three or more levels of richness, we attempted to discern the functional form of the BEF relationship. We found that, for response variables categorised as consumption, a power-function best described the relationship, which is also consistent with previous findings. However, we identified a linear relationship between richness and production. Combined, our results suggest that losses of species will, on average, tend to alter the functioning of marine ecosystems. We outline several research frontiers that will allow us to more fully understand how, why, and when diversity may drive the functioning of marine ecosystems.


2014 ◽  
Author(s):  
Lars Gamfeldt ◽  
Jonathan S Lefcheck ◽  
Jarrett E K Byrnes ◽  
Bradley J Cardinale ◽  
J. Emmett Duffy ◽  
...  

Marine ecosystems are experiencing rapid and pervasive loss of species. Understanding the consequences of species loss is critical to effectively managing these systems. Over the last several years, numerous experimental manipulations of species richness have been performed, yet existing quantitative syntheses have focused on a just a subset of processes measured in experiments and, as such, have not summarized the full data available from marine systems. Here, we present the results of a meta-analysis of 174 marine experiments from 42 studies that have manipulated the species richness of organisms across a range of taxa and trophic levels and analysed the consequences for various ecosystem processes (categorised as production, consumption or biogeochemical fluxes). Our results show that, generally, mixtures of species tend to enhance levels of ecosystem function relative to the average component species in monoculture, but have no or negative effect on functioning relative to the ‘highest-performing' species. These results are largely consistent with those from other syntheses, and extend conclusions to ecological functions that are most commonly measured in the marine realm (e.g. nutrient release from sediment bioturbation). For experiments that manipulated three or more levels of richness, we attempted to discern the functional form of the BEF relationship. We found that, for response variables categorised as consumption, a power-function best described the relationship, which is also consistent with previous findings. However, we identified a linear relationship between richness and production. Combined, our results suggest that losses of species will, on average, tend to alter the functioning of marine ecosystems. We outline several research frontiers that will allow us to more fully understand how, why, and when diversity may drive the functioning of marine ecosystems.


2015 ◽  
Vol 12 (11) ◽  
pp. 3499-3512 ◽  
Author(s):  
Q.-Y. Tian ◽  
N.-N. Liu ◽  
W.-M. Bai ◽  
L.-H. Li ◽  
W.-H. Zhang

Abstract. Enhanced deposition of atmospheric nitrogen (N) resulting from anthropogenic activities has negative impacts on plant diversity in ecosystems. Several mechanisms have been proposed to explain the species loss. Ion toxicity due to N deposition-induced soil acidification has been suggested to be responsible for species loss in acidic grasslands, while few studies have evaluated the role of soil-mediated homeostasis of ions in species loss under elevated N deposition in grasslands with neutral or alkaline soils. To determine whether soil-mediated processes are involved in changes in biodiversity induced by N deposition, the effects of 9-year N addition on soil properties, aboveground biomass (AGB) and species richness were investigated in an Inner Mongolia steppe. Low to moderate N addition rate (2, 4, 8 g N m−2 yr−1) significantly enhanced AGB of graminoids, while high N addition rate (≥ 16 g N m−2 yr−1) reduced AGB of forbs, leading to an overall increase in AGB of the community under low to moderate N addition rates. Forb richness was significantly reduced by N addition at rates greater than 8 g N m−2 yr−1, while no effect of N addition on graminoid richness was observed, resulting in decline in total species richness. N addition reduced soil pH, depleted base cations (Ca2+, Mg2+ and K+) and mobilized Mn2+, Fe3+, Cu2+ and Al3+ ions in soils. Soil inorganic-N concentration was negatively correlated with forb richness and biomass, explaining 23.59% variation of forb biomass. The concentrations of base cations (Ca2+ and Mg2+) and metal ions (Mn2+, Cu2+ and, Fe3+) showed positively and negatively linear correlation with forb richness, respectively. Changes in the metal ion concentrations accounted for 42.77% variation of forb richness, while reduction of base cations was not associated with the reduction in forb richness. These results reveal that patterns of plant biodiversity in the temperate steppe of Inner Mongolia are primarily driven by increases in metal ion availability, particularly enhanced release of soil Mn2+.


1999 ◽  
Vol 29 (7) ◽  
pp. 1065-1072 ◽  
Author(s):  
Lisa E Schabenberger ◽  
Shepard M Zedaker

This study was established to determine the effects of competition control on loblolly pine (Pinus taeda L.) yield and woody plant diversity in Virginia Piedmont plantations 12-14 years of age. In a factorial experiment, loblolly pine and competing woody vegetation were analyzed at eight levels of competition control: total, two-thirds, one-third, or no woody stem control in combination with either total or no herbaceous vegetation control. Pine yield increased linearly with increasing levels of woody control intensity. As woody control increased, noncrop woody plant basal area and woody plant diversity (Shannon index (H')) in the canopy decreased. Woody plant species richness in the canopy was reduced by herbaceous control and by total woody control. Percent woody cover, H', and species richness in the understory were not affected at any level of competition control. Regression analysis was used to examine relationships between loblolly pine yield, noncrop woody dominance and canopy plant diversity (H'). Pine yield was negatively correlated (R2 = 0.74) with the percentage of noncrop woody basal area (PNCW BA) in the canopy, while canopy diversity was proportional to PNCW BA (R2 = 0.97). Canopy diversity was inversely related to pine yield (R2 = 0.77), with a high trade-off in diversity at low yield levels, but with decreasing sensitivity as pine yield increased.


2018 ◽  
Vol 38 (9) ◽  
Author(s):  
毛晋花 MAO Jinhua ◽  
邢亚娟 XING Yajuan ◽  
闫国永 YAN Guoyong ◽  
王庆贵 WANG Qinggui

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Shu Liao ◽  
Siyi Tan ◽  
Yan Peng ◽  
Dingyi Wang ◽  
Xiangyin Ni ◽  
...  

Abstract Background China’s terrestrial ecosystems have been receiving increasing amounts of reactive nitrogen (N) over recent decades. External N inputs profoundly change microbially mediated soil carbon (C) dynamics, but how elevated N affects the soil organic C that is derived from microbial residues is not fully understood. Here, we evaluated the changes in soil microbial necromass C under N addition at 11 forest, grassland, and cropland sites over China’s terrestrial ecosystems through a meta-analysis based on available data from published articles. Results Microbial necromass C accounted for an average of 49.5% of the total soil organic C across the studied sites, with higher values observed in croplands (53.0%) and lower values in forests (38.6%). Microbial necromass C was significantly increased by 9.5% after N addition, regardless of N forms, with greater stimulation observed for fungal (+ 11.2%) than bacterial (+ 4.5%) necromass C. This increase in microbial necromass C under elevated N was greater under longer experimental periods but showed little variation among different N application rates. The stimulation of soil microbial necromass C under elevated N was proportional to the change in soil organic C. Conclusions The stimulation of microbial residues after biomass turnover is an important pathway for the observed increase in soil organic C under N deposition across China’s terrestrial ecosystems.


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