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Nitrogen (N) deposition and precipitation changes can strongly influence soil microbial properties in arid and semiarid regions. Here, we examined these effects on soil samples from the Inner Mongolia desert steppe of northern China after 7 yr of consecutive simulated N deposition by adding NH4NO3 and manipulation of precipitation, using a dilution...
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Context 1
... strains ZJ4, ZJ11, ZJ18, and ZJ21 belonged to the genus Fusarium, whereas strains ZJ7, ZJ16, ZJ20, and ZJ41 belonged to Aspergillus. One fungal isolate, namely ZJ44, remained unidentified because of a sequencing failure (Table 2). The similarities of all isolated strains with the most similar strain in GenBank were more than 97% (Table 2); hence, no new fungal species were found. ...Context 2
... fungal isolate, namely ZJ44, remained unidentified because of a sequencing failure (Table 2). The similarities of all isolated strains with the most similar strain in GenBank were more than 97% (Table 2); hence, no new fungal species were found. At a depth of 0-2 cm, +N and +N+W treatments decreased species richness (S) and the Shannon-Weiner index (H′); in contrast, +N−W treatment increased S and H′. ...Context 3
... strains ZJ4, ZJ11, ZJ18, and ZJ21 belonged to the genus Fusarium, whereas strains ZJ7, ZJ16, ZJ20, and ZJ41 belonged to Aspergillus. One fungal isolate, namely ZJ44, remained unidentified because of a sequencing failure (Table 2). The similarities of all isolated strains with the most similar strain in GenBank were more than 97% (Table 2); hence, no new fungal species were found. ...Context 4
... fungal isolate, namely ZJ44, remained unidentified because of a sequencing failure (Table 2). The similarities of all isolated strains with the most similar strain in GenBank were more than 97% (Table 2); hence, no new fungal species were found. At a depth of 0-2 cm, +N and +N+W treatments decreased species richness (S) and the Shannon-Weiner index (H′); in contrast, +N−W treatment increased S and H′. ...Citations
... Desert steppe (i.e., highly arid grassland) is one of Inner Mongolia's grassland ecosystems, accounting for 10.7% of its entire grasslands' coverage (Jia et al., 2017) and forming the key transition area between grassland and desert . Plants of desert steppe might be more vulnerable and responsive to climate change than are species in other grassland types (Vale and Brito, 2015). ...
Nitrogen (N) deposition rates are increasing in the temperate steppe due to human activities. Understanding the plastic responses of plant dominant species to increased N deposition through the lens of multiple traits is crucial for species selection in the process of vegetation restoration. Here, we measured leaf morphological, physiological, and anatomical traits of two dominant species (Stipa glareosa and Peganum harmala) after 3-year N addition (0, 1, 3, and 6 g N m⁻² year⁻¹, designated N0, N1, N3, and N6, respectively) in desert steppe of Inner Mongolia. We separately calculated the phenotypic plasticity index (PI) of each trait under different N treatments and the mean phenotypic plasticity index (MPI) of per species. The results showed that N addition increased the leaf N content (LNC) in both species. N6 increased the contents of soluble protein and proline, and decreased the superoxide dismutase (SOD) and the peroxidase (POD) activities of S. glareosa, while increased POD and catalase (CAT) activities of P. harmala. N6 increased the palisade tissue thickness (PT), leaf thickness (LT), and palisade-spongy tissue ratio (PT/ST) and decreased the spongy tissue–leaf thickness ratio (ST/LT) of S. glareosa. Furthermore, we found higher physiological plasticity but lower morphological and anatomical plasticity in both species, with greater anatomical plasticity and MPI in S. glareosa than P. harmala. Overall, multi-traits comparison reveals that two dominant desert-steppe species differ in their plastic responses to N addition. The higher plasticity of S. glareosa provides some insight into why S. glareosa has a broad distribution in a desert steppe.
... In this site, N additions had reduced soil pH from 5.1 to 4.9, which may have contributed to fungal stress (Corre et al., 2010). Nitrogen enrichment shifts fungal community composition (Johnson, 1993;Egerton-Warburton and Allen, 2000;Allison et al., 2008;Allison et al., 2010a;Entwistle et al., 2013;Amend et al., 2016;Morrison et al., 2016;Jia et al., 2017;Chen et al., 2018) more often than not (Porras-Alfaro et al., 2011;Cassman et al., 2016;McHugh et al., 2017). In a temperate forest in the northeastern United States, N fertilization favors stress-tolerant fungi and those with higher gene frequencies of ammonium transporters and amino acid permeases (Morrison et al., 2018;Romero-Olivares et al., 2021). ...
In this case study analysis, we identified fungal traits that were associated with the responses of taxa to 4 global change factors: elevated CO2, warming and drying, increased precipitation, and nitrogen (N) enrichment. We developed a trait-based framework predicting that as global change increases limitation of a given nutrient, fungal taxa with traits that target that nutrient will represent a larger proportion of the community (and vice versa). In addition, we expected that warming and drying and N enrichment would generate environmental stress for fungi and may select for stress tolerance traits. We tested the framework by analyzing fungal community data from previously published field manipulations and linking taxa to functional gene traits from the MycoCosm Fungal Portal. Altogether, fungal genera tended to respond similarly to 3 elements of global change: increased precipitation, N enrichment, and warming and drying. The genera that proliferated under these changes also tended to possess functional genes for stress tolerance, which suggests that these global changes—even increases in precipitation—could have caused environmental stress that selected for certain taxa. In addition, these genera did not exhibit a strong capacity for C breakdown or P acquisition, so soil C turnover may slow down or remain unchanged following shifts in fungal community composition under global change. Since we did not find strong evidence that changes in nutrient limitation select for taxa with traits that target the more limiting nutrient, we revised our trait-based framework. The new framework sorts fungal taxa into Stress Tolerating versus C and P Targeting groups, with the global change elements of increased precipitation, warming and drying, and N enrichment selecting for the stress tolerators.
... Few studies were conducted in the desert steppe of Inner Mongolia but most have been conducted in Polar regions (Simmons et al. 2009), farmland (Dong et al. 2013;Song et al. 2014;Schorpp and Schrader 2017), and forest (Sun et al. 2013). Desert steppes are important parts of Inner Mongolian grasslands, accounting for 10.7% of the whole grassland area in the region (Jia et al. 2017). They are highly arid grasslands, located in the transition area between grassland and desert. ...
Purpose
Global warming and drying are important environmental issues. Our study aimed to investigate how warming and precipitation changes affect soil nematode communities in an Inner Mongolian desert steppe for 10 years.
Materials and methods
Soil nematodes were extracted by the Baermann funnel method. Changes in the nematode communities under artificial warming and precipitation conditions were assayed by analyzing their abundance and ecological indices.
Results and discussion
Soil nematode abundance decreased significantly by 37.47% under artificial warming; however, there was no significant effect of warming on the nematode community diversity. As for precipitation experiment, the decreased precipitation eliminated some of non-dominant nematode genera, such as Pratylenchus, Helicotylenchus, and Aphelenchus. It caused not only a significant decrease (37.65%) in soil nematode abundance but also a more structured food web and shorter food chain. However, nematode faunal analysis indicated that the soil nematode community was more resistant to drought. Both soil nematode abundance and community diversity increased significantly as increase of precipitation. In particular, the abundance of plant parasitic nematodes increased by 46.69%, which may due to the increase in total nitrogen content in soil. Nematode faunal analysis showed that increased precipitation improved soil environment for the nematodes, and increased food web connectivity and food chain length. However, bacterivorous nematode abundance decreased by 74.39%, and the decomposition pathway of the nematode community had switched from the bacterial channel to the fungal channel.
Conclusions
In the Inner Mongolian steppe, both climate drying and warming had negative impacts on soil nematode abundance; however, only drying affected nematode community diversity and food web structure and slowly changed nematode ecological functions. Increased precipitation may aid soil nematode community recovery.
... In this study, soil fungal Chao 1 richness and Shannon index significantly responded to the increased N deposition and precipitation. Soil fungal abundance was significantly altered by N enrichment and changes in precipitation (Jia et al., 2017). According to the researches, soil fungal communities have an elastic response to increased environmental changes. ...
The Qinghai-Tibetan Plateau is experiencing significant nitrogen (N) deposition and increased precipitation. Although changes in N deposition and precipitation may cause changes in the composition and diversity of plants, the relationships between plant diversity and soil microbial diversity still has not been fully researched. Thus, we conducted a field simulation experiment in an alpine meadow that included three N and two water (W) addition levels, as well as their interactions. The abbreviations of all treatments are shown below: CK, control; W, added water; N5, added 5 g N m -2 yr -1 ; N10, added 10 g N m -2 yr -1 ; N5W, added N5 and W; N10W, added N10 and W. The dominant
plant species belong to the Gramineae family and include Elymus dahuricus, Stipa capillata, Poa pratensis and Agropyron cristatum. One year later after N and water addition, the results indicated that soil pH decreased with N addition, and with a combination of N and W addition together. High rate of N addition significantly lowered plant diversity. For different plant functional groups, the relative abundance of grasses significantly increased, while the relative abundance of forbs significantly decreased under N10, N5W and N10W treatments. Under N10W treatment, the relative abundance of
legumes was significantly reduced, while the relative abundance of cyperaceae was significantly increased. W and N interactions significantly decreased soil bacterial and fungal diversity. N addition showed an indirect effect on the fungal diversity by directly affecting plant productivity. Water addition showed an indirect effect on bacterial diversity by directly affecting plant diversity. Soil bacterial diversity showed a positive correlation with plant diversity, while soil fungal diversity had no significant correlation with plant diversity, but had a negative correlation with plant productivity. It also indicates that the strength of feedbacks between aboveground and belowground biodiversity will vary
depending on which groups of soil biota are considered.
... Furthermore, water and N are major limiting factors controlling plant growth and abundance of soil organisms in arid ecosystems (Stursova et al. 2006;Zhang et al. 2015). Studies have shown that fungal communities are essential for regulating the functionality of grassland ecosystems (including biodegradation, soil nutrient availability, plant growth, diversity, and biomass) (Voriskova and Baldrian 2013), and their community structures are sensitive to change in resource availability (e.g., N fertilization and water) (Jia et al. 2017;Zhang et al. 2018a). N fertilization primarily influence fungal diversity and structure by altering plant community attributes such as aboveground plant productivity and plant community composition (Chen et al. 2018). ...
... For example, water availability can enhance the abundance of soil fungal communities by increasing soil pH . Although the interactive effects of nitrogen fertilization and altered precipitation on soil fungi have been reported in previous studies Jia et al. 2017;Li et al. 2018), the understanding why these tight plant-fungi linkages still persist under scenarios of increased N level and altered precipitation is lacking. ...
... Mycorrhizal fungi (e.g., hyphal expansion) can improve plant tolerance to decreased precipitation partly through increased rates of water flow from soil into host plants (Augé 2001). The increased precipitation directly affects soil fungal diversity (Jia et al. 2017) and leads to a modified effect of nitrogen on the soil microbiome (Zhang et al. 2015). For example, previous studies demonstrated that precipitation plays a vital role in regulating the response of soil fungal biomass , soil fungal diversity (Hawkes et al. 2011), and fungal community composition (Zhang et al. 2018b) to N supply. ...
Purpose
Fungi play an essential role in regulating the functioning of terrestrial ecosystems and are sensitive to climate change factors. Climate change incidents, such as N deposition and altered precipitation, create abiotic stress regarding the water use efficiency of soil and nutrient limitation impacting the activity of soil fungi. This study aimed to examine the combined effects of N fertilization and altered precipitation on soil fungal diversity and composition in the desert steppe.
Materials and methods
In the present study, we carried out a field experiment to assess the soil fungal diversity and composition of the desert steppe in response to N fertilizer (0 or 35 kg N ha⁻¹ year⁻¹) and precipitation changes (control, − 50% precipitation, or + 50% precipitation) in the desert steppe. The study was initiated in 2012, and plant and soil samples were collected after 5 years (August, 2017) of field treatments. High-throughput sequencing was applied to estimate the fungal diversity and composition.
Results and discussion
The soil fungal communities were dominated by Ascomycota (87.85% ± 1.26%), which primarily drove the fungal community composition. Decreased precipitation promoted strong shifts in fungal community composition under both N fertilizer levels. Increased precipitation significantly reduced Shannon-Wiener indices by 9.96%. The increasing relative abundances of fungal functional groups (lichenized saprotroph, animaland plant pathogens) resulted in a marked shift in fungal community composition from decreased precipitation to increased precipitation, which is attributed to the important role of the Ascomycota phylum in fungal communities. Structural equation modeling (SEM) indicated that C4 biomass was the predominant factor determining the Shannon-Wiener index for these fungi. Direct altered precipitation, indirect soil pH, and C4 biomass together controlled soil fungal community composition, with altered precipitation as the main driver.
Conclusions
The interactive effects of N fertilizer and altered precipitation on grassland plant density, biomass, and soil properties may play an essential role in determining fungal diversity and community composition. Precipitation is a primary limiting factor that influences fungal community composition. Effects of N fertilizer on soil fungal community composition are highly dependent on changes in precipitation.
... Nitrogen effects on richness of fungi were mediated by water application in the desert. Nitrogen addition plus water manipulation significantly shifted the relative abundances of cultivable fungi (Jia et al. 2017). In the 0-2 cm soil depth, enhanced fungal species richness was observed under N addition plus reduced water compared to only N addition treatments. ...
... In the 0-2 cm soil depth, enhanced fungal species richness was observed under N addition plus reduced water compared to only N addition treatments. However, the N addition with water treatments did not affect fungal diversity indices such as species richness, Shannon-Wiener index, or evenness at the soil depth of 0-30 cm (Jia et al. 2017). ...
In desert ecosystems, nitrogen (N) deposition can alter the soil N pools (soil available N or total N) or plant N uptake while rarely changing other nutrient contents. In this chapter, we reviewed the effects of N deposition on China’s desert ecosystems based on experimental results. Acidification of the soil and toxic effects on the microbes often occur under high N addition. Soil enzyme activities in response to N additions depended on the N applied rates and the specific enzyme types, with oxidative enzymes more stable than hydrolytic enzymes. Soil microbial biomass N was usually increased by N addition, while the responses of microbial biomass carbon depended on shrub existence. The soil microbial community structure was generally not affected by N addition, although increased soil bacterial phospholipid fatty acid (PLFA) and non-changes in soil fungal PLFAs were observed. For the greenhouse gas emission, N addition cannot shift the soil respiration except under high moisture condition. Positive effects of N input on nitrous oxide emission with no or negative methane uptake were found. The growth and biomass allocation of vascular plants under N addition depended on life-forms/species in desert ecosystems. The increased individual growth under N addition was not always observed in productivity because of changes in the community structure. With the increase in N added rates, abundance, richness, and density usually decreased, and the effects were affected by the years exposed to N addition. More water supply can expand the N effects on plant growth and diversity in desert ecosystems. Lower levels of N addition also stimulated growth of nonvascular plants (biocrusts), while higher levels exhibited negative effects.
... The desert steppe ecosystem of Inner Mongolia, which comprises 10.7% of the region's grassland, is important for both livestock production and preservation of biodiversity (Jia et al., 2017a). Grazing has been one of the most important land-use methods across all Inner Mongolian steppe types for thousands of years. ...
... The experiment was conducted in the Inner Mongolia Academy of Agricultural & Animal Husbandry Sciences, located in Shiziwang Banner (41°47'17" N, 111°53'46" E; 1450 m a.s.l.), Inner Mongolia Autonomous Region (IMAR), northern China ( Figure 1) (Lin et al., 2010b;Cao et al., 2013). The steppe is characterized by a semiarid continental monsoon climate with a short plant-growing period from May to September (Jia et al., 2017a). The mean annual temperature is 3.4 ℃, and the three highest monthly mean temperatures are 21.5, 24.0, 23.5 °C in June, July and August, respectively (Lin et al., 2010b). ...
Degradation and desertification are extremely significant environmental problems in arid and semi-arid grassland ecosystems. Long-term overgrazing is the most fundamental cause of grassland degradation. We investigated relationships between grazing intensity and bacterial communities in non-rhizospheric and rhizospheric soils in desert steppe, including 0-10, 10- 20 and 20-30 cm depth soils, as well as Stipa breviflora Griseb., Cleistogenes songorica (Roshev.) Ohwi, Artemisia frigida Willd. and plant community rhizospheric soils. This involved simulating grazing intensities in a long-term localization experiment, using a randomized block design. The effects of grazing on non-rhizospheric soil bacterial abundance were reflected in the 0-10 cm layer, increasing under light grazing and decreasing rapidly under moderate and heavy grazing, mainly related to Bacillus. Bacterial abundance in dominant plant rhizosphere responded differently. In A. frigida Willd. Rhizosphere, it decreased with increasing grazing intensity (a trend repeated in mixed rhizosphere). Bacterial abundance in S. breviflora and C. songorica rhizosphere increased under light and decreased under moderate and heavy grazing. Thus, changes in the dominant plant rhizospheric bacterial community did not significantly affect bacterial abundance in mixed rhizosphere. Changes in the rhizospheric bacterial abundance mainly resulted from levels of the dominant species, Streptomyces and Arthrobacter. There were significantly different results for bacterial community structure. Specifically, grazing had a nonsignificant and significant impact on bacterial community structures in non-rhizospheric (FPERMANOVA = 1.38, p = 0.199) and rhizospheric (FPERMANOVA = 2.03, p = 0.012) soil, respectively, varying significantly among plants (FPERMANOVA = 1.9, p = 0.022). In conclusion, bacterial communities in rhizosphere were mainly affected by plant species and were more sensitive to changing grazing intensity than in non-rhizospheric soil.
... To identify the effects of N supplementation and climate warming on soil ammonia-oxidizers, a long-term simulated experiment in the field was conducted in the desert steppe of northern China in 2006, which is an essential part of the Eurasian grassland biome that plays a vital role in livestock production and maintaining ecological balance. A previous study showed that the desert steppe ecosystem is fragile and sensitive to disturbances caused by climatic changes (Jia et al., 2017). In this study, we used quantitative polymerase chain reaction (PCR) analysis and Miseq sequencing to investigate these effects after 11 yr of consecutive field experiments with repeated ammonium nitrate (NH 4 NO 3 ) supplementation and simulated climate warming. ...
... Mean annual precipitation is ?280 mm, and ?70% of the total precipitation mainly occurs from June to September (Jia et al., 2017;Lin et al., 2010). Mean annual evaporation is about 2947 mm, and mean annual temperature is 6.7°C, with mean monthly temperature ranging from −11.6°C in January to 22.6°C in July. ...
... Five soil cores (10 cm depth, 2 cm diameter) were obtained from random locations in each subplot. Each soil core was divided into three layers (i.e., soil depths of 0-2 cm, 2-5 cm, and 5-10 cm) according to the results of Jia et al. (2017). After roots, gravel, and residues were removed, five soil cores were pooled into a composite sample for each soil depth of individual subplots. ...
Ammonia oxidation, the first and rate‐limiting step of the nitrification process, is driven by ammonia‐oxidizing archaea (AOA) and ammonia‐oxidizing bacteria (AOB). Numerous studies on the response of aboveground plant and soil microbial communities to climate change have been conducted, but the effects of climate warming and nitrogen (N) supplementation on the abundance, community composition, and diversity of AOA and AOB in arid and semiarid steppe ecosystem remain elusive. In this study, we examined these effects on soil samples from the Inner Mongolia desert steppe after 11 consecutive years of simulated climate warming and N supplementation (ammonium nitrate), using real‐time quantitative polymerase chain reaction analysis and high throughput sequencing technique. We observed that the amoA abundance of AOA outnumbered that of AOB in this desert steppe, with N supplementation having a significant effect on amoA abundance. The effect of climate warming on the amoA abundance of AOA or AOB depended on soil depth. Eleven years of simulated climate warming and N supplementation had varying effects on the amoA abundance of AOA and AOB. Nitrogen supplementation shifted ammonia‐oxidizing bacterial community structure, increased potential nitrification rates, and affected ammonia‐oxidizing microbial α diversity at topsoil. The dominating factors shaping AOB community structure among the treatments were NH4⁺–N, NO3⁻–N, and pH, whereas pH was the significant factor in shaping AOA community structure. Our results indicate that N supplementation might be the driving factor aiding oxidation of ammonia at topsoil of arid and semiarid steppe ecosystem.
... m layer. Every soil core was divided into five layers according to preliminary results (Jia et al., 2017), namely, 0.00-0.02, 0.02-0.05, ...
... m, and was lowest in the layer of 0.20-0.30 m; this is consistent with the results of the study on microbes by Liu (2014) and Jia et al. (2016Jia et al. ( , 2017 in the same plot. This phenomenon may strongly be associated with the shallow and dense root systems of the above-ground community and the high content of soil physical and chemical factors in the 0.00-0.10 ...
... This phenomenon may strongly be associated with the shallow and dense root systems of the above-ground community and the high content of soil physical and chemical factors in the 0.00-0.10 m layer, as detailed in Jia et al. (2017). ...
Soil microorganisms are influenced by climate change. However, the effect of climate change on soil cultivable bacteria are unclear. In this study, the composition and diversity of the soil cultivable bacterial community were explored by a dilution–plate method, PCR, and 16S rRNA sequencing in a desert steppe of northern China after repeated NH4NO3 amendments and precipitation manipulation for seven years. The experimental treatments were as follows: control (CK), N addition (+N), N addition plus water addition (+N+W), and N addition plus water reduction (+N-W). Among the treatment groups, 11 genera and 17 bacterial species were isolated. Nitrogen addition and precipitation manipulation significantly increased the number of cultivable bacteria in the 0.00-0.30 m layer compared to CK. Compared to +N treatment, the +N+W and +N–W treatments had no significant impact on the number of cultivable bacteria. Compared to the CK community, bacterial communities exposed to the other three treatments did not show shifts in the relative abundance of dominant genera and other cultivable bacteria, except for Pontibacter and Staphylococcus. The treatments +N+W and +N-W significantly modified the relative abundance of Pontibacter and Staphylococcus compared to the +N treatment. Available potassium and phosphorus, and moisture content contributed to the change in the composition of the cultivable bacterial community (p>0.05). Nitrogen addition and precipitation manipulation significantly decreased species richness in the 0.00-0.02 m layer, but they did not affect evenness and the Shannon-Wiener Index in the 0.00-0.30 m layer. This study provides insights into how the composition and diversity of the bacterial community is affected by climate change scenarios.
Variations of precipitation have great impacts on soil carbon cycle and decomposition of soil organic matter. Soil bacteria are crucial participants in regulating these ecological processes and vulnerable to altered precipitation. Studying the impacts of altered precipitation on soil bacterial community structure can provide a novel insight into the potential impacts of altered precipitation on soil carbon cycle and carbon storage of grassland. Therefore, soil bacterial community structure under a precipitation manipulation experiment was researched in a semi-arid desert grassland in Chinese Loess Plateau. Five precipitation levels, i.e., control, reduced and increased precipitation by 40% and 20%, respectively (referred here as CK, DP40, DP20, IP40, and IP20) were set. The results showed that soil bacterial alpha diversity and rare bacteria significantly changed with altered precipitation, but the dominant bacteria and soil bacterial beta diversity did not change, which may be ascribed to the ecological strategy of soil bacteria. The linear discriminate analysis (LDA) effect size (LEfSe) method found that major response patterns of soil bacteria to altered precipitation were resource-limited and drought-tolerant populations. In addition, increasing precipitation greatly promoted inter-species competition, while decreasing precipitation highly facilitated inter-species cooperation. These changes in species interaction can promote different distribution ratios of bacterial populations under different precipitation conditions. In structural equation model (SEM) analysis, with changes in precipitation, plant growth characteristics were found to be drivers of soil bacterial community composition, while soil properties were not. In conclusion, our results indicated that in desert grassland ecosystem, the sensitive of soil rare bacteria to altered precipitation was stronger than that of dominant taxa, which may be related to the ecological strategy of bacteria, species interaction, and precipitation-induced variations of plant growth characteristics.
