Increased grazing intensities induce differentiation of the relationships between functional traits and aboveground plant biomass in shrub‐ and grass‐dominated community in desert steppe

Grassland ecosystems, an important component of the terrestrial environment, play an essential role in the global carbon cycle and balance. We considered four different grazing intensities on a Stipa breviflora desert steppe: heavy grazing (HG), moderate grazing (MG), light grazing (LG), and an area fenced to exclude livestock grazing as the Control (CK). The analyses of the aboveground biomass, litter, belowground biomass, soil organic carbon and soil light fraction organic carbon were utilised to study the organic carbon stock characteristics in the S. breviflora desert steppe under different grazing intensities. This is important to reveal the mechanisms of grazing impact on carbon processes in the desert steppe, and can provide a theoretical basis for conservation and utilisation of grassland resources. Results showed that the carbon stock was 11.98–44.51 g m–2 in aboveground biomass, 10.43–36.12 g m–2 in plant litters, and 502.30–804.31 g m–2 in belowground biomass (0–40 cm). It was significantly higher in CK than in MG and HG. The carbon stock at 0–40-cm soil depth was 7817.43–9694.16 g m–2, and it was significantly higher in LG than in CK and HG. The total carbon stock in the vegetation-soil system was 8342.14–10494.80 g m–2 under different grazing intensities, with the largest value in LG, followed by MG, CK, and HG. About 90.54–93.71% of the total carbon in grassland ecosystem was reserved in soil. The LG and MG intensities were beneficial to the accumulation of soil organic carbon stock. The soil light fraction organic carbon stock was 484.20–654.62 g m–2 and was the highest under LG intensity. The LG and MG intensities were beneficial for soil nutrient accumulation in the desert steppe.

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Direct and Indirect Effects of Precipitation Change and Nutrients Addition on Desert Steppe Productivity in Inner Mongolia, Northern China

10.21203/rs.3.rs-244027/v1 ◽

2021 ◽

Author(s):

Xinxin Guo ◽

Xiaoan Zuo ◽

Ping Yue ◽

Xiangyun Li ◽

Ya Hu

Keyword(s):

Species Diversity ◽

Functional Traits ◽

Structural Equation ◽

Matter Content ◽

Nutrient Addition ◽

Global Changes ◽

Leaf Nitrogen Content ◽

Dry Matter Content ◽

Desert Steppe ◽

Precipitation Changes

Abstract Background and Aims Global changes profoundly impact on structure and function of grassland ecosystem. However, it remains unclear on the mechanism of how multiple limiting resources affect plant community primary productivity (ANPP) in desert steppe.Methods Here, we conducted an experiment to examine the effects of precipitation changes (natural and ± 50% precipitation) and nutrient addition (=N: 0 g·m-2·yr-1; +N: N 10 g·m-2·yr-1; +NPK: N/P/K each for 10 g·m-2·yr-1) on species diversity, ANPP, functional traits and soil properties. We used structural equation model (SEM) to evaluate the effects of precipitation changes and nutrient addition on ANPP.Results Increased precipitation increased species diversity and ANPP under NPK addition, NPK addition increased ANPP under increased precipitation, and the interaction of precipitation changes and nutrient addition was significant for ANPP. Drought reduced plant height and leaf dry matter content (LDMC), but increased leaf nitrogen content (LNC). ANPP was positively correlated with species richness, abundance, height and LDMC, but negatively correlated with specific leaf area (SLA) and LNC. The SEM showed increased precipitation and nutrient addition directly increased ANPP. Altered precipitation indirectly affected ANPP through its effect on abundance and SLA, while nutrient addition indirectly affected ANPP only through its effect on abundance.Conclusion The combined limitations of precipitation and multiple nutrients deserves more attention in studying the effect of global changes on productivity in arid steppe. Our results highlight the importance of species diversity and functional traits in driving short-term responses of ANPP to environmental factors in desert steppe ecosystems.

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Mechanisms regulating spatial changes in grassland productivity following nutrient addition in northern China

The Rangeland Journal ◽

10.1071/rj18049 ◽

2019 ◽

Vol 41 (1) ◽

pp. 83

Author(s):

Na Zhao ◽

Xinqing Shao ◽

Chao Chen ◽

Jiangwen Fan ◽

Kun Wang

Keyword(s):

Functional Traits ◽

Plant Biomass ◽

Northern China ◽

Functional Trait ◽

Community Response ◽

Nutrient Addition ◽

Leymus Chinensis ◽

Ecosystem Functions ◽

Natural Grasslands ◽

Key Species

Plant biomass is the most fundamental component of ecosystems. The spatial stability of plant biomass is important, and the mechanisms regulating plant biomass spatial variability in variable environments are a central focus of ecology. However, they have rarely been explored. We conducted an experiment to test how diversity and functional traits affected variation in biomass and community response to nutrient availability in three plant communities: natural; forb, legume, and bunchgrass; and rhizomatous grass. We found that biomass stability rarely changed with increasing taxonomic species richness and functional group richness but declined with increasing Shannon–Weiner indices (the combination of richness and evenness) and functional trait diversity. However, differences in plant species composition generated different responses in both the amount and spatial variation of biomass following nutrient addition. Because rhizomatous grasses are weakly competitive in nutrient-poor conditions, interaction between resource-acquisitive (grass) and stress-tolerant (forb) species in the natural community conferred the greatest overall stability. The rapid nutrient acquisition ability of the rhizomatous grass Leymus chinensis was stimulated in nutrient-abundant conditions. The functional traits of this dominant species overrode the diversity interaction effects of the natural and forb, legume, and bunchgrass communities. This ultimately resulted in the rhizomatous grass community being the most stable. Community stability was strongly determined by a few key species, particularly rhizomatous grasses, rather than by the average response of all species, thereby supporting the mass ratio hypothesis. Our results indicated that rhizomatous grasses could provide vegetative productivity to reduce soil loss and prevent degradation of L. chinensis-dominant grassland. Thus, protecting specific species is critical for maintaining rangeland ecosystem functions. Moreover, the conservation importance of grasses, non-leguminous forbs, legumes, or even rare species could not be ignored. Maintaining stability mechanisms in natural grasslands is complex, and therefore, further studies need to focus on finding a unified mechanism that can regulate appreciable biomass variation under shifting environmental conditions.

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Effect of Different Grazing Intensities on the Spatial-Temporal Variability in Above-Ground Live Plant Biomass in North American Mixed Grasslands

Canadian Journal of Remote Sensing ◽

10.1080/07038992.2014.1009882 ◽

2014 ◽

Vol 40 (6) ◽

pp. 423-439 ◽

Cited By ~ 3

Author(s):

Ravinder Virk ◽

Scott W. Mitchell

Keyword(s):

North American ◽

Temporal Variability ◽

Plant Biomass ◽

Grazing Intensities ◽

Mixed Grasslands

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Microbial Dynamic Changes under Different Grazing Intensities in Growing Seasons of Desert Steppe

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.864-867.2635 ◽

2013 ◽

Vol 864-867 ◽

pp. 2635-2638

Author(s):

Jing He ◽

Ting Ting Yang ◽

Tao Shi ◽

Guo Zheng Yao

Keyword(s):

Soil Bacteria ◽

Measured Data ◽

Desert Steppe ◽

Dynamic Changes ◽

Soil Microbial ◽

Growing Seasons ◽

Grassland Ecosystems ◽

Ground Survey ◽

Grazing Intensities ◽

Microbial Dynamic

Soil microbial plays a very important role in the grassland ecosystems, but measured data is very lack. In this paper, based on the ground survey data microbial dynamic changes in growing seasons of Desert steppe in 2012 was estimated. The main conclusions are as follows: soil bacteria number began to increase in May, reached to highest value in July and then began to decrease. Actinomycetes population increased first and then decreased. Fungus amount decreased in beginning and then increased. Grazing significantly affect the number of soil microbial, shown as soil microbial of very severe grazing fences are significantly lower than other fences.

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Trade-off Strategy of Three Dominant Species in Grazing Exclusion of Desert Steppe,china

10.21203/rs.3.rs-929704/v1 ◽

2021 ◽

Author(s):

jingli ma ◽

Hongbin Ma ◽

Yao Zhou ◽

Qi Lu ◽

Yan Shen

Keyword(s):

Leaf Area ◽

Functional Traits ◽

Root Length ◽

Dominant Species ◽

Specific Root Length ◽

Desert Steppe ◽

Short Term ◽

Trade Off ◽

Grazing Exclusion ◽

Root Functional Traits

Abstract Background and AimsGrazing exclusion is a powerful measure to restore the ecological environment in desert steppe. Studying the changing trend of functional traits and trade-off strategy about dominant species what is of great significance to understand the effect of grazing exclusion on species succession. Methods We studied that the change of leaf and root functional traits of three dominant species (Lespedeza potaninii, Agropyron mongolicum and Stipa breviflora) under different term of grazing exclusion. ResultsWe found that the leaf area and leaf nitrogen content, leaf dry matter content, total root length, specific root length and specific root surface of Lespedeza potaninii in grazing were higher than grazing exclusion. The highest specific leaf area, specific root length of Agropyron mongolicum and Stipa breviflora were observed in short-term grazing exclusion. Leaf tissue density and root tissue density significantly decreased in short-term grazing exclusion. Economic spectrum exist, Lespedeza potaninii have more conservation strategy in short-term grazing exclusion compared with grazing. Agropyron mongolicum and Stipa breviflora have more acquisition strategy in grazing exclusion. Average diameters have great effected on above-ground biomass.ConclusionThe result showed that grazing exclusion change leaf and root functional traits of three dominant species, different species have different trade-off strategy.

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Do Invasive Earthworms Affect the Functional Traits of Native Plants?

Frontiers in Plant Science ◽

10.3389/fpls.2021.627573 ◽

2021 ◽

Vol 12 ◽

Author(s):

Lise Thouvenot ◽

Olga Ferlian ◽

Rémy Beugnon ◽

Tom Künne ◽

Alfred Lochner ◽

...

Keyword(s):

Functional Groups ◽

Plant Community ◽

Functional Traits ◽

North American ◽

Native Plants ◽

Plant Biomass ◽

Grass Species ◽

Earthworm Invasion ◽

Invasive Earthworms ◽

Community Changes

As ecosystem engineers, invasive earthworms are one of the main drivers of plant community changes in North American forests previously devoid of earthworms. One explanation for these community changes is the effects of earthworms on the reproduction, recruitment, and development of plant species. However, few studies have investigated functional trait responses of native plants to earthworm invasion to explain the mechanisms underlying community changes. In a mesocosm (Ecotron) experiment, we set up a plant community composed of two herb and two grass species commonly found in northern North American forests under two earthworm treatments (presence vs. absence). We measured earthworm effects on above- and belowground plant biomass and functional traits after 3 months of experiment. Our results showed that earthworm presence did not significantly affect plant community biomass and cover. Furthermore, only four out of the fifteen above- and belowground traits measured were affected by earthworm presence. While some traits, such as the production of ramets, the carbon and nitrogen content of leaves, responded similarly between and within functional groups in the presence or absence of earthworms, we observed opposite responses for other traits, such as height, specific leaf area, and root length within some functional groups in the presence of earthworms. Plant trait responses were thus species-specific, although the two grass species showed a more pronounced response to earthworm presence with changes in their leaf traits than herb species. Overall, earthworms affected some functional traits related to resource uptake abilities of plants and thus could change plant competition outcomes over time, which could be an explanation of plant community changes observed in invaded ecosystems.

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Increased Precipitation Shapes Relationship between Biochemical and Functional Traits of Stipa glareosa in Grass-Dominated Rather than Shrub-Dominated Community in a Desert Steppe

Plants ◽

10.3390/plants9111463 ◽

2020 ◽

Vol 9 (11) ◽

pp. 1463

Author(s):

Ya Hu ◽

Xiaoan Zuo ◽

Ping Yue ◽

Shenglong Zhao ◽

Xinxin Guo ◽

...

Keyword(s):

Superoxide Dismutase ◽

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Functional Traits ◽

Plant Communities ◽

Dry Matter Content ◽

Desert Steppe ◽

Biochemical Traits ◽

Shrub Community

Understanding the effects of precipitation variations on plant biochemical and functional traits is crucial to predict plant adaptation to future climate changes. The dominant species, Stipa glareosa, plays an important role in maintaining the structure and function of plant communities in the desert steppe, Inner Mongolia. However, little is known about how altered precipitation affects biochemical and functional traits of S. glareosa in different communities in the desert steppe. Here, we examined the responses of biochemical and functional traits of S. glareosa in shrub- and grass-dominated communities to experimentally increased precipitation (control, +20%, +40%, and +60%). We found that +40% and +60% increased plant height and leaf dry matter content (LDMC) and decreased specific leaf area (SLA) of S. glareosa in grass community. For biochemical traits in grass community, +60% decreased the contents of protein and chlorophyll b (Cb), while +40% increased the relative electrical conductivity and superoxide dismutase. Additionally, +20% increased LDMC and malondialaenyde, and decreased SLA and protein in shrub community. Chlorophyll a, Cb, carotenoids, protein and superoxide dismutase in the grass community differed with shrub community, while +60% caused differences in SLA, LDMC, leaf carbon content, malondialaenyde and peroxidase between two communities. The positive or negative linear patterns were observed between different functional and biochemical traits in grass- rather than shrub-community. Soil water content explained changes in some biochemical traits in the grass community, but not for functional traits. These results suggest that increased precipitation can affect functional traits of S. glareosa in the grass community by altering biochemical traits caused by soil water content. The biochemical and functional traits of S. glareosa were more sensitive to extreme precipitation in grass- than shrub-community in the desert steppe. Our study highlights the important differences in adaptive strategies of S. glareosa in different plant communities at the same site to precipitation changes.

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Precipitation Variability Affects Aboveground Biomass Directly and Indirectly via Plant Functional Traits in the Desert Steppe of Inner Mongolia, Northern China

Frontiers in Plant Science ◽

10.3389/fpls.2021.674527 ◽

2021 ◽

Vol 12 ◽

Author(s):

Huan Cheng ◽

Yuanbo Gong ◽

Xiaoan Zuo

Keyword(s):

Leaf Area ◽

Functional Traits ◽

Aboveground Biomass ◽

Inner Mongolia ◽

Structural Equation Models ◽

Plant Functional Traits ◽

Leaf Nitrogen Content ◽

Dry Matter Content ◽

Desert Steppe ◽

Precipitation Changes

Clarifying the response of community and dominance species to climate change is crucial for disentangling the mechanism of the ecosystem evolution and predicting the prospective dynamics of communities under the global climate scenario. We examined how precipitation changes affect community structure and aboveground biomass (AGB) according to manipulated precipitation experiments in the desert steppe of Inner Mongolia, China. Bayesian model and structural equation models (SEM) were used to test variation and causal relationship among precipitation, plant diversity, functional attributes, and AGB. The results showed that the responses of species richness, evenness, and plant community weighted means traits to precipitation changes in amount and year were significant. The SEM demonstrated that precipitation change in amount and year has a direct effect on richness, evenness, and community-weighted mean (CWM) for height, leaf area (LA), specific leaf area (SLA), leaf dry matter content (LDMC), leaf nitrogen content (LNC), and leaf carbon content (LCC) and AGB; there into CWM for height and LDMC had a direct positive effect on AGB; LA had a direct negative effect on AGB. Three dominant species showed diverse adaptation and resource utilization strategies in response to precipitation changes. A. polyrhizum showed an increase in height under the precipitation treatments that promoted AGB, whereas the AGB of P. harmala and S. glareosa was boosted through alterations in height and LA. Our results highlight the asynchronism of variation in community composition and structure, leaf functional traits in precipitation-AGB relationship. We proposed that altered AGB resulted from the direct and indirect effects of plant functional traits (plant height, LA, LDMC) rather than species diversity, plant functional traits are likely candidate traits, given that they are mechanistically linked to precipitation changes and affected aboveground biomass in a desert steppe.

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