Climate and anthropogenic drivers of changes in abundance of C4 annuals and perennials in grasslands on the Mongolian Plateau

Auerswald, K.; Gong, Xiaoping; Schnyder, H.; Bai, Yongfei; He, Jin‐Sheng

doi:10.1002/glr2.12019

Cited by 5 publications

(3 citation statements)

References 59 publications

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“…They found that increasing grazing intensity favoured stoloniferous plants, rosette formation likeliness, short height, and increased the abundance of short-lived and fast-growing species when climatic conditions and grazing history were both taken into consideration. Some findings of the above meta-analysis were partly confirmed for sheep-grazed pastures by Pettit et al (1995), Yang et al (2022) and Farmilo et al (2023). However, none of the above papers studied the biomass of life-and growth form groups along a gradient of grazing intensity in sheep grazed pastures.…”

Section: Introductionmentioning

confidence: 62%

High species richness of sheep-grazed sand pastures is driven by disturbance tolerant and weedy short-lived species

Kovacsics-Vári,

Sonkoly,

Tóth

et al. 2024

Preprint

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We selected 15 sheep-grazed sand pastures along increasing grazing intensity to study fine scale biomass patterns of main fractions (green biomass, litter) and that of plant species and functional groups (life forms and social behaviour types). We classified them into five grazing intensity levels based on stocking rate, proximity to drinking and resting places, and the number of droppings and other tracks of grazing animals. We formulated three study questions: i) How does increasing intensity of sheep grazing affect the amount of green biomass, species richness and their relationship in sand pastures? ii) How does increasing intensity of sheep grazing affect the biomass of perennial and short-lived graminoids and forbs? iii) How does disturbance value (expressed in the biomass ratio of disturbance tolerant and ruderal species) change along the gradient of grazing intensity? A unimodal relationship between green biomass and species richness was detected. Along the grazing intensity gradient, we found an increasing trend for species richness; significant differences for green biomass (decreasing trend) and litter (decreasing trend), moreover for graminoids (decreasing trend), and short-lived forbs (increasing trend). We found an increasing amount of disturbance tolerant and ruderal species with increasing grazing intensity. We concluded that stocking rate and proximity to drinking and resting places jointly affected vegetation and created an uneven pattern for composition and amount of biomass in all grazing intensity levels. Our findings might be instructive for pastures in densely populated regions which are prone to the encroachment of disturbance-tolerant and ruderal species.

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Section: Introductionmentioning

confidence: 62%

High species richness of sheep-grazed sand pastures is driven by disturbance tolerant and weedy short-lived species

Kovacsics-Vári,

Sonkoly,

Tóth

et al. 2024

Preprint

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“…These results indicate a reduced role for species interactions over plant communities in patchy degraded grasslands. An increase in abundance of annual plants is typical of grassland degradation (Chen et al, 2017) and contributes to the low stability of grassland ecosystems (Yang et al, 2022). The high abundance of annual plants induced by PD observed here is a further indication of the instability of patchy degraded grassland ecosystems.…”

Section: Discussionmentioning

confidence: 99%

Changes in plant community assembly from patchy degradation of grasslands and grazing by different‐sized herbivores

Song

et al. 2023

Ecological Applications

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Grassland degradation caused by increases in livestock grazing threatens a variety of ecosystem services. Understanding changes in plant community assembly during the process of grassland degradation in the presence of grazing is important to help restore degraded grasslands worldwide but has received little attention thus far. The grassland degradation process is typified by heterogeneous degradation, that is, gradual formation of degraded patches (hereafter “patchy degradation”). Here, we experimentally examined the effects of herbivore grazing and patchy degradation on plant community assembly using nine pairs of non‐degraded (intact) and patch‐degraded (fragmented) grasslands subject to grazing by different‐sized herbivores (i.e., NG, no grazing; SG, sheep grazing; CG, cattle grazing) over 4 years. Using a null‐model approach, we estimated the relative magnitude of deterministic processes of community assembly by comparing the observed and expected β‐diversity. We found that in the absence of herbivore grazing, deterministic processes played a greater role in community assembly, regardless of whether patchy degradation had occurred. However, the deterministic processes resulted in plant communities being more spatially similar in non‐degraded grasslands while being more dissimilar in patchy degraded grasslands. Compared with non‐degraded grasslands, species with strong competitive abilities (i.e., Leymus chinensis) were less dominant in patchy degraded grasslands, indicating relaxed competition and a reduced role of species interactions over plant communities. Instead, patchy degradation added the role of environmental variables over plant communities. SG consistently promoted more stochastic plant community assembly in both non‐degraded and patch‐degraded grasslands, while CG promoted more stochastic plant community assembly only in the non‐degraded state, having no effect in the patch‐degraded state. Our study offers important insights into changes in plant community assembly during ongoing patch‐degradation of grasslands, indicating the role of increased environmental filtering of soil and reduced species interactions in driving plant community dynamics with increasing grassland patchy degradation. We also uncovered an herbivore species‐specific effect on plant community assembly during the process of grassland degradation, which will better inform and improve future grassland restoration planning efforts.

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“…Third, plant roots in different soil layers often perform different functions with respect to water acquisition. Shallow roots typically absorb rainwater, while deep roots can absorb groundwater (Yang et al., 2022), and grassland plants can adjust the vertical distribution of their roots along a soil profile to adapt to drought or wet conditions (Zhang et al., 2019). Finally, soil microbes such as bacteria and fungi usually obtain carbon from plant roots and help plants acquire soil nutrients (Chen et al., 2015).…”

Section: Introductionmentioning

confidence: 99%

Changes in productivity partitioning induced by precipitation extremes increase inaccuracy of grassland carbon estimation

Sun,

Yan,

Zhang

et al. 2024

Global Change Biology

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The fraction of net primary productivity (NPP) allocated to belowground organs (fBNPP) in grasslands is a critical parameter in global carbon cycle models; moreover, understanding the effect of precipitation changes on this parameter is vital to accurately estimating carbon sequestration in grassland ecosystems. However, how fBNPP responds to temporal precipitation changes along a gradient from extreme drought to extreme wetness, remains unclear, mainly due to the lack of long‐term data of belowground net primary productivity (BNPP) and the fact that most precipitation experiments did not have a gradient from extreme drought to extreme wetness. Here, by conducting both a precipitation gradient experiment (100–500 mm) and a long‐term observational study (34 years) in the Inner Mongolia grassland, we showed that fBNPP decreased linearly along the precipitation gradient from extreme drought to extreme wetness due to stronger responses in aboveground NPP to drought and wet conditions than those of BNPP. Our further meta‐analysis in grasslands worldwide also indicated that fBNPP increased when precipitation decreased, and the vice versa. Such a consistent pattern of fBNPP response suggests that plants increase the belowground allocation with decreasing precipitation, while increase the aboveground allocation with increasing precipitation. Thus, the linearly decreasing response pattern in fBNPP should be incorporated into models that forecast carbon sequestration in grassland ecosystems; failure to do so will lead to underestimation of the carbon stock in drought years and overestimation of the carbon stock in wet years in grasslands.

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Climate and anthropogenic drivers of changes in abundance of C4 annuals and perennials in grasslands on the Mongolian Plateau

Cited by 5 publications

References 59 publications

High species richness of sheep-grazed sand pastures is driven by disturbance tolerant and weedy short-lived species

High species richness of sheep-grazed sand pastures is driven by disturbance tolerant and weedy short-lived species

Changes in plant community assembly from patchy degradation of grasslands and grazing by different‐sized herbivores

Changes in productivity partitioning induced by precipitation extremes increase inaccuracy of grassland carbon estimation

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