scholarly journals Effects of Grazing Exclusion on Biomass Growth and Species Diversity among Various Grassland Types of the Tibetan Plateau

2019 ◽  
Vol 11 (6) ◽  
pp. 1705 ◽  
Author(s):  
Suizi Wang ◽  
Jiangwen Fan ◽  
Yuzhe Li ◽  
Lin Huang
Keyword(s):  
Species Diversity ◽  
Plant Growth ◽  
Alpine Meadow ◽  
Management Strategies ◽  
Livestock Grazing ◽  
The Tibetan Plateau ◽  
Grazing Exclusion ◽  
Palatable Species ◽  
The Impact ◽  
Grassland Types

Livestock grazing is an important determinant of species diversity and plant growth. Overgrazing is identified as one of the most important disturbances resulting in grassland degradation. Although many restoration practices have been implemented, grazing exclusion is one of the most effective methods to restore degraded grasslands. We explored the impact of five years of grazing exclusion on plant growth and species diversity in four types of grasslands: temperate steppe (TS), swamp meadow (SM), alpine steppe (AS), and alpine meadow (AM). Our results showed that grazing exclusion increased plant height, coverage, biomass, and species diversity in all four grasslands. The aboveground biomass in AM (180.8%), TS (117.3%), and SW (105.9%) increased significantly more than AS (10.1%). Grazing exclusion in AM had the greatest effect on proportion of palatable species, and the increase in palatable species in AM was higher than that of the other grassland types significantly. Species diversity increased significantly within the enclosure in SM (23.9%) and AM (20.8%). Our results indicate that grazing exclusion is an effective management strategy to restore degraded grasslands and it works best in alpine meadow. This study contributes to the growing theoretical basis for grassland management strategies and has a significant effect on sustainable development for grassland resources and pastoral areas.

scholarly journals Effects of grazing on plant species diversity and above ground biomass in a Trans- Himalayan Rangeland

1970 ◽  
Vol 17 (1) ◽  
pp. 25-31 ◽  
Author(s):  
Anita Pokharel ◽  
Madhu Chhetri ◽  
Chiranjibi P Upadhyaya
Keyword(s):  
Species Diversity ◽  
Species Composition ◽  
Plant Species ◽  
Diversity Index ◽  
Livestock Grazing ◽  
Above Ground Biomass ◽  
Ground Biomass ◽  
Grazing Effect ◽  
Significant Difference ◽  
Palatable Species

Limited information is available on the species composition, above ground biomass and its relations to grazing in a trans-Himalayan rangeland. Its assessment is essential for long term conservation and management. In the present study, we compared species composition, phenology, diversity index and biomass between controlled (without grazing) and open (free grazing) plots to assess the effects of grazing in the selected experimental sites of Upper Mustang during July and November 2005. Species encountered were classified as high, medium, low and non palatable and in three life form categories-grasses, shrubs and forbs. The experimental sites are dominated by forbs (80%) followed by grasses (15%) and shrubs (5%). Disturbance caused by grazing affects the phenological characteristics of the plant community. Result also reveals that species diversity, maximum possible diversity, evenness and species richness was higher in the grazed plots during July and November. A comparison of the aboveground biomass in July showed that mean percentage biomass of high, medium and low palatable species is higher in ungrazed plots. In November, the percentage biomass of only medium palatable species was higher in ungrazed plots and rest of the category is higher in grazed plots. Significant difference in July, a peak growing seasons for most of the plant species in the region reveals that the pasture has impact of livestock grazing. Keywords: Biomass, diversity, grazing effect, rangeland, species Banko Janakari: A journal of forestry information for Nepal Vol.17(1) 2007 pp.25-31

The effects of multiple factors on spring meltwater erosion on an alpine meadow slope

2021 ◽  
Author(s):  
Xiaonan Shi ◽  
Fan Zhang ◽  
Li Wang
Keyword(s):  
Soil Erosion ◽  
Sediment Yield ◽  
Alpine Meadow ◽  
Alluvial Soil ◽  
Strong Impact ◽  
The Tibetan Plateau ◽  
Slope Gradient ◽  
Multiple Factors ◽  
Total Runoff ◽  
The Impact

<p>Serious soil erosion is observed during the spring because soil thawing coincides with the period of snowmelt and low meadow coverage at this time. Studies relating to soil erosion caused by spring meltwater are limited and controversial. In this study, a field experimental study was conducted in an alpine meadow slope in the Binggou watershed on the northern edge of the Tibetan Plateau to assess the impact of multiple factors on spring meltwater erosion. The multiple factors included three flow rates, four slope gradients, and three underlying surface conditions (meadow, disturbed meadow, and alluvial soil). An equal volume of concentrated meltwater flow was used in all experiments. The results showed that rapid melting at a high flow rate could accelerate soil erosion. The influence of the slope gradient on the amount of runoff was positively linear and the influence was relatively low. However, the slope gradient had a strong impact on soil erosion. The meadow could effectively reduce soil erosion, although when the meadow was disturbed, the total runoff increased by 60% and the sediment yield by a factor of 1.5. The total runoff from the alluvial soil doubled in comparison to the meadow, while the sediment yield increased nearly 7-fold. The findings of this study could be helpful to understand the characteristics and impact of multiple controlling factors of spring meltwater erosion. It also aims to provide a scientific basis for an improved management of alpine meadows as well as water and soil conservation activities in high-altitude cold regions.</p><p> </p>

scholarly journals High Recovery of Saplings after Severe Drought in Temperate Deciduous Forests

Forests ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 546 ◽  
Author(s):  
Mirela Beloiu ◽  
Reinhold Stahlmann ◽  
Carl Beierkuhnlein
Keyword(s):  
Drought Stress ◽  
Species Diversity ◽  
Tree Species ◽  
Management Strategies ◽  
Field Measurements ◽  
Species Interaction ◽  
Severe Drought ◽  
Crown Defoliation ◽  
Species Specific ◽  
The Impact

Drought episodes are predicted to increase their intensity and frequency globally, which will have a particular impact on forest vitality, productivity, and species distribution. However, the impact of tree species interaction on forest vulnerability to drought is not yet clear. This study aims to assess how deciduous saplings react to drought and whether tree species diversity can buffer the impact of drought stress on tree saplings. Based on field measurements of crown defoliation and species diversity, vulnerability, drought recovery, and species interaction were analyzed. Fieldwork was carried out in Central Eastern Germany in 2018 during the vegetation season and repeated in 2019. Ten random saplings were measured in each of the 218 plots (15 × 15 m) with 2051 saplings in total out of 41 tree species. We found that 65% of the saplings experienced defoliation during the drought of 2018, of which up to 13% showed complete defoliation. At the species level, Fagus sylvatica L. and Betula pendula Roth. saplings were less affected (<55%), whereas Carpinus betulus L., Sorbus aucuparia L., and Frangula alnus Mill. saplings were the most affected (≥85%). One year later, in 2019, C. betulus and S. aucuparia had a faster recovery rate than F. sylvatica, B. pendula, Quercus spp., and Crataegus spp. (p < 0.001). Furthermore, we showed that forest stands with high sapling species diversity had a reduced vitality under drought stress (p < 0.001), indicating a higher competition for resources. The study provides evidence that F. sylvatica saplings can withstand and survive to persistent drought. Species-specific responses to drought are essential to be considered for implementing adaptive forest management strategies to mitigate the impact of climate change.

scholarly journals Does Grazing Exclusion Improve Soil Carbon and Nitrogen Stocks in Alpine Grasslands on the Qinghai-Tibetan Plateau? A Meta-Analysis

2020 ◽  
Vol 12 (3) ◽  
pp. 977 ◽  
Author(s):  
Xiang Liu ◽  
Haiyan Sheng ◽  
Zhaoqi Wang ◽  
Zhiwen Ma ◽  
Xiaotao Huang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Alpine Meadow ◽  
Meta Analysis ◽  
C:N Ratio ◽  
Mean Annual Precipitation ◽  
Alpine Grasslands ◽  
Grazing Exclusion ◽  
Alpine Steppe ◽  
Soc Stock ◽  
Grassland Types

Grazing exclusion has been widely used to restore the degraded alpine grasslands on the Qinghai-Tibetan Plateau (QTP). However, the dynamics of soil organic carbon (SOC) and soil total nitrogen (STN) pools after grazing exclusion and their controlling factors are currently less understood in this region. Here, a meta-analysis was conducted to quantitatively assess the changes in SOC and STN stocks in topsoil (0–30 cm) following grazing exclusion in three major grassland types (alpine meadow, alpine steppe, and alpine desert steppe) on the QTP and to explore the potential factors controlling the effects of grazing exclusion on SOC and STN stocks. The results showed that overall, grazing exclusion significantly increased SOC stock by 16.5% and STN stock by 11.2%. Significant increases in both SOC and STN stocks were observed after grazing exclusion of alpine meadow. In contrast, grazing exclusion did not improve SOC and STN stocks in the other two grassland types. The difference in mean annual precipitation among grassland types was a likely reason for the different dynamics of SOC and STN stocks after grazing exclusion. The effect sizes of both SOC and STN stocks were positively related to the duration of grazing exclusion, and a positive relationship was detected between the effect size of SOC stock and that of STN stock, demonstrating that the dynamics of SOC and STN were closely coupled during the period of grazing exclusion. However, grazing exclusion had no impact on soil C:N ratio for all grassland types, indicating that soil C:N ratio was generally stable after grazing exclusion. Therefore, it is suggested that the increase in STN can support continuous SOC accumulation following grazing exclusion. In conclusion, the findings suggest that the effects of grazing exclusion on SOC and STN stocks differ among grassland types on the QTP, and grazing exclusion of alpine meadows may provide substantial opportunities for improving SOC and STN stocks in this region.

The role of grazing exclusion by fence in regulating vegetation characteristics and plant diversity in Mongolian rangelands

2020 ◽  
Author(s):  
Tong Guo
Keyword(s):  
Species Richness ◽  
Plant Diversity ◽  
Vegetation Cover ◽  
Grazing Management ◽  
Grazing Exclusion ◽  
Vegetation Characteristics ◽  
Mongolian Rangelands ◽  
The Impact ◽  
Management Effects ◽  
Grassland Types

&lt;p&gt;Grazing largely affects vegetation dynamic of grassland communities. An intensified grazing will likely lead to grassland degradation. Therefore, to restore degraded grasslands, grazing exclusion by fence might be very helpful. However, the direction and the strength of grazing management effects on vegetation characteristics and plant diversity are currently disputable. In addition, vegetation cover and species richness are often independently examined under different grazing regimes in typical studies. Diversity-cover relationship is not adequately detected in degraded grasslands.&lt;/p&gt;&lt;p&gt;In this study, I aim at understanding effects of grazing exclusion on vegetation characteristics, plant diversity and their relationship. For this, I performed a fencing experiment in three grassland types, namely meadow (since 2009), mountain steppe (since 2013) and dry steppe (since 2013) in Mongolia. Each of three grasslands was set by two treatments: grazing exclusion and freely grazing. Vegetation characteristics were mirrored by vegetation cover and height. Plant diversity was evaluated by indices of species richness, Shannon-Wiener diversity and Pielou evenness.&lt;/p&gt;&lt;p&gt;The empirical results show that grazing exclusion by fence generally increases vegetation height regardless of grassland types. On the other hand, the changing direction of vegetation cover caused by grazing exclusion is not consistent in three grasslands. Fencing decreases species richness and Shannon diversity. While Pielou evenness responds slightly to changes in grazing regimes. Greater species richness benefits an increment of vegetation cover independent of grazing treatments and grassland types.&lt;/p&gt;&lt;p&gt;This study fills the knowledge gap of grazing management effects on vegetation characteristics and plant diversity in Mongolian rangelands. The results clearly demonstrate that grazing exclusion by fence is not an efficient way to restore degraded grasslands. This will also allow to project the impact of changes in land use on ecosystem functioning.&lt;/p&gt;

scholarly journals Effects of Grazing Intensity on Plant-Soil C: N: P Stoichiometry with Precipitation Changes During the Growing Season in Desert Grassland

2021 ◽  
Author(s):  
Wei Yan ◽  
Fengling Shi ◽  
Tao Wan
Keyword(s):  
Species Diversity ◽  
Plant Growth ◽  
Grazing Intensity ◽  
Desert Grassland ◽  
C:N:P Stoichiometry ◽  
Soil C ◽  
Plant Soil ◽  
Heavy Grazing ◽  
Significant Difference ◽  
The Impact

Abstract Background and aimsHigh-intensity grazing in the Mongolian grassland has led to the general deterioration of biodiversity and ecosystem functioning. Although abundant evidence shows that grazing affects the structure and function of grassland ecosystems, research on the impact of precipitation, especially under drought and overgrazing. MethodsWe examined the effects of heavy grazing, moderate grazing and no grazing on plant communities; plant and soil C, N and P contents; and plant and soil C:N:P stoichiometry in the desert grassland in different years with different amounts of precipitation. ResultsThere was no significant difference in the species diversity between the grazing and no grazing treatment, while the no grazing treatment was significantly higher than the heavy grazing treatment. Compared with the amounts in the no grazing and moderate grazing treatments, the N and P contents of the plants in the heavy grazing treatment were the highest, and the N content of the soil increased. There was a positive correlation between precipitation and the N and P contents of plants and the C and N contents of the soil at 0-10 cm and 10-20 cm. ConclusionsOur study suggest that a large amount of precipitation of plant growth will drive changes in the community species diversity. Grazing promoted the flow of N between plants and the soil, especially under heavy grazing. Under grazing stress, plants maintain the potential of compensatory growth, and precipitation in the peak season of plant growth induces rapid growth, suggesting that precipitation is an important factor driving grazing ecosystems.

scholarly journals CO2, CH4 and N2O fluxes in an alpine meadow on the Tibetan Plateau as affected by N-addition and grazing exclusion

2020 ◽  
Vol 117 (1) ◽  
pp. 29-42 ◽  
Author(s):  
Caiyun Luo ◽  
Shiping Wang ◽  
Lirong Zhang ◽  
Andreas Wilkes ◽  
Liang Zhao ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Alpine Meadow ◽  
The Tibetan Plateau ◽  
N Addition ◽  
Grazing Exclusion ◽  
N2o Fluxes ◽  
Ch4 And N2o
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