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Arroyo AI, Pueyo Y, Barrantes O, Alados CL. Interplay between Livestock Grazing and Aridity on the Ecological and Nutritional Value of Forage in Semi-arid Mediterranean Rangelands (NE Spain). Environ Manage 2024; 73:1005-1015. [PMID: 38300314 PMCID: PMC11024040 DOI: 10.1007/s00267-024-01939-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 01/13/2024] [Indexed: 02/02/2024]
Abstract
Rangeland-based livestock production constitutes a primary source of livelihood for many inhabitants of dryland regions. Their subsistence relies heavily on maintaining the productivity, biodiversity and services of these ecosystems. Harsh environmental conditions (e.g., drought) combined with land use intensification (e.g., overgrazing) make dryland ecosystems vulnerable and prone to degradation. However, the interplay between livestock grazing intensity and aridity conditions in driving the conservation and nutritional value of forage in arid and semi-arid rangelands is still not fully understood. In this study, we performed structural equation models (SEM) to assess the simultaneous direct and indirect effects of livestock grazing intensity and aridity level on community structure, diversity, biomass, forage production, forage C:N ratio and forage fiber composition in two semi-arid Mediterranean rangelands, NE Spain. Not surprisingly, we found that higher livestock grazing intensity led to lower community plant cover, especially when combined with higher aridity. However, both increasing grazing intensity and aridity were associated with higher forage production after one year of grazing exclusion. We did not find any adverse effect of livestock grazing on plant diversity, although plant species composition differed among grazing intensity levels. On the other hand, we found an aridity-driven trade-off in regard of the nutritional value of forage. Specifically, higher aridity was associated with a decrease in the least digestible fiber fraction (i.e., lignin) and an increase in forage C:N ratio. More interestingly, we found that livestock grazing modulated this trade-off by improving the overall forage nutritional value. Altogether, our results provide further insights into the management of semi-arid Mediterranean rangelands, pointing out that maintaining traditional rangeland-based livestock production may be a sustainable option as long as rangeland conservation (e.g., community plant cover) is not severely compromised.
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Affiliation(s)
- Antonio I Arroyo
- Instituto Pirenaico de Ecología (IPE), CSIC, Av. Montañana 1005, 50059, Zaragoza, Spain.
| | - Yolanda Pueyo
- Instituto Pirenaico de Ecología (IPE), CSIC, Av. Montañana 1005, 50059, Zaragoza, Spain
| | - Olivia Barrantes
- Departamento de Ciencias Agrarias y del Medio Natural, Facultad de Veterinaria (Universidad de Zaragoza), C/ Miguel Servet 177, 50013, Zaragoza, Spain
- Instituto Agroalimentario de Aragón -IA2- (CITA-Universidad de Zaragoza), C/ Miguel Servet 177, 50013, Zaragoza, Spain
| | - Concepción L Alados
- Instituto Pirenaico de Ecología (IPE), CSIC, Av. Montañana 1005, 50059, Zaragoza, Spain
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Jiang A, Mipam TD, Jing L, Li Z, Li T, Liu J, Tian L. Large herbivore grazing accelerates litter decomposition in terrestrial ecosystems. Sci Total Environ 2024; 922:171288. [PMID: 38423309 DOI: 10.1016/j.scitotenv.2024.171288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Revised: 02/20/2024] [Accepted: 02/24/2024] [Indexed: 03/02/2024]
Abstract
Plant litter decomposition is critical for carbon and nutrient cycling globally. However, the effect of large herbivore grazing on litter decomposition and its mechanisms remain less explored. Here, 1203 paired observations and 381 independent experiments were analyzed to determine how litter decomposition and nutrient cycling respond to changes in grazing intensity. Grazing significantly increased litter decomposition rate by 14.08 % and litter carbon release by 5.03 %, and this effect was observed in grasslands and croplands but not in forests. The positive grazing effect was also found under sheep and cattle/yak grazing. Moderate grazing advanced the home-field advantage effect but inhibited under heavy grazing for grazed litters. The grazing effect was larger for high quality litter than for low quality litter. Litter decomposition slowed under >10 years heavy grazing but accelerated under moderate grazing. The effects of large herbivore grazing on litter decomposition were jointly influenced by grazing intensity, livestock type, climate condition, decomposition duration, litter quality, and soil properties. Our results demonstrated that large herbivore grazing accelerates litter decomposition globally and emphasized the significance and importance of grazing intensity on litter decomposition, which should be integrated into terrestrial ecosystem models.
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Affiliation(s)
- Ao Jiang
- Sichuan Zoige Alpine Wetland Ecosystem National Observation and Research Station, Key Laboratory for Bio-resource and Eco-environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610064, China
| | - Tserang Donko Mipam
- Sichuan Zoige Alpine Wetland Ecosystem National Observation and Research Station, Institute of Qinghai-Tibetan Plateau, Southwest Minzu University, Chengdu 610041, China
| | - Luhuai Jing
- Sichuan Zoige Alpine Wetland Ecosystem National Observation and Research Station, Key Laboratory for Bio-resource and Eco-environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610064, China
| | - Zhe Li
- Sichuan Zoige Alpine Wetland Ecosystem National Observation and Research Station, Key Laboratory for Bio-resource and Eco-environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610064, China
| | - Tao Li
- Sichuan Zoige Alpine Wetland Ecosystem National Observation and Research Station, Key Laboratory for Bio-resource and Eco-environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610064, China
| | - Jianquan Liu
- Sichuan Zoige Alpine Wetland Ecosystem National Observation and Research Station, Key Laboratory for Bio-resource and Eco-environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610064, China
| | - Liming Tian
- Sichuan Zoige Alpine Wetland Ecosystem National Observation and Research Station, Key Laboratory for Bio-resource and Eco-environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610064, China.
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Usman M, Li L, Wang M, Wang Z, Hu A, Shi L, Hou F. Response of microbial communities to the changes in grazing intensity and season in a typical steppe. Environ Res 2024; 246:118126. [PMID: 38199463 DOI: 10.1016/j.envres.2024.118126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 12/01/2023] [Accepted: 01/05/2024] [Indexed: 01/12/2024]
Abstract
Livestock grazing is an influencing factor playing a key role in shaping the plant community, microbial community, and soil properties in grassland ecosystems. Northern China's Loess Plateau has been used for livestock grazing for centuries and is a vulnerable ecosystem. In this study, the fates of bacterial and fungal communities of the typical steppe of the Loess Plateau were investigated under increasing grazing intensities practiced in summer and winter seasons. The results revealed changes in soil physiochemical properties, plant community properties, and microbial diversity in response to alterations in the grazing intensity. The alpha diversity of microbial communities (including bacteria and fungi) exhibited an uneven trend during summer grazing due to an increase in grazing intensity, but it decreased during winter grazing; however, the observed changes were not significant. The beta diversity of the bacterial community was highly influenced by grazing intensity, the summer community clustered near nongrazing, and the winter community presented significantly different results. The beta diversity of the fungal community was not influenced by grazing intensity or season. Grazing induced the growth of fast-growing bacteria (such as Actinobacteria and Firmicutes) and saprophytic fungi and a reduction in overall pathogenic traits. Co-occurrence network analysis and a structural equation model revealed changes in soil and plant properties (such as soil nitrogen level, soil organic carbon level, aboveground biomass, and litter biomass), with an increase in grazing intensity contributing to alterations in bacterial and fungal diversities. This finding demonstrates that grazing intensity can directly affect soil microbes and play an indirect role by modifying soil nutrients and reducing plant biomass, which eventually contributes to changes in microbial communities. Overall, implementing low grazing intensity is suggested for maintaining the microbial community structure the same as that of the native microbiome (ungrazed) in the steppe ecosystems.
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Affiliation(s)
- Muhammad Usman
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs, Engineering Technology Research Center for Ecological Restoration and Utilization of Degraded Grassland in Northwest China, National Forestry and Grassland Administration, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, China
| | - Lan Li
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs, Engineering Technology Research Center for Ecological Restoration and Utilization of Degraded Grassland in Northwest China, National Forestry and Grassland Administration, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, China
| | - Mengyuan Wang
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs, Engineering Technology Research Center for Ecological Restoration and Utilization of Degraded Grassland in Northwest China, National Forestry and Grassland Administration, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, China
| | - Zhen Wang
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs, Engineering Technology Research Center for Ecological Restoration and Utilization of Degraded Grassland in Northwest China, National Forestry and Grassland Administration, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, China
| | - An Hu
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs, Engineering Technology Research Center for Ecological Restoration and Utilization of Degraded Grassland in Northwest China, National Forestry and Grassland Administration, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, China
| | - Liyuan Shi
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs, Engineering Technology Research Center for Ecological Restoration and Utilization of Degraded Grassland in Northwest China, National Forestry and Grassland Administration, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, China
| | - Fujiang Hou
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs, Engineering Technology Research Center for Ecological Restoration and Utilization of Degraded Grassland in Northwest China, National Forestry and Grassland Administration, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, China.
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Wang X, Zhou C, Zuo S, Ji Y, Liu W, Huang D. Heavy grazing reduces soil bacterial diversity by increasing soil pH in a semi-arid steppe. PeerJ 2024; 12:e17031. [PMID: 38464755 PMCID: PMC10924786 DOI: 10.7717/peerj.17031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 02/07/2024] [Indexed: 03/12/2024] Open
Abstract
Background In a context of long-term highly intensive grazing in grassland ecosystems, a better understanding of how quickly belowground biodiversity responds to grazing is required, especially for soil microbial diversity. Methods In this study, we conducted a grazing experiment which included the CK (no grazing with a fenced enclosure undisturbed by livestock), light and heavy grazing treatments in a desert steppe in Inner Mongolia, China. Microbial diversity and soil chemical properties (i.e., pH value, organic carbon, inorganic nitrogen (IN, NH 4 + -N and NO 3 - -N), total carbon, nitrogen, phosphorus, and available phosphorus content) both in rhizosphere and non-rhizosphere soils were analyzed to explore the responses of microbial diversity to grazing intensity and the underlying mechanisms. Results The results showed that heavy grazing only deceased bacterial diversity in the non-rhizosphere soil, but had no any significant effects on fungal diversity regardless of rhizosphere or non-rhizosphere soils. Bacterial diversity in the rhizosphere soil was higher than that of non-rhizosphere soil only in the heavy grazing treatment. Also, heavy grazing significantly increased soil pH value but deceased NH4+-N and available phosphorus in the non-rhizosphere soil. Spearman correlation analysis showed that soil pH value was significantly negatively correlated with the bacterial diversity in the non-rhizosphere soil. Combined, our results suggest that heavy grazing decreased soil bacterial diversity in the non-rhizosphere soil by increasing soil pH value, which may be due to the accumulation of dung and urine from livestock. Our results highlight that soil pH value may be the main factor driving soil microbial diversity in grazing ecosystems, and these results can provide scientific basis for grassland management and ecological restoration in arid and semi-arid area.
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Affiliation(s)
- Xiaonan Wang
- College of Grassland Science and Technology, China Agricultural University, Beijing, China
| | - Chengyang Zhou
- College of Grassland Science and Technology, China Agricultural University, Beijing, China
| | - Shining Zuo
- College of Grassland Science and Technology, China Agricultural University, Beijing, China
| | - Yixin Ji
- College of Grassland Science and Technology, China Agricultural University, Beijing, China
| | - Wenxin Liu
- College of Grassland Science and Technology, China Agricultural University, Beijing, China
| | - Ding Huang
- College of Grassland Science and Technology, China Agricultural University, Beijing, China
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5
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Wang M, Zhang C, Chen S, Zhang Y, Yu T, Xue X, Wu L, Zhou W, Yun X, Yan R, Bai K. Moderate grazing increased carbon, nitrogen and phosphorus storage in plants and soil in the Eurasian meadow steppe ecosystem. Sci Total Environ 2024; 914:169864. [PMID: 38185148 DOI: 10.1016/j.scitotenv.2023.169864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 12/22/2023] [Accepted: 12/31/2023] [Indexed: 01/09/2024]
Abstract
The effects of grazing on the cycling of carbon (C), nitrogen (N) and phosphorus (P) in grassland ecosystems are complex. Uncertainty still exists as regards the allocation of C, N and P storage amounts in grazed ecosystems in Inner Mongolia, situated at the eastern end of the Eurasian dryland. Based on the long-term cattle grazing experimental platform in the Hulun Buir meadow steppe of Inner Mongolia, a 3-year (2019-2021) field control experiment was conducted to assess how the grazing intensity influenced the quantities of C, N and P stored in canopy biomass, root, litter and soil compartments. We examined the relationships between the different pools and their regulatory pathways at the ecosystem level across six grazing intensities. In general, grazing increased the aboveground N and P contents but decreased the aboveground biomass C content and nutrient storage amounts in aboveground biomass, roots and litter. The grazing intensity of 0.34 AU ha-1 increased soil organic carbon, total nitrogen and total phosphorus storage amounts, with the soil accounting for 98 % of total reserves on average. Grazing affected soil pH, nutrient contents, above- and belowground biomass and soil environmental factors such as soil bulk density, which in turn affected C, N and P storage in the ecosystem according to the results of the structural equation model; therefore, grazing intensity can be an important factor regulating the input and output of nutrients in the ecosystem. In the future, for adaptive management of grasslands, moderate grazing could effectively increase C, N and P storage in meadow steppe ecosystems and ensure the nutrient balance and long-term sustainable development.
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Affiliation(s)
- Miao Wang
- State Key Laboratory of Efficient Utilization of Arid and Semiarid Arable Land in Northern China/Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, No. 12, Zhonguancun South Street, Haidian District, Beijing 100081, China; Beijing Digital Agriculture Rural Promotion Center, Building 3, No. 7 Beisha Beach, Chaoyang District, Beijing 100083, China
| | - Chu Zhang
- State Key Laboratory of Efficient Utilization of Arid and Semiarid Arable Land in Northern China/Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, No. 12, Zhonguancun South Street, Haidian District, Beijing 100081, China
| | - Sisi Chen
- State Key Laboratory of Efficient Utilization of Arid and Semiarid Arable Land in Northern China/Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, No. 12, Zhonguancun South Street, Haidian District, Beijing 100081, China
| | - Yu Zhang
- Institute of Grassland Science, Northeast Normal University, Changchun 130024, China
| | - Tianqi Yu
- State Key Laboratory of Efficient Utilization of Arid and Semiarid Arable Land in Northern China/Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, No. 12, Zhonguancun South Street, Haidian District, Beijing 100081, China
| | - Xiaojuan Xue
- Beijing Digital Agriculture Rural Promotion Center, Building 3, No. 7 Beisha Beach, Chaoyang District, Beijing 100083, China
| | - Lianhai Wu
- Net Zero and Resilient Farming, Rothamsted Research, Okehampton EX20 2SB, UK
| | - Wenneng Zhou
- School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, China
| | - Xiangjun Yun
- Grassland Research Institute, Chinese Academy of Agriculture Sciences, Hohhot 010010, China
| | - Ruirui Yan
- State Key Laboratory of Efficient Utilization of Arid and Semiarid Arable Land in Northern China/Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, No. 12, Zhonguancun South Street, Haidian District, Beijing 100081, China.
| | - Keyu Bai
- State Key Laboratory of Efficient Utilization of Arid and Semiarid Arable Land in Northern China/Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, No. 12, Zhonguancun South Street, Haidian District, Beijing 100081, China.
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6
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McDonald SE, Badgery W, Clarendon S, Orgill S, Sinclair K, Meyer R, Butchart DB, Eckard R, Rowlings D, Grace P, Doran-Browne N, Harden S, Macdonald A, Wellington M, Pachas ANA, Eisner R, Amidy M, Harrison MT. Grazing management for soil carbon in Australia: A review. J Environ Manage 2023; 347:119146. [PMID: 37852027 DOI: 10.1016/j.jenvman.2023.119146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 08/23/2023] [Accepted: 09/22/2023] [Indexed: 10/20/2023]
Abstract
The livestock industry accounts for a considerable proportion of agricultural greenhouse gas emissions, and in response, the Australian red meat industry has committed to an aspirational target of net-zero emissions by 2030. Increasing soil carbon storage in grazing lands has been identified as one method to help achieve this, while also potentially improving production and provision of other ecosystem services. This review examined the effects of grazing management on soil carbon and factors that drive soil carbon sequestration in Australia. A systematic literature search and meta-analysis was used to compare effects of stocking intensity (stocking rate or utilisation) and stocking method (i.e, continuous, rotational or seasonal grazing systems) on soil organic carbon, pasture herbage mass, plant growth and ground cover. Impacts on below ground biomass, soil nitrogen and soil structure are also discussed. Overall, no significant impact of stocking intensity or method on soil carbon sequestration in Australia was found, although lower stocking intensity and incorporating periods of rest into grazing systems (rotational grazing) had positive effects on herbage mass and ground cover compared with higher stocking intensity or continuous grazing. Minimal impact of grazing management on pasture growth rate and below-ground biomass has been reported in Australia. However, these factors improved with grazing intensity or rotational grazing in some circumstances. While there is a lack of evidence in Australia that grazing management directly increases soil carbon, this meta-analysis indicated that grazing management practices have potential to benefit the drivers of soil carbon sequestration by increasing above and below-ground plant production, maintaining a higher residual biomass, and promoting productive perennial pasture species. Specific recommendations for future research and management are provided in the paper.
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Affiliation(s)
- Sarah E McDonald
- NSW Department of Primary Industries, Trangie Agricultural Research Centre, Trangie, NSW, 2823, Australia.
| | - Warwick Badgery
- NSW Department of Primary Industries, Orange Agricultural Institute, 1447 Forest Rd, Orange, NSW, 2800, Australia
| | - Simon Clarendon
- NSW Department of Primary Industries, Tamworth Agricultural Institute, Tamworth, NSW, 2340, Australia
| | - Susan Orgill
- Select Carbon, 275 George St, Brisbane, Qld, 4000, Australia
| | - Katrina Sinclair
- NSW Department of Primary Industries, Wollongbar Agricultural Institute, Wollongbar, NSW, 2477, Australia
| | - Rachelle Meyer
- School of Agriculture and Food, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Dominique Bowen Butchart
- Tasmanian Institute of Agriculture, University of Tasmania, Newnham, Launceston, 7248, Australia
| | - Richard Eckard
- School of Agriculture and Food, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - David Rowlings
- Centre for Agriculture and the Bioeconomy, Queensland University of Technology, Brisbane, QLD, Australia
| | - Peter Grace
- Centre for Agriculture and the Bioeconomy, Queensland University of Technology, Brisbane, QLD, Australia
| | | | - Steven Harden
- NSW Department of Primary Industries, Tamworth Agricultural Institute, Tamworth, NSW, 2340, Australia
| | - Ainslie Macdonald
- School of Agriculture and Food, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Michael Wellington
- Centre for Entrepreneurial Agri-Technology, Australian National University, 116 Daley Rd, Acton, Australia
| | | | - Rowan Eisner
- Tasmanian Institute of Agriculture, University of Tasmania, Newnham, Launceston, 7248, Australia
| | - Martin Amidy
- Centre for Entrepreneurial Agri-Technology, Australian National University, 116 Daley Rd, Acton, Australia
| | - Matthew Tom Harrison
- Tasmanian Institute of Agriculture, University of Tasmania, Newnham, Launceston, 7248, Australia
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Wang Z, Tang K, Struik PC, Ashraf MN, Zhang T, Zhao Y, Wu R, Jin K, Li Y. Alteration of microbial carbon and nitrogen metabolism within the soil metagenome with grazing intensity at semiarid steppe. J Environ Manage 2023; 347:119078. [PMID: 37757683 DOI: 10.1016/j.jenvman.2023.119078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 07/02/2023] [Accepted: 08/30/2023] [Indexed: 09/29/2023]
Abstract
Grazing causes changes in microbiome metabolic pathways affecting plant growth and soil physicochemical properties. However, how grazing intensity affects microbial processes is poorly understood. In semiarid steppe grassland in northern China, shotgun metagenome sequencing was used to investigate variations in soil carbon (C) and nitrogen (N) cycling-related genes after six years of the following grazing intensities: G0, control, no grazing; G1, 170 sheep days ha-1 year-1; G2, 340 sheep days ha-1 year-1; and G3, 510 sheep days ha-1 year-1. Taxa and functions of the soil microbiome associated with the C cycle decreased with increasing grazing intensity. Abundances of genes involved in C fixation and organic matter decomposition were altered in grazed sites, which could effects on vegetation decomposition and soil dissolved organic carbon (DOC) content. Compared with the control, the abundances of nitrification genes were higher in G1, but the abundances of N reduction and denitrification genes were lower, suggesting that light grazing promoted nitrification, inhibited denitrification, and increased soil NO3- content. Q-PCR further revealed that the copies of genes responsible for carbon fixation (cbbL) and denitrification (norB) decreased with increasing grazing intensity. The highest copy numbers of the nitrification genes AOA and AOB were in G1, whereas copy numbers of the denitrification gene nirK were the lowest. A multivariate regression tree indicated that changes in C fixation genes were linked to changes in soil DOC content, whereas soil NO3- content was linked with nitrification and denitrification under grazing. Thus, genes associated with C fixation and the N cycle affected how C fixation and N storage influenced soil physicochemical properties under grazing. The findings indicate that grazing intensity affected C and N metabolism. Proper grassland management regimes (e.g., G1) are beneficial to the balances between ecological protection of grasslands and plant production in the semiarid steppe.
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Affiliation(s)
- Zhen Wang
- Grassland Research Institute, Chinese Academy of Agricultural Sciences, Hohhot, 010010, China; Key Laboratory of Grassland Ecology and Restoration of Ministry of Agriculture, Hohhot, 010010, China
| | - Kai Tang
- Institute for Applied and Environmental Microbiology, College of Life Science, Inner Mongolia Agricultural University, Hohhot, 010018, China
| | - Paul C Struik
- Centre for Crop Systems Analysis, Wageningen University & Research, Wageningen, the Netherlands
| | - Muhammad Nadeem Ashraf
- Institute of Soil and Environmental Sciences, University of Agriculture, Faisalabad, 38000, Pakistan
| | - Tongrui Zhang
- Grassland Research Institute, Chinese Academy of Agricultural Sciences, Hohhot, 010010, China
| | - Yanning Zhao
- Grassland Research Institute, Chinese Academy of Agricultural Sciences, Hohhot, 010010, China
| | - Riliga Wu
- Grassland Research Institute, Chinese Academy of Agricultural Sciences, Hohhot, 010010, China; Key Laboratory of Grassland Ecology and Restoration of Ministry of Agriculture, Hohhot, 010010, China
| | - Ke Jin
- Grassland Research Institute, Chinese Academy of Agricultural Sciences, Hohhot, 010010, China.
| | - Yuanheng Li
- Grassland Research Institute, Chinese Academy of Agricultural Sciences, Hohhot, 010010, China.
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8
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Ren S, Cao Y, Li J. Nitrogen availability constrains grassland plant diversity in response to grazing. Sci Total Environ 2023; 896:165273. [PMID: 37406710 DOI: 10.1016/j.scitotenv.2023.165273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Revised: 06/30/2023] [Accepted: 07/01/2023] [Indexed: 07/07/2023]
Abstract
Grassland plant diversity has been observed with divergent responses in grazing experiments around the world. However, the dominant role of nitrogen (N) availability in controlling this global variation has not been well explored, impeding our capacity to formulate effective strategies for preserving grassland plant diversity. Here, we synthesized data from 306 grazing experiments that measured plant diversity and soil N content across global grasslands. Overall, grazing reduced plant diversity by 7.63 %, with substantial variations observed across the dataset. Our study revealed that these contrasting effects were best explained by soil N change. Plant diversity under enhanced soil N showed a strong increase in response to grazing. We found that lower grazing intensity and higher background N deposition could collectively enhance soil N, thereby promoting diversity. These results suggest that while avoiding high grazing intensity is crucial in maintaining biodiversity of grazed grasslands, it alone is not sufficient. In regions with lower N deposition (< 500 mg N m-2 yr-1), additional management strategies that target improving soil fertility are needed. Our analysis propounds that local environmental conditions should be incorporated into decision-making of grassland biodiversity conservation, or ignoring this may lead to counterproductive impacts.
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Affiliation(s)
- Shuai Ren
- State Key Laboratory of Tibetan Plateau Earth System and Resources Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China.
| | - Yingfang Cao
- State Key Laboratory of Tibetan Plateau Earth System and Resources Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Juan Li
- Center for the Pan-Third Pole Environment, Lanzhou University, Lanzhou, China
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9
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Xu H, You C, Tan B, Xu L, Liu Y, Wang M, Xu Z, Sardans J, Peñuelas J. Effects of livestock grazing on the relationships between soil microbial community and soil carbon in grassland ecosystems. Sci Total Environ 2023; 881:163416. [PMID: 37059137 DOI: 10.1016/j.scitotenv.2023.163416] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 03/23/2023] [Accepted: 04/06/2023] [Indexed: 06/01/2023]
Abstract
Livestock grazing of grassland ecosystems may induce shifts in microbe community traits and soil carbon (C) cycling; however, impacts of grassland management (grazing) on soil C- microbe community trait (microbial biomass, diversity, community structure, and enzyme activity) relationships are unclear. To address this, we conducted a global meta-analysis of 95 articles of livestock grazing studies that vary in grazing intensities (light, moderate, and high) and durations (<5 years, 5-10 years, and > 10 years). We found that gazing decreased soil organic carbon content (SOC; 10.1 %), and activities of the enzymes of saccharase (SA; 31.1 %), urease (UA; 7.0 %), and acid phosphatase (11.9 %) in topsoil. Meanwhile, the SOC, soil microbial biomass and enzyme activities consistently decreased as grazing intensity and duration prolonged. Furthermore, we observed strong linear relationships of microbe community traits with SOC (p < 0.05), but weak relationships with soil N or P (p > 0.05) in grasslands, which also depends on the grazing intensity and duration. In conclusion, our results indicate that traits of soil carbon content, soil microbe community, and in particular their relationships in global grasslands are overall significantly affected by livestock grazing, but the effects strongly depend on the grazing intensity and duration.
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Affiliation(s)
- Hongwei Xu
- National Forestry and Grassland Administration Key Laboratory of Forest Resources Conservation and Ecological Safety on the Upper Reaches of the Yangtze River & Forestry Ecological Engineering in the Upper Reaches of the Yangtze River Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, China
| | - Chengming You
- National Forestry and Grassland Administration Key Laboratory of Forest Resources Conservation and Ecological Safety on the Upper Reaches of the Yangtze River & Forestry Ecological Engineering in the Upper Reaches of the Yangtze River Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, China
| | - Bo Tan
- National Forestry and Grassland Administration Key Laboratory of Forest Resources Conservation and Ecological Safety on the Upper Reaches of the Yangtze River & Forestry Ecological Engineering in the Upper Reaches of the Yangtze River Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, China
| | - Lin Xu
- National Forestry and Grassland Administration Key Laboratory of Forest Resources Conservation and Ecological Safety on the Upper Reaches of the Yangtze River & Forestry Ecological Engineering in the Upper Reaches of the Yangtze River Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, China
| | - Yang Liu
- National Forestry and Grassland Administration Key Laboratory of Forest Resources Conservation and Ecological Safety on the Upper Reaches of the Yangtze River & Forestry Ecological Engineering in the Upper Reaches of the Yangtze River Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, China
| | - Minggang Wang
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, Beijing, China.
| | - Zhenfeng Xu
- National Forestry and Grassland Administration Key Laboratory of Forest Resources Conservation and Ecological Safety on the Upper Reaches of the Yangtze River & Forestry Ecological Engineering in the Upper Reaches of the Yangtze River Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, China.
| | - Jordi Sardans
- CSIC, Global Ecology Unit CREAF-CSIC-UAB, 08913 Bellaterra, Catalonia, Spain; CREAF, 08913 Cerdanyola del Vallès, Catalonia, Spain; Nonlinear Analysis and Applied Mathematics (NAAM)-Research Group, Department of Mathematics, Faculty of Science, King Abdulaziz University, P.O. Box 80257, Jeddah 21589, Saudi Arabia
| | - Josep Peñuelas
- CREAF, 08913 Cerdanyola del Vallès, Catalonia, Spain; Nonlinear Analysis and Applied Mathematics (NAAM)-Research Group, Department of Mathematics, Faculty of Science, King Abdulaziz University, P.O. Box 80257, Jeddah 21589, Saudi Arabia
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10
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Zhan T, Zhao H, Zhang J, Cheng C, Zhang Z. Differential effects of grazing intensity on carbon sequestration in arid versus humid grasslands across China. Sci Total Environ 2023; 881:163221. [PMID: 37019229 DOI: 10.1016/j.scitotenv.2023.163221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 03/23/2023] [Accepted: 03/28/2023] [Indexed: 06/01/2023]
Abstract
Livestock grazing, as a primary utilization practice for grasslands, plays a crucial role in carbon cycling process and its budget. Whether the impacts of different grazing intensities on carbon sequestration vary with precipitation over a broad geographic scales across China's grasslands remains unclear. In the context of striving for carbon neutrality, we carried out a meta-analysis based on 156 peer-reviewed journal articles to synthesize the general impacts of different grazing intensities on carbon sequestration with different precipitations. Our results showed that light, moderate, and heavy grazing dramatically reduced the soil organic carbon stocks by 3.43 %, 13.68 %, and 16.77 % in arid grasslands, respectively (P < 0.05), while light and moderate grazing did not alter soil organic carbon stocks in humid grasslands (P > 0.05). Moreover, the change rates of soil organic carbon stocks were all tightly positively associated with those of soil water content under different grazing intensities (P < 0.05). Further analysis revealed strong positive relationships between mean annual precipitation with the change rates of above- and belowground biomasses, soil microbial biomass carbon, and soil organic carbon stocks under moderate grazing intensity (P < 0.05). These findings imply that carbon sequestration is relatively less tolerant to grazing disturbance in arid grasslands than humid grasslands, which may be primary due to the grazing-intensified water limitation for plant growth and soil microbial activities under low precipitation. Our study is of implication to predict carbon budget of China's grasslands and help adopt sustainable management to strive for carbon neutrality.
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Affiliation(s)
- Tianyu Zhan
- Key Laboratory of National Forestry and Grassland Administration on Grassland Resources and Ecology in the Yellow River Delta, College of Grassland Science, Qingdao Agricultural University, Qingdao 266109, Shandong, China; State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China
| | - Haotian Zhao
- Sichuan Engineering Technology Research Center of Geohazard Prevention, Chengdu 610081, China
| | - Jiaxi Zhang
- College of Tourism and Geographical Science, Leshan Normal University, Leshan 61400, China
| | - Chunyan Cheng
- College of Geography and Remote sensing Sciences, Xinjiang University, Urumqi 830046, China
| | - Zhenchao Zhang
- Key Laboratory of National Forestry and Grassland Administration on Grassland Resources and Ecology in the Yellow River Delta, College of Grassland Science, Qingdao Agricultural University, Qingdao 266109, Shandong, China.
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11
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Guo X, Arshad MU, Zhao Y, Gong Y, Li H. Effects of climate change and grazing intensity on grassland productivity-A case study of Inner Mongolia, China. Heliyon 2023; 9:e17814. [PMID: 37483780 PMCID: PMC10359864 DOI: 10.1016/j.heliyon.2023.e17814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 06/27/2023] [Accepted: 06/28/2023] [Indexed: 07/25/2023] Open
Abstract
In the last 30 years, grassland productivity has declined seriously due to climate variations and unreasonable human activities. Therefore, to analyze the impact of different factors on grassland productivity, we selected three grassland stations of the Typical Steppe from west to east and collected 38 years of data. The Pearson Correlation and Fixed Effect Model were used to analyze the impact of precipitation, temperature, and grazing intensity on grassland productivity. The empirical results show that precipitation positively and significantly affected grassland productivity. The effects of climate change are more significant than human activities, but the impact of temperature is greater than precipitation. The synergy between precipitation and temperature was greater than between precipitation and temperature separately. In addition, the effects of climate change and human activities on grassland productivity have evident regional heterogeneity. The variation trend gradually increases from west to east in factors that affect grassland productivity. Therefore, we suggest some implications for grassland risk management, such as utilizing some financial products for climate risk and focusing on the synergy index to design financial products, such as design weather derivatives. Lastly, we should strengthen the research on the relationship between climate change and grassland productivity to provide a scientific basis for revealing the intrinsic relationship between climate, human activities, and grassland productivity.
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Affiliation(s)
- Xinya Guo
- Shandong University of Technology, School of Economics, Shandong, China
- Inner Mongolia Agricultural University, College of Economics and Management, Inner Mongolia, Hohhot, China
| | | | - Yuanfeng Zhao
- Inner Mongolia Agricultural University, College of Economics and Management, Inner Mongolia, Hohhot, China
| | - Yufei Gong
- Fuzhou University of International Studies and Trade, Fuzhou, China
| | - Hongyu Li
- Laiwu Branch of the People's Bank of China, Shandong, China
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12
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Song L, Gong J, Zhang Z, Zhang W, Zhang S, Dong J, Dong X, Hu Y, Liu Y. Changes in plant phosphorus demand and supply relationships in response to different grazing intensities affect the soil organic carbon stock of a temperate steppe. Sci Total Environ 2023; 876:163225. [PMID: 37011672 DOI: 10.1016/j.scitotenv.2023.163225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 03/23/2023] [Accepted: 03/29/2023] [Indexed: 06/19/2023]
Abstract
Ongoing climate change and long-term overgrazing are the main causes of grassland degradation worldwide. Phosphorus (P) is typically a limiting nutrient in degraded grassland soils, and its dynamics may play a crucial role in the responses of carbon (C) feedback to grazing. Yet how multiple P processes respond to a multi-level of grazing and its impact on soil organic carbon (SOC), which is critical for sustainable grassland development in the face of climate change, remains inadequately understood. Here, we investigated P dynamics at the ecosystem level in a 7-year-long multi-level grazing field experiment and analyzed their relation to SOC stock. The results showed that, due to the greater P demand for compensatory plant growth, grazing by sheep increased the aboveground plants' P supply (by 70 % at most) while decreasing their relative P limitation. The increase in P in aboveground tissue was associated with changes in plant root-shoot P allocation and P resorption, and the mobilization of moderately labile organic P in soil. Affected by the altered P supply under grazing, corresponding changes to root C stock and soil total P were two major factors impacting SOC. Compensatory growth-induced P demand and P supply processes responded differently to grazing intensity, resulting in differential effects on SOC. Unlike the light and heavy grazing levels, which reduced the SOC stock, moderate grazing was capable of maintaining maximal vegetation biomass, total plant biomass P, and SOC stock, mainly by promoting biologically- and geochemically-driven plant-soil P turnover. Our findings have important implications for addressing future soil C losses and mitigating higher atmospheric CO2 threats, as well as maintaining high productivity in temperate grasslands.
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Affiliation(s)
- Liangyuan Song
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China
| | - Jirui Gong
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China.
| | - Zihe Zhang
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China
| | - Weiyuan Zhang
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China
| | - Siqi Zhang
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China
| | - Jiaojiao Dong
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China
| | - Xuede Dong
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China
| | - Yuxia Hu
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China
| | - Yingying Liu
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China.
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13
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Hou L, Xin X, Sun H, Tao Y, Chen J, Yan R, Zhang X, Shen B, Altome AIA, Hamed YMZ, Wang X, Nurlan S, Adilbek N, Balzhan A, Kussainova M, Amarjargal A, Fang W, Pulatov A. Grazing-induced cattle behaviour modulates the secondary production in a Eurasian steppe ecosystem. Sci Total Environ 2023; 889:164191. [PMID: 37201816 DOI: 10.1016/j.scitotenv.2023.164191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 04/18/2023] [Accepted: 05/11/2023] [Indexed: 05/20/2023]
Abstract
Livestock-grassland interactions are among the most important relationships in grazed grassland ecosystems, where herbivores play a crucial role in plant community and ecosystem functions. However, previous studies primarily have focused on the responses of grasslands to grazing, with few focussing on the effects of livestock behaviour that in turn would influence livestock intake and primary and secondary productivity. Through a 2-year grazing intensity experiment with cattle in Eurasian steppe ecosystem, global positioning system (GPS) collars were used to monitor animal movements, where animal locations were recorded at 10-min intervals during the growing season. We used a random forest model and the K-means method to classify animal behaviour and quantified the spatiotemporal movements of the animals. Grazing intensity appeared to be the predominant driver for cattle behaviour. Foraging time, distance travelled, and utilization area ratio (UAR) all increased with grazing intensity. The distance travelled was positively correlated with foraging time, yielding a decreased daily liveweight gain (LWG) except at light grazing. Cattle UAR showed a seasonal pattern and reached the maximum value in August. In addition, the canopy height, above-ground biomass, carbon content, crude protein, and energy content of plants all affected cattle behaviour. Grazing intensity and the resulting change in above-ground biomass and forage quality jointly determined the spatiotemporal characteristics of livestock behaviour. Increased grazing intensity limited forage resources and promoted intraspecific competition of livestock, which induced longer travelling distance and foraging time, and more even spatial distribution when seeking habitat, which ultimately led to a reduction in LWG. In contrast, under light grazing where there were sufficient forage resources, livestock exhibited higher LWG with less foraging time, shorter travelling distance, and more specialized habitat occupation. These findings support the Optimal Foraging Theory and the Ideal Free Distribution model, which may have important implications for grassland ecosystem management and sustainability.
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Affiliation(s)
- Lulu Hou
- National Hulunbuir Grassland Ecosystem Observation and Research Station, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xiaoping Xin
- National Hulunbuir Grassland Ecosystem Observation and Research Station, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China.
| | - Haixia Sun
- Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, China
| | - Yi Tao
- Key Laboratory of Animal Ecology and Conservation Biology, Centre for Computational Biology and Evolution, Chinese Academy of Sciences, Beijing 100101, China
| | - Jiquan Chen
- Department of Geography, Environment, and Spatial Sciences, Michigan State University, East Lansing, MI 48824, United States of America
| | - Ruirui Yan
- National Hulunbuir Grassland Ecosystem Observation and Research Station, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China.
| | - Xiang Zhang
- College of Geographical Sciences, Inner Mongolia Normal University, Hohhot, China
| | - Beibei Shen
- National Hulunbuir Grassland Ecosystem Observation and Research Station, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China
| | | | | | - Xu Wang
- National Hulunbuir Grassland Ecosystem Observation and Research Station, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Serekpaev Nurlan
- S. Seifullin Kazakh Agrotechnical University, Astana, Kazakhstan
| | - Nogayev Adilbek
- LLP "Scientific and Production Center of Grain Farming Named after A.I. Barayev", Kazakhstan
| | - Akhylbekova Balzhan
- LLP "Scientific and Production Center of Grain Farming Named after A.I. Barayev", Kazakhstan
| | - Maira Kussainova
- Sustainable Agriculture Center, Kazakh National Agrarian Research University, Almaty, Kazakhstan
| | | | - Wei Fang
- Department of Biology, Pace University, New York, NY 10038, USA
| | - Alim Pulatov
- EcoGIS Center, National Research University "Tashkent Institute of Irrigation and Agricultural Mechanization Engineers" (NRU-TIIAME), Tashkent 100000, Uzbekistan
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14
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Jin Y, Tian D, Li J, Wu Q, Pan Z, Han M, Wang Y, Zhang J, Han G. Water causes divergent responses of specific carbon sink to long-term grazing in a desert grassland. Sci Total Environ 2023; 873:162166. [PMID: 36801405 DOI: 10.1016/j.scitotenv.2023.162166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 02/06/2023] [Accepted: 02/07/2023] [Indexed: 06/18/2023]
Abstract
Heavy grazing generally reduces grassland biomass, further decreasing its carbon sink. Grassland carbon sink is determined by both plant biomass and carbon sink per unit biomass (specific carbon sink). This specific carbon sink could reflect grassland adaptative response, because plants generally tend to adaptively enhance the functioning of their remaining biomass after grazing (i.e. higher leaf nitrogen content). Though we know well about the regulation of grassland biomass on carbon sink, little attention is paid to the role of specific carbon sink. Thus, we conducted a 14-year grazing experiment in a desert grassland. Ecosystem carbon fluxes, including net ecosystem CO2 exchange (NEE), gross ecosystem productivity (GEP) and ecosystem respiration (ER), were measured frequently during five consecutive growing seasons with contrasting precipitation events. We found that heavy grazing reduced NEE more in drier (-94.0 %) than wetter (-33.9 %) years. However, grazing did not reduce community biomass much more in drier (-70.4 %) than wetter years (-66.0 %). These meant a positive response of specific NEE (NEE per unit biomass) to grazing in wetter years. This positive response of specific NEE was mainly caused by a higher biomass ratio of other species versus perennial grasses with greater leaf nitrogen content and specific leaf area in wetter years. In addition, we also detected a shift of grazing effects on specific NEE from positive in wetter years to negative in drier years. Overall, this study is among the first to reveal the adaptive response of grassland specific carbon sink to experimental grazing in plant trait view. The stimulation response of specific carbon sink can partially compensate for the loss of grassland carbon storage under grazing. These new findings highlight the role of grassland adaptive response in decelerating climate warming.
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Affiliation(s)
- Yuxi Jin
- Key Laboratory of Grassland Resources of the Ministry of Education, Key Laboratory of Forage Cultivation, Processing and High Efficient Utilization of the Ministry of Agriculture and Rural Affairs, Inner Mongolia Key Laboratory of Grassland Management and Utilization, College of Grassland, Resources and Environment, Inner Mongolia Agricultural University, Hohhot 010011, China
| | - Dashuan Tian
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China.
| | - Jiangwen Li
- College of Life Sciences, Yan' an University, Yan' an 716000, China
| | - Qian Wu
- Key Laboratory of Grassland Resources of the Ministry of Education, Key Laboratory of Forage Cultivation, Processing and High Efficient Utilization of the Ministry of Agriculture and Rural Affairs, Inner Mongolia Key Laboratory of Grassland Management and Utilization, College of Grassland, Resources and Environment, Inner Mongolia Agricultural University, Hohhot 010011, China
| | - Zhanlei Pan
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
| | - Mengqi Han
- Key Laboratory of Grassland Resources of the Ministry of Education, Key Laboratory of Forage Cultivation, Processing and High Efficient Utilization of the Ministry of Agriculture and Rural Affairs, Inner Mongolia Key Laboratory of Grassland Management and Utilization, College of Grassland, Resources and Environment, Inner Mongolia Agricultural University, Hohhot 010011, China
| | - Yuehua Wang
- Key Laboratory of Grassland Resources of the Ministry of Education, Key Laboratory of Forage Cultivation, Processing and High Efficient Utilization of the Ministry of Agriculture and Rural Affairs, Inner Mongolia Key Laboratory of Grassland Management and Utilization, College of Grassland, Resources and Environment, Inner Mongolia Agricultural University, Hohhot 010011, China
| | - Jun Zhang
- College of Science, Inner Mongolia Agricultural University, Hohhot 010011, China
| | - Guodong Han
- Key Laboratory of Grassland Resources of the Ministry of Education, Key Laboratory of Forage Cultivation, Processing and High Efficient Utilization of the Ministry of Agriculture and Rural Affairs, Inner Mongolia Key Laboratory of Grassland Management and Utilization, College of Grassland, Resources and Environment, Inner Mongolia Agricultural University, Hohhot 010011, China.
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15
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Shang J, Zhang Y, Peng Y, Huang Y, Zhu L, Wu Z, Wang J, Cui Y. Climate change drives NDVI variations at multiple spatiotemporal levels rather than human disturbance in Northwest China. Environ Sci Pollut Res Int 2022; 29:13782-13796. [PMID: 34599448 DOI: 10.1007/s11356-021-16774-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 09/23/2021] [Indexed: 06/13/2023]
Abstract
Changes in land management and climate alter vegetation dynamics; however, the factors driving vegetation changes remain elusive at multiple spatiotemporal levels. Here, we assess the drivers of changes in greenness from 2000 to 2015 in Northwest China (NW China). We used multiple stepwise linear regression (MSLR), redundancy analysis (RDA), and 12 other models to quantify the impacts of precipitation and temperature metrics, gross domestic product (GDP), population, and grazing intensity on the normalized difference vegetation index (NDVI) at three administrative levels (county, town, and village), four temporal levels (yearly, May, July, and September), two vegetation types (woodland and grassland), and at annual precipitation gradients of <200, 200-400, and >400 mm. The results suggest that NW China underwent vegetation greening from 2000 to 2015. Precipitation and temperature were the most influential factors contributing to the NDVI change. Population was the main determinant of NDVI under the precipitation gradient of <200 mm, and the effect of GDP on NDVI was moderate. On the temporal scale, annual precipitation, precipitation before the previous year, and precipitation in the current year determined the NDVI in May, July, and September, respectively, for both woodland and grassland. At multiple scales, climate change was the primary driver of vegetation change in NW China, rather than human disturbance. These findings expand our understanding on drivers of NDVI at multiple levels over a long period. Measures to manage decreasing vegetation coverage may be more effective and could be implemented sooner based on predicted climate change in drylands worldwide.
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Affiliation(s)
- Jiaxin Shang
- Key Laboratory of Ecology and Environment in Minority Areas (Minzu University of China), National Ethnic Affairs Commission, Beijing, 100081, China
- College of Life & Environmental Sciences, Minzu University of China, Beijing, 100081, China
| | - Yang Zhang
- Key Laboratory of Ecology and Environment in Minority Areas (Minzu University of China), National Ethnic Affairs Commission, Beijing, 100081, China
- College of Life & Environmental Sciences, Minzu University of China, Beijing, 100081, China
| | - Yu Peng
- Key Laboratory of Ecology and Environment in Minority Areas (Minzu University of China), National Ethnic Affairs Commission, Beijing, 100081, China.
- College of Life & Environmental Sciences, Minzu University of China, Beijing, 100081, China.
| | - Yihang Huang
- Key Laboratory of Ecology and Environment in Minority Areas (Minzu University of China), National Ethnic Affairs Commission, Beijing, 100081, China
- College of Life & Environmental Sciences, Minzu University of China, Beijing, 100081, China
| | - Lu Zhu
- Key Laboratory of Ecology and Environment in Minority Areas (Minzu University of China), National Ethnic Affairs Commission, Beijing, 100081, China
- College of Life & Environmental Sciences, Minzu University of China, Beijing, 100081, China
| | - Zhuoyi Wu
- Key Laboratory of Ecology and Environment in Minority Areas (Minzu University of China), National Ethnic Affairs Commission, Beijing, 100081, China
- College of Life & Environmental Sciences, Minzu University of China, Beijing, 100081, China
| | - Jing Wang
- Key Laboratory of Ecology and Environment in Minority Areas (Minzu University of China), National Ethnic Affairs Commission, Beijing, 100081, China
- College of Life & Environmental Sciences, Minzu University of China, Beijing, 100081, China
| | - Yixin Cui
- Key Laboratory of Ecology and Environment in Minority Areas (Minzu University of China), National Ethnic Affairs Commission, Beijing, 100081, China
- College of Life & Environmental Sciences, Minzu University of China, Beijing, 100081, China
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16
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Wang J, Li W, Cao W, Wang S. Effects of different intensities of long-term grazing on plant diversity, biomass and carbon stock in alpine shrubland on the Qinghai-Tibetan Plateau. PeerJ 2022; 10:e12771. [PMID: 35070507 PMCID: PMC8760858 DOI: 10.7717/peerj.12771] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 12/19/2021] [Indexed: 01/07/2023] Open
Abstract
Grazing is the main grassland management strategy applied in alpine shrubland ecosystems on the Qinghai-Tibetan Plateau. However, how different intensities of long-term grazing affect plant diversity, biomass accumulation and carbon (C) stock in these ecosystems is poorly understood. In this study, alpine shrubland with different long-term (more than 30 years) grazing intensities (excluded from grazing for 5 years (EX), light grazing (LG), moderate grazing (MG) and heavy grazing (HG)) on the Qinghai-Tibetan Plateau were selected to study changes in plant diversity, aboveground biomass and C accumulation, as well as distribution of C stock among biomass components and soil depths. A structural equation model was used to illustrate the impact of grazing on the soil carbon stock (SOC). The results showed that the Shannon-Wiener diversity index and richness index of herbaceous plants, shrubs, and communities first significantly increased and then decreased with increasing grazing intensity, reaching maxima at the LG site. The aboveground and belowground and litter biomass of understory herbaceous plants, shrubs and communities decreased with increasing grazing intensity, reaching maxima at the EX site. The aboveground and belowground biomass C storage decreased with increasing grazing intensity, reaching maxima at the EX site. The SOC stock and total ecosystem C stock decreased with increasing grazing intensity, reaching maxima at the EX and LG sites. A structural equation model showed that grazing-induced changes in the belowground biomass of understory herbaceous plants greatly contributed to the SOC stock decrease. Thus, considering the utilization and renewal of grassland resources, as well as local economic benefits and ecological effects, LG may be a more rational grazing intensity for species diversity conservation and ecosystem C sequestration in alpine shrubland. Our results provide new insights for incorporating grazing intensity into shrub ecosystem C stock and optimizing grazing management and grassland ecosystem C management.
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Affiliation(s)
- Jinlan Wang
- Gansu Agricultural University, Grassland Science College, Lanzhou, Gansu, China
| | - Wen Li
- Qinghai University, Qinghai Academy of Animal Science and Veterinary Medicine, Xining, Qinghai, China
| | - Wenxia Cao
- Gansu Agricultural University, Grassland Science College, Lanzhou, Gansu, China
| | - Shilin Wang
- Gansu Agricultural University, Grassland Science College, Lanzhou, Gansu, China
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17
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Fenetahun Y, You Y, Fentahun T, Xinwen X, Yong-Dong W. Effects of grazing intensity on forage nutritive value of dominant grass species in Borana rangelands of Southern Ethiopia. PeerJ 2021; 9:e12204. [PMID: 34721964 PMCID: PMC8542370 DOI: 10.7717/peerj.12204] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 09/03/2021] [Indexed: 12/02/2022] Open
Abstract
Background Forage nutritive value analysis is an essential indicator of rangeland status regarding degradation and livestock nutrient demand. Thus, it is used to maintain healthy and sustainable rangelands that can provide the livestock with sufficient quantity and quality of forage. This study is conducted with the aim of investigating the effects of grazing intensity combined with seasonal variation on the nutritive values of dominant grass species in the Teltele rangeland. Methods The studied area is classified into no-grazed, moderately grazed, and overgrazed plots based on the estimated potential carrying capacity. Sampling data is collected during both rainy and dry seasons. The collected forage samples are analyzed for concentrations of crude protein (CP), acid detergent organic fiber (ADF), neutral detergent fiber (NDF), acid detergent lignin (ADL), ash, dry matter digestibility (DMD), potential dry matter intake (DMI), and relative feed/forage value (RFV). Results The results show significant (P < 0.05) effects of both grazing intensity and season to grazing intensity interactions on all forage nutrient content concentrations across all grass species both within and between treatments. The recorded CP concentrations of all grass species are high in the overgrazed site and low at the no-grazed site, while the fiber concentration is high in NG and low in OG. RFV data also varies greatly, with high value recorded in OG in the rainy season and low value found in NG mainly during the dry season. As a result, it is recommended that moderate grazing should be practiced on the study site to maintain the quality and quantity of forage and to manage it in a sustainable manner.
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Affiliation(s)
- Yeneayehu Fenetahun
- University of China Academy of Sciences, Beijing, China.,National Engineering Technology Research Center for Desert-Oasis Ecological Construction, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China
| | - Yuan You
- National Engineering Technology Research Center for Desert-Oasis Ecological Construction, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China
| | - Tihunie Fentahun
- College of Natural and Computational Sciences, Mekdela Amba University, Tulu Awuliya, Ethiopia
| | - Xu Xinwen
- National Engineering Technology Research Center for Desert-Oasis Ecological Construction, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China
| | - Wang Yong-Dong
- National Engineering Technology Research Center for Desert-Oasis Ecological Construction, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China
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Bjerke JW, Tombre IM, Hanssen M, Olsen AKB. Springtime grazing by Arctic-breeding geese reduces first- and second-harvest yields on sub-Arctic agricultural grasslands. Sci Total Environ 2021; 793:148619. [PMID: 34182443 DOI: 10.1016/j.scitotenv.2021.148619] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 06/11/2021] [Accepted: 06/19/2021] [Indexed: 06/13/2023]
Abstract
Large population increases of Arctic-breeding waterfowls over recent decades have intensified the conflict with agricultural interests in both Eurasia and North America. In the spring-staging region Vesterålen in sub-Arctic Norway, sheep, dairy and meat farmers have reported reduced agricultural grassland yields due to pink-footed geese Anser brachyrhynchus and barnacle geese Branta leucopsis that rest and forage in the region for 3-4 weeks in spring on their way to their breeding grounds on Svalbard. Here, we report from an experimental exclosure design where goose access to plots at three grassland fields in Vesterålen was prevented. The experiment was conducted over 3 years between 2012 and 2014. Goose abundance varied greatly between fields and years as a function of variable spring weather and forage quantity, facilitating evaluation of longer-term impacts under contrasting grazing intensities. First and second harvest yields across fields and years were 20% and 19% higher in exclosures than in plots open for grazing, while total yields (sum of first and second harvests) were on average 27% higher. Within-year effects on harvest yields varied substantially, primarily due to highly contrasting sward development during the spring-staging periods. Cool weather (2012) led to slow sward development and little or no effects on harvest yields, warmer weather (2013) resulted in generally large effects, while variable weather (2014) led to treatment effects varying across fields, with one field experiencing 61% higher yields in exclosures while there were no significant impacts on first-harvest yields at the two other fields. Goose grazing did not increase dry weight-based proportions of weeds. Overall, the farmers' reports on yield-loss due to goose grazing were confirmed, although impacts varied substantially between years. A novel finding is that second-harvest yields were also reduced. For the most affected farmers, it is unlikely that the current subsidy scheme is sufficient to cover all the their losses.
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Affiliation(s)
- Jarle W Bjerke
- Norwegian Institute for Nature Research (NINA), Fram - High North research Centre for Climate and the Environment, P.O. Box 6606, Langnes N-9296, Norway.
| | - Ingunn M Tombre
- Norwegian Institute for Nature Research (NINA), Fram - High North research Centre for Climate and the Environment, P.O. Box 6606, Langnes N-9296, Norway
| | - Marvell Hanssen
- Norsk landbruksrådgivning, Kleiva, N-8404 Sortland, Norway; Lilandvegen 42, N-8407 Sortland, Norway
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Dastgheyb Shirazi SS, Ahmadi A, Abdi N, Toranj Zar H, Khaleghi MR. Moderate grazing is the best measure to achieve the optimal conservation and soil resource utilization (case study: Bozdaghin rangelands, North Khorasan, Iran). Environ Monit Assess 2021; 193:549. [PMID: 34345952 DOI: 10.1007/s10661-021-09334-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 07/22/2021] [Indexed: 06/13/2023]
Abstract
The study of the variability of physical and chemical factors of soil due to different intensities of livestock grazing can help in the management and maintenance of soil and vegetation. Accordingly, the effect of livestock grazing intensities on soil properties and vegetation in Bozdaghin rangelands of North Khorasan province was investigated. To investigate the effect of different livestock grazing intensities, Three 5-hectare plots in the study area were determined under different treatments (ungrazed (UG), moderate grazing (MG), and heavy grazing (HG)), and the effect of three grazing intensities on vegetation and soil physicochemical and erodibility properties (SPEP) was evaluated. The soil sampling process was performed at depths of 0-15, 15-30 cm and SPEP including soil saturation moisture (SSM), soil texture (percentage of clay, sand, and silt), absorbable potassium (K), electrical conductivity (EC), soil organic matter (SOM), absorbable phosphorus (P), acidity (pH), and bulk density were evaluated, and Soil Erodibility Index (SEI) was calculated by implementing the modified clay ratio relation. To assess the impact of various grazing intensities on all measured characteristics, multivariate analysis of variance (MANOVA) and Duncan tests were utilized to compare the means and their grouping. The results showed that HG compared to MG causes worrying consequences in the first soil depth. Also with increasing grazing intensity, plant production percentage (P < 0.05) and vegetation density (P < 0.01) decreased, and the amount of bare soil (P < 0.01) increased. Also, with increasing grazing intensity, the amount of pH, EC, clay, saturated moisture, and N decreased (P < 0.01), but the amount of silt, sand, K, P, calcium (Ca), lime, and SOM increased (P < 0.01). UG improves soil quality, MG intensity causes optimal conservation and utilization of soil resources, and HG intensity causes severe changes in rangeland soil properties. In areas with MG intensity, due to the increase of the percentage of vegetation (an increase of SOM and prevents the direct impact of raindrops on the soil aggregates) and as a result improvement of soil structure and texture, an increase of water infiltration, and decrease of runoff, and the rate of soil erodibility and water erosion, the rangeland soil decreases and results in sustainable production. This results in optimal conservation and utilization of soil resources. So to sustainably exploit and balance the conservation of biodiversity, livestock production, and soil carbon and nitrogen management, MG is recommended.
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Affiliation(s)
| | - A Ahmadi
- Department of Natural Resources, Arak Branch, Islamic Azad University, Arak, Iran.
| | - N Abdi
- Department of Natural Resources, Arak Branch, Islamic Azad University, Arak, Iran
| | - H Toranj Zar
- Department of Natural Resources, Arak Branch, Islamic Azad University, Arak, Iran
| | - M R Khaleghi
- Department of Natural Resources, Torbat-E-Jam Branch, Islamic Azad University, Torbat-e-Jam, Iran
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20
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Cezimbra IM, de Albuquerque Nunes PA, de Souza Filho W, Tischler MR, Genro TCM, Bayer C, Savian JV, Bonnet OJF, Soussana JF, de Faccio Carvalho PC. Potential of grazing management to improve beef cattle production and mitigate methane emissions in native grasslands of the Pampa biome. Sci Total Environ 2021; 780:146582. [PMID: 34030331 DOI: 10.1016/j.scitotenv.2021.146582] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 03/15/2021] [Accepted: 03/15/2021] [Indexed: 06/12/2023]
Abstract
We tested the hypothesis that improving sward structure through adjustments in forage allowance results in greater forage intake and live weight (LW) gains by beef cattle and lower CH4 emissions per unit LW gain and unit area in a native grassland ecosystem of the Pampa biome. The experiment was carried out during 2012 and 2013 in southern Brazil. The experimental design was a randomized complete block with two replicates. Treatments consisted of five contrasting forage allowances of a native grassland managed under continuous stocking: 4, 8, 8-12, 12, and 16 kg of dry matter (DM) 100 kg LW-1 day-1 (or % LW). The 8-12% LW treatment had a variable forage allowance of 8% LW in spring and 12% LW in summer, autumn, and winter. Forage allowance was controlled by changes in stocking rate (kg LW ha-1). Average daily gain (kg LW day-1) was high for forage allowances of 12 and 16% LW but decreased at 8%, reaching the lowest value at 4% LW treatment (p < 0.001). Live weight gain ha-1 year-1 was the greatest at forage allowance of 8-12% LW (p < 0.001). Forage DM intake peaked at a forage allowance of 12% LW (p = 0.005). Individual CH4 emissions remained constant around 150 g day-1 for the two highest forage allowances and decreased to 118 and 107 g day-1 under forage allowances of 8 and 4% LW, respectively (p = 0.002). Emissions per unit LW gain and unit area were driven by animal productivity changes and decreased with increasing forage allowance (p = 0.001 and p = 0.040, respectively). We propose that the combination of 8% LW forage allowance during spring and 12% LW during the rest of the year should be targeted to best balance animal production and environmental impact in the Pampa biome.
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Affiliation(s)
- Ian Machado Cezimbra
- Department of Forage Plants and Agrometeorology, Federal University of Rio Grande do Sul (UFRGS), 7712 Bento Gonçalves Ave., Porto Alegre, RS 91540-000, Brazil
| | - Pedro Arthur de Albuquerque Nunes
- Department of Forage Plants and Agrometeorology, Federal University of Rio Grande do Sul (UFRGS), 7712 Bento Gonçalves Ave., Porto Alegre, RS 91540-000, Brazil
| | - William de Souza Filho
- Department of Forage Plants and Agrometeorology, Federal University of Rio Grande do Sul (UFRGS), 7712 Bento Gonçalves Ave., Porto Alegre, RS 91540-000, Brazil
| | - Marcelo Ritzel Tischler
- Department of Forage Plants and Agrometeorology, Federal University of Rio Grande do Sul (UFRGS), 7712 Bento Gonçalves Ave., Porto Alegre, RS 91540-000, Brazil
| | | | - Cimélio Bayer
- Department of Soil Science, Federal University of Rio Grande do Sul, 7712 Bento Gonçalves Ave., Porto Alegre, RS 91540-000, Brazil
| | - Jean Víctor Savian
- Instituto Nacional de Investigación Agropecuaria (INIA), Programa Pasturas y Forrajes, Estación Experimental INIA Treinta y Tres, Ruta 8, Km 281, Treinta y Tres, Uruguay
| | - Olivier Jean François Bonnet
- Department of Forage Plants and Agrometeorology, Federal University of Rio Grande do Sul (UFRGS), 7712 Bento Gonçalves Ave., Porto Alegre, RS 91540-000, Brazil
| | - Jean-François Soussana
- Unité Mixte de Recherche sur l'Écosystème Prairial (UREP), Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE), Clermont-Ferrand, France
| | - Paulo César de Faccio Carvalho
- Department of Forage Plants and Agrometeorology, Federal University of Rio Grande do Sul (UFRGS), 7712 Bento Gonçalves Ave., Porto Alegre, RS 91540-000, Brazil.
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21
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Zhang R, Wang Z, Niu S, Tian D, Wu Q, Gao X, Schellenberg MP, Han G. Diversity of plant and soil microbes mediates the response of ecosystem multifunctionality to grazing disturbance. Sci Total Environ 2021; 776:145730. [PMID: 33639460 DOI: 10.1016/j.scitotenv.2021.145730] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 01/04/2021] [Accepted: 02/04/2021] [Indexed: 05/27/2023]
Abstract
Biodiversity drives ecosystem functioning across grassland ecosystems. However, few studies have examined how grazing intensity affects ecosystem multifunctionality (EMF) via its effects on plant diversity and soil microbial diversity in dry grasslands. We conducted a 12-year experiment manipulating sheep grazing intensity in a desert steppe of northern China. Through measuring plant species diversity, soil microbial diversity (bacteria diversity) and multiple ecosystem functions (i.e., aboveground net primary productivity, belowground biomass of plant community, temporal stability of ANPP, soil organic matter, moisture, available nitrogen and phosphorus, ecosystem respiration and gross ecosystem productivity), we aimed to understand how grazing intensity affected EMF via changing the diversity of plants and microbes. Our results showed that increasing grazing intensity significantly reduced EMF and most individual ecosystem functions, as well as the diversity of plants and microbes, while EMF and most individual functions were positively related to plant diversity and soil microbial diversity under all grazing intensities. In particular, soil microbial diversity in shallow soil layers (0-5 cm depth) had stronger positive correlations with plant diversity and EMF than in deeper soil layers. Furthermore, structural equation modeling (SEM) showed that grazing reduced EMF mainly via reducing plant diversity, rather than by reducing soil microbial diversity. Thus, plant diversity played a more important role in mediating the response of EMF to grazing disturbance. This study highlights the critical role of above- and belowground diversity in mediating the response of EMF to grazing intensity, which has important implications for biodiversity conservation and sustainability in arid grasslands.
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Affiliation(s)
- Ruiyang Zhang
- Key Laboratory of Grassland Resources of the Ministry of Education, Key Laboratory of Forage Cultivation, Processing and High Efficient Utilization of the Ministry of Agriculture and Rural Affairs, Inner Mongolia Key Laboratory of Grassland Management and Utilization, College of Grassland, Resources and Environment, Inner Mongolia Agricultural University, No. 29 Erdos St., Hohhot, Inner Mongolia 010011, China; Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Zhongwu Wang
- Key Laboratory of Grassland Resources of the Ministry of Education, Key Laboratory of Forage Cultivation, Processing and High Efficient Utilization of the Ministry of Agriculture and Rural Affairs, Inner Mongolia Key Laboratory of Grassland Management and Utilization, College of Grassland, Resources and Environment, Inner Mongolia Agricultural University, No. 29 Erdos St., Hohhot, Inner Mongolia 010011, China.
| | - Shuli Niu
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
| | - Dashuan Tian
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Qian Wu
- Key Laboratory of Grassland Resources of the Ministry of Education, Key Laboratory of Forage Cultivation, Processing and High Efficient Utilization of the Ministry of Agriculture and Rural Affairs, Inner Mongolia Key Laboratory of Grassland Management and Utilization, College of Grassland, Resources and Environment, Inner Mongolia Agricultural University, No. 29 Erdos St., Hohhot, Inner Mongolia 010011, China
| | - Xuefeng Gao
- College of Life Sciences and Technology, Inner Mongolia Normal University, No. 81 Zhaowuda Road, Saihan District, Hohhot, Inner Mongolia 010020, China
| | - Michael P Schellenberg
- Swift Current Research and Development Centre, Agriculture and Agri-Food Canada, 1 Airport Rd., Box 1030, Swift Current, Saskatchewan S9H 3X2, Canada
| | - Guodong Han
- Key Laboratory of Grassland Resources of the Ministry of Education, Key Laboratory of Forage Cultivation, Processing and High Efficient Utilization of the Ministry of Agriculture and Rural Affairs, Inner Mongolia Key Laboratory of Grassland Management and Utilization, College of Grassland, Resources and Environment, Inner Mongolia Agricultural University, No. 29 Erdos St., Hohhot, Inner Mongolia 010011, China
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22
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Su L, Tang J, Qiu H. Intended and unintended environmental consequences of grassland rental in pastoral China. J Environ Manage 2021; 285:112126. [PMID: 33582475 DOI: 10.1016/j.jenvman.2021.112126] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 02/03/2021] [Accepted: 02/03/2021] [Indexed: 06/12/2023]
Abstract
Among herders, market-oriented grassland rental has been prevalent in China following the implementation of the Household Contracted Responsibility System, which allocated formerly collectively-owned use rights to individual herders. However, empirical evidence on the effect of grassland rental on herder households' overgrazing behaviour is scant, despite the fact that it is one of the main determinants of the severe grassland degradation in China. This study thus investigates the effects of grassland rental on both household- and plot-level grazing intensity and overgrazing based on a survey of 876 plots and 516 households in the Inner Mongolia, Qinghai, and Gansu provinces in China. An instrumental variable approach is utilised to correct the endogeneity bias of herders' decision to rent in grassland. The household-level empirical results show that each 1000-mu increment of rent-in grassland leads to an intended 42% decrease in the overall grazing intensity and a 61% decrease in the overgrazing index. However, a plot-level analysis pooling both rent-in and self-owned grassland plots reveals the unintended consequence that herders are over-exploiting rent-in grassland plots; as a result, the grazing intensity on rent-in grassland is 2.03 times that on owned grassland. Therefore, grassland rental should be encouraged, but the monitoring system should pay more attention to the overgrazing of rental grassland.
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Affiliation(s)
- Liufang Su
- School of Agricultural Economics and Rural Development, Renmin University of China, Beijing, China
| | - Jianjun Tang
- School of Agricultural Economics and Rural Development, Renmin University of China, Beijing, China
| | - Huanguang Qiu
- School of Agricultural Economics and Rural Development, Renmin University of China, Beijing, China.
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23
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Liu M, Gong J, Yang B, Ding Y, Zhang Z, Wang B, Zhu C, Hou X. Differences in the photosynthetic and physiological responses of Leymus chinensis to different levels of grazing intensity. BMC Plant Biol 2019; 19:558. [PMID: 31842774 PMCID: PMC6916219 DOI: 10.1186/s12870-019-2184-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 12/03/2019] [Indexed: 05/14/2023]
Abstract
BACKGROUND Grazing is an important land use in northern China. In general, different grazing intensities had a different impact on the morphological and physiological traits of plants, and especially their photosynthetic capacity. We investigated the responses of Leymus chinensis to light, medium, and heavy grazing intensities in comparison with a grazing exclusion control. RESULTS With light grazing, L. chinensis showed decreased photosynthetic capacity. The low chlorophyll and carotenoid contents constrained light energy transformation and dissipation, and Rubisco activity was also low, restricting the carboxylation efficiency. In addition, the damaged photosynthetic apparatus accumulated reactive oxygen species (ROS). With medium grazing, more energy was used for thermal dissipation, with high carotene content and high non-photochemical quenching, whereas photosynthetic electron transport was lowest. Significantly decreased photosynthesis decreased leaf C contents. Plants decreased the risk caused by ROS through increased energy dissipation. With high grazing intensity, plants changed their strategy to improve survival through photosynthetic compensation. More energy was allocated to photosynthetic electron transport. Though heavy grazing damaged the chloroplast ultrastructure, adjustment of internal mechanisms increased compensatory photosynthesis, and an increased tiller number facilitated regrowth after grazing. CONCLUSIONS Overall, the plants adopted different strategies by adjusting their metabolism and growth in response to their changing environment.
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Affiliation(s)
- Min Liu
- Beijing Key Laboratory of Traditional Chinese Medicine Protection and Utilization, Key Laboratory of Surface Processes and Resource Ecology, College of Resources Science and Technology, Faculty of Geographical Science, Beijing Normal University, No. 19 Xinjiekouwai Street, Beijing, 100875 China
- Key Laboratory of Tourism and Resources, Environment in Taishan University, Taian, 271021 China
| | - Jirui Gong
- Beijing Key Laboratory of Traditional Chinese Medicine Protection and Utilization, Key Laboratory of Surface Processes and Resource Ecology, College of Resources Science and Technology, Faculty of Geographical Science, Beijing Normal University, No. 19 Xinjiekouwai Street, Beijing, 100875 China
| | - Bo Yang
- Beijing Key Laboratory of Traditional Chinese Medicine Protection and Utilization, Key Laboratory of Surface Processes and Resource Ecology, College of Resources Science and Technology, Faculty of Geographical Science, Beijing Normal University, No. 19 Xinjiekouwai Street, Beijing, 100875 China
| | - Yong Ding
- Grassland Research Institute of Chinese Academic of Agricultural Science, Hohhot, 010021 Inner Mongolia China
| | - Zihe Zhang
- Beijing Key Laboratory of Traditional Chinese Medicine Protection and Utilization, Key Laboratory of Surface Processes and Resource Ecology, College of Resources Science and Technology, Faculty of Geographical Science, Beijing Normal University, No. 19 Xinjiekouwai Street, Beijing, 100875 China
| | - Biao Wang
- Beijing Key Laboratory of Traditional Chinese Medicine Protection and Utilization, Key Laboratory of Surface Processes and Resource Ecology, College of Resources Science and Technology, Faculty of Geographical Science, Beijing Normal University, No. 19 Xinjiekouwai Street, Beijing, 100875 China
| | - Chenchen Zhu
- Beijing Key Laboratory of Traditional Chinese Medicine Protection and Utilization, Key Laboratory of Surface Processes and Resource Ecology, College of Resources Science and Technology, Faculty of Geographical Science, Beijing Normal University, No. 19 Xinjiekouwai Street, Beijing, 100875 China
| | - Xiangyang Hou
- Grassland Research Institute of Chinese Academic of Agricultural Science, Hohhot, 010021 Inner Mongolia China
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24
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Li G, Jiang C, Cheng T, Bai J. Grazing alters the phenology of alpine steppe by changing the surface physical environment on the northeast Qinghai-Tibet Plateau, China. J Environ Manage 2019; 248:109257. [PMID: 31344560 DOI: 10.1016/j.jenvman.2019.07.028] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 07/03/2019] [Accepted: 07/08/2019] [Indexed: 06/10/2023]
Abstract
The response of vegetation phenology to environmental changes is very complex. We used time-lapse digital cameras to monitor the phenology of an alpine steppe in four winter pastures with different grazing intensities during 2015-2017. The results showed that the beginning of the growing season (BGS) and the growing season length (GSL) of the alpine steppe separately presented advances or prolonged trends with the increase in grazing intensity. There was no regularity in the end of the growing season (EGS) under the change in grazing intensity gradient, but the EGS of the no grazing (NG) plot occurred 24 days ahead of the other plots disturbed by grazing. Different winter grazing intensities obviously had different influences on the surface litter, soil temperature (ST), and soil moisture (SM) during spring but not during autumn. The ST under different grazing intensities played a decisive role in controlling the BGS of alpine steppe, followed by surface litter and SM. The EGS showed a significant correlation with the surface litter in autumn but did not show correlations with ST and SM. These results could further help us understand the phenological mechanisms of the soil surface and guide the scientific management of grazing to adapt to climate change.
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Affiliation(s)
- Guangyong Li
- Institute of Agricultural Sci-tech Information, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, China; National Geomatics Center of China, Beijing 100830, China.
| | - Cuihong Jiang
- Institute of Agricultural Sci-tech Information, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, China
| | - Tao Cheng
- National Geomatics Center of China, Beijing 100830, China
| | - Ju Bai
- National Geomatics Center of China, Beijing 100830, China
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Fan F, Liang C, Tang Y, Harker-Schuch I, Porter JR. Effects and relationships of grazing intensity on multiple ecosystem services in the Inner Mongolian steppe. Sci Total Environ 2019; 675:642-650. [PMID: 31035202 DOI: 10.1016/j.scitotenv.2019.04.279] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 04/18/2019] [Accepted: 04/18/2019] [Indexed: 06/09/2023]
Abstract
Grassland ecosystems are one of the most important terrestrial ecosystems in the world, producing essential both goods and ecosystem services (ES) for human beings. The Inner Mongolian steppe is a major grassland ecosystem in Northern China, covering 13.5% of the northern Chinese grassland area, and playing important ecological roles for the adjacent region of the capital Beijing-Tianjin-Hebei. Quantification of grassland ES under the different utilization patterns is vital for the maintenance of multiple ES and mitigation against ES loss in this region. We made a manipulative experiment with four grazing intensities (grazing exclusion, GE; light grazing intensity, LG; medium grazing intensity, MG; heavy grazing intensity, HG). We then quantified the intensities of eight different grassland ES (1. herbage intake, HT; 2. biodiversity conservation, BI; 3. soil nutrient retention, SN; 4 soil carbon stocks SC; 5. soil erosion prevention, SEP; 6. soil water storage, SWC; 7. potential nutrient recycling, PNC; 8. carbon sequestration from atmosphere. CS) and total ES via a series of field measurements. Pearson coefficients and trade-offs index were used to access the above ES relationships and degree of trade-offs between ES. Grazing intensities significantly (p < 0.05) affected the grassland intensities of 'regulating', 'culture' and 'provisioning' services, but the 'supporting' services. We found three types of relationships (trade-offs, synergy or neutral) have been found in this study. Trade-offs occurred between 'provisioning' and 'regulating' services. Although GE management presented significantly higher intensity of total ES (0.64) than LG (0.52), LG management significantly weakened the trade-offs between 'provisioning' and 'regulating' services (Trade-offs index 0.22) in comparison with GE (Trade-offs index 11.02). Our study suggests, therefore, that LG is the most suitable grassland utilization practice in the Inner Mongolian steppe.
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Affiliation(s)
- Fan Fan
- College of Resource & Environmental Sciences; National Academy of Agriculture Green Development, China Agricultural University, Beijing 100193, China; Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolia Plateau & Inner Mongolia Key Laboratory of Grassland Ecology, School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China.
| | - Cunzhu Liang
- Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolia Plateau & Inner Mongolia Key Laboratory of Grassland Ecology, School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China.
| | - Yongkang Tang
- Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolia Plateau & Inner Mongolia Key Laboratory of Grassland Ecology, School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China; Alxa League Meteorological Bureau, Alxa 750300, China
| | - Inez Harker-Schuch
- Fenner School of Environment and Society, College of Science, Australian National University, Canberra, 2601, Australia
| | - John R Porter
- System Montpellier SupAgro, INRA, CIHEAM-IAMM, CIRAD, University of Montpellier, Montpellier 34000, France; Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Frederiskberg 1870, Denmark
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26
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Li S, He F, Zhang X, Zhou T. Evaluation of global historical land use scenarios based on regional datasets on the Qinghai-Tibet Area. Sci Total Environ 2019; 657:1615-1628. [PMID: 30677926 DOI: 10.1016/j.scitotenv.2018.12.136] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 11/08/2018] [Accepted: 12/09/2018] [Indexed: 06/09/2023]
Abstract
Global historical land use scenarios are widely used to model human-induced climate change from the regional to global scales. It is necessary to conduct regional scale assessments of these global scenarios, identifying their uncertainties and pointing out directions for improvement. Based on the regional reconstruction Li-dataset, remotely sensed dataset, and grazing intensity dataset, the uncertainties of land use area and geographical distribution in HYDE3.1, HYDE3.2, and SAGE (a global land dataset from the Center for Sustainability and the Global Environment) scenarios for the Qinghai-Tibet Area (QTA) are evaluated. The comparisons show that the cropland areas on the QTA in HYDE3.2 for 1900-2000 are close to those of the Li-dataset, whereas HYDE3.1 underestimated and SAGE overestimated the cropland areas significantly. Spatially, HYDE3.1, HYDE3.2, and SAGE have large uncertainties, which cannot reflect the distribution of cropland on the QTA and its changes for 1900-2000 well, and too much cropland is allocated to southeastern Tibet. HYDE3.1 and HYDE3.2 overestimated the pasture area and its distribution on the QTA significantly. The distribution of pasture in SAGE showed overall an agreement with the spatial pattern for grazing intensity, but changes in grazing intensity for 2000-2010 was not reflected in SAGE. The FAO pasture definition and estimates and the method of using population as a proxy for pasture area are not appropriate for the QTA. Methodology which uses the pasture inventory data to calibrate satellite-based grassland maps to obtain the current pasture maps may also not be appropriate because of the lacking differentiation between natural and anthropogenic grasslands in remotely sensed data. More regional level land use estimates with concise definitions, define the land use more clearly, and stratification reconstruction based on differences in agro-climatic conditions and resource endowments may be used to improve global maps.
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Affiliation(s)
- Shicheng Li
- Department of Land Resource Management, School of Public Administration, China University of Geosciences, Wuhan 430074, China; Shandong Provincial Key Laboratory of Depositional Mineralization & Sedimentary Mineral, Shandong University of Science and Technology, Qingdao 266590, China; Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Fanneng He
- Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
| | - Xuezhen Zhang
- Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Tianyu Zhou
- School of Earth Sciences, China University of Geosciences, Wuhan 430074, China
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Tang S, Ma L, Wei X, Tian D, Wang B, Li Z, Zhang Y, Shao X. Methane emissions in grazing systems in grassland regions of China: A synthesis. Sci Total Environ 2019; 654:662-670. [PMID: 30448656 DOI: 10.1016/j.scitotenv.2018.11.102] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 11/01/2018] [Accepted: 11/07/2018] [Indexed: 06/09/2023]
Abstract
The effects of grazing on methane (CH4) budgets are important for understanding the balance of greenhouse gas emissions and removals in grassland ecosystems. However, the CH4 budgets of grazing systems, that is simultaneously considering CH4 uptake by grassland soils and emissions from ruminant enteric fermentation, livestock folds and animal feces, are poorly investigated, particularly for Chinese grasslands, and thus, remained unclear currently. Here, a synthesis of 43 individual studies was carried out to assess the grazing season/annual CH4 budgets and their responses to grazing in grassland ecosystems of China. The results showed that heavy grazing (HG) significantly decreased, while light grazing (LG) and moderate grazing (MG) had no significant effects soil CH4 uptake, as compared to un-grazing sites. Grazing has shifted Chinese grasslands from a sink to source for atmospheric CH4, and the grazing season/annual CH4 budgets increased with increasing grazing intensity, while the offset of CH4 uptake by grassland soils to total CH4 emissions from sheep, sheepfolds and feces were exponentially decreased with increasing grazing intensity. Moreover, the herbage biomass (HBM), organic matter intake (OMI) and live weight gain (LWG) were decreased while CH4 emission intensities (i.e., CH4 emission per HBM, OMI, and LWG) were linearly increased with increasing grazing intensity. Our results demonstrate that mediating grazing intensity, e.g., from HG to LG, could yield the optimal balance between maintaining productive grasslands and meanwhile mitigating CH4 emissions. This study could help for building strategies with implications for grassland management in China with similar CH4 emission problems.
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Affiliation(s)
- Shiming Tang
- Grassland Department of Animal Science and Technology College, China Agricultural University, No. 2 Yuanmingyuan West Road, Haidian District, Beijing 100193, China; Department of Ecology, School of Ecology and Environment, Inner Mongolia University, No. 235 West College Road, 010021, Hohhot, China
| | - Lei Ma
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry (LAPC), Institute of Atmospheric Physics, Chinese Academy of Sciences (IAP-CAS), Beijing 100029, China
| | - Xiaoting Wei
- Grassland Department of Animal Science and Technology College, China Agricultural University, No. 2 Yuanmingyuan West Road, Haidian District, Beijing 100193, China
| | - Dashuan Tian
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China
| | - Bojie Wang
- Department of Ecology, School of Ecology and Environment, Inner Mongolia University, No. 235 West College Road, 010021, Hohhot, China
| | - Zhaolei Li
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China
| | - Yujuan Zhang
- Institute of Grassland Research, Chinese Academy of Agricultural Sciences, Key Laboratory of Grassland Ecology and Restoration, Ministry of Agriculture, Hohhot 010010, China
| | - Xinqing Shao
- Grassland Department of Animal Science and Technology College, China Agricultural University, No. 2 Yuanmingyuan West Road, Haidian District, Beijing 100193, China.
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Shrestha NK, Thomas BW, Du X, Hao X, Wang J. Modeling nitrous oxide emissions from rough fescue grassland soils subjected to long-term grazing of different intensities using the Soil and Water Assessment Tool (SWAT). Environ Sci Pollut Res Int 2018; 25:27362-27377. [PMID: 30032376 DOI: 10.1007/s11356-018-2719-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2018] [Accepted: 07/04/2018] [Indexed: 06/08/2023]
Abstract
Given the rising nitrous oxide (N2O) concentration in the atmosphere, it has become increasingly important to identify hot spots and hot moments of N2O emissions. With field measurements often failing to capture the spatiotemporal dynamics of N2O emissions, estimating them with modeling tools has become an attractive alternative. Therefore, we incorporated several semi-empirical equations to estimate N2O emissions with the Soil and Water Assessment Tool from nitrification and denitrification processes in soil. We then used the model to simulate soil moisture and the N2O flux from grassland soils subjected to long-term grazing (> 60 years) at different intensities in Alberta, Canada. Sensitivity analysis showed that parameters controlling the N2O flux from nitrification were most sensitive. On average, the accuracy of N2O emission simulations were found to be satisfactory, as indicated by the selected goodness-of-fit statistics and predictive uncertainty band, while the model simulated the soil moisture with slightly higher accuracy. As expected, emissions were higher from the plots with greater grazing intensity. Scenario analysis showed that the N2O emissions with the recommended fertilizer rate would dominate the emissions from the projected wetter and warmer future. The combined effects of fertilization and wetter and warmer climate scenarios would increase the current N2O emission levels by more than sixfold, which would be comparable to current emission levels from agricultural soils in similar regions.
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Affiliation(s)
- Narayan Kumar Shrestha
- Athabasca River Basin Research Institute (ARBRI), Athabasca University, University Drive, Athabasca, Alberta, T9S 3A3, Canada
| | - Ben W Thomas
- Agriculture and Agri-Food Canada, Agassiz Research and Development Centre, 6947 Highway 7, Agassiz, British Columbia, V0M 1A0, Canada
| | - Xinzhong Du
- Athabasca River Basin Research Institute (ARBRI), Athabasca University, University Drive, Athabasca, Alberta, T9S 3A3, Canada
| | - Xiying Hao
- Agriculture and Agri-Food Canada, Lethbridge Research and Development Centre, 1st Avenue South, Lethbridge, Alberta, T1J 4B1, Canada
| | - Junye Wang
- Athabasca River Basin Research Institute (ARBRI), Athabasca University, University Drive, Athabasca, Alberta, T9S 3A3, Canada.
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Sanou L, Zida D, Savadogo P, Thiombiano A. Comparison of aboveground vegetation and soil seed bank composition at sites of different grazing intensity around a savanna-woodland watering point in West Africa. J Plant Res 2018; 131:773-788. [PMID: 29948487 DOI: 10.1007/s10265-018-1048-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 05/10/2018] [Indexed: 06/08/2023]
Abstract
Grazing removes a plant's aboveground vegetative and reproductive tissues and can modify the soil seed bank, potentially impacting the restoration of preferred species. Knowledge about aboveground vegetation and species composition of soil seed bank and the processes that contribute to vegetation recovery on and surrounding watering points subjected to grazing is lacking. Successful restoration strategies hinge on addressing these knowledge gaps. We assessed the effects of livestock grazing on aboveground vegetation and soil seed bank characteristics along a river bank and surrounding areas subject to different grazing intensities and draw implications for restoration. Plots (50 × 50 m) were established along five transects representing differing levels of grazing intensity. Soil samples were taken from three layers within each plot to determine soil properties and species composition of soil seed bank using the seedling emergence method. Heavy grazing resulted in the disappearance of perennial grasses, a reduction in species diversity and a decrease in soil nutrients with increased soil depth. Overall, the similarity between the extant aboveground vegetation and flora within the soil seed bank was low. The soil seed bank was dominated by herbaceous species and two woody species, suggesting that many woody species are not accumulating in the soil. With increasing soil depth, the seed density and richness declined. Canonical correspondence analyses (CCAs) showed that emerged seedlings from the soil seed bank were significantly influenced by soil carbon, organic matter, total nitrogen, total potassium and soil cation exchange capacity. This finding suggests that current grazing practices have a negative impact on the vegetation surrounding watering points; hence there is a need for improved grazing management strategies and vegetation restoration in these areas. The soil seed bank alone cannot restore degraded river banks; active transfer of propagules from adjacent undisturbed forest areas is essential.
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Affiliation(s)
- Lassina Sanou
- Département Environnement et Forêts, Centre National de la Recherche Scientifique et Technologique, INERA, BP 7047, Ouagadougou 03, Burkina Faso.
- Unité de Formation et de Recherche en Sciences de la Vie et de la Terre/Laboratoire de Biologie et Ecologie Végétales (UFR/SVT), Université Ouaga I Pr Joseph Ki-Zerbo, Ouagadougou, Burkina Faso.
| | - Didier Zida
- Département Environnement et Forêts, Centre National de la Recherche Scientifique et Technologique, INERA, BP 7047, Ouagadougou 03, Burkina Faso
| | - Patrice Savadogo
- West and Central Africa Regional Office, Sahel Node, World Agroforestry Centre (ICRAF), BP E5118, Bamako, Mali
| | - Adjima Thiombiano
- Unité de Formation et de Recherche en Sciences de la Vie et de la Terre/Laboratoire de Biologie et Ecologie Végétales (UFR/SVT), Université Ouaga I Pr Joseph Ki-Zerbo, Ouagadougou, Burkina Faso
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Pan H, Liu H, Liu Y, Zhang Q, Luo Y, Liu X, Liu Y, Xu J, Di H, Li Y. Understanding the relationships between grazing intensity and the distribution of nitrifying communities in grassland soils. Sci Total Environ 2018; 634:1157-1164. [PMID: 29660872 DOI: 10.1016/j.scitotenv.2018.04.117] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 04/07/2018] [Accepted: 04/08/2018] [Indexed: 06/08/2023]
Abstract
Nitrifying microbes are of critical importance in regulating efficient nitrogen (N) cycling, which plays a crucial role in plant productivity and maintaining soil sustainability. Long-term different intensities of grazing can strongly influence the microbial communities, while our understanding of the complex nitrifying community in the grazed grassland soil environment is still limited. To investigate whether and how long-term grazing with different intensities influence soil nitrifying communities, high-throughput sequencing and quantitative PCR analyses were performed on soil samples from permanent grassland soils under four grazing intensities: 0 (G0), 1.5 (G1), 6 (G2) and 9 (G3) sheepha-1. Results showed that the G3 treatment significantly reduced the soil nutrient content and increased the soil bulk density, changes that are not sustainable in the long run. The G1 treatment, on the other hand, significantly increased the soil nutrient content and would improve soil fertility. Some functional microbes were specifically enriched after long term grazing, like Nitrospirae (phylum) to Nitrospira (class) in the G2 samples and Chromatiales (order) to Nitrosococcus (genus) in the G3 soils. The numerically dominant Nitrosococcus watsonii lineage of ammonia oxidizing bacteria (AOB) was observed in this grassland soil. The redundancy analysis (RDA) together with the structural equation modeling (SEM) analysis showed that grazing intensity was important in mediating the distribution of soil microorganisms and affected nitrifying communities by impacting soil physicochemical characteristics (e.g., bulk density, NH4+-N). These results showed the shifts of nitrifying communities across different grazing intensities, and could aid in the determination of an optimal grazing intensity for these grazed grassland soils.
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Affiliation(s)
- Hong Pan
- Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Haiyang Liu
- Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Yaowei Liu
- Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Qichun Zhang
- Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Hangzhou 310058, China
| | - Yu Luo
- Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Hangzhou 310058, China
| | - Xingmei Liu
- Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Hangzhou 310058, China
| | - Yimeng Liu
- School of Economics and Resource Management, Beijing Normal University, Beijing 100875, China
| | - Jianming Xu
- Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Hangzhou 310058, China
| | - Hongjie Di
- Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Hangzhou 310058, China
| | - Yong Li
- Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Hangzhou 310058, China.
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Abdalla M, Hastings A, Chadwick D, Jones D, Evans C, Jones M, Rees R, Smith P. Critical review of the impacts of grazing intensity on soil organic carbon storage and other soil quality indicators in extensively managed grasslands. Agric Ecosyst Environ 2018; 253:62-81. [PMID: 29398743 PMCID: PMC5727677 DOI: 10.1016/j.agee.2017.10.023] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Livestock grazing intensity (GI) is thought to have a major impact on soil organic carbon (SOC) storage and soil quality indicators in grassland agroecosystems. To critically investigate this, we conducted a global review and meta-analysis of 83 studies of extensive grazing, covering 164 sites across different countries and climatic zones. Unlike previous published reviews we normalized the SOC and total nitrogen (TN) data to a 30 cm depth to be compatible with IPCC guidelines. We also calculated a normalized GI and divided the data into four main groups depending on the regional climate (dry warm, DW; dry cool, DC; moist warm, MW; moist cool, MC). Our results show that taken across all climatic zones and GIs, grazing (below the carrying capacity of the systems) results in a decrease in SOC storage, although its impact on SOC is climate-dependent. When assessed for different regional climates, all GI levels increased SOC stocks under the MW climate (+7.6%) whilst there were reductions under the MC climate (-19%). Under the DW and DC climates, only the low (+5.8%) and low to medium (+16.1%) grazing intensities, respectively, were associated with increased SOC stocks. High GI significantly increased SOC for C4-dominated grassland compared to C3-dominated grassland and C3-C4 mixed grasslands. It was also associated with significant increases in TN and bulk density but had no effect on soil pH. To protect grassland soils from degradation, we recommend that GI and management practices should be optimized according to climate region and grassland type (C3, C4 or C3-C4 mixed).
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Affiliation(s)
- M. Abdalla
- Institute of Biological and Environmental Sciences, School of Biological Sciences, University of Aberdeen, Aberdeen, AB24 3UU, UK
- Corresponding author at: Institute of Biological and Environmental Sciences, School of Biological, Sciences, University of Aberdeen, 23 St. Machar Drive, Aberdeen, AB24 3UU, UK.Institute of Biological and Environmental SciencesSchool of Biological SciencesUniversity of AberdeenAberdeenAB24 3UUUK
| | - A. Hastings
- Institute of Biological and Environmental Sciences, School of Biological Sciences, University of Aberdeen, Aberdeen, AB24 3UU, UK
| | - D.R. Chadwick
- School of Environment, Natural Resources and Geography, Bangor University, Bangor, Gwynedd, LL57 2UW, UK
| | - D.L. Jones
- School of Environment, Natural Resources and Geography, Bangor University, Bangor, Gwynedd, LL57 2UW, UK
| | - C.D. Evans
- School of Environment, Natural Resources and Geography, Bangor University, Bangor, Gwynedd, LL57 2UW, UK
| | - M.B. Jones
- Department of Botany, School of Natural Sciences, Trinity College Dublin, Dublin 2, Ireland
| | - R.M. Rees
- Scotland’s Rural College (SRUC) Edinburgh, West Mains Road, Edinburgh, EH93JG, UK
| | - P. Smith
- Institute of Biological and Environmental Sciences, School of Biological Sciences, University of Aberdeen, Aberdeen, AB24 3UU, UK
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Oja J, Vahtra J, Bahram M, Kohout P, Kull T, Rannap R, Kõljalg U, Tedersoo L. Local-scale spatial structure and community composition of orchid mycorrhizal fungi in semi-natural grasslands. Mycorrhiza 2017; 27:355-367. [PMID: 28039600 DOI: 10.1007/s00572-016-0755-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Accepted: 11/30/2016] [Indexed: 05/20/2023]
Abstract
Orchid mycorrhizal (OrM) fungi play a crucial role in the ontogeny of orchids, yet little is known about how the structure of OrM fungal communities varies with space and environmental factors. Previous studies suggest that within orchid patches, the distance to adult orchids may affect the abundance of OrM fungi. Many orchid species grow in species-rich temperate semi-natural grasslands, the persistence of which depends on moderate physical disturbances, such as grazing and mowing. The aim of this study was to test whether the diversity, structure and composition of OrM fungal community are influenced by the orchid patches and management intensity in semi-natural grasslands. We detected putative OrM fungi from 0 to 32 m away from the patches of host orchid species (Orchis militaris and Platanthera chlorantha) in 21 semi-natural calcareous grasslands using pyrosequencing. In addition, we assessed different ecological conditions in semi-natural grasslands but primarily focused on the effect of grazing intensity on OrM fungal communities in soil. We found that investigated orchid species were mostly associated with Ceratobasidiaceae and Tulasnellaceae and, to a lesser extent, with Sebacinales. Of all the examined factors, the intensity of grazing explained the largest proportion of variation in OrM fungal as well as total fungal community composition in soil. Spatial analyses showed limited evidence for spatial clustering of OrM fungi and their dependence on host orchids. Our results indicate that habitat management can shape OrM fungal communities, and the spatial distribution of these fungi appears to be weakly structured outside the orchid patches.
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Affiliation(s)
- Jane Oja
- Institute of Ecology and Earth Sciences, University of Tartu, 14A Ravila, 50411, Tartu, Estonia.
| | - Johanna Vahtra
- Institute of Ecology and Earth Sciences, University of Tartu, 14A Ravila, 50411, Tartu, Estonia
| | - Mohammad Bahram
- Institute of Ecology and Earth Sciences, University of Tartu, 14A Ravila, 50411, Tartu, Estonia
- Department of Organismal Biology, Evolutionary Biology Centre, Uppsala University, SE 75236, Uppsala, Sweden
| | - Petr Kohout
- Institute of Ecology and Earth Sciences, University of Tartu, 14A Ravila, 50411, Tartu, Estonia
- Institute of Botany, Academy of Sciences of the Czech Republic, 252 43, Průhonice, Czech Republic
- Department of Experimental Plant Biology, Faculty of Science, Charles University, CZ-128 01, Prague 2, Czech Republic
| | - Tiiu Kull
- Institute of Agricultural and Environmental Sciences Estonian, University of Life Sciences, 5 Kreutzwaldi, 51014, Tartu, Estonia
| | - Riinu Rannap
- Institute of Ecology and Earth Sciences, University of Tartu, 46 Vanemuise, 51014, Tartu, Estonia
| | - Urmas Kõljalg
- Institute of Ecology and Earth Sciences, University of Tartu, 14A Ravila, 50411, Tartu, Estonia
| | - Leho Tedersoo
- Institute of Ecology and Earth Sciences, University of Tartu, 14A Ravila, 50411, Tartu, Estonia
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Yang Z, Xiong W, Xu Y, Jiang L, Zhu E, Zhan W, He Y, Zhu D, Zhu Q, Peng C, Chen H. Soil properties and species composition under different grazing intensity in an alpine meadow on the eastern Tibetan Plateau, China. Environ Monit Assess 2016; 188:678. [PMID: 27858261 DOI: 10.1007/s10661-016-5663-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 10/31/2016] [Indexed: 05/12/2023]
Abstract
As the main form of land use and human disturbance of grassland, livestock grazing has great influences on the soil resources and plant communities. This study observed the variation of soil properties and community characteristics of four treatments of different grazing intensity (no grazing, UG; light grazing, LG; moderate grazing, MG; and heavy grazing, HG) in an alpine meadow of Sichuan Province on the northeastern margin of the Tibetan Plateau. The results showed that grazing increased the pH, soil bulk density (BD), and contents of total carbon (TC) and total nitrogen (TN), and the BD increased while the others decreased with the grazing intensity. At the community level, with the increase of the grazing intensity, the vegetation coverage (R 2 = 0.61, P < 0.001), mean height of community (R 2 = 0.37, P < 0.001), aboveground biomass (R 2 = 0.54, P < 0.001), litter biomass (R 2 = 0.84, P < 0.001), and percentage of aboveground biomass of palatable grasses to total biomass (R 2 = 0.74, P < 0.001) significantly decreased, while the belowground biomass (R 2 = 0.72, P < 0.001) and the root/shoot (R/S) ratio (R 2 = 0.65, P < 0.001) increased. The species richness was the greatest at LG and the total biomass at UG. With grazing, the dominant species of the plant community shifted from palatable grasses (Gramineae and Cyperaceae) to unpalatable grasses (Compositae and Ranunculaceae). Based on the results, LG may be the optimal grassland management mode to be used in the long time in the alpine meadow of the Tibetan Plateau.
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Affiliation(s)
- Zhen'an Yang
- Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, College of Forestry, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, Sichuan, 610041, People's Republic of China
| | - Wan Xiong
- Chinese Journal of Applied and Environmental Biology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, Sichuan, 610041, People's Republic of China
| | - Yingyi Xu
- Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, College of Forestry, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, Sichuan, 610041, People's Republic of China
| | - Lin Jiang
- Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, College of Forestry, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, Sichuan, 610041, People's Republic of China
| | - Erxiong Zhu
- Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, College of Forestry, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, Sichuan, 610041, People's Republic of China
| | - Wei Zhan
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, Sichuan, 610041, People's Republic of China
| | - Yixin He
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, Sichuan, 610041, People's Republic of China
| | - Dan Zhu
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, Sichuan, 610041, People's Republic of China
| | - Qiuan Zhu
- Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, College of Forestry, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
| | - Changhui Peng
- Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, College of Forestry, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
- Center of CEE/ESCER Biology Science Department, University of Quebec at Montreal, C3H3P8, Montreal, Canada
| | - Huai Chen
- Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, College of Forestry, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China.
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, Sichuan, 610041, People's Republic of China.
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Tessema ZK, de Boer WF, Prins HHT. Changes in grass plant populations and temporal soil seed bank dynamics in a semi-arid African savanna: Implications for restoration. J Environ Manage 2016; 182:166-175. [PMID: 27472053 DOI: 10.1016/j.jenvman.2016.07.057] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 07/12/2016] [Accepted: 07/17/2016] [Indexed: 06/06/2023]
Abstract
The re-colonization or recovery of grass species after disappearance due to heavy grazing depends on the presence of persistent soil seed banks that might be accumulated over time from the aboveground vegetation. Moreover, successful plant recruitment is a function of seed production, seed germination and seedling survival, which can be mechanistically understood through studying the life cycle processes of grass species populations under field conditions. Therefore, we studied the number of germinable seeds, species richness and life-forms in the soil seed banks under light and heavy grazing conditions, and the changes in grass species populations in a semi-arid savanna of Ethiopia. Accordingly, a total of 103 species (15 perennial and 29 annual grasses, 6 legumes, 52 forbs and 1 woody species) emerged from the soil samples collected. Lightly grazed sites had a higher seed density compared with heavily grazed sites. The seed density increased over the first three months of soil sampling and decreased thereafter. Perennial grasses dominated the light grazing sites, whereas annual species dominated the heavily grazed sites, indicating that perennial grasses were replaced by annual species in the soil seed bank through grazing. The mean mortality rate from the seedling stage to adult plants was 65%. The seed-to-seedling stage was found to be the most critical transitional stage for grass survival. High seedling mortality in the aboveground vegetation and depletion of seeds in the soil seed banks as a result of sustained heavy grazing can lead to local extinction and disappearance of perennial grasses in semi-arid Ethiopian savannas.
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Affiliation(s)
- Zewdu K Tessema
- Rangeland Ecology and Biodiversity Program, School of Animal and Range Sciences, Haramaya University, PO Box 138, Dire Dawa, Ethiopia.
| | - Willem F de Boer
- Resource Ecology Group, Wageningen University, Droevendaalsesteeg 3a, 6708PB, Wageningen, The Netherlands
| | - Herbert H T Prins
- Resource Ecology Group, Wageningen University, Droevendaalsesteeg 3a, 6708PB, Wageningen, The Netherlands
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Navarrete D, Sitch S, Aragão LEOC, Pedroni L, Duque A. Conversion from forests to pastures in the Colombian Amazon leads to differences in dead wood dynamics depending on land management practices. J Environ Manage 2016; 171:42-51. [PMID: 26874613 DOI: 10.1016/j.jenvman.2016.01.037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Revised: 01/26/2016] [Accepted: 01/29/2016] [Indexed: 06/05/2023]
Abstract
Dead wood, composed of coarse standing and fallen woody debris (CWD), is an important carbon (C) pool in tropical forests and its accounting is needed to reduce uncertainties within the strategies to mitigate climate change by reducing deforestation and forest degradation (REDD+). To date, information on CWD stocks in tropical forests is scarce and effects of land-cover conversion and land management practices on CWD dynamics remain largely unexplored. Here we present estimates on CWD stocks in primary forests in the Colombian Amazon and their dynamics along 20 years of forest-to-pasture conversion in two sub-regions with different management practices during pasture establishment: high-grazing intensity (HG) and low-grazing intensity (LG) sub-regions. Two 20-year-old chronosequences describing the forest-to-pasture conversion were identified in both sub-regions. The line-intersect and the plot-based methods were used to estimate fallen and standing CWD stocks, respectively. Total necromass in primary forests was similar between both sub-regions (35.6 ± 5.8 Mg ha(-1) in HG and 37.0 ± 7.4 Mg ha(-1) in LG). An increase of ∼124% in CWD stocks followed by a reduction to values close to those at the intact forests were registered after slash-and-burn practice was implemented in both sub-regions during the first two years of forest-to-pasture conversion. Implementation of machinery after using fire in HG pastures led to a reduction of 82% in CWD stocks during the second and fifth years of pasture establishment, compared to a decrease of 41% during the same period in LG where mechanization is not implemented. Finally, average necromass 20 years after forest-to-pasture conversion decreased to 3.5 ± 1.4 Mg ha(-1) in HG and 9.3 ± 3.5 Mg ha(-1) in LG, representing a total reduction of between 90% and 75% in each sub-region, respectively. These results highlight the importance of low-grazing intensity management practices during ranching activities in the Colombian Amazon to reduce C emissions associated with land-cover change from forest to pasture.
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Affiliation(s)
- Diego Navarrete
- Department of Geography, College of Life and Environmental Sciences, University of Exeter, Rennes Drive, Exeter EX4 4RJ, UK.
| | - Stephen Sitch
- Department of Geography, College of Life and Environmental Sciences, University of Exeter, Rennes Drive, Exeter EX4 4RJ, UK
| | - Luiz E O C Aragão
- Department of Geography, College of Life and Environmental Sciences, University of Exeter, Rennes Drive, Exeter EX4 4RJ, UK; Remote Sensing Division, National Institute for Space Research, Av. dos Astronautas, 1758, 12227-010, São José dos Campos, São Paulo, Brazil
| | - Lucio Pedroni
- Carbon Decisions International, Residencial la Castilla, de la primera entrada, 6ta casa a mano derecha, Paraíso de Cartago, Costa Rica
| | - Alvaro Duque
- Departamento de Ciencias Forestales, Universidad Nacional de Colombia - Sede Medellín, Medellín, Colombia
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