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Data extracted in September 2021
Fiche created in December 2023
Note to the reader: This general fiche summarises all the environmental and climate impacts of GRAZING MANAGEMENT found in a review of 31 synthesis papers[1]. These papers were selected from an initial number of 1022 obtained through a systematic literature search strategy, according to the inclusion criteria reported in section 4. The impacts reported here are those for which there is scientific evidence available in published synthesis papers, what does not preclude the farming practice to have other impacts on the environment and climate still not covered by primary studies or by synthesis papers.
The synthesis papers review a number of primary studies ranging from 4 to 287. Therefore, the assessment of impacts relies on a large number of results from the primary studies, obtained mainly in field conditions, or sometimes in lab experiments or from model simulations.
1. DESCRIPTION OF THE FARMING PRACTICE
- Description:
- Grasslands are areas of land predominantly covered by communities of grass-like plants and forbs and may include sparsely occurring trees and shrubs. In the Eurostat classification, percentages of area covered by such canopies are limited to less than 10 % in the case of trees and to less than 20 % in the case of shrubs (i.e., low woody plants capable of reaching heights of up to 5 metres)[2] or shrubs and trees together.[3] However, in the scientific literature reviewed here, grasslands are usually more broadly defined and might not fully meet such canopy limits.
- This review includes a wide variety of grassland types: savannah, grassy deserts, seasonally flooded grasslands, prairies, meadows, pastures, rangelands, salt-marshes, bioenergy perennial grasslands, calcareous grasslands and wooded grasslands. Grasslands differ in terms of: management intensity (natural, semi-natural, improved and intensively managed); management history: permanent and temporary; successional stage (old successional and secondary grasslands); biomes and climates (semi-arid, temperate, tropical, Mediterranean, tundra, alpine, subalpine, artic and subartic).
- Fodder crops are not included as grasslands.
- This review includes interventions in grasslands related to:
- Grazing is a method of animal husbandry in which livestock are allowed to feed outdoors consuming wild vegetation.
- Rotational grazing comprises grazing regimes that incorporate periods of planned rest. In the scientific literature it is also refereed as strategic‐rest grazing.[4]
- Key descriptors:
- For the exploration of the impacts of grazing and grazing intensity, this review explores different grazing intensities: light, moderate and heavy (as reported by authors) as intervention, compared to no grazing or lower grazing intensity as comparator. We assume that the authors of the original individual papers report grazing intensity based on their knowledge of the systems studied, meaning that, for instance, the density intensity considered light in one study system can be high in another. Therefore, grazing intensities across individual studies and synthesis papers can not be compared. No grazing refers to areas with grazing exclusion or where only wild herbivores graze in natural conditions.
- For the exploration of the impacts of rotational grazing, nearby areas with no grazing or continuous grazing are used as comparator.
- The grazing livestock species included in this review are mainly cows, but goats, sheep and domesticated horses and yaks are also included.
- When specified, the effects on biodiversity are explored for plant and animal taxa separately, as their trends differ. In this review, animal biodiversity includes invertebrates (in general, or specific taxa such as spiders, insects or benthic species) and vertebrates (in general, or specific taxa such as birds, mammals, reptiles, amphibians). Plant biodiversity includes vascular and non-vascular plants as well as lichens.
- The review of the impacts of grazing intensities includes spatial and temporal comparisons. Spatial comparisons were simultaneously conducted between nearby grazed and non-grazed areas. Temporal comparisons were conducted in the same area during periods with different grazing intensities.
- For the review of the impacts of grazing intensities, no grazing or lower grazing intensities were always used as comparators.
- This review does not include other management practices conducted in grasslands (i.e, soil amendment and fertilisation, mowing, increasing grass species richness) nor the conversion of other agricultural land uses to grasslands, which are assessed in separate sets of fiches.
2. EFFECTS OF THE FARMING PRACTICE ON CLIMATE AND ENVIRONMENTAL IMPACTS
We reviewed the impacts of different grazing intensities (intervention) on grasslands, compared to grasslands with no grazing or with lower grazing intensity (comparator). In addition, we reviewed the impacts of rotational grazing on grasslands (intervention), compared to grasslands with continuous grazing or with no grazing (comparator).
The table below shows the number of synthesis papers with statistical tests reporting i) a significant difference between the Intervention and the Comparator, that is to say, a significant statistical effect, which can be positive or negative; or ii) a non-statistically significant difference between the Intervention and the Comparator. In addition, we include, if any, the number of synthesis papers reporting relevant results but without statistical test of the effects. Details on the quality assessment of the synthesis papers can be found in the methodology section of this WIKI.
All selected synthesis papers included studies conducted in Europe , and 31 have a quality score higher than 50%.
Table 1: Summary of effects. Number of synthesis papers reporting positive, negative or non-statistically significant effects on environmental and climate impacts. The number of synthesis papers reporting relevant results but without statistical test of the effects are also provided. When not all the synthesis papers reporting an effect are of high quality, the number of synthesis papers with a quality score of at least 50% is indicated in parentheses. Some synthesis papers may report effects for more than one impact, or more than one effect for the same impact.
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| Statistically tested | Non-statistically tested | ||
Impact | Metric | Intervention | Comparator | Significantly positive | Significantly negative | Non-significant | |
Increase Animal production | Animal production | Rotational grazing | Continuous grazing | 1 | 0 | 1 | 0 |
Increase Biodiversity | Animals biodiversity | Grazing | No grazing | 0 | 5 | 5 | 0 |
Heavy/intensive grazing | No grazing or lower grazing intensity | 0 | 2 | 1 | 0 | ||
Light/extensive grazing | No grazing | 0 | 2 | 1 | 0 | ||
Moderate grazing | No grazing | 0 | 0 | 1 | 0 | ||
Increase Biodiversity | Biodiversity (overall) | Grazing | No grazing | 1 | 0 | 0 | 0 |
Heavy/intensive grazing | No grazing or lower grazing intensity | 0 | 2 | 0 | 0 | ||
Light/extensive grazing | No grazing | 2 | 0 | 0 | 0 | ||
Moderate grazing | No grazing or lower grazing intensity | 1 | 1 | 0 | 0 | ||
Increase Biodiversity | Plants biodiversity | Grazing | No grazing | 3 | 1 | 1 | 0 |
Heavy/intensive grazing | No grazing or lower grazing intensity | 0 | 2 | 1 | 0 | ||
Light/extensive grazing | No grazing | 1 | 0 | 0 | 0 | ||
Moderate grazing | No grazing or lower grazing intensity | 1 | 0 | 1 | 0 | ||
Rotational grazing | Continuous grazing | 0 | 0 | 1 | 0 | ||
Rotational grazing | No grazing | 0 | 0 | 1 | 0 | ||
Increase Carbon sequestration | Soil organic carbon | Grazing | No grazing | 0 | 6 | 2 | 0 |
Heavy/intensive grazing | No grazing | 0 | 3 | 0 | 0 | ||
Light/extensive grazing | No grazing | 1 | 0 | 3 | 0 | ||
Moderate grazing | No grazing | 0 | 2 | 2 | 0 | ||
Rotational grazing | Continuous grazing | 1 | 0 | 0 | 0 | ||
Rotational grazing | No grazing | 0 | 0 | 1 | 0 | ||
Decrease GHG emissions | GHG emissions | Heavy/intensive grazing | No grazing | 1 | 1 | 0 | 0 |
Light/extensive grazing | No grazing | 0 | 0 | 1 | 0 | ||
Moderate grazing | No grazing | 0 | 0 | 1 | 0 | ||
Increase Grassland production | Crop yield | Grazing | No grazing | 0 | 3 | 1 | 0 |
Heavy/intensive grazing | No grazing | 0 | 1 | 0 | 0 | ||
Light/extensive grazing | No grazing | 0 | 0 | 1 | 0 | ||
Moderate grazing | No grazing | 0 | 1 | 0 | 0 | ||
Rotational grazing | Continuous grazing | 1 | 0 | 0 | 0 | ||
Rotational grazing | No grazing | 0 | 1 | 0 | 0 | ||
Decrease Pests and diseases | Pests | Grazing | No grazing | 0 | 1 | 0 | 0 |
Increase Pollination | Pollination | Grazing | No grazing | 0 | 0 | 1 | 0 |
Heavy/intensive grazing | No grazing or lower grazing intensity | 0 | 1 | 0 | 0 | ||
Increase Soil biological quality | Soil microorganisms | Grazing | No grazing | 3 | 6 | 2 | 0 |
Heavy/intensive grazing | No grazing | 0 | 4 | 1 | 0 | ||
Light/extensive grazing | No grazing | 1 | 0 | 3 | 0 | ||
Moderate grazing | No grazing | 1 | 1 | 2 | 0 | ||
Increase Soil nutrients | Soil nutrients | Grazing | No grazing | 2 | 5 | 1 | 0 |
Heavy/intensive grazing | No grazing | 0 | 2 | 2 | 0 | ||
Light/extensive grazing | No grazing | 0 | 0 | 3 | 0 | ||
Moderate grazing | No grazing | 1 | 2 | 2 | 0 | ||
Rotational grazing | Continuous grazing | 0 | 0 | 1 | 0 | ||
Rotational grazing | No grazing | 0 | 0 | 1 | 0 | ||
Increase Soil physico-chemical quality | Soil chemical quality | Grazing | No grazing | 0 | 1 | 0 | 0 |
Heavy/intensive grazing | No grazing | 0 | 0 | 1 | 0 | ||
Moderate grazing | No grazing | 0 | 0 | 1 | 0 | ||
Increase Soil water retention | Soil water retention | Grazing | No grazing | 0 | 2 | 0 | 0 |
Heavy/intensive grazing | No grazing | 0 | 2 | 0 | 0 | ||
Light/extensive grazing | No grazing | 0 | 0 | 2 | 0 | ||
Moderate grazing | No grazing | 0 | 0 | 2 | 0 | ||
3. FACTORS INFLUENCING THE EFFECTS ON CLIMATE AND ENVIRONMENTAL IMPACTS
The factors significantly influencing the size and/or direction of the effects on the impacts, according to the synthesis papers included in this review, are reported below. Details about the factors can be found in the summaries of the meta-analyses available in this WIKI.
Table 2: List of factors reported to significantly affect the size and/or direction of the effects on environmental and climate impacts, according to the synthesis papers reviewed. The reference number of the synthesis papers where those factors are explored is given in parentheses.
Impact | Factors |
Animal production | Rest:graze ratio (Ref11) |
Biodiversity | Altitude (Ref9), Artropod order (Ref9), Climate (Ref17), Geographical area (Ref9), Rest:graze ratio (Ref11) and Time from abandonment (Ref9) |
Carbon sequestration | Altitude (Ref7), Animal type (Ref22), Climate (Ref14, Ref22), Grass type (Ref23), Grazing intensity (Ref22, Ref23), Mean annual precipitation (Ref7, Ref23), Mean annual temperature (Ref7, Ref23), Plant type (Ref14), Soil microbial biomass (Ref4), Soil pH (Ref23) and Soil texture (Ref23) |
GHG emissions | Duration of treatment (Ref12) and Precipitation (Ref12) |
Grassland production | Grazing intensity (Ref11), Rest:graze ratio (Ref11) and Soil microbial biomass (Ref4) |
Soil biological quality | Duration of treatment (Ref4, Ref10, Ref21), Grazing intensity (Ref22), Plant type (Ref10, Ref30), Precipitation (Ref10), Soil depht (Ref4, Ref21, Ref22) and Treatment type (Ref30) |
Soil nutrients | Animal type (Ref3, Ref22), Climate (Ref3, Ref22), Grassland type (Ref3), Grazing intensity (Ref3, Ref22), Grazing type (Ref3), Mean annual precipitation (Ref7), Mean annual temperature (Ref7), Soil depht (Ref3) and Soil microbial biomass (Ref4) |
Soil physico-chemical quality | Mean annual precipitation (Ref18), Mean annual precipitation/mean annual potential evapotranspiration (Ref18) and Soil texture (Ref18) |
4. SYSTEMATIC REVIEW SEARCH STRATEGY
Table 3: Systematic review search strategy - methodology and search parameters.
Parameter | Details |
Keywords | WOS: (TS=("grazing*" OR "grassland*" OR "pasture*" OR "rangeland")) AND TS=(("meta-analy*" OR "systematic* review*" OR "evidence map" OR "global synthesis" OR "evidence synthesis" OR "research synthesis")) |
Time reference | No time restriction. |
Databases | Web of Science and Scopus: run on 21 September 2021 |
Exclusion criteria | The main criteria that led to the exclusion of a synthesis paper are: |
5. SYNTHESIS PAPERS INCLUDED IN THE REVIEW
Table 4: List of synthesis papers included in this review. More details can be found in the summaries of the meta-analyses.
Ref Num | Author(s) | Year | Title | Journal | DOI |
Ref1 | Barzan, FR; Bellis, LM; Dardanelli, S | 2021 | Livestock grazing constrains bird abundance and species richness: A global meta-analysis | BASIC AND APPLIED ECOLOGY, 56, 289-298. | 10.1016/j.baae.2021.08.007 |
Ref2 | Oyarzabal, G; Guimaraes, M | 2021 | Friend and foe? The effects of grassland management on global patterns of spider diversity | ECOLOGICAL ENTOMOLOGY, 46(5), 1195-1204. | 10.1111/een.13065 |
Ref3 | Yu, RP; Zhang, WP; Fornara, DA; Li, L | 2021 | Contrasting responses of nitrogen: Phosphorus stoichiometry in plants and soils under grazing: A global meta-analysis | JOURNAL OF APPLIED ECOLOGY, 58(5), 964-975. | 10.1111/1365-2664.13808 |
Ref4 | Zhang, Q; Liu, KS; Shao, XQ; Li, H; He, YX; Sirimuji; Wang, BJ | 2021 | Microbes require a relatively long time to recover in natural succession restoration of degraded grassland ecosystems | ECOLOGICAL INDICATORS, 129, 107881. | 10.1016/j.ecolind.2021.107881 |
Ref5 | Doherty, TS; Balouch, S; Bell, K; Burns, TJ; Feldman, A; Fist, C; Garvey, TF; Jessop, TS; Meiri, S; Driscoll, DA | 2020 | Reptile responses to anthropogenic habitat modification: A global meta-analysis | GLOBAL ECOLOGY AND BIOGEOGRAPHY, 29(7), 1265-1279. | 10.1111/geb.13091 |
Ref6 | Gao, JJ; Carmel, Y | 2020 | A global meta-analysis of grazing effects on plant richness | AGRICULTURE ECOSYSTEMS AND ENVIRONMENT, 302, 107072. | 10.1016/j.agee.2020.107072 |
Ref7 | He, M; Zhou, GY; Yuan, TF; van Groenigen, KJ; Shao, JJ; Zhou, XH | 2020 | Grazing intensity significantly changes the C : N : P stoichiometry in grassland ecosystems | GLOBAL ECOLOGY AND BIOGEOGRAPHY, 29(2), 355-369. | 10.1111/geb.13028 |
Ref8 | Lai, LM; Kumar, S | 2020 | A global meta-analysis of livestock grazing impacts on soil properties | PLOS ONE, 15(8), e0236638. | 10.1371/journal.pone.0236638 |
Ref9 | Sartorello, Y; Pastorino, A; Bogliani, G; Ghidotti, S; Viterbi, R; Cerrato, C | 2020 | The impact of pastoral activities on animal biodiversity in Europe: A systematic review and meta-analysis | JOURNAL FOR NATURE CONSERVATION, 56, 125863. | 10.1016/j.jnc.2020.125863 |
Ref10 | Yang, X; Chen, JS; Shen, Y; Dong, FY; Chen, J | 2020 | Global negative effects of livestock grazing on arbuscular mycorrhizas: A meta-analysis | SCIENCE OF THE TOTAL ENVIRONMENT, 708, 134553. | 10.1016/j.scitotenv.2019.134553 |
Ref11 | McDonald, SE; Lawrence, R; Kendal, L; Rader, R | 2019 | Ecological, biophysical and production effects of incorporating rest into grazing regimes: A global meta-analysis | JOURNAL OF APPLIED ECOLOGY, 56(12), 2723-2731. | 10.1111/1365-2664.13496 |
Ref12 | Tang, SM; Wang, K; Xiang, YZ; Tian, DS; Wang, JS; Liu, YS; Cao, B; Guo, D; Niu, SL | 2019 | Heavy grazing reduces grassland soil greenhouse gas fluxes: A global meta-analysis | SCIENCE OF THE TOTAL ENVIRONMENT, 654, 1218-1224. | 10.1016/j.scitotenv.2018.11.082 |
Ref13 | Wang, C; Tang, YJ | 2019 | A global meta-analyses of the response of multi-taxa diversity to grazing intensity in grasslands | ENVIRONMENTAL RESEARCH LETTERS, 14(11), 114003. | 10.1088/1748-9326/ab4932 |
Ref14 | Abdalla, M; Hastings, A; Chadwick, DR; Jones, DL; Evans, CD; Jones, MB; Rees, RM; Smith, P | 2018 | Critical review of the impacts of grazing intensity on soil organic carbon storage and other soil quality indicators in extensively managed grasslands | AGRICULTURE ECOSYSTEMS AND ENVIRONMENT, 253, 62-81. | 10.1016/j.agee.2017.10.023 |
Ref15 | Byrnes, RC; Eastburn, DJ; Tate, KW; Roche, LM | 2018 | A global meta-analysis of grazing impacts on soil health indicators | JOURNAL OF ENVIRONMENTAL QUALITY, 47(4), 758-765. | 10.2134/jeq2017.08.0313 |
Ref16 | de Lima, DO; Lorini, ML; Vieira, MV | 2018 | Conservation of grasslands and savannas: A meta-analysis on mammalian responses to anthropogenic disturbance | JOURNAL FOR NATURE CONSERVATION, 45, 72-78. | 10.1016/j.jnc.2018.08.008 |
Ref17 | Herrero-Jauregui, C; Oesterheld, M | 2018 | Effects of grazing intensity on plant richness and diversity: A meta-analysis | OIKOS, 127(6), 757-766. | 10.1111/oik.04893 |
Ref18 | Sirimarco, X; Barral, MP; Villarino, SH; Laterra, P | 2018 | Water regulation by grasslands: A global meta-analysis | ECOHYDROLOGY, 11(4), e1934. | 10.1002/eco.1934 |
Ref19 | Davidson, KE; Fowler, MS; Skov, MW; Doerr, SH; Beaumont, N; Griffin, JN | 2017 | Livestock grazing alters multiple ecosystem properties and services in salt marshes: A meta-analysis | JOURNAL OF APPLIED ECOLOGY, 54(5), 1395-1405. | 10.1111/1365-2664.12892 |
Ref20 | Dettenmaier, SJ; Messmer, TA; Hovick, TJ; Dahlgren, DK | 2017 | Effects of livestock grazing on rangeland biodiversity: A meta-analysis of grouse populations | ECOLOGY AND EVOLUTION, 7(19), 7620-7627. | 10.1002/ece3.3287 |
Ref21 | Zhao, FZ; Ren', CJ; Shelton, S; Wang, ZT; Pang, GW; Chen, J; Wang, J | 2017 | Grazing intensity influence soil microbial communities and their implications for soil respiration | AGRICULTURE ECOSYSTEMS AND ENVIRONMENT, 253, 62-81. | 10.1016/j.agee.2017.08.007 |
Ref22 | Zhou, GY; Zhou, XH; He, YH; Shao, JJ; Hu, ZH; Liu, RQ; Zhou, HM; Hosseinibai, S | 2017 | Grazing intensity significantly affects belowground carbon and nitrogen cycling in grassland ecosystems: A meta-analysis | GLOBAL CHANGE BIOLOGY, 23(3), 1167-1179. | 10.1111/gcb.13431 |
Ref23 | Dlamini, P; Chivenge, P; Chaplot, V | 2016 | Overgrazing decreases soil organic carbon stocks the most under dry climates and low soil pH: A meta-analysis shows | AGRICULTURE ECOSYSTEMS AND ENVIRONMENT, 221, 258-269. | 10.1016/j.agee.2016.01.026 |
Ref24 | Jauni, M; Gripenberg, S; Ramula, S | 2015 | Non-native plant species benefit from disturbance: A meta-analysis | OIKOS, 124(2), 122-129. | 10.1111/oik.01416 |
Ref25 | Alkemade, R; Reid, RS; Van Den Berg, M; De Leeuw, J; Jeuken, M | 2013 | Assessing the impacts of livestock production on biodiversity in rangeland ecosystems | PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 110(52), 20900-20905. | 10.1073/pnas.1011013108 |
Ref26 | Bernes, C; Bråthen, KA; Forbes, BC; Hofgaard, A; Moen, J; Speed, JD | 2013 | What are the impacts of reindeer/caribou (Rangifer tarandus L.) on arctic and alpine vegetation? A systematic review protocol | ENVIRONMENTAL EVIDENCE, 4(4), 1-26. | 10.1186/2047-2382-2-6 |
Ref27 | Mcsherry, ME; Ritchie, ME | 2013 | Effects of grazing on grassland soil carbon: A global review | GLOBAL CHANGE BIOLOGY, 19(5), 1347-1357. | 10.1111/gcb.12144 |
Ref28 | Scheper, J; Holzschuh, A; Kuussaari, M; Potts, SG; Rundlf, M; Smith, HG; Kleijn, D | 2013 | Environmental factors driving the effectiveness of European agri-environmental measures in mitigating pollinator loss – a meta-analysis | ECOLOGY LETTERS, 16(7), 912-20. | 10.1111/ele.12128 |
Ref29 | Prieto-Benitez, S; Mendez, M | 2011 | Effects of land management on the abundance and richness of spiders (Araneae): A meta-analysis | BIOLOGICAL CONSERVATION, 144(2), 683-691. | 10.1016/j.biocon.2010.11.024 |
Ref30 | Barto, EK; Rillig, MC | 2010 | Does herbivory really suppress mycorrhiza? A meta-analysis | JOURNAL OF ECOLOGY, 98(4), 745-753. | 10.1111/j.1365-2745.2010.01658.x |
Ref31 | Winfree, R; Aguilar, R; Vazquez, DP; LeBuhn, G; Aizen, MA | 2009 | A meta-analysis of bees' responses to anthropogenic disturbance | ECOLOGY, 90(8), 2068-2076. | 10.1890/08-1245.1 |
Disclaimer: These fiches present a large amount of scientific knowledge synthesised to assess farming practices impacts on the environment, climate and productivity. The European Commission maintains this WIKI to enhance public access to information about its initiatives. Our goal is to keep this information timely and accurate. If errors are brought to our attention, we will try to correct them. However, the Commission accepts no responsibility or liability whatsoever with regard to the information on these fiches and WIKI.
[1] Synthesis research papers include either meta-analysis or systematic reviews with quantitative results. Details can be found in the methodology section of the WIKI.
[2] https://ec.europa.eu/eurostat/statistics-explained/index.php?title=Glossary:Shrubland
[3] https://ec.europa.eu/eurostat/statistics-explained/index.php?title=Glossary:Grassland
[4] McDonald, et al. 2019. Ecological, biophysical and production effects of incorporating rest into grazing regimes: A global meta-analysis. Journal of Applied Ecology 56, 2723–2731.