Our cautious estimation indicates that the global extent of shifting cultivation, including currently cultivated fields and all stages of fallows, may amount to roughly 280 Mha, with the largest share in Africa, followed by the Americas and Asia. The period of cultivation is usually terminated when the soil shows signs of exhaustion or, more commonly, when the field is overrun by weeds. This figure was elaborated by the first author using ArcGIS 10.4. https://doi.org/10.1371/journal.pone.0184479.g007. Investigation, Writing original draft, Shifting cultivation has often been blamed as the main cause of deforestation and forest degradation [911,14,15], but evidence is growing that when shifting cultivation is discontinued, it is often replaced by intensified land uses with higher environmental impacts [16,17]. Department of Geographical Sciences, University of Maryland, College Park, United States of America, Roles Describes the cultivation systems employed and the problems generated erosion, burning, harm to indigenous plants and animals. We estimate that shifting cultivation landscapes currently cover roughly 280 million hectares worldwide, including both cultivated fields and fallows. This left us with 2,817 one-degree cells, which we then further investigated. here. PLOS ONE promises fair, rigorous peer review, Writing review & editing, Affiliation Our point of departure is a global map of the distribution of primitive subsistence agriculture produced by Butler in 1980 [13], a visual inspection of the distribution of shifting cultivation based on the 20002014 Global Forest Change (GFC) data set [8] and very highresolution satellite imagery, as well as an expert survey. There was a bias towards responses from researchers who worked in Southeast Asia (see Fig 3); but this is also the world region where most research on shifting cultivation has been done, whereas Africa has the fewest studies and is clearly under-represented in light of the considerable occurrence of shifting cultivation there [17,44]. The red hatching in (B) indicates the 1/100 degree cells that were classified as having shifting cultivation. Farmers will have to shift what they grow and how they grow it to keep up with an expanding population. Ecological Implications of Shifting Cultivation | SpringerLink Institute of Geography, University of Bern, Bern, Switzerland, Trends in humid tropical Africa vary widely. [3037]) would be insufficient, as they only cover very few of our one-degree cells and are not representative globally. To get a first estimation of the occurrence of shifting cultivation, we classified each cell under investigation into one of five shifting-cultivation occurrence classes: none, very low, low, moderate, or high. We have nonetheless ventured to display our estimates in predictive maps because they are based on a spatially explicit analysis in 2010. Based on existing data and knowledge, we have made a first attempt at estimating possible future trends in the distribution of shifting cultivation until 2090. The map shows large areas under such agriculture in Africa, tropical Central and South America, and Southeast Asia. South America shows mixed trends: Areas under shifting cultivation have clearly decreased in the southern Brazilian Amazon, whereas survey responses indicate that they are expanding in other parts of the Brazilian Amazon and in Peru. northern Zambia and in the Democratic Republic of the Congo), parts of southeastern Africa (e.g. Yes While an area approximation of actual shifting cultivation landscapes based on our analysis is difficult due to the estimated and not measured shared of shifting cultivation of each one-degree cell we believe that, given the high accuracy of this estimation (see Table 2), a conservative estimate can nonetheless be derived by visually inspecting the cells and allocating reasonable shares of shifting cultivation landscape (currently cultivated fields plus all stages of fallows) to them as described in the methods section. (2017) A global view of shifting cultivation: Recent, current, and future extent. To stress the interactions between society and the environment, the driving forces (D), pressures (P), states (S), impacts (I), and response (R) (DPSIR) framework approach . Shifting cultivation: more than a means of livelihood A global view of shifting cultivation: Recent, current, and future But soil health is negatively impacted by industrial agriculture practices like monocropping, synthetic fertilizers, pesticides and more. The difference between the Butler mapwhich is presumably based on studies dating from the 1960s and 1970s [13]and our own current investigation around 2010 is displayed in Fig 6. The effects on seasons of a changing climate are already being seen across the country and vary region to region: temperatures have risen across seasons, growing seasons have become longer, precipitation patterns have changed, and extreme precipitation events have increased in frequency and severity. One of the most obvious consequences is the depletion of aquifers, river systems, and downstream ground water. If the survey provided information about when (i.e. What is shifting cultivation? What are its disadvantages? - Toppr From this, we excluded regions where shifting cultivation can safely be assumed to not have been present for centuries (e.g. The areas newly classified as having shifting cultivation (blue in Fig 6) are more likely to have been missed in the Butler map than to represent actual new areas under shifting cultivation, as many of these regions are well known to still have significant shifting cultivation landscapes. b. Writing review & editing, Roles This figure was elaborated by the first author using ArcGIS 10.4. https://doi.org/10.1371/journal.pone.0184479.g005. - Indicate shifting cultivation area changes in the following periods of the past (no change, expansion, decline, disappearance): 19001970; 19702000; 20002015. This number certainly requires further validation before it can be claimed to be an adequate estimate of the global area under shifting cultivation. Flooding, changing seasons and other weather changes impact the growing seasons of specific crops and could cause more and more damage to outdoor crops, driving some food production indoors and spiking prices at the same time. Our review of the more recent literature revealed surprisingly few studies containing regional or global estimates of areas under shifting cultivation. Nevertheless, shifting agriculture is an adaptation to tropical soil conditions in regions where long-term, continued cultivation of the same field, without advanced techniques of soil conservation and the use of fertilizers, would be extremely detrimental to the fertility of the land. In some specific areas, especially in Central Africa, it is likely to increase over the next decade before it begins to decline. According to Olofsson et al. Cultivation (tillage) is a practice that has been introduced to Australia from Europe by our farming pioneers. Although the areas shown on the map also include non-shifting forms of subsistence agriculture, it is reasonable to assume that shifting cultivation predominated in the humid and sub-humid tropics, which are the main focus of the present study. Causes and consequences of shifting cultivation and its - Springer It received 1 point in Simran IAS Academy on Instagram: "#Learnbymaps is here to explain you Maps created in QGIS 2.16. https://doi.org/10.1371/journal.pone.0184479.g002. However, we found that its occurrence in most one-degree cells, where it existed, was fairly limited, with roughly 85% of these cells showing occurrence levels below 20% (currently cultivated fields and all stages of fallows). Two steps enabled us to gain insights into larger recent (last 40 to 50 years) trends in the development of the global area under shifting cultivation. However, the occurrence of shifting cultivation within most of the individual one-degree cells is very low, meaning that it is a minor component of the overall landscape. If and when the occurrence of shifting cultivation in a grid cell fell below 5% (mean value for very low), shifting cultivation was assumed to disappear in that grid cell. The excessive growth (or bloom) of algae and plankton in a water body are indicators of this process. [68]). Shifting cultivation tends to persist when population density is low and when options for agricultural development or alternative livelihoods are limited [22,70,71]. They write new content and verify and edit content received from contributors. Livestock may be at risk, both directly from heat stress and indirectly from reduced quality of their food supply. - Myanmar: Shifting cultivation is estimated to mostly disappear sometime between 2060 and 2090 if conflicts between union government and ethnic armed groups are resolved. It coincided with the end of the last ice age and the beginning of the. SCIplanet - Shifting Cultivation Globally, sixty-two per cent of the investigated one-degree cells showed signs of shifting cultivation, with surprisingly similar shares across the 3 regions, ranging between 59 and 65% (Table 1) In absolute terms, the majority of cells with shifting cultivation are located in the Americas and Africa (almost 78%). Yucatan Peninsula [66], northern South America (e.g. Our preliminary estimated for the future indicate that the area under shifting cultivation is expected to shrink considerably over the next decades. Furthermore we wish to express our gratitude to the two reviewers as well as the editor for the very useful comments and inputs. The evil effects of shifting cultivation are devastating and far reaching in degrading the environment and ecology of this region. The number of estimates of areas under shifting cultivation at regional and national scales in the literature is also very limited. Most plants and animals live in areas with very specific climate conditions, such as temperature and rainfall patterns, that enable them to thrive. With 62% of the investigated one-degree cells in the humid and sub-humid tropics currently showing signs of shifting cultivationthe majority in the Americas (41%) and Africa (37%)this form of cultivation remains widespread, and it would be wrong to speak of its general global demise in the last decades. Climate change will bring more frequent and severe extreme weather events, including extreme precipitation, wind disturbance, heat waves, and drought. Department of Geosciences and Natural Resource Management, University of Copenhagen, Copenhagen K, Denmark, Roles Of the remaining 225 authors, 72 responded and 49 provided usable information (see S1 File). Deforestation - Causes, effects, Control of Deforestation with Videos Nonetheless, it is more evidence-based than the 1,000 Mha of unclear origin that are repeatedly cited in the literature (e.g. [52]; the latter source, however, does not provide this information, so the 1,000 Mha claim seems to be unfounded. Shifting cultivation decreases the activities of useful microorganisms found in the soil. Fig 1B to Fig 1E show examples of different zoom levels used to decide whether the pattern in the GFC data is indeed related to shifting cultivation Fig 1E (showing pattern of clearing for the current year of cultivation and different stages of fallow) or not Fig 1D (larger scale clearings with young rubber). We initiated occurrence at a one-degree resolution in 2010 (base year) at the mean of the above-stated ranges for each occurrence category in the assessment of current landscape with signs of shifting cultivation based on the GFC data (c.f. Cultivation was also a traditional form of weed control. Shifting Cultivation at a Crossroads: Drivers and Outcomes of Recent Moreover, it is not possible to know in detail how the respondents arrived at their assessment of past and future extents of shifting cultivation. The analysis presented is primarily qualitative with a supplementary quantitative analysis of the causes of forest . No, PLOS is a nonprofit 501(c)(3) corporation, #C2354500, based in San Francisco, California, US, Corrections, Expressions of Concern, and Retractions, https://doi.org/10.1371/journal.pone.0184479, ftp://ftp.fao.org/docrep/fao/003/y1860e/y1860e00.pdf, https://www.cia.gov/library/publications/the-world-factbook/geos/cg.html. Methane emissions are driving climate change. Here's how to - UNEP We did not perform any detailed spatial delineation of the actual area under shifting cultivation, as the goal of our study was to provide a global one degreegridded product. Industrialized agriculture is highly concentrated and mechanized, relying on chemical inputs like fertilizers, pesticides and non-therapeutic antibiotics. Deforestation: Definition, Causes and Impacts - Embibe Shifting Cultivation Shifting Cultivation Agricultural Geography Agricultural Hearths Agricultural Production Regions Agricultural Revolutions Agriculture and Climate Agriculture and Pollution Agrochemicals Community Supported Agriculture Extensive Farming Feeding the World Food Desert Food Insecurity Food Movements Green Revolution While our estimates are based on non-automated methods and expert information from different parts of the world, we argue that our work nonetheless advances the state of knowledge considerably, especially with regard to earth system modeling scenarios, which have proved sensitive to the inclusion of shifting cultivation and up to now have used shifting cultivation data based on a hand drawn map from the 1980s. First, an area of fallow forest is cleared for cultivation. These negative effects can be identified in the form of localized deforestation, soil and nutrient loss, and invasion by weeds and other species. Its authors detected changes in what they call the rural complex for the period from 2000 to 2010. However, sustainable agriculture, which uses methods that protect the environment, public . PLoS ONE 12(9): This trend, which was also identified by van Vliet et al. Shifting cultivation in Mizoram, India: An empirical study of its [17], contrasts with developments in other parts of Africa, where decreases and the disappearance of areas under shifting cultivation have dominated over the last two decades. Formal analysis, This figure was elaborated by the first author using ArcGIS 10.4. https://doi.org/10.1371/journal.pone.0184479.g003. Validation, (Fig 2DA) and (Fig 2E): The white line grid marks the 1/100 degree cells used as basic unit for the validation data. We compared this result to Butlers (1980) binary (presence or absence) map of shifting cultivation, gridded into one-degree cells. After analyzing the spatially differentiated changes between the status in the 1960s to 1970s as shown in the Butler map and our data for 2010 (Fig 6), we combined them with data from our expert survey about changes in areas under shifting cultivation between 1970 to 2000 and 2000 to 2010 as well as with information from the literature. As growing only one kind of plant on the same piece of farmland depletes and exhausts the soil by depriving it of the biodiversity, farmers tend to artificially boost the fertility of their impacted fields by applying chemical fertilizers. https://doi.org/10.1371/journal.pone.0184479.t003. While every effort has been made to follow citation style rules, there may be some discrepancies. Degradation is the gradual decline of forested areas that does not result in complete deforestation. Copyright: 2017 Heinimann et al. The Neolithic Revolutionfacts and information - National Geographic The respondents were asked to estimate the current spatial extent of shifting cultivation as well as past and future trends in the development of this extent in their area of interest. https://doi.org/10.1371/journal.pone.0184479.t001. For example, data for Laos indicate between 2 and over 6 Mha, while more recent figures based on remote sensing (multi-temporal Landsat) for northern Laoswhere the largest share of shifting cultivation in the country is foundare 3.1 Mha [33] and 2.6 Mha [34]. Shifting cultivation in general, is a system of farming in which fields are prepared by cutting down the natural vegetations. Regarding Central and South America, the only available source [57] used the secondary forest class as defined in FAOs Forest Resource Assessment 1990 [58] as a proxy and stated the area under shifting cultivation to be 165 Mha. We limited the search to the period from 2005 to 2016 partly because we were interested in the most recent data on the extent of shifting cultivation as a basis for generating a map showing the contemporary situation (around the year 2010); the other reason was that we expected many recent reports on areas under shifting cultivation to rely on previously published data, which would enable targeted backtracking through the literature all the way to the original sources. Shifting Cultivation: Definition & Examples | StudySmarter We are very grateful to Laura Ebneter, Manuel Abebe, Lukas Wuersch and Boris Fuhrer for their support in interpreting the satellite imagery and to Marlne Tibeault for the language editing. The global shift towards this model of farming in the last sixty years has come with many costs. of Energy, grant number DE-SC0012972, and the Global Land Project Grant from the University of Copenhagen. This approach, however, suffers from the shortcoming that land cover data are of very limited use in estimating land use practices, which is acknowledged by Silva et al. - Indicate how you expect the shifting cultivation occurrences to change in the future for the following periods (no change, expansion, decline, disappearance): 20152030; 20302060; 20602090. In a book called Shifting cultivation policies: Balancing environmental and social sustainability (2017), an outline of the role of government and local institutions in regulating shifting . Based on our expert survey and historical trends we estimate a possible strong decrease in shifting cultivation over the next decades, raising issues of livelihood security and resilience among people currently depending on shifting cultivation. On the other hand, large areas with shifting cultivation in Central Africa, for example in the Democratic Republic of the Congo [36], are strongly under-represented in Silva et al. Our predictions of future extents of shifting cultivation are, of course, speculative. Yes While the literature offers good representations of the major natural land covers and human land uses [68], mosaic landscapes with a dynamic mix of managed and natural land covers often fall through the cracks in global land cover and land use classifications, as these are unable to adequately capture such landscapes dynamic nature and complex spectral signatures [912]. 70% of global freshwater withdrawals are used for agriculture 2. Taking into consideration the stratification criteria, 328 one-degree cells were randomly selected to be validated. It is a form of farming practice that entails clearing a land parcel by felling and burning trees. https://www.britannica.com/topic/shifting-agriculture. Based on the spatio-temporal pattern of the GFC data (different colours denoted different year of clearings) and the patterns of clearing and regrowth in the very high resolution imagery (here Bing), a 1/100-degree cell is being classified as showing shifting cultivation or not. What is Shifting Cultivation? What are its Disadvantages? Biology Q&A
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