explain the effects of shifting cultivation on the environment
Climate Impacts on Agriculture and Food Supply - US EPA - Indicate shifting cultivation area changes in the following periods of the past (no change, expansion, decline, disappearance): 19001970; 19702000; 20002015. Data curation, No, Is the Subject Area "Africa" applicable to this article? [24]). [55], citing the Wasteland Atlas [56], estimated the extent of shifting cultivation in the mid-2000s at 5.6 Mha (only area under cultivation), whereas the GLC2000-based estimate is 7.6 Mha [1]. The selection process ensured that all are experts in the field, but there may be disciplinary or personal differences in the way that especially the future of shifting cultivation was assessed. One of the most obvious consequences is the depletion of aquifers, river systems, and downstream ground water. Soil Health is Affected by Industrial Agriculture - FoodPrint For example, many of the commercial or smallholder oil palm and rubber plantations that cover large areas of Southeast Asia today are on land that was formerly used for shifting cultivation [1821]. A global view of shifting cultivation: Recent, current, and future It received 1 point in Our editors will review what youve submitted and determine whether to revise the article. Formal analysis, There is a need to transform shifting cultivation to sustainable intensification. We believe that this represents a significant improvement on the shifting cultivation predictions that have been used so far in global land use models to estimate future greenhouse gas emissions, and we hope that our estimates can be a valuable input for future comparisons between models and international synthesis studies such as the upcoming Coupled Model Intercomparison Project Phase 6 (CMIP6) experiments [27] and the next Assessment Report of the Intergovernmental Panel on Climate Change (IPCC). It is a form of farming practice that entails clearing a land parcel by felling and burning trees. Due to its low productivity and incompatibility with most cash crops, shifting cultivation may lock farmers into 'land use' poverty traps. Mosaic landscapes under shifting cultivation, with their dynamic mix of managed and natural land covers, often fall through the cracks in remote sensingbased land cover and land use classifications, as these are unable to adequately capture such landscapes dynamic nature and complex spectral and spatial signatures. They write new content and verify and edit content received from contributors. These approaches, however, are still in the making and will require substantial resources. Accordingly, they emphasized that the need for global data on annual global gridded land-use transitions from past-to-future presents a large and underdetermined problem [2]. However, adequate prediction of land usebased emissions requires an improved understanding of megatrends in land use systems change [2,5]. The present study is a first step towards a future in which we will know more about the global distribution of shifting cultivation; we hope it opens the door to quantifying shifting cultivations importance for local as well as the global socio-ecological systems. PDF IWGIA - IWGIA - International Work Group for Indigenous Affairs Investigation, The data sources are not entirely clear, but the assessment seems to be based on a number of studies carried out between the end of the 19th century and the late 1950s, along with expert judgement. Agriculture and Its Impact on LandUse, Environment, and Ecosystem The climate of most European countries is wet Fig 1A shows a one-degree square of northern Laos. Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, United States of America, Roles When looking at this comparison, it is important to keep in mind that only full disappearance of shifting cultivation within a one-degree cell will show as a change between the two data sets; gradual decreaseswhich normally precede full disappearanceare not captured if the occurrence of shifting cultivation in the respective cells according to our present estimate remains greater than 5%. What can be the possible positive impacts of shifting cultivation to Department of Geosciences and Natural Resource Management, University of Copenhagen, Copenhagen K, Denmark, Roles No, Is the Subject Area "South America" applicable to this article? This will be useful in improving the characterization of land surface and land use dynamics for earth system models and large-scale carbon and greenhouse gas accounting. To date, we know little about its worldwide extent, underlying spatial patterns, or global trends in its past and future development. Moreover, even if GFC deforestation data processing using the Google Earth engine might enable this automation in the future, the visual approach will still be highly valuable for validating the robustness of automated approaches. Writing review & editing, Affiliation Competing interests: The authors have declared that no competing interests exist. On this basis, we can provide a preliminary overview of regional and national trends in the development of the extent of shifting cultivation over the past 40 to 50 years. Formal analysis, Livestock may be at risk, both directly from heat stress and indirectly from reduced quality of their food supply. [17] showed that these regions have experienced marked decreases in shifting cultivation. Venezuela [67]), and Madagascar [68]. The aforementioned map produced by Butler [13] (Fig 4) is a hand-drawn representation of areas where both shifting and non-shifting primitive subsistence agriculture exists, as Butler put it. Effects | Facts - Climate Change: Vital Signs of the Planet Updates? However, this future may also provide better opportunities for production and income generation if development efforts are sensitive to the needs of shifting cultivators [73,74]. We estimate that shifting cultivation landscapes currently cover roughly 280 million hectares worldwide, including both cultivated fields and fallows. Peninsular Malaysia, central and southern Thailand) [28]. 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. Impact of shifting cultivation on environment: an assessment on the Please refer to the appropriate style manual or other sources if you have any questions. We have nonetheless ventured to display our estimates in predictive maps because they are based on a spatially explicit analysis in 2010. For each grid cell, the occurrence of shifting cultivation declined linearly by the mid-point of the estimated losses in 2030, 2060 and 2090 (see Section 3.4). The Data behind Deforestation Causes of Deforestation The areas referred to as the rural complex may be used as a proxy for the presence of shifting cultivation. This is only the case if, in addition to a pattern of small-scale clearings in the GFC data, a spatio-temporal pattern of different stages of fallow and regrowth is visible in the very highresolution imagery from Bing and Google. Overall, a decrease after 2030 and disappearance after 2060 is expected. The increase of shifting cultivation in Myanmar shown in Fig 6 is due to a marked underestimation in the Butler map, which can possibly be explained by the limited availability of information about Myanmar after the military government came to power in 1962. The map is binary (presence-absence), with no information on occurrence frequency or land-use intensity. To approximate the current extent of shifting cultivation landscapes globally we used the results of a time-series analysis of mainly Landsat images characterizing forest extent and change [8], hereafter referred to as Global Forest Change (GFC) data set. In fact, they should be understood as best guesses about general patterns rather than temporally and spatially accurate predictions, as land use transitions often happen suddenly, causing abrupt changes over large areas [23]. Climate Change. Eutrophication is the process in which a water body becomes overly enriched with nutrients, leading to plentiful growth of simple plant life. Deforestation in the tropical rainforest - Internet Geography By contrast, we expect that shifting cultivation will persist for a longer time in Africa, especially in Central Africa. All answers were anonymous and cannot be traced back to the individual expert. Using the mean values of the ranges specified for the different occurrence classes for all cells in all classes results in a total area of 280 Mha. Yes Nearly two-thirds of its population depends directly on agriculture for its livelihood. Shifting cultivation - Wikipedia The remaining cells (3,887) were excluded from the analysis as shifting cultivation can be assumed to have never existed or disappeared decades ago (see Fig 5 and Method section). Simran IAS Academy on Instagram: "#Learnbymaps is here to explain you Areas drenched by irrigation can become waterlogged, creating soil conditions that poison plant roots through anaerobic decomposition. https://doi.org/10.1371/journal.pone.0184479, Editor: Benjamin Poulter, Montana State University Bozeman, UNITED STATES, Received: September 2, 2016; Accepted: August 24, 2017; Published: September 8, 2017. 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). This figure was elaborated by the first author using ArcGIS 10.4. https://doi.org/10.1371/journal.pone.0184479.g003. In order to assess both past and future land use transitions in areas currently under shifting cultivation, we identified experts with recent knowledge of these areas by searching the Web of Science (All Databases) for papers published between 2005 and 2015 whose title contained shifting cultivation or similar terms. Initially, we considered all 6,704 one-degree cells covering the land area between 30S and 30N, where shifting cultivation is likely to occur [17]. Environmental Impacts of Food Production - Our World in Data Madagascar has seen only slight decreases; especially along its eastern escarpment the area under shifting cultivation has remained stable over the last two decades (e.g. As global level ground data collection is not feasible and no global data on shifting cultivation for the considered time span of 2000 to 2014 is available, we generated a validation dataset, which contains a detailed delineation of the areas under shifting cultivation for a stratified sample of one-degree cells. India, Bangladesh), comparison of the maps (Fig 6) and the survey responses point to similar trends. Writing original draft, Roles Shifting cultivation is a rotational agriculture and forest management system practiced sequentially on the same plot of land. Our main objectives in this study are therefore 1) to review published knowledge about current status and past trends in the development of the global extent of shifting cultivation; 2) to assess the recent global distribution of shifting cultivation and, based on these trends and expert statements, 3) to provide a first estimation of the future extent and spatial distribution of shifting cultivation until 2090. Maps created in QGIS 2.16. https://doi.org/10.1371/journal.pone.0184479.g002. Extreme weather. In addition, we used available very highresolution satellite imagery from Bing and Google (most images dating from the period between 2008 and 2015; visited between September and April 2015) in an ArcGIS Desktop 10.4 and QGIS environment to examine visually whether a given area for which the GFC data indicated a spatio-temporal pattern of small-scale clearings consistent with shifting cultivation, was indeed likely to be under shifting cultivation. 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. - Myanmar: Shifting cultivation is estimated to mostly disappear sometime between 2060 and 2090 if conflicts between union government and ethnic armed groups are resolved. [10] compiled available published shifting cultivation area estimates for seven countries: Thailand, Laos, Cambodia, Vietnam, Myanmar, Malaysia, and Indonesia. Mining An increased demand for minerals is also driving the mining industry to destroy forests. No source is reported for the map, but most likely it builds on a number of regional studies that was carried out between the 1940s and the 1970s, as well as general knowledge of where shifting cultivation and other extensive smallholder farming systems were found. [1]. broad scope, and wide readership a perfect fit for your research every time. - Borneo and Sulawesi: Shifting cultivation is expected to disappear sometime between 2030 and 2060. The ranges are based on the expert survey and observed trends between the Butler map and our 2010 classification (Fig 5). Writing original draft, These changes are not fully reflected in the above comparison between the Butler map and our own spatial investigation for 2010 because in many areas they have resulted only in a reduced occurrence of shifting cultivation but not yet in its full disappearance. Environment; What you can do right now to advocate for the planet. Writing review & editing, Affiliation Shifting cultivation is the major occupation and the main source of income of the marginal farmers ( Jhumias) in Mizoram. However, it is important to underline that this assessment is based on very few survey responses (Fig 3) due to the small number of existing studies on shifting cultivation in Africa. 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). Yes The difference appears plausible if we consider that Spencers estimate is based on a hand-drawn map and that Asia has seen considerable decreases in shifting cultivation since that map was created (see section on recent trends below). Writing review & editing, Roles [43] when using the same source material for the classification as for the reference or validation data, it is essential to create the reference/validation data with a more accurate process than the classification. The land takes many years to replenish just at the cost of providing yield for 2 to 3 years. The global shift towards this model of farming in the last sixty years has come with many costs. PDF research article International Journal of Commerce and Business [1], possibly owing to the scale (1-km resolution) of the GLC2000 data sets. Given that biomass regrows very quickly in the humid tropics, the GFC data set treats large shares of a field cleared for shifting cultivation and kept fallow for a relatively short period as deforestation. Validation, Solution Shifting Cultivation: Slash-and-burn cultivation is another name for shifting cultivation. Its authors detected changes in what they call the rural complex for the period from 2000 to 2010. How Climate Change Will Affect Plants - State of the Planet [1]. Centre for Development and Environment, University of Bern, Bern, Switzerland, Roles Shifting cultivation, a resource-based subsistence farming, is no longer relevant because of the large population and its growing demands. It does so by following natural cycles, recycling nutrients and water, while omitting excessive use of agricultural chemicals. No, Is the Subject Area "Surveys" applicable to this article? northern Zambia and in the Democratic Republic of the Congo), parts of southeastern Africa (e.g. The area approximation of actual shifting cultivation landscapes was performed based on the average occurrence rates in the one-degree cells for each of the five classes above (>1% class: 0%; 19%: 5%; 1019%: 15%; 2039%: 30%; 40%:70%). Shifting cultivation (SC) is a traditional land-use system to ensure livelihood in the Amazon (Villa et al., 2020).The traditional SC have small areas (0.1-0.8 ha) and short cycles of agriculture (1-3 years) with high crop diversity followed by fallow periods of 2-7 years [Fig. Visual interpretation has well-known limitations in terms of subjectivity and potentially limited reproducibility [29], but there are two main reasons why a visual approach has been chosen: Firstly, while a number of approaches has recently been developed to detect shifting cultivation based on automated approaches at the regional and national level using remote sensing data (e.g. Shifting cultivation remains widespread, despite decreases in its extent over the last four to five decades. The Neolithic Revolutionfacts and information - National Geographic The results indicate that shifting cultivation is likely to persist longest in Africa. Many of the other decreases from Butlers to our map (dark brown in Fig 6) can also most likely be related to the actual disappearance of shifting cultivation in these areas that have seen significant land use transitions over the past 40 to 50 years. Soil is the foundation of most types of agriculture. In Asia, we expect that continued rapid economic development and the related changes in agricultural practices and, more importantly, in the economic structure (from the primary to the secondary and tertiary sectors) may cause shifting cultivation to disappear faster than in Africa or the Americas. 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. In Central America, shifting cultivation is still widespread, and both Fig 6 and the survey results indicate an increase in some areas (e.g. These negative effects can be identified in the form of localized deforestation, soil and nutrient loss, and invasion by weeds and other species. Climate change impacts on food production - The Ecologist This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Writing original draft, Also when considering the different levels of occurrence of shifting cultivation estimated based on the overall impression of the landscape per one-degree cell, the accuracies were high (see confusion matrix in Table 2), with an overall classification accuracy of 87.8%. Yes 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. Comparison of these figures with the GLC2000-based area estimate for Laos of almost 11 Mha [1] underlines the problem of using the GLC2000 to estimate areas under shifting cultivation. The producers and users accuracies were calculated for each occurrence class (< 1%; very low: 19%; low: 1019%; moderate: 2039%; high: 40%.) IWGIA - IWGIA - International Work Group for Indigenous Affairs Citation: Heinimann A, Mertz O, Frolking S, Egelund Christensen A, Hurni K, Sedano F, et al. This is reflected both in the comparison of the two spatial data sets (Fig 6) and in the survey responses. 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%). Forest and trees play an important role in balancing the environment. - Shifting cultivation also destroys the habitat of wild animals at large. In some specific areas, especially in Central Africa, it is likely to increase over the next decade before it begins to decline. The study by Silva et al. Climate change is a leading cause of deforestation. Of the remaining 225 authors, 72 responded and 49 provided usable information (see S1 File). These systems are naturally suited for harsh environments and fragile ecosystems of the tropics. - The primary disadvantage of shifting cultivation is cutting down of forest, which further leads to deforestation. the effect of shifting cultivation and what actually is shifting Hence, the occurrence level was estimated and not measured and the classification was based on a coarse assessment of the landscape (also see accuracy assessment below). Shifting Cultivation - an overview | ScienceDirect Topics In West and Central Africa, shifting cultivation is largely continuing and has even been expanding in certain areas.
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