Formal analysis, Predicting future trends in the development of any form of land use requires extreme caution [23,69]. It coincided with the end of the last ice age and the beginning of the. Centre for Development and Environment, University of Bern, Bern, Switzerland, Roles Methodology, Shifting cultivation in general, is a system of farming in which fields are prepared by cutting down the natural vegetations. Laos, Vietnam) over the past 15 to 25 years is not reflected in this comparison. After being used to grow a variety of crops for a year or two, the area is allowed to lie fallow for a period of rejuvenation, while the farmer moves on to a . Writing review & editing, Affiliation But information about such landscapes is urgently needed to improve the . With these caveats in mind, we aggregated responses to the national scale and to three supranational regions: the tropical parts of 1) Central and South America, 2) Africa, and 3) Asia. Shifting cultivation causes a high national waste as it converts the green land into a barren land. Writing review & editing. Methodology, 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. 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. Yes Furthermore, it should be noted that the large difference between the two spatial data sets (Fig 6) in arid and semiarid parts of Africa (Sahelian and Sudanian zones of northern Africa as well as parts of southern Africa) is partly due to the fact that Butler included other, non-shifting smallholder farming systems in his map. Writing original draft, 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). Nearly two-thirds of its population depends directly on agriculture for its livelihood. The classic studies on shifting cultivation in Africa [4648] do not provide any area data for the continent, and for Central and South America we were unable to find any regional-scale past area estimation. To assess published scientific material on the current extent of shifting cultivation, we searched the Web of Science (All Databases) using the following search string: [Title]: "shifting cultivation" or swidden* or "slash and burn" or "slash-and-burn" or "shifting agriculture" AND [Year published]: 20052016. But developing predictions is essential to estimating future land usebased greenhouse gas emissions, and we consider that our approach will help to improve existing projections, which essentially assume the area under shifting cultivation to remain constant in the future [2]. The author has visited the entire Mizoram state and observed that shifting cultivation has a severe adverse impact on the environment, forest depletion and landscape degradation. Visualization, The areas referred to as the rural complex may be used as a proxy for the presence of shifting cultivation. The spatio-temporal pattern of the annual deforestation data from 2000 to 2014 at a resolution of 30 meters provides the basis for our approximation. It is a sustainable method of farming in the rainforest. The results indicate that shifting cultivation is likely to persist longest in Africa. Fig 5 presents the results of our own visual approximation of the global extent of shifting cultivation around 2010 at a one-degree resolution, based on Hansen et al.s (2013) GFC data and very highresolution satellite imagery. Forest and trees play an important role in balancing the environment. For this reason, we have estimated future changes in shifting cultivation by combining observed trends between the Butler map and our own map with experts survey responses regarding future changes in shifting cultivation in different parts of the world. [24], who in turn had cited Dixon et al. Half of the world's habitable land is used for agriculture. This figure was elaborated by the first author using ArcGIS 10.4. https://doi.org/10.1371/journal.pone.0184479.g003. Centre for Development and Environment, University of Bern, Bern, Switzerland, Roles 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]. https://doi.org/10.1371/journal.pone.0184479.s001. One of the most obvious consequences is the depletion of aquifers, river systems, and downstream ground water. Shifting cultivation is an agricultural system in which plots of land are cultivated temporarily, then abandoned while post-disturbance fallow vegetation is allowed to freely grow while the cultivator moves on to another plot. Moderate warming and more carbon dioxide in the atmosphere may help some plants to grow faster. Any change in the climate of an area can affect the plants and animals living there, as well as the makeup of the entire ecosystem. Our review of the more recent literature revealed surprisingly few studies containing regional or global estimates of areas under shifting cultivation. From droughts and wildfires to pests and pathogens, climate change is wreaking havoc on the world's forests. The downed vegetation, or "slash", is then left to dry, usually right before the rainiest part of the year.Then, the biomass is burned, resulting in a nutrient-rich . Formal analysis, We compared this result to Butlers (1980) binary (presence or absence) map of shifting cultivation, gridded into one-degree cells. broad scope, and wide readership a perfect fit for your research every time. 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. Writing review & editing, Roles 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. Of the remaining 225 authors, 72 responded and 49 provided usable information (see S1 File). 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. Cultivation (the preparation of land for planting crops) on the plot is done for a few years until the fertility of the formerly burned land is reduced. Fig 1A shows a one-degree square of northern Laos. Climate change is a leading cause of deforestation. In the absence of further data to validate past estimations of the extent of shifting cultivation, the Butler map may be considered a reasonable representation of the global distribution of shifting cultivation from 1960 into the 1970s. Furthermore we wish to express our gratitude to the two reviewers as well as the editor for the very useful comments and inputs. But soil health is negatively impacted by industrial agriculture practices like monocropping, synthetic fertilizers, pesticides and more. Yes Meanwhile, the area under shifting cultivation has decreased by 71.22% from 1997 and forest cover has decreased by 4.41% during the period. Extreme weather events like wildfires (which are responsible for an estimated 10% of degradation annually), droughts, and storm surges destroy millions of hectares of forest every year and their intensity is only increasing with global warming. 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. Concludes by addressing the need to protect and conserve the natural forests and wild life. Writing original draft, [17] showed that these regions have experienced marked decreases in shifting cultivation. Institute of Geography, University of Bern, Bern, Switzerland, Large forest or vegetation areas are cleared and burned down for mining operations. Both conditions apply to considerable parts of Central Africa. One land-clearing system of shifting agriculture is the slash-and-burn method, which leaves only stumps and large trees in the field after the standing vegetation has been cut down and burned, its ashes enriching the soil. 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. Writing original draft, Yucatan Peninsula [66], northern South America (e.g. In this specific case 1088 or 10.88% of the 1/100 degree cells within the one-degree sample cell were detected as having shifting cultivation in the validation data sets. In addition to searching the Web of Science, we also consulted three major book publications that could be assumed to contain relevant information [2426]. The search was performed in September 2015 and generated 316 results. 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%). Cultivation (tillage) is a practice that has been introduced to Australia from Europe by our farming pioneers. 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. decadal), the areas newly classified as having shifting cultivation (blue in Fig 6) should be added to the original Butler map, thereby producing an updated estimated extent of shifting cultivation for this earlier period. 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. No, Is the Subject Area "Earth systems" applicable to this article? Based on visual inspection of annual global deforestation data [8] from 2000 to 2014 and very high-resolution satellite imagery. A plot of land is cleared by cutting the trees and burning them. 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. In Mexico, however, the trend has been towards decreasing areas under shifting cultivation. Writing review & editing, Affiliations At the same time, shifting cultivation was one of the most sensitive variables in their model runs (along with wood harvesting). Yes After eliminating papers that were not related to recent shifting cultivation in the tropics (e.g. This study combines existing global Landsat-based deforestation data covering the years 2000 to 2014 with very high-resolution satellite imagery to visually detect the specific spatio-temporal pattern of shifting cultivation at a one-degree cell resolution worldwide. All answers were anonymous and cannot be traced back to the individual expert. Such areas are found in parts of Southeast Asia (e.g. (Fig 2A): the global distribution of the stratified sample of the 328 one-degree cells used in the validation data set. We have nonetheless ventured to display our estimates in predictive maps because they are based on a spatially explicit analysis in 2010. This has led to a paucity of global information on certain land use systems, including shifting cultivation at the global level. Shifting cultivation is the major occupation and the main source of income of the marginal farmers ( Jhumias) in Mizoram. It ensures the forest will recover. The principle of cultivation is to turn the soil into a fine tilth to provide the ideal environment for seeds to germinate. Visualization, For example, the large areas of tree plantations established in Vietnam and southern China in the 1980s and 1990s can also leave a mosaic signature at a certain point in time and might therefore be incorrectly interpreted as shifting cultivation (Fig 1). Department of Geographical Sciences, University of Maryland, College Park, United States of America, Roles Shifting agriculture has frequently been attacked in principle because it degrades the fertility of forestlands of tropical regions. It upsets the ecological balance as it disturbs many eco-systems of that region due to destruction of natural vegetation. Let us know if you have suggestions to improve this article (requires login). The uptick in mosquito-borne diseases, for example, or the rapid spread of roya, an insidious plant disease that threatens our supply of coffee are all indirect consequences of deforestation and global warming. [3037]) would be insufficient, as they only cover very few of our one-degree cells and are not representative globally. Mosaic landscapes under shifting cultivation, with their dynamic mix of managed and natural land covers, often fall through the cracks in remote sensing-based land cover and land use classifications, as these are unable to adequately capture such landscapes' dynamic nature and complex spectral and spatial signatures. Investigation, Extreme weather. Logging Updates? The search was performed in January 2016 and generated 324 articles, which we then screened for data on numbers or estimates of global or national areas influenced by shifting cultivation. Shifting cultivation, a resource-based subsistence farming, is no longer relevant because of the large population and its growing demands. It received 1 point in Formal analysis, 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. It is a system of rotating cultivation on a plot of land for 2-3 years and leaves it fallow for another 10-15 years. The red hatching in (B) indicates the 1/100 degree cells that were classified as having shifting cultivation. No, Is the Subject Area "Asia" applicable to this article? Climate change has caused increased heat, drought, and insect outbreaks. Shining cultivation fields are generally used not more than two years at a lime, after which . The analysis presented is primarily qualitative with a supplementary quantitative analysis of the causes of forest . The main outcomes presented in this study are maps showing the estimated presence of shifting cultivation at a one-degree resolution for the present, as well as, for the first time, estimations for 2030, 2060, and 2090.