A global view of shifting cultivation: Recent, current, and future extent

Andreas Heinimann; Ole Mertz; Steve Frolking; Andreas Egelund Christensen; Kaspar Hurni; Fernando Sedano; Louise Parsons Chini; Ritvik Sahajpal; Matthew Hansen; George Hurtt

doi:10.1371/journal.pone.0184479

A global view of shifting cultivation: Recent, current, and future extent

PLoS One. 2017 Sep 8;12(9):e0184479. doi: 10.1371/journal.pone.0184479. eCollection 2017.

Authors

Affiliations

¹ Institute of Geography, University of Bern, Bern, Switzerland.
² Centre for Development and Environment, University of Bern, Bern, Switzerland.
³ Department of Geosciences and Natural Resource Management, University of Copenhagen, Copenhagen K, Denmark.
⁴ Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, United States of America.
⁵ Department of Geographical Sciences, University of Maryland, College Park, United States of America.

Abstract

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. But information about such landscapes is urgently needed to improve the outcomes of global earth system modelling and large-scale carbon and greenhouse gas accounting. 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. The accuracy levels of our classification were high with an overall accuracy above 87%. We estimate the current global extent of shifting cultivation and compare it to other current global mapping endeavors as well as results of literature searches. Based on an expert survey, we make a first attempt at estimating past trends as well as possible future trends in the global distribution of shifting cultivation until the end of the 21st century. With 62% of the investigated one-degree cells in the humid and sub-humid tropics currently showing signs of shifting cultivation-the 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. We estimate that shifting cultivation landscapes currently cover roughly 280 million hectares worldwide, including both cultivated fields and fallows. While only an approximation, this estimate is clearly smaller than the areas mentioned in the literature which range up to 1,000 million hectares. 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.

Publication types

Meta-Analysis

MeSH terms

Conservation of Natural Resources* / trends
Datasets as Topic
Environment*
Geography
Reproducibility of Results
Satellite Imagery
Spatio-Temporal Analysis

Grants and funding

This research was supported by the Institute of Geography and the Centre for Development and Environment (CDE), University of Bern, Switzerland, as well as the Swiss Programme for Research on Global Issues for Development (r4d) supported by the Swiss National Science Foundation (SNSF) and the Swiss Agency for Development and Cooperation (SDC), grant number 400440 152167, the U.S. Dept. of Energy, grant number DE-SC0012972, and the Global Land Project Grant from the University of Copenhagen.