Examining deforestation and agropasture dynamics along the Brazilian TransAmazon Highway using multitemporal Landsat imagery

• Published in: GIScience and remote sensing Vol. 56; no. 2; pp. 161 - 183
• Main Authors: Li, Guiying, Lu, Dengsheng, Moran, Emilio, Calvi, Miquéias Freitas, Dutra, Luciano Vieira, Batistella, Mateus
• Format: Journal Article
• Language: English
• Published: Taylor & Francis 17.02.2019; Taylor & Francis Group
• Subjects: agropasture expansion; deforestation; human-induced factors; multitemporal Landsat imagery; secondary forest; TransAmazon
• ISSN: 1548-1603; 1943-7226
• DOI: 10.1080/15481603.2018.1497438

This research aims to understand the difference of major land-cover change results caused in various time periods and to examine the impacts of human-induced factors on land-cover changes along the TransAmazon Highway region. The Landsat Thematic Mapper and Operational Land Imager data from 2011, 2014, and 2017 and our previous land-cover classification results in 1991, 2000, and 2008 were used to examine land-cover dynamics. A classification system consisting of five land-cover classes - primary forest (PF), secondary forest (SF), agropasture (AP), urban area, and water - were chosen. The hierarchical-based classification method was used to generate land-cover classification results, and the post-classification comparison approach was used to produce detailed "from-to" conversions for each detection period. The emphasis was on deforestation of PF, dynamic change of SF and AP, and urbanization over time. The impacts of human-induced factors such as population and economic conditions on urban expansion, AP expansion, and deforestation were examined. This research indicated that selection of a suitable time period was critical for effectively detecting land-cover changes; that is, too long time period (i.e., 9 years) cannot accurately capture some land-cover changes such as the AP and SF in this research. Although deforestation - the conversion from PF to SF and AP - accounted for a large proportion of land-cover changes, the changes between SF and AP became more important than PF conversion, and required a short time period (i.e., 3 years here) for effectively reflecting their dynamics. Human-induced factors play important roles in deforestation, dynamic changes between AP and SF, and urbanization.