Roads in the Southwestern Amazon, State of Acre, between 2007 and 2019

Over the past 40 years, roads have been the main driver behind the State of Acre&rsquo

s occupation and development. However, the expansion of roads, has often been associated with the advance of deforestation, habitat fragmentation, and social conflicts. There are no up-to-date data available on the current extent of Acre&rsquo

s road network nor its environmental and socioenvironmental impacts. In this study, we updated the State of Acre&rsquo

s road network map for the period 2007 to 2019 through the visual interpretation of 153 Landsat images (5, 7, and 8) at a scale of 1:50,000. To estimate the impact of roads, we measured the distribution of roads in municipalities and in different land tenure categories and calculated the correlation between roads and annual deforestation. Up to 2019, we estimated 19,620 km of roads, of which 92% were unofficial roads, 6% federal roads, and 2% state roads. The roads increased at an average annual rate of 590 km year&minus

1. The most significant advance in road length between 2007 and 2019 was in protected areas (240%), followed by public lands (68%) and settlement projects (66%). We recommend monitoring of the road network to understand the landscape&rsquo

s evolution and support actions against illicit environmental and socioenvironmental impacts.