The Atlantic Forest of South America: Spatiotemporal dynamics of the vegetation and implications for conservation

The Atlantic Forest in South America (AF) is one of the world's most diverse and threatened biodiversity hotspots. We present a comprehensive spatiotemporal analysis of 34 years of AF landscape change between 1986 and 2020. We analyzed landscape metrics of forest vegetation only (FV), forest plus other natural vegetation (NV), and the sensitivity of metrics to linear infrastructure. Currently, the AF remnants comprise 22.9% of FV and 36.3% of NV, an extent that has decreased by 2.4% and 3.6% since 1986, respectively. Linear infrastructure affected mainly the largest fragments (>500,000 ha), reducing their size by 56%-94%. The period before 2005 was characterized by loss of FV and NV (3% and 3.43%) and decrease in the number of FV and NV fragments (8.6% and 8.1%). In contrast, after 2005 the vegetation stabilized, with a recovery of 1 Mha of FV (0.6%) and an increase in the number of fragments, due in part to environmental policies. However, the AF is still a highly fragmented domain: 97% of the vegetation fragments are small (<50 ha), with an average fragment size between 16.3 and 25.5 ha; 50-60% of the vegetation is <90 m from its edges, and the isolation between fragments is high (250-830 m). Protected areas and indigenous territories cover only 10% of the AF vegetation, and most vegetation lies are >10 km in these areas. Our work highlights the importance of legislation and analysis of landscape dynamics to help future conservation and restoration programs for biodiversity in the Atlantic Forest.