The Atlantic Forest of South America: spatiotemporal dynamics of remaining vegetation and implications for conservation

Abstract

AbstractThe 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 1986-2020. We analyzed landscape metrics of forest vegetation only (FV), forest plus other natural vegetation (NV), and investigated the sensitivity of metrics to linear infrastructure. Currently, remnants comprise about 23% of FV and 36% of NV, and have decreased by 2.4% and 3.6% since 1986, respectively. Linear infrastructure negatively affected large fragments (>500,000 ha) by breaking them apart. Our findings suggest that AF protection legislation adopted in mid-2005 has taken effect: between 1986-2005, there was a loss of FV and NV (3% and 3.45%) and a decrease in the number of FV and NV fragments (8.6% and 8.3%). Between 2005-2020, there was a relative recovery of FV (1 Mha; 0.6%), slight loss of NV (0.25 Mha; 0.15%) and increase in the number of FV and NV fragments (12% and 9%). Still, 97% of the vegetation fragments are small (<50 ha), with an average fragment size between 16 and 26 ha. Furthermore, 50-60% of the vegetation is <90 m from its edges, and the isolation between fragments is high (250-830 m). Alarmingly, protected areas and indigenous territories cover only 10% of the AF and are very far from any fragments (>10 km). Our work highlights the importance of legislation and landscape dynamics analysis to help monitor and keep track of AF biodiversity conservation and restoration programs in the future.HighlightsThere is 23% forest and 36% natural vegetation cover remaining in the Atlantic Forest.Between 1986-2020, native forest cover decreased by 2.4% and natural vegetation by 3.6%.Since 2005, there has been a 1 Mha increase in forest area by small fragments (1 ha).Roads and railways reduced by 56%-89% fragment size, especially on large fragments.Alarmingly, 97% of fragments are small (<50 ha) and 60% are under edge effect (<90 m).