Agricultural Expansion and Landscape Heterogeneity Explain Vegetation Degradation in Brazilian Atlantic Forest Landscapes

ABSTRACT Several anthropogenic activities in tropical forests, including deforestation and fragmentation, have led to intensive forest degradation. In fact, forest edges adjacent to anthropogenic land‐uses can be more exposed to abiotic changes and consequently lead to vegetation deterioration in forest interiors. However, there is still a lack of information on how temporal changes in land use can impact the vegetation degradation of tropical forests. Here, we investigate the influence of landscape context in explaining patterns of forest vegetation degradation over 35 years in two regions exhibiting different deforestation patterns in the threatened Atlantic Forest. Using the Normalized Difference Moisture Index (NDMI) and the Enhanced Vegetation Index (EVI), we assessed forest degradation in the center of 50 forest remnants. In particular, we estimated these indices and landscape metrics in a time series from 1985 to 2020, at a 5‐year interval, based on MapBiomas land‐use classification and Landsat imagery. Then, we used generalized linear mixed models to assess the influence of landscape metrics over time on NDMI and EVI. Our results indicated that forest degradation was intensified according to the increase in agricultural cover, although sites inserted in more heterogeneous landscapes showed reduced degradation (i.e., an increase in NDMI and EVI). We also observed that forest remnants surrounded by greater agricultural cover showed a decline in NDMI, especially in the initial years of the time series. We therefore emphasize the importance of curbing the agricultural expansion to reduce the long‐term forest degradation in Atlantic Forest remnants and suggest long‐term monitoring of forest quality using vegetation spectral indices.