Human intervention near archaeological sites in Brazil is on the rise

In an unprecedented initiative, a project by MapBiomas entitled “Land Cover and Land Use in Archaeological Sites in Brazil (1985–2023)” gathered information georeferenced by Brazil’s National Historical and Artistic Heritage Institute (IPHAN) and made it public. In all, 27,974 sites have been mapped where the remnants of the people that inhabited the Brazilian territory at other times can be found. The data available enable comparisons of images from 1985 to 2023.

“Cross-referencing and making these data available to the public helps us understand where these sites are located and whether it’s in an area impacted by human activities. It can also cast light on the expansion of anthropogenic activities in a given region, which can serve as a warning,” Thiago Berlanga Trindade, head of IPHAN’s Data Registration and Record Service said.

Aerial view of the Morumbi archaeological site in São Paulo – Letícia Correa/ Zanettini Arqueologia

After analyzing the data, Mapbiomas researchers found a reversal in land coverage and land use within 100 meters of archaeological sites in recent decades. By 2023, over half of these will be near recent human interventions, which makes preservation challenging.

As it stands today, almost half of these sites, 49.6 percent, are located in deforested areas marked by human presence—such as grazing, agriculture, and urban areas. In 1985, this percentage was no more than 41.5 percent, and most of it—53.5 percent—was in areas of native vegetation, such as forests, savannas, and natural grasslands.

Forty years ago, forests were predominant around these historic sites. They accounted for 43.2 percent of the surrounding area. In 2023, farming occupied the largest share—43.1 percent of land use around archaeological sites.

According to MapBiomas’ Scientific Coordinator Julia Shimbo, it was often human activity itself that revealed the presence of these archaeological sites, identified through research, infrastructure works, or deforestation.

“Despite the historical occupation of these sites, we can now look at the changes and impacts of recent occupation on these areas,” she argued.

Biomes

In absolute numbers, the Amazon is the biome with the largest number of archaeological sites recorded—10,197, more than a third of Brazil’s total. The caatinga has 7,004 sites with traces of human presence in other eras, while the cerrado and the Atlantic forest also stand out, with 4,914 and 4,832 respectively. The pampa and the pantanal have 904 and 123, respectively.

When the experts examined human activities around archaeological sites in each Brazilian biome, they found that the Atlantic forest recorded the highest proportion of sites in anthropogenic areas—63 percent. In the Amazon, 47.5 percent were already in areas of human disturbance in 2023, compared to only 19 percent in 1985.

“When an archaeological site is located in an anthropized area, a series of concerns about its preservation and conservation must be observed. This survey can point to the places where we should pay more attention, or treat it as a priority,” Berlanga pointed out.

In absolute numbers, the Amazon is the biome with the largest number of archaeological sites recorded—10,197, more than a third of Brazil’s total – Rafa Neddermeyer/Agência Brasil

Deforestation

Deforestation alerts were also applied to data for 2019–2024. In this assessment, 122 archaeological sites were found in areas with deforestation alerts issued during this time range. Of this total, the majority were in the caatinga (29), Atlantic forest (31), and Amazon (17) biomes.

In the view of Marcos Rosa, technical coordinator of MapBiomas, cross-referencing these data can help stop recent human occupation from causing damage to the history contained in these spaces. He explained that, based on these data, one can ascertain that “almost two thirds of [archaeological sites, 79,] are in areas cleared for the expansion of farming. In Rio Grande do Norte state, 13 of the 19 archaeological sites are under deforestation alerts resulting from the expansion of sustainable energy projects [solar or wind energy],” he noted.

In view of the results, Federal University of Santa Catarina Professor Marina Hirota, who also collaborated on the study, warns, “the growth of anthropogenic activities around the sites reinforces the importance of conservation and management policies for Brazil’s archaeological heritage, especially in the face of growing pressure on biomes.”