3.4.1. Keywords

The keywords show the essential topics of an article (Figure 4). From 502 keywords, the words with at least 10 mentions were historical ecology (32 mentions), Amazon (27 mentions), forest (24 mentions), archaeology (20 mentions), landscape (19 mentions), environmental (15 mentions), indigenous (15 mentions), conservation (14 mentions), dark-earth (12 mentions), Amazonian (11 mentions), Brazil (11 mentions), managemen<sup>t</sup> (10 mentions), and traditional (10 mentions). As Historical Ecology works with the relationship between people and the environment, numerous keywords refer to ethnosciences such as ethnoarchaeology [105], ethnobiology [106], ethnobotany [107], ethnoecology [84], ethnomusicology [15], ethnoprimatology [71], and ethnotaxonomy [84]. The suffix anthro also reveals this relationship as in Anthropocene [97], anthropogenic forests [108], anthrosols [109], anthropogenic landscapes [110], and ecological anthropology [111]. Other examples of this people-environment relationship are biocultural diversity [87], biopolitics [94], cultural ecology [111], domesticated forest [109], domesticated landscape [112], environmental history [113], environmental managemen<sup>t</sup> [114], environmental racism [68], human ecology [115], and local ecological knowledge [116]. There are also works about indigenous peoples and traditional populations, for instance, the Ka'apor [15,117], the Guajá [118], the Guarani [114], the Nadahup-Arawak-Tukano [119], the Marajoara [120,121], indigenous groups of the Middle Purus [122]; *quilombolas* [77,94,123,124], *beiradeiros* [125], and *caiçaras* [126] have also been included. There are also mentions to immigrant groups such as the Japanese [124] and the German [127].

**Figure 4.** Most found keywords in the systematic mapping.

*Quilombolas* are traditional Afro-descendant Brazilian people, formed by ex-enslaved people, enslaved who fled from captivity, and the ones that were born free. Their name derives from the places where they sought refuge, the *quilombos*. This ethnic group developed characteristic relationships with the environment surrounding them, amalgamating African knowledge with indigenous practices and some cultural traits from the Europeans.

*Beiradeiros* (also translated as forest peasants) or *ribeirinhos*, are considered a traditional group for the way they relate to the abundant rivers in the Amazon basin. With substantial indigenous influence, it also comprises European and African traits. The name given to those groups reflects how they live: at the river margins, relying on the seasonal oscillation of river water levels to obtain food through fishing, hunting, and short-cycle agriculture amongs<sup>t</sup> the forest.

*Caiçaras* are groups that make up the traditional Brazilian populations, formed by the syncretism between indigenous people, European descendants, and Africans (on a smaller scale). This ethnic group can be characterized by populations who remained isolated on the Atlantic Forest coast for many years, developing artisanal fishing and other unique relations with nature.

The keywords highlight the importance of the dark-earth studies in the Amazon [28,90,105,108,109,112,128–132] for Historical Ecology research in Brazil. The field of archaeology stands out. Some other interesting topics that appear only a few times in the keywords are: African influence [101,133], defaunation [134], fire [81,90], gender [127], geoglyphs [135], mining pollution [80], shamanism [122], among others.
