For several decades, research on the biodiversity of the neotropical South American environments, whether it is dense evergreen forest, wetlands, inselbergs or savannas, has taken into account the influence of ancient human occupation. While some research teams do not take account of historical evidence as explanatory data, some research teams go so far as to qualify certain environments such as savannahs as bio-cultural constructions (Stier et alii, 2020), others explain the hyperabundance of certain tree species in the Amazon rainforest such as Hevea brasiliensis by the cultivation of this latex tree during the period of the rubber boom (Le Tourneau, 2019). Research on the biodiversity of equatorial environments as well as rapid assessment programs suspect the influence of ancient human activities (De Dijn et alii, 2005 ). On closer inspection, however, we see that the role of these influences is more often postulated than demonstrated and measured by quantitative geohistoric reconstructions based on historical sources (Haripersaud, 2009). Sometimes, historical sources dating from the sixteenth or eighteenth century are invoked as raw data without prior historical analysis to support the theses of the researchers. From a few cases of different environments (evergreen forest, wetlands, savannas, inselbergs), we seek to show what historical geography can bring to the evaluation of the state of current ecosystems and of the state of conservation of certain species and that it should be more seriously taken into account to determin conservation policies.