During an archaeological survey in Roraima State, Brazil, in July 2019, I was mistaken as a Macuxi, an indigenous person, by a landowner, whom quickly expelled me from his property. In my country, landowners often assume indigenous persons enter their property to reclaim the land. It wasn’t until the archaeological coordinator explained I wasn’t an indigenous person in disguise that I was allowed back onto his property. The landowner then proceeded to offer me mangos, oranges, and macaxeira as an apology for his mistake. His use of fruits to make amends for treating me poorly is a common gesture among traditional communities in Amazonia, where the circulation of plants flows with the social interplays of everyday life. A visit to a relative, neighbour or friend is an opportunity for the exchange of fruits, seeds, condiments, medicines, seedlings, and ornamental plants. I’ve witnessed and participated in this botanical exchange from an early age, growing up in a small village on the bank of the Guamá River in Pará State, Brazil.
For as long as I can remember, the matas (forests) has been part of my life. As a child, I could find my way through the igapó (flooded forests), the capoeiras (early secondary forests) and the tapera (mature secondary forest) occurring on my family’s land. Making a perfect picture of a cultural forest, the tapera behind my grannie’s house had abiu, genipapo, uxi, cupuaçú, castanha-do-Pará, ingá, mari, bacuri, biribá, taperebá, pitomba, andiroba, copaiba, and jatobá, (all fruit trees). I paid no attention to the ruins of old houses and knew by heart where the patch of diverse and delicious fruits was in the middle of the ‘dense forest’. Back then I would have been a great interviewee for an ethnobotanist. As my curiosity about the plants shifted from the household realm to a scientific one, I discovered a deeper vegetation history and their potential to inform about past human-environment interactions.
Although the scale is still a matter of debate, the impact left by pre-Columbian societies in Amazonian environment is now accepted by many scientists and specialists across various disciplines. An increasing body of evidence shows that past human activities left lasting inter-generational changes in the landscapes surrounding archaeological sites throughout the Amazon, such as vegetation structure and composition as well as anthropogenic soils. Commonly known as terras pretas de índio, the highly fertile Amazonian Dark Earths (ADEs) are soils transformed by daily settlement activities and figures as a major human footprint in Amazonian landscapes together with cultural forests. The practices associated with the formation of ADEs are as diverse as the number of sites containing ADEs across Amazonia. These anthrosols, any soils that have been profoundly modified by human activities, vary in distribution, density of material culture, and soil properties (i.e. varying degrees of anthropization, the conversion of the landscape by human action).
From an archaeobotanical approach, I investigated the plant management associated with ADE formation in the Lower Tapajós River, one of the largest clear water rivers in Brazil. Studying this area helped me to understand the legacies left by ancient people on the ground. The entire Lower Amazon region, including the Lower Tapajós River, has a long history with humans, beginning around 12,000 years ago at the Caverna da Pedra Pintada, including an early ceramic production from 7,000 years ago at Taperinha, and the densely populated and regionally organized Tapajó society from 1,000 to 350 years ago. Producers of a highly distinct pottery, the Tapajó dispersed across the region, which is interpreted as evidence for a deep knowledge of the environment and combined exploitation of forest and aquatic resources.
I studied three archaeological sites from the Tapajó culture by analysing micro charcoal, soil geochemistry and plant remains in the soil – phytoliths (opaline silica bodies formed within and between plant cells). Integrating these multiple lines of evidence, I was able to document varying degrees of vegetation changes and an increase in soil fertility in the three studied sites intrinsic to local land uses. In domestic contexts such as house floors, hearths and refuse pits, the phytolith assemblages represented domesticated plants and native wild ones, consisting of evidences of plant use within these past settlements. For example, phytoliths from açaí palm, manioc, maize, and squash in assemblages from these domestic areas documents their use and discard. In addition, the plant remains recovered from the areas surrounding house structures exhibited an anthropic vegetation composed of edible forest plants (açaí, tucuma/peach palm, huckleberry and soursop) and crops such as maize, squash and manioc.
When a patch of forest is cleared, a set of pioneer plants thrive in the open area. These are considered disturbance indicators. In my case studies, high proportions of forest taxa in contrast with low frequencies of disturbance indicators revealed a predominantly closed vegetation cover with minor changes on the sites during the Tapajó occupation. However, the micro charcoal remaining from fire activities registered sharp increases inside the sites, which indicated that localized burnings were occurring, since it did not clear the forest. Therefore, these vestiges showed that the Tapajó used in-field burning, a technique of soil amelioration ethnographically observed in Amazonia.
Altogether, these data suggested that soil enrichment was explored for food production that consisted of polyculture practices in an agroforestry system. Polyculture is characterized by the practice of growing two or more crops in the same area, common in small-scale agroforestry systems and is a sustainable way to maximize nutrients uptake and balance the soil fertility as well as suppresses weed and control pests. When the phytolith terrestrial record from one of the sites was combined with pollen data from a lake sediment near the site, the results suggested a long-term polyculture agroforestry system beginning ~ 4,500 years ago and increasing after the formation of ADEs, ~ 2,000 years ago. These data represented the first concrete evidence of multiple crop cultivation and gradual enrichment of edible forest species for eastern Amazonia.
The regional emergence of the Tapajó in tandem with ADE formation involved an intensification of a subsistence strategy previously practiced, including a soil enrichment technique. In other words, the Tapajó applied a traditional ecological knowledge to expand regionally, with the simultaneous benefits of enriching the soil and the vegetation composition by favoring some fruit tree species. Whereas the standing vegetation surrounding the studied sites is a living heritage of this resilient history of food production, the sediments are also legacies of that history and proven to be a reliable source of information about past land use and subsistence strategies. In the current scenario of increasing burning of Amazon forests, we’re losing the biodiversity of cultural forests, yet another harmful outcome from conservative neo-liberal policies. In face of this situation, archaeobotanical studies are promising to help us not only understand the past, but also to address the contemporary issues regarding vegetation.
The diversity of the human experience as well as the interactions with the environment can be seen in the archaeological records across Amazonia. My research demonstrated that plants are an essential part to understanding ancient transformations of the environment as well as addressing enduring past livelihoods and their legacy in current forest compositions. Additionally, as a Brazilian researcher I am constantly aware of the historic and continuing process of alienating indigenous groups from their territories, enslaving and associating them to a persistent and ever thriving bad reputation. As an Amazonian, I know even though the indigenous ancestry is present in the daily life of caboclo (a person of mixed Indigenous Brazilian and European ancestry) communities, be that the vocabulary, foods, general knowledge of the environment or the landscapes they created such as the taperas, the power of colonization is so strong that their heritage is systematically denied. Often resulting in conflicts between caboclos and indigenous folks, as illustrated by the landowner’s attitude towards me.
Plant-people interactions and how it influences Amazonian identities and territoriality, as well as the legacies of ancient societies in the vegetation fascinates me. Ethnobotanical research and my own experience reveal that the ecological knowledge is entangled with social dynamics, community identities and territoriality. My next challenge is to investigate the role these anthropic signatures in the forest played in the territorialisation of ancient societies along the Amazon basin. For me Amazonia is both a familiar place and an enigma to solve.