The influence of Guarani plant exchange networks on Atlantic Forest composition
In the Guarani cosmology, the natural world is closely connected with the supernatural world, which often occupies the same spaces (27, 50). Within this cosmology, the maintenance of botanical knowledge with therapeutic functions is also important (51), as well as the exchanges among villages. As we hypothesized, the connections between the villages through family and kinship ties facilitate plant exchange networks across the Guarani traditional territory. Our results reveal a small snapshot of the current panorama of the networks that connect the Guarani villages and the exchanges of plants that are still taking place in the Atlantic Forest biome, with emphasis on native species. A caveat of our study is that this snapshot is also limited by our small sample of villages and interviewees in each village, which were guided by Guarani’s availability and by their own indications of who we should interview.
In the exchange network, Tekoá Nhuu Porã (Campo Molhado), Tekoá Yyn Moroti Vherá (Mbiguaçu) and Tekoá Jatai’ty (Cantagalo) stand out with more citations and connections with the other villages mentioned (Figs. 1 and 2). These villages are located closer to the coast, and the plant exchanges revealed links with villages that are in the west part of Rio Grande so Sul and Santa Catarina States, as well as with the region of Misiones, in Argentina, more than 900 km from the Atlantic coast. In those areas, the Alto Uruguai Deciduous Seasonal Forest formations predominate, and the Indigenous Lands keep valuable forest fragments amidst monocultures. In Argentina, there are greater extensions of forest cover. One of these areas is the Yabotí Biosphere Reserve (52), a region identified by the Guarani as a place of reference to find certain floristic elements. Exchanges between these western villages and the Atlantic coast were already observed (27), with the transportation of propagules such as Chrysophyllum gonocarpum, Luehea divaricata, Parapiptadaenia rigida, Holocalyx balansae, and Petiveria alliaceae to the village of Mbiguaçu.
Almost half of the plants exchanged were trees, followed by herbs. Heineberg and Hanazaki (35) observed similar results among the Laklãnõ-Xokleng (from Jê linguistic group), reinforcing the importance of knowledge about forest tree species of indigenous peoples. In the present study, these plants associated with exchanges have the potential to be incorporated in environments and phytophysionogmies different than those of the place of origin.
For example, among the Myrtaceae family – one of the most important in the Atlantic Forest, with several edible fruit species (28) – Plinia rivularis was mentioned as an exchanged plant. It was brought from a place with Deciduous Seasonal Forest of upper Uruguay to Flor do Campo village, where the phytophysiognomy is of Semideciduous Forest. The origin of the individual of Plinia peruviana mentioned in Cantagalo is unknown since it was cultivated by a former resident. According to Sobral et al. (53), this species is characteristic of the Seasonal Semideciduous Forest and Mixed Ombrophylous Forest, which are forest formations different from the forest at Cantagalo. The dominance of this family in the Atlantic Forest may be related to the management carried out by indigenous peoples in the past, including, for example, enriched areas with Myrtaceae fruit trees in the South region found between the 19th and 20th centuries (28).
Several exchanged plants are related to religious beliefs. Keller, Prance, Tressens, Duarte (51), citing Cadogan (12), highlighted the complexity of Mbyá Guarani medicine plants related to religious beliefs. Seven exchanged plants were in this category. Among them, Tabernaemontana catharinensis stands out for its importance in the spiritual context. In the two villages of Rio Grande do Sul state, the seedlings of this species were brought from a village at São Miguel das Missões, Tekoá Koendju. The occurrence of this species is attributed to the whole Atlantic forest region (53, 54), but for the interviewees, it is rare, and the individuals present in the studied villages come from the exchanges. In M'Biguaçu, all individuals of T. catharinensis were planted, brought in the 1980s, but of unknown origin.
Yerba mate, or ka'a, Ilex paraguariensis, is a species exchanged with cultural and medicinal value for Guarani (55, 56). A variety of yerba mate with a lighter shade on the leaves were brought from Misiones to Campo Molhado indigenous land, and it is different from the one already found there, showing the potential of exchanges to increase the local variability of the species. Individuals of this species are also present in Morro dos Cavalos indigenous land, at Ombrophyllous Dense forest, which is not the attributed distribution for this species (usually occurring above 400 m of altitude (57)). This is another example of the transport of plants of cultural value to phytophysiognomies other than those of original occurrence. The historical relationship of yerba mate with indigenous peoples is not restricted to the Guarani: the species was also consumed among peoples of the Chaco and the Andes, where it does not occur spontaneously (56). The name “mate” is even derived from the Quechua word “mati”, which means the gourd or porongo where the drink is traditionally consumed. This leads us to an interethnic network of relationships in which people probably exchanged and cultivated the plant (56). Oliveira and Esselin (56), based on Posey (58), fit the plant in the category of semidomesticated because they are intentionally managed. If this management had not already taken place by the natives, it would have been more difficult to expand the herbs for economic exploitation, as occurred in the 19th century (56).
Another highly esteemed species is Cedrela fissilis, yary, which is considered a medicine of sacred value (1, 16, 51). It is a well-distributed species in South America and is one of the most threatened tree species, with a vulnerable status (54) due to the selective cutting and suppression of the Atlantic Forest. Given its cultural importance, it is likely that the Guarani historically contributed to the dispersion of this species through their exchanges.
Petiveria alliacea is another example of the Guarani influence on species composition in the southern Atlantic Forest. At Cantagalo, it was brought from the nearby village of Lami. Galante (1), Keller, Prance, Tressens, Duarte (51) and Bueno et al. (59) mentioned the traditional use of the species by the Mbyá-Guarani of Misiones (Argentina), the Kaiowá and Guarani of Mato Grosso do Sul, and the Guarani of São Paulo, respectively. This plant is also used by other indigenous groups, such as the Ka’apor of Maranhão, also from the Tupi group (60). The origin of this species is probably the Amazon rainforest (57).
Solanum mauritianum and Urera baccifera have a wide distribution both in the Atlantic Forest and in other Brazilian biomes, respectively (54). Both species were brought from the deciduous to semideciduous forest at Cantagalo and are mentioned in other studies with the Guarani (1, 16, 27), showing once again that the Guarani exchanges may have contributed historically to the composition of different phytophysiognomies.
Some species are naturally occurring in the phytophysiognomies of indigenous lands; however, they can be locally rare or absent. For example, Philodendron bipinnatifidum is one of the plants that are named at Opy, so that their ja (owner) authorizes their use (1). It is native to all forest formations in southeastern Brazil (57). However, in Morro dos Cavalos, there was only one known individual, a fact that also motivated the exchanges. The whip horse, Luehea divaricata, is another important species in Guarani medicine (27). The species is present in the cerrado and in all formations of the Atlantic forest (53). Despite this, in Campo Molhado, it was reported as not available spontaneously, which motivated the exchange. Oliveira (27) reported the absence of the plant in Mbiguaçu and the request of people from this village to purchase seedlings for planting.
Guarani exchanges can also contribute to the distribution of non-native plants. Three species exchanged were probably introduced in Brazil in the colonial period (57). These plants were also recorded in studies by Oliveira (27) for Plectranthus barbatus among the Guarani of Mbiguaçu, Noelli (18) for Matricaria chamomilla and Cossio (16) for Cajanus indicus.
Additionally, the exchanges of parts of plants with no propagative potential, such as for Inga virescens taken from Campo Molhado to a village in the Pampa biome, reflect the distribution of knowledge and the broad spectrum that the relationship Guarani-plants reach. This species is related to altitude forests, being better distributed in the Mixed Rain Forest (61) and absent in Pampa.
Oliveira (27) discussed possible migratory routes that contributed to the transport of species of flora from seasonal forests from the interior of the South American continent to the Atlantic coast. Klein (62) elaborated a list with species that would be characteristic of these routes, some of them mentioned in our study: Para paray - Jacaranda micrantha, Yxonguy - Luehea divaricata and Pipi - Petiveria aliacea (27). According to Reitz and Klein (63), factors such as climatic fluctuations could have favored seasonal forests so that certain species could reach the Atlantic coast, but Oliveira (27) states that the routes proposed by Klein overlap with the archeological sites of Guarani presence in southern Brazil, where many villages are also present today (27).
Guarani family, extended family
We found that more than half of the plant exchanges occurred between villages whose interviewees had close relatives, but there were also exchanges between villages with no close kinship ties. The caveat here is that our categorization of kinship relations oversimplifies the Guarani concept of extended family. The concept of extended family is “the most widespread sociological model” in Amerindian social organizations (22, 64). For Guarani, this organization is composed of several nuclear families (women and men who live together and their children) united by kinship and affinity relationships. Thus, an extended Guarani family can be made up of the wife (or a group of sisters) and her husband, the daughters married to their sons-in-law, unmarried children, and their daughters' children. In these bonds, the "blood" relatives are called retarã, affinity relatives are the towadjá, and the aggregates also recognized as relatives by the bonds with the host family are the guapepó. The extended family can include many domestic groups spread over several villages (20, 22).
The Guarani understand the non-indigenous concepts of kinship (e.g., brothers, cousins, uncles, grandparents), and thus, we chose to maintain these distinctions in data collection without disregarding the existence of a context in which the family is extended. Thus, the relations between the relatives considered to be close and very close keep the exchanges active, although the nature of the non-related by kinship needs to be broadened under the perspective of extended families.
Being on the move is a way for the individual to maintain health and happiness (25). In this sphere, the sense of being in the Guarani world is added, such as the search for Yvy Marã’ey, the Land without Evils, and the mborayu, or reciprocity (20, 50). These elements favor the exchange of plants between people and villages, which end up circulating in different phytophysiognomies while strengthening social bonds, kinship, and affinity relationships (22).
Teko porã, well-being, and eco-cultural health
Within their extended territory, all tekoá (Guarani villages) are connected and, through their geographical distribution, represent the support and structure of the Mbyá world (65). Religiosity permeates the Guarani daily life, and Opy holds the position of the social, political, religious and educational center of the village (21, 22, 25). Ceremonies are usually mediated by karaí or opygua (spiritual leaders, shamans, prayers), who know how to receive and interpret divine words and have knowledge about healing and traditional remedies (5, 21, 22, 27, 66).
For the well-being and maintenance of Guarani customary practices, forest environments are essential, which permeate the reasons for migration in search of a good place to settle. Forest environments provide the essentials for health and happiness, good water and land, a source of food and medicines and direct contact with deities. Taking care of rivers, land, and forests is part of the individual and collective health that involves not only humans but also those who share these spaces in the natural and supernatural worlds, and these environments must be maintained for those that will come later because so did the ancestors (50, 67).
Although historically the Guarani have occupied the lower lands of the Atlantic Forest (68), in the archaeological record, there are Guarani sites in the three southern states of Brazil in the area of mixed rain forest and forest transition areas (10). Villages present in transition areas of phytophysiognomies (as shown in Fig. 1) can contribute to the Guarani interaction with a diversity of species and emphasize the effects of indigenous management of the Atlantic Forest landscape (see also Pereira Cruz et al. (30)). For Guarani people, dreams and visions of older people often guide decisions when considering places to live, relating the natural environments to the cosmology of the Guarani way of life (27, 67), highlighting their understanding of an intrinsic relationship between well-being and forests.
There are essential plants used in rituals that the Guarani seek to maintain. The small spaces in which indigenous lands are located, especially in southern Brazil, impose challenges to access and collect plants, such as orchids at indigenous lands near Porto Alegre and at Morro dos Cavalos (69), and medicinal plants (66). The interest in the presence of plants intended for women's health demonstrates, for example, the concern of communities to take care of everything that involves women's cycles and is also a way of maintaining traditional practices amidst social and environmental changes, without relying on medical assistance from juruá kuery (70, 71). Noelli (18) emphasizes in this sense the flexibility and structure of the Guarani medical system, which over the past centuries has sought the efficacy of both native and introduced plants to combat the entire arsenal of previously unknown diseases to which they were subjected, such as influenza, smallpox, measles, malaria, typhus, yellow fever, venereal diseases, and tuberculosis.
Historically, the Guarani have demonstrated their flexibility in dealing with the natural resources they have, in parallel with their sociocultural unity. The search for the necessary conditions for well-being and the understanding of eco-cultural health with an intrinsic link between health and forest also support the process of domestication of the landscape (72, 73). Historical and continuous interactions with forests maintain important elements in the environment for cultural continuity in a healthy and safe way. Plant exchanges and the management of certain species can also provide information about possible domestication processes that may occur at different levels (27, 28, 30) and contribute to the continuous genesis of cultural landscapes of Atlantic forests.