Knowledge and use of wild edible plants in rural communities along Paraguay River, Pantanal, Brazil

Communities located along the Paraguay River have an important knowledge on Pantanal west edge native vegetation types wild species food use. Communities that had more available vegetation types mentioned more species, but the difference was not significant. Riparian vegetation was present in all studied communities and this vegetation type holds the greatest number of known edible species. They occur in permanent preservation areas and have its importance associated to cultivated foods production. They also act as a protection against erosion, besides containing damage to water courses, among others [42]. Thus, they contribute to aquatic habitat conservation with other food sources, especially of animal origin.

Riparian vegetation seems to be important as a diet area due to its potentially edible species richness associated with local knowledge. The fact that most species can also be used as fishing bait reflects all communities in these areas contact in relation to professional, sport or subsistence fishing activities. It contrasts with the small number of aquatic species, which originate from flooding or water courses.

Wetlands in the region have high species richness [28, 29] and offer various food resources [43]. This includes Oryza glumaepatula and Oryza latifolia extensive rice fields, which dominate the landscape during the months of April and May [44]. These species were already harvested by Guató in the past [32, 45].

The condition of a species that is ceasing to be useful can be linked to poverty, nearby resource unavailability and cultural habits loss, such as mentioned by other authors [46]. The association between wild edible plants consumption and the belief that it is “food for the poor” was also recently discussed [12,47]. According to the authors, the association with poverty (cultural acceptance) is one of the limiting factors on edible wild plants consumption.

The Guató were canoeists Indians which spent most of their time navigating, having temporary camps as their residences [32]. They were considered extinct [21] for a long time and settled on cities’ outskirts or were employed on farms. Aquatic species presently used as food lack of mentioning, especially in Guató community, may be related to this condition. Guató indigenous names absence for plants names also reflects cultural heritage loss related to the language among the descendants that currently live on Ínsua island. It also shows its little influence in other communities before being abandoned or lost, since Guató edible plants indigenous names were not mentioned by any non-indigenous respondent in other communities.

Deciduous forests have useful and well-known food species for locals. However, it was the only vegetation type related to environmental problems that threatened resources availability. A resident reported fruits scarcity in the “bushes” (deciduous forest) of his community in recent years (1990s). This would happen because of deforestation in the neighboring country, Bolivia, which would be promoting birds’ migration to this region. According to him, when trying to look for fruit in the forest, the birds would have already consumed everything. Deforestation in Bolivia was among the highest in the world in the 1990s [48] and it currently continues, especially in deciduous forests [49]. In the Brazilian Pantanal, during the study period, there were no data on deforestation in dry forests. Anyway, estimates [50] indicate that the deforested area had doubled in the 2000s in relation to the deforestation made up to 1990/91 [51]. Deforestation consequences and possible pressure and restrictions on local populations native foods access as environmental changes result need to be investigated.

Wild species that were planted in backyards by residents due to their importance as bait (Pouteria glomerata from the riparian forest), or as food (Eugenia uniflora, Caryocar brasiliense and Hancornia speciosa from the Cerrado), show species interest, in order to keep them closer and more available. These species cultivation techniques and handling mastering should be further investigated.

No difference between genders was found, confirming what has been found in previous studies on wild edible plants conducted in Brazil [12,15]. Adult men in the studied communities have had enough contact with field activities, such as cattle handling, ships skipping, professional fishing and bait catching to sell to sports tourists. However, some women also hold positions that involved field activities, such as bait catching. Furthermore, in these communities, native vegetation is very close to the houses. Some information about fruit use processes, such as flours and beverages, were mentioned by older women who, due to being homemakers, are responsible for these products post-harvest processing. These communities characteristics put both men and women in a similar situation regarding the opportunity to know wild edible plants.

Results pointed to higher knowledge among the elderly, as was also observed in other studies [3,12,14]. The lack of a younger generation (Amolar) or the fact that there were few young people (Castelo) to transfer this knowledge locally impairs knowledge transmission, as noted by [3] in a study at a community in the Argentine Patagonia. Species use abandonment, such as of Oryza spp., and some processing practices abandonment, such as bocaiuva and chichas making, for example, which are now known only by a few elderly people, are no longer being taken advantage of. Thus, it is also no longer known by younger generations, impacting future knowledge on local biodiversity more elaborate uses, what involves traditional technologies that were still little studied.

In general, residents of the most remote communities always mentioned edible species. This suggests that this distance to an urban center promotes a closer relation with the environment, and increased wild products use in feeding. Although Albuquerque and Amolar communities total number of mentioned species is similar, the number of people who did not mention any wild edible species in Albuquerque was higher. Albuquerque community is the only one that has a small shop for manufactured food sale, and is also the most urbanized community [34]; it is the nearest to a city (Corumbá), where there is higher capability to buy food. Proximity to urban centers as an explanation for wild plants use reduction was also shown in the Bolivian Amazon [9] and in Northeastern Brazil [52]. The small number of species mentioned by Ínsua island residents was probably because most respondents had spent part of their lives in urban areas or had come to the site (Ínsua Island) recently (Table 1). This recent occupancy is because only after it was demarcated as an indigenous reserve, in 1993, that leaders encouraged Guató descendants return to the island.

Fruits preference observed in this study was also observed in Argentina [10] and in the Caatinga, Brazil [52]. Fruit food use is certainly related to squash high nutritional value and also to its traditional use in the region. Acrocomia aculeata, for example, was the species with the highest use value and fruit number of uses, as found in a Quilombola community in Brazil [53]. It has a copper-rich mesocarp and carotenoids, and the almond has oil, protein, fiber and minerals, such as copper, phosphorus and magnesium [54].

Acrocomia aculeata can be found in all native vegetation types, with exception of floodplains. It has traditional uses in the region, being mentioned as the best palm used by Mbayá-Guaicurú indigenous people in the nineteenth century, whose oil was used as fuel and fruits were eaten raw, roasted or dried, as stated by [55, 56]. Mbayá-Guaicurú lived in the Paraguay River basin in the second half of the seventeenth century, and Carvalho [56] states that territory expansion occurred due to the finding of areas rich in Acrocomia aculeata (Namogolidi, in Guaicuru language), which ensured feeding.

It is possible that the higher use value is related to Acrocomia aculeata multiple use as medicine, bait and construction material. On the other hand, the small number of mentions to past uses, and only by elderly people, such as almond oil use in food or as fuel, as mentioned above, alcoholic and non-alcoholic (chichas) beverages production and flour made from the mesocarp indicate that this knowledge is in decline. This was also observed for Attalea phalerata, which had low use value, although having uses mentioned in the literature as a Guató food resource [20,32] and as food resource for the Midwest region [57].

Among species whose seeds are utilized, Passiflora spp. and Senna occidentalis were highlighted. Both were used for beverages production, but were also little mentioned by some locals, as palm hearts. Senna occidentalis has its toasted seeds used for a beverage similar to coffee [36] production, which is locally called “café de fedegoso”, replacing coffee in the morning meal.

Species with underground organs and food potential, such as Jacaratia corumbensis, which was mentioned in studies in Argentina [46, 58] exist in decidual forests [26], but were not mentioned by residents. No reports in the literature were found on Jacaratia corumbensis uses by indigenous peoples of this region, but the geographical proximity to studied areas [40, 51] suggests that peoples in the past used this resource. Nascimento et al. [13] argue that roots, tubers and seeds low consumption rate represents a waste of resources with high nutritional value that would be able to supplement the population nutritional supply, especially in drier periods of the year in the Caatinga.

Abundant species with highlighted potential in the literature for economic use lack of economic utilization, such as Hancornia speciosa and Caryocar brasiliense [59,60], are related to the lack of a local or regional well-established market that stimulates this activity. It is also related to a certain distance from the communities in relation to the city, whose access is generally costly [23]. Flour made from Acrocomia aculeata mesocarp traded in a public market [36] and the fresh fruit sold in a free street market in Corumbá were among the few products on the local market (Corumbá).

This situation contrasts with other regions of Brazil, such as the Amazon, where wild edible plants may be found on the market since many years. Brazil nut (Berttoletia excelsa), for example, is today one of the main export products of the Amazon [61]. In the last decade, the Brazilian government has adopted a policy of encouraging the sustainable use of wild species. It contrasts to the previously adopted policy, especially in the 1970s, of stimulating agricultural production with deforestation for agriculture and pasture crops, and the high agribusiness incentive, on a large scale.

Plants that are marketed within communities can offer a track about resources from flora that has economic importance associated to local knowledge. These species valorization and economic exploitation can improve neglected food plants utilization and promote development (poverty reduction) and commercialization.

Wild fruits use is being stimulated in Pantanal local communities where these studies were conducted, and in other areas not included here [62]. This is aimed at highlighting wild species use in the diet, or in economic purposes, seeking also to stimulate biodiversity conservation. Among species that were the target of this study, there are Oryza latifolia and Oryza glumaepatula, which have historical value to the Pantanal and are closely related to Oryza sativa. They have economic exploitation potential and are abundant on the plains. This is an activity directed toward targeted species and communities in relation to one aspect, but these are certainly actions that need integrated policies to restrain communities’ extinction process and, along with it, related knowledge extinction.

As the field study in different communities was developed around 15 years ago, there were socioeconomic changes that may have influenced these communities nowadays. It is possible to highlight, for example, one project dealing with wild food plants developed in some of these communities, aiming to improve their incomes [62]. In another example, in the Amolar community, most of the interview elderly people died, or their families do not live there anymore. The two situations are antagonistic, because the first stimulates local knowledge and use (with wild plant food use in the diet and marketing) and the second involves elderly rural population reduction, which held more knowledge that could be shared with future generations.