Facing global markets – usage changes in Western Amazonian plants : the example of Euterpe precatoria Mart . and E . oleracea Mart

Palms (Arecaceae) are one of the most important families of useful plants, and indigenous as well as mestizo societies have developed very distinct ways of utilizing this resource. For this reason the family can serve as an excellent tool to depict the change of use knowledge over time, in particular because a considerable number of palm products has entered the global market in recent decades. Various species of the genus Euterpe are widely known under their main vernacular name Açaí. Euterpe oleracea Mart. (Fig. 1) is a clonal species that occurs naturally in periodically inundated areas in Northern South America, in particular the Brazilian Amazon, the Orinoco basin, and in costal swamps of Columbia and Ecuador (Kahn). In contrast Euterpe precatoria Mart. (Fig. 2) grows solitary, on tierra firme, and covers much the same geographic region as the previous species, but occurs also in the western Amazon basin of Peru and Bolivia [1]. The use of Euterpe oleracea has long been documented, in particular in Eastern Amazonia. There, the fruits are traditionally immersed in water, mashed, and the resulting frothy mixture is strained and drunk, or added to rice or cassava (Manihot esculenta) flour. This can provide up to 42% of local diets [2,3]. In addition, the juice is traditionally used to treat pain, flu, and fever [4], while oil extracted from the fruit is known to treat diarrhea [5]. During the last decades, E. oleracea has become a global commodity however [6]. Originally only harvested from flooded areas, the palm is now being grown in large plantations [7–17]. E. oleracea was initially commercially important as source of palm hearts [3,18], but the species has more recently attracted fame for its supposed health-promoting benefits [4,19–33]. The much wider distribution of Açaí beverages has led to a tremendous increase in price, as well as the use of quicker, non-traditional preparation techniques, depending on the fancy of the end-users [34–36]. This in turn is suspected to have led to outbreaks of orally transmitted Chagas disease [37–40]. Euterpe prectoria in contrast has been reported much more frequently for its traditional use in house construction, e.g. as posts and for thatch. During the last decades reports on the use of E. precatoria adventive roots for the preparation of medicines to treat malaria, hepatitis and other ailments have become more frequent [41]. Abstract


Introduction
Palms (Arecaceae) are one of the most important families of useful plants, and indigenous as well as mestizo societies have developed very distinct ways of utilizing this resource.For this reason the family can serve as an excellent tool to depict the change of use knowledge over time, in particular because a considerable number of palm products has entered the global market in recent decades.
Various species of the genus Euterpe are widely known under their main vernacular name Açaí.Euterpe oleracea Mart.(Fig. 1) is a clonal species that occurs naturally in periodically inundated areas in Northern South America, in particular the Brazilian Amazon, the Orinoco basin, and in costal swamps of Columbia and Ecuador (Kahn).In contrast Euterpe precatoria Mart.(Fig. 2) grows solitary, on tierra firme, and covers much the same geographic region as the previous species, but occurs also in the western Amazon basin of Peru and Bolivia [1].
The use of Euterpe oleracea has long been documented, in particular in Eastern Amazonia.There, the fruits are traditionally immersed in water, mashed, and the resulting frothy mixture is strained and drunk, or added to rice or cassava (Manihot esculenta) flour.This can provide up to 42% of local diets [2,3].In addition, the juice is traditionally used to treat pain, flu, and fever [4], while oil extracted from the fruit is known to treat diarrhea [5].During the last decades, E. oleracea has become a global commodity however [6].Originally only harvested from flooded areas, the palm is now being grown in large plantations [7][8][9][10][11][12][13][14][15][16][17].E. oleracea was initially commercially important as source of palm hearts [3,18], but the species has more recently attracted fame for its supposed health-promoting benefits [4,[19][20][21][22][23][24][25][26][27][28][29][30][31][32][33].The much wider distribution of Açaí beverages has led to a tremendous increase in price, as well as the use of quicker, non-traditional preparation techniques, depending on the fancy of the end-users [34][35][36].This in turn is suspected to have led to outbreaks of orally transmitted Chagas disease [37][38][39][40].Euterpe prectoria in contrast has been reported much more frequently for its traditional use in house construction, e.g. as posts and for thatch.During the last decades reports on the use of E. precatoria adventive roots for the preparation of medicines to treat malaria, hepatitis and other ailments have become more frequent [41].
Our presented research focused on the uses of both species in Western Amazonia (Bolivia and Peru), in order to evaluate change of usage by local communities as possible effect of the global boom in Euterpe products.

The changing use of Euterpe sp. in the Western Amazon
As late as 2010 Macia et al. [42] outlined the broader use records of palm species in Western Amazonia based on a large-scale literature review.According to this overview Euterpe oleracea had been used in the Amazonian areas of Peru and Bolivia, only by mestizo communities, and mostly for the preparation of beverages and palm hearts [43,44], and only the roots were infrequently applied as medicine, mostly for endocrineurinary system disorders.
Recent research [45,46] indicates however that the use of Euterpe oleracea has increased in recent years, and is slowly spreading from mestizo to indigenous communities, e.g. the Cocama and Awajun in Peru.In addition to the uses described above, E. oleracea is also infrequently used for construction purposes (thatch and house-posts), and the roots serve to treat anemia, as well as a galactogogue.While older participants showed a trend to know more food uses, younger participants had a tendency to mention more medicinal uses (Tab.1).
This trend however seems to have changed dramatically in the more recent past.Our own data indicate a widely spread use of Euterpe precatoria amongst all communities interviewed, without regard to ethnic background.However, we did encounter a significant difference related to participant age -in case of food uses, older participants did most frequently not mention E. precatoria as food, while younger participants often only knew the species as potential source of palm hearts and beverages.However, many of these participants indicated that they were not themselves consuming the material, but rather collected it for sale [45,46,[66][67][68][69][70] (Tab.1).

Conclusions
The plant use knowledge of local communities in the Western Amazon of Peru and Bolivia clearly depends little on their ethnic background.Differences in knowledge can rather be linked to the age of the users.Young mestizo and indigenous inhabitants are most familiar with the use of E. precatoria fruits and palm hearts or food, and know about medicinal uses, while older informants focus on the use of the species for construction and utensils.A reason for this discrepancy might be that the harvest of palm hearts inevitably destroys the resource, and thus if a species is needed as construction material, it makes little sense to destroy the resource for short-term gain, in particular if market access is very limited.The global boom  of palm hearts and later açaí fruit products, and the associated influx of quick cash, led to a replacement of the originally used products and species with others that can be sold commercially.In case of Euterpe oleracea, still only few communities in Western Amazonia know the palm at all, indicating that this species has relatively recently been introduced as reaction to the global boom of açaí products.
The fact that the older local population does hardly ever eat açaí fruits (or use them for the preparation of beverages), while essentially any other palm with soft fruits is consumed in this way, might show some relation to the Chagas disease risk mentioned above (Health, Oksen, Signori Pereira, Velente).No other palm species have been reported as source of foodborne Chagas.This could mean that the indigenous population originally avoided Euterpe sp. as food source, precisely to avoid potential illness.This hypothesis would merit further investigation.
Overall it is clear that the global commodity boom has led to a shift in the usage of Euterpe sp. from construction and utility use to various forms of food usage.This has inevitably increased the pressure on natural populations, even in the relatively remote Western Amazon, and has led to the introduction and cultivation of Euterpe oleracea.

Ethnic group Food -fruits Food -palm heart Construction Medicine -roots Medicine -fruits Utensils Art Euterpe oleracea
Use differences of Euterpe olearacea and Euterpe precatoria in the present study.