The results of the focus group discussions showed that more than two-thirds (67%) of the “wild” food plant species have associated management practices (Figure 3). Almost all plants that have associated management practices have been transplanted (18 out of 20 species, see Table 1), with the exception of Mauritia flexuosa and Manilkara bidentata that are only pruned. Sixty-one percent of all transplanted species did not include additional management practices. Among those species that included additional management practices were Artocarpus altilis, Passiflora quadrangularis, and Solanum sessiliflorum var. sessiliflorum that were transplanted and weeded; Bactris gasipaes and Myrciaria dubia that were transplanted, watered, fertilized and weeded; Theobroma cacao that was transplanted, fertilized, weeded and pruned; and Matisia cordata, which is a native fruit tree that not only was transplanted, watered, fertilized and weeded, but also protected from chickens by placing a little fence around it. None of the species was mulched. Contrarily, species like Attalea phalerata and Oenocarpus bataua did not present any management practices (Table 2).

More than half (57%) of the “wild” food plant species, including 76% of the species that have associated management practices, have been classified as weeds by scientific literature. In addition, weeds such as the introduced tree A. altilis, native climber P. quadrangularis and native shrub S. sessiliflorum var. sessiliflorum are weeded by the local population.

The most important origin of planting material was the forest, with 61% of transplanted species, followed by the market (28%) and agricultural fields (22%). The most common environments where species were transplanted were the agricultural field (83% of transplanted species), followed by the home garden (33%). This was reflected in the flows of transplanted material. For instance, the strongest flow of transplanted material was from forest to farm, encompassing 11 species; followed by market to agricultural field with five species, and agricultural field to home garden with four. Flows also included species that were transplanted from one place to another within the same environment (Figure 4).

A total of four species are managed in situ and 18 species are managed ex situ (Table 3). From the species managed in situ only two presented associated management practices (pruning, i.e., M. flexuosa and M. bidentata), whereas the other two were tolerated. The tolerated species were Passiflora acuminata and Physalis angulata, which are spared within agricultural fields and are not taken out when weeding the crop. Species cultivated ex situ include these transplanted from one environment to other (e.g., from forest to farm), within the same environment (e.g., from farm to farm) and from the market to an environment (e.g., from market to farm). All management forms, including incipient management in situ and management ex situ, include species classified as weeds by scientific literature.

Farmers perceived that the abundance of 77% of the “wild” food plants decreased during the last decade, whereas the abundance of 20% of the species increased, and the abundance of Pourouma cecropiifolia remained the same, because, as farmers clarified, they did not cut it down given that it takes too long to grow. Instead, they transplanted P. cecropiifolia from the forest to their farms to have it nearer to their homes. Fifty-seven percent of the plants that are less abundant, have been transplanted, two are pruned but not transplanted, and the remaining are not managed. Four species that are more abundant, have been transplanted and two have not. The most important motivation for transplanting a “wild” food plant was to have it close to home, mentioned for 72% of the species that have been transplanted (n = 18). Conversely, the most important reason for not transplanting a “wild” plant was the long time it takes to grow (cannot make immediate use of it), stated for 67% of the species that have not been transplanted (n = 12; Tables 4, 5).

Villagers explained that transplanting is a local strategy to ensure the presence of species that are less abundant than a decade ago, because nowadays they are unusually cultivated in the village, used as firewood, have difficulties to grow due to their ecological requirements, or are decreasing in availability, because they are not frequently used. For example, farmers explained that they have transplanted Bixa orellana from the forests to their home gardens to give color to food and juices during carnival. They highlighted that they have transplanted B. gasipaes in their farms, because they cannot find it in other environments within the village anymore, given that they cut down the trees, which were very tall, to collect the fruits. Likewise, Pouteria caimito and Inga feuillei have been transplanted near the house to be used as firewood. Regarding the “wild” food plants that are more abundant than 10 years ago, villagers explained that although some species are characterized by their favorable ecological requirements, they have been transplanted to have them close to home. For example, Inga edulis has been transplanted from farms to home gardens, and A. altilis has been transplanted from forests to farms (Table 4).

There are species like P. acuminata and P. angulata that are perceived to be more abundant than 10 years ago, and have not been transplanted by villagers because, as they stated, these plants grow like “weeds” and, in the case of P. angulata, the birds bring the seeds so there is no need to propagate them. Conversely, there are species that despite their decreased abundance, have not been transplanted. Farmers explained that their abundance has decreased, because they cut down the trees to sell the timber, use the firewood, collect the fruit, or make a new agricultural field. They argued that these species, with the exemption of Genipa americana and M. flexuosa, have not been transplanted because it takes them too much time to grow. They also indicated that G. americana is not commonly used by the mestizos but mainly utilized by indigenous communities. Although they cut down the trees of M. flexuosa to collect the fruits, they explained that they cannot transplant it because it requires a lot of soil moisture, which they do not have in the village (Table 5).

The “wild” food plants gathered in Pueblo Libre (n = 30) could be classified into six groups, according to management forms and local perceptions (mainly in relation to species abundance). Four groups present species classified as weeds by scientific literature (Figure 5).

Group 1 includes species that are not managed although famers perceived that they have decreased in abundance. Informants reported that the abundance of all species from this group, except for G. americana, has decreased because they cut down the trees to sell timber, to collect fruits, for firewood or when slashing for a new agricultural field; but they do not transplant them because it takes them too much time to grow. For example, farmers cut down the trees of O. bataua and Phytelephas macrocarpa to collect the fruits. Farmers mentioned that although G. americana decreased in numbers, it is not transplanted, because they do not use it frequently. The other species that belong to this group, are Inga sp., Euterpe precatoria, Astrocaryum sp., Spondias mombin/Spondias venosa, and A. phalerata. This group includes three species classified as weeds (I. sp., S. mombin /S. venosa and A. phalerata). All species in this group are native.

Group 2 encompasses species with non-agricultural incipient management, managed in situ and with a perceived increased abundance. This group includes the two species that are tolerated (P. acuminata and P. angulata), which farmers mentioned as growing like “weeds.” P. angulata has also been classified as weed by the literature. Both species in this group are native.

Group 3 includes species with non-agricultural incipient management, managed in situ and with a perceived decreased abundance. This group includes the two species that are pruned but not transplanted (M. flexuosa and M. bidentata). Informants stated that they have decreased in abundance because they cut down the trees to collect the fruit or to sell the timber; and they do not transplant them because M. flexuosa requires a lot of soil moisture and M. bidentata takes a long time to grow. None of these species has been classified as weed. Both species in this group are native.

Group 4 comprises species cultivated ex situ that farmers perceived having a decreased abundance. The reasons for decreasing in numbers include explanations related to little use or knowledge about the uses of the plant, unfavorable ecological conditions, and cutting down the trees for firewood or to collect the fruit. The main motivations to transplant them are related to use-value (having the plant close to home, to sell it and to give color to juices). The species belonging to this group are B. orellana, M. dubia, Smallanthus sonchifolius, P. caimito, I. feuillei, Poraqueiba sericea, S. sessiliflorum var. sessiliflorum, P. quadrangularis, Dioscorea cf. trifida, Pachyrhizus tuberosus, C. allouia, Colocasia esculenta, and B. gasipaes. All the species from this group have been transplanted, and four of them presented additional incipient management practices (M. dubia, S. sessiliflorum var. sessiliflorum, P. quadrangularis, and B. gasipaes). Six species from this group have been classified as weeds (B. orellana, S. sessiliflorum var. sessiliflorum, P. quadrangularis, D. cf. trifida, P. tuberosus, and C. esculenta). C. esculenta and D. cf. trifida are the only species that have been introduced to the region (from Australasia and the Caribbean respectively).

Group 5 includes a native species, i.e., P. cecropiifolia, which is cultivated ex situ and has a perceived unchanged abundance. In contrast to the species from the previous groups, as mentioned before, this is the only plant that farmers do not cut down because it takes a long time to grow. This plant has not been classified as weed.

Group 6 encompasses species that farmers cultivated ex situ although they perceived an increased abundance. They explained that the abundance of these plants increased because of favorable ecological conditions. The motivations for transplanting these species are related to use-value. The species that belong to this group are T. cacao, I. edulis, A. altilis, and M. cordata. All species, except I. edulis, presented additional incipient management practices. M. cordata is the only species that has not been classified as weed. All species are native, except for A. altilis, which has been introduced from Asia and the Pacific.

This study, which was based on focus group discussions conducted with mestizo farmers, showed that more than two-thirds of the “wild” food plant species in the study village are managed, and most of them have been transplanted ex situ. Certainly, humans have intervened in the populations of wild species throughout the world, for example, changing the diversity and density of food plants by transplanting or introducing new species to an environment (Wiersum, 1997a; Daly, 2014; Parrotta et al., 2015). The use and management of wild food plants have already been reported in Latin America, for example, among the Nahua and Mixtec communities (Casas et al., 1996) and in Santa Maria Tecomavaca (González-Insuasti and Caballero, 2007) in Mexico, among the Mapuche in Chile (Daly, 2014), in the Monte region in Argentina (Ladio and Lozada, 2009), in the Bolivian Amazon (Reyes García et al., 2005; Thomas, 2012) and Andes (Vandebroek and Sanca, 2007), in Pernambuco in Brazil (Cruz et al., 2013), and in Cuba (Volpato and Godinez, 2007). Furthermore, the management of wild food plants has also been documented in Africa, for example in the Collines region in Central Benin (Avohou et al., 2012) and Central Shewa of Ethiopia (Feyssa et al., 2012); and Asia, for example in Northeastern Thailand (Cruz-Garcia and Price, 2014b), among others.

Defour and Wilson (1994) reported a total of 131 wild food plant species for all Amazonia, which mainly include trees and palms, consumed by indigenous communities. Certainly, the study of management and domestication of food plants in the Amazonia has largely focused on fruit trees (Clement and Villachica, 1994; Clement, 2006; Miller and Nair, 2006); and the documentation of food plant management in this region has mainly focused on indigenous communities (e.g., Reyes-García et al., 2006; Thomas, 2012), but not on mestizo villages. The Botanical Garden—Arboretum El Huayo (JBAH) from the Universidad Nacional de la Amazonía Peruana (National University of the Peruvian Amazon) located in Iquitos, Peru, possess a collection of 46 species of edible fruit plants reported in surrounding communities (Freyre, 2003). Taking into account these numbers, the amount of food plants documented by using focus group discussions for Pueblo Libre village (n = 30 species) might seem low. However, compared to other studies conducted in the Amazonia, the number of “wild” food plants documented for Pueblo Libre is higher than those reported by Reyes-García et al. (2006) for the Tsimane' communities of the Bolivian Amazon (n = 18), and very similar to the number of food species reported by Vásquez and Peláez (2015) for the inhabitants of Berlín village in Bagua Grande, Peru (n = 29).

Ucayali has been highly affected by high deforestation rates (Smith et al., 2006; Miranda et al., 2014; Porro et al., 2015). Land use change, deforestation, and unsustainable management of natural resources are the main drivers of loss of biodiversity and, consequently, decrease of wild food plants (Daly, 2014) and other underutilized species. This decline affects the food security of rural families directly (e.g., availability and accessibility to food) and indirectly (e.g., modifying the ecological conditions where species grow) (Van Noordwijk et al., 2014; Agarwal et al., 2015). Management practices: (a) allow rural families to have sufficient food and nutritional diversity by increasing the availability and access to wild food plants and other underutilized species, and (b) favors the conservation of these species in highly intervened anthropogenic environments when forests decline (i.e., by bringing planting material from forests to farms and home gardens). Certainly, the dietary diversity and nutritional quality of the diet of hundreds of millions of people in the world rely on the consumption of wild food plants and other underutilized edible plants (Grivetti and Ogle, 2000; Johns and Eyzaguirre, 2006; Heywood, 2011).

There are two points of recommendations for future research in relation to management and domestication of food plants by mestizo villagers (or immigrant communities). The first is to understand the historical process of knowledge acquisition about Amazonian flora by mestizos from indigenous peoples and/or by experimentation. The second is to assess the historical management of these species by mestizo villages. For instance, are the practices described in this study new ones that emerged as a response to deforestation and loss of biodiversity? Or are they practices that existed among mestizo villages before deforestation rates started to increase, and were adjusted to the new settings (i.e., intensifying human induced movement of biodiversity from forests to more intervened anthropogenic environments)? Such additional studies would shed light on understanding historical processes of management and domestication by non-indigenous societies.

The findings of this study provide evidence that mestizo farmers transplant “wild” food plant species across different environments within the farming landscape. This emphasizes the spatial and seasonal complementarity of different anthropogenic ecosystems for food provision, which is particularly important for families living in the forest-agriculture interface. The importance of this complementarity for the food security of rural families has been also reported in other regions of the world, for example in Northeastern Thailand (Cruz-Garcia and Price, 2014a) and West Java in Indonesia (Abdoellah and Marten, 1986). Certainly, Frison et al. (2011) emphasized that a major basis of dietary diversity is the diversity of environments within farming landscapes, which was also illustrated by this study in Ucayali.

The key role played by forests, agricultural fields, and home gardens for provisioning food to rural households has been highlighted by various studies around the world. For instance, the importance of forests for food security has largely been acknowledged in scientific literature (e.g., Arnold et al., 2011; FAO, 2011; Sunderland et al., 2014); as well as the importance of multiple habitats, ranging from terrestrial to aquatic ones, that diversified agricultural fields encompass to facilitate the growth of multiple food species (e.g., Altieri and Anderson, 1987; Cruz-Garcia et al., 2016); and the importance of home gardens not only as source of food but also for processes of domestication and biodiversity conservation (e.g., Miller and Nair, 2006; Galluzzi et al., 2010; Cruz-Garcia and Struik, 2015; Freedman and Stoilova, 2015). Additionally, it is important to highlight that not only the farming landscape but also the market plays a key role in providing planting material, which has also been reported in other regions of the world (e.g., Ruiz-Pérez et al., 2004).

Ogle and Grivetti (1985) in their botanical dietary paradox highlighted that wild food plant gathering increasingly occurs in more intervened anthropogenic environments rather than less disturbed environments, i.e., forests, in the face of deforestation and land use change. However, the results of this study go beyond the botanical dietary paradox, showcasing that humans have a more active role in ensuring the availability of food species, for instance supporting the flows of planting material from less to more intervened environments. This was observed in the following findings: (a) the human induced movement of “wild” food plants across the landscape occurred for all transplanted species in the study site; (b) the most common source of planting material was the forest (for 61% of transplanted species); (c) informants constantly highlighted the need to have “wild” food plant species closer to home (for 72% of transplanted species), and (d) villagers usually bring planting material from less to more intervened environments, i.e., from forests to agricultural fields, from forests to home gardens, from agricultural fields to home gardens. Certainly Zohary (2004) highlighted that human selection leads to the dispersal of plant populations toward more disturbed anthropogenic ecosystems. The movement of planting material is necessary in order to ensure the availability of wild food plants and other underutilized species given scenarios of increasing deforestation. Undoubtedly, the importance of agricultural fields and home gardens as recipients of plant genetic material has to be taken into account in agricultural interventions.

The use of cultural domains, capturing the emic or native's point of view, is a starting point of ethnobotanical research (Borgatti, 1999) that can be very useful for the study of wild food plants and domestication, given that different socio-cultural groups perceive and conceive the world differently according to their own social, historical, cultural and environmental conditions and experiences (Brosius et al., 1986). Through comparing the list of native “wild” food plants from Pueblo Libre with the results of Clement (1999) and Levis et al. (2017), it was possible to see that 10 species that were categorized as “wild” by villagers, were domesticated before European contact, whereas nine were either semi-domesticated or presented incipient domestication by that time (see Table 6). Clearly, villagers and scientists have different classifications for “wild” and “domesticated,” as previously highlighted by Michon and De Foresta (1997) and Clement (1999).

Interestingly, some species of “wild” food plants that were domesticated before European contact, are nowadays treated as “wild,” as emphasized in the mestizo's emic conceptualization of “wild” food plants where “wilderness” is associated with species that “do not require much care” (Cruz-Garcia and Vael, 2017). This was expected, given that a significant part of the crop genetic resources was lost—alongside traditional knowledge—with the eradication of 90–95% of the Amazonian population after European contact (Clement, 1999), and consequently it is still possible to see that domesticated species are nowadays dominant across the Amazon forest (Levis et al., 2017). Certainly, the domesticated species reported by this study, did not exhibit management patterns in an intensity expected for domesticates, for instance fully depending on human intervention for survival (González-Insuasti and Caballero, 2007). For example, although B. gasipaes was domesticated during pre-Colombian times (Clement and Urpí, 1987), it was listed as a “wild” species by the informants. They transplant B. gasipaes to their agricultural fields, where they collect the chonta (inner core of the stem) and fruits for food (Cruz-Garcia and Vael, 2017), bringing the planting material not only from the market but also from the forest. This species is watered, fertilized, and weeded, but neither pruned nor protected.

Conversely, T. cacao was semi-domesticated before European contact, but nowadays most populations are domesticated. Families from Pueblo Libre, however, not only manage the species in the agricultural field with the objective to sell the seeds in the market, but also gather and consume the fruits of non-transplanted, non-managed individuals of T. cacao that are growing in the forest (Cruz-Garcia and Vael, 2017). Another example is I. edulis, which was semi-domesticated before European contact, but nowadays is domesticated throughout Amazonia for its fruits and wood (Clement et al., 2010). Undoubtedly, González-Insuasti and Caballero (2007) explained that a species could be managed differently in different places and times, and Cruz-Garcia and Price (2014b) stated that domestication is a locally differentiated concept and process. Clement et al. (2010) also explained that domestication as a process occurs at population level (not at species level); therefore it is not correct to say that a species is a domesticate unless all its wild populations are extinct, which is unusual. Instead they recommended to affirm that a species “exhibits domesticated populations” that, for this study in Ucayali, might be the case of T. cacao and I. edulis.

It would be interesting if future studies evaluate the management and motivations to manage wild food plants for the different indigenous communities in Ucayali, for instance, to assess how do they conceptualize the cultural domain of “wild food plant,” which species do they classify as part of this cultural domain, and which management practices and forms do they exhibit. Do they classify the species of this study as wild or as domesticated? Do they recognize different species as wild food plants? Do they manage those species that have been domesticated before European contact (according to Clement, 1999; Levis et al., 2017) with higher intensity than mestizos?

Another term that deserves further discussion is “weed,” which has historically been defined as “a plant growing where it is not wanted” (Mortimer, 1990), or, contrarily as “a plant whose virtues are yet to be discovered” (Perrins et al., 1992). Although most agronomists and agricultural extension officers recommend their eradication to favor crop production, 89% of the most aggressive weeds in the world are edible (Rapoport et al., 1995) and several of them are highly nutritional (Duke, 1992). Certainly, the consumption of weeds has been reported throughout the world (Grivetti et al., 1987; Duke, 1992; Tanji and Nassif, 1995; Casas et al., 1996; Díaz-Betancourt et al., 1999; Pieroni, 1999; Turner et al., 2011; Cruz-Garcia and Price, 2012). Likewise, the results of this study showed that more than half of food plant species reported in the village have been classified as weeds by scientific literature (HEAR, 2007). In addition, 76% of these “weeds” have been transplanted by the villagers in order to increase their availability and to have them closer to home. Indeed, “weeds” exhibited different management forms: (a) incipient management in situ (toleration) despite their increased abundance (group 2), (b) managed ex situ due to their decreased abundance (group 4), and (c) managed ex situ despite their increased abundance (group 6). Therefore, none of both definitions of “weed” adjusts to the species documented by this study: they are tolerated or managed in the place where they are growing, and their virtues have already been discovered (i.e., as food).

It might also sound somehow contradictory that species that have been classified as domesticates by scientists—as some food plants reported by this study—have also been classified as weeds by other scientists. However, on the one hand, this can be explained by the fact that weed classifications are controversial, given that the way scientists define weeds and classify species as weeds depend on their disciplinary background (Perrins et al., 1992). On the other hand, crops might become weeds in other parts of the world, depending on the biological characteristics of the species, the environment where it is growing and the associated management practices (Harlan, 1965).

Mestizo farmers' motivations to manage “wild” food plant species affect management practices and forms. Management, including human induced movement of planting material across the landscape, influences: (a) artificial selection and, consequently, evolution; and (b) the availability and distribution of species across the farming landscape and, consequently, their ecology. The results of this study, based on focus group discussions, showed that farmers' motivations belong to two major groups: motivations related to cultural importance, particularly in relation to use-value, and motivations related to perceived abundance. These will be discussed in the following paragraphs.

Human management practices usually focus on the preservation of culturally important species. Although, as part of this study we did not directly ask informants about the cultural value of each species, culture was captured through the study of motivations to manage “wild” food plants, particularly in relation to species use-value. This is reflected in the following: (a) villagers transplanted almost three-fourths of the species to have them close to home, which facilitates their availability and access for frequent use; (b) informants also emphasized the use of species as food and medicine, or their use for coloring food and drinks, and for firewood; (c) the most common reason for not transplanting a species, accounting for more than two-thirds of the species that have not been transplanted, was the long time it takes to grow, what implies that villagers cannot make immediate use of it. This is aligned to the findings of various authors that have documented the influence of cultural importance, including use-value, on farmers' incentives to manage a species (e.g., Casas et al., 1996; Guijt, 1998; Ogle, 2001; González-Insuasti et al., 2008, 2011; Blancas et al., 2013).

Human management practices also focused on the preservation of species perceived to decrease in abundance. For instance, more than half of the species that were perceived to be less abundant, were transplanted, plus two species that were not transplanted but presented incipient management practices. Likewise, it has been reported by other studies that decreased abundance (or perceptions of a species rarity) are directly related with a farmers' decisions to manage a species (e.g., Stoffle et al., 1990; Cunningham, 1993; Price, 1997; Blancas et al., 2013, 2014).

Although the results of this study showed that human adaptation to rapidly changing environments (i.e., under scenarios of deforestation) promotes the management of food species and their movement across the farming landscape, the findings also reported the presence of destructive harvesting practices. For instance, villagers cut down trees to collect fruits (four species), for timber (four species), for firewood (two species) and when slashing and burning (one species), accounting for almost half of the species that have decreased in abundance. Whereas some of these species are transplanted to home gardens (but cut down in forests and agricultural fields), others are not transplanted because of—as villagers mentioned—the long time it takes them to grow. This is not surprising in the deforestation frontier, where multiple stakeholders, including villagers themselves, contribute to forest loss. For instance, it has been documented that timber production is facilitated by legal and illegal channels of trade, which are more available for mestizo upland villages in Ucayali than for mestizos living in lowlands or indigenous communities (Porro et al., 2015). The presence of unsustainable management practices related to useful wild plants has also been reported in other regions (e.g., González-Insuasti et al., 2011; Blancas et al., 2013). In these cases, it is necessary to promote sustainable management practices that favor the conservation of important wild food plants and other underutilized species. For example, local organizations are teaching the communities situated in the buffer zone of the Cordillera Azul National Park (Peruvian Amazonia) sustainable practices to collect the fruits of M. flexuosa without cutting down the trees (CIMA, 2012). This kind of initiatives is very important and necessary for ensuring the conservation of valuable food species, particularly those whose populations are decreasing in the Amazon deforestation frontier. Furthermore, it is necessary to implement interventions that simultaneously aim at environmental conservation, social equity, and sustainable livelihoods (Porro et al., 2015).

The main constraint of this study was that the results obtained were not suitable to generalization for larger populations, given that the data collection was based on focus group discussions. For instance, a limitation of participatory methods, like focus groups, is that their outputs do not allow statistical estimations (Kumar, 2002; Chambers, 2012). However, focus groups capture group perspectives and provide reliable information on topics that are significant for marginalized communities (Bernard, 2002). It is important to emphasize that the results from this study should not constitute the endpoint for decision-support processes, but should rather constitute the exploratory and hypothesis generating stage of future quantitative scientific projects. In this way, this study opens the possibilities for future in-depth and quantitative studies on management perspectives, for example aimed at understanding how motivations to manage wild food plants are shared within and among socio-cultural groups. In addition, future studies should take into consideration issues related to gender, education, wealth and geographical location, which affect the ways people interact with plants (and, consequently, people's motivations to manage them). This is certainly necessary, given that the study of people's motivations contributes to understanding the reasons behind management decisions and, ultimately, domestication.

The author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.