Ethnobotanical Study on Wild Edible Plants in Metema District, Amhara Regional State, Ethiopia

,


Introduction
Wild edible plants are plant species that are used as a food source for humans that fourish in their natural environment without being cultivated or domesticated [1][2][3][4]. Traditional societies throughout the world built up a wealth of wild edible plants' knowledge during prolonged interactions with the natural world [5] and use the wild plant resources to fulfll their needs [6]. Te consumption of wild edible plants seems more common and widespread in food insecure areas, leading to the notion of "famine foods" [4][5][6][7]. Tey are also used as staple food [8] since they are nutritionally rich and can supplement especially vitamins and micronutrients [9]. Tis could solve the micronutrient defciency problem for the approximately two billion people that make them more susceptible to disease worldwide [10] and especially in developing countries [11]. Tey can also ofer an alternative source of cash income for poor communities [8].
Likewise, in Ethiopia, the local people have a wider knowledge, tradition, and opportunity of using wild edible plants despite the variation in age, sex, time, and season [12]. Te wide range of climatic and edaphic conditions in the country permitted the growth of a variety of wild food plants [13]. Studies revealed that about 8% of the nearly 7000 higher plants are edible [14]. However, the bulk of useful plant parts collected from natural vegetation stocks are shrinking with degraded environment and is faced with a substantial reduction [15]. Along with this, the indigenous knowledge system descended from Ethiopia's multiethnic, cultural, and foral diversity is not documented fully and is eroding [16,17]. More recently, some ethnobotanical studies have been undertaken in some parts of the country [4,16,[18][19][20][21]. However, the majority of these studies have dealt with medicinal species and little emphasis has been given to wild edible plants [18,22,23].
Metema District, characterized by having a semiarid environmental condition and recurrent drought [23], is among the Districts of Amhara Region, Ethiopia. From prior feld experiences and reconnaissance survey, it was found that indigenous communities in Metema District are often dependent on wild edible plants. In this area, there are plant species that have tremendous importance for food security and market income, but scientifc studies on wild edible plants are lacking. Despite this, the vegetation with the associated indigenous knowledge is being lost due to the rapid increase of the population size that exposed unwise use of the plant resources. Before all of the resources are completely depleted, ethnobotanical research is essential for producing scientifc data that can be used to build the sustainable usage of the biological resources (wild edible plants) [24]. Tus, documenting wild edible plants with the associated indigenous knowledge before their complete lose is crucial and timely. In addition, the result of the study could be valuable to concerned bodies so as to develop appropriate managerial interventions. Terefore, the objective of this study was to assemble information on wild edible plant species used as food along with their associated indigenous knowledge, threats, and management practices in Metema District.

Description of the Study Area.
Metema District is located in West Gondar Zone of Amhara Region about 900 km far from Addis Ababa, the capital of Ethiopia, and 180 km west of Gondar town. Genda Wuha is the capital of the District. According to Agricultural Ofce [25], the total area of the District is about 440,000 hectares. Metema is predominantly rural encompassing one town and 17 rural kebeles (Figure 1). Te District is bordered by Quarra and Alefa in the south, Chilga in the east, Tach Armachoho in the north, and Sudan in the west [26]. A total of 110,231 people existed in the District of which Orthodox Christianity followers were the dominant (83.4%) and the remaining 16.5% were Muslims [27]. It is the home of Amhara, Agaw, Kimnat, Tigrie, Oromo, and Gumuz ethnic groups [26].
Te altitude of the District ranges from 550 to 1608 m above sea level [28] with harsh (hot) climatic conditions. Te mean annual temperature of the study area is 26.2°C, ranging from 15.7°C-41.0°C. Te mean annual rainfall of the area is 1008 mm with unimodal rainfall patterns having maximum and minimum monthly rainfall of 257.6 and 0 mm respectively ( Figure 2).

Te natural vegetation of Metema is largely composed of
Combretum-Terminaliabroad-leaved deciduous woodland type growing predominantly on vertisol (black soil) [26,28,29]. Forests and rangelands are the major (72%) land use types [25]. Sesame, cotton and sorghum are major crops and goats and cattle are the main livestock productions.

Study Sites and Informant Selection Techniques.
Study sites and informants were selected based on the recommendation of local authorities and elders during the reconnaissance survey. Accordingly, eight Kebeles (the smallest administration unit) as study sites ( Figure 1) were selected purposively based on vegetation cover and key informants' availability. Likewise, general and key informants were selected using systematic random and purposive sampling techniques respectively following Martin [30]. Numbers of households were used to select general informants through systematic random sampling techniques and prior information from the inhabitants was used to identify key informants using purposive sampling techniques. Both male and female informants within the age range of 20-85, who lived over ten years in the study area, were participated. Informants lived over ten years were considered during informant selection since people lived in one particular area for long period of time are believed to have good shared indigenous knowledge or develop rich indigenous knowledge about plant uses (wild edible plants). In addition, long lived informants can give accurate data and able to explain their indigenous knowledge confdently using their well-developed experiences. Accordingly, 80 general informants and 48 key informants were interviewed to collect ethnobotanical data.

Ethnobotanical Data Collection. Following Coton [5] and
Martin [30], data were collected using individual interviews, guided feld walks, focus group discussion, and market surveys through semistructured questionnaires in two rounds (March to May 2020 and August to December 2020). Individual interviews were done with general and key informants using checklists. Te checklists of the interview were focused on informants' demographic profles (age, sex, duration of residency in the area, education level, religion, and marital status). In addition, the checklists also emphasized on wild edible plant species local name, parts used, mode of preparation, condition of utilization marketability, and traditional conservational practices. To confrm the validity and reliability of the information given by the informants on the same topic, informants were interviewed thrice or more time. As result, only the responses of an informant which were similar to the former response were taken as correct data.
Guided feld walks were used to collect data on plant habit, habitat, and additional information which were not addressed during individual interviews. Wild edible plant specimens were collected for identifcation during guided feld walks. Specimen identifcation was made in the University of Gondar, Ethiopia, by using published volumes of the Flora of Ethiopia and Eritrea [31][32][33][34][35][36][37][38]. Qualitative information about indigenous knowledge transfer system, current status, threats, and conservation practices of the wild edible plant species were collected using focus group discussion with selected key informants. Te marketability of wild edible plant species was assessed in the local markets of Genda Wuha, Kokit, and MetemaYohannes towns. During data collection, oral permissions were obtained from Metema District administration, agricultural, and kebele ofcials as well as informants after thorough discussion about the study objectives.

Ethnobotanical Data Analysis.
Ethnobotanical data were analyzed using descriptive statistics through Microsoft Offce Excel Spreadsheet (2010) and SPSS version 20 following Cotton [5] and Martin [30]. In addition, ethnobotanical data were verifed and validated using informant consensus, preference ranking, and direct matrix ranking following the previous authors [3,5,39].
Informant consensus was analyzed for ten most frequently reported wild edible plant species so as to identify the most cited wild plant species in the study area following Phillips et al. [40]. Preference ranking exercise was done for seven wild edible plant species based on their preferred taste reports using ten experienced key informants following the previous authors [5,39]. Te highest value (7) was given to the most preferred species and the lowest value (1) for the least. Direct matrix ranking was computed using fve key informants for fve multipurpose wild edible plant species that had higher roles for the livelihood of the community following previous works [5,30,39]. For direct matrix analysis, traditional medicine, food, fodder, fuel wood, cash income, agricultural tools, construction, and shading attributes were used. Te highest value (8) was given to the most preferred use value and the lowest value (0) to no use of the species. Finally, plant species were ranked based on the sum of each score.

Indigenous Knowledge on Wild Edible Plants.
Informants' report on wild edible plant species (Supplementary Table 1) indicated that the local communities use the plants for food during hunger and normal times. However, there was indigenous knowledge variation on age and sex regarding the number of wild edible plant species reported. Signifcant diferences (P < 0.05) were obtained by independent sample t-test between males and females on the number of wild edible plant species they listed (Table 1). Males reported a greater number of wild edible plant species (Table 1). Te test also confrmed that there was a signifcant diference in the number of wild edible plant species   (Table 1). Elder informants, whose ages were between 51 and 85 years, reported a greater number of wild edible plant species.

Wild Edible Plant Species.
A total of 44 wild edible plant species distributed in 34 genera and 25 families were recorded. Trees accounted for a higher proportion of wild edible species (59.09%) (Figure 3). Fabaceae and Moraceae consisted of the higher number of edible plant species (6, 17.14% each) followed by Malvaceae and Tiliaceae (6.4% each) and the remaining fve and sixteen families were represented by two (4.54%) and one (2.27%) species, respectively, ( Table 2).
From the total wild edible plants, 33 (75%) species were used as supplementary foods and 11 (25%) species were used during famine (Supplementary Table 1). Te wild edible plant species were distributed in the natural habitat except for Cordia africana and Moringa stenopetala which were found in the homegarden and Hibiscus esculentus and Corchorus olitorius were found in farmlands. While Plumbago zeylanica existed in the wild and farmlands (Supplementary Table 1).
Informant consensus showed that 24 wild edible species were cited by over 20 informants while Terminalia laxifora was reported by only one informant (Table 3 and Supplementary Table 1). Informant consensus analysis on the 10 most repeatedly reported species showed that Diospyros abyssinica was the most preferred species with 60.94% consensus followed by Balanitesa egyptiaca (56.25%), whereas Ekebergia capensis (28.91%) was the least preferred species (Table 3).
In addition, preference ranking result showed Diospyros abyssinica ranked frst in terms of taste followed by Adansonia digitata and Cordia africana, respectively, whereas Ziziphus spina-christi stood last (Table 4).

Parts Used and Mode of Consumption of Wild Edible
Plants. Fruits were the most edible plant part (66%), whereas fowers were the least with 2.1% (Table 5 and  Supplementary Table 1) and the edible plant parts were gathered at diferent months of the year (Supplementary Table 1). With regard to mode and condition of utilization, fresh forms were used more frequently (36, 81.8%) followed by both fresh and dried forms (13.6%). Most of the edible products (79.55%) were eaten in their raw forms and only 20.45% of them were eaten after cooking along with other ingredients (Supplementary Table 1). In addition, informants reported that raw forms were easy to eat with their natural taste in the wild environment.

Income Generating Role of Wild Edible Plant Species.
In addition to their household consumption, ten wild edible plant parts were marketable ( Table 6). All of the edible plant parts were fruits with the exception of Corchorus olitorius which had marketable leaves. From these, three species, Temarindus indica, Balanites aegyptiaca, and Adansonia digitata were exported to the Republic of Sudan with higher cost for oil extraction. From exportable wild edible products, Balanites aegyptiaca was the most expensive species followed by Adansonia digitata and Temarindus indica, respectively. Te remaining seven species were sold in the local markets. Ziziphus spina-christi was the cheapest one due to its higher availability in the area. Tey provided an opportunity to supplement households' income in the study area especially the poor to meet their basic needs.

Other Uses of Wild Edible
Species. In addition to food value, the wild edible plant species had many other uses to the local community of the District. Most of the species (33, 75%) were used as animal fodder and 25 (56.82%), 20  (Table 7).

Treats and Conservation Practices of Wild Edible Plants.
Plant species in general and wild edibles, in particular, have been decreased as a result of agricultural expansion and other livelihood activities such as construction, intentional fre, frewood collection, charcoal production, constructional materials collection, and resettlements. Despite this, conservation activities were not given proper attention.
Most of the plants were freely available in the communal lands without proper management, with the exception of high valued forests containing incense producing Boswellia papyrifera and gum producing Acacia species. However, some traditional practices helped to conserve plant species. On farmlands, large trees were allowed to grow sparsely primarily for shade value. In addition, religious dogma, taboos, and local rules were used practically to conserve plants. For instance, cutting plants in Orthodox Tewahedo Church compound is considered as a great sin. Likewise, cutting of Ficus species that were used as a shade during social afairs is considered as taboo.

Discussion
Nearly equal proportion of male and female participants might be good representatives of the study area population. However, the signifcant knowledge diference between the two groups might have a direct relation with the activities they regularly engage. In the area, males mostly spent their time out of their homes even for more than a week by performing diferent agricultural practices. Tis might lead them to be more knowledgeable than females and this is supported by the report of Wondimu et al. [21]. Likewise, signifcant knowledge variation between the two age groups might be observed due to rapid modernization that easily     International Journal of Forestry Research 5 divert the attention of the young generation and this will be aggravated in the near future since documentation is not a trend of the local people. Tis is in agreement with other similar studies [41,42]. Substantial number of wild edible plants recorded in a study area showed that the local people have good indigenous knowledge. Wild edible plant species documented in this study were found greater than the fndings of Wondimu et al. [21], Assefa and Abebe [23], Seyoum et al. [43], Ayele [44], and Tebkew et al. [45] which were 41, 30, 30, 24, and 39 species, respectively, whereas a relatively higher number of wild edible plant species (46, 77, and 55) were recorded by Bahru et al. [46], Ashagre et al. [41], and Berihun and Molla [47], respectively. Te variation of wild edible plant species among the diferent study areas could be the diferences in culture, ethnicity, vegetation cover, and socioeconomic activities of the people. Other ethnobotanical studies [42,48] reported similar justifcation. Te study area shared 28 wild edible plant species with Chilga District [19], 18 with Quara District [45], 12 with Bullen District [47], 11 with Awash National Park and its bufer areas [46], and 16 with Lowland Areas of Ethiopia [49]. Te higher similarity of wild edible plants of the study area with Quara and Chilga Districts [19,45] might be due to similar environmental conditions, vegetation cover, and indigenous knowledge practice among communities as they are adjacent Districts. Similar records of wild edible plant species as food in diferent areas of Ethiopia confrm their function for food security. In this regard, diferent fndings in Ethiopia [9,23,[44][45][46]50] showed that edible wild plants are essential components of daily food intakes and had a wide role in maintaining food security if conservation priorities are given to them.
Unlike herbaceous species that survived during the rainy season only, year-round availability of woody species make them to contribute more as wild edible plants in semiarid environmental condition of the study area. In line with this, previous studies [23,42,51] reported that dry land agroecology is mostly endowed with shrubs and trees. Hence, woody wild edible plant species have tremendous importance for food security and other values in the area. Te higher proportion of trees as wild edible uses was also reported with other similar studies elsewhere in Ethiopia [19,52,53]. Similarly, the vegetation diversity study in Metema District [54] showed the highest number of tree species. Te existence of higher number of wild edible Ficus species in the family Moraceae in Ethiopia and elsewhere [51,55,56] contributed for its dominance. In addition, adaptation potential of wild edible plant species in Moraceae and Fabaceae over wider range of altitudes and agroecological regions enabled them available in higher proportion [42,57]. Te dominance of Fabaceae and Moraceae was also reported in previous studies [19,44,45,53].
Te variation in the frequency of citation (informant consensus) and preference ranking of wild edible plant species could be their diference in agroecological distribution and indigenous knowledge sharing. In addition, the   [21] and the 4th preference in Burji District [41]. Generally, the most cited wild edible plant species could have great potential for food purpose in the community and needs conservation priority. Availability of a higher proportion of fruit-bearing trees and shrubs might make fruits the most commonly used wild edible plant part. Ripe fruit is simpler to consume and ease of processing, making it superior to the other parts [50]. In addition, studies in other areas of the country [13,21,42,44,50,53,58] reported that fruits possess more nutritive feshy part and taste than other plant parts [59]. However, other studies [23,41,44] reported that leaves were the most important edible parts. Te variation of reports in wild edible plant parts could be the disparity of traditional knowledge in the community, climate condition and vegetation types of the study area, and socioeconomic activities of the community and quantity and quality of edible plant parts as it was reported by Anbessa [58]. Te preference of using fresh forms for the edible purpose would have tremendous importance to alleviate both starvation and thirst. In addition, using fresh forms might be easy for preparation and retain its natural content. Other studies also reported the use of fresh forms for edible purposes [19,50]. However, the use of dried wild edible plant parts would have great value to alleviate future food insecurity if the resources are scarce and seasonal.
Likewise, the preference of raw consumption indicated that the plant parts are eaten as soon as they are gathered from the place where they are found in the wild. Other research fndings [58,60] also reported the preference of raw forms for consumption. Te fndings of cooked vegetables in the study area could be helpful to develop the habits of using wild edible plant parts after processing. However, overcooking of wild edible plant parts might be causing the loss of the natural organic nutritive content and taste. Generally, eating wild edible plant parts after cooking and processing would have roles to reduce toxic nature and add taste and favor. Te availability of the edible plant parts at diferent periods of the year would provide the communities to access the edible parts at diferent times of the year. Te existence of diferent wild edible plant parts at diferent periods of the year was also supported by Tebkew et al. [45].
Income derived from the sale of wild plant parts has particular importance to meet the basic needs of poor households. Market value of the wild edible plants was also reported by diferent authors at diferent parts of the country [41,42,45,46,51,60,61]. Among the recorded marketable plant species, seven were also reported to have the same role in Quara District [45] and six species with Chilga District [19]. Likewise, Balanites aegyptiaca, Tamarindus indica, and Ximenia americana in and around Awash National Park [46] and Syzygium guineense and Temarindus indica in Bule Hora District of Ethiopia [58] were also reported as marketable wild edible plant species. Generally, the diverse marketable wild plant species in the District could provide high cash income value beyond food if conservation priorities and emphasis are given.
Te multiple uses of wild edible plant species indicated the presence of rich indigenous knowledge within the community on plant species. However, their multiple uses might afect the species availability in the area. Similarly, Anbessa [58] and Dalle et al. [62] stated that the more the plant species used for multiple values, the more is their exploitation in the area. Hence, great attention should be given to the multipurpose wild edible plant species to maintain them for future generations. Apart from their food value, multiple roles of wild edible food plant species were also reported by other diferent studies [42,46,50,51,60,63]. Especially, in rural communities, wild trees and shrubs are the major sources of house construction and fuel wood. On the other hand, the local communities in the study area do not have a habit of planting trees. In addition, the great medicinal role of wild edible plants leads to their further depletion which was also reported elsewhere in Ethiopia [23,46,51]. Several plants with nutraceutical value are available in the study area which is also reported in other areas of the country [21].

Conclusions
Te result of the study revealed that Metema District supports several numbers of wild edible plants with their associated knowledge. Te District inhabitants meet their basic needs by consuming and marketing these plants. Since wild edible plants are easily afordable and accessible, the economically deprived segment of the community complements their diet by taking wild edible plants. Multiple roles of wild edible plants (food, medicine, fodder, construction, and fuel) resulted in their overexploitation. Tey are threatened by farmland expansion, forest clearing, over grading, and other destructive human activities. For sustainable utilization and conservation of these biological resources, migrants from highland areas and neighboring regions should be controlled. Strengthening farmers' traditional conservation practices such as growing wild edible plants in the homegardens and farmlands is the appropriate measure to bring these precious resources out of the grove. Moreover, awareness creation, value addition, and market linkage of high market potential wild edible plants would help to maximize income and improve the livelihoods of local people while contributing to sustainable forest management.

Data Availability
Most of the data used to support the fndings of this work are found in the supplementary materials. In addition, some of the data used for this work are included in the fgure fles (fgures and tables).