Study of Use Patterns of Some Indispensable Wild Edible Plant Species Resources

1. Introduction

The importance of wild plants relates to their potential usage. Various traditional societies utilise different plant parts for food provisioning [1,2,3], and medicinal purposes [4,5]. Measurement of the “importance” of wild edible plants is termed “quantitative ethnobotany”, a crucial centralised concern to botanical studies [6]. Quantitative ethnobotany is explained as a field of study that came about as a response to the perceived subjectivity of descriptive approaches [7] used in plant diversity. Furthermore, quantitative ethnobotany must include studies that connect ethnobotanical information with floristic and phytosociological inventories. Subsequently, quantitative ethnobotany is defined as an area that includes studies that are designed to quantify local botanical knowledge using popular indices of relative or cultural importance [8,9].

Most importantly, quantification of the ethnobotanical knowledge is for the improvement of the livelihood of rural populations [10] and assisting with decision-making concerning plant use sustainability strategies [11]. Additionally, the understanding of patterns of wild edible plants use and their local cultural significance is important when setting priorities for the conservation and domestication of these plants [12]. It is also indispensable to evaluate the dependency and the households’ economic value of wild edible plant species [13].

Most outstandingly to accomplish any proposed priorities, the so-called cultural domain studies must be considered. The cultural domain is denoted as a group of elements or items that are categorized following culturally determined rules [12]. For example, plants can be organized as “medicinal plants” and/or “edible food”. Other researchers attest that many used indices tend to pull out specific uses cited by informants into what is termed “use categories” [14]. These use categories may include “construction”, “food”, “medicine”, “technology”, “firewood” and “others” [14]. Another significance of the use of cultural indices is to compare and test hypotheses concerning the “importance” of vegetation zones, plant families, or growth forms [15]. The significance of wild plants has been alluded to by many researchers [16,17]. Currently, global food supply and safety rely on insufficient agricultural products, whereas the agricultural sector is faced with a variety of challenges for maximum production. Although there are wild plants available for many different uses, less interest and attention are still afforded to their full utilisation. According to Sahoo et al. [17], neglected and underutilised wild plant resources remain the fundamental foundation of diversity in developing countries. Most disturbing, food insecurity is still one of the problematic issues troubling the world today [18].

Limited and superficial quantitative studies exist for wild edible plants in the Limpopo Province, South Africa. This has important implications for the livelihood sustainability of rural communities, preservation of indigenous knowledge, domestication of such plants, and environmental conservation efforts. The current study paid attention to the use patterns of wild edible plants in the Vhembe District Municipality in the Limpopo Province.

2. Materials and Methods

2.1. Sampling of Participants

Four remote villages from each of the four local municipalities, namely, Thulamela, Makhado, Musina, and Mutale were randomly selected between May 2018 and June 2020. Ten households were systematically sampled from each village by skipping ten households between samples. Ethnobotanical interviews were carried out with a total of 160 local people. Participants included 107 women and 53 men between the ages of 20 and 97. Furthermore, a total of 127 participants with more than six citations were selected and their documented information was considered for this research.

2.2. Study Area

The study was conducted in the Vhembe District Municipality of the Limpopo Province, South Africa. The district municipality covers about 2771 km² and has an average altitude of 400 m above sea level [19]. Vhembe District Municipality lies between 22°56´S and 30°28´E [20]. It is divided into four local municipalities namely Makhado, Mutale, Musina, and Thulamela (Figure 1). Local municipalities of the Vhembe District visited during this study receive rainfall ranging from 300 mm – 1000 mm [21] (Figure 1D).

2.3. General Vegetation Information

The nature of the climatic conditions in parts of Vhembe District Municipality supports a variety of vegetation types. The general vegetation of Vhembe district is classified as Mopani Bushveld. This vegetation type is characterized by Colophospermum mopane shrubs. In Makhado Local Municipality, there are two biomes namely: grassland and savanna [20]. Different vegetation types stretch through this municipality. Those vegetations include Granite Lowveld, Gravelotte Rocky Bushveld, Limpopo-Ridge Bushveld, Limpopo Sweet Bushveld, Makhado Sweet Bushveld, Musina Mopane Bushveld [22].

2.4. Data Collection and Analysis

For the sake of this study, the information collected from informants who managed to cite six and more wild edible plants was considered. Wild edible plant preferences of inhabitants of the four local municipalities of the Vhembe District were determined by checking the number of times plants and their different use categories were mentioned. Parameters considered in this case were plant growth forms (habits) and plant parts. Furthermore, to gain a better understanding of use patterns, the uses of different plant parts were divided into six categories (i.e., food [vegetables and fruits], medicine, construction, firewood, beverages, and others). The sixth category named ‘others’ includes ornamental, artifacts, and pastes. New uses of some plants were also recorded.

2.5. Market Surveys

Local markets around the three study areas, one in the Thohoyandou shopping complex, Lwamondo, and Levubu of the District were visited to capture a variety of wild edible plants sold and to record information on their market prices. Semi-structured interviews were conducted with vendors to capture information on the traded wild edible vegetables.

2.6. Statistical Analysis

Free lists were analysed at the local municipality level where the relative frequency of citations and use values were determined using Microsoft Excel. Student-test for independent by variables test was performed at p<0.05 using STATISTICA 13.2.

2.7. Ethical Considerations

Permission to engage with members of the community was requested and obtained from the tribal authorities of the four local municipalities. Furthermore, prior informed consent was obtained from members of the Vhembe communities who were available and willing to participate in the study. The sampling of informants was based on their availability and willingness to participate in interviews.

3. Results and Discussion

3.1. Profile of Wild Edible Plants Utilised

Eighty-seven species distributed in 34 botanical families were documented (Table 1). Of the 34 families, eleven species of the family Malvaceae were mentioned, followed by the Cucurbitaceae (8 species), Rubiaceae and Solanaceae (5 species each), Amaranthaceae, Apocynaceae, Fabaceae, and Urticaceae (4 species each). Anonnaceae, Asteraceae, Brassicaceae, and Myrtaceae had three species each whereas Anacardiaceae, Convolvulaceae. Loganiaceae, Olacaceae, Passifloraceae, Phyllanthaceae, Sapotaceae and Zygophyllaceae had two species each. Botanical families with only one plant species were Araceae, Boraginaceae, Cactaceae, Crysobalanaceae, Ebenaceae, Eurphorbiaceae, Meliaceae, Pedaliaceae, Polygonoceae, Rhamnaceae, Rosaceae, Salicaceae, Ulmaceae and Vitaceae (Figure 2).

The Malvaceae family consists of species that are popular for their mucilaginous substances [23]. Some of the Malvaceae species such as Corchorus tridens L. and Abelmoschus esculentus L. were mentioned by all participants of the current study. The unique reason for their consumption is due to their medicinal properties for constipation relief. Participants in this study highlighted the remarkable utilisation of fruits and leaves of Abelmoschus esculentus L. and Corchorus tridens L. respectively for the relief of constipation [4].

Cucurbitaceae is a large family of 800 species and 130 genera that have been used for their medicinal properties [24]. It was mentioned in the current study for the first time that leaves of Momordica foetida L. are sprinkled on food as a spice to relieve hangovers. Cucurbits are a good source of dietary fibers which provide healthy properties and help reduce levels of cholesterol [24]. Over and above, they show many biological activities such as antioxidant, antimicrobial, antidiabetic, anti-inflammatory, and anticancer [25]. The popularity of Cucurbitaceae has been attributed to the bitter taste that most of the plant species in this family possess, which is believed to provide medicinal value. The way in which plants taste, especially if bitter, may serve as a guide to potential pharmacological phytochemicals [26,27].

Further support for the role of taste in medicinal plant selection comes from the observation that species of Cucurbitaceae tend to be represented in traditional pharmacopeia [28]. These results agree with the results from the Vhembe which articulate the importance of taste towards plant species selection. Some species are used as potential traditional treatments for stomach and intestinal disorders. Lagenaria siceraria L. was mentioned to have medicinal properties against period pains. Noteworthy, the multiple roles of wild edible vegetables as both food and medicinal sources have been widely recognized by ethnic groups [29].

3.2. Growth Forms, Parts, and Use Categories of the Wild Edible Plant Species

Altogether, five different growth forms were mentioned (i.e., herbs, trees, shrubs, creepers, and climbers), tree plant species topped the other habits with an average frequency of citation of 291 followed by herbaceous species (229), climbers (68) creepers (46) and shrubs (19), (Figure 3). These findings are supported by studies of [30], also for the Vhembe area, and [31] for Ethiopia.

Most leafy parts (49%) of the wild edible taxa documented are utilised. Wild edible vegetables have played pivotal roles in daily lives as a relish diet for local inhabitants (Zhou et al. 2010). Additionally, leafy parts provide consumers with important nutrients such as vitamins and minerals needed for health maintenance [29]. Leafy parts were followed by fruits (47%), flowers (1%), tubers (1%), seeds (1%), and barks (1%). Roots and rhizoids are utilised by a few people in the Vhembe region (Figure 3). Most significantly, participants of the study area mentioned the use of flowers of Shashe (Sonchus asper), Murudi (Cleome gynandra), and Phuri (Cucurbita pepo) as edible parts (Figure 4).

Other indispensable information of wild edible plants that were mentioned only once or twice is outlined in Table 2. A total of 32 plant species belonging to 20 different botanical families was documented.

Furthermore, the different plant parts are categorized into six use categories with food (Vegetables and fruits) as the highest in the list. This was followed by the utilisation of some parts as medicine (30), construction (14), other (14), beverages (11), and firewood (8) (Figure 3). Leafy twigs for vegetables and fruits of wild edible plants are used abundantly for the preparation of different traditional cuisines as well as for the treatment of different ailments. The results of this study are consistent with Sutrisno et al. [3] because different plant parts are used as flavourants or condiments in many cuisines and as a traditional medicine to treat various ailments.

3.3. Preservation Ways of Wild Edible Plant Species

Preservation of vegetables for future use is practiced in the study area. The two preservation methods which are collect and dry and collect, cook and dry were used across the four local municipalities of the Vhembe District (Figure 5). However, the collect, cook, and dry method was highly preferred (Figure 5B). A general trend in the preservation methods throughout the district was noticed, and statistical results echoed these findings (Table 3).

Leaves of plants such as Phuri (Cucurbita pepo L. subsp. Pepo), Munawa (Vigna unguiculata L.), and Murudi (Cleome gynandra L.) are collected, cooked, placed on corrugated iron and sun-dried (Figure 6). This method allows the community to prevent food unavailability during dry seasons. The principal method of extending the shelf-life of indigenous vegetables through sun drying fresh or boiling in water before sun drying was articulated by other reports [32]. In addition to the utilization of corrugated iron as a podium for sun-drying vegetables, sacs of mielie meal are being used (Figure 6). It was also communicated that further drying processes for vegetables can be done on the reed’s baskets called “Luselo” in the Tshivenda language (Figure 6).

The same sun-drying method is not limited to vegetables, some fruits from wild edible fruit plants such as Lannea discolor (Munie), Vangueria infausta (Muzwilu), Diospyros mesipiliformis (Musuma) and Grewia villosa (Muphunzu) are preserved through sun drying. On the other hand, fruits of Hexalobus monopetalus (Muhuhuma) can be ground to a powder called Mugumo which can be used even when the fruits are out of season.

3.4. Socio-Economic Importance of Wild Edible Plants

3.4.1. Local Markets Survey

It is paramount to explore and understand the socioeconomic profile of the participants as a directive of influence on food preferences and dietary diversity. Biographical information of the participants attests that the majority are unemployed therefore for them to survive and attain nutritional needs they opt for wild edible trading and consumption. The monetary contribution to households’ livelihoods of interviewed vendors comes from government grants [33] and income from wild edible plant trading. A total of 14 plant species belonging to 8 taxonomic families were found at the visited local markets for commercialization purposes (Table 4). Commercialization of wild edible plants is gaining popularity because of some wild edible vegetables such as Cucurbita pepo L., Sonchus asper (L.) Hill subsp asper, Ipomoea batatas, Citrullus lanatus, Psidium guajava L., and Solanum retroflexum Dunal are also sold in grocery supermarkets. This notion provides hope that these plants can be sold in famous stores and more of them in grocery supermarkets as noticed from the findings of the research conducted by Sahoo et al. [17].

Most importantly, vendors attested to the significant and huge contribution of wild edible plants trading towards the vendors’ household income [34]. For some, the commercialisation of wild edible plants enhanced monetary contribution to household income to the insufficient government grant provisions. Wild edible plants’ selling income assists with other households’ needs such as purchasing electricity and protein-rich foodstuff to supplement the wild edible plants’ consumption. On the other hand, Sahoo et al. [17] articulated a noticeable business regarding the trading of vegetables and fruits of wild edible plants. Noteworthy, income generated from trading these plants can make a tremendous change for family monthly payments.

4. Conclusions

The findings of this study add value to the literature that the independency of wild edible plants clearly contributes to the improvement of the livelihoods of local communities. During this study, wild edible reliance in the enhancement of the livelihoods of the local communities of the Vhembe region was observed. However, in the context of the botanical families’ preferences, different attributes of plant species of Malvaceae become crucial to the well-being of individual local community members. Wild edible plants have been used in different ways over many generations and played pivotal roles in the provision of ethnomedicines as well as becoming a source of community reliance by maintaining food availability to rural households.

This study uncovered the use of flowers of Cleome gynandra, Cucurbita pepo, and Sonchus asper as edible parts that can be blended with leaves and fruits for local cuisines preparations. Despite the consumption of berries from Morus alba var alba, leaves can be boiled to serve as a relish to local communities. Therefore, there is a need for the development of wild edible cultivation strategies and contextualization of the relevant educational programme in achieving and promoting knowledge about income generation from wild edible trading. Local households’ income received through government grants is insufficient towards covering most of the local community households’ needs; however, wild edible plant cultivation education to locals which may result in good supplies for big supermarkets is a way forward to the enhancement of local communities’ income generation.