Traditional uses of wild and tended plants in maintaining ecosystem services in agricultural landscapes of the Eastern Cape Province in South Africa

Background Many communities in developing countries rely on ecosystem services (ESs) associated with wild and cultivated plant species. Plant resources provide numerous ESs and goods that support human well-being and survival. The aim of this study was to identify and characterize wild and tended plant species, and also investigate how local communities in the Eastern Cape Province in South Africa perceive ESs associated with plant resources. Methods The study was conducted in six local municipalities in the Eastern Cape Province, between March 2016 and September 2021. Data on socio-economic characteristics of the participants, useful plants harvested from the wild and managed in home gardens were documented by means of questionnaires, observation and guided field walks with 196 participants. The ESs were identified using a free listing technique. Results A total of 163 plant species were recorded which provided 26 cultural, regulating and provisioning ESs. Provisioning ESs were the most cited with at least 25 plant species contributing towards generation of cash income, food, traditional and ethnoveterinary medicines. Important species recorded in this study with relative frequency of citation (RFC) values > 0.3 included Alepidea amatymbica, Allium cepa, Aloe ferox, Artemisia afra, Brassica oleracea, Capsicum annuum, Cucurbita moschata, Hypoxis hemerocallidea, Opuntia ficus-indica, Spinacia oleracea, Vachellia karroo and Zea mays. Conclusion Results of this study highlight the importance of plant resources to the well-being of local communities in the Eastern Cape within the context of provision of essential direct and indirect ESs such as food, medicinal products, construction materials, fodder, regulating, supporting and cultural services. The ESs are the basis for subsistence livelihoods in rural areas, particularly in developing countries such as South Africa. Therefore, such body of knowledge can be used as baseline data for provision of local support for natural resource management initiatives in the province and other areas of the country.

. Research by Bidak et al. [2] showed that plant resources provide direct ESs such as serving as sources of food, medicines, energy and shelter. There are also indirect social and economic ESs derived from plant resources. Ecosystem services are classified into four categories: provisioning ESs such non-timber forest products, fibre, firewood, water, fish and natural medicines; regulating ESs such as pollination, natural hazards, water, air quality, runoff, disease and climate regulation; cultural services that provide recreational, aesthetic and spiritual benefits; and supporting ESs such as habitat for species, soil formation, photosynthesis and nutrient cycling [7]. Plant resources supply all three major categories of ESs, that is, provisioning, regulating and cultural services, including the supporting services that enable agricultural landscapes to be productive [8,9]. Plant resources provide ESs that extend beyond the provision of food, medicines, energy, shelter and some of these ESs are indirect, unmanaged, underappreciated and undervalued. For example, research by Ladino et al. [10] showed that the plant group Bromeliads provide direct benefits to the human society, and they also form microecosystems in which accumulated water and nutrients support the communities of aquatic and terrestrial species. Previous research by Calvet-Mir et al. [8] and Camps-Calvet et al. [9] showed that plants grown and managed in home gardens are important for the provision of cultural ESs. The authors argued that plant resources managed in home gardens offer nature-based solutions to environmental problems, protection and restoration of agricultural landscapes, promotion of healthy lifestyles, social integration and environmental justice. Similarly, Barrios et al. [11] argued that tree-mediated ESs are recognized as key features of more sustainable agroecosystems but the strategic management of tree attributes for ES provision is poorly understood. For example, Barrios et al. [11] opined that managing trees for ESs requires understanding tree identities, their characteristics, uses and how to manage these trees in the provision of all four ESs categories in different socio-ecological contexts. Despite their importance and everyday use, comprehensive knowledge of the ecology and socio-economic value of ESs derived from plant resources is largely lacking, hindering the ability to monitor, regulate and manage them. Therefore, a clear understanding about the condition of provisioning, regulating, cultural and supporting services provided by plant resources is necessary and such information is derived from both the resource use patterns of the people who are most reliant on these services, as well as the utility of the plant resources exploited by local communities.
Mensah et al. [3] argued that ESs underpin human livelihoods around the world as the use of ESs is important for decision-making processes that target the social expectations of local communities. However, a detailed understanding of the complex variation in the use and relative importance of ESs at the household level is required to fully understand how ESs affect livelihoods across different landscapes [12][13][14][15]. Other researchers are of the view that determination and identification of ESs is a prerequisite in order to estimate the relative importance of ESs in a community and ensuring their conservation and sustainable management [16][17][18]. Therefore, understanding the linkages between ESs and benefits for people is critical for safeguarding natural resources and particularly those important for groups that are most vulnerable to global change [19,20]. However, the ability of ESs to inform decision-making has been limited by knowledge gaps about the links between ES supply and the delivery and distribution of benefits [20][21][22][23][24][25]. Despite growing interest in ESs provided by plant biodiversity in different landscapes [26][27][28][29][30], few studies have attempted to systematically describe and evaluate the ESs derived from wild and tended plant species. Current statistics show that most ESs research has focused on higher income countries [31] while growing body of literature shows that there is direct dependence on ESs in low-income countries [32,33]. Therefore, the aim of this study was to assess ESs supplied by wild and tended plant species in the Eastern Cape Province in South Africa. The specific goals of this paper are: i. to identify and characterize the diversity of wild and tended plant species, and ii. to investigate how local communities in the Eastern Cape Province perceive ESs associated with plant resources.

Study area
This study was conducted in six local municipalities in the Eastern Cape Province in South Africa, namely Elundini, Mbhashe, Mbizana, Ntabankulu and Raymond Mhlaba and Umzimvubu (Fig. 1). The Eastern Cape Province is the second largest province in the country covering 168 966 km 2 of land area [34]. It is regarded as a rural province and is predominantly inhabited by isiXhosa speaking people of Cape Nguni descent. The Eastern Cape Province includes two of the former homeland areas, namely Ciskei and Transkei out of the thirteen former racially-defined homelands or Bantustan areas of South Africa [35]. One of the Apartheid government's acts of segregation was the Bantu Authorities Act of 1951, which legalized the deportation of Black people into designated homelands. Black people were forcibly removed from urban areas and white farms to those areas demarcated as homelands. The Ciskei and Transkei are today characterized by landlessness, pervasive chronic poverty, low levels of education, economic activity, vulnerability, lack of basic services, a dearth of employment opportunities and high levels of dependency on welfare [36,37]. An estimated 72% of the population in the Eastern Cape Province live below the poverty line, which is more than the national average of 60% and this is attributed to the legacies of Apartheid, where the Eastern Cape provincial administration inherited the largely impoverished and corrupt former Ciskei and Transkei homelands [38]. Research by Westaway [37] revealed that the majority of households in the Eastern Cape Province spend most of their income on food and there is clear evidence of growing food insecurity as measured by the number of meals consumed and the quantity and variety of foods eaten. Most people in the province live in rural areas, the contribution of agriculture to local livelihoods is low in the entire province and has been in decline for several decades [39]. Research by Shackleton et al. [40]  is between 0 and 1860 m above sea level, characterized by summer rainfall and dry frosty winters with approximately 500-1069 mm per year [42,43]. Mean maximum and minimum monthly temperatures are 38 °C in summer and 4 °C in winter, respectively [42][43][44]. The Eastern Cape Province is characterized by a variety of land uses ranging from commercially oriented rangeland stock farming to small-scale vegetable and crop production [42]. Other economic activities in the province include tourism, forestry and wool production [43]. Major crops cultivated in the study area include beetroot (Beta vulgaris L.), cabbage (Brassica oleracea L.), carrots (Daucas carota L.), maize (Zea mays L.), potatoes (Solanum tuberosum L.) and spinach (Spinacia oleracea L.). The majority of the inhabitants (at least 87%) in the study sites are traditional isiXhosa speaking people who are highly dependent on natural resources for their livelihoods [45].

Data collection
This study is part of a wider research on utilization of plant resources and other non-timber forest products in the Eastern Cape Province [46][47][48][49][50][51][52]. Therefore, sampling occurred during one week field excursions conducted between March 2016 and September 2021. Sampling was carried out in six Local Municipalities (Fig. 1). Standardized plant sampling procedures were used to collect specimens [53,54] involving transect walks in home gardens, farms and the surrounding landscapes. Interview  discussions were conducted in the local language, isiXhosa and were translated into English with the help of an interpreter. During the interviews, we documented information on names of plant species, uses, plant parts used and preparation of useful plants. The ESs were identified using a free listing technique [10,55], whereby interviewees were asked to list benefits and contributions of plant species to human well-being. The stated benefits were matched with the four major categories in the established ES classifications which included provisioning ESs (timber and firewood, edible plants, edible fruits and medicinal plants), regulating ESs (benefits from natural and ecological processes, e.g. pest control, pollination), supporting ES (healthy soil) and cultural ESs (tourism and recreation) [7,56]. These categories were expanded or modified based on information obtained during fieldwork, focus group discussions and field observations. Plant species were identified in the field and the taxon names conform to those of Germishuizen et al. [57] and the Plants of the World Online [58]. Unknown plant species were collected, pressed, oven-dried and identified by taxonomists at the Giffen Herbarium (UFH) at the University of Fort Hare and Schonland Herbarium (GRA) at Rhodes University, Grahamstown, South Africa. Ethnobotanical data were gathered from 196 purposively sampled participants using snowball sampling technique [59][60][61]. The participants were requested to sign University of Fort Hare (MAR011) informed consent form and researchers also adhered to the ethical guidelines of the International Society of Ethnobiology (www. ethno biolo gy. net). The majority of these participants (55.6%) were males and their age ranged from 18 to 84 years. More than half of the participants (57.7%) were above 50 years, while 34.2% were below 40 years of age. About half of the sample (46.4%) were single, 23.5% were married, 16.8% and 13.3% were widowed and divorced, respectively. Close to half of the sample (44.4%) were educated up to primary level, while 21.9% of the sample were educated up to secondary level, 17.9% and 15.8% of the sample had attained tertiary education or no formal education, respectively. About half of the participants (48.5%) were unemployed, surviving on government social grants and remittances.

Data analysis
The data collected were entered in Microsoft Excel 2016 file and this data were used to determine frequencies and other descriptive statistical patterns. Interview responses from participants were coded and sorted into themes, paying particular attention to inconsistencies and unique statements. The relative frequency of citation (RFC) of reported plant species was determined using the following equation: This index shows the local importance of each species and is given by the frequency of citation (FC) that is the number of informants mentioning the use of species divided by the total number of informants participating in the study [62,63]

Floristic composition
A total of 163 plant species were recorded in the Eastern Cape Province (Table 1), with herbs, shrubs and trees having the most species. Pteridophytes and gymnosperms were represented by a single species each, that is, Cheilanthes hirta Sw. (family Sinopteridaceae) and Podocarpus latifolius (Thunb.) R.Br. ex Mirb. (family Podocarpaceae), respectively. A large number of the plant species (67.5%, n = 110) recorded in this study are from 16 families ( Table 2). The other 29 families had less representation, between one and two species each. Plant families with the highest number of species were: Asteraceae (16 species), Poaceae (14), Fabaceae (10 species), Solanaceae (nine species), Amaryllidaceae (eight species), Asphodelaceae (seven species), Apiaceae (six species), Amaranthaceae, Asparagaceae, Cactaceae, Myrtaceae and Rosaceae (five species each), Apocynaceae, Lamiaceae and Myrtaceae (four species each) and Salicaceae (three species) ( Table 2). Bennett [64] categorized seven of these plant families, that is, Apiaceae, Fabaceae, Lamiaceae, Malvaceae, Myrtaceae, Poaceae and Solanaceae as vital for human existence. Bennett [64] also argued that diets of most cultures around the world rely substantially on species of Fabaceae and Poaceae families, and the world's three most important cultivated plants, that is, Oryza sativa L. (rice), Triticum aestivum L. (wheat) and Zea mays L. (maize) are grasses and belong to the Poaceae family. Similarly, Hammer and Khoshbakht [65] argued that Asteraceae, Fabaceae and Poaceae are among the most important families in the world as these families have high numbers of domesticated and semi-domesticated species. Among the recorded genera, those species belonging to Acacia Martius, Aloe L., Asparagus Tourn. ex L., Bulbine Wolf, Helichrysum Mill., Opuntia Mill., Prunus L., Solanum L. and Tulbaghia L. with three species each were the dominant taxa. From the 163 plant species recorded, 96 (58.9%) were indigenous to South Africa while 67 species (41.1%) were exotic (Table 1). Similar results were obtained by Akinnifesi et al. [66] who recorded 40.0% exotic plant species in home gardens of São Luis in Brazil arguing that such exotic species ensures biodiversity and genetic diversity. Other researchers argue that exotic species introduced purposefully offer economic and intrinsic benefits when used  as food plants [67][68][69], fuel [67,[70][71][72], herbal medicines [73][74][75], ornamental [76][77][78] and shelter [67,79,80]. Similarly, Kahane et al. [81] and Caballero-Serrano et al. [82] argued that indigenous and traditional plant species are usually less attractive to farmers and some commercial exotic species are preferred as these species are easier to grow and more marketable than indigenous and traditional food plants. Evaluation of plant diversity in home gardens of Kerala in India revealed that exotic plants constituted 51.0% of the recorded species [83].

Ecosystem services identification
A total of five cultural services (aesthetic, circumcision ritual, handicrafts, spiritual, social cohesion and integration), nine regulating services (air purification, animal enclosure, erosion control, green manure, insect control, live fencing, shading, windbreak and water purification) and 12 provisioning services (cash income, construction materials, culinary herbs, ethnoveterinary medicines, fibre, firewood, fodder, food, herbal medicines, leaf gel, thatching materials and wine production) were identified through interviews and observations made during field work (Fig. 2). Traditional male circumcision is an important cultural ritual practiced by the Xhosa people in the Eastern Cape Province. Male circumcision is carried out for cultural reasons, as an initiation ritual and a rite of passage or transition from boyhood to manhood [84][85][86]. The foreskin is cut off without anaesthesia and the wound is not stitched but bound in traditional medicines to help in the healing process [84][85][86]. The majority of species recorded in this study provided provisioning services such as herbal medicines ( (15 species, 9.2%), construction materials (12 species, 7.4%), firewood (11 species, 6.7%) and thatching materials (9 species, 5.5%) (Fig. 2). The cultural and regulating services were characterized by lower number of plant species than provisioning services. This result is consistent with previous studies that identified provision of food, medicinal products, construction materials, firewood, fibre and fodder as the most important ESs provided by wild and cultivated plant species [87][88][89][90]. Research by Landreth and Saito [91] showed that ESs derived from plant resources are diverse and subject to environmental, economic and cultural livelihood needs. Other researchers argued that food provisioning is particularly important in rural areas of subsistence economies as this ES is important for the well-being of households [92][93][94]. Similarly, a study by Mensah et al. [3] carried out in the Greater Letaba Municipality in the Mopani District of the Limpopo Province in South Africa revealed the dominance of the provisioning ESs such as edible plants, firewood and timber. A total of 30 medical conditions were treated using remedies prepared from medicinal plants (Table 1). Wounds, respiratory infections, skin diseases, stomach problems, cancer, diabetes, inflammation, headache and sexually transmitted infections (STI) were treated with the highest number of medicinal plant species (Fig. 3). Research by Ghuman et al. [95] showed that medicinal plants are widely used in South Africa for treating wounds, eczema, ringworm, sores, boils, pimples and infected wounds. Similarly, research by Louw et al. [96] showed that monocotyledonous geophytes and bulbous plants indigenous to South Africa are characterized by valuable pharmacological properties such as the analgesic, anticancer, antimutagenic, immune stimulating, antiinfective, antimalarial, cardiovascular and respiratory system effects. Results of this study showed that the value of medicinal plants in terms of number of species traded in the Eastern Cape Province is significant as 45.9% of the traded species were medicinal species in comparison with 54.1% food plants that were bartered with neighbours or sold in local markets (Table 1). Interviews with participants showed that the value of medicinal plants is not only for primary healthcare, but financial, cultural identity and livelihood security. Moreover, previous research by Van Wyk et al. [97] showed that medicinal plants are an important aspect of the daily lives of many people and an important part of the South African cultural heritage. The number of species used for regulating services ranged from one to four species. Species such as Aloe ferox Mill., Caesalpinia decapetala (Roth) Alson, Opuntia ficus-indica (L.) Mill. and Phragmites australis (Cav.) Steud. were used to reinforce animal and/or livestock enclosures. Agave americana L., Aloe ferox (Fig. 4) Figure 5 shows different plant parts utilized to provide various ESs. Whole or entire plants were associated with aesthetic plants, air purification, animal enclosures, erosion control, insect repellent, live fence, shading and windbreak (Fig. 5). Tree stems were used as firewood and water purification, while leaves were used as sources of culinary herbs, fibre, green manure, handcraft and leaf gel. Several plant parts were used as sources of herbal and ethnoveterinary medicines, food plants and cash income. However, harvesting of bark, bulbs, rhizomes, roots, stems and whole or entire plants, particularly herbaceous plants for medicinal purposes is not sustainable as such strategies threaten the survival of the same species used as food or to treat or manage human ailments or animal diseases. Important species recorded in this study with RFC values > 0.3 included Alepidea amatymbica Eckl. & Zeyh., Allium cepa L., Aloe ferox, Artemisia afra Jacq. ex Willd., Brassica oleracea L., Capsicum annuum L., Cucurbita moschata Duchesne ex Poir., Hypoxis hemerocallidea Fisch. Mey. & Ave-Lall., Opuntia ficus-indica, Spinacia oleracea L., Vachellia karroo (Hayne) Banfi & Glasso and Zea mays L. Allium cepa (onion), Brassica oleracea (cabbage), Capsicum annuum (pepper), Cucurbita moschata (butternut), Spinacia oleracea (spinach) and Zea mays (maize) were widely grown as food crops assisting in the provision of necessary nutrients and food security. Alepidea amatymbica and Hypoxis hemerocallidea are categorized as threatened in South Africa [99] due to over-collection as traditional medicines [46]. Other plant species that were recorded in this study that are categorized as threatened in South Africa include Boophone disticha (L. f.) Herb., Bowiea volubilis Harv. ex Hook. f. ssp. volubilis, Clivia miniata Regel, Gunnera perpensa L., Ilex mitis (L.) Radlk. and Prunus africana [88]. It is well recognized that medicinal plants primarily valued for their medicinal properties are intensively harvested and some of them tend to be the most threatened by over-exploitation.

Conclusion
Results of this study indicate that local communities in the Eastern Cape Province in South Africa derive ESs such as traditional medicines, food, raw materials, cultural and regulating benefits from plant species collected from the wild as well as cultivated species. This study showed that provisioning services were perceived as the most important ES in comparison with regulating and cultural services. These results highlight the importance of plant resources to the well-being of local communities in the context of provision of essential direct and indirect ESs such as food, medicinal products, construction materials, fodder, regulating, supporting and cultural services. The ESs are the basis for subsistence livelihoods  in rural areas, particularly in developing countries such as South Africa. Therefore, understanding the ESs that can be derived from wild and cultivated plant species is important, as well as the implications of utilization of such natural resources in the context of rural livelihoods and well-being. These ESs place plant resources in a web formed by linkages with different ESs services derived from agricultural landscapes. Therefore, these research findings contribute to the wider body of knowledge on ESs derived from plant species, expanding the understanding of the uses and values of plant resources, the livelihood benefits derived by local communities from plant species, and how these benefits influence local support for natural resource management initiatives in the province and other areas of the country.