Assessment of plant diversity and utilization of wild medicinal species by households proximate to Arabuko Sokoke forest in kilifi county of Kenya

Abstract

Forests play fundamental roles in the provision of goods and services that are of utmost importance for the subsistence and commercial needs of the rural communities worldwide. However, there has been a reduction in the natural forest due to threats that are mainly attributed to anthropogenic activities. The advent of climate change is likely to worsen the situation. The pressure on forest resources is catalyzed by expansion of markets for forest products, agricultural expansion and infrastructural development. For instance, an upsurge in the number of herbal users in the urban and rural areas has increased the pressure on the forests, while modernization and changes in lifestyle have led to loss of traditional knowledge on utilization and conservation of forest resources. However, there is little empirical evidence on factors affecting knowledge and the status of the utilized and marketed plant resources from the forest. This study was therefore carried out in Arabuko Sokoke forest in Kilifi county of Kenya to determine plant species diversity, and their distribution in the disturbed and undisturbed areas of the forest; assess knowledge, utilization and contribution of medicinal plants to communities adjacent to the Arabuko Sokoke Forest. The study also analysed marketing channels for the traded herbal species and challenges in the trade. Plot and plotless techniques were used to gather ecological data on frequency, density, diversity and distribution of plants in the Arabuko Sokoke forest, whereas key informant interviews, focus group discussions and household interviews were used to gather information on ethnobotanical knowledge and household socioeconomic data. The highest plant species richness (78 species) and diversity (2.86±0.07) was recorded in the mixed community as compared to the brachystegia and cynometra communities. This was attributed to the favorable microclimatic and edaphic conditions in the mixed forest community. Species diversity was significantly (P<0.05) higher in the disturbed areas (2.55±0.06 in cynometra community and 2.86±0.07 in the mixed community) than in the undisturbed areas (2.25±0.07 in cynometra community and 2.51±0.07 in the mixed community). The results also showed community). The results also showed a higher number of woody plants with small diameter (4.0 to 33.9 cm), which depicts good generation recruitment in the forest. The results of the multiple regression model showed that age, use of herbal remedies, formal education of the household head and households‘ engagement in agriculture as the chief source of livelihood influenced the knowledge on medicinal plants. Anthropogenic factors such as charcoal production and commercialization of herbal products contributed considerable threat to medicinal plants. The results show that majority (71%) of households use plant medicine for treatment of the common diseases. In addition to scarcity of some forest species and poor market linkages, lack of proper processing and storage technologies, as well as value addition were mentioned as the key challenges in herbal medicine trade. The results also show that most of the traded plant products were obtained from the wild, and therefore pointing at the potential threat to the resource base in the absence of appropriate conservation strategy. From the results of this study, we recommend community awareness on sustainable forest utilization. The study further recommends the preservation of ethnobotanical knowledge through documentation and promotion of knowledge transmission to the youth. In addition, in situ conservation, domestication of the rare marketed wild medicinal plants and enhancement of market linkages is necessary to ensure maximum economic returns from herbal medicine trade. Keywords: Medicinal plants; Use values; Knowledge on medicinal plants; Species diversity; Trade of herbal products; Arabuko Sokoke forest