Quantitative Ethnobotany of Multiple-Use Species and Management of the Yangambi Biosphere Reserve in the Democratic Republic of the Congo

Abstract

The Yangambi Biosphere Reserve (YBR) in the Democratic Republic of Congo (DRC) faces significant challenges regarding the livelihoods of local communities and biodiversity conservation. The lack of scientific information on the spatial distribution of useful woody species hinders sustainable forest resource management and is a development constraint. This study was conducted in the villages of Yaselia, Lilanda, and Bagbanye on the outskirts of the protected area and aimed to identify the most useful woody species, analyze their socio-cultural value, assess their uses based on local community involvement, and evaluate their abundance beyond village forests to contribute to reforestation and conservation policies. An ethnobotanical survey of 105 households and a forest inventory of 9 ha were conducted to assess the abundance of 29 useful woody species. The results revealed that species such as Entandrophragma cylindricum (Sprague) Sprague and Hoyle, Petersianthus macrocarpus (P.Beauv.) Liben, Ricinodendron heudelotii (Baill.) Pierre ex Heckel, Scorodophloeus zenkeri Harms, Pentaclethra macrophylla Benth., Uapaca guineensis Müll.Arg., Blighia welwitschii (Hiern) Radlk., Chrysophyllum lacourtianum De Wild., Dacryodes edulis (G.Don) H.J.Lam, and Gilbertiodendron dewevrei (De Wild.) J.Léonard have high use and cultural value for local communities. The forest inventory showed that primary forests are better represented in terms of abundance and biomass of species with high use and cultural value, while fallow lands are less diverse and dominated by small-diameter trees. However, most of the useful species identified with high use and cultural value have low density/biomass or are absent in most of the plots in secondary forests and fallow land. These results underscore the urgent need to implement sustainable management strategies that include these species through traditional agroforestry projects. Such initiatives would enhance resource valorization, support local livelihoods, and reduce pressure on the YBR, contributing to the preservation of this biodiversity sanctuary and the promotion of sustainable forest management in the region.

Keywords: Yangambi Biosphere Reserve; biodiversity conservation; ethnobotanical survey; plant use value; quantitative ethnobotany.

FIGURE 1

Location of the villages Yaselia, Lilanda, and Bagbanye in the YBR landscape within Kisangani town and INERA concession Situation of this landscape in Tshopo Province and in DRC.

FIGURE 2

Forest inventory system applied in villages in the Yangambi landscape.

FIGURE 3

The relationship between the cultural value and use value of plant species in three villages within the Yangambi region: Yaselia (A), Bagbanye (B), and Lilanda (C). The cultural value of each species reflects its significance to local communities in terms of traditional practices, rituals, and social customs, while the use value indicates the frequency and range of practical uses the species has, such as food, medicine, construction, and other daily needs.

FIGURE 4

Abundance of plant species inventoried in the village farming areas of three villages: Yaselia, Lilanda, and Bagbanye, within the Yangambi region. The abundance of species is measured by the frequency and biomass of species found in each village's farming landscape, including habitats such as dense forest, secondary forest, and fallow lands.

FIGURE 5

Analysis of variance (ANOVA) comparing the biomass of plant species in three different habitat types: Dense forest, secondary forest, and fallow land in the villages of Lilanda, Yaselia, and Bagbanye, within the Yangambi Biosphere Reserve. The biomass data represent the total plant material (aboveground) per unit area in each habitat type. It highlights the significance of dense forests, the intermediate state of secondary forests, and the low biomass of fallow lands, reflecting the ecological status and anthropogenic pressures in the Yangambi region. * (p < 0.05): indicates statistical significance at the 5% level; ** (p < 0.01): indicates statistical significance at the 1% level; *** (p < 0.001): indicates very strong statistical significance at the 0.1% level; ns: indicates no significant differences.

FIGURE 6

The diameter structure (DBH—diameter at breast height) distribution of multipurpose species in dense forest, secondary forest, and fallow land. The diameter structure indicates the range of tree sizes present in each habitat, highlighting the distribution of different age classes and the presence of both small‐ and large‐diameter trees.

FIGURE 7

The fidelity level (FL) and abundance/biomass of the top 10 most used species in Yaselia village, categorized by their primary use type (food, medicine, construction, wood energy, craft, and commercial). Fidelity level (FL) is a measure of the species' degree of cultural significance, indicating how frequently a species is associated with a particular use category. This figure provides an overview of the relationship between the ecological availability of species and their cultural importance in the context of the village of Yaselia.

FIGURE 8

The fidelity level (FL) and abundance/biomass of the top 10 most used species by use category in the village of Lilanda. This figure clearly describes how the fidelity level (FL) and abundance/biomass interact to show both the cultural importance and ecological availability of plant species in Lilanda village, facilitating the understanding of the community's reliance on these species and their potential for sustainable management.

FIGURE 9

The relationship between fidelity level (FL) and abundance/biomass of the top ten most used species by use category in the village of Bagbanye. This combination of FL and abundance/biomass highlights species that are both essential to local needs and available in sufficient quantity, providing valuable insights for resource management, conservation, and sustainable use of these multi‐purpose species in the Yangambi region.