Influence of socio-demographic factors on medicinal plant knowledge among three selected ethnic groups in south-central Ethiopia.

BACKGROUND: The influence of socio-demographic variables was widely explored to evaluate their impact on indigenous and local ethnobotanical knowledge. However, the studies conducted in Ethiopia mainly focused on rural areas. They were limited to exploring and documenting ethnobotanical knowledge and the associated impacts of socio-demographic variables in rural-urban interface areas among ethnic groups. Hence, this study aimed to document plant-based indigenous and local ethnomedicinal knowledge and the associated impacts of socio-demographic variables among selected three ethnic groups in south-central Ethiopia. METHODS: Ethnobotanical data were collected using semi-structured interviews with 189 key informants, floristic species inventories, and field observations. Quantitative approaches were used to evaluate the use values (UV) of the most important medicinal plants, the informant consensus factor (ICF), fidelity level (FL), relative popularity level (RPL), and rank-order priority (ROP). Statistical tests were applied to evaluate the influences of socio-demographic factors and associations between variables on local ethnobotanical knowledge across ethnic groups in different informant categories. RESULTS: Statistical analysis revealed significant differences (p < 0.05) in the mean number of medicinal plants reported among age categories. There was also a positive association between the respondent's age and plant knowledge acquisition. Croton macrostachyus Hochst. ex Delile, Albizia gummifera C.A.Sm., Zingiber officinale Roscoe, Aloe macrocarpa Tod., Gymnanthemum amygdalinum (Delile) Sch.Bip., Calpurnia aurea (Aiton) Benth, and Allium sativum L. had the highest use values among ethnic groups. The highest informant consensus factor values were recorded for circulatory system disorders (0.68) followed by febrile illness and reproductive organ complications (0.66 each) across the three studied ethnic groups. The highest FL, RPL, and ROP values were noted for Lactuca inermis Forssk., Moringa stenopetala (Baker f.) Cufod., Withania somnifera (L.) Dunal, Allium sativum L., Citrus limon (L.) Osbeck, Ricinus communis L., Schinus molle L., Antiaris toxicaria (J.F.Gmel.) Lesch., Brucea antidysenterica J.F.Mill., Echinops kebericho Mesfin, Ocimum jamesii Sebald, Afrocarpus falcatus (Thunb.) C.N.Page, Searsia natalensis (Bernh. ex Krauss) F.A.Barkley, and Ricinus communis L. across ethnic groups in the study areas, which showed the conformity of knowledge on species curing potential and their prevalent uses. CONCLUSION: The study revealed that the ethnic groups of Gedeo, Oromo, and Sidama have considerable indigenous and local ethnobotanical knowledge practices. Statistical analysis shown high variation in the acquisition of local ethnobotanical knowledge among age groups, which boosted our understanding of the effects of socio-demographic factors on the local ethnobotanical knowledge dynamics. Thus, this finding advocates for efforts to repair the observed generation gap via continued professional support and educating local communities to preserve traditional knowledge and practices through systematic documentation.

Species-specific allometric models for reducing uncertainty in estimating above ground biomass at Moist Evergreen Afromontane Forest of Ethiopia.

An allometric equation is used to convert easily measured tree variables into biomass. However, limited species-specific biomass equations are available for native tree species grown in various biomes of Ethiopia. The available pantropic generic equation has resulted in biases owing to the uncertainty of the generic model estimation due to the difference in tree nature and response to growth conditions. The objective of the study is, thus, to develop a species-specific allometric equation for reducing uncertainty in biomass estimation at the Moist Evergreen Afromontane Forest in south-central Ethiopia. Five tree species were selected for model development, these selected trees were harvested and weighed in the field. The measured above-ground biomass data related to easily measured tree variables: diameter at stump height, diameter at breast height (dbh), crown diameter, and total tree height. The developed model evaluated and compared with previously published model by using measures of goodness of fit such as coefficient of determination (R2), total relative error, mean prediction error, root mean square error, and Akaike information criteria. The analysis showed that a model with dbh as a single predictor variable was selected as the best model for the estimation of above-ground biomass. It gives the highest R2 for Syzygium guineense (0.992) and the lowest for Bersama abyssinica (0.879). The additions of other tree variables did not improve the model The pantropic model by Brown overestimates the biomass by 9.6-77.8% while both Chave models resulted in an estimation error of 12-50.3%. Our findings indicated that species-specific allometric equations outperformed both site-specific and pantropic models in estimating above-ground biomass by giving 0.1% up to 7.9% estimation error for the respective tree species.

Ethnobotanical study on medicinal plant knowledge among three ethnic groups in peri-urban areas of south-central Ethiopia.

BACKGROUND: Documenting traditional knowledge on plant use among ethnic groups has enabled researchers to obtain a better understanding of how indigenous flora is seen and used in daily life. Their therapeutic applications will also encourage future conservation and phytochemical research, potentially leading to the development of novel drugs. However, past ethnobotanical studies conducted in Ethiopia mainly focused on rural areas, and limited coverage to document the ethnobotanical knowledge at the rural‒urban interface. Therefore, this study was conducted to document and analyze traditional ethnobotanical knowledge on medicinal plants among three selected ethnic groups in peri-urban areas of south-central Ethiopia. In addition, we attempted to investigate the range of cultural similarity and disparity between the studied ethnic groups in relation to traditional medicinal plants and diseases treated. METHODS: Data were collected using semistructured questionnaires and in-depth interviews of 189 key informants, floristic species inventories, and field observations. Several cultural importance indices and Rahman's similarity indices were applied to analyze the relevance of medicinal plants and cultural similarity among the ethnic groups. RESULTS: A total of 189 therapeutic plants representing 159 genera and 69 families were identified and documented across the three studied ethnic groups. Of these, the Sidama, Gedeo, and Oromo ethnic groups reported 28, 34, and 38%, respectively. Most medicinal plants were represented by herbs (36%), followed by shrubs (31%), trees (27%), and herbaceous climbers (7%). Rahman's similarity index (RSI) revealed considerable ethnobotanical knowledge variation among ethnic groups. Oromo and Sidama showed the highest disparity (63.8%), followed by Gedeo and Oromo (63.2%). Of the total collected therapeutic plants, 78 most important medicinal plants were selected for the cultural importance analysis, which revealed that Croton macrostachyus Hochst. ex Delile scored the highest point in the Gedeo and Oromo ethnic groups and Zingiber officinale Roscoe in the Sidama ethnic group. Whereas Cinnamomum verum J.Presl, Psidium guajava L., and Melia azedarach L. are the least. CONCLUSION: The present study revealed the presence of cultural differences in medicinal plant knowledge practices and therapeutic plant use among the studied ethnic groups in rural-urban interface areas of south-central Ethiopia. The diverse healing potential of plants would support future pharmacological investigations, emphasizing the need for adequate documentation of indigenous knowledge and versatile flora to prevent their further loss.

Determinants of carbon and nitrogen sequestration in multistrata agroforestry.

Agroforestry has the potential to sequester carbon (C) and nitrogen (N), thereby counteracting climate change and soil degradation. However, the lack of empirical quantitative evidence on determinants of C and N stocks hampers the management of these stocks. The aim of this study was to identify the key determinants of the C and N stocks in multistrata agroforestry. We sampled 81 plots with broad variation in 12 hypothetical determinants of C and N stocks aboveground and in two soil layers, located in three Ethiopian regions with varied multistrata agroforestry traditions and characteristics. Above-ground stocks were assessed using an allometric equation, and soil stocks were assessed with the fixed-depth method. The hypothetical determinants, i.e., the duration of agroforestry practice, the tree density, the proportion of plants with a high basal diameter, legumes and native species, the species diversity, the main crops, soil texture and pH, and altitude, were tested using linear mixed models. The duration of agroforestry, tree density, and proportion of plants with a high basal diameter (>25 cm) explained half of the variation in the soil C stock, which represented nearly three quarters or more of the total C stock. Duration and tree density explained most of the soil N stock, although legumes also influenced soil N. A high proportion of large legume trees reduced C/N, whereas a high proportion of large non-legume trees increased C/N. The aboveground C stock was explained by species diversity or the proportion of stems with a basal diameter >10 cm, depending on the main crop. There is a high potential to manage C and N stocks and their persistence, as well as soil productivity, by managing the duration of agroforestry, the density of large trees, the proportion of legumes, and the main crops in multistrata agroforestry.

Species diversity, composition, structure and management in agroforestry systems: the case of Kachabira district, Southern Ethiopia.

Agroforestry is increasingly being identified as an integrated land use enhancing plant diversity while reducing habitat loss and fragmentation. This paper examined species diversity, composition, structure and management in agroforestry systems. Two Kebeles (Kachabira and Mesafe) were purposively selected for this study. Then, farmers who dominantly practiced agroforestry practices such as home garden, parkland and live fence were stratified based on wealth categories. Ten percent of the sample households were randomly selected from each wealth category. Accordingly, a total of 83 households were selected. Inventories of plant species were done by sampling one plot of each farm management type. A total of 59 plant species, belonging to 56 genera and 36 families were recorded across the home gardens, parklands and live fences in the study area. Among the plant species, trees constituted 42%, shrubs 27%, herbs 29% and climber 2%. From recorded plant species, 66% were native and the remainders 34% were introduced species. From the native species recorded in this study, Lippia adoensis and Millettia ferruginea were endemic to Ethiopia. The mean Shannon diversity index of rich, medium and poor households in the three different agroforestry practices were 1.75, 1.57 and 1.62 in home garden, 0.36, 0.30 and 0.49 in parkland and 0.84, 0.99 and 1.00 in live fence respectively. The largest tree basal area was recorded in the live fence (14.7 m2ha-1), followed by home garden and parkland. The study revealed that agroforestry plays an important role in the conservation of biodiversity, and also by providing food, income and a wide range of other products such as fuel wood, construction material, fodder, spices and medicinal plants. Farm household landholding size, species preference and management found to be the most important influencing factors that affect the diversity of plant species. Further detailed study of explicit examining of the factors such as socio-ecological effects that determine species diversity and the contribution of different functional groups to livelihood is needed to fully understand the agroforestry system.

Allometric equations for estimating aboveground biomass of khat (Catha edulis)-stimulate grown in agroforestry of Raya Valley, Northern Ethiopia.

Khat plant (Catha edulis Forsk) is an evergreen perennial cash crop cultivated in east Africa, southwest Arabia, and Madagascar. The plant is known for its production of stimulant fresh leaves, and expanding as expense of other land uses for its short-term financial returns. We, therefore, developed allometric equations for estimating aboveground biomass and carbon (C) removal of khat grown in farmlands of Raya Valley, Northern Ethiopia. A total of 31 plant individuals were harvested destructively on the basis of their diameters and age ranges. The equations were parametrized using biometric variables such as basal diameter (d 10 ), diameter at breast height (d), dominate height (doh) and mean height (h). Results of the analysis showed that, stem accounted for 58%, branch 32% and foliage 10% of the aboveground biomass (AGB). Commercial foliage biomass C removal ranged from 2.3 to 2.7 Mg ha-1. The power equation, AGB = b 1 ×d 10 b2 ×doh b3 , was the best (highest ranked using goodness-of-fit statistics), explaining 96% of the variation in aboveground biomass (p < 0.01). Models comparisons showed that our best ranked equation (M6) improved the aboveground biomass estimate by 44% and 48 % that of generic and other species-site specific equations developed in the tropics, respectively. Thus, our best species-site specific equation developed in this study can accurately estimate aboveground of khat plant biomass in the study region.

Native forests but not agroforestry systems preserve arbuscular mycorrhizal fungal species richness in southern Ethiopia.

The rapid conversion of native forests to farmland in Ethiopia, the cradle of biodiversity, threatens the diversity of the arbuscular mycorrhizal fungi (AMF) pivotal to plant nutrition and carbon sequestration. This study aimed to investigate the impact of this land-use change on the AMF species composition and diversity in southern Ethiopia. Soil samples were collected from nine plots in each of three land-use types: native forest, agroforestry, and khat monocropping. The plots of the three land-use types were located adjacent to each other for each of the nine replicates. Three 10 × 10m subplots per plot were sampled. AMF spores were extracted from the soil samples, spore densities were determined, and species composition and diversity were evaluated through morphological analysis. Both spore density and species richness were statistically significantly higher in the native forest than in the agroforestry plots with no clear difference to khat, whereas the true diversity (exponential of Shannon-Wiener diversity index) did not differ among the three land-use types due to high evenness among the species in agroforestry. In total, 37 AMF morphotypes belonging to 12 genera in Glomeromycota were found, dominated by members of the genera Acaulospora and Glomus. The highest isolation frequency index (78%) was recorded for Acaulospora koskei from native forest. Consequently, the agroforestry system did not appear to aid in preserving the AMF species richness of native forests relative to perennial monocropping, such as khat cultivation. In contrast, the native forest areas can serve as in situ genetic reserves of mycorrhizal symbionts adapted to the local vegetative, edaphic, and microbial conditions.

Woody species composition, structure, and diversity of homegarden agroforestry systems in southern Tigray, Northern Ethiopia.

Nowadays, the conservation of biodiversity is a major environmental challenge globally. Homegarden agroforestry systems (HGAFs) have a large potential for biodiversity conservation. However, little attention has been given to the relative importance of HGAFs in terms of biodiversity conservation. The present study, therefore, aimed to estimate and compare the woody species diversity and structure of HGAFs and adjacent natural forest (NF) in Northern Ethiopia. Three sites were purposively selected based on the presence of HGAFs and NF adjacent to each other. A stratified sampling system was used to select representative homegardens from different wealth categories. In NF, a systematic transect sampling technique was employed. A total of 90 sample plots (10 m × 20 m) were used to collect vegetation data. A total of 32 species representing 26 genera and 20 families were identified from the studied HGAFs and NF. Thirty woody species belonging to 24 genera and 20 families were recorded in the HGAFs whereas, 11 species, belonging to 9 genera and 8 families were recorded in the NF. Native woody species accounted for 66% of all woody species recorded in both HGAFs and NF. Stem density, richness, and diversities of woody species were significantly higher in HGAFs than in NF (p ≤ 0.05). Trees and shrubs in the HGAFs had significantly lower stem diameters, height, and basal area than the adjacent NF (p ≤ 0.05). The results show that HGAFs complements the NF for biodiversity conservation and supports in counteracting the loss of woody species from the natural ecosystem. Hence, promoting HGAFs habitats in human-dominated landscapes should be part of the biodiversity conservation strategy.

Ethnobotanical study of medicinal plants used by indigenous people in and around Dirre Sheikh Hussein heritage site of South-eastern Ethiopia.

ETHNOPHARMACOLOGICAL RELEVANCE: The uses of medicinal plants have a long history and become important sources of the health cares in Ethiopia. These medicinal plants and their associated indigenous knowledge are being seriously depleted due to rapid change in environment and socioeconomic conditions of the country. However, as to the knowledge of the present researchers, limited studies have been done to identify these medicinal plants and to preserve the communities' indigenous knowledge on these plants. THE AIM OF THE STUDY: This study aimed at assessing and documenting traditional medicinal plant species, mode of preparation and delivery, and parts used in and around Dirre Sheikh Hussein heritage site of South-eastern Ethiopia. The study was also meant to explore related indigenous knowledge of the communities on the utilization of medicinal plants. MATERIAL AND METHODS: The data were collected using household survey, in-depth interviews of key informants, focus group discussion and field observation. The number of informants involved in the survey was 194 (one hundred ninety-four). RESULTS: A total of 87 medicinal plants belonging to 77 genera and 51 families were identified. These medicinal plants were comprised of shrubs (33%), trees (31%), herbs (29%) and climbers (7%). Of the total number of medicinal plants found out in the study, 43 were used to treat human diseases, 8 were used to cure animal diseases and 36 were used to treat both human and live stock ailments. Of the identified plant species, about 83% species were proved that they are commonly known and used elsewhere whereas, the uses of remainder ones are limited to the study area. Most of the medicinal plants (60%) were sourced from the forest and the rest were found from both the forest garden. The study also revealed that leaves were the most frequently mentioned (36%) plant part used in preparing remedies. Crushing (20%) and oral route of administration (59%) were commonly mentioned mode of preparation and administration, respectively The study also indicated that peoples' perception and cultural beliefs had significant influence on their preference of source of health care, whereas religion was found to have no association with the health seeking behavior. CONCLUSIONS: This study revealed that varieties of plant species are playing important role for treating different human and livestock diseases in the study area, and traditional healers have accumulated wealth indigenous knowledge on usage of plant medicine inherited through generation. Besides, the therapeutic use of the documented plants will provide basic data for further research that focus on pharmacological studies and the conservation of the most important medicinal plants.