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Evidence-Based Complementary and Alternative Medicine
Volume 2016, Article ID 5060247, 24 pages
http://dx.doi.org/10.1155/2016/5060247
Research Article

The Status of Ethnobotanical Knowledge of Medicinal Plants and the Impacts of Resettlement in Delanta, Northwestern Wello, Northern Ethiopia

1Department of Plant Biology & Biodiversity Management, College of Natural Sciences, National Herbarium, Addis Ababa University, P.O. Box 3434, Addis Ababa, Ethiopia
2Center for Environmental Sciences, College of Natural Sciences, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia

Received 3 October 2015; Accepted 22 November 2015

Academic Editor: Rahmatullah Qureshi

Copyright © 2016 Misganaw Meragiaw et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The present study was conducted in Delanta (Ethiopia) to examine the use of medicinal plants and investigate the impacts of the 1984/85 resettlement program on the local people’s knowledge on herbal medicine and its uses. The research was conducted with 72 informants in six study sites through semistructured interviews, group discussion, and market survey. In this study, 133 species belonging to 116 genera and 57 families were documented. These plants were mentioned for uses in the treatment of about 76 human and livestock ailments. The family Asteraceae was represented by the highest number with 14 species. Herbs accounted for 52.6% of the total species and leaves (32.6%) were the most frequently used parts. The analysis showed that the resettlement program has both positive and negative impacts on nature rehabilitation and local knowledge along with many human induced threats. Most of the plant knowledge is held by traditional healers and permanent residents. The people’s preference for some medicinal plants gave indications of continuity of the ethnomedicinal information among the inhabitants. The findings inform that efforts need to be directed to in situ conservation in two of the plant community types which could protect a good proportion (about 50%) of the medicinal plant species.

1. Introduction

The concept of ethnobotanical knowledge has originated from local people, which has the potential to redress some of the shortcomings of contemporary Western knowledge [1, 2]. It is passed down from generation to generation and closely interwoven with people’s cultural values [3]. Traditional societies throughout the world hold a wealth of such knowledge which they have built up during prolonged interactions with the natural world and which remains fundamental to their physical, spiritual, and social interests [4, 5]. While plants can provide multiple uses, the traditional curative practice of health problem is among the most important ones for peoples’ lives [68] and it is also one of the sources of modern health treatment [9]. Since time immemorial, traditional medicinal plants (TMPs) have been used in virtually all cultures for treatment of most human and livestock ailments [3, 10]. The uses of plant species as TMPs represent by far the biggest human use in terms of number of species of the natural world [11]. It is estimated that 70–80% of people worldwide [12] and 80% of the people of Ethiopia rely chiefly on traditional herbal medicines to meet their primary healthcare needs. The ways to combat diseases through TMPs are also as diverse as the different cultures [1315]. The natural plant world is thus full of potential for new drug discovery. There are undoubtedly many more secrets still hidden in the world of plants [16]. These resources are found in locally available plants and they benefit from local knowledge (LK) that is simple to use and affordable. Reasonable support for TMPs will not only help bridge some of the gaps between the demand for and supply of modern pharmaceuticals, but also widen healthcare alternatives for posterity [4, 15].

The most serious dilemma facing Delanta was recurrent droughts [17, 18] that often led to famines being usually accompanied by epidemics of different diseases [19]. Resettlement of local communities, acculturation, and inadequate understanding of the potentials of TMPs and the associated LK to the present and future generations have led to a decline in sustainable use of these biological resources [14, 20]. Natural and anthropogenic causes of wild vegetation loss and transformation of cultures further exacerbate the situation in most parts of Ethiopia including Delanta. Hence, promoting the cultures and the LK are vital for halting the loss, shaping and conserving the floristic diversity. Notably, attempts to respond to healthcare issues lead to ethnobotanical documentation on TMPs [9]. However, as the ethnobotanical information is not documented and remains in the memory of elderly practitioners and end users, the knowledge base continues to be threatened [21, 22]. Adequate information on the TMPs of Ethiopia could only be obtained when studies are undertaken in the various parts of the country where no ethnobotanical explorations have been made [23].

Maintenance of the balance between conservation and human needs has always been a complex matter. Environmental resettlement programs have been positive with respect to alleviating the problems of recurrent food insecurity and enhance restoration of useful wild plants in the original places from where people were moved out. This, however, requires careful evaluation of people’s attitudes and perceptions of LK [24, 25]. Resettlement took place in Delanta at different times [17, 18, 26, 27] and the resettlement is still continuing. More floras, however, were lost by drought, further aggravated by returning of thousands of resettlers; recovery efforts have been even more difficult [19]. As a plant species is lost from a locality, the information contained in it will also be slowly blurred and finally become lost forever. Urgent ethnobotanical studies and subsequent conservation measures are, therefore, required to salvage these resources from further loss. Thus, the main objective of this study was to document the availability of plants which have been used as remedy to combat ailments and the LK on use of these resources together with the impacts of the 1984/85 resettlement as so far no such study has been conducted in Delanta.

2. Material and Methods

2.1. Description of the Study Area and Climate

Delanta district is located at 530 km north of Addis Ababa in northwestern Wello. The major town, Wegeltena, is situated at 11°35′N latitude and 39°13′E longitude with an elevation of 2555 m (Figure 1). The district has an estimated total population of 128, 416 with an area of 1060.17 square kilometers. The largest ethnic group is the Amhara (99.96%) and Amharic is spoken as a first language [[28], Delanta District Agricultural and Rural Development Office, unpublished annual report of 2011]. The Health Centre of Delanta District has eight health stations and 32 health posts. However, access to modern health services is very limited in both personnel and equipment availability. Therefore, as Abebe et al. [13] indicated, a better alternative for the majority is to use the traditional herbal remedies. The statistical data of the Delanta District Health Centre [unpublished annual report of 2011] shows that, among 20 types of diseases, the most frequently occurring are helminthiasis, lower and upper respiratory tract infections (LRTI and URTI), and arthritis.

Figure 1: Map of Ethiopia showing the location of Delanta district and the study sites.

The study area receives bimodal rainfall. The major peak is important for crop production when the annual rainfall is received from mid-June to the beginning of September. The climadiagram in Figure 2 illustrates that mean annual rainfall and the temperature are 590 mm and 13.2°C, respectively. As the climadiagram and some authors [14, 29] indicate, the natural vegetation of the study area largely falls under the dry ever green montane forest occurring in the altitudinal ranges of 1,500 to 3,200 m. However, the intense deforestation of the highlands led to massive loss of forest cover. One of the main contributing factors to the weakness of environmental protection and its proneness to drought and famine has been the deterioration of the natural vegetation.

Figure 2: Climadiagram of the study area from the years 1999 to 2010 (data source: National Meteorological Service Agency of Ethiopia, Kombolicha Branch Directorate, 2011).

The district is divided into four agroecological zones. Farmers depend on both BELG and MEHER rainfall. Although these two production systems vary in source of income along with elevation, crop production is the largest source of income, followed by livestock and off-farm sources in the district [18, 28]. With regard to geology of Delanta, very stable and excellent qualities of Ethiopian opals are found in a specific alternating layer of basalt and rhyolitic ignimbrite thick volcanic series [30]. However, fatal accidents and loss of biodiversity (wild useful plants) caused by collapsing rocks or falls from cliffs have been reported and observed. Thus, the important solution to balance the mining benefits and the loss of biodiversity could be replantation of trees in the mine areas.

2.2. Ethnobotanical Methodology

Ethnobotanical information on the traditional use and management of TMPs was collected through participatory rural appraisal involving semistructured interviews and focus group discussions. All the discussions and interviews were conducted in Amharic language. The impact of the 1984/85 resettlement on vegetation rehabilitation was examined with guided field walk. Market survey was integral part of this research. Purposive sampling method was used and six representative sites (kebeles) (kebeles are the smallest administrative division next to district) consisting of 38 villages were selected within the district. Most of the sites were in the middle agroecological zones of the eastern part where the 1984/85 famine was especially worse [18, 26]. In total, 72 informants aged 20 to 88 years (55 males and 17 females) were selected, of whom 18 key informants were selected by purposive sampling based on recommendations of elders and local authorities from every six study sites with equal numbers.

Plant specimens were collected with local names and GPS data, pressed, dried, and brought to the National Herbarium (ETH), Addis Ababa University, for final determinations and confirmation using taxonomic keys in the flora of Ethiopia and Eritrea, comparison with authentic specimens, and expert assistance. The voucher specimens with labels were then deposited at the ETH. The vegetation of the study area was described using both the emic and etic categorization methods. The dominant or associated codominant species gave etic plant community types and the emic categories followed Martin’s system of emic vegetation classification [1], which relied on the way the people perceived plants and gave names in Amharic language.

The collected data were analyzed using descriptive statistics to evaluate the percentage and frequency of different aspects of TMPs. Preference ranking was conducted by using nine randomly selected key informants to rank five TMPs’ use against febrile illness and the degree of scarcity of other five TMP species. In paired comparison, nine key informants were asked to choose the top five TMPs used to treat stomachache based on their medicinal values. The number of pairs for each was calculated by applying the formula: , where is the number of items. The total number of items was obtained by summing up the total scores obtained. Direct matrix ranking was used to compare seven multipurpose TMPs and six principal threats using nine key informants following Cotton [5]. Informant consensus factors were calculated for each ailment category to identify the agreements of informants on the reported cures using the following relationship: , where Nur is the number of use reports from informants for a particular plant use category and Nt is the number of taxa that are used for plant use category for all informants. Eight categories were identified based on local explanation. ICF value ranges from 0 to 1. Abundance score was conducted to reflect the trends of indicator species in homegardens and wild vegetation during periods from the 1970s to 2011. The informants were asked to score the availability of an indicator species of TMPs. The scores ranged from 0 to 2 where 0 reflected none or nearly none; 1 a few or some; 2 many or readily available following Nanyunja [20].

3. Results

3.1. Diversity and Growth Habits of TMPs

In total, 133 TMP species (including two vascular seedless plant taxa) distributed into 116 genera and 57 families were documented. Those species were collected from different habitats, notably wild vegetation that could be enclosed and unenclosed, farmlands, and homegardens. The growth form analysis of total TMPs indicated that the most widely used plant remedies are obtained from herbs (71 species, 53.4%), followed by shrubs (48 species, 36.1%) and trees (14 species, 10.5%). Of the total 57 families, Asteraceae and Lamiaceae were found to be represented by the highest number of species (14 and 12, resp.), followed by Euphorbiaceae and Solanaceae with eight species each. Three families had four to five species, another five families had three species each, 16 families had two species each, and the remaining 29 families were represented by one species each (see Appendix   in Supplementary Material available online at http://dx.doi.org/10.1155/2016/5060247).

TMPs Used for Treating Human and Livestock Ailments. Of the reported 133 TMP species, 82 (61.7%) species representing 72 genera and 44 families were reported as medicine for treating human ailments (Figure 3). Generally, all the TMPs were used for the treatment of about 76 ailments of human and livestock (Table 1).

Table 1: TMPs used against human and livestock ailments and detailed information on methods of preparation. Description of data: Uf.: used for (L: livestock; H: human; Hl.: both), Cp.: condition of preparation (F: fresh; D: dried; and Fd.: fresh & dried), Ra.: route of administration (D: dermal, Op.: optical, N: nasal, O: oral, A: anal, and V: vaginal), and Pu.: plant parts used (R: root, S: stem, Sb.: stem bark, Rh.: rhizome, L: leaf, F: fruit, Fl.: flower, Se.: seed, B: bulbs, La.: latex, W: whole parts, and Ag.: abovegroufnd part).
Figure 3: Proportion of treatment of human, livestock, and both human and livestock ailments.

With regard to plant parts, leaves were the most frequently used parts (32.6%) used to treat various ailments, followed by roots (21.7%), and further details are given in Table 2. Most frequently used preparation methods of TMPs in the area are chopping, crushing, and pounding, which account for the highest proportion (38.3%), followed by grinding in powder form (20.0%); roasting, boiling, and cooking (11.3%); rubbing and unprocessing (11.3%); squeezing (10.8%); and chewing and absorbing (8.3%). Once herbal medicaments were prepared, dosages were estimated using different locally available materials. Doses of liquid remedies were estimated by using plastic cups or glasses (could be coffee-cup, tea-cup, or water-cup) or gourd utensils, lid of rubber, or number of drops. Spoons (teaspoon) for powders, counting numbers for seeds and fruits, and index finger size for roots are some of the traditional tools of estimation.

Table 2: Frequency of plant parts used and route of administration of remedy from TMPs.

After estimating the doses, different routes of administration were used. Oral route (43.9%) was being the most common route of administration, followed by dermal route (28.7%) as shown in Table 2.

In Delanta, no side effects were reported by informants except some species like Calotropis procera, Euphorbia spp., and Lobelia rhynchopetalum. The white latex of these species was used for treating different ailments, which was reported as noxious for humans if not properly handled. Hagenia abyssinica and Silene macrosolen were said to result in vomiting and diarrhea and if the risk is diagnosed, patients were given SHIRO WOT (sauce made of pulse grains) and powder of Linum usitatissimum infusion in water to reduce the pain. Cucumis ficifolius and Phytolacca dodecandra were said to have similar counter indications unless proper care is taken in dosage determination. Milk products, salt, honey, coffee, traditional ale, food, and water are some additives used by healers when preparing remedies to improve the taste and ointments of remedies. Most of the plant remedies were employed in fresh forms (54.4%) followed by dried (26.5%) and both fresh and dried forms (19.1%). The local people stored dried remedies for future use only for some diseases. The majority of prepared remedies were applied through eating, sucking, decanting, and inhaling (internal application, 67%), followed by creaming and tying (external application, 33%).

Consensus on Use, Popularity, and Importance of TMPs. The top ten TMPs were known by more than one-fourth of the informants. Ocimum lamiifolium is the most popular, cited by 66 informants (91.7%) for its medicinal value, followed by Zehneria scabra with 61 (84.7%), and others are given in Table 3.

Table 3: Informant consensus on commonly known TMP species.

Febrile illness was the third common disease of both human and livestock in the district health office. Preference ranking of five TMPs was reported as effective for treating febrile illness. Table 4 shows that Ocimum lamiifolium and Zehneria scabra came in the first and second ranks.

Table 4: Preference ranking of TMPs against febrile illness.

Paired comparison was made among five TMPs that were identified by the informants to be used in treating stomachache (Table 5), which was the 2nd common human disease according to data from the district health office. The results showed that Schinus molle and Verbena officinalis ranked first and second.

Table 5: Results of paired comparison for five TMPs used for treating stomachache.

Informant Consensus Factor (ICF). Diseases that were found to be prevalent in the area were treated by a variety of TMPs. The highest ICF value (0.91) has been shown from the categories of respiratory disease, febrile illness, and throat infection with relatively smaller number of species (19) used by a large proportion of the healers, followed by disease related to internal parasites and gastrointestinal disorders with ICF value of 0.82, represented by the highest number of both species (46) and informants (248). On the other hand, the category of genitourinary problems was only treated by healers, which had the lowest ICF value of 0.43 with five species (Table 6).

Table 6: Informant consensus factor for the given disease category.

Marketable TMPs in Delanta District. Market survey was conducted at Tirtria and Adagua in the major town. Some herbal medicinal plants were recorded based on direct observation and interviewing traders, vendors, and consumers. They reported that most of the herbal medicines were sold and bought for various use values such as spices, condiments, foods and beverages, fumigants, and cultural and spiritual aspects. These species included Allium cepa, A. sativum, Capsicum annuum, Myrtus communis, Rhamnus prinoides, Cucurbita pepo, Olea europaea ssp. cuspidata, Otostegia integrifolia, Ruta chalepensis, Vicia faba, and Zingiber officinale.

Multiple Uses and Ranking of Ethnomedicinal Plant Species. Some of the TMPs in the study area were used for other purposes. Multiple use analysis showed that firewood and charcoal are the most frequently mentioned uses (27.3%) while the wild (normal and famine) food category was the least reported (10.0%) (Figure 4).

Figure 4: Proportion of other uses of the ethnomedicinal plant species.

Use diversity analysis shows that, among the six TMPs, Carissa spinarum is ranked 1st, followed by Rhus vulgaris ssp. neoglutinosa, and the others are given in Table 7.

Table 7: Results of direct matrix ranking of multipurpose TMPs.

Threats to and Conservation Status of TMPs. The threats resulted mainly from human activities and they varied from site to site. Among these activities, agricultural land expansion is ranked 1st, followed by fuel wood and construction material collection, overgrazing, mining opal, and drought (Table 8).

Table 8: Results of direct matrix ranking of factors threatening to TMPs.

Further analysis showed that Withania somnifera came out in the first rank of most threatened TMP (Table 9).

Table 9: Priority ranking values (based on their degree of scarcity in the wild) for five selected TMPs.

Trends in Abundance of TMP Species. The degree of abundance of TMP species considering their current status was reported as 50 common species, followed by rare (45 species) and sparsely distributed species (40), based on informants’ perception and direct field observation in the wild state. Figure 5 shows that the homegarden is maintained in an increasing state of some of the indicator TMP species, particularly those said to have been lost from the wild environment in the 1970s, and then went on decreasing.

Figure 5: Trends of ethnomedicinal plant species in homegarden and wild vegetation.

Local Ecological Knowledge of People. In the study area, people have knowledge about their environment (landscapes, vegetation, and soil types). Based on topography of the land forms and the color and fertility of soils, they classified the ecological units into six categories in Amharic language based on their lifelong LK. This is presented along with the etic categories in Table 10.

Table 10: LK of people on landscapes and soil types.

The LK of People on Plant Community Type and Distribution of TMPs. Although natural forests have disappeared in many places due to many reasons, the vegetation of the study area still keeps relatively high number of species of TMPs. However, among 19, six endemic plant taxa in the floristic region of Ethiopia and Eritrea were not recorded as they are found in the floristic region of Wello (WU). These are Urtica simensis, Impatiens rothii, Aloe pulcherrima, Solanum marginatum, Lobelia rhynchopetalum, and Primula verticillata ssp. simensis. The plant community types were identified through categorization of the local people (emic classification approach) and observation of the researcher (using etic classification) based on the dominant plant species as visually inspected. Eight major community types were recognized. All types of plant community types are found in six study sites except Lobelia rhynchopetalum and Euryops pinifolius dominated community type, which is restricted in one of the study sites, namely, Tikshign Sinat kebele between 3539 to 3702 m a.s.l. Some of the following species are not included in the present paper, but they are collected and preserved in ETH by the authors for other purposes (Table 11).

Table 11: Plant community types and characteristic plant species.

The present study noted that well-organized emic classification of local vegetation was not shown in some ecological settings (largely DEGA zones) where natural vegetation has been almost completely changed into agricultural lands. Regarding habitat, most of the TMPs are distributed in different habitats though their availability varies from place to place among species. The majority were harvested from the wild (71 species), followed by homegarden (24 species), and cultivated in farmlands (Figure 6). The wild vegetation could be either enclosed (protected by government or private sectors) or unenclosed, which is open to all people.

Figure 6: Proportion of habitat diversity of TMPs.
3.2. Comparisons of LK among Age Groups and Its Transfer System

The LK of the three age groups was compared with respect to the names and the respective uses of TMPs. The sample sizes of each age group were 14, 28, and 30 persons from 20 to 88 with 22 years’ gap. The results show that the age groups within the ranges of 66–88 years reported the highest proportion of TMP names and uses. The total value is more than 100% because sometimes same plant species were mentioned by all groups (Figure 7).

Figure 7: Variations of LK in TMPs among the three age groups of informants.

The majority of traditional healers (84.4%) kept the knowledge with them and selected family members for the sake of confidentiality while others (16.6%) transferred their LK to other persons (Table 12).

Table 12: Mode of TMP knowledge transfer from traditional healers to others.

Consequences of Resettlement on Environmental Component and LK of TMPs. The study reported that half of the interviewed informants were those that returned from the destination area due to the 1984/85 resettlement. This indicated that the 1984/85 drought was one of the worst disasters in the area. In case of returnees, 17 plant species have no names and some of the names given also were more general (e.g., HAREG refers to any climber plant). However, this is not seen in traditional healers who have used “medicoreligious manuscripts.” In case of resident people, however, some of the TMPs are named by using the disease treated adding YE at the beginning followed by MEDANIT. For example, three species (Cistanche tubulosa, Polygala abyssinica, and Vernonia schimperi) are named as YESATMEDANIT, YEBABMEDANIT, and YEMICHMEDANIT, to say medicine of burns, snake bite, and febrile, respectively. It is noted in Table 13 that permanent inhabitants have complete names for each except two species (Ekebergia capensis and Pulicaria schimperi), which is not the case for the remaining groups of informants.

Table 13: Variation of LK on some TMP names.

Of 36 returnees including some key informants, only two persons were born in the destination of resettlement areas and the rest were primarily born in the original area and then left from their original area during the 1984/85 famine. However, after staying away at different times, they came back to their original location (Delanta district). The sample sizes of the three groups of informants were 18 key informants, 25 permanent residents, and 29 returnees. The results showed that key informants are more knowledgeable about TMP species (92.6%), followed by permanent residents (81.5%). However, concerning returnees, the least results were recorded in all the three aspects (Figure 8).

Figure 8: Variations of LK of TMPs among three groups of informants.

The findings on the impacts of resettlement depict that the 1984/85 resettlement had both positive and negative results in the area of ethnobotanical knowledge and social and cultural activities. From negative perspective, for instance, majority of the returnees had lost specified local names and detailed preparation of TMPs, and youngsters were not willing to respect the LK and the associated taboos. For the positive perspectives, on the other hand, the former farmlands were converted into noncultivated vegetation. Such promoting ecological rehabilitation in turn provided restoration of wild useful plants and reduced human pressure on plant resources.

4. Discussion

Relatively high number of TMP species is encouraging and a good indication that the area has reasonable number of useful plant species. This is partly the result of the action to move out drought-affected people from the area and the fact that the permanent residents went on using and protecting the plants. The results agree very well with the findings in the Cheffa plain of southern Wello where 83 TMPs species were recorded [31]. Although there is continued deforestation and degradation in the area, the remaining species and the taxonomic diversity (59 families) promise success in conservation. As in other studies made in southwestern Ethiopia [22] and elsewhere [8], the family Asteraceae came up with high number of species. Asteraceae is also the second (next to Fabaceae) largest represented dicotyledonous family in the flora of Ethiopia and Eritrea with 440 spp. The results of this study prove that people tend to use preferably the plants that are easily available to them excluding, of course, those that are toxic or lethal. As was affirmed by other studies [8], the more common the plant species is in an area, the greater the probability of its popular use is. The study showed that the wild vegetation is the major habitat where a significant proportion of TMPs are harvested. The distributions of all, but two (IV and V), of the plant community types also confirmed this habitat. This result is in agreement with different studies carried out elsewhere in Ethiopia [7, 23] and other parts of the world [11].

The people of Delanta rely largely on herbs, which are replacing the forest resources and are relatively common in the areas where extensive degradation has taken place. This finding agrees with findings of many authors [12, 21, 32] but disagrees with other studies [31, 33]. This could be related to the level of agricultural expansion and perhaps due to the presence of two rain-fed seasons. In most cases, there are several plant species used in combination to treat specific ailments, which was considered important to increase the strength and effectiveness of the remedies. Such practice was also common in other countries [34]. According to Abebe and Ayehu [6], the use of several species for the treatment of a particular ailment could indicate the prevalence of the species. The common use of leaf for preparation of remedies could partly be due to the relative ease of finding and simplicity of preparation. Leaves were shown to be the most commonly utilized parts in other findings [12, 22, 31]. Contrary to this finding, Hunde et al. [33] reported that roots were the most widely used parts, and this may be related to the medical culture of the people and environmental condition of the area. Moreover, collecting leaf parts for medicinal purpose is usually not a threat to the survival of plants as compared to the use of whole parts, roots, and stem barks [6, 35].

Among several preparation methods, the most frequent use of chopping, crushing, and pounding could be because of ease of use of local tools. Similar finding was reported by Tamene et al. [31] but deviates from other findings [12]. Informants underlined that attention is given in determination of dosage and depends on experience of traditional healers, age of patients, and the power of TMPs. They also had relatively better measurements for humans than livestock. However, lack of precision and standardization in measurement is considered as the general weakness of traditional healthcare system [4, 32]. The findings showed that most remedies in Delanta were administered orally in agreement with other reports from northern Ethiopia [6, 31, 32]. The fact is that modern health system also reported that there was high prevalence of internal problems and gastrointestine disorder in the study area. This also emerged from the calculations of ICF values. However, Giday et al. [22] indicated that skin (dermal) was the predominant route of administration. Most remedies were prepared and used immediately after harvest. As traditional healers pointed out, the use of either fresh or dry form is based on the type of applications and the availability of TMPs. Herbal drugs were mostly applied internally (58.3%) and the plants were found around homegardens. Fresh forms were favored since this form is considered to be strong and healthy. The wider use of fresh conditions was also reported from elsewhere [22, 35].

In the community, some of the TMP species were more popular and recognized as more effective and popular remedies than others. From both rankings and comparisons, it could be understood that the most favored species are usually the most effective ones for being used against a particular ailment. Thus, the preferences of some TMPs more than others prove the reliability and continuity of the ethnomedicinal information obtained from the local people. Among eight identified disease categories in the area, respiratory diseases, febrile illness and throat problems, and internal parasites and gastrointestine disorders were the most frequently encountered with high value of ICF. This may indicate high incidence of these types of disease in the area, possibly due to the poor socioeconomic and sanitary conditions of the people perhaps related to drinking stream water and food preparation. This finding is in line with another study conducted in northwestern Ethiopia [32]. Heinrich [36] also indicated that TMPs that are believed to be effective in treating a certain disease have higher ICF values whereas a low value implies that the informants disagree on the taxa. All these signified that people rely chiefly on TMPs to meet their primary healthcare needs and this holds true in other previous studies [6, 12]. Some of the species discussed herein (Table 1) were also incorporated in modern pharmacological remedies with the same treatment and parts used by other researchers [3739]. These are good indicators that the present study will serve as an input for further works in modern therapeutics activity.

With this study, informants noted that resettlement program contributed to biodiversity conservation in the original place as evidence of the TMPs that are regenerating in the wild vegetation and former farmlands since the local people left Delanta. This was mainly seen in the lowlands (1700–2600 m a.s.l.) of the study area that was hard hit by the 1984/85 drought as described by Rahmato [26]. Inappropriateness for farming is also served as reinforcement for the areas that have been shifted to restoration and unsettled lands. Other findings were reported by different authors elsewhere in Ethiopia [25, 40, 41] also affirmed that the basic rationale behind resettlement was to facilitate resource rehabilitation and to provide poor households with a better livelihood. According to Dhakal et al. [24], however, it needs careful evaluation of peoples’ perceptions on volunteerism to handle with proper management of biodiversity.

Although many positive outcomes were seen in the recovery of habitats, there was some loss of LK and culture of resettled people after resettlement. Such mixed results were also shown in another study [24]. Informants reported that before the 1984/85 resettlement people’s judgments on their conservation outcomes of vegetation which foster TMPs were very positive. With regard to returnees, however, this habit has been reducing so that resettlement (staying away from the original site) could be one of the reasons. Traditional healers who might not have gotten opportunities to come back to their original place may have lost some of the LK to treat ailments such as asthma and tuberculosis (lung problem) in the local people was mentioned. This was again another barrier in transfer of knowledge to the young generation. This resulted in the loss of specified local names of some plants and their uses. According to some key informants, some TMP species were lost by improper exploitation of root parts which was aggravated by drought: HAKENUR, WEYILO, SIREBIZU, SHEBOTETYA, TIFRENA, and CHOCHO (in Amharic). Similarly, another study in the same area [19] pointed out that recovery efforts of the lost floras have been even more difficult. Some of the returnees are encroaching and clearing both rehabilitated and natural vegetation which harbors TMPs unlawfully. Another influence of resettlement was that economic crisis of returnees—those who were totally dependent on safety net program.

Out of total 133 collected species, 17 (13%) species are endemic TMPs in the flora of Ethiopia and Eritrea. As it holds true for the total species, Asteraceae is also the leading family with five species, followed by Lamiaceae with three endemic species. These were cross-checked with different volumes of flora of Ethiopia and Eritrea and Red List book [42]. Eight of these endemic and a few other nonendemic TMP species are not described as they have been distributed in Wello floristic region (WU) in the flora. IBC [14] and Friis et al. [29] mentioned that the dry evergreen montane and grassland complex ecosystems cover the major part of the study area. Additionally, the present study revealed that the Afro-Alpine and sub-Afro-Alpine ecosystems are also found in some mountain areas and characterized by the most conspicuous endemic giant herb (Lobelia rhynchopetalum) and shrubs including Euryops pinifolius, the evergreen tree heather (Erica arborea), and perennial herb species in the study area. Hence, there is a need to strengthen conservation actions in these ecosystems to stop further threats of endemic species.

Based on the reports of informants, the trends of indicator species revealed that the last 40 decades were much detrimental to natural vegetation in the area. Furthermore, wild plants used in TMPs are being lost more quickly in wild vegetation than homegardens as illustrated in Figure 5. All the indicator TMP species which are threatened by different factors (Table 8) were reported to be greatly harvested for multiple uses they provide. The root parts used as medicine could be posing another threat. There are 113 multipurpose plants which have diverse services in terms of economical, ecological, and cultural aspects other than their medicinal values (Figure 4). The results of data matrix ranking of TMPs on five main uses showed that all the six species were the most favored for firewood although they are overexploited for other multiple uses. This goes in line with other findings [5, 6, 10, 11]. Thus, conservation strategy is needed in the area to save these species from further reduction or total extinction due to unsustainable use and overexploitation.

In view of long human settlement history of the area, the natural vegetation has enormously been altered. It came out clearly from the study that the threats facing TMPs are both anthropogenic (e.g., agricultural expansion, which is ranked 1st) and natural factors (e.g., drought), which are having detrimental effects on wild medicinal resources. This finding is in agreement with other studies conducted elsewhere in Ethiopia [7, 43]. The previous studies conducted elsewhere also confirmed that LK of wild plants in Ethiopia is in danger of being lost, as habits, value systems, and the natural environment change [6, 7].

When the pressures of threats increased and some multiuse plants became rare in the wild vegetation, most traditional healers and some local people started to conserve them by growing such species intentionally in their homegardens and farmland margins. This report is consistent with that of Asfaw and Tadesse [7], as they explained that homegarden is a strategic farming system for conservation and enhancement of TMPs. The other ways by which conservation of useful plants is effected relate to the culture of people themselves and some taboos. For instance, Phytolacca dodecandra and some Solanum spp. were not used for firewood, because the local people believe that those who used these species for firewood become poor and divorced from spouses. Furthermore, cutting of big trees with large umbrella branches was culturally not accepted because of the belief that one who cuts them will have a shortened life and may soon pass away. This is widely seen in plants like Ficus spp. (YETINCHAW LEMLEM), Euphorbia abyssinica, and Hagenia abyssinica (ADBAR-ZAF) related to spiritual issue. It also holds true for sacred forests which are found around monastery and church yards. Such habit of conserving useful plants is still alive in the study sites but is ageing in the majority of present generations. Likewise, Tamene et al. [31] reported about the preservation of forest islands by the community’s sociocultural factors as rituals. Therefore, incorporation of local communities’ own vision and LK concerning conservation and sustainable use of TMPs has to be given priority. It is likely that the local people closely watch and know how the resources are consumed and conserved [20, 44].

It is obvious that overgrazing and deforestation are very serious in northern highlands of Ethiopia. Presently, however, the local people have practiced check dam construction and tree plantation with enclosed vegetation of such highlands to reduce erosive rain storms and to preserve useful plants as well. The significance of TMPs to people can be sufficiently great that arrangements made for the conservation and sustainable use of TMPs have now grown to be a timely issue in Ethiopia. In general, biodiversity has to be protected for its multidirectional values [45, 46].

Though the local people are exposed to high cultural and habit change due to the repeated drought and resettlement conditions, the ethnobotanical knowledge on classification of their ecology and diverse use of TMPs were transmitted orally through generations. Different studies affirmed that the local people are knowledgeable about their environment in general and plants in particular [1, 33]. The findings of Giday et al. [22] indicated that boys were usually favored. Likewise, 50% of free transfers of knowledge particularly took place from parents to sons in this study. Similarly, several researchers reported that the distribution of LK is hierarchically placed and the services are obtained from the family, the village, or beyond. The secrecy of LK on medicinal practices could be one of the reasons for the uneven distribution of LK of TMPs in Ethiopia among community members [7, 21].

Comparison of LK on TMPs among age groups proves that knowledge on TMPs is wider among elderly persons while the youngsters are comparatively less knowledgeable. Since majority of young age groups are educated, modern education might have made the young generation underestimate the traditional practice. This is in line with the study of TMP in Kafficho and Butajira people [23, 47], which showed that illiterates and older residents are more likely to use traditional medicine than the educated and youngsters. Thus, age and education are main factors that appeared to influence the use of LK. On the other hand, the LK on the use of three groups of plants also varies among three groups of inhabitants. In fact, the knowledge of key informants on utilization of TMPs is proportionally high (92.6%). It is noted that the knowledge of TMPs is a means of income generation for the healers in the study sites. The folk naming of the plants by permanent residents, usually associated with their function and traits, is consistent with another study conducted by Awas and Demissew [23], which indicated that some names are attached to the disease treated and some are attributed to domestic or wild animals. However, returnees are the least knowledgeable and the names they gave to the plants were not specified. This could be due to the absence of returnees at the time of famine (1984/85). Furthermore, Martin [1] described that the knowledge on plant uses changes with time and space and with change of resources and culture. Therefore, the expansion of modern education and resettlement of people (to elsewhere) have resulted in the deterioration of LK and practices with the dislocated members of the community.

5. Conclusions

The present study indicated that the local people of Delanta are custodians of large number of TMP species (133) that they named and explained for the treatment of various human and livestock ailments (76). Notably, the highest proportion of TMPs (65.8%) were cited for human ailments. Various ethnobotanical analytical tools showed that the local people preferred some species over the others in treating ailments and other uses. About 85% of these resources also provide multiple uses. While most of the TMPs are harvested from the wild vegetation, the area is exposed to many threats such as agricultural expansion and other human induced pressures. As a result of these factors, some of the plants and the associated LK are under threat and declining. The ethnobotanical knowledge on TMP species varied among key informants, permanent residents, and returnees. Returnees were the least knowledgeable and this is one of the negative consequences of resettlement. The findings in general indicate that resettlement provided an opportunity to improve the restoration of useful plants and proved to be advantageous to biodiversity conservation in the original location (Delanta) and people should be resettled within their close community in order to avoid any disruption of their LK.

Homegardens and farmland margins have contributed to serving as preserving places of species presently in short supply and this is in need of further enhancing. Thus, strengthening the conservation of TMPs in such places is very important. For better diversity of species in general and TMPs in particular, in situ conservation measures need to be particularly directed to plant community types which could allow conservation of 50% of TMPs (Becium grandiflorum and Rumex nervosus; Otostegia integrifolia and Dodonaea angustifolia dominated community types). These potential TMP species may even give an insight for further pharmacological and therapeutic development in Ethiopia.

Conflict of Interests

The authors declared that they have no competing interests.

Acknowledgments

Ethnobotany of TMPs and the impacts of resettlement discussed herein were funded by NARF project. The authors are grateful to the taxonomic experts and the technical staff of the National Herbarium for providing materials and technical assistance during identification. They would also like to thank the people of Delanta, particularly informants and employees of district offices, for their hospitability and generous help in sharing field information pertinent to their study. The authors are also grateful to Professors Ensermu Kelbessa and Zerihun Woldu for their helpful comments on the earlier version of the research output.

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