Study Area Description
Yilmana Densa District (Woreda) is located at 11o 30׳ 0׳׳ N and 37o 20׳ 0׳׳ E in West Gojjam Zone (Fig. 1). It is bordered by Kuarit on the south, by Sekela on the southwest, by Mecha on the West, by Bahir Dar Zuria on the North, on the East by Abay River which separates it from the south Gondar Zone and by Gonji Kolela on the Southeast. The major town of this District is Adet. Yilmana Densa District has two agroclimatic Zones namely Weyna Dega and Dega Zones. Weyna Dega ranges from 1500 m to 2300 m above sea level and Dega ranges from 2300 m to 3200 m above sea level. Moist Dega ranges in its annual rainfall amount from 900 mm to 1400 mm and the amount of annual rainfall in Wet Dega is above 1400 mm .
Approximately, 24.27% of the District is Weyna Dega and 75.75% is Dega agroclimatic Zone [15, 16]. Total annual rainfall is comparatively very high with a long term mean of 1366 mm per annum. The rainy season is relatively long and lasts from May to October (Fig. 1). The District has plains, mountains, valleys and undulating areas that consist of 16, 20, 8 and 56 percent of the area respectively. The soils are moderately fertile  and they are traditionally classified into black soil, red soil and brown soil that consist of 20, 65 and 15 percent of the soil of the District respectively . According to , Yilmana Densa District has a total population of 214,852, of whom 107,010 are males and 107,842 females; 19,169 or 8.92% are urban inhabitants. The majority (98.19%) of the inhabitants practiced Ethiopian Orthodox Christianity while 1.76% was Muslim. According to the 1994 national census report this District has 48,521 households, of whom 122,135 were men and 122,668 were women; 12,178 or 4.97% of its population were urban dwellers. The largest ethnic group reported in the District was Amhara (99.94%). Amharic was spoken as a first language by 99.96% .
Quarit District is located at 11o 10׳ 0׳׳ N and 37o 15׳ 0׳׳ E and it is one of the Districts in West Gojjam Zone. It is bordered on the southwest by Jabi Tehnan, on the west by Sekela, on the north by Yilmana Densa, on the east by East Gojjam Zone, and on the southeast by Dega Damot Districts respectively. The major town is Gebeze Mariam (Fig. 1). According to , this District has two agroclimatic zones namely Dega and Weyna Dega that comprise 36 and 64 percent of the District climatic zone respectively. The main rainy seasons are May to October (Fig. 2). The temperature of the District ranges from 16-25o whereas the average amount of rainfall is 1400 mm. The District has a total area of 61473 ha among of which 44.77, 25.59 and 29.68 percent of undulating, mountains and plains respectively.
Quarit District has a total population of 114,771. This shows an increase by 16.49% over the 1994 census. Among the total population, 56,767 are males and 58,004 are females respectively. The majority of the population resides in rural area whereas the least number, 4,750 or 4.14% are urban inhabitants. A population density of Quarit is 190.34 with a total area of 602.99 square kilometers. This density shows a great variation compared to the zone average density of 158.25 persons per square kilometer. The District has also 25,402 households those result an average of 4.52 persons to a household, and 24,927 housing units. The District is inhabited by 99.9% of Amhara people, and 99.96% of the residents are practicing Ethiopian Orthodox Christianity .
The study engaged the local community and the administrators to get ideas and views on medicinal plants, threats and conservation and other related issues. To perform semi-structured interview based survey all necessary measures were taken to ensure that the ethical aspects of the local community and the Districts’ administrators were guaranteed. However, before the interviews and group discussions the study objectives and possible outcomes were described to the respondents. The values or religions of the local community were respected.
Site selection and sampling method
The sites were selected during reconnaissance survey by discussing with the Districts’ administrators, different individuals who had different background about many Kebeles, the residence of the Kebeles, agricultural professionals, rural teachers, and by observation. Following the discussion twelve rural Kebeles from Yilmana Densa District and seven rural Kebeles from Quarit District were selected (Fig. 1). The sample Kebeles of each District and the key informants were selected purposively whereas the general informants were selected using systematic random sampling method. The 19 rural Kebeles were selected based on the presence of relatively dominant vegetation covers. For the determination of the sample size of the two Districts, the following formula was applied:
Where n is the sample size, N is the population size (total number of households of the two Districts), and e (e=0.05) is the level of precision. This formula is a simplified way used to calculate the sample sizes at 95% confidence level and P = 0 . The calculation gave 395 required representative general informants for this study. After determining the amount of informants for the study, representative general and key informants of the Districts were selected using systematic random and purposive sampling (based on their relative better knowledge) approaches respectively as described by  and .
Therefore, the total number of general informants involved in ethnobotanical survey of medicinal plants of the Districts having two agroclimatic Zones (Weyna Dega and Dega) was 268 males and 127 females, separately 102 men and 45 women from Quarit District, and 165 men and 83 women informants from Yilmana Densa District respectively. Peer recommendations from community members, elderly people and knowledgeable inhabitants helped in nominating 95 key informants (68 men and 27 women). Separately 35 (25 men and 10 women) were from Quarit District and 60 (43 men and 17 women) were from Yilmana Densa District. The age of the general informants ranged from 20-81 years (139 were from 20-40 whereas 256 were > 40 years old). Informed consent was obtained from each informant who participated in this study after explaining the purpose of the study and assuring him/her of the most responsible legal use of information before the start of interviews.
Ethnobotanical data were collected during 4 different field visits conducted between 15 September 2016 and 30 June 2018. Data were collected in different seasons over different years with the objective of including different Kebeles found in the two agroclimatic Zones of the Districts, and collecting plant specimens during the respective flowering seasons. Market surveys were conducted between 10 December 2017 and 7 May 2018. Semistructured interviews, focus group discussions, participant observation, field observation and market survey were used to collect ethnobotanical data in the manner recommended by .
A semistructured interview and FGD were by using a checklist of questions prepared before hand in English, and presented by translating in to Amharic which is the common language of the local community. Informants were interviewed individually in the local Amharic language. Semistructured interviews addressed questions regarding name, age, gender, level of education, occupation, religion, nationality, District, Kebele and peasant association of each informant. All semistructured interviews were followed by independent walk in the woods exercises to pave a way for a detailed discussion with the informant and the practical identification of traditionally used medicinal plants in the natural environment.
Field observations were performed with the help of local guides, as well as some respondents of the local community. In addition, one focus group discussion (consisting of 7 participants) per Kebele was undertaken to gain detailed information on medicinal, wild edible and other useful plant knowledge at the community level and to supplement the information collected through semistructured interviews. The informants were asked about local names, habitats, parts used, collecting households, condition of plant part used (fresh/dried), ingredients used, mode of preparation, the threats and traditional conservation practices (if any) of medicinal plants [22, 23].The informants were also asked about over all use values, diseases treated, methods of remedy preparation, dosage, prescriptions and routes of remedy administration, other ingredients or additives, beliefs related to collection and use of plants .
Informant consensus factor and fidelity level were used to analyze different disease categories. Informant consensus factor (ICF) was computed to measure the level of homogeneity of the information collected and the degree of overall agreement on the treatment of specific health disorders category and to identify potentially effective medicinal plants used for the traditional treatment of disease categories in the two Districts by using the method of . During information gathering the informants were contacted three times for the same ideas to ascertain the reliability of information recorded during the first interview and the information that was repeated in the same manner by the informants at three contact times was recorded as stated by .
As described by , ICF was computed as follows: ICF = Nur – Nt / (Nur – 1), where, Nur = number of use reports from informants for a particular plant use category; Nt = number of taxa or species that are used for that plant use category for all informants. ICF values range between 0 and 1, where ‘1’ indicates the highest level of informant consent. The relative healing potential of each reported medicinal plant used against diseases was also evaluated using an index of fidelity level (FL) and it was calculated as follows: FL (%) = (Ip/Iu) X 100, where Ip is the number of informants who independently cited the importance of a species for treating a particular disease and Iu the total number of informants who reported the plant for any given disease .
Frequency Index Of Medicinal Plant Species
Frequency index was calculated to determine the percentage frequency of single medicinal plant species mentioned by informants. The following formula was used to calculate frequency index: FI = FC / N × 100 where FC is the number of informants who mentioned the use of the species, and N is a total number of informants . The frequency index is high when there are many informants who mention a particular plant and low when there are few reports.
Cultural Significance Index
The cultural significance index (CSI) was used to record the role of a species that plays in a culture by using the method of . This index was altered by  in the following way: CSI = ∑ (i. e. c). CF, where CSI = cultural significance index, i = management of the species, e = preference of use, c = frequency of use, CF = correction factor. The values of the variables “i,” “e,” and “c” are either 2 or 1 and are determined by each citation of use. i = species management (non-managed (1) or managed (2)); Species management considers the plant’s impact on the community’s daily life .
The value of 2 is given for species that are cultivated, managed, or manipulated in any way, even if in an initial manner; the value of 1 is given for species found in the area yet free from any kind of management or conservation practices. e = Use preference (not preferred (1) or preferred (2)); this represents the preference given to the use of one species in relation to another for any given purpose. The numerical value of 2 is suggested for a species preferentially used for a given purpose, and value 1 is suggested for other available species not chosen preferentially for that purpose. c = Use frequency (rarely used (1) or used frequently (2)); this considers plants effectively used. In accordance with the values designated by , a value of 2 is attributed to plants effectively known and used, and 1 is attributed to plants rarely cited. CF = Correction factor (number of citations for a given species divided by the number of citations for the most mentioned species).
Preference Ranking And Direct Matrix Ranking
Three preference ranking were exercised for three disease types (blood pressure, asthma and common cold). Sixteen key informants were selected for the preference ranking of 7 medicinal plants (Croton macrostachyus, Dovyalis abyssinica, Lupinus albus, Phragmanthera regularis, Rosa abyssinica, Thymus schimperi and Verbascum sinaiticum) that used to treat blood pressure. The same number of key informants was also asked to rank 4 medicinal plants (Verbascum sinaiticum, Rubia cordifolia, Dovyalis abyssinica and Catha edulis) that used to treat asthma. Moreover, 6 medicinal plants (Echinops kebericho, Eucalyptus globulus, Olea europaea subsp. cuspidata, Otostegia integrifolia, Ocimum urticifolium and Rumex nervosus) used to treat common cold were also ranked by the same number of key informants.
The method of descriptive statistics was applied to identify the number and percentage of species, genera and families of medicinal plants used, their growth forms, proportions of parts harvested, modes of remedy preparation and routes of administration .
Market surveys were conducted at three market places namely Adet, Dabi and Bir Gebeya whose market date is going on Saturday and Wednesday for the first two and Friday for the later respectively. The purpose of market survey was to record, document and analyze the availability, price and unit of measurement, extent of use and income - generating potential of medicinal plants found in these markets.