Study Area The Bandarban is a hilly district situated in South-Eastern Bangladesh with an area of 4479.03 sq. km., between 210 11′ and 220 22′ North latitudes and 920 04′−920 41′ East longitudes. It is bounded by the Rangamati district in the north, Myanmar in the south, Chin Province (Myanmar) and Rangamati district in the east, Chittagong and Cox’s Bazar districts in the west. The economy of Bandarban is predominantly agricultural (61.95%), mainly through Jhum cultivation. Of lesser importance is the commercial sector (9.92%), service industries (8.12%) nonagricultural labor (7%) and miscellaneous others of 1% each or less (Banglapedia, 2003). Out of the entire district area, forests and rivers occupy about 2730.48 sq. km. (60.96%) and 3.16 sq. km. (0.07%), respectively. The annual average temperature of this district varies from a maximum of 370C to a minimum of 12.50C. Annual average rainfall is 3031 mm.
Field Study and Data Collection The field survey was carried out during both winter and summer seasons from January to April 2017. Three of the seven Bandarban district Upazilas were selected for the current study, namely Naikhyonchari, Rowangchari, and Ruma Upazilas (Figure 1). These three Upazilas were chosen due to their distance from cities, occupying some of the remotest areas of Bangladesh. A total of 12 indigenous communities live in the study area, including Bawm, Chak, Chakma, Khumi, Khyang, Lushai, Marma, Mro, Pangkhoa, Rakhaine, Tanchayanga, and Tripura (Uddin, 2014) Of these, three indigenous communities, namely, Chak, Marma, and Tripura, were included in the present study, as these communities were reported to use ethnomedicinal herbal practices heavily. Table 1 lists the details of visited areas along with their GPS readings. Ethnomedicinal data were documented through direct observation, field interview, group interview, and plant interview, by adopting open-ended and semi-structured question techniques (Martin, 1995; Alexiades and Sheldon, 1996). Audio and video recording was done throughout all interviews.
Ethical Issues No explicit rules or regulations pertain to the practice of ethnomedicinal research in Bangladesh. Participants in the study had the purpose of the research project explained to them before they gave oral informed consent. Each participant of the study agreed to participate voluntarily. Participants were allowed to discontinue the interviews at any time. Upon completion of the study, all data will be included online at www.ebbd.info and www. mpbd.info.
Plant Collection, Identification, and Preservation Voucher specimens were collected through repeated field trips. While noting the information, care was taken to document all kinds of relevant taxonomic characteristics. The identification was done by consulting with an expert: Professor Dr. Shaikh Bokhtear Uddin, Department of Botany, University of Chittagong, Bangladesh, and through several literature sources. The identified plant species were further compared with the “Dictionary of Plant Names of Bangladesh (vascular plants)” (Pasha and Uddin, 2013) for justification of correct scientific names and author citations. Voucher specimens were deposited at the Chittagong University Herbarium (CTGUH), Department of Botany, University of Chittagong, Bangladesh.
Quantitative Ethnobotany Informant Consensus Factor (ICF) Informant Consensus Factor (Logan, 1986; Heinrich et al., 1998) was calculated using the following formula:
FIC = Nur − Nt/(Nur − 1)
Where, “Nur” refers to the total number of use reports for each disease cluster and “Nt” refers the total number of species used for that cluster. This formula was used to find out the homogeneity in the ethnomedicinal information documented from the traditional informants.
Jaccard Index (JI) This index is used to compare study data with that of other ethnobotanical studies conducted in other parts of Bangladesh as well as other countries in the world, and also among the indigenous communities in the studied areas. The formula to evaluate the JI index (González-Tejero et al., 2008) was:
JI=cx100/a+b-c, where, “a” is the recorded number of species of the study area “A,” “b” is the documented number of species of the area “B” and “c” is the common number of species in both area “A” and “B.” In case of indigenous communities, “a” is the number of species reported by an indigenous community “A,” “b” is the number of species cited by the indigenous community “B” and c is the number of species reported by both “A” and “B.”