Indigenous knowledge and use of lichens by the lichenophilic communities of the Nepal Himalaya

The present study was conducted in three districts (Taplejung, Solukhumbu, and Gorkha) from two different regions (Eastern and Western) of Nepal (Fig. 1). The authors (SD, RPC) have accumulated sound knowledge on ethnic values of wild resources during their frequent visits to several mountainous Districts of Nepal prior to this research. Prior information played instrumental roles in selecting research areas. Eight field surveys mainly during summer season, roughly 15 days in duration, in the 22 different village development committees (VDCs) were carried out during 2011–2013 to collect ethnolichenological data. The following areas were selected to document ethnic uses of lichens: Olangchung Gola and Ghunsa Valleys located in Kangchenjunga Conservation Area of Taplejung District (N27°37′32.6958″, E87°46′34.7982″); Dudhkoshi and Dudhkunda Valleys located in Sagarmatha National Park (SNP) and surroundings of Solukhumbu District (N27°47′27.5028″, E86°39′39.9882″) in Northerneastern Nepal. Limbu, Rai, and Sherpa are main dwellers in these areas and for these communities, lichens play an important economic and cultural role. In Taplejung District, Phungling, Hangdeva, Phurumbu, Linkhim, Tapethok, Lelep, and Olangchung Gola, Village Development Committees (VDCs) were visited. In Solukhumbu, the settlements of Salleri, Beni, Taksindu, Jubing, Chaurikharka, Namche, and Khumjung VDCs were visited.

The Nubri and Tsum Valleys of Gorkha District (N28°28′35.0178″, E84°41′23.1″) located in Manaslu Conservation Area from Western part were selected as transition zone between Eastern and Western Himalayas. Scientifically, this area is poorly explored and less is known about biodiversity or social and cultural aspects from this valley because of its remoteness. In Gorkha, the VDCs of Lapu, Uiya, Sirdibas, Bihi, Prok, Samagaun, Chumchet, and Chekampar were visited. Gurung, Chhetri, and Sherpa are the main indigenous dwellers in this area.

Random and snowball sampling methods were employed to collect primary data [23, 24]. Respondents, who either collected, bought or at least used lichens even for a single purpose were selected for face-to-face interview using semi-structured questionnaires (Table 1). In some additional cases, though, respondents were not aware of any uses of lichens; their name, ethnic group, age, religion were asked for the further analysis to know the demographic nature of such respondents. Respondents were not forced to give their real names, answers to all the questions from a list and were not asked as in question order. Prior informed consent [25] was taken verbally from key informants including local healers before documenting their traditional knowledge on various uses of lichens. Group discussions, informal meetings while staying with local communities and field observations with key-informants were carried out. Species recommended during participatory field observations were collected. For each species they identified, informants were asked to give details of their knowledge on uses and spiritual/ritual values and these were cross-checked at least with three respondents for their validity.

To calculate the statistical significance of differences between uses and variables characterizing the local population (location, age group, sex, caste and ethnicity), Pearson’s Chi-squared test (χ ²) was applied [26] using the statistical software R [27].

The lichen specimens were identified by studying morphology, anatomy and lichen substances. Specimens were brought to the Swiss Federal Research Institute WSL, Switzerland where chemical substances were identified with standard thin-layer chromatography (TLC) techniques [28, 29]. Identified specimens were stored in the Tribhuvan University Central Herbarium (TUCH), Kirtipur, Kathmandu, Nepal.

A total of 190 informants (87 male and 103 female) representing seven age groups (<12, 13–24, 25–35, 36–47, 48–59, 60–71, >72 years), nine communities (Brahman, Chhetri, Dalit, Gurung, Lama, Limbu, Rai, Sherpa and Tamang), and three cultural backgrounds (Buddhism, Hindu, Kiraat) from eight altitudinal levels (≤1000 m, 1000–1400 m, 1400–1800 m, 1800–2200 m, 2200–2600 m, 2600–3000 m, 3000–3400 m and ≥3400 m) were approached (Additional file 1). Of the total 190 informants, 82% (N = 156) know at least a single use of lichens or have heard about their uses. These 156 respondents were interviewed in detail using the semi-structured questionnaires.

Highly used vernacular names for lichens are ‘Jhyauu’ or (translation: unnecessary stuff) and ‘Jhulo’ (translation: brittle things for the ignition) and even between the two, the most generalized name is Jhyauu. In addition, we documented 16 vernacular names used by indigenous peoples and ethnic groups in different parts of Nepal (Table 2). The vernacular names are derived mostly from gross morphology, life forms and palatability. Limbu and Rai called lichens as Yangben. Two different names ‘Maangmaa’ and ‘Myann’ among Sherpa ethnic group referred to edible and inedible lichens, respectively. Interestingly, it was found that people considered Thamnolia vermicularis, locally called Dankini Chyau (Witch mushrooms) as a mushroom species. Not a single respondent considered it a lichen. It was a big surprise for them to learn their real nature.

Our study revealed six uses of lichens in the study areas. Medicinal value (MV), ritual and spiritual value (RSV), food value (FV), aesthetic and decorative value (ADV), bedding value (BV) and ethno-veterinary value (EVV) are the major uses of lichens. Among the 156 respondents, use percentages were high (51%) for medicinal values (MV) and low for ethno-veterinary value (2%). Ritual and spiritual values (RSV) and food value (FV) were represented with 41% and 31%, respectively. For aesthetic and decorative values (ADV) and bedding values (BV), use percentage was 13% (Fig. 2).

Seven lichen species are particularly important among the respondents for various uses. Among these, use percentage was highest for Heterodermia diademata (49%) and lowest for Ramalina sp. (3%). Use percentage of Everniastrum cirrhatum, E. nepalense, and Usnea longissima were 40%, 38%, and 30%, respectively. For Parmotrema cetratum and Thamnolia vermicularis, use percentages were 31% (Fig. 3).

Respondents from nine communities used seven lichen species to meet their demands regarding the six lichen uses (Table 3). Among those, Heterodermia diademata and Ramalina species were used for medicinal values, Everniastrum cirrhatum, E. nepalense, and Parmotrema cetratum for food value, Usnea longissima for the ritual, spiritual, aesthetic values and as bedding materials, and Thamnolia vermicularis for the aesthetic and spiritual values. Interestingly, H. diademata was used by all ethnic communities.

Forty nine percent of respondents (N = 77) used Heterodermia diademata to treat wounds and to stop bleeding after an injury. Extracts or juices of Artemisia vulgaris or Eupatorium odoratum mixed with this lichen species are used to cure fresh wounds or cuts. Regarding the medicinal value (MV), a significant difference (p = <0.05) was observed with altitudinal gradients, cultural groups and ethnicity (Table 4). Two respondents (>72 years) from Hangdewa and two (60 and 71 years) respondents from Phurumbu, Taplejung District used Ramalina sp. as antiseptic tincture to heal wounds.

Regarding the food value (FV), a significant difference (p = <0.05), was observed according to altitudinal levels of the studied areas, religion and ethnicity (Table 4). Although lichens occur from outer Tarai to the high mountains, the use of lichens in cuisine is observed only among Limbu, Rai and partly with Sherpa and Tamang ethnic groups. These groups are major dwellers of Eastern midhills and mountainous regions of Nepal. Major dishes prepared with steamed lichens are pickle, curry, soup and sausages. Twenty six percent of the respondents prepared dishes of Everniastrum nepalense, E. cirrhatum and Parmotrema cetratum. Freshly harvested (Fig. 4) or purchased lichens (about 250 g) are boiled for about 1 h with ash (about 50 g), rinsed in clean cold water until any yellow color is gone, sun dried on bamboo woven baskets and placed in closed containers in a dry place. Boiled and dried lichens can be stored for a year. For bread making, boiled, dried and powdered lichens are mixed mainly with wheat or barely flour (1:3 mixed lichens and flour).

Limbu people prepare a special traditional dish called Sargyangma made of lichens to celebrate their special gatherings and social functions like Dashain, Tihar and in some cases, when a pig is slaughtered in the community (Fig. 5). Sargyangma is a kind of sausage made up of minced pork, pork’s blood, eggs, fat, rice grains (optional), spices, onion, garlic, chilly, turmeric powder, ginger, salts and lichens inserted in the pork’s big intestines. Filling of ingredients should not be compact. Boiled and dried lichens is ground fine and mixed with other ingredients. Sometimes, Sargyangma is specially prepared for old elderly people during the festivals who cannot eat meat because of their weaker teeth.

Everniastrum cirrhatum, E. nepalense and Parmotrema cetratum were much preferred species and found to be sold in local weekly markets in the district headquarter of Taplejung. Our study found that since the last 5–7 years, the demand for edible lichens is rising, especially from abroad. Thousands of Rai and Limbu families from Eastern part of Nepal are living abroad (mainly in UK and Hongkong) and they want to taste lichen during their festivals. Lichens are also considered as the best gift item in such communities.

Thamnolia vermicularis was used on the belief that this lichen wards off evil spirit and maintains peace at home and among family members. Respondents kept a handful of lichens above the main entrance of a house. Twenty two respondents (male 10, female 13) from six villages (Hangdewa 1, Lelep 1, Linkhim 2, Phurumbu 3, Tapethok 4 and Olangchung Gola 12) of Taplejung District used this lichen. Such practice was common among the Buddhist and Kirant cultural groups. Similarly, people of Olangchung Gola and Ghunsa used Usnea longissima to clean religious cups like butter lamps (Diyo in Nepali) and water bowls made of silver. With wet U. longissima, pots are scrubbed to remove stains.

Usnea longissima and Thamnolia vermicularis were used as ingredients in incense powder mainly by the Sherpa (N = 30) and Lama (N = 11) ethnic groups, residing in Olangchung Gola, Ghunsa and Tsum valleys. They mixed these dried lichens with dried leaves of Juniperus indica, J. squamata, Rhododendron anthopogon, R. decorum, R. lepidotum and roots of Jurinea dolomiaea. They burn incense powder during their morning pray and religious ceremonies which releases pleasant and fragrant smoke.

Among the six lichen uses which we identified in our research, food value (FV), medicinal value (MV), animal bedding value (BV) and ethno-veterinary value (EVV) include in provisioning services whereas ritual and spiritual values (RSV) and aesthetic and decorative values (ADV) relate with cultural services. From this study, it is found that the Kiraat religious group (Limbu and Rai) is using three lichen species (Everniastrum nepalense, E. cirrhatum, Parmotrema cetratum) mainly for their food value (FV) while the Buddhism religious group preferred lichens (Heterodermia diademata, Usnea longissima, and Thamnolia vermicularis) for medicinal (MV) and ritual and spiritual values (RSV). Only a low number of Hindu respondents (Brahman and Chhetri) were using lichens (Fig. 6).