Ethnomedicinal and ecological status of plants in Garhwal Himalaya, India

Details of study area

Ecological information about medicinal plant species was collected in three different climatic regions of Garhwal Himalaya: tropical, sub-tropical, and temperate regions at an average altitude of 350, 1100, and 2300 m a.m.s.l. (Figure 1), and their medicinal use was documented. The tropical region was primarily flat with a few south west facing hills. The sub-tropical region also faced toward south west. The temperate sites were south east facing. The summer season in the tropical region is very hot and temperatures range between 18-24°C. In sub-tropical region, which is mildly hot in the summer season, temperatures range between 17-23°C, and in temperate region temperatures range between 7-15°C, with some days below freezing in winter (October to February). The tropical region is part of the Pauri Garhwal district in the foothill region of Garhwal Himalaya. The sub-tropical and temperate regions are in Tehri Garhwal district. The total population of the villages was 1140 inhabitants in the tropical, 374 in the sub-tropical and 464 temperate regions respectively. Ten percent of the population (114, 38 and 47) was interviewed. Further details of the regions are given in Table 1.

Figure 1

Location map of the study area.

Data collection and analysis

Ethnomedicinal inventory

Information on plants with ethnomedicinal uses was collected from informants living in villages adjacent to the surrounding forest. After establishing oral prior informed consent in village meetings, about 10% of the inhabitants were interviewed about their dependence on the forest for various products, especially for medicinal purposes. The informants were randomly selected and included older men and women, well versed in the identification of plants, who regularly used and visited the forests since their childhood and used plants to cure various ailments. In the initial selection of informants younger participants were considered, but were later excluded because initial interviews indicated that they did not have much knowledge about medicinal plant use. The interviews were conducted in the local dialect to avoid translation problems. During the interviews structured questionnaires were used to obtain information on medicinal plants, including the local name of the plant, name of the disease for which a particular plant was used, part of the plant used etc. The informants were asked to show the plants in their natural habitat. Specimens of all plants were then collected and identified at the Garhwal University Herbarium (GUH), using [23].

Consensus survey

A consensus survey was conducted based on peoples opinion on the number of plants used for a particular ailment. The consensus factor (Fic) was used to test the homogeneity of the informant's knowledge according methods described by Trotter and Logan [24] and Ragupathy et al. [25]

The consensus factor was calculated as follows

Fic=Nur-Nt∕Nur-1

The resulting factor ranges between 0 to 1, where a high value indicates for a high rate of informant consensus. N_ur is the number of use-reports of informant's for a particular illness, where a use-report is a single record of the use of a plant mentioned by an individual, and N_t refers to the number of taxa (species) used for a particular illness category by all informants.

Ethnomedicinal uses

Ethnobotany is not new to India [26] with over 400 different tribal and other ethnic groups [27,28]. Ethnobotanical information on medicinal plants and their uses by indigenous cultures is useful not only for the conservation of traditional knowledge and biodiversity, but also to promote community health care, and might serve in drug development. The information can provide a guide for drug development, assuming that a plant that has been used by indigenous people over a long period of time may well have an allopathic application [29,30].

Table 2 provides the scientific names for all plants collected, as well as information on the parts used. Overall 14 trees, 10 shrubs, and 33 herbs were identified. These plants were used to treat a total of 47 diseases, ranging from simple to highly complicated, including asthma and respiratory problems. The greatest number of plants (7) was used for digestive disorders, followed by fever (6) and bronchitis (5). A single species was recorded to treat each of the following ailments: warts, vomiting, carminative, pains, boils, and much other species (Figure 2).

Figure 2

Number of plants used for different disease curing.

A comparative study in Bhotiya tribal communities in the Central Himalaya found that eighty-six plant species were identified as being used for treatment of 37 common ailments [31].

A study on the status of medicinal plants in Uttarakhand Himalaya [32] found a total of 243 medical herbal formulations prepared by Vaidyas (healers) treating 73 different ailments. Plants were used as the major ingredients for these medical formulations. A total of 156 medicinal plant species were documented during the survey. Of these 55% were cultivated and 45% were wild collected.

The plants found in the present study are distributed among 30 plant families. The largest number of species (7) belonged to the Lamiaceae followed by Asteraceae, Rosaceae, and Fabaceae with five species each (Table 3). A study of medicinal plants in the trans-Himalayan arid zone of Mustang district, Nepal, also found the largest numbers of medicinal plants belonged to the Lamiaceae [33].

A field survey conducted in four different places of Kathmandu valley recorded thirty six medicinal plants used to treat ailments such as diarrhoea, stomach ache, gastritis, jaundice, bodyache, bleeding, etc. [34]. The results indicate that inhabitants of the Kathmandu valley still rely on traditional medicines for their primary health care. The indigenous knowledge of local traditional healers in the Kancheepuram district of Tamilnadu also showed that many people still continue to depend on medicinal plants at least for the treatment of common health problems [35].

In the present study most preparations used the whole plant, followed by leaf and roots (Figure 3). A study conducted in Chakrata Forest Division, Uttarakhand, showed a higher incidence of root, leaf, and bark use to treat various diseases [36].

Figure 3

Number of plants parts used for disease curing.

Traditional medicines are a central component in health care systems in developing countries, where up to 80% of the population depends on traditional medical systems. The use of herbal medicines, is also increasing in developed countries, based on the belief that herbal remedies are safe because of their natural origin [37]. Globally, there are about 120 plant-derived drugs in professional use; three quarters of which are obtained from traditional medicinal plants [38]. Unfortunately, according to a recent report, almost one third of medicinal plant species could become extinct, with significant losses reported in China, India, Kenya, Nepal, Tanzania, and Uganda [39]. Greater losses are expected to occur in arid and semi-arid areas due to the impact of climate change, erosion, expansion of agricultural land, wood consumption, and exploitation of natural vegetation, increased global trade in natural resources, domestication, selection and grazing [40].

The traditional plant knowledge however is disappearing in many communities because of rapid socioeconomic and cultural change. The sustained use of this knowledge and its documentation is therefore essential.

Ecological status

In the present study, the distribution of species ranged from altitude 350 m to 2300 m m.a.s.l. The vegetation composition varied with changes in altitude. Plant resources distributed across complex landscapes modified for human needs [11]. For example, conservation agencies recognize geographically uneven occurrences of high species richness and rare and endemic plants in their designation of biodiversity hotspots [40-42] or ecoregions [43,44]. These localities are then prioritized by the degree to which human activities threaten existing patterns [45]. Diversity patterns at different geographic scales, however, may be created or degraded by physical-environmental conditions and human-historical processes that influence resource availability and habitat heterogeneity [46,47].

In this study, we focused on the ecology and ethnomedicine of woody and herbaceous plants. These plants are distributed in highly-fragmented habitats, and are potentially threatened. Among the high peaks of the Himalaya, local inhabitants were found to inflict a great deal of pressure on medicinal plant populations because at higher altitudes health care facilities were almost nonexistent, and people met their medicinal requirements with forest products. At lower altitudes, people also used medicinal plants, but owing to better infrastructure, they also used nearby health centers for the treatment various diseases.

To promote a conservation agenda, it is important to understand how local communities use and manage natural resources. Studies in ethnobiology (including ethnobotany) and traditional ecological knowledge are known to serve as significant bridges between conservation scientists and local communities. These studies help to explain how local communities relate to their environment and hence, suggest ways to promote their active involvement in natural resource conservation [48].

The ecological information of plants is given in Table 2. A total of 57 species were recorded from all three regions (tropical, sub-tropical and temperate). Among the trees, Acacia catechu, Aegal marmelose, Ougeinia oojeinensis, Terminalia belerica, and Terminalia tomentosa were common in the tropical and sub-tropical regions. Acacia catechu was dominant in the tropical and sub-tropical regions. Ougeinia oojeinensis was the least common tree in the tropical region and Terminalia belerica in sub-tropical region. In the temperate region, Quercus leucotrichophora was dominant and Pyrus pashia least dominant. Other associated species are shown in Table 2. In the shrub layer, a total of 10 species were recorded from all regions: Three species were found in tropical areas, 4 in sub-tropical areas, and 5 in temperate areas. Adhatoda vasica was found in both tropical and sub-tropical regions, while Rhus parviflora occurred in both sub-tropical and temperate regions. Among the 33 species of herbs, Sida cordifolia was dominant in tropical and sub-tropical region while least dominant herb in the tropical region was Barleria prionitis, and in the sub-tropical region Achyranthes aspera and Aerva sanguinolenta. In the temperate areas, the dominant and least dominant species were Vernonia anthelmintica and Imperata cylindrical respectively. Other associated herbs are given in Table 2.

The density and total basal cover of trees, shrubs and herbs in the tropical, sub-tropical and temperate regions is shown in Figures 4a, 4b, and 4c. In the tree layer the highest value of density (698 trees ha^-1) and total basal cover (16.45 m² ha^-1) was in temperate region followed by sub-tropical and tropical regions (Figure 4a). In the shrub layer the density and total basal cover was highest in sub-tropical region and lowest in the tropical region (Figure 4b). In the herb layer the trend of density and total basal cover was inverse to the tree layer and highest in the tropical region, followed by the sub-tropical and temperate regions (Figure 4c). The trend of tree density and total basal cover increased with increasing altitudes. Shrubs were increasing in the sub-tropical region. The dependency of the villagers on medicinal plants increased with increasing altitudes due to increasing lack in healthcare facilities. Herb density and total basal cover were reduced with altitude, which could be the main effect of exploitation of these medicinal herbs for human health.

Figure 4

Total density and total basal cover of various areas at each altitude. Trees (4a); shrubs. (4b) and herbs (4c).

Most of the informants suggested that medicinal plants are an important source for daily healthcare and the associated knowledge was traditionally transmitted. They also suggested that these species help maintain the ecological balance of the area by decreasing soil erosion and increasing moisture in the soil, thus improving conditions for human and livestock needs. Most of the respondent said however that they did not apply any management or paid any attention to conservation needs of the species because of lack ecological knowledge. People were well aware that deforestation, overgrazing, and overexploitation of the species in a particular region may lead to the extinction of this valuable resource. The changing ecological situation was recognized as a main reason for severe problems like forest fires, erosion and drought, as well as for the disappearance of important medicinal species. The expansion of agriculture, and logging was mentioned as clearly reducing the population of highly valuable medicinal plants.

Consensus survey of medicinal plants

The consensus survey indicated that six plant species were used most commonly for individual diseases, and therefore the informant's consensus index factor was high (1.0). Two taxa were often used for five other diseases (the index factor range was 0.75 to 0.98). Digestive diseases were cured with the highest number of taxa (7) and its consensus index factor was 0.84 (Table 4). The local population had a very high level of agreement on the usages of plants for specific ailments. The index value was high for warts, vomiting, carminative, pain, boils and antiseptic uses (1.0), and lowest for bronchitis (0.33) were five (5). Ragupathy et al. [25] published first consensus analysis research for aboriginal group in India. The consensus report of northeast India is also carried out by Sajem and Gosai [49].