Pulak Das

Community Metrics Under Air Pollution Stress Condition

The chapter deals with the pattern of changes in the diversity components of lichen communities around a paper mill in northeastern Indian region. Four indices (Shannon index, Pielou index, Margalef index, and Simpson index) are calculated for the seventeen sites situated within a radius of 25 km from the mill. The indices are studied vis-a-vis the distance (from the mill) and elevation. Positive correlation is found between number of species and distance, while a negative correlation is found between numbers of species and the elevation. Changes in the pattern of indices are seen along three distance categories; 20 km. As expected, the dominance index increased (54 %) and the diversity, richness, and evenness index decreased near the mill; maximum decrease being for Shannon index (>14 %) of diversity. It is observed that neither of the indices showed significant correlation with the altitude or distance. The Shannon, Margalef, and Simpson index showed significant correlation with the number of species. The effect of stress on biodiversity is depicted with the help of changes in the shapes of Odum’s model of ‘concave’ curve. It is observed from the graphical representation of the ‘number of species’ and ‘number of individual per species’ that the nearness to the mill converted the ‘concave’ hollow curve into a flattened one and ultimately into a ‘convex’ curve.

Homegarden Lichens-A Prospective For Ethnolichenology in Barak Valley, Assam

The present study explores the lichen flora in traditional homegardens in Panchgram area of Barak valley, southern Assam. Homegardens are important component of rural socioeconomy in northeast India and are preserved through traditional wisdom of local communities. Homegardens mimic forest structures and harbour rich diversity of cultivated as well as natural floral composition helping in conservation of important lichens of the region which hold in it tremendous potential of ethnolichenological use for present and future. The present work enumerates 68 lichens representing 22 genera and 11 families found in randomly selected homegardens in an area of about 28 km2 around Panchgram. Out of these 68 lichens, 10 exhibit foliose growth form and remaining 58 lichens exhibit crustose growth form. Graphidaceae is the dominant family representing 22 species followed by Pyrenulaceae (17 species) and Arthoniaceae (10 species). Pyrenula (17 species) is the dominant genus in the region followed by Arthonia with 8 species and Phaeographis and Graphis with 7 species each. The common homegarden lichens Parmotrema tinctorium, Parmotrema saccatilobum and Graphis scripta which are found during the study have ethnolichenological uses recorded in various literature studies. Ethnolichenological studies are very scarce in northeast India. Owing to rich ethnic and floristic diversity in the region, present study suggests the role of homegardens in conserving lichens which might have unexplored traditional use by indigenous communities and needs proper documentation.

Exploration of homegardens as important lichen conservation areas in dargakona village of southern assam, Northeast India

Homegardens create a forest like multistory structure with different vertical and horizontal layers and its characteristic species diversity. The present paper throws light on the importance of homegardens as a significant lichen refuge. The study explored a lichen diversity of 44 species with a representation of 17 genera and 9 families. Graphidaceae is the dominant family followed by Pyrenulaceae and Arthoniaceae. Graphis and Pyrenula are found to be the dominant genera representing about 40% of total species richness. It is observed that the homegardens are shelters to about 15% of lichens which have restricted distribution (endemic) in eastern Himalayan region. The traditional wisdom along with ecological knowledge of the local people in maintaining homegardens in northeastern region seems to be helping in conserving the genetic heritage of wild lichen species of eastern Himalayan region. This becomes more important in the wake of wanton destruction of forests and hence lichens growing there.