Assessing land-use changes driven by river dynamics in chronically flood affected Upper Brahmaputra plains, India, using RS-GIS techniques

This work documents land-use changes driven by river dynamics along two tributaries in the chronically flood affected Upper Brahmaputra floodplain which supports a population of more than half a million. Planform changes for a period of 40 years are documented using topographical map and Landsat data, and the associated land-use change is assessed by utilising hybrid classification in GIS environment. Quantification of bankline migration shows that the river courses are unstable. A reversal in the rate of erosion and deposition is also observed. Hybrid classification of Landsat images yielded a higher level of accuracy as evident from the confusion matrixes. Overall, the accuracy of land-use classification ranged between 88.5% and 96.25%. Land-use change shows that there is an increase in settlement and agriculture and a decrease in the grassland. The area affected by erosion–deposition and river migration comprises primarily of the agricultural land. Effect of river dynamics on settlements is also evident. Loss of agricultural land and homestead led to the loss of livelihood and internal migration in the floodplains. The observed pattern of river dynamics and the consequent land-use change in the recent decades have thrown newer environmental challenges at a pace and magnitude way beyond the coping capabilities of the dwellers

Economic significance of wild bioresources to rural communities in the Eastern Himalayan state of Assam, Northeast India

Wild bioresources are indispensable for the survival and sustenance of ethnic and rural communities, especially those of Northeast (NE) India which has a rich heritage of indigenous traditional knowledge on biodiversity and bioresources. This study investigates the trade of wild bioresources throughout the Eastern Himalayan state of Assam along with the socioeconomic attributes of the communities involved in the trade system. Surveys and interviews were executed in local markets and village households. Interviews were carried out with vendors and consumers in 30 weekly markets, and with household heads in 550 households using open-ended structured questionnaires. A systematic database on species diversity, distribution, use pattern, availability, local market economics and community details was assembled, from which standard values of commodities were computed to facilitate uniformity of market values. The study recorded 5 species of wild edible mushrooms, 158 species of wild plants and 11 species of animals available in local markets. Among these 78.7% are consumed as food, while 77 of the total species are medicinal. In some markets, products of species like Amaurornis phoenicurus, Canarium strictum, Elaeocarpus ganitrus, Hystrix indica, Lentinus polychrous, L. squarrosulus, Ocimum basilicum, Piper longum and Termitomyces sp., were sold at a high price of 6.5–65 USD/kg. It was observed that trading wild bioresources contributes 5–75% to the total income at a majority of the households. The present study highlights that wild bioresources are indeed significant for the subsistence of rural communities in Assam, with the potential of improving local economies and promoting community development. Through effective policies and conservation strategies, local communities should be encouraged and empowered to sustainably manage biodiversity and bioresources in the wake of climate change