Tribal institutions and conservation of the bioculturally valuable ‘tasat’ (Arenga obtusifolia) tree in the eastern Himalaya

This study reports on the biocultural dimensions of the tasat (Arenga obtusifolia Griff.) tree and its conservation by various informal institutions of the Adi tribe of Arunachal Pradesh, India. The study included 240 Adi community members (120 men and 120 women) residing in 12 villages of the East Siang and Upper Siang districts of Arunachal Pradesh. The study was conducted using personal interviews and participatory methods. Results indicated that the stem of tasat is used as a traditional food during droughts and in preparing an ethnic beverage. Tasat is being conserved by the Adi tribe in various habitats. Plant populations of tasat were observed relatively higher in Upper Siang than the East Siang district. The study found differences in the status of biocultural knowledge between genders and different age groups. Kebang and reglep are two indigenous institutions of men and women, respectively, and play leading roles in sustaining tasat plants in various habitats. Women of the Upper Siang district still maintain a knowledge network for diffusing biocultural knowledge related to tasat, among others, through a barter system. Changing land use patterns in agriculture affects tasat conservation. The value addition for tasat based products, and rewarding women who conserve tasat, can enhance the sustainability of tasat based on biocultural knowledge and institutions.     

Naturally occurring thallium: a hidden geoenvironmental health hazard?

This paper illustrates a real environmental concern and draws attention to the fact that natural processes can mobilize thallium (Tl), a highly toxic metal, which may enter the food chain as a "hidden health killer" with severe health impacts on local human population. Natural processes may be exacerbated by human activities such as mining and farming, and may cause enrichment of Tl in the environment. In geochemically anomalous areas with concentrated levels of Tl in the surface environment (bedrocks, waters, soils, and crops), such as the Lanmuchang area in southwestern Guizhou Province, China, it is essential to establish base-level values and to pay heed to the geological context of "natural contamination," as high concentrations of Tl in bedrocks/ores (6-35,000 mg/kg) can lead to enrichment of Tl in the aquatic system (0.005-1100 microg/l in groundwaters and 0.07-31 microg/l in surface waters) and soil layers (1.5-124 mg/kg). In sensitive areas such as the Yanshang area of southwestern Guizhou, elevated natural levels of Tl from bedrocks may also cause higher concentrations of Tl in the surface environment, and thus more attention must be paid to geoenvironmental management of human activities if socio-economic catastrophes are to be avoided. Due to high uptake of Tl by crops, Tl can be transferred from soils to crops and remarkably concentrated in food crops. Concentrations of 1-500 mg/kg Tl based on dry weight (DW) were determined in many food crops growing on Tl-contaminated arable soils from the Lanmuchang area. The daily intake of 1.9 mg of Tl from consumed food crops was estimated for the local adult inhabitant of Lanmuchang. Thus, Tl is regarded as a latent health hazard with potential risk of toxicity in humans within areas of "natural" contamination by Tl.     

Agro-biodiversity in rice–wheat-based agroecosystems of eastern Uttar Pradesh,India: implications for conservation and sustainable management

In this study, we analysed the indigenous practices of agro-biodiversity, changing patterns of cropping systems and conservation of agriculturally important natural resources of rice–wheat-based agroecosystems. The research was carried out in three villages of Azamgarh district, eastern Uttar Pradesh, India. Participatory approaches and personal interviews were combined to collect the data from 180 farmers. The results indicated that resource-poor (RP) farmers, by applying traditional practices of natural resource conservation, outperform their rich (RR) counterparts in conserving agro-biodiversity. Increase in irrigation facilities, adoption of improved crop varieties, commercialisation of farming and socio-economic changes have threatened the agro-biodiversity and related natural resources of these agroecosystems. For most of the crops, the RP farmers had better production stability as compared to the RR ones because the former tend to apply more sustainable and ecologically sound indigenous practices. A negative growth rate was observed in the area/numbers and production of legumes, livestock, pasture lands and community forestry. Women, who are the local custodians of conserving indigenous biodiversity (uncultivated species) and crop varieties through localised knowledge and sociocultural institutions, had significantly higher knowledge on agro-biodiversity than men. We concluded that integration of farmers’ eco-friendly practices with formal science and policy-making in a participatory mode may enhance sustainability of functions of agroecosystem leading to the strengthening of adaptive practices in changing climate and socio-economic scenario.     

A Stochastic Modeling Approach to Address Hydrogeologic Uncertainties in Modeling Wellhead Protection Boundaries in Karst Aquifers1

Abstract: Development of any numerical ground‐water model is dependent on hydrogeologic data describing the subsurface. These data are obtained from geologic core analyses, stratigraphic analyses, aquifer performance tests, and geophysical studies. But typically in remote areas, these types of data are very sparse and site‐specific in terms of the aerial extent of the resource to be modeled. Uncertainties exist as to how well the available data from a few locations defines a heterogeneous surficial aquifer such as the Biscayne Aquifer in Miami‐Dade County, Florida. This is particularly the case when an exceptionally conductive horizontal flow zone is detected at one site due to specialized testing that was not historically conducted at the other at sites that provided data for the model. Not adequately accounting for the potential effect of the high flow zone in the aquifer within a ground‐water numerical model, even though the zone may be of very limited thickness, might underpredict the well field protection capture boundaries. Applied Stochastic ground‐water modeling in determining well field protection zones is steadily becoming important in addressing the uncertainty of the hydrogeologic subsurface parameters, specifically in karstic heterogeneous aquifers. This is particularly important in addressing the uncertainty of a 60‐day travel time capture zone in the Northwest Well Field, Miami‐Dade County, where a predominantly high flow zone controls much of the flow in the production wells. A stochastic ground‐water modeling application along with combination of pilot points and regularization technique is presented to further consolidate the uncertainty of the subsurface.     

Assessment of heavy metal status and identification of source in soils under intensive vegetable growing areas of Brahmaputra valley,North East India

Environmental Monitoring and Assessment - Evaporation is an important meteorological variable that has a great impact on water resources. In the current research, climatology data, and seasonal...