Diversity, distribution and vegetation assessment in the Jahlmanal watershed in cold desert of the Lahaul valley, north-western Himalaya, India

Relict vegetation in the Jahlmanal watershed is sparsely and scantily distributed on forest land. Farmers maintain tree species (Salix spp., Populus spp., Hippophae rhamnoides) on the boundaries of terraced agriculture fields to meet the fodder and fuel wood requirements. Juniperus macropoda was found in relict forest patches in sparse and stunted conditions. The density of Salix fragilis was 3340 trees ha-1 under agroforestry and 5520 trees ha-1 under forestry. The density of J. macropoda was 4200 tree ha-1 in natural forest followed by 700 tree ha-1 in agroforestry and 160 tree ha-1 in managed forestry systems. The agroforesty system of the watershed consists of 30% trees, 35% small trees and 35% shrubs species. Shrubs contributed the highest density with 59.1% of the total, followed by density of trees (29.5%) and small trees (11.3%). Trees contributed highest basal area in all the three systems, i.e., agroforestry, forestry and forest. The relict forest patches are subjected to deforestation due to anthropogenic pressure, hence in-situ and ex-situ conservation are required. Efforts are needed for plantation of ecologically suitable multipurpose tree species with indigenous species in the watershed. Technological interventions are also required to improve the quality and resistance against drought and climate change

Identification of groundwater contamination zones and its sources by using multivariate statistical approach in Thirumanimuthar sub-basin, Tamil Nadu, India

Hydrogeochemical studies have been made in the study area by using multivariate statistical analysis, which is mainly helpful for interpretation of complex data matrices to better understand the geochemical evolution of the area and it allows identifying the possible factors/sources that influence water systems. The spatial distribution of electrical conductivity reveals that an untreated industrial effluents, landfill and anthropogenic activities affecting their groundwater quality in its vicinity and the surrounding area. The dominance of ions was in the order of Na+ > Ca2+ > Mg2+ > K+ = Cl− > HCO3 − > SO4 2− > NO3 − and Ca2+ > Mg2+ > Na+ > K+ = HCO3 − > Cl− > NO3 − > SO4 2− during pre monsoon (PRM) and post monsoon (POM), respectively. The statistical results reveals that the groundwater chemistry gets altered by silicate weathering, ion exchange, leaching, anthropogenic input from agricultural return flow and longer distance of migrating groundwater. The hydrogeochemical regimes are distributed along the upstream side, northwestern, western and eastern parts of the study area. The study highlights the descriptive capabilities of conventional and multivariate techniques as effective tools in groundwater evaluation