Riverine landscape dynamics of the Upper Ganga River (Haridwar-Narora), India

River dynamics - a geospatial analysis of Jamuna (Brahmaputra) River in Bangladesh during 1973-2019 using Landsat satellite remote sensing data and GIS

The present study is designed to illuminate the dynamics of the Jamuna River in Bangladesh for 46 years, from 1973 to 2019. About 240 km of the Jamuna River course was assessed using remote sensing and GIS. Landsat remote sensing imageries were processed, and bank lines were extracted and analysed using GIS. The main objective of the study was to understand the pattern of bed movement of the Jamuna River. The river dynamics were assessed based on bank erosion, accretion, bank line shifts, channel width, and river course and confluence shift. Area vulnerable to erosion was assessed using historical erosion rate and trend analysis. The result revealed that the river area increased by about 48% over 46 years. The total eroded area was about 1038 km², with 35.40% more erosion on the left bank than on the right. Due to higher erosion than deposition, the river widened. The average width of the river increased by about 56.40% during the period. The average rate of shifting was higher on the left bank than on the right, indicating the eastward movement of the river. Impact analysis showed that overall, a total of 822 km² and 390 km² of croplands and settlements were eroded during the period 1973-2019. The width of the confluence at the Padma River junction decreased by about 28%. The straight shift of the confluence was 9.27 km towards the southeast. The vulnerable area assessment anticipated that there would be more erosion on the left bank than on the right, and that Kurigram, Tangail and Jamalpur are the districts most susceptible to future left bank erosion. And, the lower reach of the right bank of the Padma River is at high vulnerable to erosion at the confluence. The methods and analysis adopted in this study can be applied to any other braided river to monitor the dynamics of the river and to formulate an action plan to protect the river from erosion.

A report on the butterfly (Lepidoptera: Rhopalocera) diversity of the Upper Ganga River Ramsar site in Uttar Pradesh, India

This study provides a primary inventory of the butterfly diversity of the Upper Ganga River Ramsar site in Uttar Pradesh, India. The study was carried out in two phases, first in March 2019 and then in November 2019. A total of 44 species of butterflies belonging to 34 genera and five families were seen in the area. The species observed in the study site belonged to the families Hesperiidae (4 genera, 4 species), Lycaenidae (4 genera, 4 species), Nymphalidae (18 genera, 24 species), Papilionidae (2 genera, 4 species), and Pieridae (6 genera, 8 species). Three of these species are legally protected under various schedules of the Indian Wildlife Protection Act (1972).

Variation of soil properties under different landscape positions and land use in Hunkuyi, Northern Guinea savanna of Nigeria

The food insecurity problem in developing countries has been linked to rapid rates of soil loss and decline in fertility in tropical environments which are characterized by insidious topography. This study was conducted to assess the relationship between topographic positions, land use, and soil characteristics. Three slope classes were considered with six pedons; two on each slope position were opened, described, sampled, and analysed for morphological and physicochemical properties. The results showed that the soils were deep to very deep with drainage improving from HK1 soils (very poorly drained) to HK3 (well-drained). The mean sand fraction ranged between 320 and 740 g kg^-1, while bulk density had values between 1.20 and 1.80 M gm^-3. The cation exchange capacity (CEC) of the soils with values from 5.6 to 10.4 cmol (+) kg^-1 was generally lower on the surface than the subsurface soils. The different landscape positions alongside variation in land use substantially influence variations in soil properties of the study area. The influence of topography was noticed for sand values and soil reaction (pH) along the slope, as mean pH values were significantly (P ≤ 0.05) higher for HK1 compared with HK2 and HK3. Intensive cultivation of soils due to rainfed and irrigated land use on middle slope position (HK2) alongside its strong slope gradient resulted in significant variation in total exchangeable bases (TEB) ((P ≤ 0.05), base saturation (P ≤ 0.05), available P ((P ≤ 0.01), and exchangeable Ca and Mg (P ≤ 0.05).