Assessment of wildlife values of the Ganga river from Bijnor to Ballia including Turtle Wildlife Sanctuary, Uttar Pradesh

Abstract

Freshwater ecosystems, especially riverine systems, give rise to unique habitat mosaics, which support distinctive biodiversity and provide substantial ecosystem services, creating a strong imperative for their protection and restoration. They are being impacted globally by divergent but frequently concurrent processes including water pollution, over-fishing, alteration of natural flow regime, invasive species, climate change and human-induced habitat loss. These dynamic systems are often poorly protected, and require conservation measures through systematic planning. Systematic Conservation Planning (SCP) is widely considered as the most influential paradigm to identify and bring areas under protection through effective planning and spatial prioritization. The SCP requires an evaluation of sites for their biodiversity values, habitat heterogeneity, habitat dynamics, and existing human-induced habitat alteration factors. The Ganga River is the lifeline to more than 500 million people as it flows through five riparian states. It also harbours a unique assemblage of biodiversity due to its passage through three distinct biogeographic zones and unique habitat mosaics. Apart from nurturing umbrella species like the Gangetic river dolphin, otters, gharial and muggel; the Ganga River basin is recognized as a Global Turtle Priority Area and a Turtle Biodiversity Hotspot. With the aim of protecting and consel1'if7g the diverse array of biota and their habitats, a 7 km stretch of the Ganga River between Rajghat (Malviya Bridge) to Ramnagar Fort in Varanasi District, Uttar Pradesh was declared as the Kachhua Vanyajiv Abhyaranya (Turtle Wildlife Sanctuary - TWS). Although declared a protected area, increase in riverbank agriculture, river traffic, water pollution through sewage and solid wastes are posing a threat to the biodiversity of TWS and the river-riparian habitats. High human disturbance in the form of cultural-religious activities are influencing the biological values of TWS. Considering the above, a rapid assessment study (March- July, 2018) was conducted in the TWS to evaluate its efficacy as a protected area; and to identify areas for effective biodiversity conservation. Stretch of the Ganga River between Bijnor to Ballia in Uttar Pradesh was evaluated following Systematic Conservation Planning approach. The objectives of this study were (1) Assessment of habitat structure of TWS and to detect changes over time, (2) Evaluation of efficacy of TWS and adjoining riverscape as a refugia for species of conservation concern; and (3) Prioritization of the Ganga River stretches with mosaics of riverine habitats for conservation planning. A spatial assessment using remote sensing data for the period 1974 to 2016 revealed no significant changes in river channel and sand deposition in the TWS. However, -28% increase in the vegetation cover was observed which could be attributed to the protection accorded to the riparian areas by the Forest Department compared with an expansion of agricultural areas on the landward side. Out of 13 species of turtle reported from Ganga River, only 5 species were encountered during the field sampling with the combined efforts of visual encounter surveys and in-stream sampling using gill nets and box traps within the TWS and upstream and downstream of the Sanctuary limit. Very low encounter rate of turtles in TWS indicates high human disturbance leading to habitat alterations within a very small Protected Area. Sites along the TWS in the left bank are seen to have the least suitable habitat for turtles with high anthropogenic disturbances such as cemented ghats, intense ferry and boat activity, pollution, and human presence along the river. The sand bar in the right bank of the TWS, though is an excellent habitat for turtles and breeding birds, is also under severe anthropogenic pressure. Out of64 species offish reported/rom the Middle Ganga stretch. a total 0/45 species belonging to 38 genera, 16 family and five orders were recorded during the sampling period. The fish catch was higher inside TWS as compared to upstream and downstream o/the sanctuary and this could be attributed to prohibition o/fishing within the Sanctuary limits. A total of28 species of birds were observed, of which four species were of threatened categories as per the IUCN Red List. Nests of breeding birds were not observed from the TWS due to high biotic disturbance. A nesting site of the Indian Skimmer was identified at approximately 6 km upstream of the Sanctuary. Five pairs of Indian Skimmer and 14 pairs of Little tern, 4 pairs of River Lapwing a Near Threatened Species were observed/rom the vicinity. A rapid assessment of wildlife values was conducted in the entire stretch of the Ganga River falling within Uttar Pradesh and priority areas were identified through a scoring matrix. Kruskal's Multidimensional Scale analysis described the habitat parameters that influence species distribution. These parameters were sand mining, channel depth. fishing activities, presence of village/town and riverbed agriculture. Channel depth is the only factor which is positively influencing species distribution. Based on the scoring matrix, the highest biological value was attributed to a river stretch within the Hastinapur Wildlife Sanctuary, followed by the stretch from Brijghat to Narora, which is notified Ramsar Site. In addition to these, moderate biological value was assigned to the stretch downstream of Newada till Ballia. Habitat characteristic score (channel depth, meanders and river islands) was high in the downstream of Allahabad, till Ballia as this stretch persistently maintains high depth classes, meanders and river islands representing a complex mosaic of habitats. The anthropogenic influence scores was almost similar in the entire stretch from Bijnor barrage to Ballia as the river bed agriculture was prominent in the upper stretch. whereas fishing, sand mining, and human settlements were prevalent in the lower stretch of the river. The stretch between Hastinapur Wildlife Sanctuary and Narora already enjoys the protected area status. In spite of the protected status, TWS scored low due to its small size and high human disturbance. Based on the combined scores, a 140 Ian stretch downstream Newada in Allahabad district to Adalpur in Mirzapur district has been considered as the priority stretch for conservation. It is suggested that this area may be brought under the purview of Wild Life (Protection) Act, 1972 by declaring it as a wildlife sanctuary for the conservation of aquatic biodiversity of the Ganga River in Uttar Pradesh. Since the ecological characteristics and wildlife values vary along this 140 Ian stretch on account of anthropogenic pressures, harmonization for excluding some areas having high anthropogenic pressures on account of intense cultural-religious uses may be required, and to be done by the Uttar Pradesh Forest Department.