Guwahati: Proper management of woodland and grassland habitats at the Pobitora Wildlife Sanctuary (PWS), which has the highest density of Indian rhinos in the world, is of utmost necessity at this moment, a remote sensing study says.
A study using remote sensing and GIS to detect the rhino habitat change, the impact of invasive species and the rhino habitat suitability status of Pobitora shows an increase in woodland from 44.74% in 2008 to 54.71% in 2020, accompanied by an increase in alluvial grassland from 21.36% in 2008 to 23.71% in 2020.
“The transformation of wildlife habitat in Pobitora WLS is largely because of the natural succession process, massive flood in 2004, along with impacts of invasive plant species, local livestock grazing and proper grassland habitat management,” says the study by Pranjit Kumar Sarma of Mangaldai College, Bibhab Kumar Talukdar of Aaranyak, Pradipta Baruah and Mukul Tamuli of Assam Forest Department.
Pobitora Wildlife Sanctuary (WLS) is a prime habitat for Greater One Horned rhino (Rhinoceros unicornis). With a population of 102 rhinos as of 2018, Pobitora has the highest density of Indian rhinos in the world. The satellite images of 2008, 2013, 2016 and 2020 have been analysed to understand the changes in the rhino habitat in Pobitora WLS.
The results reflect a substantial increase in woodland from 17.36 sq km (44.74%) in 2008 to 20.11 sq km (51.82%) in 2016. This growth trend continues till 2020 and has risen up to 21.23 sq km (54.71%). The trend of growth of woodland continues from 1977 onwards. This shows that a total of 10.13 sq km (26.10%) of woodland habitat has increased in Pobitora WLS from 1977 to 2020.
“This growth of woodland is mainly due to the natural succession from grassland to woodland. If this succession continues, it can adversely affect the quantum of grassland habitat needed for rhinos in this WLS,” the study found.
The most positive and remarkable change observed through this study is the growth of alluvial grassland. “The trend of growth of alluvial grassland was negative from 1977 to 2004. In 1977 the total area covered by alluvial grassland was 16.25 sq km (41.80%) which reduced to 5.2 sq km (13.37%) in 2004. But from 2008 to 2020, there is positive growth of alluvial grassland in the sanctuary. In 2008 the total area covered by alluvial grassland was 8.29 sq km (21.32%), and in 2020 it rises up to 9.2 sq km (23.71%). This positive growth is mainly due to the impact of a massive flood in 2004 and the proper management of alluvial grassland in the sanctuary by the authority,” the study says.
Another important change observed through this study is that there is a decreasing trend of dry grassland habitat in the sanctuary from 2004 to 2008 and until 2020. In 2004, the total area covered by dry grassland was 6.51 sq km (16.74%), which reduced to 4.29 sq km (11.05%) in 2020. This decrease in dry grassland is mainly due to the increase of alluvial grassland habitat in part and the increase of invasive species like Ipomoea, Mikania, Chromolaena, which are commonly seen on roadsides and dry places in the sanctuary.
A habitat suitability model has also been prepared, which shows that only 35.11% (13.62 sq km) area of the sanctuary is highly or moderately suitable for 102 rhinos available in Pobitora WLS. The rhino habitat suitability status of the sanctuary is also not up to the mark, as only 6.49% of the total geographical area is highly suitable in the sanctuary.
“The result shows that 5.42% (2.1 sq km) of the total geographical area of the sanctuary is highly suitable for rhinos. The moderately suitable area covers 29.69% (11.52 sq km) of the sanctuary. Most interestingly, 64.89% (25.18 sq km) of the total geographical area of the sanctuary is less suitable for rhinos in the Pobitora WLS,” the study says.
“Habitat management is very crucial for the future of Pobitora wildlife sanctuary. Cattle grazing from neighbouring areas is another big concern,” Pranjit Kumar Sarma of Mangaldai College, the corresponding author of the study, told EastMojo.
“The growth of invasive plant species is a significant threat to rhino habitat in the sanctuary, which have remained not as visible as rhino poaching. The long-term application of efforts alongside constant monitoring and investigation is required to handle this problem,” the study says.
Bibhab Kumar Talukdar of Aaranyak says further research is going on at Pobitora. “We shall be able to offer specific recommendations for habitat management in one year’s time,” he said.
The study suggests measures should be taken to convert the moderately suitable habitat into highly suitable habitat in the sanctuary, and a proper understanding of hydrology flow in and around WLS may add value to further improve rhino habitats in the WLS.
“To achieve this goal, scientific habitat management practices should be adopted as early as possible. Like any other national park or wildlife sanctuary, even Pabitora WLS is also surrounded by human habitation. The authorities should take necessary action to protect the wildlife habitat from the other domestic grazing animals like cows, goats and buffaloes,” the study says.
Dear Reader,
Every day, our team at EastMojo travels through rain, rough roads, and remote hills to bring you stories that matter – stories from your town, your people, your Northeast.
We do this because we believe in truthful, independent journalism. No big corporate backing, no government pressure – just honest reporting by local journalists who live and breathe the same air you do.
But to keep doing this work, we need you. Your small contribution helps us pay our reporters fairly, reach places others ignore, and keep asking the tough questions.
If you believe the Northeast deserves its own fearless voice, stand with us.
Support independent journalism. Be a Member.
Thank you,
Karma Paljor
Editor-in-Chief, eastmojo.com
The study recommends forming Eco-Development Committees (EDCs) in and around the WLS. The EDC should prepare the micro plan for their respective villages where conservation actions can be linked to their sustainable livelihood by reducing the gap between the sanctuary authority and the local community.
“This will stimulate the rhino conservation efforts in the sanctuary collectively,” it says.
Also read | Assam engineers’ forum lauds HC order on electricity safety measures