The Chitwan National Park is home to 92 percent of Nepal’s greater One-horned Rhino population. The latest rhino count of 2021 reports 694 out of 752 individuals. To sustain mega herbivores like the rhino, grasslands play an important role by balancing the natural ecosystem and providing food and shelter. The rhino, Tiger and the Bengal floricans and other species are thriving inside these grasslands, which support a large number of rare and endangered species. Grasslands help to maintain a balanced ecosystem in nature by providing nutrients and water, and also acting as carbon sinks.
In Chitwan, more than 50 grass species are documented by the Department of National Parks and Wildlife Conservation, including Saccharum ravennae also known as the elephant grass. The major species of Chitwan grasslands include varieties of Saccharum like Kans, Baruwa ghans, munja, narenga etc. Siru ghans, Themeda, Narkat, Masino narkat etc are other grass species here. Dubo, Kuro ghans, Love grass, Karaute ghans are smaller species less than 3m while Themeda and Narkat are tall grass species above 3m from the ground here. With its diverse forest, grasslands and wetlands areas, the park is rich in biodiversity.
During the 1970s, grasslands accounted for 20 percent of the total park area, which came down to 10 percent in four decades. Today, the grassland inside the core area is only 9.61 percent and in the buffer it is 2.06 percent of the total buffer area. Park officials and the national park department have documented 425 grassland patches with a total area of 10497.2 hectares where the core area has 8955.2 hectares covered by grasslands. Among the documented patches, 20 grasslands patches exceed an area above 100 hectares while 106 different patches have an area between 2-5 hectares today. Increase of woody vegetation and invasive species has caused the grasslands inside the park to shrink.
Increasing anthropogenic activities and habitat shrinkage has led to habitat degradation, which demands immediate action for restoration. Siru and Kans are invaded by woody species while anthropogenic and biological invasion has caused the habitat to degrade in the park. Restoration practices help to transform those degraded grasslands.
A yearly report from the park has mentioned that conversion of grasslands and shrubland and then shrubland to forest is another cause of shrinkage of grasslands in western and southern parts of the park. The floodplains are mainly colonized by mixed riverine forests of khayer and Sissau. However, riverine tree species like Vellar, Simal, Jamun, Kyamuna and Sindure are also associated with the lowland grasslands.
To enhance the reduced grasslands, habitat restoration is the best immediate and long-term action to sustain the balanced ecosystem. Restored habitat can contribute to rhino movement activities inside the parks. For example, grasslands in Chhaparchuli, Gundremundre, Milijuli, Janakauli, Chitrasen, Chhapar Chhuli Road site clearance, Jayamangala, Bankatta, Arna enclosure, Marchauli, Patana Marsh, Hattikhet, Gaur Machan, Dumariya Post, Simal Ghole, Kachuwani Machan and other sites of the park areas are under the management of National Trust for Nature Conservation(NTNC) in close collaboration with CNP from 2021 to 2024. This has had a positive impact on animal movement in those areas. The park’s yearly report mentions that NTNC has managed more than 500 hectares of grassland during the last two fiscal years.
The degraded grassland has been restored after systematically removing the invasive species. The restored habitat showed a good result with suitable grazing lawns for the herbivores. With support from the International Rhino Foundation (IRF), NTNC has succeeded in creating a fresh grazing lawn. Previously 104 rhinos were counted in those areas; now their number has reached 172 according to the recent internal monitoring of Rhino by NTNC technicians. The improved habitat conditions for rhinos has also benefited other wildlife, including tigers, leopards and herbivores such as sambar and gaur.
Combating invasive species
The spread of invasive species like Mikania micrantha, Lantana Cammara and dense growth of tall grasses such as Saccharum spp and Phragmites karka have further reduced available grazing space to the herbivores. Invasive species prevents rhinos from accessing nutritious forage thereby decreasing the quality of grasslands. This has led the species to compete with limited resources ultimately increasing the risk of intraspecific fights. To overcome this problem, two approaches were adopted for removing these weeds. Mechanical cutting using specially equipped tractors and manual uprooting of invasive species.
Mechanical cutting provides the systematic approach to control the height of dominant species while manual removal allows for targeted management of specific areas. This strategy has shown a positive impact in maintaining open grazing lawns, thereby increasing the species regeneration. With this activity, enhanced habitat quality has also facilitated the presence of apex predators like tigers and leopards alongside the dispersal of sambar and gaurs within the intervened areas.
Camera trap survey and ID base rhino tracking has been carried out within the managed grassland, which has confirmed the rise in rhino occupancy in the restored habitat. The camera traps survey helped monitor the animal movement, distribution and population dynamics with the response to grassland management activities. Management interventions in Padampur, Icharni and Chhaparchuli areas have helped to increase the habitat suitability for rhinos but also for other herbivores. Increasing the biomass of palatable grasses also plays an important role in reducing the nutritional stress and associated mortality in the rhino population.
The grass cutting was implemented biannually-during winter months (Jan-March) and again in the pre-winter (Oct-Dec) across all intervening habitats. The increased presence of herbivores in the restored areas has attracted apex predators. Camera trap data from the Icharni and Kumrose regions confirm an increase in tiger and leopard activity indicating a healthy ecosystem in the intervention area. The connection between habitat management and predator movement is interlinked. To sustain both rhinos and tigers in Chitwan, investment in habitat restoration is crucial.
Communities against threats
Long-term conservation success requires continuation of habitat management activities which demands community participation. In this intervention, NTNC engaged Buffer Zone User Committees (BZUCs) and local communities in grassland management. During the manual removal of invasive species, local people get alternative livelihoods. This not only benefits wildlife but also helps to gain community support in conservation.
However, the threat still exists. March-April is the season of forest fire in most parts of Nepal. People burn the grass with the expectation of new palatable grass shoots during this time, but it has created destructive problems in many parts of forest and buffers due to lack of controlled measures. However, early fire during winter helps to promote nutritious new sprouts of grasses. Uncontrolled grazing of livestock can create foraging grass shortage which may lead to conflict.
Grasslands are also threatened by several other reasons including infrastructure development and wetlands construction. Haphazard construction of buildings, roads etc not only reduces and degrades the grassland habitat but also has far-reaching effects through colonization of invasive weeds and degradation of ecosystems. Introducing new cutting-edge technology helps to timely remove weeds.
Healthy grasslands
Studies on the species composition and periodic monitoring of grasslands are necessary for a healthy grassland ecosystem. Also, seasonal flooding during the monsoon limits the window for habitat management. If we want to re-establish native species in the areas we need a continuous intervention for grassland management. Additionally, human-wildlife conflict is a major issue where some rhino deaths are linked to electrocution and poaching. To these efforts, rhinos of Chitwan have a better chance of survival if such interventions continue.
At the same time, climate change has altered the habitat and is a major issue of water scarcity. This demands additional interventions like construction of waterholes, climate-friendly infrastructure, research and outreach activities inside the area. Managing wetlands is another important factor for the creation of a healthy and balanced ecosystem.
The author is a conservation officer at the National Trust for Nature Conservation
