Why Removing Trees Helps to Save the Greater One-Horned Rhino

Manas National Park in Assam, India, the northeastern state that holds the largest population of greater one-horned rhinos, is a breathtaking grassland ecosystem of global importance. The Park is home not only to greater one-horned rhinos, but also to Asian elephants, gaurs, wild buffalo, tigers and the critically endangered Bengal florican (with approximately less than 1,000 individuals remaining worldwide) and pygmy hog (fewer than 300 individuals left). This landscape is more than a wildlife sanctuary; it is a vital ecosystem that sustains both biodiversity and neighboring communities, many of whom depend on wildlife tourism and community-based livelihood projects.

Yet Assam’s remarkable grasslands are under threat. For years, Manas has been encroached upon by invasive plant species such as Chromolaena odorata, a fast-growing woody perennial shrub, as well as aggressive native trees like Bombax ceiba. Chromolaena, native to the Americas, is considered one of the most invasive plant species in India. It spreads rapidly, forming dense mats that block sunlight and smother native vegetation. Although Bombax trees are native to the region, they multiply aggressively, overtaking open grasslands and crowding out the native grasses that wildlife depend upon for food and habitat.

While it may seem counterintuitive to remove trees and vegetation as part of a conservation strategy, such interventions are essential components of habitat and species management in Manas. The International Rhino Foundation (IRF) has long supported the work of the Indian nonprofit Aaranyak, whose team of scientists and conservation practitioners study wildlife and actively manage the park’s grasslands. Their work involves a range of labor-intensive techniques to remove unwanted vegetation and restore ecological balance. The work is conducted by local people, providing regular employment for communities that live on the outskirts of the Park, building awareness about conservation needs and ownership of the projects. The local people have become excellent advocates for this work.

Removing Chromolaena is even more challenging. Fire, which is sometimes used in grassland management, actually stimulates stronger regrowth of this invasive shrub. Because the Park does not use herbicides, manual removal is the only viable solution. Workers must painstakingly pull the plants by hand, ensuring that all roots are removed to prevent regeneration. Given the vast spread of Chromolaena throughout the park, the task can feel overwhelming.

Despite these challenges, the restoration of Manas’s grasslands is critical to the survival of its iconic wildlife and the well-being of surrounding communities. Protecting this ecosystem requires sustained commitment, scientific expertise and hands-on labor. It also requires financial resources, and IRF is grateful to our many donors who support this important program. By controlling invasive and aggressive plant species, conservationists are not working against nature—they are acting as its stewards, carefully restoring the balance that allows grasslands, wildlife and people to thrive together. In safeguarding Manas National Park today, they are securing a future for some of the world’s most endangered species and preserving one of India’s most extraordinary natural landscapes for generations to come.