Since the colonial era, India has regarded its native savannas as little more than degraded forests. Now, amid a growing recognition of rangelands globally, officials are working to map the nation’s ailing grasslands, with a view to restoring these vital ecosystems.

It’s almost noon, and the sun is high over Gulunche, a village in the western Indian state of Maharashtra that is surrounded by sugarcane fields, grassy pastures, and short trees. The landscape appears verdant, but it belies an ecological precarity. The sugarcane guzzles water in the semi-arid terrain; a dominant tree species is a South American mesquite, introduced decades ago to fight desertification and provide firewood; and the grass itself has been overrun by a single species that provides poor fodder for the wild herbivores and sheep that depend on these pastures.

Standing on the edge of a small nursery off the highway, conservationist Mihir Godbole points to rows of tall green grasses growing at the edge of a trench.…