In a landmark judgment, Sri Lanka’s Supreme Court recently ended a 15-year legal battle over plans to upgrade a road through Wilpattu National Park, making conservationists heave a sigh of relief.

Previous studies have found that the better-known Yala National Park in Sri Lanka’s south, popular for its leopard sightings, has about 54 leopards per 100 km2 (140 per 100 mi2); Wilpattu ...