He spent $100 and counted 1,380 moth species

Doug Tallamy has spent about $100 turning his 10-acre Pennsylvania farm into a haven for wildlife over 26 years, mostly by pulling out invasive plants and dropping native seeds into the ground. He has since documented more than 1,380 species of moths there, along with 62 breeding bird species. When he and his wife Cindy bought the 300-year-old property in 2000, it looked green but held almost nothing. "There were no caterpillars," the University of Delaware entomologist recalls. That absence launched a movement. His nonprofit, Homegrown National Park, asks people to replace lawns with native habitat and register it on a national map. More than 52,000 participants have signed up, tending over 187,000 acres. His math is deliberately audacious: if just 10 to 20 percent of landowners planted natives, the result would top ten Yellowstones. He tours the country giving talks, and someone in the crowd has usually been dragged in by their neighbor.