Butterflies are in peril. Here’s what we can do.

Butterflies need our help.

During the past four decades, scientists have documented a 1.6 percent decline per year in the number of butterflies in the southwestern United States.

Doesn’t sound like much? Consider how that figure compounds over the years.

“This means that since 1977, scientists have observed a whopping 64 percent drop in butterfly numbers, which comports with my own childhood memories of butterflies in Southern California,” says Adriana Briscoe, distinguished...