THE BIG PICTURE

FRAGILE, DUNE-LAKE ECOSYSTEMS are very rare. They are found in a handful of destinations worldwide, one of which is Grayton Beach on Florida’s Panhandle. The shallow-bodied freshwater lakes formed thousands of years ago are filled by wind-driven tides and rainwater and flushed with saltwater from the Gulf of Mexico. Slender dune lines buffer one body of water from another. On this beachfront, a family of six built a second vacation home along a famed stretch of Walton County’s scenic beach road, Highway 30A.

Homeowner Cheryl Hix had been interior designer Janet Taylor’s first client, and in an ironic twist became her last before she retired. “She sold the first house to build this one beside it …