Jasper County, S.C., along the coast, has seen a crush of newcomers in recent years, drawn by its proximity to beaches and low taxes. Locals fear they may be losing their rural way of life.

Jasper County is awash in wetlands and teeming with wildlife. Turkeys amble near piers and marshes. Locals take small boats and traverse through salty estuaries that nurture oysters and spotted sea trout. The land also serves as a natural buffer during storms, which have intensified in recent years because of climate change, said Jessie White, a lawyer with the South Carolina Environmental Law Project.