CHARLESTON, S.C. (AP) — A plan to preserve the culture of slave descendants of the sea islands on the Southeast coast has been approved by the Department of the Interior.

The 272-page management plan for the Gullah-Geechee Heritage Corridor has been more than a dozen years in the making.

Last week's approval means the corridor commission can move ahead with the plan that envisions preserving significant sites and putting up signs to direct visitors. The next steps will be discussed Friday at commission meeting in Conway.

The culture is known as Gullah in the Carolinas and Geechee in Georgia and Florida.

In past years it survived in many areas untouched because of the isolation of the sea islands. But now the culture and many sites important to it are threatened by coastal development.