A memorial gathering for Robert Dash, the founder of the Madoo Conservancy in Sagaponack, who died in September, will be held there on Sunday at 5 p.m. Several of Mr. Dash’s friends will speak, and afterward clams and Bloody Marys will be served in his honor. Those attending have been asked to let Alejandro Saralegui, the conservancy director, know in advance by phoning the Madoo office or emailing [email protected].