The Nieman Foundation for Journalism yesterday announced the appointment of 12 American fellows to begin one year's study at Harvard this fall.

The list of fellows includes the first cartoonist the foundation has chosen, Douglas N. Marlette, an editorial cartoonist at the Charlotte Observer. In past years, the foundation has selected "a few journalists who could draw cartoons, but never a cartoonist," Tenney K. Lehman, editor of Nieman Reports, said yesterday.

A committee of professors and journalists made the decisions last month and will announce the foreign journalists during the summer. The selection committee, which changes every year, chooses journalists who have at least three year's full-time experience. A bequest from Agnes W. Nieman established the fellowships in memory of her husband Lucius W. Nieman.

The new fellows are

* Frank G. Adams, Helena bureau chief, Great Falls Tribune;

* Carlos Aguilar, reporter for KENS-TV in San Antonio, Texas;

* Peter J. Arnold, reporter, Cleveland Press;

* Gerald M. Boyd, Washington reporter, St. Louis Post-Dispatch;

* Rose M. Economou, producer, WBBM-TV in Chicago;

* Michael E. Hill, Style editor, The Washington Post;

* Davis S. Lamb, Nairobi, Kenya, bureau chief, The Los Angeles Times;

* Laurel Shackelford, assistant city editor, The Courier-Journal in Louisville, Ky.;

* Howard S. Shapiro, reporter, The Philadelphia Inquirer;

* James D. Stewart, reporter, The Atlanta Constitution;

* Nancy C. Warnecke, photographer, The Tennessean, and Marllette.