The Rediscovery and Status of Dissanthelium californicum (Poaceae) on Santa Catalina Island, California

Abstract

Dissanthelium californicum (Nutt.) Benth. (Poaceae) is an annual grass known only from Santa Catalina and San Clemente Islands, off the coast of Southern California, USA, and Guadalupe Island, off the coast of Baja California, Mexico. It had not been recorded since Blanche Trask collected it in 1903 on San Clemente Island, and was therefore considered to be extinct, possibly as a result of overgrazing by introduced goats on these islands. During monitoring by the Catalina Island Conservancy from March through July 2005, D. californicum was discovered growing in seven diverse and widely spread locations on Santa Catalina Island. The rediscovery may be a result of the removal of feral goats and pigs from the island, record-breaking rainfall, and increased exploration of remote areas. A revised description of the species and a summary of its habitat preferences are provided. Thorough monitoring and surveying of known and potential locations will be necessary to better determine the conservation status of the species.