CAREX KOBOMUGI (JAPANESE SEDGE) AN INTRODUCED DUNE PLANT NOW GENUS NON GRATA: MANAGEMENT ISSUES IN STATE AND FEDERAL PARKS

Carex kobomugi (Japanese Sedge) occurs naturally along the coastal dunes of Japan, Korea, Russia and China, where it forms small dunes, sometimes within 50 meters of the higher tide line. First identified in North America near Island Beach State Park (NJ) in 1929, it probably was accidentally introduced from shipwrecks containing barrels of Oriental porcelain where it was used as packing material. At once identified as a plant that could be beneficial in dune building, it has, or was spread experimentally from Massachusetts to North Carolina where it occurs in diverse habitats from sand pits to the rip-rap adjacent to Chesapeake Bay Bridge Tunnel. Half as tall as its co-inhabitant Ammophila breviligulata (American Beachgrass), with droopy, even curly, sharp leaves, C. kobomugi builds lower dunes, but in dense stands can form a mat with as many as 200 plants/sq.m. effectively crowding out A. breviligulata.

Studied in the late 1980s by NJDEP as a potential alternative to A. breviligulata since it appeared more resistant to tramping in such areas as dune paths, and populated the back dune area where beachgrass died out, C. kobomugi was very difficult to propagate, the survivorship of the transplanted culms was very low but some researchers considered it naturally competitive. Since it is considered an exotic species due to its introduced nature, and could not be propagated easily, further research by the NJDEP was not continued. Now with more attention to the eradication of exotic species by the state and federal governments, the NJ stands of C. kobomugi are facing aggressive eradication efforts. Without the knowledge of its propagation style, and alternative plants to fill the acres of Carex-less back dune areas, the NJ Extension Program has begun to study possible alternatives in order to recommend management strategies to avoid producing further problems such as back dune blowouts and movement of sand into unwanted areas.