In 1978, Texas wild-rice was the first plant in Texas to be listed as endangered by the U.S. Fish and Wildlife Service. It is a perennial, emergent, aquatic grass presently known only from the upper 2.5 km of the San Marcos River.
Recreation poses an unknown degree of threat to Texas wild-rice.
Due to its extremely limited distribution and location in a heavily used river, many popular activities such as tubing, swimming, boating, and fishing could impact the rice. During 1996, volunteers contributed 446 observation hours to help TPWD record data at six transects located between Spring Lake and the IH-35 bridge. The final report will provide a summary of recreational contact with wild-rice and describe management strategies towards alleviating existing or potential stresses.