Propagation and production of an endangered aquatic macrophyte: Texas wildrice (Zizania texana Hitchc.)

Abstract

Texas wildrice (Zizania texana Hitchc. [Poaceae]), a federally endangered aquatic macrophyte, is propagated from seeds (grains) and tillers at the USFWS’s San Marcos Aquatic Resource Center (SMARC) for supplementing natural populations in the San Marcos River and life history studies at SMARC. I found seeds to be more efficient and cost-effective compared to using tillers because of the amount of space required for maintaining tillers and the time required to collect wild tillers from the San Marcos River. Seed germination was 67% for 44 germination trials and seedling survival was 88% (n = 9413) from 2012 to 2014. Growth rates based on total leaf length were 3875 cm (1525 in) at a flow of 0.4 m/s (1.3 ft/s) compared with 1069 cm (420 in) at 0.0 m/s. Texas wild seeds grown in a flow of 0.4 m/s (1.3 ft/s) can be planted in the San Marcos River at 10 to 12 wk post-germination. Outplanting of Texas wildrice in the lower San Marcos River resulted in a 4-fold increase in area coverage at 8 mo post-planting compared to initial planting at 0 mo.