Effects of timed mowing to control Taeniatherum caput-medusae in an annual grassland

Medusahead grass (Taeniatherum caput-medusae) has been introduced to grasslands in eight states in the U.S. and has severely impacted biodiversity and rangeland productivity in invaded areas. The effectiveness of timed mowing on seed development as a means to control Taeniatherum invasion and favor more desirable species was examined in an annual grassland community. Baseline species composition was collected in a grassland invaded by Taeniatherum prior to assignment of three management treatments: no mowing (control), one time mowing, and repeated annual mowing (n = 10 per treatment). The average cover of Taeniatherum in the field based on combined baseline values for all plots was 87.97% (±18.05, n = 30). In addition to monitoring community consequences, effects of the treatments on development of viable Taeniatherum seed was assessed by inspecting florets collected at the time of treatment for developing seeds. At the time of treatment, florets in the mowed treatment group had 0.8 % (±1.79) of florets with developed seeds while the control group contained 90% (± 5.39) florets with developed seeds (P< 0.0001). Thus, less prevalence of fully developed seeds in the mowing treatment group demonstrated the effectiveness of this management approach on interrupting seed development of an invasive and low quality forage grass.