Tiller recruitment of perennial grasses in mixed-grass prairie primarily occurs from belowground bud banks. Environmental conditions, such as grazing and soil moisture regimes can affect the tiller recruitment and their dynamics of both native and invasive perennial grasses. Increased climate variability is likely to interact with other disturbances, such as grazing which may profoundly impact grassland community structure and function by affecting competitive dynamics between native and invasive species, and potentially undermining the effectiveness of restoration activities. The objective of this study was to compare tiller dynamics of native western wheatgrass (Pascopyrum smithii) and invasive smooth bromegrass (Bromus inermis) to main and interacting effects of clipping and soil moisture regimes under controlled temperature condition. A greenhouse experiment consisted of the combinations of three moisture regimes (VWC; 25%, 14% and 8%) and two clipping (clipping and no-clipping) with 240 replications for each species. Single-leaf seedling of each species transplanted in each individual potting-soil filled pot (16.5 cm diameter). Clipping treatments were applied at 2-leaf stage. New tiller was marked and recorded daily. Tiller recruitment data were analyzed. We found significant effect of soil moisture regime, species, and clipping (P<0.05) on total tiller number, relative tiller number, and tiller natality (tillers tiller-1 day-1) but no interactions. The weekly tiller recruitment was significantly higher for smooth bromegrass than western wheatgrass for both clipped or no-clipped treatments. Weekly percentage change in tiller number were significant for lowest soil moisture level. Further, weekly tiller recruitment of smooth bromegrass under low soil moisture level significantly lower compared to western wheatgrass in 4th and 12th week because of some difference in water stress tolerance. The results provide insight into the factors influencing vegetation dynamics of two important Great Plains grass species and will help for development of adaptive grazing management plans under predicted scenarios of climate change.
Oral presentation and poster titles, abstracts, and authors from the Society for Range Management (SRM) Annual Meetings and Tradeshows, from 2013 forward.