SEED PRODUCTION, SEED RAIN, AND THE SEEDBANK OF FRINGED SAGEBRUSH

Increases in fringed sagebrush (Artemisia frigida Willd,) following di sturbance on Northern Mixed Prairie are due to enhanced growth of esta blished plants and seedling recruitment, The roles of seed production and the soil seedbank in population dynamics of fringed sagebrush foll owing disturbance are, however, unknown, Furthermore, seed rain has no t been documented for this species, The objectives of this study were to determine: 1) the effect of disturbances in the sward on seed produ ction; 2) relationships between the soil seedbank and current seed pro duction; and 3) seed rain over time for fringed sagebrush, Disturbance s of clipping, litter removal, tillage, and a combination of clipping and litter removal were imposed on a sandy range site in central Saska tchewan, Following disturbance seed production plant either increased or was unchanged compared to the undisturbed control, Greater seed pro duction resulted from increased production of seeds head(-1), heads in florescence(-1) and inflorescences plant(-1), The timing of seed rain varied considerably among individual plants, Five temporal patterns of seed rain were identified for individual fringed sagebrush plants: 1) 5.2% of the plants began and completed dispersing seeds within 6 to 8 weeks of powering; 2) 20.8% began dispersing within 6 to 8 weeks of f lowering and completed dispersal before snow was received in autumn; 3 ) 37.7% began dispersing seeds within 6 to 8 weeks of flowering and co ntinued over the winter; 4) 29.9% delayed dispersal of seeds more than 8 weeks after flowering and continued over the winter; and 5) 6.5% be gan and completed seed dispersal during the winter, The number of frin ged sagebrush seeds in the soil was correlated with seed production on ly when many seeds were produced (r = 0.76), indicating that annual se ed production is of limited importance for maintaining a seed-bank. A persistent seedbank is important in maintaining fringed sagebrush popu lations when seed production is limited. Diverse rates and times of se ed rain along with a persistent seedbank may enable fringed sagebrush to occupy safe sites that develop in time.