Vegetative reproduction as a stabilizing feature of the population dynamics of Yucca glauca.

The life history of Yucca glauca in the Great Plains was the subject of a four year field study. Data were incorporated in a stage transition model (based on rosette size) to explain how populations are maintained in spite of large regional and temporal variation in sexual reproductive success. Rosette size was found to be a good predictor of flowering effort, but a poor predictor of fruit set. Large rosettes that failed to set fruit, however, exhibited an increased capacity for vegetative reproduction. Asexual reproduction contributes to population stability by reducing the variance in annual recruitment, and perhaps by damping oscillations caused by departures from a stable stage distribution.