Population Dynamics of Trifolium balansae and T. Resupinatum in self- Regenerating Pastures. II. Predicting Long-Term Persistence from a Demographic Model

1. Trifolium balansae and T. resupinatum are new to self-regenerating pastures. Little is known about the mechanisms whereby these species would be able to persist in pastures. 2. A model, based on data obtained from field measurements, was used to predict the persistence of T. balansae cv. Paradana and T. resupinatum lines SA 12240 and SA 14433. 3. This model showed that T. balansae cv. Paradana could persist in pastures in central west New South Wales, Australia, whereas T. resupinatum lines SA 12240 and SA 14433 could not. 4. Seed production was the most important factor determining persistence; all lines could be made to persist or fail by changing seed production. 5. SA 12240 could persist if plant recruitment increased from 14% to more than 30% or plant survival from 23% to more than 48%, or by an increase in seed production. SA 14433 was the least successful line and could only persist by an increase in seed production.