The level of inflorescence predation was fairly constant at 

 Haynes Creek over the course of the study, and a significant 

 number of fecund inflorescences were produced in five of eight 

 years (Fig, 6) . At Sheep Corral Gulch there was evidence of 

 predation in years with and without evidence of livestock 

 grazing; however, predation was greater in years when livestock 

 were present. In 1993, 85% of the inflorescences were lost to 

 predation, and most of this predation was due to livestock (P. 

 Lesica, personal observation). 



Seed predation occurred at both sites in nearly every year 

 in which significant fruiting occurred (Table 1) . Overall, loss 

 of seeds to weevil predation ranged from 0-33% with a mean of 

 18%. Insect seed predation was generally higher at Sheep Corral 

 Gulch than at Haynes Creek (Table 1) . 



Table 1. Percent loss of seeds to insect seed 

 predators at two study sites. Sample sizes are given 

 in parentheses. 



1986 1988 1989 1990 1991 1993 



The combined effects of inflorescence and seed predation on 

 fecundity can be severe. In 1988 at Haynes Creek predation 

 reduced fecundity by 62%, while at Sheep Corral Gulch in 1993 

 fecundity was reduced by 90%. 



Elasticity 



Elasticity gives the proportional importance of demographic 

 transitions to population growth. Elasticities for five years of 

 transitions for the two study sites are given in Appendix C. 

 Columns of elasticities can be summed to give overall 

 elasticities for life history parameters (Silvertown et al. 1993) 

 Summary elasticities are shown in Fig. 7. Growth and survival of 

 non-reproductives was consistently important at both sites. 

 Survival of dormant plants was very important in two years at 

 Sheep Corral Gulch and one year at Haynes Creek. Survival of 

 reproductives and recruitment were important in about half of the 

 years. 



DISCUSSION 



Astragalus scaphoides is a long-lived perennial. Mortality 

 of seeds, seedlings and juveniles is high, but the majority of 

 plants that attain four years of age can probably expect to live 

 for at least ten years and perhaps much longer. The elasticity 



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