proportion of fecund inflorescences increased, the proportion of 

 aborted inflorescences decreased (Table 4). There was a weak 

 negative correlation between proportion of inflorescences that 

 were aborted and those that were predated (Table 4). There was 

 no correlation between proportion of predated inflorescences and 

 proportion of fecund inflorescences or total inflorescences 

 (Table 4) . 



Climate and Life History 



Increased mortality of Astragalus scaphoides was associated 

 with low fall and winter precipitation, low summer temperatures, 

 high spring and summer precipitation, and high fall temperatures. 

 High recruitment was associated with high fall temperatures, low 

 spring temperatures and low summer precipitation. Proportion of 

 reproductive plants was negatively correlated with spring and 

 summer precipitation. 



DISCUSSION 



Astragalus scaphoides is a long-lived perennial with a 

 cohort half-life of approximately six years. Mortality is 

 relatively high during the first two years and is lower 

 afterwards. Extrapolation of the survivorship curve suggests 

 that approximately one-third of the plants at Sheep Corral Gulch 

 live to be 14 years old. Life expectancy at Haynes Creek is 

 somewhat lower. 



Results of the study indicate that the two populations were 

 stable or increasing in size during the past seven years. 

 Mortality and recruitment were highly variable among years, and 

 patterns of mortality and recruitment were only partly congruent 

 between the two sites. These observations suggest that mortality 

 and recruitment are dependent on yearly climatic fluctuations. 

 Indeed, mortality was negatively correlated with fall and winter 

 precipitation, and recruitment was associated with warm fall 

 temperatures. These correlations are based on very small sample 

 sizes and must be viewed as tentative. Data acguired in future 

 years should help elucidate the relationships between climate and 

 life history parameters. 



Number of fruits per reproductive plant did not differ 

 significantly between the two sites; however, the proportion of 

 reproductive plants was higher and less sporadic at Haynes Creek 

 than at Sheep Corral Gulch. 



Reduction in reproductive effort due to inflorescence and 

 seed predation was high, averaging 42% at both sites. Although 

 reduced fecundity can have adverse effects on plant populations 

 (Greig-Smith and Sagar 1981, Hester and Mendelssohn 1987, Cabin 

 et al. 1991), population sizes were stable or increased during 

 this study. Nonetheless, such high levels of predation could 



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