recruitment by dividing the reproductive+recruitment elasticities 

 proportionately between the two components. 



I surveyed a large Astragalus scaphoides population at 

 Hayden Creek, Idaho in late May, 1990 for inflorescence 

 predators. Insects observed girdling stems were collected and 

 sent to the Montana State Entomology Lab in Bozeman for 

 identification. 



RESULTS 



Population Growth 



The number of Astragalus scaphoides plants in the transects 

 at both sites increased by about one third between 1986 and 1993 

 (Fig. 1) . Equilibrium population growth rate (X) was near or 

 above 1.0 at both sites over the course of the study and was 

 greater than 2.5 at Sheep Corral Gulch in 1988-89 and 1990-91. 

 At no time during the study was A. less than 0.8 at either site 

 (Fig. 2, Appendix B) . 



Survivorship 



Nearly 50% of the plants observed at the start of the study 

 in 1986 were still alive in 1993 (Fig. 3) . The first large bout 

 of recruitment during my study occurred in 1989 at Sheep Corral 

 Gulch and in 1988 at Haynes Creek. Survivorship curves for these 

 cohorts are shown in Fig. 3. Fifty percent of Astragalus 

 scaphoides plants survived for more than 3-4 years. Taken 

 together these results suggest that A^ scaphoides is a long-lived 

 perennial, with 50% mortality occurring in the first 3-4 years, 

 but a large proportion of plants living to be ten years or older. 



Reproduction and Predation 



Reproduction varied greatly among years at the two sites 

 (Fig. 5) . At Sheep Corral Gulch, the proportion of reproductives 

 was less than 5% in four out of eight years, while at Haynes 

 Creek at least 10% of the population was reproductive in all but 

 one year. The proportion of reproductive plants was higher at 

 Haynes Creek in all eight years of the study. 



Predation of whole inflorescences was typical at both sites 

 and can have two possible sources: (1) livestock or (2) insects. 

 Livestock predation was observed only at Sheep Corral Gulch in 

 1989, 1990 and 1993. Ants (Subfamily Formicinae) and moth larvae 

 ( Melacosoma spp. , Family Lasiocampidae) were observed removing 

 inflorescences at a site near Haynes Creek in Idaho, and similar 

 damage was observed at both study sites. I did not distinguish 

 between these two sources of inflorescence predation. 



