Summary 

 We monitored individuals of Arabis fecunda over four consecutive years 

 at three sites in order to gain knowledge of this rare plant's life history. 

 Arabis fecunda is a short-lived perennial with high fecundity. Recruitment is 

 high as is mortality of juveniles. Plants flower by bolting or producing 

 axillary inflorescences. Bolting plants produced 2.5 times as many seeds, 

 matured earlier but had much higher mortality compared to axillary-flowering 

 plants. Seeds germinate readily without stratification. Seed dormancy is 

 induced by cold/dark conditions at some sites but not others. 



Recruitment rate, survivorship, age at maturity and fecundity varied 

 significantly among sites. Much of this difference in life history traits was 

 due to differential bolting frequencies among the three sites. These results 

 suggest that life history traits are locally adapted and that adaptive genetic 

 differences may exist between populations. 



Populations in the southern portion of A_^ fecunda' s range appear to be 

 stable and will be most sensitive to changes that cause a reduction in 

 recruitment. On the other hand, populations in the north may be declining and 

 should be most sensitive to declines in adult survivorship. 



Introduction 

 Passage of the Federal Endangered Species Act of 1973 and subsequent 

 recognition of the value of conserving biotic diversity (Wilson 1988) have 

 resulted in many government agencies becoming active in species conservation. 

 Surveys to determine the location and size of populations of rare species are 

 being conducted on public lands throughout the west. These surveys are 

 necessary in any species conservation program; however, knowing the location 

 and size of populations at any one point in time is only the first step in a 

 long-term protection strategy. (Sutter 1986). Extinction is a process 

 requiring an understanding of population dynamics (Menges 1986). Periodic 



