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 inventories can detect trends but will do little 

 to determine causality or help generate predictive hypotheses (Palmer 1987). Long-term 

 conservation requires a knowledge of many life history parameters including fecundity, 

 recruitment, survivorship, age structure, and population flux. Demographic monitoring 

 techniques can provide information on factors regulating population density and persistence 

 (Palmer 1987). This information, in turn, provides an essential basis for management 

 decisions. 



Sapphire rockcress ( Arabis fecunda Rollins) is a rosette-forming perennial in the 

 Mustard Family (Brassicaceae). This recently described species (Rollins 1984) is endemic to 

 highly calcareous, azonal soils in the foothills of the Sapphire Range in Ravalli County and in 

 the Pioneer Range in Beaverhead and Silver Bow counties, Montana (Lesica 1985, 

 Schassberger 1988). Arabis fecunda generally occurs on steep, often eroding slopes with low 

 vascular plant density. In Ravalli County, populations of A^ fecunda are thought to be 



