1 



INTRODUCTION 



In order to adequately protect populations of an organism, 

 it is necessary to understand its life history and population 

 dynamics (Massey and Whitson 1980, Sutter 1986, Palmer 1987). 

 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 occurs on eroding slopes with low vascular plant density 

 but often a relatively high cover of cryptogamic soil crust. In 

 Ravalli County, populations of Arabis fecunda are thought to be 

 threatened by livestock grazing and encroachment by an aggressive 

 exotic weed, spotted knapweed (Centaurea maculosa) (Lesica 1985) . 

 Arabis fecunda is a candidate for listing as a threatened or 

 endangered species by the U.S. Fish and Wildlife Service (USDI, 

 FWS 1990) and is considered threatened in Montana (Lesica and 

 Shelly 1991) . 



This paper is a progress report on a long-term demographic 

 monitoring study of A^ fecunda populations, established in order 

 to determine important life history attributes and determine 

 trends in overall recruitment and mortality. 



