8 



summers, and cold, snowy winters. The highest 

 amounts of precipitation come in the form of rain 

 in spring. 



The weather collection site at Hamilton is 

 approximately 5 miles west, and 1000 feet lower 

 than the 4 populations located along the flanks of 

 the Sapphire Mountains. For the period from 1951- 

 1980, the July mean temperature was 67.0° F, the 

 January mean was 25.0° F, and the mean annual 

 precipitation was 13.11 inches. The long-term 

 weather station nearest to the populations in the 

 East Pioneer Mountains is at Divide. This station 

 is approximately 3.5-20 miles distant from the A. 

 fecunda sites, and at an elevation of 5,395 feet. 

 This is up to 2,500 feet lower than some of the A. 

 fecunda sites. At Divide, the July mean 

 temperature was 63.3 °F, the January mean was 19.1 

 °F, and the average annual precipitation was 12.39 

 inches (U.S. Department of Commerce 1982). 



POPULATION DEMOGRAPHY AND BIOLOGY 



1. PHENOLOGY: The phenology of the A. fecunda 

 populations is variable due to the wide range in 

 elevations at which they are found (4,600 - 8,000 

 feet) , and differences in their topographical 

 position. At lower elevation sites or sites with 

 a more southern aspect, or in dryer habitats, A. 

 fecunda begins to flower in early May. Mature 

 fruit is present from late May-June on (Lesica 

 1985) . At higher elevations, or on sites with a 

 more northern or western exposure, flowering and 

 fruiting may extend into early July. 



2. POPULATION SIZE AND CONDITION: Populations of A. 

 fecunda range in size from 75 to 10,000 plants 

 with an average size of about 1,000. Most of the 

 populations along the flanks of the Pioneer 

 Mountains are in good condition. However, the A. 

 fecunda populations along the flanks of the 

 Sapphire Mountains have been invaded by various 

 introduced species. Interspecific competition 

 with Centaurea maculosa is of primary concern at 

 these locations. Transects were established at 

 Charleys Gulch (001) and Birch Creek (004) in 

 Ravalli County, to gather information on life 

 history and population trends for A. fecunda . 

 Reports from an ongoing study of the interactions 

 between these two species is contained in 

 Schassberger (1988, 1990). The effects of 

 Centaurea maculosa invasion on the fecundity of A. 



