2. Topography: In the study area, this species is confined 

 to steep upper escarpment slopes. 



3. Soil relationships: Douglas' dusty maiden typically 

 occupies droughty soils. In the study area, it is restricted 

 to gravelly calcareous loam. 



Population biology and biological interactions 



1. Population size and condition: Population density was 

 low and population numbers low, spread out in discrete 

 subpopulations on three separate ridgelines. They are 

 oriented basically downwind (southwest to northeast) of one 

 another. The largest subpopulation is at the southwesternmost 

 end, a core from which the sayellite subpopulations disperse. 

 Over 75% of the population is made up of plants in rosette 

 form. It is not known whether these are all juveniles, or 

 whether plants which flowered in past years "regressed" under 

 the harsh 1994 growing season conditions. 



2. Reproduction: Polycarpic, the concurrent flowering 

 making pollen exchange within the same individual likely. 



3. Competition: This species does not occur in the 

 surrounding prairie communities in which competition for water 

 and light are high compared to its sparsely-vegetated habitat. 

 The south flank of Slim Buttes also has potential habitat but 

 is heavily invaded by yellow sweet clover (Melilotus 

 officinalis ) , which alters the course of succession in its 

 nitrogen-fixing capacity, out-competing many early-succession 

 species. 



4. Herbivory: Two individuals had the oldest flower head 

 browsed off. This is likely to represent indiscriminate 

 browsing early in the season, indicating low levels of 

 herbivory. 



Assessment and management recommendations: The Chaenactis 

 douqlasii is not recommended for further consideration as 

 sensitive by the U.S. Forest Service because of few threats 

 and its presence in distant units of the District on both 

 sides of the state line. 



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