strong taxonomic preference. This inference could be invalidated 

 by the development of Rhinocyllus conicus strains with different 

 host preferences (Rees pers. commun.) . It was noted that musk 

 thistle ( Carduus nutans ) , an alternative weevil host, is common 

 below the Duck Creek Pass site in the Big Belt Mountains, while 

 it is limited or absent in the vicinity of Little Belt Mountains 

 sites (USDA Forest Service 1993). 



Using data in Tables 3 and 4, the net seed predation among 

 Neihart plants is crudely estimated at least 27%, and the net 

 seed predation among high- and low-density Russian Creek plants 

 is at least 35% and 15%, respectively. This contrasts with 

 results from Kings Hill #2 where predations levels may have been 

 as high as 61% and 46% in 1991 and 1992, respectively. These are 

 conservative estimates because it has been noted that Rhinocyllus 

 conicus also reduces the viability of unconsumed seeds in the 

 flowering head (Rees 1977) . 



It is recommended that weevil infestation monitoring be continued 

 throughout demographic monitoring, and seed predation levels 

 compared against seedling numbers in successive years. 



Hybridization monitoring 



Morphological results differ from 1992 results in that the 

 collective hybrid category is larger compared to any of the 

 categories for "pure" taxa (Table 6) . This is believed to 

 reflect on the more stringent distinctions between the hybrids 

 and parent taxa made in the 1993 field season compared to the 

 1992 field season rather than a hybridization trend. The need 

 for tighter definitions of these distinctions is to be met by a 

 set of illustrations that place flower heads in appropriate 

 categories. 



Hybridization monitoring results hinge on genetic analysis 

 (Brunsfeld in progress) . Preliminary results corroborate the 

 absence of "pure" Cirsium lonoistvlum sample sets, and indicate 

 that there may have even less of the "pure" component than 

 previously suspected. This interpretation is based on 

 morphological analysis of a single correlated set of bract 

 features, ambiguous by the standards of Wilson (1992) . If 

 hybridization is documented and a discrete Cirsium lonoistvlum 

 genome exists, then this taxonomic resolution thrusts us into the 

 conservation biology realm involving hybrids (Riesberg 1991) . 

 If, however, Cirsium lonaistylum is not taxonomically unique, 

 then monitoring research is to be discontinued. It is premature 

 to make status recommendations to either the U.S. Fish and 

 Wildlife Service or the U.S. Forest Service Region 1 Office at 

 this time. 



15 



