I. 10. A. 2. Performance under changed conditions: No management 

 practices currently exist that are designed 

 specifically for G. howellii . Apparently, G. howellii 

 does not survive in areas that have been treated with 

 Tordon, as evidenced by the decline of the Cottonwood 

 Creek (040) population. While it readily grows in 

 disturbed habitats such as roadsides, it cannot survive 

 heavy, continued road maintenance involving grading or 

 scraping, as indicated by the apparent extirpation of 

 the Blackfoot Roadside (035) population. 



I. 10. A. 3. Current management policies and actions: Mike Thompson 

 is now informed of G. howellii populations occurring on 

 the Blackfoot-Clearwater Wildlife Management area. 



The Idaho Natural Heritage Program is in the process of 

 writing a draft species management guide for this 

 species for the St. Joe National Forest. This should 

 be completed by summer, 1991. However, this guide may 

 not apply well to Montana populations, as Idaho 

 populations are quite localized (all occur within one 

 section of land (640 acres)), and occur in primarily 

 native habitat (forest openings) (Chris Lorain, Idaho 

 Natural Heritage Program, pers. comm.). 



11.12. General assessment of vigor, trends, and status: 



Seedling establishment was very good in 14 of the 

 populations resurveyed in 1990. Basal rosettes were 

 limited or not present, in six populations, which 

 suggests difficulty in germination and/or recruitment 

 from the seed bank. This may be due to drought or 

 competition. The Cottonwood Creek population (040) had 

 no flowering plants (only 4 basal rosettes were 

 observed) . No plants were observed at the Blackfoot 

 Roadside (035) population or at the main subpopulation 

 at Blackfoot Roadside II (036) ; road maintenance is 

 suspected to have eliminated both populations. 

 However, one subpopulation of 130 plants was located 

 l/8th mile north of the original population at 

 Blackfoot Roadside II (036) . Therefore, the entire 

 population was not extirpated. 



In Montana, Grindelia howellii is dependent on early 

 successional habitats most often provided by road 

 grading or road establishment. Nonetheless, 

 populations can also be extirpated by these same 

 activities or through weed control activity. 



Trends in population status are not easy to estimate 

 from only two censuses (1986 and 1990). By 1990, more 



