68 



earlier, the species shows a preference for 

 microsites which are moister than the 

 surrounding habitat, and this preference may 

 be a result of differential percentages of 

 seed germination and subsequent seedling 

 development . 



6t. Survival and mortality: No quantitative 



information; the plants do not appear to 

 tolerate shade. 



7. Overall assessment of taxon's reproductive 



success: Reproduction appears to be vigorous 

 and adequate in nearly all of the papulations 

 studied. The main factors influencing 

 reproductive success relate to past and 

 present effects of human activities. The 

 species tolerates, and in the majority of 

 populations prefers, habitat disturbance. 

 Though such activities may result in the 

 destruction of some populations, the observed 

 reproductive success of the species suggests 

 that it may persist in fluctuating numbers 

 over the Montana portion of its range, and in 

 certain areas can increase in abundance 

 owing to habitat disturbance. 



8. Population ecology of taxon. 



A. General summary: Gr i nde 1 i a ho we 1 1 i i occurs 

 primarily in disturbed habitats, most often along 

 logging roads and trails, and in disturbed pine 

 plantations. In native, undisturbed grassland 

 habitats (i.e., Blanchard Flats (005)) it is less 

 frequent. The taxon does not tolerate canopy 

 closure or complete shade. No specific obligate 

 relationships are known. 



B. Positive and neutral interactions: None known or 



observed . 



C. Negative interactions. 



1. Herbivores, predators, pests, parasites and 

 diseases: None specifically known? owing to 

 the sticky-resinous inflorescences, Gr i nde 1 i a 

 howel 1 i i is very unpalatable, and in some 

 heavily grazed areas was the only species 

 1 eft ungrazed . 



S. Competition. 



a. Intraspecif ic : No quantitative 



information; some populations are very 

 dense (i.e., Cozy Corners (0^7)), but 

 competitive effects were not 

 superficially noticeable. 



