21 



obtained in biomass studies of populations of 

 M. primuloides from various elevations, 

 Douglas (1981) concluded that interspecific 

 competition reduces plant size at low 

 altitudes, resulting in reduced vegetative 

 reproductive allocation. On the other hand, 

 reduced competition at mid-elevations allowed 

 for higher vegetative reproductive 

 allocation. Finally, at the highest 

 altitude, plant size is reduced by the severe 

 environment, again lowering the vegetative 

 reproductive allocation. Thus, when 

 competition from other species arises, one 

 would expect the development of smaller 

 plants (stems) , which expend less energy on 

 vegetative reproduction. 



b. HERBIVORY: Mimulus primuloides is subject to 

 herbivory, and at least in one study site 

 observed by Douglas (1981), grasshoppers 

 ( Melanoplus devastator and Melanoplus spp.) 

 lowered seed production substantially. 



H. LAND OWNERSHIP OR MANAGEMENT 



1. Beaverhead National Forest 



Twin Lakes (001) 



Little Joe Meadows (002) 



Skull Creek Meadows (003) 



Odell Lake (005) 



Pine Creek (006) 



Odell Creek (007) 



Rock Island Lakes (008) 



Skull Creek (009) 



2. Bitterroot National Forest 

 Lost Trail Pass (004) 



II. ASSESSMENT AND MANAGEMENT RECOMMENDATIONS 



A. THREATS TO CURRENTLY KNOWN POPULATIONS 



1. GRAZING: By far the greatest threat to M. 

 primuloides in Montana comes from livestock 

 grazing in wetland/riparian situations. The Pine 

 Creek (006) population located in 1989, was 

 thought to be threatened by grazing (John Pierce 

 pers. comm. ) . In Montana populations, vegetative 

 reproduction was high, with few seedlings 



