54 



Dependence of this taxon on natural 

 disturbance: Gr i nde 1 1 a howel 1 i i occurs most 

 frequently in areas of disturbance; this 

 disturbance has most often resulted from 

 human activities, i.e., road-building, 

 logging, and grazing of livestock. Thus, it 

 is expected that natural disturbances, such 

 as erosion and flood scouring, could also 

 result in local increases in the abundance 

 of the species. At two sites (Spring Creek 

 (013), Monture Creek Access (0<+3)), many 

 individuals occur on river terraces which 

 are undoubtedly subjected to periodic 

 flooding. Otherwise, a strict dependence on 

 natural disturbance was not noted. Large, 

 semi-natural sites in level meadows ( l .e. , 

 Cottonwood Creek (0^+0), Cozy Corners (0^7)) 

 are associated with stable landforms. 



Other unusual physical features: 



observed . 



None 



Biological characteristics. 



1. Vegetation physiognomy and community 



structure: Gr i nde 1 i a howe 1 1 i i is variously 

 associated with a. ) open grassland 

 communities, b. ) temperate evergreen conifer 

 forests dominated by trees with more or less 

 conical crowns, and c.) the forest border 

 ecotone between the first two types. 



Regional vegetation types: Largely within 

 areas of Western ponderosa forest ( Pi nus ) 

 and Douglas-fir forest ( Pseudo tsuqa ) , with a 

 small portion of the range nearing the 

 Foothills prairie ( Aqr opyr on - Fes tuca - 5 t i pa ) , 

 as mapped by Kuchler (196^+). Occurs in four 

 climax vegetation types mapped by Ross and 

 Hunter (1976): a.) Subalpine fir/Douglas- 

 fir /Ponder osa Pine Climax Forest, b.) 

 Subalpine F i r /Doug 1 as-F i r /Grand Fir Climax 

 Forest, c.) Silty Range site with Rough 

 fescue, Idaho fescue, bluebunch wheatgrass, 

 et a 1 . , and d.) Subirrigated and Wetland 

 Range site with tall reedgrasses, tufted 

 hairgrass, et a 1 . 



Frequently associated species: 



Native: Pi nus ponderosa Dougl.ex Laws.8. Laws 

 P. contor ta Doug 1 . ex Loud. 

 Pseudo tsuqa menz i es i i (Mirb.) Franco 

 Larix occ identa lis Nutt. 



