among the other 10 months (Bengeyfield and others 

 1980). The vegetation surrounding the area is dominated 

 by lodgepole pine (Pinus contorta) with a sparse under- 

 story of species such as Oregon-grape (Berberis repens) 

 and mountain lover (Pachystima myrsinites). Small 

 patches of aspen (Populus tremuloides) are interspersed 

 throughout the lodgepole pine, and broad meadows with 

 species such as tufted hairgrass (Deschampsia cespitosa) 

 and muttongrass (Poa fendleriana) follow the major 

 drainages. 



Study Design 



The study included three seeding density treatments 

 and two fertilizer treatments in a randomized block de- 

 sign with three replications of each treatment. Each rep- 

 lication was 6.1 by 30.5 m. The density treatments con- 

 sist of a constant density of natives (215/m 2 ) seeded with 

 (1) no introduced grasses, (2) an equivalent density of 

 introduced grasses (215/m 2 ), and (3) three times the den- 

 sity of introduced grasses (645/m 2 ) (table 1). Seeding 

 densities were based upon pure live seed (PLS) and deter- 

 mined from recommended levels of seeding densities for 

 mined land revegetation in general and for seeding mix- 

 tures of natives specifically (USDA FS 1979). 



The fertilization treatments I chose were nonfertiliza- 

 tion and an "optimal" level. I based the "optimal" level on 

 the recommendations of Tiedemann and Lopez (1982) and 

 took into account the initial levels of N, P, and K in the 

 soil. The levels and forms of nutrients were 56 kg/ha of N 

 applied as NH 4 N0 3 , 56 kg/ha of P applied as P 2 5 , and 28 

 kg/ha of K applied as KjO. 



Seeding Mixture 



Table 1 contains a complete list of the species used in 

 this study. The introduced grasses were chosen on the 

 basis of their ability to perform well under climatic and 

 edaphic conditions similar to those that exist on the study 

 site (Thornburg 1982). I selected native species that 

 were colonizers on similar disturbed sites in the area. 



Seeds of introduced grasses, native shrubs, and western 

 yarrow were purchased. Seeds of the other native species 

 were collected adjacent to the study site during the fourth 

 week of August, allowed to dry for 1 week, and then 

 threshed. Seed weight and number per gram were deter- 

 mined by weighing three replications of 100 seeds of each 

 species. Seed viability of the collected native species was 

 determined from a standard tetrazolium test (Moore 

 1972). Collected native seeds were about 99 percent pure. 



Table 1 — Numbers of pure live seeds for native and introduced species used in each treatment 



Species 



Natives 

 only 



Natives and 

 low density 

 introduced 



Natives and 

 high density 

 introduced 



Pure live seed/m 2 



Introduced grasses 



Intermediate wheatgrass (Agropyron intermedium) 

 Meadow foxtail (Alopecurus pratensis) 

 Smooth brome (Bromus inermis) 

 Orchardgrass (Dactylis glomerata) 

 Timothy (Phleum pratense) 



Subtotal 



43 

 43 

 43 

 43 

 43 



215 



129 

 129 

 129 

 129 

 129 



645 



Native species 

 Grasses 



Slender wheatgrass (Agropyron trachycaulum) 

 Tufted hairgrass (Deschampsia cespitosa) 

 Muttongrass (Poa fendleriana) 

 Spike trisetum ( Trisetum spicatum) 



Forbs 



Western yarrow (Achillea millefolium) 

 Everlasting (Antennaria spp.) 

 Silky phacelia (Phacelia sericea) 



Shrubs 



Saskatoon serviceberry (Amelanchier alnifolia) 

 Mountain big sagebrush (Artemisia 



tridentata vaseyana) 

 Woods rose (Rosa woodsif) 



Subtotal 



Total 



21.5 

 21.5 

 21.5 

 21.5 



21.5 

 21.5 

 21.5 



21.5 

 21.5 



21.5 



215 



215 



21.5 

 21.5 

 21.5 

 21.5 



21.5 

 21.5 

 21.5 



21.5 

 21.5 



21.5 



215 



430 



21.5 

 21.5 

 21.5 

 21.5 



21.5 

 21.5 

 21.5 



21.5 

 21.5 



21.5 



215 



860 



2 



