Nutritional and developmental responses of three mountain bunchgrasses to summer cattle and winter elk grazing

E lk-L ivestock S tu d ies i n Montana was e s t a b l i s h e d to s tu d y e l k l i v e s t o c k i n t e r a c t i o n s th ro u g h c o o p e r a t i v e r e s e a r c h p rog ram s o f v a r io u s s t a t e and f e d e ra l agencies . The o b je c t iv e s of E lk-L ivestock S tu d i e s w e re : I) t o d e te r m in e th e i n f l u e n c e o f v a r i o u s c a t t l e management p r a c t i c e s on e lk and t h e i r h a b i t a t s , 2 ) t o e v a l u a t e a l t e r n a t i v e m anagement p r a c t i c e s , and 3) t o d e v e lo p b e n e f i c i a l g u i d e l i n e s f o r d u a l use o f th e a v a i l a b l e r e s o u r c e . T h is r e s e a r c h p r o j e c t f e l l w i t h i n o b j e c t i v e one, and i t s o b j e c t i v e s w e re : I) to q u a n t i fy the e f f e c t s of summer c a t t l e g raz in g a t v a r io u s phonological s t a g e s on t h e w i n t e r n u t r i t i o n a l v a l u e s o f t h r e e m o u n t a i n bunchgrasses, and 2) to q u a n t i fy the e f f e c t s o f w in te r e lk g raz ing on th e growth and development i n th e fo l lo w in g sp r in g o f the same th re e s p e c i e s . Rough f e s c u e ( F e s tu o a s c a b r e l l a ). Id ah o f e s c u e ( F e s tu c a i d a h o e n s i s ) and b luebunch w h e a tg r a s s (A groovron s b i c a t u m ) were th e sp ec ie s s tud ied . The study was conducted on the South Crow e lk w in te r range in th e Elkhorn Mountains of Montana. For o b je c t iv e one a random ex per im en ta l design of one f a c t o r w ith th re e l e v e l s and nine t re a tm e n ts was used. The g ra s s sp ec ie s were the f a c t o r l e v e l s and the t re a tm e n ts c o n s is te d of the phenolog ies! s tage when g r a z i n g had o c c u r r e d p lu s an u n g razed s t a g e . W in te r c h em ica l c o n s t i tu e n t v a lu e s were the dependent v a r ia b le s . For o b je c t iv e two a randomized block design having one f a c to r w ith th re e l e v e l s and two t r e a t m e n t s i n f i v e b lo c k s was used . S i t e s , s p e c i e s , g r a z in g , and s t a n d i n g d e a d w e r e t h e b l o c k s , f a c t o r and tw o t r e a t m e n t s , r e s p e c t i v e l y . The d e p e n d e n t v a r i a b l e s w e re p l a n t h e i g h t and phenolo g ical s tage on s ix sp r in g sam pling da tes . None of the summer g raz ing t r e a tm e n ts a f fe c te d rough fescue or bluebunch w heatg rass w in te r n u t r i t i o n a l va lues , and grazed p la n ts were s i m i l a r to u n g razed p l a n t s . Some pheno l o g i c a l s t a g e s of summer g r a z in g w ere r e f l e c t e d i n Idaho f e s c u e w i n t e r c h e m ic a l c o n s t i t u e n t v a l u e s , bu t no managem ent s i g n i f i c a n c e cou ld be a t t a c h e d to th e d i f f e r e n c e s . W in te r g r a z i n g d id n o t a f f e c t s p r i n g l e a f l e n g t h s in-vrough fescue or bluebunch w heatg rass , and only o c c a s io n a l ly affected^ Idaho f e s c u e s p r i n g g ro w th . The p re s e n c e of s t a n d i n g dead i n th e s p r i n g r e s u l t e d i n l o n g e r Id ah o f e s c u e l e a v e s i n th e n e x t s p r in g . N e ither rough fescue nor bluebunch w heatg rass sp rin g l e a f le n g th s were a f fe c te d by the presence of o v e r w i n t e r i n g r e s i d u a l m a t e r i a l . These r e s u l t s w e r e d i s c u s s e d f ro m t h e p e r s p e c t i v e o f t h e w i n t e r p h y s io lo g ica l a c t i v i t y of each sp ec ie s of g rass .