▁land ▁( O ls en ▁ 1 9 9 7 ). ▁The ▁United ▁States ▁government ▁bought ▁up ▁much ▁of ▁this ▁land ▁through ▁the ▁Land ▁Util ization ▁Program , ▁with ▁management ▁eventually ▁controlled ▁by ▁the ▁United ▁States ▁Forest ▁service ▁and ▁the ▁Bureau ▁of ▁Land ▁Management ▁( W oot en ▁ 1 9 6 5 ; ▁O ls en ▁ 1 9 9 7 ). ▁During ▁the ▁dr ought ▁years ▁of ▁the ▁ 1 9 3 0 s , ▁these ▁ag encies ▁re - ve get ated ▁some ▁of ▁these ▁areas ▁with ▁non - native ▁highly ▁compet itive ▁veget ation ▁such ▁as ▁smooth ▁b rome ▁( B rom us ▁in erm is ) ▁and ▁cr ested ▁whe at gr ass ▁( Ag ropy ron ▁crist atum ) ▁( US DA - ▁US ▁Forest ▁service ▁ 2 0 0 1 ). ▁These ▁plants ▁served ▁their ▁purpose ▁by ▁re - ve get ating ▁and ▁protect ing ▁the ▁soil . ▁But ▁these ▁inv aders ▁became ▁great ▁compet itors ▁and ▁directly ▁affected ▁native ▁veget ation . ▁In ▁some ▁instances ▁cr ested ▁whe at gr ass ▁and ▁smooth ▁b rome ▁have ▁forced ▁out ▁native ▁veget ation , ▁creating ▁mon oc ulture ▁habit ats . ▁Mon oc ulture ▁habit ats ▁are ▁not ▁fav ored ▁by ▁sharp - ta iled ▁gr ouse , ▁as ▁they ▁prefer ▁sites ▁with ▁high ▁heter ogene ity . ▁H amer st rom ▁( 1 9 3 9 ) ▁was ▁quoted ▁as ▁saying ▁" More ▁important ▁than ▁the ▁individual ▁cover ▁plants ▁is ▁the ▁fact ▁that ▁most ▁of ▁the