What would happen if grasses and shrubs were removed from an ecosystem

C. the primary consumers would die out or move elsewhere 
An distortion in an ecosystem mainly like plants can insidious consequences in an ecosystem. With primary consumers dependent on autotrophs as the source of food and thus, energy if these resources are gone then they would probably die or migrate somewhere else.
Ecosystem composes both the biotic and abiotic factors that make up the entire ecological system balanced and functioning. If ever one factor has cease to exist and that special element plays a major role in the food chain, scarcity will lead to extinction. 

It is platinum in the market value