How did westward expansion and settlement impact native american?

Native Americans(my people) clashed with the U.S and the U.S military forces during this time period. Not only did we lose more of our land but also the buffalo migration was effected leaving our people with a food shortage. we had to give up our way of life or be killed. Many battles broke out resulting in 300 killed in the battle of little big horn and thousands more later. 

Ithink it iscommunism?