Why was dances with the wolves considered the first environmental western?

Answer 1

Dances with Wolves (1990) is a motion picture adapted from the 1988 book by Michael Blake. It was produced, directed by and starred Kevin Costner who is active in supporting environmental causes. The film portrays the Native Americans as being in harmony with nature, whereas the Americans descended from European immigrants were not.

Of particular note is the 'buffalo hunt' sequence, which is somewhat graphic and emotionally resonant. During the historical period depicted in the film, many Native Americans depended upon the buffalo herds for meat and hides, but they often used traditional weapons and hunting strategies and did not over hunt. The immigrant descended Americans hunted the buffalo to near extinction. The buffalo were merely slaughtered using rifles, and while hides were harvested, the meat was generally left to rot.

The Native Americans were employing methods consistent with what we would call 'conservatism' today.