The video basically says it all;

This land has an extremely important spiritual significance to the native people of the area, and the owners are looking to sell it in the near future. Certain parties have expressed interest in running a highway through the land, so the seven bands of the Oceti Sakowin are trying to pool their resources to buy, if not all 2000 acres, at least enough strategic plots to prevent the construction. They have an Indiegogo page set up to accept donations from the general public, as well as more information over here.