The Black Hills Group of the Sierra Club has determined in a two-year study of livestock grazing on the Northern Hills Ranger District, Black Hills National Forest that overgrazing is widespread. This is a violation of the Forest Service's contract with the people of the Black Hills and, indeed, the nation as represented in the Land Management Plan for the Black Hills National Forest. Despite attempts to settle this issue locally, Forest Service land managers have refused to credit the information presented to them despite the fact that the data were collected by a professional range scientist. Overgrazing is negatively affecting hunting, fishing, recreation, water quality, and population viability for locally rare species like the American dipper.