Bureau of "Land" Management

The new director of the Bureau of Land Management, the government agency that controls Federal lands, has done something pretty appalling. He has exempted certain activities--like grazing, oil exploration and forestry--on Federal lands from the requirements of the National Environmental Policy Act. See a full article from Daily Green here http://www.thedailygreen.com/2007/08/14/gov-exempts-258-million-acres-from-environmental-review/5194/.

My question--does he have the authority to do so? I think it would certainly be up for legal challenge--can an executive branch official relieve obligations under a legislative branch mandate?